i i.:.-..;.-,..-..- .v----.: Columbia ©nibersJitp;^^'^ in tf)c Citp of Mt\3} ^orfe*^° V7 COLLEGE OF PHYSICIANS AND SURGEONS Reference Library Given by A MANUAL PRACTICAL JIYCIENI'^ STUDENTS, PHYSICIANS, AND HEALTH OmCERS. BY CHARLES HARRINGTON, M.D., Late Professor of Hygiene in the Medical School of Harvard University. FOURTH EDITION, REVISED AND ENLARGED. BY MARK WYMAN RICHARDSON, M.D., Secretary to the State Board of Health of Massachusetts. ILLUSTRATED WITH TWELVE PLATES IN COLORS AND MONOCHROME, AND ONE HUNDRED AND TWENTY-FOUR ENGRAVINGS. LEA & FEBIGER, PHILADELPHIA AND XEW YORK. 1911. Entered uccordiiig to Act of Cougress, in the year 1911, by LEA & FEBIGEK, In the Office of the Librarian of Congress. All rights reserved. WtSTCOTT fc THOMSON, CLCCTROTYPERS, PHILAOA. WILLIAM J. DORNAN, PRINTER, PHILAOA. PREFACE TO THE FOURTH EDITION. Prior to his doparturc for Knt()ii had boon preparinfj^ for a revision oi" his Hygiene, the demand for which he foresaw. He had tlieu largely completed the chapters on Milk and Disinfection. His manuscript, as well as the remainder of the volume, have been brought to date by the present writer. Dr. Harrington's work had won its way to an enviable position in the literature of one of the most important branches of human knowledge. No eifort has been spared to main- tain its usefulness as an authoritative guide for all classes of readers interested in hygiene and sanitation. It is a pleasure to the writer to extend his thanks to those who have been of service to him in getting out this new edition, and especially to Mr. H. W. Clark, chemist in charge at the Lawrence Experiment Station, for his assistance in revising the section on Sewage Disposal. M. ^y. R. 144 State Hoxise, Boston, 1911. Digitized by the Internet Archive in 2010 with funding from Open Knowledge Commons http://www.archive.org/details/manualofpractica1911harr CONTENTS. CHAPTER I. FOODS 17 SkCTION 1. GlCNKHAL CONSIDERATIONS 17 The nutritive value of food.s, 17. Amount of food necessary, 18. Com- position of foods, 1*.). Protciids, 19. J'ats, 22. Carbohydrates, 22. Organic acids, 24. Inorganic salts, 24. Section 2. Animal Foods: Meats, Fish, Eggs, and Meat Products 24 Meats, 25. Digestibility, 2.5. Flavor, 25. Texture, 26. Effects of cooking, 26. Characteristics of good meat, 27. Comparative digesti- bility of meats, 28. Composition of meats, 28. Beef, 29. Pork, .30. Veal, 31. Mutton, 31. Lamb, 31. Poultry, 32. Horse meat, 32. Meat preparations, 33. Sausages, 33. Fish, 35. Digestibility, 36. Keeping qualities, 36. Composition, 38. Meat and fish and parasitic dis- eases, 38. Transmission of disease by meat, fish, and vegetables, 44. Tuberculosis, 46. Relation between human and bovine tuberculosis, 50. Typhoid fever and cholera, 58. Poisoning by meat and fish, 64. Due to substances normally present in the living organism, 64. Due to bacterial products in meats and fish, 65. Signs pointing to an epidemic, 68. Onset and course of symptoms, 68. Nature symptoms, 69. Post-mortem appearances, 69. Character of meats which cause poisoning, 70. Cases illustrative of poisoning by fish and meat, 72. Poisoning by mussels, 72. Poisoning by herrings, 73. Poisoning by salmon, 74. Poisoning by pike, 75. Poisoning by oysters, 75. Poisoning by veal, 76. Poisoning by pork, 78. Poisoning by beef, 84. Poisoning bj^ horse meat, 86. Poisoning by sausages, 87. Poisoning by kid meat, 89. Meat inspection and slaughter- ing, 89. Eggs, 91. Lard, 94. United States standards, 94. Section 3. Milk and Milk Products 95 United States standard, 95. Composition of milk, 96. Fat, 97. Milk- sugar, 98. Proteids, 99. Mineral matter, 99. Specific gravity of milk, 99. Reaction, 99. Appearance, 99. Taste, 100. Koumiss and kefir, 101. Colostrum, 102. Consistence of milk, 102. Fennents of milk, 103. Trypsin or galactose, 104. Pepsin, 104. Diastase or amj-lase, 104. Lipase, 104. Salol-splitting ferment, 105. Oxj-dases, 105. Reductases, 105. Bacteria in milk, 105. Lactic ferments, 106. Peptonizing ferments, 107. ButjTic ferments, 107. Number of bacteria in milk, 107. Preserva- tion of milk, 114. Cold, 114. Heat, pasteurization, and steriUzation, 114. Objections to heat, 115. Chemicals, 118. Boric acid and borax, 118. 7 8 CONTENTS. PAGE Formaldehyde, US. Adulteration of milk, 122. Cream, 12-4. United States standard, 124. Condensed milk, 124. Milk as a factor in the spread of disease, 125. Poisonous milk, 125. Milk from diseased cows, 127. Milk contaminated from without with organisms related to human diseases, 136, Analysis of milk, 14G. Determination of specific gravity, 147. Determination of fat, 14S. Determination of total solids, 151. Determina- tion of milk-sugar, 152. Determination of ash, 153. Determination of proteids, 153. Detection of added water, 154. Coloring matters, 158. Detection of preservatives, 160. Methods of distinguishing between raw and cooked milk, 162. Detection of gelatin in cream, 163. Detection of sucrate of lime in cream, 164. Butter, 164. United States standard, 164. Butter as a carrier of disease, 167. Analysis of butter, 169. Deter- mination of the nature of the fat, 169. Cheese, 173. Composition, 175. Adulteration of cheese, 175. Analysis of cheese, 176. Cheese as a cause of poisoning, 175. Section 4. Vegetable Foods 177 Farinaceous seeds, 178. Cereals, 178. Wheat, 178. Composition of wheat, 179. Wheat flour, 179. Preparations of wheat flour, 180. Bread, 180. Composition of wheat bread, 183. Adulteration of flour, 184. Bleaching of flour, 185. Rye, 185. Barley, 186. Oats, 186. Corn, 187. Rice, 189. Buckwheat, 189. Legumes, 190. Peas, 191. Beans, 191. Lentils, 192. Farinaceous preparations, 193. Sago, 193. Tapioca, 193. Arrowroot, 193. Fatty seeds, 193. Almonds, 194. Cocoanuts, 194. Wahiuts, 194. Peanuts, 194. Chestnuts, 194. Vegetable fats, 195. Olive oil, 195. United States standard, 195. Cotton-seed oil, 196. Tubers and roots, 196. Potatoes, 196. Sweet potatoes, 199. Artichokes, 199. Roots, 199. Herbaceous articles, 200. Fruit, products used as vegetables, 201. Fruits, 201. Apples, 201. Pears, 202. Peaches, 202. Apricots, 202. Plums, 202. Cherries, 202. Oranges, 202. Grapes, 203. Melons, 203. Bananas, 204. Figs, 204. Berries, 204. Edible fungi, 205. Mushrooms, 205. Saccharine preparations, 206. Cane-sugar, 205. Maple sugar, 206. Glucose, dextrose, 206. Molasses, 207. Honey, 208. Con- fectionery, 209. Jellies and jam, 210. Section 5. Beverages 210 Stimulant beverages containing alkaloids, 210. Tea, 210. Adulteration of tea, 212. Coffee, 213. Cocoa, 215. Milk chocolate, 217. Fermented alcoholic beverages, 217. Beer, 217. Process of manufacture of beer, 219. Substitutes for barley malt, 220. Substitutes for hops, 221. Physical properties and chemical composition of beer, 222. Adulteration of beer, 222. Analysis of beer, 223. Determination of beer, 223. Table showing percentage of alcohol by weight and by volume, 224. Analysis of beer, 229. Determination of methyl alcohol, 229. Determination of extract, 232. Detection of preservatives, 233. Salicylic acid, 233. Fluorides, 233. Method of Hefelmann and Mann, 233. Brand's method, 233. Other determinations, 233. Total acidity, 233. Fixed and volatile acidity, 233. Ash, 234. Wines, 234. Classification of wines, 235. Composition of wines, 236. Adulteration of wines, 236. Analysis of wines, 238. Deter- mination of alcohol, 238. Detection of coal-tar colors, 239. Detection of preservatives, salicylic acid, 240. Formaldehyde, 240. Sulphites, 240. Cider, 240. Perry, 241. Distilled alcoholic beverages, 241. Brandy, 242. Whiskey, 243. Rum, 245. Gin, 245. Liqueurs, 245. (JON'VI'lN'l'H. 9 FAOa SkOTION 0. CfJNDIMKNTH, Rf'KJEH, AND HaKKKh' i\\\VM\V,K\M 246 Vincf^iir, 24('». (Jidcr viiicwir, 247. IJiiilcd Hl.uicH Hlandiinl, 247. Wiru; virioKar, 247. Mult, vific^^ar, 247. Siif^ar v'mcKur, 247. CJIiif,oH<; vinc«itr, 248. MoluHH(!H viruiKur, 248. AdulUTiUionH of \\\\v.v^,i.v, 248. Kxamina- tion of vitionar, 248. Acidii.y, 248. Lcmon-juicfi and litnf-juicc;, 249. Adulteration, 249. Salt, 249. MuHturd, 2.'')(). I'cfjpcjr, 250. Clov<«, 2r,0. Cinnamon and casHia, 251. AllHpicc, niii^cr, nutmeg, mace, Cayenne pc!i)|)('r, 251. Hiikiiiff powd(!rH, 252. Section 7. Food Putoservation 253 Cold, 254. Drying, 254. Salting, 2.54. Smoking, 254. Canning, 2.54. Chemical treatment, 250. Horie aeid and borax, 2.58. Salieylie aeid, 261. Sulphites, 2()2. I<\)rnia,ld(hyde, 202. Hydrogen peroxide, 20.'i. Sodium fluoride, 204. Sodium biearhonate, 264. Section 8. Contamination of Foodh by Metals 264 Copper, 264. Lead, 266. Zinc, 267. Nickel, 267. Tin, 267. Metallic Contamination from kitchen utensils, 267. CHAPTER II. AIR 269 Oxygen, 269. Nitrogen, 271. Argon, 272. Hydrogen, 272. Carbon dioxide, 272. Ozone, 274. Ammonia, 275. Nitrogen acids, 275. Aqueous vapor, 276. Dust and micro-organisms, 278. Carbon monoxide, etc., 280. "Sewer gas," 282. Organic matters, 286. Effects of vitiated air, 286. The air as a carrier of infection, 290. Influence of fog, 297. Examination of air, 297. Determination of aqueous vapor, 298. Direct determination of moisture by weighing, 298. Determination of relative humidity by the wet and dry thermometer bulbs, 299. Glashier's table, 300. Table of tensions, 301. Determination of carbon dioxide, 303. Solutions required, 303. Process of analysis, 304. Corrections, 307. Example of method of reckoning CO, 309. Determination of CO by Wolpert's method, 309. Determination by Fitz's method, 310. Determination of carbon monoxide, 311. Determination of ozone, 312. Determination of dust, 313. Bacte- riological examination, 314. CHAPTER III. THE SOIL 316 Constituents of the soil, 318. Physical properties of soils, 319. Per- meability of soils, 320. Capacity for water and water-retaining capacity, 324. Soil temperature, 326. Changes in the character of soils due to chemical and biological agencies, 32S. Soil-air, 329. Soil water, 332. Sources of soil-water, 335. Loss of moisture by evaporation, 335. In- fluence of vegetation on soil moisture, 336. Other effect of vegetation upon the soil, 337. Pollution of the soil, 338. Bacteria of the soil, 340. Soil and disease, 342. Soil dampness and disease in general, 342. Soil and pulmonary tuberculosis, 343. Typhoid fever, 343. Cholera, 346. Bubonic plague, 346. Diphtheria, 347. Malaria, 348. Yellow fever, 348. 1 CONTE^'TS. PAGE Tetanus and malignant edema, 348. Anthrax, 349. Uncinariasis, 350. Goitre, 353. Epidemic diarrhea, 354. Examination of soils, 354. Per- meability to air, 356. Permeability to water, 357. Water capacity, 359. Capillarity, 359. Moisture, 359. Organic and volatile matters, 360. Determination of CO in soil-air, 360. Bacteriological examination of soil, 362. CHAPTER IV. WATER 364 Rain, 363. Surface waters, 364. Ground-waters, 365. Phj'sical and chemical characteristics of water, 367. Appearance, 368. Reaction, 369. Odor, 369. Taste, 371. Substances found normally in water, 371. Gases, 371. Carbon dioxide, 372. Organic matter, 372. Albuminoid ammonia, 375. Nitrates and nitrites, 375. Mineral matters, 377. Hardness, 378. Bacteria in water, 379. Water supplies, 382. Stored rain, 382. Surface waters, 384. Ground-waters, 385. Driven wells, 387. Bored wells, 388. Drainage area of wells, 391. Pollution of wells, 391. Filter galleries, 393. Classification of waters from the sanitary standpoint, 394. Purification of water, 396. Oxidation, 396. Dilution, 397. Sedimentation, 397. Bacterial action, 397. Vegetation, 397. Methods of purification, 398. Boihng and distillation, 404. Filtration, 404. Domestic filters, 404. Filtration of public supplies, 406. Mechanical filtration, 412. Destruc- tion of Algae, 412. Removal of hardness, 413. Removal of iron, 414. Action of water on lead and other metals, 414. Action on iron, 418. Action on zinc, 418. Action on tin, 419. Water and disease, 420. Dis- orders connected with mineral matter, 421. Disorders connected with or- ganic pollution, 423. Typhoid infection of water supplies, 425. Influence of introduction of public water supplies on typhoid rates, 426. Examples of typhoid-fever epidemics and of limited outbreaks traced to infected water, 429. Epidemic at Lausanne, Switzerland, 429. The Plymouth, Pa., epidemic, 430. Outbreak at Uvemet, 431. Epidemic at Ashland, Wis- consin, 431. Epidemic at Luneberg, 432. Epidemic at Zehdenick, 433, etc. Asiatic cholera, 436. The propagation of cholera in India, 438. Parasites and drinking-water, 438. Parasites and drinking-water, 441. Ice, 443. Chemical examination of water, 444. Collection of samples, 444. Determination of free ammonia and albuminoid ammonia, 445. Solutions required, 445. Apparatus required, 446. Nesslerizing tubes, 447. Determination, 447. Precautions, 448. Permanent ammonia, standards, 449. Determination of other nitrogen compounds, 4,50. Deter- mination of nitrogen as nitrates, 450. Permanent nitrate standards, 451. Determination of nitrogen as nitrates, 451. Determination of chlorine, 4.52. Determination of residue, 453. Determination of hardness, 453. Solutions required, 453. Determination of "oxygen required," 454. Solutions required, 454. Determination of color, 455. Determination of odor, 455. Determination of reaction, 455. Determination of turbidity, 456. Detection and determination of lead, 456. Detection of zinc, 458. Detection of tin, 459. Detection and determination of iron, 459. Infer- ences as to character of water from the results of sanitary chemical analysis, 459. Bacteriological examination of water, 462. Collection of samples, 463. Planting the samples, 463. Quantitative determination, 464. Quali- tative determination, 465. Comparative value of chemical and bacte- riological analysis of drhikmg-water, 467. CONTh'N'/'S. 11 PAOB TIAIUTA^IMONS, SCHOOLS, I'l'IXJ 470 SiO(!'i'i()N I. (j!knioiiai, ( !()Nsii)KI{ath)Nh 470 Ah|)(!(!I,, 470. (lon.sl.nuil.iori nrul !irrririK(!rri(!n(,, 470. (Inn- of liabitationH, 471. S(!1k)()Im, 471. SrIiodI IHr nil luc, 472. CliuirH, 47'2. DcKkH, 472. IJIackhoiinlH, 47;{. Hioc'i'ioN 2. Vi'iNTrfiATioN ANr) IIkatino 473 Aiiiounl, of splice required for noml ventilation, 47r). Natural forc-oH in V(Mitiliiiioii, 47(). DilTusion ;i.ii(l fi;r;i,vily, 470. perflation and aHpiration, 47i). Natural veiH iliil Ktii, 4Sl. iiilet.s and oulIetH, 4H2. Mwlianical V(Miiilati()n, 4S.^). Artidtnal lieatJng in its relation to ventilation, 4H.'i. Radiation, 4S(). Conduction, 4.S(3. Convection, 480. Method.s of wann- ing, 487. ()|)en fires, 487. Stoves, 487. Furnaee^s, 489. Hot-water pijjcs, 48'.). Steam pipes, 489. llegulation of temperature, 490. Nccf*- sity of providing moisture, 491. Filtration of air, 493. Determination of rates of ventilation, 493. Section 3. LicniTiNfi 495 Natural lighting, 495. Artificial lighting, 497. Luminosity of flame, 497. Gas burners, 498. Varieties of illuminating gas, 499. Coal gas, 499. Water-gas, 499. Acetylene gas, 500. Impurities given off in lighting, .501. Gas pipes, 501. Fixtures, 502. Electric lighting, 502. Section 4. Plumbing 502 The soil-pipe and main drains, 504. Waste pipes, 509. Traps, 510. Ix)ss of seal, 516. Non-siphoning traps, 518. Water-closets, 520. The pan closet, 523. The plunger or plug closet, 524. Hopper closet, 525. Open wash-out closets, 525. Siphon closets, 526. Flushing apparatus, 528. Water-closet connections, 529. Urinals, 530. Wash-basins, 530. Bath- tubs, 532. Sinks, 534. House-maids' sinks, 535. Laundry tubs, 535. House service tanks, 535. Service pipes, 536. Testing plumbing, 537. CHAPTER VI. DISPOSAL OF SEWAGE 538 Methods of sewage disposal, 540. Discharge into the sea, 541. The pail system, 541. Sedimentation and chemical precipitation, 542. Sewage irrigation, 544. Influence of sewage irrigation on health, 545. The Waring system of irrigation, 547. Sewage filtration, 548. Contact filtra- tion, 550. Trickling filters, 551. The Cameron septic tank, 554. Septic tanks for the digestion of sludge only, 554. CHAPTER VH. DISPOSAL OF GARBAGE 556 Reduction, 559. CHAPTER Vni. DISINFECTANTS AND DISINFECTION 560 Pliysical agents, 560. Light, 560. Heat, 563. Steam. 565. BoiUng water, 568. Cold, 569. Chemical agents, 571. Non-metallic elements 12 CONTE^'TS. PAGE and their compounds, 572. Oxygen, 572. Ozone, 573. Hydrogen per- oxide, 574. Chlorine, 574. "Chloride of lime," bleaching powder, chlorin- ated lime, 575. Sodium hypochlorite solution, 577. Hypochlorous acid, 577. Iodine, 577. Bromine, 577. Sulphur dioxide, 577. Sodium car- bonate, 579. Sodium carbonate or washing-soda, 579. Lime, quicklime, 5S0. MctaUic salts, 581. Ferrous sulphate, 581. Ferric sulphate, 581. Ferric chloride, 581. Zinc chloride, 581. Aluminum chloride, 581. Potas- sium permanganate, 582. Copper sulphate, 582. Mercuric chloride or cor- rosive sublimate, 582. Mercuric cyanide, 584. Sublamin, 584. Silver compounds, 584. Sodium aurate, 585. Mineral acids, 585. Carbolic acid and cresol preparations, 586. Cresols, 587. Liquor crcsolis compositus, 588. Creohn, 589. Lysol, 589. Bacillol, 590. Saprol, 590. Solveol, 590. Sulfonaphthol, 590. Alcohol, 591. Essential oils, 593. Soaps, 594. Medicated soaps, 596. Lj'soform, 598. Paralysol, 598. Metakaline, 598. Formaldehj'de, 598. Methods of use and apparatus, 599. Germicidal properties, 606. Conditions favoring action, 607. Toxicity, 607. Amount necessary for room disinfection, 608. Disadvantages, 60S. Technic of room disinfection, 609. Other apphcations of formaldehyde, 609. Pre- vention of dissemination of infectious material; practical disinfection, 609. Disinfection of feces, 610. Urine, 610. Sputum, 611. Discharges from mouth, etc., 611. Eating utensils, etc., 611. Bed-linen and clothing, 611. Hands, 611. Air, 612. Room disinfection, 612. Disinfection of books, 616. Disinfection of water-closets, 616. CHAPTER IX. MILITARY HYGIENE 617 The recruit, 619. Examination of the recruit, 625. Chest capacity, 626. Grounds for rejection, 626. The hygiene of the soldier, 627. Personal cleanliness, 627. Contentment and cheerfulness, 627. Clothing of the soldier, 628. Wool, 628. Cotton and linen, 628. Shoddy, 629. Color, 629. Military dress coats, 629. Trousers, 629. Gaiters and leggings, 629. Head covering, 630. Stockings, 630. Boots, 630. Underclothing, 631. Abdominal bands, 632. Water-proof blankets, 632. The soldier's exercise and work, 633. Marching, 633. Care of the feet on the march, 638. Care of other parts, 639. The soldier's food: "rations," 639. Garri- son ration, 640. Field ration, 641. Travel ration, 641. Alcohol in the ration, 643. Preparation of food, 644. Is the United States ration suited to the tropics? 645. Posts and camps, 649. Sites, 651. Barracks, 652. Tents, 653. Huts, 656. Sewerage, 657. Sinks and latrines, 658. In- spections, 659. Sanitary police, 660. The diseases of the soldier, 665. Typhoid fever, 667. Dysentery, malaria, 668. Measles, 669. Diarrheal diseases in general, 669. Sunstroke, 669. Venereal diseases, 670. CHAPTER X. NAVAL AND MARINE HYGIENE 671 Naval recruits, 671. The naval ration, 672. Water supply, 675. The sailor's sleeping quarters, 676. The diseases of sailors, 677. Ventilation of vessels, 677. General hygiene of ships, 679. CHAPTER XI. TROPICAL HYGIENE 681 The soldier and the civilian in the tropics, 681. Residence, 683. Habitg aON'I'HM'S. 13 CAOB of lifo, (583. Tfic! UH(! of .-ihioliol in Ui<; (,roi)if;H, OSo. ("lothirij,?, 0H7. ('un; of the pcrHon, GS8. 'IVopical (liH(!iwcH, (JHS. (JIIAPTKK XII. THE RELATION Ol'' INSI'XnS TO HUMAN DISEASES 091 FIi(!H, m\. MciiH, (■.04. iicdhiijrH, (ior,. Ar:i(;lini(lH, (iOC. TirkH, (JOfi. liody l()iiH(!, (\S){). ]VIoH(|uit.o(;H, ()'.)(). Mfwfiiiit.ocs aii'l inaljiria, (»07. Tlir; lualari.'il parani(.(^, 700. I'lcvcuitivc. rnnaHiiroH, 700. .MoHfiuitocH and y»"llow fcvor, 707. Tlu^ yellow fcvor iiioHqui(,o, 709. I'rfivciitivf rnc-iwurcH, 711. Mosquitocvs and filarial discu.S(;, 712. MoH(jui(,o(;H and dengue, 714. CHAPTER XIII. hy(J11':n!o of occupation 716 Classifioal.ion of occupations, 721. Occupations involving exposure to air vitiated by rcspiratjon, 72:5. ()o(!Miiations involviii^ exposure 1o irritating and poisonous f^ases and fumes, 72)5. IrritaliuK ^\VH^'H and fumes, 724. Poisonous frases and fumes, 72.^). Occupation involving exposure to jKji.son- ous and irritating dusts, 729. Poisonous dusts, 720. Irritating dusts, 7;i2. Occupations involving exposure to infective matter in dust, 735. Occupa- tions involving tiie inhalation of ofTcsnsive gases and vapors, 73G. (Jccufia- tions involving exposure to extreme of heat, 737. Occupations involving exposure to dampness, 737. Occupations involving exposure to abnormal atmospheric pressure, 737. 0(H',upations involving constrained attitufle, 738. Occupations involving sedentary life, 730. Prophylaxis in general, 739. Employment of women and children, 740. CHAPTER XIV. VITAL STATISTICS 742 The census, 743. Estimated population, 745. Increase of population, 746. Population constitution, 746. Registrar's returns, 747. Marriage rates, 748. Birth-rates, 749. Death-rates, 751. Influence of sex, 751. In- fluence of age, 751. Influence of race, 752. Other influences, 753. In- fluence of density, 753. Weekly death-rates, etc., 754. Z.\Tnotic death- rate, 754. Infantile death-rate, 754. Death-rates of children, 756. High and low death-rates, 756. Correction of death-rate, 757. Classifica- tion of cause of death, 758. Registration of sickness, 7.58. Duration of life, 759. Probable duration of life, 759. Mean duration of life, 759. Expectation of life, or mean after-life-time, 760. Life tables, 760. CHAPTER XV. PERSONAL HYGIENE 762 Section 1. C.\re of the Person 762 Section 2. Regitlation of the Diet 764 Section 3. Rest and Recreation 764 Section 4. Physical Exercise 765 Effects of active exercise, 765. Circulation and respiration. 765. Skin, 766. Nervous system, 766. Digestive apparatus, 767. Ividnej-s, 767. Effect of exercise on weight, 767. Amount of exercise required. 768. I\ind of e.xercise, 769. Golf, 769. Wheeling, 770. Tennis, etc., 770. Rowing, 770. 14 CONTENTS. PAGE Section o. Clothing 770 Color, 770. Texture, 770. Hoat comluctivity, 771. Hygroscopicity, 771. Materials, 771. ^^'ool, 772. Silk, 773. Cotton, 774. Linen, 775. Rubber, leather, 77G. Fur, 776. Felt, 776. Adulteration of clothing, 776. . Chemical analysis, 777. Microscopical exaniination, 777. Poisonous dyes, 777. . Selection of clothing, 778. CHAPTER XVI. INFECTION, SUSCEPTIBILITY, IMMUNITY 780 Exciting causes of disease, 780. Channels of infection, 780. Infection and contagion, 781. Suscoiitibility, 781. Ehrlich's theory, 783. Toxins and antitoxins, 783. Bacteriolysis, 788. Hemolysis, 789. Complements, 793. Immune bodies, 795. Agglutinins, 796. Wassermann's reaction for syphilis, 800. Metschnikoff's theory, 801. Opsonins, 802. Practical applications of the results of studies in immunity, 802. Diphtheria, 804. Tetanus, 805. Hay-fever, 805. Dysentery, 806. Typhoid fever, 807. Asiatic cholera, 808. Bubonic plague, 809. Antistreptococcus serums, 811. Tuberculosis, 811. Cerebrospinal meningitis, 812. CHAPTER XVn. VACCINATION AND SMALLPOX 814 CHAPTER XVIII. QUARANTINE 820 Quarantine law of 1893, 822. Interstate quarantine, 826. State quaran- tine, 826. Sanitary cordon, 828. Municipal quarantine, 828. Camps of detention, 829. CHAPTER XIX. DISPOSAL OF THE DEAD 830 Earth burial, 830. Sites for cemeteries, 832. Cremation, 832. History of modem cremation, 834. PRACITICJAL HYGIENE. C 11 APT Eli I. FOODS. Section 1. GENERAL CONSIDERATIONS. Foods may be said to include everything taiven into the system capable of being utilized directly or indirectly to build up normal structure, repair waste, or produce energy in any form, but in the common ac(teptatiou of the term they include only those substances which can be oxidized in the system, thus excluding water and air, without which the functions of the body can not be performed. Diet is a mixture of food materials of various kinds habitually taken in such quantity as is needed to maintain or improve the condition of the system. The Nutritive Value of Foods. The potential energy of food is measured by the amount of heat which can be obtained by its complete combustion, and is expressed in units of heat or calories. The amount of energy required to raise the temperature of 1 kilogram of water 1° C. is known as a large calorie; that required to raise the temperature of 1 gram to the same extent is laiown as a small calorie; thus, 1 large calorie equals 1000 small calories. When the term is used without qualification, large calories are understood. These heat units correspond to 425.5 units of work ; that is to say, the same amount of energy required to raise the tempera- ture of the given weight of water 1° C. is sui!icient to raise 425.5 times the weight one meter. The amount of work done is expressed in kilogram-meters. The heat unit of the English system is the amount of energy required to raise the temperature of a pound of water 1° F., and its mechanical equivalent is 772 imits of work ; that is to say, the Siime amount of energy will raise 772 pounds one foot. According to the English method, work done is expressed in foot tons rather than in foot pounds. The calorimetric values of different food materials express also their 2 17 18 FOODS. physiological values as nutriment. Rubner* determined the calori- metric value of the proximate principles as follows : One gram of proteids ^= 4.1 calories. One gram of carbohydrates = 4.1 " One gram of fat = 9.3 " In the system, the carbohydrates and fats are burned completely to carbonic acid and water, but the proteids leave a residue of urea incapa- ble of still further oxidation. It is estimated that the ])iiysiological value of the proteids averages only about 75 per cent, of their calori- metric value. The calorimetric value of different foods of the several classes is not to be understood as bemg exactly the same. Thus, two kinds of sugar or two kinds of fat, or two kmds of proteid have not exactly the same calorimetric values, and the figures above given are to be under- stood only as fair averages. Rubner^ has determined by actual ex- perimentation the relative calorimetric values of certain food materials, and has shown that 100 grams of fat are equivalent to 225 of syntonin, or 232 of starch, or 234 of cane sugar, or 243 of muscle fiber, or 256 of grape sugar. In other words, these several amounts of food material are isodynamic. Amount of Food Necessary. For the maintenance of a proper degree of health and strength, the individual must ingest an amount of food sufficient to meet the daily loss of nitrogen and carbon. This must necessarily vary according to circumstances, and hence no rule can be laid down to fit all cases. The best that can be done is to make certain general rules based on the amount of Avork performed, for the greater the amount of work done, the greater the amount of food required to meet the necessary consump- tion of fuel and to repair the tissues. When performing heavy labor, the naturally increased desire for food is shown j)articularly in the direction of fats, and secondarily of proteids. For many years Voit's esthnate, that a man of 154 to 165 pounds, working at moderately hard labor 9 or 10 hours a day, requires 118 grams of proteid, 56 of fat, and 500 of carbohydrates, the whole yield- ing 3054.6 calories, has been generally accepted as correct. Recently, however, Chittenden^ has demonstrated conclusively by experiments extending over many months, the subjects being men engaged in intel- lectual pursuits, soldiers, and athletes in training, that half the stated amount of proteids is ample for the real physiological needs of the body under ordinary conditions of life, and that a fuel value of 3000 cal- ories is not necessary, the diminution in the proteid intake requiring no additional amount of non-nitrogenous substances. Knowing the composition of a given article of food, the proteid, fat, and carbohydrate value of a given weight can easily be determined ; and thus one can construct standard dietaries for the various conditions 1 Lehrbuch der Hygiene, Leipsic, 1900, p. 438. "'' Ibidem, p. 430. ^ Physiological Economy in Nutrition, New York. 1904. COMI'OSITION O/-' I'OODS. \'.) of" l)iir(! .sul>,sis(('ii(!c, rest, aixl pcrronn.'iiicc of v.'irioiis ;itin)iiiit- of" (|;iily labor. IJ|> i'O tl"' pi'csciil, fimc, it, Iiuk been (Misloiniiry lo \)Vi-M;r\\)(t llnj constituents ol" i\u\ ,st!iii(l;irei(y ol" precipitating; atpieoiis solutions (>[ other pr()t(!ins, |)oss(!SS stronjj; basic, |)roper(ies, and form stai)l(! saltH with strong niincnil acids. I'lx'y yi'^ld comparatively lew amino-acids, among which the basic amino-acids greatly |iredoiniiiat<;. 11. CoNJIKiATKD J'lU/rKINS. Substances which contain the ])rotein mohicnie united (o some other molccuh^ or molecules otherwise; than as a salt. [a) Nncleoproteins. Compounds of" one or more j>rotein moIecule.H with micleic! acid. (A) Glycoproteins. Compounds ((ftlie j)rotein molecule with a sub- stance or substances containing a carbohydrate group other than a nu(!leic acid. ((t) Phosphorproteins. Compounds of tlie protein nioleenle with some, as yet undefined, ])hosphorns-(!ontaining substance other than a nucleic acid or lecithins.' (d) Hiemoglobins. Compounds of the protein molecule with hema- tin or some similar substance. (e) Lecithoproteins. C^ompounds of the protein molecule with lecithins (lecithaus, phosphatides). III. Derived Proteins. 1. Primary Protein Derivatives. Derivatives of the protein molecule apparently formed through hydrolytic changes which involve only slight alterations of the protein molecule. (a) Proteins. Insoluble products which apparently result from the incipient action of water, very dilute acids, or enzymes. (6) Metaproteins. Products of the further action of acids and alka- lies whereby the molecule is so far altered as to form products solul)le in very weak acids and alkalies, but insoluble in neutral fluids. This group will thus include the familiar " acid proteins " and "alkali proteins," not the salts of proteins with acids. (c) Coagulated proteins. Insoluble products will result from (1) the action of heat on their solutions or (2) the action of alcohols on the protein. 2. Secondary Protein Derivatives.- Products of the further hydro- lytic cleavage of the protein molecule. (a) Proteoses. Soluble in water, uncoagulated by heat, and pre- cipitated by saturating their solutions with ammonium or zinc sulphate.^ ^ The aconmulated chemical evidence distinctly points to the propriety of classify- ing the phosphoproteins as conjvic:aled comjiounds, )'. €., they are possibly esters of some phosphoric acid or acids and protein. ^ The term secondary hydrolytic derivatives is used because the formation of the primary derivatives usually precedes the formation of these secondary derivatives. •* As thus defined, this term does not strictly cover all the protein derivatives com- monly called proteoses, e. g., heteroproteose and dyproteose. 22 FOODS. (b) Peptones. Soluble in water, iincoagulated by beat, but not pre- cipitated by saturating tbeir solutions -with ammonium sulphate/ (c) Peptides. Definitely characterized combinations of two or more amino-acids, the carboxyl group of one being united with the amino group of the other witli the elimination of a molecule of water.^ The albumins are not precipitated by alkaline carbonates, common salt, or dilute acids, but they are coagulated by being heated to 65°- 73° C. Casein, legumin, conglutin, syntonin, and albuminates, on the contrary, are not coagulable by heat, but are precipitated by common salt, sodium acetate, and trisodium phosphate. The albumoses are widely distributed throughout the vegetable kingdom, and are found largely m the cereals. In the animal kingdom, they are intermediate products of the action of pepsin on ordinary proteids, becoming even- tually converted to peptones. The collageus are very rich in nitrogen, but have an inferior nutritive value. Gelatin, for instance, contains 17—18 per cent., while the albumins contain but 16. Fats. — The fats are compounds of the triatomic alcohol, glycerin, with fatty acids, mainly stearic, palmitic, and oleic. These several compounds are known as stearin, palmitin, and olein. The two first mentioned are solids at usual temperatures, while olein is a liquid. Most fats are combinations of two or all of these substances, and some, as, for example, butter, contain additional glycerides in small amount. Stearin and palmitin being solids, and olein liquid, the consistency of a fat is dependent upon the proportions in which these substances are present. Stearin is a component of most animal fats, but never is found in vegetable fats. The chief constituent of animal fats is pal- mitin, and this occurs also in nearly all vegetable fats. Olein exists in both. Butyrin, caprin, caproin, and caprylin are glycerides of volatile fatty acids present m the fat of milk. Fats consist of carbon, hydrogen, and oxygen, and contain no nitro- gen. The hydrogen and oxygen are not present in the proportions in which they exist in water and in carbohydrates, the oxygen being de- ficient. As taken in food, fats are chiefly in the form of neutral substances, but more or less free fatty acid is always present, and in some foods which have been kept for a time, particularly in well-ripened cheese, fatty acids may be present in a free state in quite large proportion. The fats play an important part in the maintenance of animal heat and mechanical energy. When hard labor is being performed, an excess of fat is mstinctively taken. Carbohydrates. — The carbohydrates include the starches, sugars, and cellulose. The Starches, though presenting very different appearances under the microscope according to source, are of equal value as foods, and have the same composition. Starch is insoluble in water, but, heated ^ In this group the kyrines may be included. For the present we believe that it will be helpful to retain this term as defined, reserving the expression peptide for the sim- pler compounds of definite structure, such as dipeptides, etc. _ ^ The peptones are undoubtedly peptides oi- mixtures of peptides, the latter term being at present used to designate those of definite structure. COMPOSITION OF FOODS. 2'.) witli it to 72° C, tho oolls hvvcII mihI hiir-t, imd pi'.diK-.- ;i M.rt f.f iniicilajre, II(!;ik;(l vvilli diliilc; riiiiKirul luids, it is convrTt<-fl into <\cx- trosc;. Siil)j(!(i((ul to the: luilioii oC diustiisc, it \h cojivfrtcd into ninllo-c, Sturc.li is (oiiiid ulniost (!xc,liisiv(;ly in vc^ctiihlc^ (tells. It forms tin; chief [)iii't of tlu! s(!cds of the (icroiils iind of tlic; driod rcsidnc of cfrtiiin other VGj2;ctjil)lc pnxhicts, 8uch an potat^Kis. A forrji of st'irrh knrjwn as iininuU starch or <>;lycoir'!n is found in the liver ;ind Minscles, inifl al-o in sonu! of the molliiscii. Dttxlrin is an ;irti(icial |iro, c.'iiic sn^rar, A disjuiftharid. From snjjar cano, sorghnm, sugar maple, sugar beet, and some other vegetai^le stmrccs. In.sohibjp in strong nhtohol, does not I'ednee copper; not directly fcnncntaf)lc. Jioilcd with dilute acids, is (jonverted to invert sugar, a mixture of dextrose and Isevulose. 2. Dextrose, glucose, gra])o sugar. A. monosaccharid. Fonnd in many fruits and flowers. Formed from cane sugar, malto.-e, starch, and dextrin by boiling with dilute acids. In the presence of decr»m- posing proteids, splits into two molecules of lacti(r acid. Fcrmentwl with yeast, splits into alcohol and carbonic acid. 3. Maltose, malt sugar. A disacc^harid. (Two molecules of dex- trose.) Formed from starch by the action of diastase. 4. Lsevulose, fruit sugar. A monosaccharid. Found in honey and various fruits. Rotates the ray of polarized light to the left. Does not form crystals. Isomeric with dextrose. 5. Lactose, milk sugar. A disaecharid. (Dextrose and galactose.) Found only in milk. Behaves like dextrose. 6. Galactose. A monosaccharid. Formed from lactose by boiling with dilute mineral acids. 7. Inosite, muscle sugar, phaseomannite. Found in certain animal tissues, as the heart's muscle, and in certain plants, as peas, beans, and grapes. Has no rotatory power, does not reduce copper, and is not fer- mentable. It contains the benzene ring, and hence is not a true sugar. In the presence of decomposing j^roteids, it is converted into lactic and butyric acids. Cellulose. — Cellulose, while of value as a food for hcrbivora, has no nutritive value for man. It is converted to dextrose bv boiling^ with dilute sulphuric acid. Pectin. — Pectin is a substance not uncommonly classified as a car- bohydrate. It is composed of carbon, hydrogen, and oxygen, but its precise composition is unknown. It is found in various fleshy fruits and in roots, and is believed to be formed from pectose by the action of vegetable acids. It is known also as vegetable jelly. Pectose. — Pectose is an insoluble substance found in unripe fruits and roots : an eai'lier stage of pectin. The carbohydrates play an iiuportant part in the maintenance of heat and the production of force. They lessen the need of fat and form fatty tissue. Excessive ingestion interferes with the metamor- 24 FOODS. pilosis of nitroo-enous tissue, causes depositiou of fat in excess, and is likely to ])nKluco diucstivc disturbances. Deprivation for a time can be borne, provided the system receives sufficient fatty food, but not otherwise. Organic Acids. — The organic acids exist in foods cither in the free state or in Cf^nbination as salts. In the system they are converted to carbonates, which exercise a most imjiortant influence in controlling the alkalinity of the blood and other fluids. Dejirivation leads to a peculiar disturbance of the system resulting in scurvy. They include malic, acetic, lactic, oxalic, citric, and tartaric acids. INIalic acid is a constituent of apples, pears, and some other fruits. Acetic acid is the essential element of vinegar. Oxalic acid is found in considerable amounts in spinach, tomatoes, strawberries, sorrel, and rhubarb. Lactic acid is present in fresh meats and in milk. The twc^ most important acids are citric and tartaric. The former is found in oranges, lemons, limes, and otlier fruits ; the latter largely in grapes. Not all vegetables contain these acids, and, therefore, not all have antiscorbutic properties. Potatoes, cabbage, and roots are very effici- ent in this respect, while peas and beans are notable examples to the contrary. Inorganic Salts. — The important inorganic salts taken into the system with food include sodium and potassium chlorides, sodium, potassium, magnesium and calcium phosphates, and compounds of iron. The sulphates are of minor importance and are ingested in only small amounts. The sulphur essential to growth is taken into the system in combination in the proteids. The chlorides keep the globulins of the blood and other fluids of the body in solution, and are the source of the hydrochloric acid of the gastric juice. The phosphates are very essential to the gro^^i:h of bone and to the nervous system, and iron is needed for the haemoglobin of the blood. Deficiency of calcium and magnesium salts leads to rickets and other abnormal conditions. Section 2. ANIMAL FOODS: MEATS, FISH, EGGS, AND MEAT PRODUCTS. The foods of animal origin used by man include the flesh and various organs of the herbivora and swine, domestic and wild fowl, eggs, fish and shellfish, milk and milk products. The flesh of all carnivorous animals except fish is unpalatable, and, therefore, undesirable as food, though under stress of circumstances it may be borne. Thus, during the siege of Paris, about 5,000 cats and 1,200 dogs are said to have been eaten when the food supply had become so meagre that anythuig in the form of flesh was acceptable. In Germany, according to a com- munication of Consul-General Guenther to the State Department at Washington, under date of May 26, 1900, the statistical year-book shows that, on account of the high price of other meats, not only horses, but also dogs are much used as food. At Breslau, Chemnitz, Dresden, Leipzig, Zwickau, and other places, dogs are slaughtered extensively for this purpose and regularly inspected. ME A TF{. 26 Pirl» reports thai in S:ix(.iiy (liiiiiij_r 1H91, 21»r>; in 18!>r», .'JKH; in 1 «<)(;,,'{()!) ; ;inl yr-iirly, and in,sj)('(!ti()n hIiowcI (li.ii nnc in 202 was (ricliinons. Af^'ordinpj to Tcmpci;^ of 201 per fcnt., iind of I 17 killod dnrinn jli,. first linjf f)f the year IHOH, 2.04 pf;r cv.ul. were (()nn(l to l)(! (rifliiiKins. 'I'lu' trir-nt is caU-n rliiffly in tlie roasted state, hnt also, in many j)arls of Siixony, raw, hut lii^ldy sf^- soncd. The same animals arc eommonly eaten by the Chinese, and the (-anada lynx and (lie sl- teids, give flavor, but have li(tle value as foods. The earbohydnites play but an insignificant jnirt, being present chiefly as muscle sugar and to only a very small extent. All meat, however lean, confciins fat, some of which is visible and some indistinguishal)le from the musele fibres Ijy which it is surrounded. The visible fat varies widely in amount. Very fat beef may contain considerably more than a quarter of its weight of visible fiit, and fat pork meat more than a half, while chicken and veal contain comparatively little. The content of water varies veiy widely and in general may be said to be governed by the richness in fat, for, while the proteids are fairly constant in amonnt, the remainder is almost wholly water and fat, and the greater the amount of the one, the less the amount of the other. The less fat a meat contains, the less, therefore, its relative nutritive value. Digestibility. — ^Miile the amount of nutriment contained in meats chiefly determines their food value, the latter is to no inconsiderable extent dependent upon the ability of the alimentaiy tract to digest and absorb them. Gastric digestion is by no means to be accepted as a measure of the true digestibility of a food, and the same is tnie of the results of artificial laboratory experiments ; hence many of the accepted statements bearing on this subject, based upon the oft-quoted experi- ments on Alexis St. Martin and u]ion test-tube observations, may be wholly disregarded. Raw meat is digested more easily, but less completely, than that which has undergone the process of cooking, and roastetl meat is more completely digested than that which has been boiled. Fat meats, as beef and mutton, and especially pork, require more time for digestion than those which, like chicken and veal, contain but little fat. In general, it may be said that meats are assimilated more easily than v^e- table foods. Flavor. — The flavor of meats depends largely upon the nature and 1 Zeitsolirift fiir Fleisoli- and ililclihygieue, X., Xo. 1. - Ibidem, IX., Xo. 1. 26 FOODS. amounts of nitroo;enous extractives which they contain, and is greatly modified by the condition of the animal when killed, its age, sex, and the oliaracter of its food. The high flavor of birds and game is due to the richness in extractives, while in the case of meats deficient in these substances, as, for example, mutton and ]-)ork, the flavor is due largely to their contained fats. Most meats are improved in flavor by being kept for a time, during which, additional flavors, due to decompo- sition products similar to the extractives, are developed. The meat of young animals is flavored less highly than that of adults, and that of females than that of males, though in the case of the goose this condition is reversed, and in that of swine no difl'erence is ob- servable. Asexualization by spaying or castration produces a fatter, more tender, and bc>tter flavored meat. Thus, the flesh of oxen is far pre- ferable to that of bulls or cows, and that of capons and poulards to that of cocks and hens. Texture. — Whether a given meat is tough or tender depends upon the character of the walls of the muscle tubes and upon the amount of connective tissue present. The tube walls are thin and delicate, and the connective tissue is small in amount in the young and well-fed, but as the animal becomes older or is made to work, the tubes thicken and become hard, the connective tissue increases in amount, the fat may diminish, and the result is a coarser flesh. Very young animals have a very watery, gelatinous, and flavorless flesh. The texture of meat undergoes very considerable change after slaughter. When freshly slaughtered, it is tender and juicy, but as rigor mortis supervenes, it becomes hardened and tough. The stage of rigor is succeeded by the first stage of decomposition, during which lactic acid is formed. This acts upon the connective tissue and causes softening and tenderness, and as the process of decomposition proceeds Avithiu proper limits, increase of flavor is developed. Effects of Cooking'. — When meat is cooked, the connective tissue is softened, the bundles of fibrillse are loosened from each other, the albumin is coagulated, flavors are improved and new ones developed, parasites and micro-organisms are destroyed, and the whole mass is rendered more acceptable to the eye and palate. In the process of roasting or broiling, considerable shrinkage due to loss of water occurs. The heat to which the meat is subjected should be sufficiently intense to produce speedy coagulation of the exterior and prevent the meat juices from becoming dried up. In order that the surface shall not be burned, the meat must be basted from time to time with hot melted fat, which forms a protective coating. The heat employed should be less intense with large joints than with small ones, since before the lieat can pene- trate well into the interior, the outer parts will become burned. In 'boiling, the temperature of the water into which the meat is im- mersed varies according to the object sought. If a rich broth is de- sired, the meat is placed in cold water, which then is heated gradually. During the heating process, the soluble albumins together with a por- tion of the salts and the extractives are dissolved out. When the tem- MJ'JA TS. 27 poratiiro rcju'licH 1.T4° 1^\, IIk; ulhiirMiii hcfririH U) cojij.'iilaff, ;iri(] ;ih'>\'<; 1(50", IJk! coniKKil iv(! li.MHiK! Im (-Ii;! ii|j;c(I i,(> ^'clntin mikI (liy-olvt-d. Tin; Koliiiioii of (tcrl.'iiii ()(■ I lie (UMisI il iiciiis is jissislcd hy flic small amountH of Iii(;(.i(! acid loriiicd. if, oil fclio oth(T hand, if, i.s (Icsircd lo lia.Vf I lie jiiiff- and (lavofH rr- tiiiiu^d williiii IIk! mass, (lie meat lioiild Ix; iiliiii^n'd into boiling- \va(riHl<(!l., iiu!(liiiiii ("at ('Iiiu;l<, iiicliKliii^ HliDiildur. •A 1 <2 4 4 2 54.0 73.8 71.3 68.3 62.3 53.2 15.8 22.3 20.2 19.6 18.5 17.2 28.6 3.9 8.2 11.9 18.8 29,0 15,4 1495 580 IciiM 720 865 flit, 1135 very I'iiL .... 1555 Average 13 65.0 19.2 1005 Clmclv ril), vory lean loan 1 11 7 2 ~21 75.8 71.3 62.7 52.0 22.2 19,5 18,5 16.6 1.4 8.3 18.0 31.1 470 715 1105 fat 1620 Average 66.8 19.0 13.4 920 Jf'iank, very lean 3 3 5 3 2 70.7 67.8 60.2 54.2 34.7 25.9 20,8 18.9 17.1 14.0 3.3 11.3 21,0 28 4 51.8 1.2 1.0 0.9 0.8 0.7 620 865 niediuni fat lilt 1240 1515 very fat 2445 16 59.3 19.6 21.1 0.9 1255 3 12 32 6 3 70.8 67.0 60.6 54.7 49.7 24.6 19.7 18.5 17.5 17.8 3.7 12.7 20.2 27.6 32.3 1.3 1.0 1.0 0.9 0.9 615 900 medium fat fat 1190 1490 1695 Average 56 61.3 19.0 19.1 1.0 1155 Porterhonse steak 7 21 1 6 60.0 61.9 42.2 59.2 21.9 18.9 13.8 16.2 20.4 18.5 43,7 24.4 1.0 1.0 0.8 0.8 1270 1130 2100 Tenderloin 1330 Ribs, very lean 4 6 15 9 1 65.7 67.9 55.5 48.5 45.9 21.9 19.6 17.5 15.0 14.6 1,1 12.0 26.6 35.6 38.7 0.7 1.0 0.9 0.7 0.6 4,55 870 fat 1450 1780 very fat 1905 Average 35 •) 3 4 2 57.0 17.8 24.6 0.9 1370 73.7 69.0 63.9 51.5 20.8 20.2 19.3 17.2 5.0 10.5 16.7 31.3 1.0 1.0 0.9 0.8 600 820 medium fat fat 1065 1640 Average 11 64.8 19.4 15.5 0.9 1015 Konnd, very lean 6 31 18 5 2 73.6 70.0 65.5 60.4 55.9 22.6 21.3 20.3 ^ 19.5 18.2 2.8 7.9 13.6 19.5 26.2 1.3 1.1 1.1 1.0 0.8 540 730 medium fat fat 950 1185 very fat 1445 62 67.8 20.9 10.6 1.1 835 Round, second cut 2 69.8 20.4 8.6 1.1 740 Rump, very lean 4 4 10 5 1 71.2 65.7 5t>.7 47.1 40.2 23.0 20.9 17.4 16.8 15.0 5.1 13.7 25.5 35.7 44.3 1.2 1.0 0.9 0.8 0.8 645 965 1400 fat 1820 2150 24 57.9 18.7 23.1 0.9 1325 30 FOODS. BEEF.— Continued. Cut. Beef heart Kidney (carboliydrates 0.4) Liver (carboliydrates 1.5) . Marrow Tongue Lungs Suet Roast beef (cut not specified) Sirloin steak, baked .... Broiled tenderloin .... Round steak Canned corned beef .... Canned roast beef Canned whole tongue . . . Canned tripe Corned beef (all cuts) . . . Tongues, pickled Tripe (carbohydrates 0.2) el 2 'S o 1 .a < > ^ ^ ^ t, OS 2 62.6 16.0 20.4 1.0 1160 3 76.7 16.6 4.8 1.2 520 6 71.2 20.7 4.5 1.6 605 1 3.3 2.2 92.8 1.3 3955 3 70.8 18.9 9.2 1.0 740 1 79.7 16.4 3.2 1.0 440 9 13.7 4.7 81.8 0.3 3540 7 48.2 22.3 28.6 1.3 1620 1 63.7 23.9 10.2 1.4 875 6 54.8 23.5 20.4 1.2 1300 18 63.0 27.6 7.7 1.8 840 15 51.8 26.3 18.7 4.0 1280 4 58.9 25.9 14.8 1.3 1105 5 51.3 19.5 23.2 4.0 1340 2 74.6 16.8 8.5 0.5 670 10 53.6 15.6 26.2 4.9 1395 2 62.3 12.8 20.5 4.7 1105 4 86.5 11.7 1.2 0.3 270 PORK. Cut. Ham, fresh, lean medium fat fat vi.sible fat largely removed . Loin (chops), lean medium fat fat Tenderloin Shoulder Feet Head cheese Kidney Liver (carboliydrates 1.4) . . . Ham, smoked, lean medhim fat fat smoked, boiled Shoulder, smoked, medium fat . fat Salt pork, fat lean ends Bacon, smoked, lean medium fat eg 2' 10 5 3 1 19 4 11 19 8 3 2 1 3 14 4 2 3 2 7 4 2 17 60.0 53.9 38.7 64.5 60.3 52.0 41.8 66.5 51.2 50.7 43.3 77.8 71.4 53.5 40.3 27.9 51.3 45.0 26.5 7.9 19.9 31.8 18.8 Ph 25.0 15.3 12.4 19.2 20.3 16.6 14.5 18.9 13.3 8.3 19.5 15.5 21.3 19.8 16.3 14.8 20.2 15.9 15.1 1.9 8.4 15.5 9.9 14.4 28.9 50.0 16.2 19.0 30.1 44.4 13.0 34.2 17.4 33.8 4.8 4.5 20.8 38.8 52.3 22.4 32.5 63.6 86.2 67.1 42.6 67.4 1.3 0.8 0.7 0.9 1.0 1.0 0.7 1.0 0.8 0.4 3.3 1.2 1.4 5.5 4.8 3.7 6.1 6.7 5.2 3.9 5.7 11.0 4.4 1075 1505 2345 1040 1180 1580 2145 900 1690 1090 1790 490 615 1245 1940 2485 1320 1665 2545 3670 2985 2085 3030 MI'JA TS VEAL. 31 Cut. 5 7 9 10 'A 72.1 (56.0 73.r, 70.0 70.7 7;i.3 69.0 61.6 73.2 75.8 73.0 'S 1 21.7 19.6 21.3 20.2 20.3 20.4 19.9 18.7 16.8 16.9 19.0 i JS 5.fi 14.0 4.1 9.0 7.7 5.6 10.8 18.9 9.6 6.4 5.3 1,1 1.0 1.2 1.2 1.1 1.2 1.0 1.0 1.0 1.3 1.3 640 955 lA'K, li^a.i . 670 755 705 Loin, Iwui iiKMliiiin (at fj,t 6 2 1 2 2 615 825 1145 Heart 720 585 Liver 575 MUTTON. Cut. Hind leg, lean medium fat fat Loin, medium fat without kidney and tallow fat without kidney and tallow .... very fat without kidney and tallow . . Fore quarter Hind quarter Eoast leg, cooked Kidney Liver (carbohydrates 5.0) <.-. O tn 1 '53 s i < 'A< Ph 3 67.4 19.8 12.4 1.1 11 62.8 18.5 18.0 1.0 1 .55.0 17.3 27.1 0.9 13 50.2 16.0 33.1 0.8 3 43.3 14.7 41.7 0.8 1 30.8 10.6 58.7 0.5 10 52.9 15.6 30.9 0.9 10 54.8 16.7 28.1 0.8 2 50.9 25.0 22.6 1.2 1 69.5 16.9 12.6 0.9 2 61.2 23.1 9.0 1.7 a* t. s 890 1105 1465 1695 2035 2675 1595 1495 1420 845 905 LAMB. Cut. o — — t. a •s " = S o o Pui < o 63.9 19.2 16.0 1.1 1055 54.6 18.3 27.4 0.9 1495 ' 1 51.8 17.6 30.1 0.9 1595 53.1 18.7 28.3 1.0 1540 55.1 18.3 25.8 1.0 1430 60.9 19.6 19.1 1.0 1170 47.6 21.7 29.9 1.3 1665 67.1 19.7 12.7 0.8 900 Hind leg, medium fat .... fiit very fat Loin, without kidney and tallow Fore quarter Hind quarter Broiled chops Koast leg 32 FOODS. POULTRY. Cut. Broiler chickens Fowls . • Young goose Turkey Chicken liver (carboiiydrates 2.4) Goose liver si 3 26 1 3 1 1 74.8 63.7 46.7 55.5 Gl).3 73.8 21.5 19.3 1G.3 21.1 22.4 ly.G 2.5 16.3 36.2 22.9 4.2 5.8 1.1 1.0 0.8 1.0 1.7 1.0 Jj tH aj 505 1045 1830 1360 640 610 Horse Meat. — The nicau of twelve analyses of horse meat as given Water 74.27 Proteids 21.71 Fat 2.55 Ash 1.01 The objection to the use of horseflesh as food is very largely senti- mental. It has not the pleasant flavor of beef, to which we are accus- tomed, but when eaten in ignorance of its true character, it makes no unpleasant impression. Its use is increasing steadily in Eurojie, and is finding favor in America. In Paris, during 1898, 21,667 horses, 52 mules, and 310 donkeys were slaughtered for food, and of these but 734 horses, 1 mule, and 7 donkeys were condemned as unsalable. The meat was disposed of in 193 shops, where the best cuts brought about a franc (19.3 cents), and the inferior parts 10 centimes (2 cents) per pound. In 1910^ the annual amount of horse and mule meat con- sumed in Paris had increased threefold, reaching the sum of 29,700,000 pounds and representing about 61,000 animals. During 1896, 822 horses and mules were slaughtered in Strass- burg, and in 1898 the number rose to 1099. In Vienna, where the sale of the meat was permitted first in 1854, there were slaughtered, in 1899, 25,646 horses and 58 donkeys. In the whole of Prussia, there were slaughtered, in 1897, at 367 abattoirs, 58,484 horses, and in the following year tlie number rose to 63,531. In Frankfort, where, in 1847, the first horse-meat dinner ever given occurred, about a thou- sand horses are slaughtered annually, at a special abattoir. In the United States, during 1899, 3,232 horses were slaughtered and offi- cially inspected with other food animals. It is said that, unless the fat of some other animal or some starchy food is eaten with it, horse meat may cause diarrhoea. Whatever causes tliis disturbance is soluble in water, and may thus be removed partially when the meat is boiled. From water in which horse-meat had been boiled, E. Pfliiger^ separated jecorin, lecithin, and (probably) neurin. He recommends the addition of about 25 grams of beef or 1 Zusammensetzung der nienschlichen Nahrangs- und Genussmittel, Berlin, 1882. ■■' U. S. Daily Consiilar and Trade Keports, Nov. 1, 1910, p. 420. 3 Arciiiv fiir die gesanimte Physiologie, 1900, Bd, 80, p. 111. MICATS. 33 mutton ki(lii((y-f;it to cucJi kilofj^rarn of tlio ni(;;it when !i minw is if) b(! iiiiwlc, iiiid that, in \vliiit(!V(!r I'orrn is i.s coiisiuncd, it Im; .s(;rvc(l with a ("at ^ra,vy. Meat Preparations. — Meat Extracts. — These an- f)r(;}>aratif)nH whiiih arc; ,sii|)|»os('resent thi; extruefives and not llie sul)staii(!es which detcrniiiK; thi; true food value. In j)oint of fact, so far as \\w\r nntriliv(! piopertics arc concerned, it ha.s bw;n shown thai animals will die more (|ui(!kly of Btarvation when fed cx- chisivc^ly u])on these; slimniatinti; |>re|)arationH than when entirely fle- privcd of food. They arc, however, of considerable value in fheir proper place, paiticularly in conditions of great fatigue and exhaustion. Meat Powder. — Meat may easily be treated so as to retain all of its nutriment and yet have a very much diminished volume. The lean ])arts are cut into small sti'ips, dipped for a few mirnites into very hot fat (fried), drained, and tlu^n slowly dried in an oven. When com- pletely dry, they are ground in an ordinary s])ice mill or coffee mill to a fine powder, ^vdlich keeps well, has an agreeable tiiste and a ])leasant odor, is digested easily, and may be used in a great many different ways. Sausages. — Sausage is understood generally to mean an article of food consisting chiefly of finely chopped meat, maiidy pork and beef, with or without the addition of a small amount of meal, highly sea- soned with spices, herbs, and other flavorings, and stuffed into casings made from cleaned and prepared intestines. Their nutritive value is, therefore, about the same as that of average meat. As may be suj)posed, the best cuts of meat are not used in their manufacture, but only such parts as cannot be disposed of in pieces of fair size and of attractive appearance. But there are sausages and sausages. There are those made from meat of good quality and others from materials which would not be salable in any other form. Many of the so-called Frankforters, sold at very low rates, and the cheap Bolognas are said to consist largely of horse meat, immature veal, and the flesh of cows that are no longer in condition to produce milk. Certain it is that a not inconsiderable number of persons g-ain a fair livelihood by going about in the country l)uving up newly born calves and decrepit cows, tuberculous and othenvise, and horses, and that these animals are not taken to comfortable stables and inviting pastures, but to small slaughtering establishments, the output of which is not very largely butchers' meat. To the cheap grades of sausages the saying of Jean Paul, " Only a god can eat sausage, for only such can know of what it is made," applies very aptly. Even sausages made from pork, especially those which have undergone a process of cooking before being stuffed, are not always beyond suspicion, for the triehiuous pork condemned by government inspectors at public abat- toirs is neither destroyed nor converted into fertilizers, but is allowed to be sold after being subjected to a heat sufficient to kill the parasites ; and cooked pork is not commonlv to be found on sale as such. 3 34 FOODS. Horse meat is said to combine two advantages in the preparation of sausage : it is inexpensive, and it lends a firmness which increases as the sausage is boiled. A number of chemical processes have been pro- posed for its detection, and among them the following : Dr. Notel * covers coarsely chopped horsemeat with a 0.1 per cent, solution of sodium hydroxide, lets the mixture stand 3 hours at 37° C, and then separates the liquid through cheese cloth. The liquid is injected, in doses of 8 to 10 cc., subeutaneously into a rabbit at intervals of 2 or 3 days until 10 or 12 injections have been given. Six days after the last injection, the animal is bled and its serum serves as a reagent. The suspected food is chopjied finely, covered with 0.1 per cent, sodium hydroxide, allowed to stand 2 hours in a Avarm room, and filtered. A few drops of the filtrate are mixed in a test-tube with about an equal amount of the serum, and other tubes containing filtrate alone are used as controls. The tubes are incubated at 37° C, and if the suspected article contains horsemeat, the tubes containing the serum will become cloudy in from 10 to 40 minutes. A number of tests which depend upon the reaction of iodine with glycogen, which is a normal constituent of horsemeat, are criticised by Niebel ^ as uncertain, on account of the presence of glycogen in liver, meat extract, and very young veal. A recent and more reliable test for horse meat has become possible through the studies of Ehrlich and his pupils ^ * ^ ^ upon immunity. If, for example, a rabbit be inoculated with the blood serum of a horse or other alien animal, the serum of the rabbit acquires, after a time, a property, by reason of which a specific precipitation occurs when an extract of horse meat is mixed with it. This test method has been further developed by Wassermann and his pupils, and can be applied with success to other kinds of meat. The differentiation of meat of closely allied species, however, such as that of sheep and goats, is said to be at times quite difficult. In the manufacture of all grades of sausage, scrupulous care should be observed to secure cleanliness of the casings, which require more thorough treatment than the mere passage of water through them. Dr. Schilling^ reports the examination of prepared intestines which yielded 5 grams of excrement per meter. Owing to the occurrence of a gray color, which is said by Meyer* to 1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXXIX., p. 373. 2 Zeitschrift fur Fleish- und Milchhygiene, 1895, p. 86. _ 3 Schiitze, A., Ueber weitere Anwendungen der Pracipitine. (Deutsch. med. Woch., 1902, No. 45, p. 804.) * Wassermann, A., u. Schiitze, A., Ueber die Entwickelung der biologischen Methode zur Unterscheidung von menschlichem und tierschem Eiweiss niittels Pracipitine. (Ibid., 1902, No. 27, p. 483. ) 5 Wassermann, A., Ueber Agglutinine und Priicipitine. (Zeits. f. Hyg., etc., Bd. 42, 1903, 2, p. 267. ) 6 Ulilenhuth, Die Unterscheidung des Fleisches verschiedener Tiere mit Hilfe spezifische Sera und die praktische Anwendung der Methode in der Fleischbeschau. (Deutsch. Med. Woch., 1901, No. 45, p. 780.) ^ Deutsche medicinische Wochenschrift, 1900, p. 602. 8 Chemiker Zeitung, 1900, p. 3. FISH. 35 JH' (liK! U) tlio paH.sa^o of Halt by dilTiiHion from \\\c ronfxaits to tho (iasiiiff;, wlii(!li is rich in watcir iiiul poor in salt, llic. coiiiiiicroial value of c(!rt,ain vari(!tics of HauHa|ij(! is impaired, ;iiir cannot Ik; precij)itatcd as a lake. Accordinj^ to J. Ilaldane,* the red color of cooked sidted nncata is due to thoi)rcsence of N()-h:cmochromogen produced l)y the decomjiosi- tion of NO-hficniot2;Iol)in, which is formed by the; action of a nitrit<; on the N()-hicmoehronioo;(!n in tlu; absence of oxygen and presence of re- (lucino; agcMits. Tlu; nitrite is formed by reduction, within the raw meat, of the niter used in salting. Certain of the artificial sausage colors, as "Orange II.," the sodium salt of /?-naphtli()laz()benzcne, arc extracted easily with acidulated water, and will dye woolen fibers immersed therein. FISH. In the ordinary sense of the word, fish includes, in addition to the varieties of fish in its narrow sense, mollusks (clams, oysters, mussels, etc.) and crustaceans (lobsters, crabs, crawfish, and shrimps). Many prejudices have existed from the earliest times, and to a cer- tain extent still exist, against the use of fish in the diet. The ancient belief that a fish diet is a common cause of leprosy still obtains to a certain extent, even among enlightened people, in s})ite of all scientific evidence to the contrary. Thus, Mr. Jonathan Hutchinson^ main- tiiins that this disease is so caused, especially if the fish is poorly cooked or partially decomposed. He asserts that the disease prevails near the sea and is disappeariug before the advance of agriculture ; but op- posed to this is the fact that, in the interior of India, the disease is very common among people whose religion forbids the use of fish, and who cannot obtain it even if it w-ere desired. Some varieties of fish cannot be eaten, because of their inherent poisonous properties. But few of these are, however, found north of the tropics. Some of them are always poisonous, and others only at certain times ; and in some cases, individuals of certain species may be and others may not be noxious. Some varieties of fish are the hosts of parasites, some of which are injurious to man, but unless eaten in the raw state they are not likely to produce harm. There is a belief that fish is particularly valuable as a brain fotKl, on account of the supposed high percentage of phosphorus that it contains. The amount of phosphorus is, however, so far as is known, no higher in fish than in meat and, moreover, this element is no more essential to the brain and nervous system than any others which are present. 1 Journal of Hyariene. 1901, Vol. I., p. 115. ' Archives of Surgery, April, 1S99. 36 FOODS. If there were any truth in this common belief, we should expect naturally to find men of commandine; intellect among those whose diet consists mainly of fish, but, as is well known, such jicople are of a low order of intelligence, though not by reason of their diet. In spite of the large amount of nutriment contained, fish has not the same satisfying properties that belong to meats, but it is an exceed- ingly valuable food, and in many parts of northern countries is the principal animal food. The flavor of fish is infiucnced greatly by the nature of the food supply and by the content of fat. Generally speak- ing, salt-water fish from deep water, where the current is strong, are better than those from shallow, warm, and quiet Avater, and both salt- water and fresh-water fish taken from rocky and sandy bottoms are preferred to those from muddy bottoms. Condition is dependent upon a variety of circumstances. Some fish are regarded most highly during their spawning season (shad and smelts), while others are looked upon with disfavor at this period. Fish caught by the gills in gill nets die slowly, but decompose rapidly, and such are of inferior flavor and value. Fish taken from the water alive and killed at once remain firm and retain their flavor longer than those allowed to die slowly. Digestibility. — So far as is known, the digestibility of fish and meat is about equal, but, as is true of meats, diifereut varieties of fish are diflerently digestible. Thus, those which contain the greatest per- centages of fat, as salmon, eels, and mackerel, are the most difficult of digestion. The processes of drying, smoking, salting, and pickling lessen digestibility, and fish so treated are, in consequence, less suited to the needs of invalids and dyspeptics. The mollusks are regarded generally as most digestible, Avhile the crustaceans are believed to tax the digestive powers much more than any other animal food. Many persons are unable to digest them in any form, and others who suifer no inconvenience, so far as digestion is concerned, are obliged to prac- tise self-denial, because of idiosyncrasy, which manifests itself in dis- tressing eruptive disorders of the skin, dizziness, and other nervous symptoms. Lobster and crabs are much alike, but the former is less likelv to disagree. The claws of the lobster are more tender and deli- cate than the tail, which is firmer and much closer grained. Shrimps are rated generally as more difficult of digestion than lobsters and crabs, but with many they are borne more easily. The mollusks are more digestible in the raw state than when cooked. The comparatively tough part of the oyster, the adductor muscle, is very trying to some persons, and for such it is best removed and rejected. Keeping- Qualities. — Fish flesh differs very greatly from meats in keeping qualities. While the latter are improved up to a certain point by hanging, fish should be eaten while fairly fresh, since decomposition sets in very quickly. Some varieties, as halibut, cod, haddock, and turbot, may be kept a week or more when properly cared for, while others begin to deteriorate almost immediately. So long as the flesh /'7.S7/. 37 isfirrn iiiid stilT, all fisli Ih edible, but, wlien it, is eriislied readily by ^<'n- tle jtressiire bcii-vvcten tlie (iiifi;ers, if is misoiind and .should be rejcefed. MoIIusUh and enislaeeaiis deeniiipose very (|iiielerlmen(, Stations: Food Materia i.h. Fresh Fish. Bass, striped Blackfisli mueiish Buiiklo fish iiutter-fish Catfisli Ciscoe Cod, whole (Jod, sections disk Eels, salt water Flounder . . Haddock Hake Halibut Herring Kingfish Lamprey Mackerel Mullet Muskellunge Perch, white Perch, pike (wall-eyed pike) . . . Perch, yellow Pickerel, pike Pike, gray Pollock Pompano Porgy Red grouper Red snapper Salmon, whole Salmon, landlocked, whole, spent . Salmon, California, anterior sections Shad Sheepshead Skate, lobe of body Smelt ." Spanish mackerel Sturgeon, anterior sections .... Tomcod Trout, brook Trout, salmon or lake Turbot Weakfish Whitefish Water, Per ct. Protein N X G.25 Fat. Ash. Per ct. Per ct. Per ct. 77.7 18.6 2.8 1.2 70.1 18.7 1.3 1.1 78.5 19.4 1.2 1.3 78.() 18.0 2.3 1.2 70.0 18.0 11.0 1.2 04. 1 14.4 20.6 .9 74.0 18.5 6.8 1.1 82.6 16.5 .4 1.2 82.5 16.7 .3 .9 82.0 17.0 2 .9 71.6 18.6 9.1 1.0 84.2 14.2 .6 1.3 81.7 17.2 .3 1.2 83.1 15.4 .7 1.0 75.4 18.6 5.2 1.0 72.5 10.5 7.1 1.5 79.2 18.9 .9 1.2 71.1 15.0 13.3 .7 73.4 18.7 7.1 1.2 74.9 19.5 4.6 1.2 76.3 20.2 2.5 1.6 75.7 19.3 4.0 1.2 79.7 18.6 .5 1.4 79.3 18.7 .8 1.2 79.8 18.7 .5 1.1 80.8 17.9 .8 1.1 76.0 21.6 .8 1.5 72.8 18.8 7.5 1.0 75.0 18.6 5.1 1.4 79.5 19.3 .6 1.1 78.5 19.7 1.0 1.3 64.6 22.0 12.8 1.4 77.7 17.8 3.3 1.2 63.6 17.8 17.8 1.1 1 70.6 18.8 9.5 1.3 75.6 20.1 3.7 1.2 82.2 18.2 1.4 1.1 79.2 17.6 1.8 1.7 68.1 21.5 9.4 1.5 78.7 18.1 1.9 1.4 81.5 17.2 .4 1.0 77.8 19.2 2.1 1.2 70.8 17.8 10.3 1.2 71.4 14.8 14.4 1.3 79.0 17.8 2.4 1.2 69.8 22.9 6.5 1.6 Fael value per pound. Calor. 465 405 410 430 800 1135 630 325 325 190 730 290 335 315 565 660 390 840 645 555 480 530 365 380 370 365 435 665 560 385 410 950 470 1080 750 530 400 405 795 415 335 445 765 885 430 700 38 FOODS. Food Materials. Fish, Preserved and Canned. Cod, salt Cod, salt, "boneless" Haililock, smoked Halibut, smoked Herring, smoked Lamprey, canned Mackerel, salt Mackerel, salt, canned in oil . . Mackerel, salt, dressed Minogy, pickled, canned .... Salmon, canned Sardines, canned Sturgeon, dried, Russia .... Trout, brook Tunney, canned in oil, Russia . Shellfish, Fi-esh and Canned. Clams, long, in shell Clam.s, long, canned Clams, round, in shell Clams, round, canned Crabs, hard shell Crabs, canned Crayfish, abdomen Lobster Lobster, canned Mussels, in shell Oystei-s, in shell Oysters, canned Shrimp, canned Terrapin Turtle, green Water. Protein N X 6.25. Fat. Ash. Per ct. Per ct. Per ct. Per ct. 53.5 25.4 .3 24.7 55.0 27.3 .3 19.0 72.5 23.3 .2 3.6 49.4 20.7 15.0 15.0 34.6 36.9 15.8 13.2 63.3 16.9 12.2 4.0 42.2 21.1 22.6 13.2 58.3 25.4 14.1 4.1 43.4 17.3 26.4 12.9 56.5 22.0 18.6 3.0 63.5 21.8 12.1 2.6 52.3 23.0 19.7 5.6 50.6 31.8 9.6 7.6 68.4 22.3 6.1 3.7 51.3 23.8 20.0 4.3 85.8 8.6 1.0 2.6 84.5 9.0 1.3 2.3 86.2 6.5 .4 2.7 82.9 10.5 .8 2.8 77.1 16.6 2.0 3.1 80.0 15.8 L5 2.0 8L2 16.0 .5 1.3 79.2 16.4 1.8 2.2 77.8 18.1 1.1 2.5 84.2 8.7 1.1 1.9 86.9 6.2 1.2 2.0 83.4 8.8 2.4 1.5 70.8 25.4 1.0 2.6 74.5 21.2 3.5 1.0 79.8 19.8 .5 1.2 Fuel value per pound. Calor. 410 490 440 1020 1355 895 1345 1065 1435 1195 915 1260 995 670 1300 240 275 215 285 415 370 340 390 390 285 235 335 520 545 390 Composition. — In proteids, fish rank nearly as high as meats, but they are very much poorer in fat, only a few varieties yielding over 10 per cent. These include salmon, turbot, lamprey eels, eels, butterfish, lake trout, and herring, and are followed by shad and Spanish mack- erel, with over 9 per cent. The great majority of species contain less than 5 per cent., and many of the commoner kinds even less than 1 per cent. In fact, most fish flesh yields more mineral matter than fat. Shellfish are fairly rich in proteids and contain notable amounts of carbohydrates, but they are very poor in fat. Meat and Fish and Parasitic Disease. Man is often the host of parasites through ingestion of infested meat and fish. Of these, the most common is the tapeworm, of which at least ten species are known, though only three have been demonstrated as having any connection with food. These are Taenia saginata (T. mediocanellata) due to measly beef. Taenia solium to measly pork, and Bothriocephalus latus to infested sturgeon, pike, perch, and salmon. MI<:AT AND FISH AND rAllASITK! D/.SJ-JA.SK .'iO Tli(! hdU'.r iH very run; in tlii.s coiiiifry, tlioii^li not iiru;r)mrnon .'iKtii^^ tli(! liiiJlJt!. OCIIm- Iav'^c miirilxir of worrriH \vlii<'li iii(i.~t fisli, tins is tlir- only on(! ljhr,id fever. In a short time, a train of symptoms quite unlike those of that disease appeared, the most marked one being very acute pain involving the entire muscular system, and intensified on attempting to naove. On account of the agony induced, extension of the arms and legs ^vas quite impossible. Pneumonia supervened, and in a few days the victim died. The autopsy revealed the parasite in vast numl)ers in the muscles, and this led to further investigation, which showed that, four days before the first symptoms of illness a])])cared, she had eaten freshly killed pork. Some of this was secured in the form of ham and sausage, and examination demonstrated the presence of the parasite 1 lie first extensive outbreak which caused the disease to be looked upon as one of great importance occurred in Prussia in 1863 when more tlian 20 persons died within a month after a dinner in whicli 103 had participated, and at which smoked sausages made from an infested pi^ghad been served. The parasites were discovered in the muscles of those who died and in the sausages that remained. Since that time. It has been customary in most large slaughtering establishments to examine pork for evidence of the parasite, before passing it as fit for food. Lut examination is not always a safeguard, even in countries where it is observed most carefully. In Germany, for instance, where all meats are supposed to be examined with scrupulous care, particu- larly those from the United States, the disease is viry commom In 1883, on account of the alleged dangers which lurked in Ameri- can meats, importation was interdicted for a time, but in the succeed- ing 15 years there were in Prussia alone 3,003 cases and 207 deaths not one of which could be traced to American meat either salted' FLA'I E I ru: 1 ^.«*, "«i Free Trichina. :< 38. Trichinse in Pig Muscle. X 75. MJ'JAT AND FISH AND J'ARASJ'J'KJ DISEASE. 41 j)ickl<^j)iHt« of the IT. S. I)e|)artmcnt of A^nicMiHun; in U ,i\r/.) <,f tlie 2,227,710 hogs examined. It is j)r()hahle, as stjitcd hy ('harles W. Sliles,' who eon<(;t<(l ahout 900 re[)orted eases wlii<^li had occurred in tliis count ry rhiriii}: the .'^(5 years ]H()()-l sur- reptitiously and exiteu.^ Trichinosis bears certain resemblances to typhoid fever and to acute tu- berculosis, but in addition is accompanied by oedema and intense pain. It arises from eating the infested meat in a raw or not well cooked condition. The trichinae are killed by exposure to 155° F., if they are not encapsulated; otherwise by a temperature of 158° to 160°. They are not affected by intense cold, putrefactive processes, nor ordinary smoking, but are killed by long pickling. The first symptoms appear in a few days after ingestion, and indi- cate irritation of the alimentary canal. These are followed by feV)rile symptoms and intense muscular pains. Death may occur within a few weeks. In case of recovery, the parasites become encysted, and then are incapable of producing further injury to their host. The manner in which they jn'oduce their effects is as follows : When the infested meat reaches the stomach, the digestive juices dissolve the capsules, and the parasites thus are left in a free state. In the intes- tine, they find conditions flivorable to growth, and in a few days' time they grow so large that they can be seen with the naked eye and appear like fine threads. 1 Philadelphia Medical Journal, June 1, 1901. ' Journal of Medical Research, July, 1901, p. 64. 3 For an account of such a case consult Zeitschrift fiir Fleisch- und MilchliTgiene, 1897, VU., p. 104. 42 FOODS. The female parasites when fully mature begin to produce young, each to the extent of upward of 500. These begin at once a migra- tion through the walls of the intestine and find their way to all parts of the body, and it is during this stage that the fever and intense pain are caused. W. G. Thompson,^ as a result of observation upon 52 cases in his personal practice, believes that the diif'erential diagnosis can easily be made if the following points are observed : 1. Acute onset usually with vomiting and abdominal cramps. 2. A high grade of eosinophilia invariably present ; usually above 30 per cent, and frequently much higher — even above 80 per cent. 3. A high grade of temperature, often reaching 104° F. or more, and lasting, in lessening degree, for two to six weeks. 4. Puffiuess of the eyelids and face, with pains in the eyes occurring in one-fourth of the cases. 5. Dyspnoea and diaphragmatic breathing occurring without cyanosis in about one-fourth of the cases. 6. The generalized muscle pains, cramps, soreness, and prostration, causing sometmes deceptive apparent immobility. 7. The sudden occurrence of symmetrical circumscribed corneal hemorrhages in a patient whose bloodvessels are not degenerated should give rise to a suspicion of trichinosis. The examination of the blood for an increased number of eosino- philes is of the greatest importance. Furthermore, if a small piece of muscle be excised under local anesthesia, the parasites can be fre- quently discerned under low powers of the microscope. It is not, however, always possible to secure the consent of the patient to this minor operation. For this reason an observation, made recently by Herrick and Janeway,^ is of great interest. These investigators, fol- lowing a method devised by Stiiubli,^ in which method a small amount of blood is laked with 3 per cent, acetic acid, were able to detect the parasite in the circulating blood. Cross^ also was able to demonstrate the trichinella in the blood taken from an ordinary ear puncture. The patient was taken sick on August 17, 1909. On August 24th the diagnosis of trichinosis was made, largely because of a differential count, showing that 20 per cent, of the white corpuscles were eosinophiles. Excision of a piece of muscle could not be done, and on August 25th a blood examination was made. One cubic centimeter of blood was squeezed from the ear and laked with 12 cubic centimeters of 3 per cent, acetic acid. The sediment obtained by centrifuge was examined under low powers of the micro- scope. One trichinella was easily found and two others were seen with less distinctness. 1 American Journal of Medical Sciences, August, 1910. ^ Archives of Internal Medicine, 1909, April, p. 263. 3 Stiiubli, Klin, und exper. Untei-sucb. iiber Trichinosis. Verhandlung. des Kon- gre.ss f. Klin. Med. Wiesbaden, 1905, 354. Beitrag zum Nachweis von Parasiten in Blut. Miinch. Med. Woch., 1908, Iv., 2601. ^ Archives of Internal Medicine, Sept., 1910. HLA'i'h II Trichinae in Huinan Muscle, showing Thickened Capsule. X 78. Triehinag iu Human Muscle, x 75. MI'JAT AND FISH AND I'AJIASITK! DISIIASE. 43 In rki(! I., V\\!^. "A, .'111(1 I'hiff! II., V'lii;. 1, uro ko(;ii fliiri Hections of mu8olo from a linrMiUi subject, KJiowing the worm coiled up and the thickoiio'l <• said, is used to inchid(! a large number of abnc^rmal ecmdition.s, but which, in its strict apj)lication, means a parasitic disea-se of the liver, \h believed by many to be of sufTicient im|)ortance to warrant the con- denmation ofllie fh^sh of the animal, but the scientific evi willioiit evil (id'dcls. A siinilar iiiitniinily li:is often Iccn noticed ulU.T the c()iiHiiinj)tJoii of" \\h'. (•;i,rejisH(!S of :inlin;ils moist ;ind llahhy. It i- liilie\cd ihnt the nnsit Is cdil)l(!, if it^ poSHCHKCS a norinal a|)|»ear;Miee. The nuiil in rinderpest iindcrj^oes no niai'ked (tliannc in appearance, cxc(;|)liii^ in advanced cas(\s, when it, is dark in color and llahhy and of" disa^reeal)l(! txior. Jn or per cent. iU'(! tnbercnlons. In Mn.ssuclniHCittH, tlio.se in .'i yK).sition to Ix; best informed Kliite that, ;unon^ covvh, the (lise;is(! in mnr-h mon; frecpjcnt th:in in New York, but tluit it is rarely to be CoiuhI in <;i1v(jh, Ht(M;rH, and ox(!n. In Peimsylvainn, tlu! Slat(! velerinarian believes that not ovi'Y 2 per cent, of all cattle an; tnbercnlons. At the larp- abaltx»irs of this country, ubont 1 in 2,000 cattle is f(»nnd to be tnbercnlons. Dnr- \w\r the two years (nided.Innc oO, 1801), «,H;}|,027 cattle were inspected by tlu; Federal atithoriti('s, and 7,015, or 1 in 1,259, were condemned on account of tuberculosis. During 1000, of 4,801,100 inspected, 5,27!), or 1 in 021, were condemiuid. Of 2.'>,'>.')0,)S84 hogs insj)ectcd, 5,440, or 1 in 4,200 were sufficiently affected to warrant wndemnaticm of at least a part of the carcass. Some Rksui.ts of Tuiieucumn Tksts of Cattle hy State and Fedekai- f )fkker« WITH TlUiEKCULlN FuErAUED IJY THE lit KFAU OF AnIMAL LvjUSTItY, 1898, TO July 31, 1908, Inclusive.^ states. California . . Connecticut . Illinois . . . Indiana • . . Iowa .... Maine .... Massachusetts Michigan . . . Minnesota . . Missouri . . . New Jersey . New York . . North Carolina Ohio .... Oregon . . . Vermont . . . Washington . Wisconsin . • Number of cattle tested. 9,618 6,080 7,120 2,935 4,020 3,264 86,223 2,155 60,733 1,680 3,293 4,034 1,207 2,933 1,466 162,570 2,779 32,297 Number reacting. 1,112 852 790 246 778 149 11,853 351 3,031 133 828 565 208 425 351 10,628 455 3,477 Percentage reacting. 11.56 14.01 11.09 8.38 193.5 4.56 13.75 16.29 4.99 7.92 2.5.14 14.00 17.23 14.49 23.94 6.54 16.37 10.77 The organs iuvolved most frequently in tuberculosis of animals are the liver,\mgs, kidneys, bram, and udder. The muscles are aflected very rarely, although the bacilli have been found in the expressed juice. At what stage of the disease meat becomes unfit for food, is a ques- tion over which there is much cimtroversy. Extremists on the one side believe in condemning the entire carcass on the slightest evidence of disease in any part thereof, while those on the other side maintain that the entire animal may be used as food without injur}-. In Eng- 1 Circular No. 8, June, 1910, INIichigan Agricultural College Experiment Station, Division of Bacteriology and Hygiene, page 61. 48 FOODS. land, the practice is to condemn any carcass in which the disease has made such extensive progress that the flesh has become dete- riorated. The Royal Commission on Tuberculosis^ concluded that meat from tuberculous animals may be consumed with hnpuuity, if sufficient discriuiiuation aud care are exercised in slaughtcrinji: and dressino^. Every part containing tubercles should be removed and destroyed, " and ' the whole carcass itself in advanced or general tuberculosis. The Frcuch law excludes carcasses with generalized tuberculosis and those in which local lesions have involved the greater i)art of an organ. The same is true in Austria, In Prussia, the meat is held to be unfit for food if the animal has begun to show emaciation, but is passed as fit for human consumption if the disease occurs in only one organ, and in general, if the animal is well nourished. In Belgium, the law of September 30, 1895, permits the sale of meat of tuberculous animals after sterilization. In the United States the following rules are given by the Bureau of Animal Industry, in reference to carcasses affected with tuberculosis : ^ Section 13. — Paragraph 1. — The following principles are declared for guidance in passing on carcasses affected Avith tuberculosis : Principle A. — The fundamental thought is that meat should not be used for food if it contains tubercle bacilli, if there is a reasonable possibility that it may contain tubercle bacilli, or if it is impregnated with toxic substances of tuberculosis or associated septic infections. Principle B. — On the other hand, if the lesions are localized and not numerous, if there is no evidence of distribution of tubercle bacilli through the blood, or by other means, to the muscles or to parts that may be eaten with the muscles, aud if the animal is well nourished and in good condition, there is no proof, or even reason to suspect, that the flesh is unwholesome. Principle C. — Evidences of generalized tuberculosis are to be sought in such distribution and number of tuberculous lesions as can be explained only upon the supposition of the entrance of tubercle bacilli in considerable number into the systemic circulation. Significant of such generalization are the presence of numerous uniformly distributed tubercles throughout both lungs, also tubercles in the spleen, kidneys, bones, joints, and sexual glands, and in the lymphatic glands con- nected with these organs and parts, or in the splenic, renal, prescap- ular, popliteal, and inguinal glands, when several of these organs and parts are coincidentally affected. Principle D. — By localized tuberculosis is understood tuberculosis lim- ited to a single or several parts of organs of the body without evidence of recent invasion of numerous bacilli into the systemic circulation. Paragraph 2. — The following rules shall govern the disposal of tuberculous meat : 1 The Veterinary Journal and Annals of Comparative Pathology, June, 1895. "^ Regulations Governing The Meat Inspection of the United States Department of Agriculture, Bureau of Animal Industry, Order 150, as Amended, Effective Mav 1, 1908. TRANSMISSION Oh' DISHASh: llV Mh'A'l', FISH, V I'.d ETA IiLI-:s. V.) Rule A, — TIh- ciilin! cun^uHS sliull \n- coinlciniKid — (a) WIkmi it, wiis ()l)S(!rv<'iratory tracts, in(^lu(lin<>; the lymphatic ji;lands connect(;d therewith : Sj)leen, kidney, uterus, udder, ovary, testicle, adrenal fi;lan(l, brain, oi' .sj)inal cord or their nuMubranes. Numei'ous uniforridy distributed tubercles through- out both lungs also ailbrd evidence o(" generalization. (r/) When the lesions of tuberculosis are found in the riuiscles or intermuscular tissue or bones or joints, or in the l)ody lymphatic glands as a result of draining the muscles, bones, or joints. (e) When the U'sions are extensive in one or both body cavities. (/) When the lesions are multiple, acute, and actively j)rogressive. (Evidence of active progress consists in signs of acute inflammation about the lesions, or liquefaction necrosis, or the presence of young tubercles.) Rule B. — An organ or a j)art of a carcass shall be condemned — (rt) When it contains lesions of tuberculosis. (6) When the lesion is immediately adjacent to the flesh, as in the case of tuberculosis of the parietal pleura or peritoneum, not only tlie membrane or part affected but also the adjacent thoracic or alxlominal wall is to be condemned. (c) When it has been contaminated by tuberculous material, through contact with the floor, a soiled knife, or otherwise. (d) All heads showing lesions of tuberculosis shall be condemned. (e) An organ shall be condemned when the corresponding lymphatic gland is tuberculous. Rule C. — The carcass, if the tuberculous lesions are limited to a single or several parts or organs of the body (except as noted in Rule A), without evidence of recent invasion of tubercle bacilli into the sys- temic circulation, shall be passed after the parts containing the local- ized lesions are removed and condemned in accordance with Rule B. Rule D. — Carcasses which revei\l lesions more numerous than those described for carcasses to be passed (Rule C), but not so severe as the lesions described for carcasses to be condemned (Rule A), may be ren- dered into lard or tallow if the distribution of the lesions is such that all parts containing tuberculous lesions can be removed. Such car- casses shall be cooked by steam at a temperature not lower than 220° F. for not less than four hours. Meat from tuberculous cattle is infective to other animals in very 50 FOODS. variable dos^rees. As a rule, the more advanced the disease, the more likely is tiie meat to be infeetive. Experiment has demonstrated that inteetion depends to a not ineonsiderable extent upon contamination of the meat, in the process of dressing;, by the hands, knives, or cloths, which have been in contact with tuberculons matter. Although lesions in the muscular tissue itself are not at all common, positive results liave repeatedly been obtained in exi)eriments in which the expressed juice of the meat has been injected into susceptible animals. Thus, Kastner obtained 9 positive results in 11 injections of the juice of the meat of 7 tuberculous animals, and Steinheil transmitted the disease to guinea-pigs by means of juice from meat apparently sound. Arloing inoculated the muscle juice of 10 tuberculous cows into guiuea-pigs and demonstrated that that from 2 of the animals w^as infec- tive. Nocard produced the disease with the muscle juice of but 1 of 21 tuberculous cows with w^hicli he experimented. All of these cows had been condemned at the abattoir on account of extensive lesions. Woodhead, Galtier, Humbert, and others have met with varying degrees of success in similar experiments. That tuberculosis can be transmitted to animals by feeding them on tuberculous material has been abundantly proved, but the lesions pro- duced almost never invoh'e the muscular apparatus, and many of the subjects escape infection altogether. It was reported, for example, by Thomassen, at the Tuberculosis Congress at Paris, that of 10 young pigs, each of which was made to eat 4.5 kilos of meat from animals with advanced general tuberculosis, but 2 were affected, and their por- tions had contained a quantity of splintered bone. Ravenel ' has held for a long time that food tuberculosis may appear first in the lungs and cervical glands, and cites the case of 2 cows which, fed on tuberculous material, developed extensive disease of the lungs and lesions nowhere else. As stated by Dr. D. E. Salmon,^ Woodhead, St. Clair Thomp- son, and Lord Lister have shown " that infection through the medium of the food may not necessarily be accompanied by disease of the in- testines. The organs first attacked after feeding on tubercular material may be the mesenteric glands and liver, or even the bronchial and mediastinal glands and the lungs.'' Relation between Human and Bovine Tuberculosis. — The ques- tion of the identity of the bacilli of human and bovine tuberculosis, raised in 1901 by Koch's assertion of the impossibility of transference of the disease from man to cattle and from cattle to man, has led to much experimentation and study. That the human and the bovine types of B. tuberculosis are distinct, differing in virulence, morphology, and cultural peculiarities, was demonstrated by Theobald Smith five years before Koch asserted that the difference is so marked that bovine tuberculosis is a negligible factor in the human disease. In 1902 Ravenel ^ stated that the bovine bacillus shows persistent peculiarities 1 Philadelphia Medical .Journal, August 14, 1901, p. 284. ^ Bulletin No. 33, Bureau of Animal Industry, Washington, 1901. 3 Journal of Comparative Medicine and Veterinary Archives, 1902, pp. 65, 139. TRANSMISSION OF DISEASE I'.Y MEAT, EISII, VEO ETA I'.LES. 51 of ^rowili aiid iiiorpholoj^y, wliicli ciiiihlf; it to Ik; (lidiTcntiHt*'*] from tlie liiiman variety, and tliat it is j>:i(lio^ciiif', not only for nearly all of the species of oxporiniontal aninmls, hut for man also. He sayH,' inoniovor, that human hacilli vvitli a lii^li decree of virulence for experi- nuiutal animals are rarely foinid, and that cultures liijrlijy j)atho^enic for cattle an; still mon; rare. rjX))(;rimen(s conducted hy Nocard, Cij)ollina, and others indicate; that the bovine bacillus is the more infective. Nocard ^ observed liiai monkeys fed with material a^ntain- inj^ bovine bacilli became iiilec^ted much sooner than did thos(j whos^; food C()ntain(!d the human variety; and (/ij)ollina ' produced genctral tubenudosis in a healthy a|)(! with milk containing bovine bacilli, while a calf resisted infection with the human variety. The experiments of V. Dungern and Schmidt * gave results indicating a selectiv(! inf(>ctivity. Human and boviiu; bacilli were fed to anthro- poid apes; the former ])roduced tuberculosis of the lungs, the latter of the alimentary tract and mesenteric glands. In Ravenel's experiments guinea-pigs infected with human bacilli lived more than twice as long as those inoculated with the bovine variety, and rabbits were much less extensively infected and, indeed, gained in weight. That human bacilli from different lesions are differently virulent has been observed repeatedly. Those from the lungs almost invariably fail to infect calves, but Delepiue^ produced lesions in the alimentary tract of a calf to which was given 50 c.c. of mixed sputum with its food. The animal died at the end of 28 days. Bacilli from other than pulmonary lesions prove to be far more virulent. Fibiger and Jensen *' found that bacilli from 3 cases of chronic intestinal tubercu- losis were exceedingly virulent, and Wolffs produced general tubercu- losis in a calf which he inoculated with material from a similar source. In 1904 the Bureau of Animal Industry experimented with 9 cultures of human origin, and found that whereas none of the 5 derived from adults was infective for calves, 2 of 4 obtained from children with gen- eralized tuberculosis caused general infection of calves, with lesions which were quite as severe as those produced bv a fresh culture of bovine bacilli. Ravenei* found two cultures from the mesenteric glands of milk-fed children, one quite as virulent as bovine bacilli and the other more virulent than the usual human culture. Races of human tubercle bacilli have been found that are capable of producing general tuberculosis in calves and swine very quickly. Thus Dammann,* experimenting with bacilli from a human case of peritoneal tubercu- losis, produced striking cases of pulmonary tuberculosis in hogs inocu- lated subcutaneously, Avith fatal results within 28 to 42 days. 1 Journal of the American Medical Association, June 3, 1903. ^ Journal of the Sanitary Institute, Januarv. 1903, p. 571. 3 Berliner klinische Wochcnschrift, February 23, 1903. p. 163. ^ Arbeiten aus dem Kaiserlichen Gesundheitsaiute, XXIII., 1906, p. 570. 5 British Medical Journal, October 26, 1901. ® Berliner klinische Wochcnschrift, September 22, 1902. ^ Ibid., November 17, 1902. ^ Journal of the American Medical Association, June 3, 1903. ^ Deutsche Tieriirztliche Wochcnschrift, XII., 1904, p. 541. 52 FOODS. Orth 1 has convinced himself by experiment that human and bovine tubercidosis are reciprocally transmissible, and he believes that virulence can be increased materially by passage through a series of animals. Behring- increased the virulence of the human bacillus by passage through rabbits and goats, until it became as virulent for cattle as any strain of bovine bacilli ; and, according to Salmon,^ Mohler did the same by passage through five cats. Hamilton and Young* noted an enormous increase in virulence on reinoculation from one calf to another and great variation in morphological character. Arloing re- ports positive results from inoculation of cattle, asses, sheep, and hogs with human bacilli from five sources, and Theobald Smith has found a human culture directly virulent for cattle. Eber '^ inoculated a bovine animal with material from tuberculous human mesenteric glands, and from this one he reinoculated another, which succumbed to acute mil- iary tuberculosis within a week. By passing the material through a guinea-pig first and then inoculating a bovine animal, a fatal tuberculosis was produced, death occurring in 51 days. The German Tuberculosis Commission, appointed on Koch's sug- gestion, found that different bovine cultures varied much in virulence, some failing to transmit the disease to other cattle. They tested 56 cultures of human origin and found 6 that caused marked lesions in cattle, all but one from children under 7 years of age. The fact that the bacilli were from children and mainly from lesions of the intestines and mesenteric glands led Kossel ^ to conclude that the children must have been infected with bovine bacilli. His experiments show that the bovines, in a certain small proportion of cases, may yield to human bacilli, and in endeavoring to explain the fact he admits that the reverse is also true. Orth,^ having succeeded in producing general tuberculosis in 2 out of 5 calves inoculated with human bacilli, asks Koch to reconcile his own negative results with the positive results of others. The British Royal Commission on Tuberculosis examined a large number of strains of human tuberculosis material from sputum, lungs, glands, and joints, and found a number which were capable of causing remarkably severe tuberculosis in cattle, with lesions in various organs (lungs, spleen, liver, lymphatic glands, etc.). Several of the less viru- lent strains were found to gain greatly on reinoculation from one bovine into another or into a guinea-pig. The Commission concluded that in a certain proportion of cases, especially in children, human tuberculosis is the direct result of the introduction, mainly in milk, of the bovine bacillus. Of 60 cases investigated, the clinical histories of 28 indicated the entrance of the exciting cause through the alimentary canal. 1 Berliner klinjsche Wochensehrift, July 20, 1903. ' Beitriisje ziir Exper. Therapie, No. 2. 3 .Journal of the American Medical Association, March 12, 1904. 4 Public Health, September, 1903, p. 689. 5 Zeitschrift fiir Fleisch- und Milchhygiene, XVI., 1906, p. 218. « Berliner klinische Wochenschrift, July 20, 1903. 7 Ibid. TRANSMISSION OF hlSEASF. l:Y Ml!. IT, llSIt, V IJHyrM: I.ES. tA (JoiKicniintr; i\n\ possiltilit v <>' assar^ saw in ten years .'M eases of undoiii)tcd inoculation tuberculosis, chiefly in veterinarians, butchers, and others wiio handle meats. Cases of similar infection through milk are exceedingly rare. SaluKai •• cites but 3 cases in all ; one, from the a])plication of cream to a leg supposedly poisoned by ivy; a second, from milking with a womid in r)ne finger; and a third, from attempt(>d removal of tattoo-marks by the introduction of milk through needle-punctures. Raw, who in 1904 '' was led to conclude from a study of more than 3000 cases of pulmonary tuberculosis that man is subject to two kinds of tuberculosis — the pulmonary form, rare in children under twelve and due to human bacilli, and other forms, as tubercular joints, tuber- culous meningitis, and abdominal tuberculosis, rare in adults and due to bovine bacilli — is still further convinced by the study ^ of a total of 4000 cases, including 700 which came to autopsy, that bovine tuberculosis affects young people, attacking the tonsils, the alimentary tract, the glands, and through the blood, the meninges, bones, joints, and other parts, and that the human variety affects adults by way of the lungs. He asserts that the human type of bacillus causes phthisis pulmonalis, secondary ulceration of the intestines, and tuberculous laryngitis, and that the bovine type causes acute miliary tuberculosis, primary intestinal and mesenteric disease (including tabes mesenterica, tuberculous peritonitis, and tuberculosis of the pelvic organs), tubercu- lous glands, joints and bones, tuberculous meningitis, ulceration of the cornea, and lupus. Of nearly 300 cases of tabes mesenterica observed in a period of twelve years, not one of the subjects was a breast-fed child. McCaw,^ of Belfast, relates that, during the year 1906, more than 200 of 827 children treated in hos]iital were tuberculous, and lays special emphasis upon cows' milk as the cause of forms other than pul- monary. Vou Hausemann '^ gives particulars of 25 cases of intestinal 1 Zeitschrift fiir Hygiene, HI., p. 209. ' La Seniaine Medicale, October 15. 1902, p. 341. ^ Deutsclie uiedicinisolie Wochensohrift, October 2, 1901. * Bureau of Animal Industrv, Bulletin 33, 1901. 5 British Medical Journal, October 8. 1904. 6 The Lancet. August 5, 190."\ and March 2, 1907. ^ British iSledical Journal, December 21, 1907. ^ Berliner klinische Wochenschrift, 1903, Nos. 7 and 8. 54 FOODS. tuberculosis due apparently to bovine bacilli. Fibiger and Yenseu * report 2 cases of intestinal tuberculosis in infants of four and eight months respectively, deemed by them to be due undoubtedly to milk of tuberculous cows. One had had milk from a very unsanitary dairy in which a case of tuberculous udder had been notorious. Their con- tention that abdominal tuberculosis in infancy is more frequent than is commonly supposed is borne out l)y the experience of Briining- of the Leipzig Children's Hospital, who found evidences of tuberculous lesions in 44 cases which came to autopsy ; in 25 the liver and mesen- teric glands were diseased, in 20 the small intestine, in 10 the large intestine. General miliary tuberculosis was found in 25. In 8 cases there was evidence of tuberculous infection of the intestines and mesen- teric glands alone, and these must be considered as primary infections. In not one of these cases had tuberculosis been diagnosed during life, and all of the victims had died of some acute infectious disease. Von Hansemann ^ believes that infection can take place through the healthy mucous membrane, and von Behring* is of like mind. He believes that the chief source of tuberculosis is infected milk, and that infection of infants is due to lack of continuity of the epithelial lining of the alimentary tract, which permits the passage of bacteria. Evidence that infection of the lungs can occur through food without local lesions of the digestive tract is offered by several. Thus, Nicolas and Descas ^ fed fatty broth containing large numbers of tubercle bacilli to healthy dogs, some of which, after three hours, yielded chyle con- taining bacilli in such abundance that they could be demonstrated microscopically; and Ravenel^ introduced a quantity of bovine bacilli in melted butter into the stomachs of 8 healthy fasting dogs, and found that the chyle and mesenteric glands, removed about four hours later, were infective for guinea-pigs, and that not the slightest evidence of abnormality of the intestinal mucosa could be seen. MacFadyen '' obtained like results with monkeys fed with tuberculous material from cattle. General tuberculosis was produced, but no lesions of the intes- tines were observed. Calmette and Guerin ^ have proved that adult cows, as well as calves, can become infected with tuberculosis through the alimentary tract without anything in the walls of the intestine to show where the bacilli may have passed through, and they believe that pulmonary lesions in the adult are in the majority of instances of ali- mentary origin. In all of their experiments on animals, in which the infective material was introduced by the mouth with careful avoidance of inhalation, the peribronchial lymph-nodes became affected in 30 to 45 days, the lesions being the more marked the greater the num- ber of infected meals. 1 Berliner klinische Wochenschrift, February 4, 1907. ^ Hygienische Rundschau, November 15, 1906, p. 1257. 3 Loc. cit. * Deutsche medizinische Wochenschrift, 1903, No. 39. 5 Centralblatt fiir Bakteriologie, etc., 1902, XXXIL, p. 306. ® Journal of Medical Research, December, 1903, p. 460. ' The Lancet, September 12, 1903. ^ Annales de I'lnstitut Pasteur, XX., August, 1906. TRANSMISSION OF I)ISI<:ASI<: IlY M/'JAT, h'ISII, VF/lKTMlLHS. oo Tho l)(;licl" licid by (iiaiiy lli:it, sill liihcniilo.-is Dri^^inatiiif^ in tlu; intoHtiiial tract i.s of" boviiu! origin i> not .shared by TlicohaM Srnilli,' wlio i.s of opinion tiiat man lias only a limited Hn.seeplihilily to bovine tuberculosi.s, depending on e(!rtuin .still unknown fuctor.s. In ii cx^rtniri number of selecited ca.ses of alimentary tnlxrreiilo.sis l\\v. bovine baeiiliiH has been found, and, Ik; ways, all tlu; rcj.st i.s uneertiiin and sjK'enJative. ri(i l)(>liev(!s- thai ih(> ratio of (!as(!.s of inteslinal tiiberenlrK-is aH.s victim to another. Tliey are, moreover, found almost ex(;lusively among children, and possess a marked tend- ency to .s])ontaneous cure. Nevertheless, since bovine infection of the human subject is a real danger, although insignificant in compariwrn with that of the human type, proper ]>recautions should be taken to prevent its occurrence at all through food and, notably, milk. The question was again discussed in great detail at the Sixth Inter- national Congress on Tuberculosis, held in Washington in 1908. It was agreed that two types of organisms exist, differentiated, first, by the manner and rapidity of growth ; second, by differences of reactions in cultures of appropriate age, as pointed out by Theobald Smith ; and third, by very marked differences in virulence as shown by their action upon certain experimental animals. There was an attempt, further- more, to come to some general conclusion as to the importance of bovine tuberculosis in its relation to man, but no agreement on this point could be reached. Koch, although he did not deny the occasional transfer of bovine tuberculosis from animals to man, insisted that such transfer was rare, and, as supporting Koch, a series of observations reported l\v Kossel * is of great interest in this connection. From 1905 to 1909 113 cases of tuberculosis of the udder were reported, and 628 persons had par- taken of milk from these tuberculous cows. In 44 of the 113 cases the milk was said to have been cooked. In the other 69 cases it was taken raw by 360 individuals (151 children, 200 adults, and 9 of unknown age). Of these 360 individuals, only 2 became surely infected. These 2 were children, one a year and ten months old and the other a year and three months old. Both showed disease of the ^ Boston Medical and Surgical Journal, January IS, 1906. '•' American Journal of Public Hygiene, XIV., 190(3, p. 516. 3 Berliner klinische Wochenschrift, 1906, Xo. 24, p. 784. ■* Deutsche medizinisclie Wochenschrift, December 6, 1906. ' Die Sammelforechung des Kaiserlichen CTesundheits;\mtes iiber Milchgenuss und Tuberkulose. Deutsche med. "Wochensclir., Leipzig u. Berlin, 1910, XXXVI., pp. 349- 351. 56 FOODS. cervical glands. An examination of these glands showed tubercle bacilli of the bovine type. In 12 instances conditions developed which led to the suspicion only of tuberculosis. In 346 people, how- ever, and among these 136 children, no trouble ensued. Others, such as Eavenel, Arloing, and Fibiger, insisted that bovine tuberculosis, although it but infrequently caused disease of human beings, was a distinct menace to health and should be given extended consideration. The best and most recent figures are those of Park and Ivrumwiede.^ Park and Krurawiede investigated material from 606 cases of tuber- culosis, in order to determine in what percentage tubercle bacilli of the human and bovine types occurred in different varieties of the disease. The following table shows the results obtained : Total Summary of Tabulated Cases. Diagnosis of Cases Examined. Adults 16 Years and Over. Children 5 to 16 Years. Children Under 5 Years. Human. Bovine. Human. Bovine. Human. Bovine. Pulmonary tuberculosis Tuberculous adenitis. Axillary . . Tuberculous adenitis. Cervical . . Abdominal tuberculosis Generalized tuberculosis. Alimen- tary origin 290 1 13 14 6 26 4 ' 17 ' 8 1 1 1? 1 3 1 1 1 1 3 1 3 4 6 1 i 6 1 1 3 1 '3 1 1 3 12 14 2 1 7 2 9 3 2 3 7 5 1 1 6 9 1 8 4 Generalized tuberculosis Generalized tuberculosis including meninges. Alimentary origin . . Generalized tuberculosis including meninges Tubercular meningitis Tuberculosis of bones and joints . . Genito-urinary tuberculosis .... Tuberculosis of skin Miscellaneous cases : Tuberculosis of tonsils Tuberculosis of mouth and cervical nodes Tuberculous sinus or abscesses . . Sepsis. Latent bacilli 8 1 Totals .... 381 8 54 24 99 37 Mixed or double infections, 3 cases : Generalized tuberculosis : alimentary origin. 30 years. Human and bovine type in mesenteric node. Human type in bronchial node. Generalized tuberculosis : alimentary origin. 5^ years. Human type in spleen. Bovine type in mesenteric node. Generalized tuberculosis including meninges: alimentary origin. 4 years. Human type in meninges and bronchial nodes. Bovine type in mesenteric nodes. Total cases, 606. Finally, these authors combined the cases observed by them with those reported by thirty-two other reliable observers.^ This combined 1 Park and Krumwiede. The relative importance of the bovine and human types of tubercle bacilli in the different forms of human tuberculosis, Journal of Medical Kesearch, October, 1910, p. 205. 2 Smith, >Smitli and Brown, Lewis, Ravenel, deSchweinitz, Dorset and Schroeder, Mohler and Washburn, Kossel, Weber and Heuss, W^eber and Taute, Oehlecker and Dieterlen, Weber, Hoelzinger , De .Tong-Stuurmann, Dammann and Miissemaier, Henschen, Jundell and Svenson, Rabinowitsch, Beitzke, Royal Commission, Watt, Kitasato, Hess, Gorter, Fibiger and Jensen, and Burckhardt. TRANSMISSION OF hiSEASE llY MHAT, FISH, VFaF/l'AI'.LFS. :>1 liil)I(! sliows llif coiiiiinr.'iiixf - yul)- jcct ill tlic |)r((S(!iil lime. CoMitiNMi) Taiiiilaiion, Cahes Reportkd and Own Skiiikh ok Cahiw DiuynoHifc). Pulmonary tuberculosis TulxTcnlous luk'uitis. Axillary or iiiKiiiiuil 'rulKTcnldiis lulciiitis. Cervical . . Aliiliimiiuil UilxTculdHiM (iciicrali/eil Uibiirculosis. Alimen- tary orif^in (ienenili/eii tuberculosis (ieneralized tuliereulosis including nioninfres. Alimentiiry ori|,'in . . (Tcneralized tulx'rculosis including meninges 'I'uhcreular uieniuKitis Tuberculosis of bones and joints . . (ienito-urinary tuberculosis . . . . Tuberculosis of skin Miscellaneous cases: Tuberculosis of tonsils Tuberculosis of mouth and cervical nodes Tuberculous sinus or abscesses . Sepsis. Latent bacilli Totals . . . . Adults lf> Years and Over. Hi 11(1 r. to If, Human, Hovliie. Human. | r)68 1? 11 2'J 1 4 7 f. 1 1 7 ! ■1 _ i« 11 1 1 1 'Jf> 1 1 ?. 1 - — 677 9 99 f;hllrlr«'n Under .', Vfiim. 12 Mixed or double infoclions, 4 cases ; total cases, 1042. It is apparent from these tables that bovine tuberculosis decreases in importance with the increasing age of the individual. It is further- more manifest that the bovine type of the disease falls far below the human type in its im]>ortance to the human race. That young children are subject to bovine tuberculosis to a consid- erable extent, although the amount of this infection is far less than was at one time thought to be the case, and the great probability that this infection of children is due in the majority of instances to the drinking of milk of diseased cattle, makes it very evident that all etfort should be made to restrict bovine tuberculosis, not only in the commercial in- terest of the farmer, but also from the point of view of human health. As regards the cultures isolated by them, Park and Krumwiede state that 9S per cent, of all tuberculosis cultures fall into two groups so distinctive as to be surely diagnostic. The other 2 per cent., spoken of by diiferent authors as atypical or irregidar, they }>refer to speak of as viruses showing variant characters. Concerning the possibility of transmission of tuberculosis l>v eating the meat of diseased animals, there is practically no evidence of value, but whatever danger there is, if any at all, is disposed of by thorough 58 FOODS. cookiug, since thereby the bacillus is quickly killed. Since raw meat is frequently used as food, particularly in some diseased conditions, it is best, in order to be on the safe side, to see that meat so used shall be free from infective properties. Typhoid Fever and Cholera. — Foods of all kind may be made the bearers of infection to man, though themselves in good condition. Par- ticularly is this noticeable with regard to oysters, which have many times conveyed the specific organisms of typhoid fever and cholera. In 1880, Sir Charles Cameron ^ brought it to the attention of the pro- fession, that oysters, transplanted from the coast of the County of Wex- ford to the northern shore of Dublin Bay, had for some years been much subject to disease and had died in large numbers. Specimens which were examined were found to contain sewage matters, and inves- tigation showed that the beds " were literally bathed in sewage." He otfered the suggestion that raw oysters, taken from the shore close to sewer outlets, were, perhaps, as likely to act as the vehicle of typhoid fever and other diseases as contaminated water or milk, and advised that " oyster beds should not be laid down at any point on or close to the mouth of a sewer." But the warning appears to have excited no more than a languid mterest until 1893, when the late Sir R. Thorne-Thorne, in a report to the Local Government Board, stated his belief that the sporadic cases of cholera which had occurred at various inland places in England in that year were due to oysters and other shellfish from sewage-contaminated water at Grimsby, where there had been a small outbreak of the disease. In the following year occurred the well-known outbreak of typhoid fever at AVesleyan University, which was so ably and conclusively traced by Professor Conn ^ of that institution to polluted oysters. On October 20, 1894, several of the students were reported as slightly ill, with a moderate degree of fever. The number of cases grew from day to day, and shortly included several of undoubted typhoid fever. By November 1st, there Avere 20 cases of the disease, which number was shortly further increased to 23. All of the victims were men ; there was no illness among the 58 women students. Investi- gation completely absolved the water supply, the general and par- ticular food supplies of the various boarding places, and the local conditions of the dormitories and outside lodgings of all suspicion of blame. It appeared that nearly all of the victims were members of three of the seven college fraternities. The combined membership of the three was about one hundred. On October 1 2th, eight days before the development of the first symptoms, all seven fraternities had had their initiation ceremonies and had celebrated in the usual way with a supper. Investigation of the origin of the components of the suppers showed that there was but one dish from a common source, and that was oysters. The three a,fflicted societies and one other had obtained 1 British Medical Journal, September 18, 1880, p. 471. =» Medical Record, Dec. 15, 1894, p. 743. TliANSMfSS/ON OF IHSF.ASI'I /,')' MEAT, FISH, VKd FTAIi[.FS. 59 tluiir oysic^rs from ;i locnl denier; of tlu; rcMiniiiiiij.'- fliree, (\vf) liiul li;ul no oysl(;rs, ;uhI (lie (Jiird liiid li;ihoid fever attributed to cockles from the same source were the cause of the inquiry. Sewage contamination was demonstrated by the same authority in 11 of 18 lots of oysters from five different localities. Chantemesse ^ relates the following case : There had been no case of typhoid fever in the village of I'Herault Saint Andr6 de San- gonis for about a year, when, on February 15th, a shopkeeper received a consignment of oysters from Cette. The entire lot was consumed by 14 persons, all of whom were made sick. In the 6 dwellings in which the victims lived, no other inmates were sick in any way. Eight of the number were made only slightly ill, the symptoms, which in- cluded abdominal pain, vomiting, diarrhoea, borborygmus, anorexia, and general malaise, lasting but 2 or 3 days. The 4 youngest, who ate but a few, were very sick for a much longer time (15 to 25 days), but recovered. The stools were very offensive, were passed with pain, and were dysenteric in appearance ; there was tympanites with tender- ness and gurgling. All 4 were greatly prostrated. The remaining 2, a woman of twenty and a man of twenty-one, developed very severe cases of typhoid fever. The woman died. INIosny,'* to whom the French authorities referred the whole subject of mollusk poisoning for investigation, has reported that 5 members of a family of 7, living in a village in a suburb of Paris, in which there had been no case of typhoid fever in 4 years, were made sick after eating oysters sent to them from Cette. Four were seized in the evening of the following day with gastro-intestinal disturbance, which lasted 24 hours. On the eighteenth day, a youth of 17 years devel- oped unmistakable symptoms of typhoid fever, of which, 9 days later, he died. In March, 1897, Chatin^ reported the case of a family, of which several members were stricken with typhoid fever after eating oysters from a bed which was contaminated by sewage. Klein and Boyce have shown that oysters contaminated by typhoid ^ .Tom-nal of the Sanitary Institute, .January, 1903. 2 .Journal of State Medicine, March, 190.'^, p. 163. ^ Bulletin de I'Academie de Medecine, 1896, 35-36, p. 588. * Revue d'Hyj^iene, .January, February, and March, 1900. * LaSemaine Medicale, 1897, p. 9. TIlANSMISSION OF DISHASI': i:Y MI'.A'I', I'ISII, VEd F/I'A I'.IJ-IS. (\\ bacilli (;:ui nttaiii llnir inrcctivi- |)ro|)(it irs (or '1 or '.) w»'<'ks, ;ui(] it in shown tliul, lliftsc iVoiii scwaf^c-coiitiifiiiiiiii'ii lnil- iii;ty not lif c'lti n with entire, widely until (luiy have lain lor nWoiit 2 weeks in iin|)ollNt<(l water. It a|)[)ears, liowevc^r, thai in (cockles the (yplioid orj^ani.-rn thrives, and that this kind of shclKish is not free*! of its infective j)r()|)(!rties hy st()ra<^(! in clean \v;iter. Altliou;,di rockles are not eaten raw, tlu; cookinj:; to which they :ire snhjected is hy no means thoi'on<:;h, (or hoilini;- ("or :uiy con-^idefiihie time make.-, fhem toii|.;!i ;ind iHKuitable. It was shown hy Foote,' after the ontWreak at Wesleyan Univer-ity, that typiioicl cultures, introduced witiiin the cells of oysters from the bed from which the incriminated oysters were derived, were virulent at the end of 4S hours, whi(^h was the period which elaj)sed between tlie gatheriiiii; and consumption of those which caused th<; outbreak. Fur- thermore, it was demonstrated that, if the specimens were kept at 57° F., the ortranisms were active as lonj^ as a month later. The influence of the sewage of a large city is shown by C. A. Fuller,' who collected sain])les of water and shelKish from various plac<'S in Narragansctt Bay, into which about 1 4,0()(>,( 100 gallons (jf sewage from Providence, llhode Island, are discharged daily. Water, oysters, clams, and mussels, taken at a distance of a quarter of a mile from the sewer outlet, yielded BarUbin coll eoinnmnis, Bdc'dlns c/oaccc, and JUictcrium (((cfis f/.(TOf/('/(t'.s. The water and oysters from a bed two miles distant yielded the same organisms. Barilln.'i (•oil communis was fcnind in 30 per cent, of the oysters, and in 60 per cent, of the samples of \\ater from a bed situated in the line of a strong tidal current, five miles away ; and in 40 per cent, of the oysters and 70 per cent, of the water samples from another in sluggish water more than five miles away. One bed six miles distant was found to be contaminated, but those farther down than six and one-half miles were unpolluted. These findings are in accord with the statement of Dr. E. Klein,' that the nearer to sewer outlets oysters and cockles are planted, the greater the percentage of specimens yielding evidence of pollution. In the examination of oysters he holds that the presence of Bacillus enterlildls sporogcnes alone is not sufficient proof of recent sewage pol- lution, but that when the spores of this organism are found together with streptococci and Bacillus coll communis they constitute strong evidence of recent contamination. Dr. Hibbert W. Hill ^ has recorded interesting results of examination of clams from flats in the immediate vicinity of the sewer outlets of a number of private dwellings. Attention was devoted solely to the bodies of the clams and not to the water contained between the shells, which was practiciilly the same as that which surrounded them. The technique followed was such as to insure absolutely against contamiua- ^ Medical News, March "Jo, 1895. ' Science, 1902, No. 875. p. o63. ^ British Medical Journal, February 21, 1903. * Report of the Board of Health of Boston, Massachusetts, for 1901. 62 FOODS. tion by bacteria on the surface, and the portion of the body selected as most likely to show infection was the intestines. The following were isolated and identitied : Bacillus coll comvmnis, Bacillns enter itidis sporofjcncs, and Bacillus acrogcnes capsulatus (Welch), all three of which are found commonly in sewage. The typhoid bacillus was not found nor was it expected, since there was but 1 case in the neighbor- hood and the excreta were disinfected. Dr. Hill adds that the search for typhoid bacilli in sewage known to contain them is, in most cases, practically hopeless, since even in severe epidemics the number of typhoid patients contributing to the sewage is almost always small in comparis(ni with the total contributing persons, and only a small pro- portion of the bacteria present in a typhoid stool are typhoid bacilli ; and to hope to find, by examining a few cubic centimeters from a large mass of w'ater, a bacillus which is present in the proportion of one to every ten or hundred gallons of water, is almost, if not quite, useless. From a series of experiments undertaken to determine the question of viability of the typhoid organism in sea water and within the oyster, Bordoni-UlFreduzzi and Zernoni^ concluded that it will live over 2 weeks in sea water and from 3 to 4 days in oysters, without lessening of virulence. Oysters from Spezia, Venice, and elsewhere, were exammed to determine the presence of the typhoid organism in the water contained between the shells or in the tissues. The results were negative on this point, but the colon bacillus was isolated from oysters from 3 different sources. Oysters immersed in sterilized sea water, which later was infected with cultures of the typhoid organism, yielded virulent bacilli from the water between their shells up to the ninth day of examination, but never from the tissues themselves. Stokes^ examined 87 specimens of oysters from various sources and found the colon bacillus in 33 or 37.9 per cent. ; 2 out of 33 clams showed the presence of the colon bacillus (6 per cent.). Altogether 120 shellfish were examined, of which 35 or 29.1 per cent, showed the presence of the colon bacillus. The number of bacteria per cubic cen- timeter of the juice of the oysters varied from to 14,400. For the clams the counts varied from to 3600. Furthermore, Stokes was able to isolate two organisms from market oysters which corresponded to the typhoid bacillus in morphology, mo- tility, staining characteristics, and all cultural properties. They were, furthermore, pathogenic for guinea-pigs. Agglutination tests gave results which were suggestive, but not abso- lutely characteristic of the typhoid bacillus. Johnstone ^ examined oysters taken from deep sea beds and found them practically free from bacteria. He succeeded only once in iso- lating the typhoid bacillus from shellfish. This positive result was obtained in a mussel taken from a bed near a sewer outlet. ^ Giornale della Reale Societa Italiana d'igiene, 1899, p. 500. ^ Annual report, Health Department, City of Baltimore, 1909. 3 Jour. Hyg., Cambridge, 1909, p. 412. TRANSMISSION OF IHSKASI': liV M KAT, FISH, VK<1 F'l'A liLFS. 03 ()(>Ii(!r ()l),sorvcrH li;iv(! foiiiid Ui« Wactcriu of flioiini uikI l.yplioi*! f«;v<;r, II. coll coianiMiiis, />'. jn-oiciiH vidf/ariM, aii(J otlicr or^raiii.srriH, in oynUifH (M)iil,;i,riiiii:il.c'. coil coviiniiiil.s sliDiild ar<)n.s(! sn.s|)icioM and indn«;e iniprovcrncntii in the managcnKMii and snixTvision of oyster Ix-dH. Tn the investi!i;alion of onthreaUs of typhoid icver HUpposjjdly duf; io oystofs, hac,t(M-i()lo^ie,al j)roof of H|)e(!i(ic infe(!tion of thoHf; eaten or of othens from the saniiis tliioii^'-lioiiL S<)rii<; an; poisonous only in iJu- raw sfiilc, iiiid others wlicflicr cook-cd «»r nof, TIh! svin|)l(»ins prodiKM'd v.iry widely, soinelinie- indienf injr ^urivo- (Mitcrilis, sometimes iiivolvfiinent of IIk; eentrai nervous Hysfem. 'I'lie IMUSS(.'1 is rei^arded not un(H)mMioidy as an intrinsir'ally poisonoiiH slielllisli, hut tlu! weij^lit o(" cvidenee indicates lli:it innssel-poi-onin^'- is diK! to conditions o(" disease or iidecrtion ;irisinif/ s('.n,s(!H, Tn many oaw'H, tlio j)oiHononH principN s uf»j)car U) b(! (l(!V(!l()|). ciilcrilidi.s), l>as((iiaii (/>. Aow/.v 'iiiorh'ijicdiiK), Kaensf-lir; {II, Mo7'iiceLcimH and Ji. J}rc,sfavicnsiii),(ji'diVky and Vank (li. J'ricdcherr/en- sis), Abel, Giinther, and others, besides Ji. proteus vulgaris, B. protetia mirdhilin, jt^laplii/foc.occiiN jyi/or/oics Jlavus, and others. The first men- tioned (/>. I)()tntlnat^) ])ro(hi(!es an extraordinarily virnlcnt toxin, which has been the snljjccit of (^arelid investij^ation, wliieli li:is proved that it is related closely to the toxins of diphtheria and tetanus. Study of a bacillus which Trautraaun ' isolated as the cause of an outbreak of poisoning at Diisseldorf, and eomj)arison thereof with cul- tures of B. Fricdchcn/ensis, B. enter iLldiH, Jl. Morsrelensis, B. hovis morbifiGanx, B. Brefilavicnsis, and of the organisms isolated by Fischer, Abel, and Giinther, and also of the various strains of paratyphoid bacilli, led him to the conclusion that, while these several kinds present slight differences in morphology and cultural peculiarities, they show no fundamental ditference and are merely varieties of one and the same organism. Others have called attention to the similarity of symptoms in meat-poisoning (not botulism) and paratyjihoid, and the belief is growing that the differences in the nature and severity of symptoms and in the order of their appearance are dependent upon the slight racial difterences in the bacteria and upon the degree of virulence and individual susceptibility. Many outbreaks of meat-poisoning have been indistinguishable from paratyjihoid, and many of severe form have been mistaken for true typhoid. Trautmann believes that the tyj>ical meat-poisoning is the hyperacute, and paratyphoid the subacute, mani- festation of au etiologically similar disturbance, and he places all of the exciting causes under the general head of B. i^aratyphosus. It has not been supposed that the organisms which cause meat-poi- soning of the more common types, such as the Bacillus botulinus and the B. oiteritidis of Gaertner, are widely distributed in nature, but the fol- lowing statements will show^ that the danger of iufectiou is not to be lightly disregarded. Ivlein,^ for instance, found the B. enteritidis of Gaertner in ten out of thirty-nine milk samples which had been col- lected for examination for tuberculosis. The number of organisms was not large, to be sure, but if this milk had been kept in suitable sur- roundings of temperature it could have become very dangerous. The farm from which this milk came was a very dirty one. Conradi ^ found paratyphoid bacilli in natural ice from various sources, and suggests that this may be the origin of paratyphoid 1 Zeitsobrift fiir Hvsriene und Infectionskrankheiten. XLV., p. 139, and XL VI., p. 6S. -' Centralb. f. Bakt." Orii-.. Vol. XXXVIII., 1905. 3 Munch, Med. Woch,, May 4, Vol. LVI., pp. 897 and 952, 68 FOODS. infection in certain cases. He fouml, furthermore, that cliopped ice is mixed with the meat in certain districts in the process of making sau- saijes. Uhlenhnth ^ examined a number of healthy hogs killed at the abat- toir in Berlin ; G per cent, of the cases showed bacilli very similar to paratyphoid,' tyjie B. l\impau- found twenty-six persons who were excreting paraty])hoid bacilli, type B ; 10 of these were sick typhoids, 5 were typhoid bacil- lus carriers, and 11 were healthy individuals. His investigation brought out three iniportant points : First, the frequent occurrence of these bacilli in the urine ; second, bacilli were present in persons who had been in contact with those sick with })aratyphoid B infection ; third, the occurrence of this organism in external nature. Of the 26 cases, the germs were found 15 times in the nrine and stools, and 9 times in the urine alone. They may be found in the blood without caus- ing any symptoms, and once were found in the blood of a true tyjihoid. He found this bacillus also in the stools of fifty presumably healthy school boys. Rimpau found it also in a perfectly good sausage. Hiibener^ examined 100 samples of sausage and found paratyphoid organisms of this type in 6. The sausage was apparently good and caused no disagreeable symptoms. Duchan * quotes Ford^ as having found the B. cnteriiidis of Gaert- ner in the large intestine of a human subject. He quotes Savage also as having found members of the Gaertner group in the intestines of four pigs. In one of these they were present in large numbers. Signs Pointing to an Epidemic. — Vagedes ^ gives three chief indi- cations for an epidemic of food poisoning. First, sudden appearance of poisoning in ]5ersons up to that time perfectly well ; second, symp- toms of illness following the ingestion of a certain food product ; third, sickness in several persons who have eaten the same food product. Onset and Course of Symptoms. — The first symptoms in cases of poisoning by fish and meats may occur within an hour or two after eat- ing or may be delayed a number of days. In one outbreak cited (see Poisoning by Herrings, page 73), in which 5 persons were seized, the initial symptoms appeared in 2, 3, 5, 7, and 9 clays respectively ; ordinarily they appear within a few hours — 3, 6, 12. When numbers of persons are affected by the same food, the onset is by no means uni- form. In the Ellezelles case (see page 81), in which 20 jiersons were seized, the time in which the symptoms first were manifested ranged from 3 to 36 hours, but as a rule, it is the appearance ^vithiu the same day of similar symptoms in a number of persons which calls attention 1 Deutsch. Med. Woch., 1907, No. 11. ^ Zur Frage der Verbreitung der B. ans der Paratvphus Gruppe, Deutsch. Med. Woch., 1908,' 124. ^ Ueher das Vorkommen von Bakterien der paratvphus Gruppe in der Aussenwelt, Deutsch. Med. Woch., lOOS, No. 24. * Public Health, ,Jnlv, 1908. ^ Studies from the Rockefeller Institute, Vol. II., 1904. « Vieileljahrschr. f. Gerichtl. Medizin., Vol. XXIX., 1905. r<>is(>Ni\'(i r.y meat am> fish. 60 to tlio food Hiij)j»ly ;iH ji (loiiiiiioM cniisf! of tlio troiihh;. I'oiKOiiinj^ l>y ptoiiiiiiiis is iii;iiiircslc(| (rciicnilly wifliin ;i few lioiirs. In (',iiH(W of i';i|)iil onset, Ihc prourcss clllicr lo recovery or ;i I'ahil i(!rmiii;i(,ioii is coiiimoiily sliorl,, hut may he soineliincH a iiiaU<;r (»f" tiioiil.lis, and in [\\v.m\ (txcrcplional caHt« event mil rce^ovory is prohahK;. Tho shortiist case on re(!ord is that, of nnissel-poisoninj^ at Wilhehn.s- liavcMi (hog |)a<;(! 72), in which 1 victim (Med in 2, another in '.), and 2 others in 5 hoiu's after eatina;. A ])(!cnliaf t(!ndcn(y to rcilapscis oflxsn is obs(!rvcd. The patient hc^in.H to itn])r()ve, wh(Mi snddcnly the oriii|)(:d coriiinonly iiiidcT t.lic \wm\ <)(■ dinrrlKca. II(! I'cd IIk; frcsli meat, of f)ii<; of llurs(! r^ilvcw io mI(U! and o;iiinc;i-|)ij:;s, wliirli died williin a i'vw dayH with f;iit<;ntw. From th(! hone ni;iri-ovv \n\ isoljitcd ;in or}/;anisin which apjM-nrs lo be rc- hitod closely to (jiiKirtncr'H /*. oifcrU.ldis, and which on inoculation into aniinids |)r()du(!('S a, filial cntcrilis. /;,;,/. — 15(!cf-|)oisonin<; has been notic('d willi coiisidcr.iblc frc(jucn(ry, followinfr the use of meat from animals KJaufrhtcrcd while Hick, and it has be(Mi pointcid out by M(!vcral observers that cortidn scj)tic di.s^iscs of cattle are cspeei;dly prone to render meat poisonous. These include the .septic form of calf paralysis, hemorrhagic enteritis of calv(;s, .sejitic metritis of cows, various intestinal disorders, the He])ticx)-j)yamiic dis- eases, and a numl^cr of others. Gaertner's B. enteritidis was disc/jvered by him oriti:;inally in the Hosh of a cow that had been slautrht^'red on account of a severe diarrluea, and in tlu; spleen of a ])crson who died in consequence of eatin*^ it. He showed that not only the bacillus, but also its boiled bouillon cultures, are highly toxic. Many deaths have been recorded as a consequence of eating the cooked meat of cows slaughtered on account of ])uerperal fever, and it was from such an animal that Basenau isolated />. Aoc/.s- morhificfnis. This cow showed such lesions of the viscera that the director of the Amsterdam abattoir forbade the use of the meat. Basenau* has examined the flesh of beeves which had succumbed to a variety of diseases, and he has isolated a numl)cr of species of bac- teria bearing a close resemblance to i>. bovis inorhlf}cf(}i.'<, all of which are fatal to mice. Some of them produce poisonous mattei's which withstand boiling without impairment of their properties. Ordinan*' mspcction being useless for determining whether such meat is infected, he recommends that bacteriological and feechng ex]X'riments should be instituted toii'ether within 24 h(>urs after slaughtering. If no colonies are observed at the end of 24 hours and no bacteria are seen in the tis- sues, the meat may be regarded as safe to eat. If colonies are yielded, the acceptance or rejection of the meat must depend upon the results of the feeding experiments. If the mice fed on the raw meat die and those fed on the cooked meat survive, it may be concluded that the meat is safe, if thoroughly cooked. If both die, the meat should unhesitatingly be condemned. Sausaac. — Sausage has loup- been recognized as a verv common cause of poisoning, and has a much larger record of accidents than any other meat or meat compound. This is due in large part to a very common practice of nialdug use of all manner of uninviting fragments and scraps of meat, oftal, and the flesh of sick and ill-conditi oc(5urr(!(l, iti c()nsc(jii<'nc-(! oC wliif'li (lie niii^istr.ilcs isHUcd a wurnirig ajraJiisI, IJk! iis(! of" miisscls, \)v. ('oiiilx' foiiiid l»iit, lliii-(y cMscn with two (leaMis. Ill :ill, i\\r syiiipt.nins prcscnlcd ;i -t rik in;/ iini (onnit y, tlioiij^li tliey varied nmcli in s(!V(!i'ily. Mo.^l of I he \iii(Ml with snlt iiinl pepper, ami none liad wAiccA any urniHiial taHte. Ill atients ^ave positive afrghitination tests with the same organism. Ulrieh believes that fish should never be eaten later than twenty-four hours after it has been cooked. Abraham^ reports twenty-eight cases of poisoning after eating ))ikc. In eighteen hours there occurred severe colic, nausea, and diarrhoea. The infection had some resemblance to typhoid fever. A piece of the suspected fish presented a good aji])earance and showed no evidence of ptomains or metallic })oisons. Prof. Neisscr found in the fish bacilli of the paratyphoid or meat-])oisoning group (type Aertryck). The toxin produced by this organism was resistant to heat and the blood of the patient gave with this organism positive agglutination tests. The specific bacilli could not, however, be found in the stools of the patients. It is, therefore, most probable that the fish was infected during life. It is said that pike favor localities like sewer outlets, and could easily become infected. There were no deaths among the.se patients. Poisoning by Oysters. — Case I. — The following case, which ended fatally, is reported by Brosch.^ An officer ate a number of oysters toward midnight, ami within 6 hours was seized with headache, pain in the side, nausea, dimness of sight, difficult deglutition, retention of urine, and salivation. Toward noon, right facial paralysis, dilatation of the right pupil, and thickness of speech appeared, followed shortly by cyanosis, ptosis of the right eyelid, great muscular relaxation, and paralysis of respiration. Autopsy reveiiled punctiform ecchymoses in various parts, enlargement of the spleen, and fatty degeneration of the liver and kidneys. Case IL — Another fatal case is recorded by Casey * " H. P., about 32 years of age, ate 8 oysters for supper, remarking at the time that one of them was bad. Others of the same lot appeared to be quite fresh and were eateu by other persons with impunity. Symptoms of poisoning began about 12—14 h(^urs later, with pain in the back. s«x>n followed by violent paius m the stomach, frequent vomitmg, and intense 1 Zeit. f. Hyg., Vol. LIIL, 1906. ^Miinch. Med. Woch., 1906. No. 50, p. 2466. ^ Wiener klinisclie Wochensolirift, 1896, Xo. 13. ■* British Medical Journal, March 3, 1894, p. 463. 76 FOODS. thirst. The bowels did not act. Tliesc symptoms continued until the following morning, when the pulse, which had been small and quick, became almost imperceptible, the fingers shrunken, the nails blue. The tongue was at that time dark and swollen, and swallowing difficult. There were occasional spasms of the arms. A little later, the ja\v' became set, and soon, after a sudden struggle for breath, he died, 41 hours after eating the oysters. At the post-mortem examination, the heart -was found to be very soft and relaxed and contained fluid blood. The kidneys and spleen were also very soft and congested ; the stomach emjitv and darklv congested ; the peritoneum was thickly studded with flecks of lymph.'' Poisoning' by Veal. — Boyer ^ reports the following case of sextuple poisoning by veal. The persons aifccted were members of one h(»usehold, and ranged widely in pouit of age, the yoimgest being children of 3 and (3 years. The symptoms appeared in the night, about 6 hours after the food was taken, and began with vomiting and violent colic. In the morning, all had intense gastric irritability, coated t<)ngue, pain on pressure, especially in the right iliac fossa, rumbling, slight tympanites, and scanty urine. The cook had markedly dilated pupils, a sensation of suffocation, constriction and dryness of the throat, and intense suffusion of the face. The child of 6 had dilated pupils and disturbance of vision, and finally pain and stiffness of the muscles of the neck. The younger of the two children and the mother were affected less than the others, and made a more rapid recovery. The chambermaid had at first a certain degree of aggravation of symj)- toms, with a tendency to syncope and great muscular weakness, which latter effects were maiked also in the case of the cook, who continued for some time to be troubled by dilatation of the pupils and disturbed vision. At the end of nine days, there was no evidence of danger, and the two most severely affected were well on the way to recovery. Unfortunately, no bacteriological examination was made either of the meat or the discharges, but the nature of the symptoms leaves no room for doubt as to their cause. Case IT. — Drs. Wilkinson,^ Ashton, and Durham have recorded an extensive outbreak of poisoning due to imperfectly cooked veal pies. All the cases, over fifty in number, presented very similar symj)- toms, the chief of which were severe and uncontrollable vomiting and diarrhoea, accompanied at first by shivering, and followed by collajjse. In some there were violent abdominal pains, and in several the abdo- men was swollen and tender. Many had severe pains in the back. The symptoms began in from 5 to 14 hours after eating, and, as a rule, were severe from the start. The motions were first grass-green, then dark green, and highly offensive. The severity of the diarrhoea in- creased on the second day ; one patient was purged 40 or more times in a single day. In very fe^v cases, the dejecta contained a little blood. ' Lyon medical, May 14, 1899. ^ Public Health, Januaiy, 1899, and British Medical Journal, December 17, 1898. CASES njjis'rn.\'rivi<: <>i'' roisosisc r.v iisii asd mi:.\t. 11 III \hv worsi, <':isc.s, (he |i;iliiiils Iicciuik; Hciiii-coniutoHc, rcstlc.'-H, :iinl delirious in llic cdiirH' oC ;i liw Ikmii-,-;. Occasionally, tlKfn; were jIIh- iiirhMiK^cs i)[' vision, which lasted iinlil liic f<'iii|)('ralnrc, wliic^li raiijr<'d ironi 100'^ in Ihc niildcsl to 101. 5'' V. in the scvcrrsi cmscs, hfcjiriu- n<*r- nuil. The j)uls(( was wvy r'lipid, wc'ik, ;iiid ;iin ;ind stilViKtHH, Til very many cas<^s, herpes ;i|)|)e;ircd ;d)ont the lips on ihc third to the sixth day, and sonic; had a lash rollf)Wc(j hy dcs((n:ini;ition. C'on- valos(!oncc in the scvei'c; cases was ])rolon:,"ei" and iiioih; iiiimiM'oiis lower down, and did not correspond with Peyer's j)atches. The whole lower third was hij^hly con^eKtcd, and contained yellow diarrh;ill;ir of these follows : 1. VV. W., a<^ed ()4, ate luim on Wednesday and Friday, and was seized on I^'riday ni M/:A7'. H\ around llic simkcii tycs. 'I'lic (lcl)ilit,y oi' (;(jMval(;.s(;(:ii(;c \v:i- in iicirly all ciiKcs |)n»(r;ic(('(l l<» scvcr.-il W(!('In(l ilic (ullowin^' syniploms, viz., altdominal |»ains, vomit iii^r, foinid in most cas(>,s to ])rodnee a ])nennionia. 'riie period of inciibal ion indicates llial in these eases there waH a triu^ bai'terial infection. Casio III. — Another epidemic investigated by Uallard ' involved a far <2;reMter nnmbei" of persons and had an imnsnal atfendaht mortality, nearly AOO persons ont of a jnipnlation of abont 'l(U),()()() (Middlc^sbron^'h) dvini;' dnrin^^ the \i-,w of a ]»cenliar form of |)lenro- pneumonia. The caiiso of this I'emarkable e])ideinie was ])roved to be the c-on- sunij)tioii of what was known as "Aiiieriean baeon," a food ])i-oduct prepared from imported salt pork at a number of loeal cstablislnnents conducted under most unsanitary conditions. Twenty samples of bacon, some obtained at shops and some at the homes of victim.s, were examined, and fourteen were found to be distinctly poisonous to animals. The lesions discovered in the dead animals were of the same nature and extent of those in the organs of the persons who had died. These included destructive changes in all the principal viscera, and more particularly in the lungs. Dr. Klein discovered in the lung a short bacillus which had never before been described. Inoculati(»n exjKn'iments on animals produced results identical with those following feeding experiments with the so-called bacon. Case IV. — A remarkable outbreak due to raw pickled ham has been recorded by Van Ermengem^ and carefully investigated by him- self and others. More thau twenty members of a musical society at Ellezelles, in Belgium, were seized with serious illness after eating the greater part of a raw pickled ham ; three died withm a week, and ten lay in a critical condition. Other parts of the animal from the same pickling tub were eaten in a raw state Avithout ill effects, and pieces of the particular ham had been consumed a short time before, also without . ill effects. Only those persons who ate of the ham were seized -with the very peculiar train of symptoms recorded. Most of them were seized in from 20 to 24 hours, 3 in less than that time, and a few as late as 86 hours after eating. The iirst symptoms were gastric pain, nausea, and vomitiug of mi- digested food and gelatinous blackish matters. lusteiid of diarrhoea, which one would expect, there was obstinate constipation in all but 2 cases, and the tirst dejections, with or without cathartics, were black and viscid. In every case, in from oG to 48 Ikhu's, there were pro- found disturbances of vision — amphodiplopia, markai dilatation of the > Supplement to 18th Annual Eeport of the Local Government Board, 1S89, p. 163. ^ Zeitschrift fiir Hygiene und Infoctionskrankheiten, XXVI., p. 1. 82 FOODS. pupils, with absence of reaction to light, ptosis of both lids, and a peculiar fixed stare. There was burnino- thirst with a stranglino; sensa- tion in the throat. Swallowino-, even of H(|uids, was difficult or impos- sible, and every attempt was accompanied by choking. In some instances, the saliva was suppressed and the mucous mem- brane dry and glossy. The voice was weak, and with some there was total aphonia. Dysuria and anuria were common. Tiiere was but little disturbance of respiration and circulation ; tlie pulse never reached over 90, respiration was quiet, temperature normal. Consciousness and geueml sensibility remained unimpaired throughout, except in the fatal cases, in Avhich alone, several hours before death, there occurred collapse, dyspnoea, small irregular pulse, light delirium, and coma. There was obstinate insomnia in many, during the first period. The extremities and trunk muscles showed neither complete paralysis nor atrophy, but there was great general muscular weakness, and slight movements caused extreme fatigue. After two or three weeks, the eye symjitoms began to improve. The dilated pupils contracted, the cloudi- ness disappeared, and the half-paralyzed eyelids regained their power. Diplopia disappeared only when both eyes were fixed laterally. Par- alysis of accommodation lasted a long time after the disappearance of all the other symptoms, and normal vision did not return until after six to eight months. Autopsy in two cases showed no characteristic changes in the organs, only extensive hypersemia of the kidneys, liver, and meninges, and softening and unusual friability of the stomach Avails. In one, the liver showed marked degeneration, and the brain punctiform hemorrhages. Neither the liver nor kidneys showed anything unusual on bacteriologi- cal examination, but the s^^leen yielded an anaerobic bacillus, which proved later to be capable of causing botulism. The pig from which the ham came was killed some months pre- viously, and what was not eaten at once was pickled in the usual way. During the time that elapsed between the pickling and the supper, the greater part of the animal had been consumed without causing any sickness, but the ham which was nearly intact was the last to be eaten, lay on the bottom of the tub, and was the only part that was immersed completely in the weak brine. What was left of it gave no odor of putridity, but had a distinct odor like that of rancid butter. That the ham had a bad taste, was agreed by nearly all who ate of it. It appeared normal to the eye, but was pale, like any meat that has been soaked some time in water. There was no evidence of decomposition, and no ptomains were detected. Bacteriological examination proved in different parts the presence of a hitherto unknown spore-bearing bacillus in great abundance, the same organism as that isolated from the spleen of one of the victims. It produced an extraordinarily virulent toxin, which was isolated by Brieger from cultures supplied by the discoverer, by whom the organ- ism was named Bacillus botidinus. The toxin is rendered inert by a temperature of 60° to 70° C, therein agreeing with other bacterial toxins thus far isolated. CASKS' /LLdS'rnA'nvh' or roisoNisc i;y iisii AM) Mi:Ar. K) Ali.(!iti|»(s to (lis('()V(!r IIk! or^iuiiMin in llic Icccs of varioiiH aiiitn:ilH jiikI ill (illii of v.'irioiis kinds, jhkI in spccinicns Croin wlicrc llu- jii^' wjih raised were nc^iilivc in rcsiills. Fc(;diii,i!;-('X|"'riiii('ii(s, condiu'tc*! on \';irion- kind- itf ;niini;d.- ullli iIk; meat itself :ind willi ;i(|neons I riliii';il ions of il ;id(k'd lo oilier food-, pn)- dneed,ns a rule, filial resiilfs with llie same tniin of syniptonis ;is ;d)ov«! nieii(ioiie(k SiibentniXMHis iiijeetions of f lie walcrv exlrael |»rodiieed tlio H:uiie results as feediiit:;-ex|)eriinen(s. TIk" ;i(|iieoiis extr;iet kept in tlie dark in ;i scMJed (iiiie rel;iiii<'<| i(s properl ies unimpaired for 1 inotitliK, and sninll pieces of I lie iiie.if kcpl in eollon-stoiyix-red tiihes witlioilt SjH'cial preeniilioiis relaiiie(l t lieir viriilenee cN'en lon^'cr. Tlie poison resists tlu^ elfeels of piitreliietion, iiiid |)roved fo lie e(pi:illy jioisoiioiiH after 4 diivs' slandiiii;- in ,i inixluie willi feces, decoinposiiijr Mood ami urine, and fill i-ntioii lliroiinli porcelnin. >\ fresli (iltnite, to wliicli wore added //. prodii/iosiis, II. jh-oIchx liijiicfdi-'inis^ /I. fiioreHceriH jndrhleH, and B. coil, was found at l)ic end ol" a week to he as active a.s ever. Mayer ^ reports an epidemic in which several pei'sons were infected with para-typhoid bacillus throuse of time. It is supposed to have acquired the invading Itacterium from a slaughterhouse in close proximity to the spot upon which it was cooled. The organisms isolated proved to be of the type of the Bacillus enferi- tidis of Gaertner, as proved by cultural characteristics and aggluti- nation tests with the patients' serum. 1 Cent. f. Bakt., 3 910, Bd. 53. • ^ The Lancet, Dec. 7, 1907. 84 FOODS. Poisoning" by Beef. — Case I. — In December, 1841, more than 40 cases of poisoning occurred in New York City from eating smoketl beef. As a rule the symptoms began several hours after eating, with pain and discomfort in the epigastrium, extending to the back and loins. Vomiting and purging were followed by great thirst and burning pain at tlie pit of the stomach, which became so irrital)k' that it could tolerate neither food nor drugs. Extreme prostration followed, the functions of the nervous and muscular system being greatly affected. One victim died, and with the others convalescence was extremely slow. Autopsy revealed nothing beyond inflammation of the ileum. Case II. — In May, 1888, at Fraukenhausen, 58 persons were made sick by eating the meat of a cow killed while ill with diarrhoea and passed as edible by a veterinary. The symptoms were, in general, nausea, vomiting, diarrhoea, fever, drowsiness, dizziness, and great de- pression. Those who ate the meat in the raw state were seized without exception, and the severity of the seizure was directly proportionate to the amount eaten. One victim who ate a pound and a half died within 35 hours, while those who ate least suffered least. Those who ate the cooked meat fared differently. Not all were attacked, nor did the severity of the symptoms bear any relation to the amount taken. Thus, some who ate freely suffered but little, while very severe effects were caused by slight amounts of the meat, and even by small por- tions of the broth. Thirty-six who ate the cooked meat escaped altogether. From a portion of the meat, and from the spleen of tlie person who died, Gaertner' isolated B. enteritldis, M^hich, since then, has been shown to have been the cause of numerous other outbreaks. Case III. — In June, 1889, 137 persons, including 50 children, in and about Cotta, in Saxony,^ were made ill by eating the meat of a cow slaughtered on June 17th, because of an inflammatory condition of the udder. On the 11th, she had suddenly stopped giving milk and had refused food and drink. The meat appeared to be normal in every way and was sold on the day after slaughter. The first cases appeared during the night of the day of sale. The majority of the victims had eaten the minced meat in the raw state, others only after it had been cooked, and some had eaten only broth. The butcher who sold the meat tasted as much as would cover a knife-blade, and suffered from diarrhoea, headache, and abdominal pain for three days. His as- sistant did the same, and fared even worse. In one case, the symptoms began with a chill; in another, with difficult deglutition, double vision, and anxiety; in the rest, with nausea, vomiting, diarrhoea, headache, abdominal pain, dizziness, great lassitude, restlessness, lethargy, and unquenchal;)le thirst. In many cases, the eyes were glassy, and the pupils much dilated. The tongue was commonly dry and coated. The children affected were extraordinarily weak, and some had fever as high as 104.7° F. A bacillus isolated from the meat by Johne was found by Gaertner to differ in some respects from B. enteritldis. ' Correspondenz-Blatter des allgemeinen iirztlichen Vereins von Thiiringen, No. V). ■^ XXI. Jahresbericht ueber das Medicinalwesen im Konigreich Sachsen, p. 104, CAHKs iIjUis'I'iiativI': or I'oisoi^isa itv fish ASh meat. 80 C/AHK IV. — l*()is(iiiiii(i; liy (iiKUHMl corned hccf ;il Slir'lTi(|(|, i-cportcd by W. N. l':irl<('i'.' On Oclolx-r I I, I «!»!», ii .HX-|)onnproximate latent period varied between one and three and a half hours, but in only 2 cases was it more than two and a lialf hours. Frontal headache was present in all but 4, vomiting in all but 1, pain in only 12, marked collapse in 12, profuse discharges in all but 6. The initial symptoms were the same in all; that is, drowsiness or giddiness, or both. Only one case resulted fatally, that of a boy 7 years old, who ate 2 ounces. His symptoms were especially severe ; collapse was very marked and he required constant stimulation. About 10 hours after the onset, he had a series of clonic contractions of the flexor muscles of the neck, arms, and legs. The movements were violent, rapid, and almost rhythmical, commencing first in the neck and arms, but soon affecting the legs. The eyes were fixed and staring, and the pupils widely dilated. After lasting an honr and a half, the convul- sions ceased. They reappeared in half an hour, affecting first the right arm and right side of the face, but soon became general. The collapse gradually deepened, and the boy died 15 hours after seizure. Autopsy showed nothing more than a general hypen^mia of the stomach and intestines, with a few hemorrhagic erosions in the gastric mucous membrane. A microscopic examination of the kidney showed cloudy swelling of the cortex, with a few scattered hemorrhages. » British Medical Journal, Xovember 11, 1899. 86 • FOODS. All the other victims convnloseed ra}>icny and wove diH;ehar(i;ed from the hosjHtal Avithiii 48 hours. Stimulants, ehietly in the form of stryeh- nine and brandy, were administered freely. The meat was examined bacteriologically about 1 1 hours after the tin was said to have been opened. In the outer parts of the meat, many species of organisms wore found. " The only organism ])reseut both in cultures from the centre of the meat and in those from the surface was the bacillus of Gaertner. Case V. — An outbreak at Mansfield, in which 65 persons became ill after eating the flesh of a cow slaughtered in consequence of trau- matic pericarditis, has been reported l)y Wesenberg.^ Only those who ate of the minced meat in a raw state or of the partly cooked liver were affected ; those who ate of the well-cooked meat escaped without exception. The symptoms were vomiting and diarrhoea, violent headache and abdominal pain, general muscular weakness, dizziness and lassitude. The discharges were sometimes greenish, sometimes brownish, and always extremely offensive. With few excep- tions, the symptoms abated in from 3 to 5 days, and all recovered except one, and that a doubtful case of a child who was not known ■with certainty to have partaken, and whose symptoms might have been due to other causes. The unconsumed meat when received for examination was already fairly ^vell advanced in decomposition and partly maggoty. All except one piece, which was faintly acid to litmus papers, was alkaline in reaction. Cultures on agar and in bouillon were made from a piece taken from a part which was apparently not yet in process of decom- position. Inoculation of the bouillon cultures and of small bits of the meat into white mice produced fatal results, in some cases within from 1 mi: at. 87 tr(!rnl)lin^, iind ^^icmI. (Iiirs',. Tlic (ciiipcrjiiiin! roHc to lOJ'' F. ()\u- cuse tdrniiiiaicd (iitully. IJiictcriolojrlc.iil <'x;iiiiiii;ili(ni i(v«'al(;(i a, hacil- luH wliicli (lidorwl in some rcHpccts I'loni tli;if uT ( inert ii I (lut. ol" (iO pcrsonH who had oat(Mi <)(" a, single hatch oC sansaf:;('s. Tlic onset waH churactiTizi-d hy vomitinfj^, pnri^in^-, and (li//in{!ss, which came f»ii art<'i' int<'rvals of varyiiifjj kinfjjlJi. There was cxtnMiie weakness, and many had seven! (',i"arn|)s in the h'^^s and pains in th(! ah(h)inen. In (he inajorify of eases the vonii(-in]3eared within a short time, were the same in kind in all, but ditlered in severity. Tluy included abdonn'nal pain, vomiting, dizziness, dryness of the mouth and throat, an SI.AIK; llTElLlNfl. 80 wat(Ty iuid hr-ovvnisli ; siinkcMi (lycs, \\\\y\\ ("ever, f.';rciif, l.-isHitiidc, tn tlicday ;i,fV(M' .()° F. She was confined to her bed I'or five days. The fathei', forty-nine years old, was .seized with the same symptoms in twelve to thirteen hours, and had also headache, pain in the joints, thirst, and inability to walk. The tongue was dry, the pulse rapid and small, and the pupils reacted slowly. He was sick eight days. The mother, who ate but little, was seized sud- denly in the night with vomiting, and such great dizziness that she was unable to walk without holding on to the furniture. A boy, under two years of age, was seized in the night A\ith vomiting and violent diar- rhoea, which soon became bloody. The stools Mere unusually offensive, and persisted so for several days. He Mas sick nine days. Three other children, M'ho ate but very little. Mere sick tMO days Muth slight abdominal pain and diarrhoea. No material M'as obtainable for exami- nation. The butcher said that the kid Mas apparently healthy, but the mother declared that the meat around the joints of the hind legs M-as verv soft and M-atery, and the joints themselves enlarged (septic poly- arthritis ?). Meat Inspection and Slaughtering-. The value and advisability of thorough inspection of meats before they are placed on sale are universally conceded. In this country, under the inspection laM' of March 3, 1891, all meat intended for ex- port is required to pass a very strict system of inspection. The ani- mals are inspected before being slaughtered, and their carcasses are examined microscopically by officials of the Bureau of Animal Indus- try before being packed. The inspection of meat for local consump- tion is M'holly a matter of local authority ; some States have inspection laws and others have none ; many cities have special regulations Mhich are enforced by officials M'ho may or may not be competent through ^ Zeitscbrift fiiv Fleisch- nnd Milehbrgiene, VIII., p. ISl. 90 FOODS. proper trainiug. In Germany, the system of inspection is very rigid, particularly iu the Ciise of meats from foreign countries. This is due very largely to the activity of the agricultural interests in jirotecting themselves from outside eompetitiou ; and under the benevolent ])lea of protectiug the health of meat consumers, much care and attention are given to hunting for excuses for excluding American meiits which have already been uispected. The Federal meat inspection service is, according to Salmon,' a sanitarv rather than a commercial inspection, apjilied not alone to meats for export, but also to those intended for inter-state commerce. Curiously, however, the very important inspection for trichinae is pri- marily a commercial matter, being applied only to pork intended for shipment to certain foreign countries which require it. The United States inspectors are instructed to condemn all female animals in an advanced stage of gestation, and to prevent their slaughter for food, Salmon ruling that, though " the animal is, strictly speaking, iu a physiologic condition, it is not in its usual physiologic condition, nor is the change one which is calculated to improve the quality of the meat." Females in which parturition has recently occurred are like- wise condemned as nnfit for food. Many animals are condemned on account of bruises and injuries received on their way to market ; during 1900, there were condemned for this cause, in round numbers, carcasses or parts of carcasses of 4500 cattle, 1,000 sheep, and 12,300 hogs. In some of these, the injuries were extensive, sometimes complicated with abscesses, septic infection, and gangrene. At the end of 1908^ it was estimated that Federal meat inspection covered slightly more than one-half of the entire number of animals slauo^htered for food in the United States. The followinsj: table shows the diseases and conditions for which condemnations were made on post-mortem inspection for the fiscal year 1909.^ CatUe Calves. Swine. Sheep. Go.als. Cause of coaderauation. Car- casses. Parts. Car- casses. Parts. Car- Parts. Car- casses. Parts. Cnr- Parts. Tuberculosis Actinomycosis 24,525 589 40,148 44,440 177 151 69 45,113 20,789 7,173 6,329 1,623 791,735 21 676 1,479 862 1,023 102 107 763 5,714 1 7 37 129 5 3 8 18 8 4 41 1 Sep)tieemia, pyemia, and uremia Pneumonia, pleurisy, enteritis, hepatitis, nephritis, metritis, etc Icterus 845 1,418 60 427 523 295 45 775 Texas fever Caseous lymphadenitis .... Tumors and abscesses Pregnancy and recent partu- rition Injuries, bruises, etc Immaturity 107 254 2,261 5,989 'l,'941 28 34i 4,376 43 132 1,178 89 372 1,031 3.215 1,609 3,842 2,114 1 Sexual odor Miscellaneous 4,617 7,221 1,653 14 Total 35,103 99.739 8,213 409 86,912 799,300 10,714 170 82 1 ^ Jouraal of the American Medical Association, Dec. 28, 1901, p. 1715. '' Report of the Chief of the Bureau of Animal Industry, 1908, p. 5. 3 ibid., 1909, p. 20. In inspcc^liiifr mcnis, s|)(H;ijil ;il(ciilioii .sli(»iil(l he paid to flic fonncclivc tlHHiK^ iiiid ;;l;iiic sweet, uiid llic tii(';ii slioidd cdiiiiiiiiiiicilc no iiii|ilc;isant stiicll to a wrxtdcii Hkovvcr lliriisl inlo il, aixl wil lidiviw n. The iriii>clc slioidd Itc firm and eluHtic!, Will not loMt;li. Any \aii;ilion I'loni lli<- n;itni':d color slionld !)•; rejj;iir(lcd wilJi siis|)ici(>ii, wry dark (lolor siif^^;cstinjj; lcl»rilc condilioii, or llial, (lie animal was wot slanj^litered, or was sian^-lilcrcd in a dvinj; condition, Sncli meal iMidci'ijocs dcconipo.-iiioii nmcji moi'c rajtidiv than noi'inal inc^ai. Animals llial lias'c \n-r\\ drowned or liavc heen killcul by acicidenit withont heinj^ hied yield a dark and discolr»re«i meat that, is likely to decompose more; rapidly than that of animals that have rej^idarly heen slannhtcred, hnt an animal that has Ix-cn injnrcd, hnt, not killed, may he slaMt;'litercd, propei'K hied and dres.-ed, and its meal, i,s then |)er(eetly L!,'ood. 7\nimals should he kept without food lor at least twelve hours before sla.iif>'hter, and tlu! (carcasses should he hiuiu' (in- a nundier <»f' lionr.s to cool. Many diseases are indicated more clearl}- alter the body luw cooled. The Jewish method of slaiisi^hterinu; is rcg'arded by many as far superior to any other. Aeeordino- to Dendx),' it is the most nitional from a hygienic stand])oint, since the animal is hied rapidlv and com- pletely, and the convulsive movements cause the meat to be more tender and of more attractive appearance. I^actic acid is develo])cd, and through its chemical action on ])otassium jihosphate, ])otassimn lactiite and acid ]>hosphate of potassium are formed. 'J'he latter hinders the development of micro-organisms, delays tlie formation of ptomains and other poisonous matters, and improves the taste, lligor mortis comes on more quickly, and the meat is, therefore, more quickly available for use, and also will keep several days longer than ordinarily. A process of slaughtering originating in Denmark appears to have borne the test of a hard tlu'ee-months' trial in a very satisfactory manner, and recommends itself for adoption in the tro])ics, where meats decompose with exceeding rapidity. The animal is shot in the forehead and killed or stunned, and as it falls, an incision is made over the heart and the ventricle is opened for two juii'poses : to allow the blood to esca]>e, and to admit of the injection of a solution of salt through the bloodvessels by the aid of a poAverful syringe. The process requires but a few minutes, and the carcass may be cut up at once. EGGS. Eggs form a valuable substitute for meats, being fairly rich in fats and proteids, and are well adapted to the stomach of the invalid and convalescent when meats cannot be borne. The nutritive part of the white is practically limited to proteids, which amount to about 12 per cent. ; the yolk is richer in proteids, and contains in addition about 33 ^Deutsche Vierteljabi-schnft fiir ol^t?ntliobe Gesundheitspflefre, XXVI., p. 688. 92 FOODS. per cent, of fat. The albumiu of the white is in a condition of sohi- tion in cells with very thin walls. The fatty matters of the yolk are in a condition of emulsion, being held in suspension by the vitellin. The entire yolk is held together by an enveloping membrane and is sus- pended in the white, being hold in position by an albuminous band at either end : The following table by Langworthy ^ shows the average composition of eggs of different sorts : Hen: Whole egg as purchased .... Whole egg, edible portion . . . White Yolk Whole egg boiled, edible portion White-shelled eggs as purchased Brown-shelled eggs as purchased Duck: Whole egg as purchased .... Whole egg, edible portion . . White Yolk Goose : Whole egg as purchased .... Whole egg, edible portion White Yolk Turkey : Whole egg as purchased .... Whole egg, edible portion . . . White Yolk Guinea fowl : Whole egg as purchased .... Whole egg, edible portion White Y'olk Plover: Whole egg as purchased .... Whole egg, edible portion . . . Evaporated hens' eggs Refuse. Per cent. 11.2 10.7 10.9 13.7 14.2 9.6 Water. Per cent. 65.5 73.7 86.2 49.5 73.3 65.6 64.8 60.8 70.5 87.0 45.8 59.7 69.5 86.3 44.1 63.5 73.7 86.7 48.3 60.5 72.8 86.6 49.7 67.3 74.4 6.4 Protein. Per cent. 11.9 13.4 12,3 15.7 13.2 11.8 11.9 12.1 13.3 11.1 16.8 12.9 13.8 11.6 17.3 12.2 13.4 11,5 17.4 11.9 13.5 11.6 16.7 9.7 10.7 46.9 Per cent. 9.3 10.5 2 33^3 12.0 10.8 11.2 12.5 14.5 .03 36.2 12.3 14.4 .02 36.2 9.7 11.2 .03 32.9 9.9 12.0 .03 31.8 10.6 11.7 36.0 Per cent. 0.9 10 .6 1.1 .8 .6 .7 1.0 .8 1.2 .9 1.0 .9 .8 1.2 .9 1.0 3.6 Fuel value per pound. Calories. 635 720 250 1,705 765 675 695 750 860 210 1,840 760 865 215 1,850 635 720 215 1,710 640 755 215 1,655 625 695 2525 The proteids of eggs have been studied by Osborne and Campbell,^ who found that the yolk contains a large amount of protein which resembles a globulin, but is believed to be a mixture of compounds of protein matter with lecithin. The proteids of the white were found to include ovalbumin, ovomucin, ovomucoid, and conalbumin. Eggs contain a certain amount of sulphur, to which the staining of silver spoons and the odor of rotten eggs (hydrogen sulphide) are due. The rotting of eggs is supposed to be due to the admission of fermenta- tive micro-organisms through the pores of the shell, or to those already present before the shell is formed. It is a commonly accepted idea in some parts of the country that eggs with brown shells are of greater richness than others, and that the degree of richness is directly proportionate to the depth of color. In some markets, on the other hand, the white egg is held in higher esteem. ^U. S. Department of Agriculture, Farmer.s' Bulletin, No. 128 (1901). * Report of Connecticut Experiment Station, 1899, p. 339. EddH. 93 According to \\\i\ rc^siill.s ofjiii (!xfx!H.siv(! sfiidy of I Ik; clicrnicjil roiiipoHi- tion of ((}j^f^,s curried on iii (Ik; (/nliloniiii 10x|)(;rim(iil SImiIod miiinlv for tli(^ jmrposc ()(■ ddrcniiiiiiii^ wliiii didri'ciiccs, if" any, exist betwc'eii (licrn, tliere is no luisis ol" (act (or IIk; |)(»|»ular Ix-lief". Jn fact, (lie very hiiglit difforcnecM noted were in (';i\(»r of the ulille c^^s, hiii tli<' average dif- ferences Ix'tween llie two kinds wen; less than tlie fliict nat ions hetweon individual specimens of the same ^ronp. 'I !)<• (ij/nrcs fthtained arc ])i'es(Uit('.d in the (oliowin^- table taken IVdhi i'ainuM^' I5ulletin No. 87 :' ANALYSIS OF BKOWN Sil KIJ,i;i) AM) W F[ITJ!>flHELLP:i) EGGS. Brown-shelled eggs : Yolk White I'^utire egg W hilc-shdU.d eggs : Yolk ." . . White Entire egg Water. Per ct 49.59 86.60 65.57 49.81 86.37 64.79 Protein. Per ct. 15.58 11.99 11.84 15.49 12.14 11.92 Fat. Per ct. 33.52 .21 10.77 33.34 .35 11.22 A8h. Per ct. 1.04 .54 .64 1.05 .56 .67 Shell. Perct. 10.70 ToUl, Perct 99.73 99.34 99.52 99.69 99.42 10.92 I 99.52 The question of influence of breed on composition has been investi- gated at the Michigan Experiment Station. The results .showed that the variations in composition are too slight to be of practiad value, and, as with the brown and tlie Avhite eggs, so slight as to be le.S'^ than the variations between individual specimens from the same l)rees formed. A small amount of lard, dissolved in a mixture of ecjual j)arts of alcohol and strong ether in a test-tube and allowed to .stand in a cw)! place, will, when the solvent in large part is evaporated, show masses of crystals, which, on examination under the microscope, are seen to be rhombic and extremely varialile in size. Beef stearin, sinn'larly treated, shows fan-shaped and dumbbell-shaped clusters of needle cr}'stals. Mixtures of pure lard and beef stearin will show both forms of crys- tals. Sometimes, when crystallization ])roeecds rapidly, the crj'stals from pure lard an^ extremely small, and are clustered in such a way as to be distinguished from beef stearin crystids only with great difficulty. It is essential that the crystallizing process shall proceed slowly, and that the amount of lard dissolved in half a test-tube of the solvent shall be quite small — not larger than a large pea. The mouth of the test-tube should be stopped with cotton. Section 3. MILK AND MILK PRODUCTS. MILK. United States Standard. — Standard milk is the fresh, clean, lac- teal secretion obtained by the complete milking of one or more per- fectly healthy cows properly fed and kept, excluding that obtained within lifteen days before and ten days after calving, and contains not less than 8.5 per cent, of solids (not fat) nor less than 3.25 per cent, of milk fat. ISIilk is a solution of sugar, mineral matter, and proteids, with other proteids and fat in suspension. Its composition is very variable, not alone as between difterent species of mammalia by which it is produced, but as between different individuals of the same species. Of the domestic animals, the ass and mare produce milk which most closely approximates that of woman in composition, but our chief interest in 96 FOODS. milk as au article of food in general nsc lies in that produced by cows and, to a certain extent, in that of g-oats, which is very similar in com- position. AA'hilc the comjiosition of milk of other animals than those already mentioned can have for most of us merely a scientific interest, it may be of some practical utility in the management of breast-milk to bear iii mind that the milk of animals whose diet is largelv or chiefly mejit is richest in tliose elements, the proteids, that are most conmionly at the bottom of digestive disturbances in breast-fed children. Composition of Milk. — The composition of cows' milk of average good quality may be expressed fairly in round numbers as follows : Fat 4.00 Sugar 5.00 Proteids 3.30 Mineral matter 0.70 Total solids 13.00 Water 87.0 100.00 According to Vieth, the average composition of more than 120,000 samples analyzed in England was : Fat 4.10 Solids not fat 8.80 Total solids 12.90 Water 87.10 100.00 The average of a large number of analyses made in this country showed : ^ Fat '. 4.00 Sugar 4.95 Proteids 3.30 Mineral matter 0.75 Total solids 13.00 Water 87.00 100.00 According to Van Slyke/ the average composition of about 5500 s})ecimens, examined chiefly at State Experiment Stations, was approx- imately as follows : Fat 3.90 Sugar 5.10 Proteids 3.20 Mineral matter 0.70 Total solids 12.90 Water 87.10 100.00 The milk yielded by 426 cows from private farms in Massachusetts, and by 175 more belonging to public institutions, was analyzed by 1 Experiment Station Record, V., No. 10. » Medical Record, May 25, 1907, p. 878. MILK. 97 tli(! .'iiilJior ;iii(l lii.s ;iss()c.iiil(;s, :iii.20 At ilic Piiris Miiiiici|)al I>;il)<>r;ilory - tlic following sl;iii(|;inlK arc rccogiii/tMl : Kj,t 4.00 KiiKiir •'"'•00 I'rotoids •'^•fiO Mineral niiittcr 0,70 TotJil .solida 13.30 Water ' • •_86.70 ioo;bb The following compilation 1)V Lwicli,^ from Kocnif^'s C^licniic; dcr mens. Nalir. u. (Jcnnss., ^ives tlio composition of human milk ami that of a number of ditlercnt animals : Number (if analyses. 800 200 32 47 Kind of milk. Cow's milk : Minimum Maximum Mean . . . Human milk Minimum Maximum Mean . . . Goat's milk: Minimum Maximum Mean . . . Ewe's milk : Minimum Maximum Mean . . . Mare's milk : Mean . . . Ass's milk : Mean . . . Specific gravity. Water. Casein. Albu- min. 1.0264 l.()o7(l l.OSlo 80.32 90.32 87.27 1.79 6.29 3.02 0.25 1.44 0.53 1.027 1.032 81.09 91.40 87.41 0.18 1.96 1.03 0.32 2.36 1.26 1.0280 1.0360 1.0305 82.02 90.16 85.71 2.44 3.94 3.20 0.78 2.01 1.09 1.0298 1.0385 1.0311 74.47 87.02 80.82 3.59 5.69 4.97 0.83 1.77 1.55 1.0347 90.78 1.24 0.75 1.036 89.64 0.67 1.55 Total pro- teids. 2.07 6.40 3.55 0.69 4.70 2.29 4.29 6.52 1.99 2.22 Fat. 1.67 6.47 3.64 1.43 6.83 3.78 3.10 7.55 4.78 2.81 9.80 6.86 1.21 1.64 Milk- sugar. Ash. 2.11 6.12 4.88 3.88 8.34 6.21 3.26 5.77 4.46 2.76 4.91 5.67 0.35 1.21 0.71 0.12 1.90 0.31 0.39 1.06 0.76 0.13 1.72 0.89 0.35 0.51 Constituents and Chemical and Physical Characteristics of Milk. — Fat. — The fat of milk exists in very minute globules which vary widely in size, the largest being between six and seven times larger than the smallest, but the latter are most abundant. Their average diameter is about -5-Q-V0 J"ch, Whether or not they have an albuminous envelope is a matter of doubt, the evidence for and against being about equal and of no great imjiortancc. It consists of glycerides of ten diiferent fatty acids, five of which belong to the non-volatile and five to the volatile class. The glycerides of the former group constitute by far the greater part. They are ^ The detailed analyses, with data as to breed, nature, and amount of feed, etc-, can be found in the pamphlet issued by the State Board of Health : Eesult.< of Inquiries Relative to the Quality of Milk as Produced in Massachusetts. Boston, February, 1SS7, - Hygiene Generale, 1907, p. 303. 3 Food Inspection and Analysis, 1909. 7 98 FOODS. steariu, palmitin, olein, myristiii, and butin ; the two last are present in very uiinute amounts. Those of the latter group give the charaeter- istic butter tlavor. They are butyrin, caproin, caprylin, caprin, and laurin ; the first two are the important ones, and together amount to over 7 per cent, of the whole fat ; the three others are present in but insignificant traces. The fat, being the lightest part of milk, tends to rise to the surface when the milk is allowed to stand, and then forms a layer which we know as cream. This contains not fat alone, but all of the constituents of the milk, and is, therefore, simply milk « containing an excessive amount of fat. It is a common error to regard the depth of the cream layer which forms on standing a given length of- time as an infallible measure of the richness of the milk by which it is yielded ; but cream does not always rise well in rich milk, even after standing more than twenty- four hours. The author repeatedly has found the percentage of cream thrown up by a specimen of milk in a 100 cc. graduate in twenty -four hours, as measured by the lines of graduation, to be less than the actual percentage of fat as shown by analysis. The rapidity with which the fat finds its way to the surface depends largely upon the size of the fat globules. The largest rise first, and the very smallest may not rise at all. Again, a watered milk throws up its fat more quickly than a normal specimen, although it does not contain as much. Furthermore? according to Rosenau,^ heating of milk for one-half hour at 150° F. (65° C.) prevents entirely the rising of cream, or very materially delays it. It appears, therefore, that a milk of inferior grade may under some circumstances show a deeper cream layer than a milk of unusual richness. Generally speaking, however, a rich milk will usually show its quality on standing. The first part of a milking is always poor in fat, the middle portion contains about the average amount of the whole, and the last portion is always the richest. The first portion is known as " fore-milk," the last as " strippings." A specimen of " strippmgs," analyzed by the author, gave the following results : Fat 9.82 Sugar 4.00 Proteids 4.21 Ash _0^ Total solids 18-82 Water 81.18 100.00 Milk-sugar. — Lactose or sugar of milk, is peculiar to milk. It is much less soluble in water than dextrose and sucrose. Heated to 100°-131° C, it becomes changed in color to brownish, and at higher temperatures loses water of crystallization and undergoes further change. At 175° C, lactocaramel is formed. When heated in solution, in milk 1 Hygienic Bull., No. 41, 1908. MILK. y.i itn(;ir, for nbiiriH boll) siilphtir Mild |>lios|)horiis, .-iiid is in iiif iiiinic coinbiii.'ifioti with eal- (^iiim plios|)li;ir('. Il is not coii^iiIjiIccI b\' hc;i(, but i~ pn'cipit;it<'d bv acids, by whicli tlic coiiibiii;iti'iii is broken up. In llie prcscne*' of lactic a.ci(l in siiimII aiiioimts, dne (o llie bicikinL' np of Inetosc, coa^i- latioM is liastoiicd by tlu; ;i|»plie;il ion of ticnlle lii;it. 'I'lii- plienomcnon Is observ(!d very (commonly in tiio case of milk wbieli to tlic tast<; Is aj)p!ireiitly swec^t, but vvliieb is "just on tbc turn." The chief j)art of tiie reinaind(!r of the proteids is laet;ilbuiniii. This is coa.^uhitcd by heatiii}^ to 65°— 7.'>° C, but not by dilute acids. It coutains sulj)hur, but no phosj)horus. In amount it ranp^cs from 0.2 to O.S j)er cent. It is inneh more abundant in colostrum. Tlu; re- maining proteids an; lacto^lobulin, which is ('oaguiated liy heat; lact<^)- protcin, coagulablo by neither heat nor dilute acids, and filtrin. lOadi exists in but very small amounts. Mineral Matter. — The mineral matter contained in milk consists of phosphat(\s and chlorides of ])otassium, sodium, calcium, and magnesium, and extremely minute traces of iron, (^f the bases, potassium is the most abundant, with calcium, sodium, and magnesiiun in the order given. The phosphates predominate over the chlorides. Part of the calcium exists in combination as phosphate with the casein, and the rest, according to Danilcwsky,^ as mono- and tricalcium phosphate and in combination with citric acid. Part of the magnesium, also, exists in combination with citric and other organic acids. In very small amounts, these are normal constituents of milk of various animals. In human milk, citric acid is present to the extent of about 0.05 per cent., and in cows' milk, it is about three times as abundant. Specific Gravity. — The specific gravity of cows' milk of normal com- position ranges from 1.029 to 1.034. It increases very slightly for about five hours after the milk is drawn, and then becomes stationary. The increase is believed to be due to molecular modification of the casein, and not to the escape of gases. It is lowered by fat and water, and by tlie presence of bubbles of air, and is raised by removal of cream. Reaction. — When freshly draAvu, milk shows the so-called amphoteric reaction ; that is, it is acid to litmus and alkaline to turmeric. The alkaline reaction is intensified on warming, but the acid reaction is not influenced thereby. On standing, the alkaline reaction is overcome by the lactic acid which is formed gradually from the sugar, and the acid refiction is increased in consequence of the same. The original acid reaction is due to the presence of carbonic acid, acid jihosphates, and diealcium caseinogenate, the alkaline to alkaline carbonates. Human milk is normally alkaline, and that of carnivora is acid. Appearance. — The appearance of normal milk is too familiar to need 1 "Wmtsch, 1001, p. 549. 100 FOODS. description ; but under certain rare abnormal conditions, milk may assume dilierent colors, iucluding blue, yellow, violet, and red. These changes of color are due to the action of certain bacteria, and are always evidence of unsanitary conditions to which the milk is exposed at the dairy or during distribution and storage. Blue milk is due to the action of B. cyanogcnea, Avhich produces a blue color in no other food material. For its development it rcipiires the presence of lactic ferments, and, therefore, has no effect on milk that is sterile. Another organism capable of producing the same effect is B. cyaneofluoresccns. A red color may be caused by B. prodigiosus, B. lactis crytlirogcnes, Sarcina rosacea, and by blood. Yellow milk is caused by B. synxan- thus and a number of other organisms. Like B. lactis ei-ythrogenes, B. synxanthus produces the abnormal coloration only after coagulating the milk and dissolving the curd. B. lactis erytJirogenes causes red color only when the milk is kept in darkness ; in the light it causes a yellow color. A violet color is produced by B. violaceus. All of these milks of abnormal color are, aside from their uninviting a])pearance, unfit for food, since they are likely to cause gastro-intes- tinal irritation. Thus Eichert ^ records a case of severe diarrhoea, with very offensive stools, in a child of nine months, due to red milk caused by a bacillus (probably B. lactis erythrogenes) present in the milk- ducts at the time of milking. Taste. — The flavor of milk is modified very sensibly by the char- acter of the feed and by the absorption of gases and volatile matters of all kinds. It is affected very readily by turnips, garlic, wild onion, mouldy hay and grain, distillery swill, and damaged, rotten ensilage. A very marked taste, suggestive of turnips, is more commonly due to B. fcMidus lactis and related species than to turnips. This organism causes also other disagreeable tastes, including sweet, bitter, and putrid. Bitterness of taste may be due to various weeds, chiefly cruciferse, or to bacteria. When due to feed, the taste is bitter from the very first, but when caused by bacterial agency it develops some time after milk- ing, when the organisms which produce it have had opportunity to produce peptone from the proteids. It may be due to inflammatory conditions of the udder, in which case it may or may not be noticeable when the milk is freshly drawn. The bacteria concerned in producing bitterness may exist in ducts of the teats, or may come from stable filth. Among them may be mentioned Micrococcfiis C'omi, Micrococcus casei amari (Freudenreich), B. liquefaciens lactis amari (Freudenreich), B. Fli'igge, and, in addition, various yeasts. A soapy taste, sometimes also sweetish, may be caused by various bacteria, including a bacillus found in hay and straw, discovered by Weigman, capable of producing its effects within 24 hours ; another, isolated by Eichholz, which causes first a sweetish soapy taste and then one suggestive of cow manure, and grows well at a temperature below 50° F., at which the lactic acid bacteria are inhibited ; and B. saponacei. 1 Zeitschrift fiir Fleisch- und Milchhjgiene, VIII., No. 5, MILK. 101 A |niiri(l taste i.s cauHcd Uy /!.J'"/iihn^ hit-tin and a, niiinhcr of ot!i(;r .s|)(!(;i('.s. A HiiUy tasto may Ix; note*! in tiiilU coiitjiiiiii)^ j»iih ; HoriK,- tiiiics it is (Ia)i;rc(al)lo tastes, as nily, fisliy, aiij eertain actual hiolojj^ie, propctrties, wliic^li are destroyed Wy expfwure to liif^li ternperatJircH, among tlieni heing tlu; j)ower said to he |io.'-HeHHeiLory and bacteritiidal for 3 hours, and partially inhibit^jry for 9 hours more. The existence of this bactericidal |)roperty has, howfiver, been repeatedly denied. Acciording to Klimmer," neither human nor asses' nor cows' milk possesses bactericidal j)ower against saprophytes, B. coli and B. typJio.siis. According to Stocking^ the ascribed jjroperty may be ex- plained by the fact that certain species of bacteria which find in milk no suitable food material die out more or less rapidly. Kolle and others ^ found an absence of bactericidal power against B. cod, B. tj/- phosus, B. paratjiphoi^m, and some other sj^ecies ; but B. dyHcnteruB was inhibited and cholera sj)irillfe were partly killed. Koning,* how- ever, states that the bactericidal property ajjpears soon after the milk is draAvn, and exists in esjiecially marked degree in colostrum. B. coll, B. fiuorescens liq., B. ackli facfiei, and other species are destroyed ; and colostrum acts with especial vigor against B. coli. Hippius,* twn a.s liic,ti(! ((iriiicnts, vvliifli convert. lli. ladU acidi (Ivcicibmaiin), and, accordin{>; to IFcincMnann/ at^rces morpholof^ically and culturally with Sfrcj>f.()C()cciis pi/oi/ciics. indeed, by passai^e thronL;;h a scries of rabbits, lleinemann succeeded in raising its virulence from praeti(;;dly nothing to that of the latter species. N(!xt in im))ortan(!e is B.acldl ladicl (TTiiepjic), which is apparently identical with I>. /dcfis (icro posHcs.s no par- ticular advantatjjc! iu dairies wlicre cleanly inetliodH arc followwl. Tbe dilferenec in the number of biiefcria \vhi(;h fall into milk whr^n pr()|)(ir preejuilions -.wv. observe(| and when ihcy arc ne^deeted is ver\' considerable. Thus, Soxhiel lunnd I hat the milk of a cow with a dirty udder, stalled in a dirty slabh;, ke|)t sweet 50 hours at ordinary tem- p(!ratin-e, and tlint, when luir u(ld(!r was washed and she was milked in the ojx'n air, it remained sw(!et a day and a half lon^^.p. Still more instructive are the results obtained by Freeman,' who ex|)osed j)latex, 3.5 inches in diameter, for two minutes as follows : one in the ojh'Ii air, one inside a, barn, and a third in front of the milk \)ni\ und<;r a cow in the same barn while bein«r milked. The first ])latresent after ]H hours in milk kept at (iH'" l'\ When milk is ieed the bacteria orii^dnally |)rcsent decrease in number for a lonj; tim<', and since the low temperature prevents the lactic ferments from mul- tiplying^ and gaining ascendency over the other species, the latter show a relative increase over their nundicr in milk which is kept at higher temperaiunvs. After the ])eriods of inhibition and slow growth have passed, the lactic acid bacteria grow with extreme ra])idity, and as they multiply other species, and finally practically all others, disapjiear. Conn and Esteu state that the lactic acid bacteria sometimes are 99 per cent, of all present. It is on account of the beneficent action of these bacteria against those which in their absence cause putrefactive changes that ordinary connncrcial pasteurization of public milk su])- plies is objectionable, for stale milk may thus be kept a long time with- out curdling, and meanwhile deleterious changes are being caused. Many species of milk bacteria can grow below 40° F., and they grow more rapidly after several days' exposure has enabled them to become habituated and to adjust themselves to the unusual condition. Thus a milk which has not been subjected to artificial heat may become unwholesome, although sweet and apparently wdiolesome. According to Conn, it is not unlikely that this may be the explanation of some of the eases of ice-cream poisoning so commonly observed in summer, the cream being kept at a low temjierature for days, until considerable is accumulated or demand arises, and then the product when made is rich in bacteria of a sus}>icious character. To a poisonous substance isolated by Professor Vaughan, and shown to have been the cause of the train of symptoms commonly known as ice-cream poisoning, milk poisoning, and cheese poisoning, the name tyrotoxicon Avas given by its discoverer. The influence of different temperatures on the rapidity of bacterial multiplication is well shown by Park's results, obtained after allowing portions of the same specimen to stand under otherwise similar con- ditions. At temperatures below 50° F. there was at the end of 24 hours no increase — in fact, a decrease — in the number of bacteria ; but at higher temperatures the multiplication was enormous. The original number per cc. was 3000, and the growths at the several temperatures above 55° F. were as follows at the end of 24 and 48 hours : 1 Starr's Agricultural Experiment Station Keport, 1901, p. 13. 1V2 FOODS. Temperature. 24 hours. 48 hours. 60° F., 180,000 28,000,000 68° R, 450,000 25,000,000,000 86° R, 1,400,000,000 94° R, 25,000,000,000 Milk of fair quality from a shop was kept at 90° F. for 8 hours, during M'hich time its contained bacteria increased from 92,000 to 6,800,000 per cc. ; another, of poor quality, under the same conditions, showed an increase from 2,600,000 to 124,000,000. As the lactic acid bacteria multiply, they seize upon more and more of the milk-sugar and convert it to lactic acid, the amount of which is expressed in degrees per 50 cc. of milk, one degree representing the amount neutralized by 0.5 cubic centimeter of decinormal sodium hytlrate, which is 9 milligrams. When milk contains so much lactic acid that 50 cc. are neutralized by 22 cc. of the reagent, it begins to taste sour ; and when 42.5 cc. are required it is ready to curdle. That public milk supplies frequently show millions of bacteria to the cubic centimeter is notorious, and both in this country and in Europe it is common to find that in some large cities the sewage is less rich in bacteria than the milk supply. Proskauer^ and others, for example, found the market milk of Berlin to average 3,500,000 in summer and more than 500,000 in winter ; Newman has reported the following aver- ages for London (city), Westminister, Halborn, Islington, and Fins- bury : 4,800,000, 1,600,000, 4,800,000, 1,600,000, 2,300,000 ; Jor- dan's averages for Chicago market milk during April, May, and June, 1904, give a general average of 12,785,000. The milk of cows with garget, an inflammatory condition of the udder, the commonest of all bovine diseases, may have a far more extensive bacterial flora than that of ordinary milk. The exciting cause of this abnormal condition appears to be no single organism, but various species, among which are Staphylococcus aureus and aJbus, Staphylococcus viasti- tidis, Streptococcus mastitidis, Galactococcxis fulvus, B. coli, B. aerogenes, and B. pyogenes hovis. Several of these species may be present in the same udder at the same time. In such milk pus is always present with the bacteria and in such amounts as to cause a salty taste. The disease may be present without any perceptible symptoms, and attention may be called to it only by the appearance of caseous masses or shreds on the strainer ; hence the product of the most conscientious dealer may be extensively infected with the causative organisms and pus, in spite of all precautions and without his knoM^edge. The presence of streptococci in milk does not necessarily mean the existence of garget, for they have repeatedly been found in healthy udders. Reed and Ward ^ have recorded the case of a cow, of the Cornell University herd, apparently healthy, whose milk yielded strep- tococci at intervals extending over two years and a half. When she was killed the udder showed the organisms in abundance. 1 Zeitschrift fiir Hygiene und Infectionskrankheiten, LVII., 1907 p. 173. 2 C^ntralblatt fur Bakteriologie, XXIX., 1901, p. 496. MILK. llo Wlwdlicr or ii()(, f'roin (lisciiscd udders, rimiiy iiuMi'' milk Mipplics will yi(!l(l a \:\v\rv |)r<)|)()rl,i()ii oC sjimplrs in wliidi strcptMCMc. i ;irc |)rc.'-<'iil in l;i:r^(! nnmlx-rs. TIiiim, l^/i.stcs ' diseovcrt'd tliciii in KXi <»(" I H(i ,>-;nn|)l«!K (•X!Uiiin<'(l ; I'x-ck, ^ in .'}r> <»rr)(; s:nM|.lcs i.f (lie I'x ilin ^n|.|.ly ; J><-r^cy,'» in 20 of 10 Siiniplcs oC ni;iri of r>9 sinnplcs IVoni (irst-cliiss diiirics ; K;iiscr,' in 7ation of the udder when empty. Bergey's statements are endorsed by Trommsdorff," who found that I Britisb Medical Journal, Nov. 11, 1899. ^ Deutsche Vierteliahisscbrift fiir iiffentliche Gesundheitspflege, 1900, p. 430. 3 American Medicine, April 20, 1901, p. 122. * Archiv fiir Hygiene, LYI., 190(i, p. 51. ^ Jotirnal of HvCiiene, VI., 1906, p. 12,*^. 6 Arch. f. Ilyg.," Miinchen u. Berl., 1910, Ixxii, 91-158, 1 pi. ^ Journal of Infections Diseases, 1907, Suppl. 3, p. 63. 8 British jNIedical Journal, 1905, p. 1165. '■' Archiv fiir Hygiene, LIX., 1906, p. 224. ^^^ I'niversity of Pennsylvania Medical Bulletin, Sept-, 1907. II Miinchener medizinische Wochenschrift, LIII , Xo. 12. 114 FOODS. whenever leucocytes were present iii large numbers innumerable strepto- cocci were also j)resent. Miller ^ comes to the following conclusions : (1) Many leucocytes and streptococci are present in the normal milk of a healthy cow. (2) Leucocytes and stre]>tococei are, as a rule, more numerous in the milk of diseased than in^that of healthy cows. (3) As an aid to veterinary inspection, the number (^f leucocytes may furnish some information of value. If a dairy milk shows an unusually higli leucocyte count, a special examination of the herd for garget, etc., should be made. (4) No satisfactory method has been devised for distinguishing the pathogenic from the non-pathogenic streptococci in milk. Their sig- nificance is, therefore, a matter for further study. (5) In view of the recent researches upon streptococcus lacticus, no constant relationship may be expected between the number of strepto- cocci and the number of leucocytes in milk. Preservation of Milk. The keeping quality of milk is influenced by cold, which retards the growth and multiplication of bacteria which bring about decomposition ; by heat, whicli destroys them ; and by chemicals (antiseptics), which either kill them or retard their growth. Cold. — Preservation by cold is, in many respects, preferable to either of the other methods. The constituents are in no way altered in character, there is no change in digestibility, and no element is in- troduced into the system with the milk to exert any harmfid influence upon the digestive processes. In places where ice is expensive or not obtainable, this method is not available, but where it is cheap and plentiful, it is the one in most common use. In some parts of Europe milk is frozen into solid blocks by the ammonia process, and shipped in that form to market, or sent in large air-tight cans, into each of which a block of frozen milk, weighing about 25 pounds^ is placed, to keep the milk in which it floats at a low temperature. Heat. — Pasteurization and Sterilization. — By pasteurization is meant raising the temperature of the milk to such an extent and for a suffi- ciently long period as to ensure the destruction of the lactic acid bac- teria and pathogenic organisms without afl'ecting the enzymes or the lactalbumin. As regards the thermal death points of various bacteria, writers have not been in agreement, but the results of Rosenau ^ are in accord with those of Yersin, BonhoflF, Schroeder, Theobald Smith, Russell and Hastings, and Hesse, and are as follows : The tubercle bacillus in milk loses its infective properties for guinea- pigs when heated to 60° C. and maintained at that temperature for 20 ^ .Journal of Comparative Pathology and Therapeutics, London, March, 1909, p. 34i Vol. XXII,, Part 1. 2 Pediatrics, 1908, p. 549. I'lllCHKILVATION OF MILK. 115 rniniltcH, or at (ir)*^ (). for "a \n\\r\\ slioi-tcr time" 'I'lic typlioi*! hufil- lus i,s killed iC Hiihjcftlcd (o GO" (/'. for '1 miiinlcs, 'I'lic j)reci;d)ly affect the chemical ])roj)erties of milk. In connnercial |)iisteurization a number of dilfcrenl tyjies of ,'i]»j)a- nitus are (!nj|)loycd and different methods aic. followed, the teinperatures ran<2;ing from 150° to 185° F., or even higher, and the periods of ex- posure from less than a minute to as much as an hour, with immediate coolint]:; thereafter, in order to ])reserve the flavoi' and to inhibit the growth of the surviving bacteria. Temperatures higlmr than 158*^ Y. cause milk to ac(piire a "cooked" flavor, which to many persons is unpleasant. By raising the temperature to the ])oiling-point, milk is more com- pletely sterilized than by the processes employed in j)asteurization ; but absolute sterilization cannot be accomplished cxcej)t i>y boiling on suc- cessive days or by continuous heating under pressure for at least 2 hours at 248° F., on account of the very resistant nature of the s])ores of various species of bacteria commonly present in milk produced under the usual conditions. According to Rosenau,^ boiling produces decomposition of ])roteins and other complex nitrogenous derivatives ; diminution of organic phosphorus ; increase of inorganic phosphorus ; precipitatif)n of cal- cium and magnesium salts and the greater part of the phosphates ; ex- pulsion of the greater part of the CO^ ; caramelization or burning of a certain portion of the milk-sugar (lactose), causing the l)rownish color; partial disarrangement of the normal emulsion and coalescence of some of the fot globules ; and coagulation of the serum, which begins at 75° C. Casein is, furthermore, rendered less easy of coagulation by rennin, and is slowly and imperfectly acted upon by pej^sin and pan- creatin. A cooked taste is caused by boiling. Cream does not rise well, if at all. Formation of a scum begins at 60° C. Heating kills the ferments in milk. These can stand (30° to 65° C. for some time. Thev are weakened by 65° to 70° C. They are destroyed at 75° to 80°" C. Sterilization at higher temperatures causes still further changes in the proteids, and converts part of the lactose to caramel. Objections to Pasteurization and Sterilization. — So flir as children old enough to receive a mixed diet and adults are concerned, there are no objections on the score of develojMuent and health to the use of pasteur- ized and sterilized milk, and, indeed, where it is difficult or impossible to secure a clean and wholesome milk supply, pasteurization is a com- mendable and logical procedure ; but, on the other hand, against the 1 Pediatrics, 1908, p. 5-47. 116 FOODS. use of pasteurized and sterilized tnilk for bottle-fed infiints and against the substitution of connnercial pasteurization for the enforcement of the strictest dairy hygiene, there are very valid objections. It is, first of all, to be recognized that proper jiasteurization is, in a sense, a labor- atory process, which requires considerable skill in bringing every part of the volume o})erated upon to the requisite temperature and not be- yond it. With insufficient heating the object of the process is not accomplished; with excess of temperature the biological properties of the milk, residing in the ferments or enzymes, are destroyed, and the milk is made an unfit food fov infants. Even with the best of care, untoward results of continued feeding of infants with pasteurized milk have been so frequently observed, in both private practice and insti- tutional experience, as to demonstrate a real danger. Sill ^ relates that of about 25,000 infants that came under his charge in 5 years, those that were fed on pasteurized or sterilized milk continuously, or part of the time on the one and part on the other, no less than 97 per cent, developed rickets or scurvy, or a conibination of the two. Those that were fed partly at the breast and 5 feedings per day of heated milk had the same symptoms in a lesser degree. Sterilized milk was given only during the 3 summer months, and pasteurized milk at other seasons. Infants fed on raw milk were attacked with symptoms of rickets when thev were placed upon sterilized or pasteurized milk. Again, in an English children's hospital,^ a number of cases of scurvy which failed to respond to treatment led to an inquiry, which disclosed the fact that the dairy which supplied the institution had been furnishing pasteur- ized instead of raw milk, without informing the authorities ; and on the substitution of fresh raw milk the children began to improve. Ex- periments with calves and other young animals have repeatedly demon- strated the far greater and more rapid development which occurs on raw milk. Jensen ^ has shown that new-born calves fed ui)on boiled milk invariably were seized with a violent diarrhoea, similar in all re- spects to the disease known as calf dysentery ('' Kiilberruhr "). It is not, however, perfectly clear that pasteurized milk is necessarily deleterious to the health of infants. Rosenau * states that he has " made a careful compilation from the literature of the results of rais- ing children upon heated milk, and finds hundreds of instances re- corded, especially by French observers, to the effect that children flourish well upon heated cows' milk (loc. cit., p. 606). When all is said and done, the pasteurization of milk for infant feeding can neither be recommended nor discountenanced as a general proposition. The saying that ' one man's meat is another man's poison,' applies with special significance to the artificial feeding of infants." Rosenau ^ also insists, as regards the practice of pasteurization, that " we should protest against a word which means a generality and insist 1 New York Medical JonrnMl, February 8, 1908. 2 Journal of the Ameriran Medical Association, June 23, 1906. ^ Quoted by Beliring : Thenipie der Gegenwart, XLV., No. 1. ■* Hygienic Bulletin 41, p. 607. a Ann. Med. Pract., Boston, 1910, 237, j'lihSh-nvA'rfox of milk. 117 upon all ))!is<,('iiri/('(l niilU bciiij^ jn'opcrly lulx-lcd with tin- i\c\rnn'. of li(!;\i, the j)<'i'i(t- jeoted to the [d'occss. It should, Curl hcriiioic, Ih- niidc|- the iniiiifdi:it<; Sllj)ervi.sion of tiu! health olliee." A very inij)orlant ol)je(!lion to <'onntiiTci;d pastcnri/alioii (,(" pnhlif; milk snpplies is that thronu;h ihe dcs( ruction of" the l»nl slifrhllv n-si'-t- ant lactic a(n'd bacteria, wlii(th Prolessor V. C Van^han has likened to the red lanterns |)laccd as danfrer-si^nals in a hif^hway, the ino.«t eonspicnoiiH means of iiidieaf int:^ nnfitness for use is removed. Stale milk tlins deprived of tlu; ati;enls which |)rf)dnee sonrin^*-, l»nt eoiitaining the very resistant casein ferments and other haeteria wln'eh produce toxic snbslances, remains fluid and aj)parenlly wholesome for a consid- erable time, and yet may be a danjijerons food. It lias been demon- strated by Flii,ii',u;e, who as lont:; ai^o as 1H94' called affenlion to the danj^(TS of imperfectly ])asfenri/ed or sterilized milk in the feedinj; of infants, that these ])eptonizin^ bacteria may develoj) so aetiv(! a poison that pupj)ies fed nj)on snch milk may be .seized with violent and even fatal diarrhceas. Snch milk, without souring, gradually ])utrefies, but without showing by alteration in taste or appearance the damage which it has suffered through the raj)id multiplication of bacteria, winch in raw milk are inhibited by the lactic acid ferments. The older the milk before pasteurization, the greater the number of these undesirable or- ganisms and the less successful the process. Another objection to commercial ])asteurization and sterilizatiou is that these processes invite carelessness in the production and handling of milk, the acceptation of their necessity implying avoidable dirt and encouraging carelessness and negligence, the effects of Avhich can be easily corrected by the application of heat before distribution. Instead of such encouragement, there should be a general movement against the existence of the antecedent conditions which make this after-treat- ment necessary. In Massachusetts, the sale of milk which has been heated higher than 1()7° F. is contrary ^ to law, unless the vessel in which the milk is sold is plainly marked " Heated Milk." Obligatory pasteurization of public milk supplies has, in spite of various valid objections thereto, many advocates, and it has with good reason many and more opponents. That coramereially pasteurized milk is frequently excessively rich in bacteria has often been demoustratt.ss- sibility of a causal relation between their Wi^ii and th(,' great infant nK»r- tality during the hot months. E. von Behring^ asserts that the pres- ence of formalin to the extent of 1 : 4000 will not be perceptible to the sense of taste, and that nn'lk containing as much as 1 ])art in oOO is absolutely harmless. This assertion is denied by Schaps,^ who found that in still greater dilution (1 : 10,000) it causes an objectionable taste, which is still perceptible when the dilution is 1 : 40,000. He found, moreover, that although the disinfectant checks the develojiment of the lactic ferments, it has much less effect on staphylococci, intentionally intnxluced, even when the proportion is 1 : 5000. While a marked inhibitory influence is exerted u]X)n milk bacteria by formalin in pro- portion of 1 : 5000 or 1 : 10,000, ^vhen the milk is kept at 50° to 60° F., Sommerfeld* found that it has hardly any influence after twenty-four hours M'hen the milk is kept at 68° F. At incubator temperature the treated milk yielded about the same number of bacteria as the controls. Typhoid and dijihtheria bacilli in sterilized milk con- taining 1 part of formalin in 5000 resisted the disinfectant when the mixture was kept at room temperature for 24 hours and at incubator temperature for 48 hours. According to Kolle,'' while formalin added to milk to the extent of 1 : 25,000 or 1 : 40,000 extends its commercial life after 3 days, the milk bacteria multiply greatly without causing any change in con- sistency, because the souring bacteria are inhibited ; and although path- ogenic organisms diminish in number more rapidly in such milk than in untreated milk, their pi'esence may be detected even after 5 days. Moreover, in addition to the deleterious influence of continned inges- tion of small amounts of formalin one must bear in mind the fact that 1 The Lancet, Nov. 11. 1899. ' Therapio der Gesyenwart, XLV., Xo. 1. 3 Zeitscbiift fiir Hvtriene und Infectionskrankheiten, L., p. 247. 4 Ibid., p. 153. ^ Klinische Jahrbiicher, 1904. 120 FOODS. foi'inalinized milk may become a dangerous food tlirougli the persist- ence in it of tlie more hardy peptoui/ing bacteria. JJandini ^ finds that formaldehyde tends to prevent the action of rennet, the influence being greater the larger the period of contact and the larger the amount added. Lowenstein - asserts that the interference with the action of rennet is due not to any destructive influence u])on the enzymes, but to changes caused in the constitution of the casein. Carbonate of Sodium. — Carbonate of sodium is a weak agent, and does not postpone decomposition to an extent sufficient to encourage its wide adoption. So far as is known, there can be no objection to its use on the score of injury, except in so far as tiie assertion that sodium lac- tate, formed by its decomposition by the free lactic acid, acts as a mild cathartic, is worthy of credence. Salicylic Acid. — The use of salicylic acid in milk is not extensive. It is a fairly efficient preservative even when used in very small amounts. Hydrogen Peroxide. — Hydrogen peroxide is the least objectionable, and, on the score of deleterious action upon the system, the only unob- jectionable chemical preservative used in milk. According to H. Chick,^ who used a 3 per cent, solution, 0.2 per cent, of the agent will produce complete sterilization of milk, and 0.1 per cent, will keep it sweet for a week or more, regardless of whether, when added, the milk is freshly drawn or has stood for some time. The only objection noted was a disagreeable stinging taste, which can be perceived when the agent is present in far smaller amounts — even as small as 0.01 per cent. Rosara* found that 0.2 per cent, would not make milk sterile, but that with 0.1 per cent, and heating to 176° F. for 30 to 45 min- utes milk may be kept 3 or 4 days at almost incubator temper- ature. He called attention to the fact, however, that commercial hydrogen peroxide is likely to contain compounds of barium and arsenic. Jablin-Gonnet ^ suggests the use of the "12-volume" solu- tion after neutralization with calcium carbonate, and asserts that 1 cc. will preserve a liter of milk for 2 days, 2 cc. for 4 days, and 6 cc. for 6 days, even if the temperature of the milk is allowed to be as high as 86° F., and that the taste is unimpaired, Renard** found that while the agent does not sterilize the milk, it postpones sour- ing considerably. With 1, 2, and 3 cc. of the 12-volume solution the souring point was postponed respectively 24, 26, and 32 hours at 68° F., the control souring in 13 hours. Nicolle and Ducloux ^ kept milk containing 1 to 2 per cent, of hydrogen peroxide at temperatures of 60°, 72°, and 93° F., and found that the number of bacteria dimin- ished during the first 10 hours and then gradually increased. No trace 1 Centmlbktt fiir Bakteriologie, etc., I. Abt. Orig., XLI., 1906, Nos. 2, 3, and 4. 2 Zeitschrift fiir Hygiene, XLVIIL, p. 239. 3 Centralblatt fiir Bakteriologie, etc., II. Abt., 1901, p. 706. * Ibid., p. 739. ^ Zeitschrift fiir Untersuchung der Nahrnngs- u. Gennssmittel, 1902, p. 169. ^ Journal of the Society of Chemical Industry, XXIII., 1904, p. 74. ^ Kevue d'Hygiene et de Police Sanitaire, XXVI., 1904, p. 101. I'ni'.SI'ULVA'riON OF MILK. 121 of i\\v |)(T()xi(l(; w;is (IclcctaUlc iii'tcr scvctmI lioiir.s. With tlicir ;i!-.-cr- iioii tliid |);i(,li');^(wii(! orj^uiiisiriH un; not ulVcr.lcd, n:iiitii;i im ' iloc- not iljj^rco. IInd(l(i " method of j)resei-vin!i; milk eonsiht- in ;i j»er cent, solution of hydrotj;en peroxide to llie fic-ii milk in llic jiroportion of about 12 to 15 ee. to eacih liter, and then iieatin^ to 120' J'\ for three or four hours, when more tlum 5)1) per cent, of the bacteria will have IxHMi destroyed, without (^Imntj^inti' the appe:iranee or properties (»f the milk in ai\y way. Experiments made by different observers have yielded widely different results, due, accordinj^ to M. J^ukin,'' to differ- ences in the quality of the commercial jireparations of hydrogen jxr- oxide and to the fact that the amount necessary to success is influenced by the age and bacterial content of the milk. Hewlett'' tested the efficiency of the process em])loyineroxide is decomposed and no trace of it can be detected. In ordinary milk the reduction in the number of bacteria amounts to more than 99.9 per cent. Experiments with milk from tuberculous udders have given conflict- ing evidence as to the value of this process. Thus, Bergmann and Hullmann injected 1 cubic centimeter of such milk, after routine treat- ment, into a guinea-i)ig, which, after seven weeks, showed a fairly extensive tubercular infection. A sample from an udder more exten- sively diseased was treated with a larger amount of the peroxide and warmed in the usual way and injected into guinea-pigs, which in 4 to 5 weeks died of general tuberculosis. On the other hand, Svensson has obtained positive results with similar material. An improvement upon the Budde jn-oduct is known as the '' Perhy- drase Milk " of Drs. Much and Ronier,* who recommend placing the ' Miincboner medizinipche Wochenschrift, 1905, No. 23. ^ Contralblatt fiir Bakteriolosrie, etc., II. Abt.. 1904, p. 716. 3 Centralblalt fiir Eakteiiolosrie, etc., II. Abt., XV.. pp. '20, 165. * Lancet, January '27. VMM\ p. 209. 5 Beiti-iige znr Ivlinik der Tuberculose, V., 1906, No. 3, p. 349. 122 FOODS. hvdrogen peroxide solution iu the milk-pail, ^vhich should be sterile, aud milking directly into it, ut^ing- 1 part of the peroxide (about 30 ce. of the commercial 3 per cent, preparation) to the liter. After a period of 6 to 8 hours, the milk is warmed to 126° F. for an hour, and then a ferment derived from beef-blood is added, in the proportion of 0.5 or 1.0 gram to the liter. After 2 hours' contact, with frequent shaking, the excess of hydrogen peroxide is destroyed, and the milk is ready for use. It is normal in taste and is free from bacteria. Even when abundantly seeded with tubercle bacilli in the beginning, it fails to infect guinea-pigs and mice on inoculation. The ferment, called by Senter " hsemase," is a yellowish fluid, containing 0.1 or 0.2 per cent, of albumin. In its place defibriuated beef-blood, watery extract of malt^ or yeast may be used. Unless the excess of hydrogen peroxide is decomposed by the cata- lytic agent, the milk has a bitter and otherwise disagreeable taste. The same authors ^ noted that milk that has been sterilized by hydro- gen peroxide undergoes changes in color, odor, and taste on exposure to the light. Investigation showed that these changes were produced by the combined action of light and oxygen, which affect mainly the fat, and that the bottles containing the milk ought to be kept in the dark or else wrapped iu red or green paper, since red and green rays are without influence, while the ultra-violet, blue, and yellow rays bring about the changes. The assertion that no changes are produced in the constituents of milk treated by this method is denied by Professor C O. Jensen, who insists that anything which affects the protoplasm of the contained bacteria so as to cause their destruction will probably not fail to pro- duce changes in the proteid constituents of the milk ; and, as a fact, coagulation by rennet is retarded, and the coagulum is of a different character than that of untreated milk. Chromates. — The chromates are not extensively employed, but have been found present in preservative powders used in France. Deniges ^ found the normal chromate of potassium in two of these preparations, and the dichromate aud chromate together in a third. The latter was recommended in the proportion of 2 grains to 50 liters of milk. Ac- cording to Froidevaux,^ such an amount of potassium dichromate is insufficient to retard coagulation and imparts an abnormal intense yellow color to the milk. The further discussion of the subject of milk preservatives may be looked for below, under the general subject of Food Preserva- tives. Adulteration of Milk. This most important article of food is more subject to adulteration than any other, since it lends itself so readily to fraudulent manipula- 1 Berliner klinische Wochenschrift, XLIII., 1906, Nos. 30 and 31, pp. 1004 and 1041. ^ Revue International des Falsifications, IX., p. 36. 3 Journal de Pharmacie et de Chemie, 1896, p. 155. ADlJI/rEnATION OF MfLh'. 123 tioii. Tli(^ ])rlii<;l|>;il .'tdiilfcnitioDs :irc llic ;i(|(lition of w.iU-r, tlif; ahsfrac- tioii of cni.'im, .'ukI the ndinixtiin' of Hkiiiinicd milk to wliolo milk. Tin; former (iimiiiiH,li(!K tlu; imtrilivc v.'iliic, ;i(i(l, il" (Ik; waUir used is from an unclean .soure(!, incii-eascs the possibility of" disseminatinf^ dinease ; the latter robs the milk of one; of its most valuable constituents. The d(;te(!tion of these adnllcraf ions by analysis is not always j)os>ibIc, sinr>e u rich milk may be slit!;li(ly wati^rcd or only jKirtially skimmed and still show average (jiiality. A^ain, even thou^di the wateriuf^ \h'. fairly considerable, it cannot always b(! proved that tlu; milk was not of low ^rade from natural (!aus(«, since some cows give milk which, on analysis, is far below av('ratz;e o;ood milk. l^"'urther, a milk rontaininjr v<'ry little fat may be; naturally poor in that (constituent or may Ik; tlu; first j>art of a milking. In consequence of the didicnity of proving the addition of water or abstra<;ti()n of cream, and be(;ause of the enormous importance of secur- ing a, |)ublic su|)ply of at least average good (piality, most States have fixed legal standards, to which milk intended for sale must conform. The standard for total solids is commonly 13, 12.5, or 12 percent.; and for fat, 3, 3.5, 3.7, and 4 per cent. By the ado])tion of a legal standard, all milk of low grade, whether so l)y reason of fraudulent practi(;es or be use of ]X)or l'ov(\ or individual peculiarity of the cow, must be trented alike. By prohibiting the sale of all milk not of a certain grade, it becomes unnecessary to prove fraud or criminal knowl- edge, the allegation of inferior quality being sustained by the results of tlie analysis. Other forms of adulteration include the addition of coloring matters for the purpose of concealing watering or skimming, t)r to give a creamy tint to a very white milk, and the addition of preservatives, and, occa- sionally, of other foreign substances. The coloring matters commonly used are, annatto, caramel, and combinations of aniline dyes. Their detection is by no means difficult. It is a common belief, even among people of more than average intelligence, that milk as found in the market is very largely a mixture of chalk and water. Upon what this absurd tradition is based, it is difficult to surmise, since even though a person were led to practise such a miserable fraud, he would discover that chalk and water will need constant stirring to maintain even the outward semblance of milk, and that a few minutes' standing is sufficient for complete separation into a deposit of chalk and a fairly clear supernatant liquid. A less common, but equally absurd, notion that calves' brains are a conmion adulterant of milk, arose about half a century ago from the report of a microscopi- cal examination of a milk sediment in which certain particles were detected which bore a resemblance to nerve tissue. Calves' brains do not lend themselves readily to the making of emulsions, the supply is limited, and they find a fairly good market in their true character. Cane sugar is said to have been found at rare intervals, and gelatin is used occasionally as a thickening for cream. Starch is believed by many to be a common adulterant, but it is used verv rarelv. In the 124 Foods. course of many years' supervision of a large public milk supply, during wiiich several hundred thousand samples of milk were examined for adulterants of all sorts, but one instance of the use of starch fell under the author s notice. This was due to a shortage in the normal sup})ly, which led a dealer to dispense a mixture of water and condensed milk, which latter, component had been thickened with starch. CREAM. United States Standard. — Standard cream is cream containing not less than 18 per cent, of fat. Cream, as already stated, may be defined as milk containing a large excess of fit, and correspondingly lacking in water. The degree of richness is dependent upon the method employed in its separation from the original volume of milk. That obtained by the common method of skimming contains ordinarily about 16 to 24 per cent, of fat, while that separated by the centrifugal machine contains from 20 to upward of 50 per cent., according as the machine is regulated for " light " or " heavy " cream. The latter is so thick as to give rise to a common notion that corn starch is used as an adulterant. This substance, how- ever, is used rarely if ever in this way. Gelatin is employed as an adulterant to a limited extent. A preparation largely advertised to the trade at one time as a " cream thickener " was analyzed by the author, and found to be a mixture of gelatin, borax, and boric acid. More recently sucrate of lime, sometimes termed " viscogen," has been added to cream in order to increase its thickness. Lythgoe ^ states that 60 out of 1 70 samples of cream examined by him showed the presence of calcium sucrate. Furthermore, a machine has been put upon the market which pro- duces an emulsion of fat globules of such exceeding fineness as to give an impression of thickness to cream 100 per cent, above that actually present. The common adulterants of cream are preservatives and color- ing agents. The former are used mostly during the hot months ; the latter during tlie winter, when, on account of the difference in feed, the cream has not the characteristic yellow tint so highly prized. CONDENSED MILK. United States Standard. — Standard condensed milk and standard sweetened condensed milk are condensed milk and sweetened condensed milk respectively, containing not less than 28 per cent, of milk solids, of wiiich not less than 27.5 per cent, is milk fat. Condensed milk is ])repared by evaporating milk to about a third or a fourth of its volume in vacimm pans. It is sold in bulk for immedi- ate use, and in hermetically sealed tin cans for use as occasion demands. Most of that sold in tins is made from skimmed milk, and is, therefore, very deficient in fat ; and much of it contains a large proportion of cane sugar, which is added to increase its keeping qualities. Condensed ^ Annual Report of the Mass. State Board ot Health, 1908, p. 595. MILK AS A FACTOIl IN Till': SrUKM) Oh' hISHASE. 125 milk i.s, in in:iiiy njspccLs ;iihI iiikIci- c rt;iin cciHlil i'ni , ;i v:ilii:ililc I'lO'l pniparation, \n\l iLH use in inliml (rcdiii!.' wlicn oiIki- milk i- ol»l;iiniil*l(j is not !i wi.s(! one, Hin(H! it is (Icriciciil in one of llic IIlo^t. iiiii«irt:i iil *•!'•- nx^nts, unci (iontains anollicr wliidi is not a normal f^onsf it ii'iit. This point was l)ron^lil. ont, vle, but a specific micro-organism to which they have triven the name Bacillus lacfiinorbi. Trembles and milk sickness were formerly of common occurrence in Ohio, Indiana, Illinois, Kentucky, and Tennessee, and occasionally in North Carolina, but have become very rare of late years. The condition caused in man is very grave, the cerebral nervous system being jtrofoundly involved. The symp- toms include great depression and muscular weakness, great thirst, labored respiration, constant retching, paralysis of the intestines, and subnormal temperature. Before death, which is the rule, the entire body becomes paralyzed. The leaves of the common artichoke are ' American Journal of Public Hygiene, May, 1910. ^ Journal of the American Medical Association, May 23, 1908, p. 1665. 126 FOODS. siiici ^ to impart to milk certain properties which cause abdominal pain, vomitiiiir, and diarrh(ea, and Dechorf - has reported an outbreak of acute enteritis amoni:; children that had received sterilized milk from cows fed on beet leaves and red cabbage. A similar outbreak was observed after the use of milk of cows fed on fermented beet siluge. Under certain conditions normal milk may undergo peculiar forms of decomposition productive of intensely violent poisonous substances. Fortunately these changes are uncommon, but when they do occur the milk betrays to the consumer no sign of its condition. The eUects produced upon the consumer are various and are well illustrated by the following cases : Case I.— Reported by Dr. W. K. Newton and Mr. S. A¥allace.» On August 7, 1886, 24 guests of one hotel at Long Branch, and 19 of another hotel at the same place, were taken sick soon after suj)per Avith the same train of symptoms, which were nausea, vomiting, cramps, and collapse, diyness of the throat, and burning sensation in the oesoph- agus ; in many cases there was absence of diarrhoea, and in several there was active diarrhoea without vomiting. Many had violent vom- iting followed by collapse. As a rule, the nausea and vomiting were persistent and obstinate, and accompanied by a tendency to exhaustion and collapse. A week later, 30 guests of still another hotel were seized in precisely the same manner. The onset occurred in from one to four hours after eating, but in one instance the symptoms appeared almost immediately after drinking about a quart of milk. Investigation showed that the trouble was due wholly to milk, for only the milk-drinkers were seized, and those who had had no other food were the worst sufferers. The three hotels were serN'ed by one dealer, who made two deliveries daily. The milk of the second delivery was the cause of the mischief in each outbreak. It was drawn at noon, and, without being cooled at all, was carted eight miles in the heat of the day. The cows were healthy and well fed. In a portion of the milk that caused the third group of cases, the presence of tyrotoxicon Avas demonstrated. Case II. — This was a most extraordinary outbreak, limited to a family consisting of father, mother, son, and daughter, of whom all but the first mentioned died. The family physician called Professor V. C. Vaughan in consultation after the fourth member of the family was seized, and from his report of the case the following facts are taken. The first one seized was the father, a man of fifty years. When first seen, he was vomiting severely, his face was flushed, and his tem- perature was subnormal (96° F.). There was marked throbbing of the abdominal aorta, the tongue was heavily coated, and the breathing was very labored. The pupils were dilated, and much of the body was cov- ered with a rash. The vomiting continued some hours, the vomitus being colored with bile. The bowels had not moved, but under the influence 1 Milchzeitung, 1891, p. 40. ^ Paris letter, Lancet, February 8, 1908. 3 Medical News, September 25^ 1886, p. 343, MILK AS A FACTO n IN 'nih' SI'llhlAI) OF hISEASK. 127 ol" it cMilKiiiic, ;i sl\\iiij^ (l;iy. licU-.liiiijr iitid voinitiiif>' (!(»iil iiiiicil (liiilnu lli;it " l'\ All c<)in|»lained o(" a hnniin^' con- striction in tlu^ throat and didicnlt swallowin^r, and called f'reiinently for i(;c. '^J\v<) days latci", tlie mother and son died ; the daiiffhter ^rrcw worse, became nnconscions, remained so three days, and then (lied. Post-niorleni examination in the case of the daughter rev«iled no (characteristic lesions to account for death. The outbrciik was most carefully and thoroujihly in\('sti<;ated from every standj)oiut, and the conclusion reached was that tyrotoxi(!on was the cause. Tlu; milk had beeu kept iu a buttery which was in a most unsanitary condition. During; three years, the family had sull'ered frequent attacks of like character, l)ut they were much less severe. Fresh milk, j)laced in the buttery over niyht, and then examined ibr tyrotoxicou, jrave unmis- takable chemical and physiological e\idence of tliat jioison. Fresh milk inoculated with dirt from the buttery floor also developed it, a.s did also other portions treated with vomitus, stomach contents, and aqueous extract of tlie intestines, while a fifth specimen untreated remained free from it. All the evidence in this case })ointed to the more or less constant ])rescnce of poison in the milk, and the wide variation in the time of seizure in the final outbreak indicates that all were not affected by the same day's supply. Milk from Diseased Cows. — The milk of cows suffering from the prominent cattle plagues is more or less altered in composition, and there appears to be evideuce that sometimes it may be actually dangerous. Rinderpest. — In rinderpest the proteids are much increased — iu fact, more than doubled ; the mineral constituents are considerably increased, and the fat and sugar are diminished. Foot and Mouth Disease. — In foot and mouth disease the total solids are increased considerably, or diminished at different stages, and the milk \vill sometimes coagulate on boiling by reason of the excessive amount of coagulable proteids. There is reiison to believe that this disease may be comnumicated to other animals through the milk, and there is evidence that the use of the milk by man will produce local lesions in the mouth and throat. Thus, Notter and Firth^ mention an e})idemic of sore throat at Dover in 1884, in which there were 205 cases of vesicular eruption in the throat or on the lips, enlarged tonsils, and iu most cases enlarged glands of the neck, all occurring within a week iu persons supplied by a single dairy where the disease existed. ^ The Theory aud Practice of Hygiene, London, 1896, p. 305. 128 FOODS. During the epizootic which occurred iu New England in li)02, there were reported a number of oa.scs of sore mouth antl throat with aphthte and more or less general disturbance. It is said that iu mild cases of this disease the milk is unchanged, but that in severe cases it may be very abnormal in appearance and composition and may cause very severe and even fatal sickness in man. Anthrax. — In anthrax the milk has an abnormal apj)earance and decomposes rapidly. The specific organism has been isolated in active condition by Boschetti ^ from milk as late as 14 days after it had been drawn. Actinomycosis. — In actinomycosis, particularly if the udder is in- volved, the milk should be avoided, although there appears to be little direct evidence bearing upon transmission of the disease to man by this means. It is certain, however, that the disease does occur some- times in man, and though in the matter of transmission of disease from animals to man nothing siiould be taken for granted, it is commendable in such cases of lack of positive knowledge to err on the side of safety, and to avoid and prohibit the use of such milk, even though it be true that the actinomyces have not as yet been found in milk. Rabies. — In rabies it has been proved that the virus may be secreted in the milk, and Jensen - says that although feeding experiments have yielded negative results, the possibility that infection may occur through a slight lesion of the mouth or pharynx should cause the milk of cows bitten by rabid dogs to be regarded as most dangerous. Specific Enteritis. — In specific enteritis due to the hog-cholera group of bacteria, the milk, which, perhaps, is infected through fecal con- tamination, if not before it leaves the cow, may be a cause of sickness. Gaffky ^ has reported this case : Three persons connected with the Institute of Hygiene at Giessen were seized, after drinking milk from a cow suffering from such a disease, with nausea, vomiting, diarrhoea, and mental confusion. One recovered in a few days, the others in about four weeks. The milk was drunk in the raw state. Garget, Mastitis, Maramitis. — In this commonest of bovine diseases, in which a part of or the whole udder may be inflamed, the milk is often so changed in character as to be obviously unfit for use, but ordi- narily is of normal appearance on casual examinntion. Even when the udder is only slightly involved, the milk frequently contains vast numbers of streptococci. B. coll is almost always present, and Staph, pyogenes aureus and albus are very commonly found in large numbers. Such milk is believed by many to be a common cause of epidemic diar- rhoea, and in a number of instances the connection appears to have been conclusively proved ; but the most striking effects of its use are the extensive outbreaks of septic sore throat, which sometimes have passed for scarlet fever, as, for examj^le, an outbreak of more than 200 cases in Lincoln, England. These outbreaks are often extremely se- 1 Giomale di Medicina Veterinaria, 1891. 2 Essentials of Milk Hygiene. Trans, by Pearson, 1907, p. 91. 3 Deutsche medizinische Wochenschrift, 1892, No. 14. MIIJ\' AS A FAdTOn /;V Till': SI'liF.AI) animals with the milk of 50 reacting cows, not one of which showed clinical or post-mortem evidence of udder tuberculosis, and not a single one of the animals acquired the disease. It is asserted commonly that the use of milk from tuberculous cows is a positive danger to public health, and attention is directed to the persistently high rate of mortality from tuberculosis in all its forms among very young children, and to improvement in the death-rates from other causes. It is asserted that this condition can be explained in only one way : that is, that a very large proportion of market milk is derived from tuberculous cows, and thus bottle-fed children, if at all susceptible, become infected. As to the probable j)ro]iortion of infected market milk, owing to the wide diiferences in results obtained by various investigators, no definite statement can be given. Rabinowitsch, for example, found it to be 28 per cent, ; Massone ^ by inoculation experiments placed it at 9 ; Ott,* at 11.6. Sladen " found that more than half of the samples tiiken from the supply of the colleges at Cambridge, England, conveyed tubercu- losis to guinea-pigs on inoculation. Del^jnne found the l)acilli in 17.6 per cent, of samples gathered in IManchester, and Robertson, in 14 per cent, of samples collected in Birmingham. Houston has estimated that about 20 per cent, of the cows in the United Kingdom are tuber- culous, and that 2 per cent, have tuberculosis of the udder. Ostertag believes that the udder is involved in about 4 per cent, of tuberculous cows. Eastes^ found the bacillus in but 11 of 186 samples of milk which he examined. According to Newman,^^ in Liverpool about 2 per cent, of the town-produced and 9 per cent, of the country milk has 1 Hygienic Laboratory Bulletin, No. 41, p. 493. 2 Zeitschrift fiir Hygiene und Tnfectionskitinkheiten, XXXVIII., 1901, p. 415. 3 Zeitschrift fiir Tiermedizin, YI., 1902, p. 241. * Annali d'lgiene Sperimentale, 1897, p. 939. 5 Z.eitschrift'^fiir Milch- und Fleischhygiene, 1898, No. 8. 6 The Lancet, January 14, 1899. '' British Medical Journal, November 11, 1899. 8 Public Health, February, 1904. 132 FOODS. been foiiiKl to be tuberculous ; in Hackney, on one occasion, 22 ])er cent.; in Woolwich, in 1902, 10 per cent.; in Caniberwell, in 1902, 11 per cent. ; in Croydon, in 1901, G per cent. ; in London, as a whole, 7 per cent. Anderson^ found that 15 out of 223 samples of market milk, that is to say, 6.72 per cent., caused tuberculosis in inoculated animals. The milk, furthermore, of 11 out of 102 dairies contained tubercle bacilli. Moreover, the milk from one out of nine charitable institu- tions caused tuberculosis in both guinea-pio;s into which it was inocu- lated. Hesse -found virulent tubercle bacilli in 17 among 107 specimens, that is, in 16 per cent, of the milk retailed from cans in New York City. Tonney^ found that 8.9 per cent, of 112 samples showed tubercu- losis. Of 95 raw samples, 10.5 per cent, showed tuberculosis. Of 17 pasteurized samples, per cent, showed tuberculosis. Doubtless the differences are due to variations in local conditions, to differences in technic, and to accidents always attending haphazard securing of any article of food in open market. Taking the mean of the figures given, and accepting that as a fair approximation of the extent to which public supplies are infected, it must be agreed that, if infection through milk is possible, the amount of disease so caused is quite small in proportion to the number of the population who are exposed daily to the danger. There are but fcAV reported cases in which the influence of other possible conditions can be excluded so thoroughly as to leave no reasonable doubt of the causal relation of milk. Single instances are necessarily of less value than groups of cases, and the latter are much less conmion than generally is supposed. From the number available the following are selected as illustrations : Brouardel* records the death of 7 children with no hereditary taint, inmates of a convent, from tuberculosis supposedly induced by the use of milk from a cow with tuberculosis of the udder. Another case reported by him, and quoted by Freudenreich,* is one in which 5 of 14 girls in a boarding-school became infected and died. The milk which they had used daily came from a tuberculous coav. Demme" reported as the only instance in his experience in which all other causes could satisfactorily be excluded, a group of 4 infants of healthy parentage fed upon uncooked milk of tuberculous cows. They all died of tuberculosis of the intestine, and the diagnosis was confirmed by autopsy. Later, he reported^ still another death from the same cause at four months. In this case also there was absolutely no family 1 Hygienic Laboratoiy Bulletin, No. 41, p. 191. ^ .Jour. Am. Med. Assoc, Mar. 27, 1909. 3 Ibid., Oct. 8, 1910. ■1 Annales d' Hygiene publique, XXIV., p. 65. 5 Les Microbes et leur des Kole dans la Laiterie, Paris, 1894, p. 45. ^ .Jahresbericht iiber die Tliiitigkeit des Jenner'sclien Kinderspitals • in Bern, 1882, p. 48. 7 Ibid., 1886, p. 20. MILK AS A FAdTOn IN Till': sriil'.M) OF hISEASIC. 103 liiKtory ol" tiilxsrculosis. Al'lcr llic '•(.ii(Irrii;iti<)ii of llic (Jiagnohih by autopsy, the cow wan Hluii^litcrod iiixl round to Lc inlx iciiIoiih. Mull(!t' foiiii;ed without (rainin*^ entrance to th(; tissues. Graiitinti; that iiiueii of the public milk supply is derived from tuber- culous cows, and that it is consumed very lar<:;ely in unsterilized r-oudi- tiou by very younji; children, one would naturally expect, if the bovine bacillus is markedly infective to man, to find a very high death-rate from alxlominal tuberculosis among the very young. It is asserted that this is the case, and elaborate arguments in favor of the statement that tuberculous milk is responsible lor a great part of the constantly high infantile death-rate have been based on figures given by the late Sir R. Thorne-Th(M-ne, in his Harben lectures, in November, 18!)8, showing that, whereas in England and Wales the returns for 1891—1895, comjiared with those for 1851—1860, indicate a reduction in mortality from phthisis at all ages of 45.4 per cent., and from all forms of tuberculosis of 39.1 per cent., the decrease in tabes meseuterica was for all ages only 8.5, and for children under five only 3 per cent. ; and that, moreover, for children under one year there was not only no reduction, but an actual increase of 27.7 per cent. Such figures, emanating from so high an authority, would seem to admit of but one explanation, namely, that infected milk is a danger hardly to be overrated. But these figures are directly opposed to clinical experience elsewhere and, as Avill appear, are incorrect. Dr. D. Bovaird^ points out that it is only in England that reports indicate any considerable number of cases of primaiy intes- tinal tuberculosis, and asserts that it is very rare in and about Xew York City, and that the evidence connecting tuberculosis in children with infected milk is very meagre. Koch has called attention to the great infrequencv of primary tuberculosis of the intestine among children in institutions in Berlin ; and Biedert,^ too, asserts that the amount of tubercular infection through the alimentary canal is veiy small. Adami * ^ Quoted in L'Eobo medical dii Noixi, April 2, 1903. - Archives of Pediatrics, December, 1901. 3 Berliner klinische Wochenschrilt, November 25, 1901. * Philadelphia Medical Journal, February 22, 1902. 134 FOODS. is of the opinion that tuberculosis of young children, and especially peri- toneal and intestinal tuberculosis, is remarkably rare in the great cities of North America ; but Jacobi,* while admitting that primary tubercu- lar ulcerations of the intestine and primary tuberculosis of the mesen- teric glands are rare, holds that peritoneal tuberculosis is very common. Adami cites the mortality returns for INIontreal for the year ended June, 1900, showing that of 935 deaths from tuberculosis, but 4 were of children under fourteen, and 3 of these were from abdominal tuber- culosis in children under five years. Crookshank^ dissents from the opinion that abdominal tuberculosis of children is connected with in- fected milk, but believes that not sufficient consideration is given to the possibility of infection from lunnan sources. The fallacy of Thorne-Thorne's figures has been pointed out by Carr, Guthrie, Donkin, and others, and all arguments based thereon must fall to the ground. In December, 1898, Carr^ showed that the vast ma- jority of cases returned as tabes mesenterjca Avere probably of maras- mus, due to gastro-intestinal catarrh. Guthrie* coucluded from the results of 77 autopsies performed by him on tuberculous children that the disease begins far more commonly in the chest than in the abdomen, and that tabes mesenterica as a cause of death in young children is practically unknown or extremely rare. Donkin, who contends that the original significance of the term "tabes mesenterica" no longer holds, says : ^ " We all know that all kinds of intestinal and other dis- orders are constantly styled ' tabes mesenterica ^ by those who fail to cure them." It has been pointed out that whereas in England about 10 per cent, of all tuberculosis and about 30 per cent, of tuberculosis of children is classed as tabes mesenterica, the respective figures for Berlin in 1898 were 1.8 and 2.8, for Paris, in 1897,-1.33 and 1.65, and for New York, in 1899, 0.47 and 2.86. Stowell,^ who has had an unusual opportunity to study the influence of milk of tuberculous cows at the New York City Children's Hos- pitals on Randall's Island, relates that during two years the milk supply consisted of market milk which was pasteurized at 155° to 165° F. and milk produced on the island. The latter was reserved for use in the raw state by the very young and the acutely sick. In October, 1907, the herd of 28 cows and 2 bulls was tested with tuber- culin, and all but 3 reacted. All the animals were slaughtered and examined. The non-reacting animals proved to be free from tubercu- losis, but all the others were diseased. Of the entire number, but 1 had udder tuberculosis. Stowell's experience led him to conclude that since, during the use of this milk, there was no evidence of any more development of tuberculosis among those who received it than among those who had pasteurized milk, the danger of tubercular infection from milk must be very slight. ' New York Medical .Journal, .January 25, 1902. 2 The Lancet, November 2, 1901. 3 Ibid., 1898, II., p. 1662. * Ibid., 1899, 1., p. 286. ■' British Medical Journal, October 14, 1899, p. 1046. « Medical Record, June 20, 1908, p. 1023. MILK AS A FAdTOIl IN Till': .SJ'R/'JA/} OF DISKASK. 13.0 Notwithst'indiiif^ tlic |):iiic,ily of cMHfH wliicli oH'cr ntron^ cvidciu^; <»f" a cauKal relation l)('tw<'(!M inrcctcd milk mikI tlu- occurrence; of tiibcrcu- lo.sis, ;ni(l in spile of flu; now rccuij^tii/cd dilll ivnccs hctwccn \\h- hovliu; and linnian hiic.illi, IIm; possihilily of" dimmer in individual c;i.s(!.s cannot li^Iiily l)c l)nislic(l aside. yVccordinir to 'I'lurohald Srnilli/ it Ih fpiitc possiliie that HouKitliin^ intcrfer(^s vvitli the al)Hor|»fion of bovine Inicilli, while allowing tli(! liunian bacilli to pass ; and while racial di(!"er(!n(MJ8 probably pn^vent the absorption of bovine ba(;illi under ordinary circum- stances, and a few bacilli are harmless, there is danj^cr if the di^e.-tive tract is flooded with bacilli from tubentulouH luhhtrs. Ostertaf^ advo- cates tlio cullinji; out of all cows showing clinical evidence of tubercu- losis (beyond rea(;tinp^), and especially of all with lesions within the udder. Tjcblaiic^ is of tlu; opinion (hat the milk of tuberculous cows is danf>;erous, not on account of the bacilli, but on account of the t^^xins that it contains, for it has been ])roved to liave toxic properties. Michellaz/i has shown that such milk injected into tuberculous ani- mals causes a reaction, and that the milk of a tuberculous mother will in time prove toxic to her child. However great or small may be the danger from the use of tubercu- lous milk, it may be entirely avoided by using the milk of goats in- stead of that of cows. Wright^ has called attention to the ifact that the goat is a clean animal as compared with the cow, that its feces are solid and rolled in balls and hence not likely to become attached to the flanks and udder, and that it is practically immune to tuberculosis, Nocard having failed to find a single case of tubercular lesions among 130,000 slaughtered goats and kids. To the common objection that goats' milk is offensive in odor. Burr* answers that, drawn in a clean stable, the air of which is not made offensive by the presence of the male animal, goats' milk is as free from distinctive odor as cows' milk. Goats' milk appears to be quite as digestible as cows' milk, if not more so, especially if it is taken, as in some European countries, warm from the animals. Wood ^ advises very strongly the use of goats' milk for bottle-fed infants, stating that not one of a number under his care so fed during the whole summer had any diarrhoea whatever. Curiously enough, however, in its relation to another disease goats' milk has been proved to be very dangerous. For a number of years epidemics of an irregular fever on the Island of jSIalta remained unex- plained, although the specific organism of the disease (the Micrococcus mclitcnsis) was discovered by Bruce in 1887. Although the disease may be spread by other means, it has been found that the ingestion of the milk of infected goats constitutes the main channel of transmission. As soon as this fact became known and the milk excluded as an article of diet, the occurrence of Malta fever was to a large extent eliminated. 1 Medical News, February 22, 1902. •' Lyon Medical, April 14, 1901, p. 561. 3 The Lancet, November 3, 1906. * Milchzeitung, 1907, Nos. 19-21. ^ Intercolonial Medical Journal of Australasia, Mar, 1907. 136 FOODS. Milk Contaminated from Without with Organisms Related to Human Diseases. — Milk may become contaminated with infective matter in various ways. It may receive it from the liands, person, and clothing- of the milkers and others by whom it is handled, whether they are themselves sick or convalescent or acting- in the capacity of nurse or attendant for others ; it may acquire it from unclean vessels rinsed in polluted water, or from water with which it has fraudulently been mixed. The first to demonstrate that human diseases may be spread by cows* milk was Dr. Michael Taylor, who was led to the idea by the occur- rence of 13 cases of typhoid fever in 7 of 14 families supplied with milk from the same farm, the prior introduction of the disease into the farmer's flimily by an infected domestic, and seizure of two of his chil- dren. This outbreak was reported by him,^ but the publication excited no special interest, and, indeed, it fell to him to report also the second milk-borne outbreak discovered 10 years later, this one of 15 cases of scarlet fever in 6 of 14 families supplied by a farmer whose wife milked the 4 cows and nursed at the same time a child fatally ill with the dis- ease. A few years later the matter of milk-borne infection began to receive attention, and now the reports of such outbreaks number many hundreds. On account of the danger of specific contamination of milk, no per- son sick with or convalescent from infectious disease, and no person having to do with the care of the sick, or with the disposal of their excreta, or with the washing of their linen, should be allowed to handle milk intended for the use of others. Public authorities are rapidly becoming awakened to the importance of restrictive measures in this regard, and in many communities it has been made a criminal offence to fail to give notice of the presence of cases of infectious disease at the place of production of milk or among those engaged in its distribu- tion and sale. According to Anderson,''' an outbreak of typhoid fever, due to con- tamination of a milk supply, is characterized by the sudden outbreak of an unusual number of cases followed by a rapid decline ; by the ap- pearance of an unusual number of cases among customers of a certain dairy ; by the unusual incidence of cases among users of milk ; by an excess of cases among the well-to-do as compared with the poor ; and by the finding of the typhoid bacillus in the suspected milk. It is, to be sure, very rare that the typhoid bacillus can be isolated from milk, but it should be attempted, and, if successful, is conclusive. Diphtheria. — A large number of epidemics have been reported in which a positive connection with the milk supply appears to have been fairly well made out ; but so far as is known, there is no connection between any disease of the cow and that which we know as diphtheria, although a number of outbreaks of diphtheria have been reported as traced to garget. The specific organism of diphtheria may be intro- 1 Edinburgh Medical .Journal, 1858, p. 993. ^ Am. Jour. Pub. Hygiene, May, 1909. MILK AS A FACTOn. IN 'I'lll': smiCAh OF hlSFASE. I.')? (lii(!(!(l into Miilk (Voni llic (ll:-(li;iru's oC pcisoiis ciiiidoycii in llic li;in(|- lin<»- ;in(l (list.riWiition of milk licroic tJicy lijivc; rccovr^nid llioroiij^lily (Voni iJic (lis('JiS(^ J)r. J. W. 11. iMn; ' fonnd flic hMcillns of (li|)li(licriu in siunpios ol" inilk .supplied l(» ;i l:irtr<' scliool wlicrc a nuniIxT of cawH of the discilHC had occMrrcd. Il lias hem roiind i< pciti <||y in HilHjH!(;t(' di|)litlieria, c|)i(l((mics reported as sjiread by milk and compiled since 1 .S})r) by Trask,' IT) occurnid in the United States and 8 in (irciat IJritain ; cases of the di.sease occurred at the producinj^ iartn, distributint^ alii-a(;l, the pacliciihir chi-s wliosc; liornctH wen; invaded. Tlu; children alleeUMl belonged to closely allilial*'*! ^ronp.s of j)liiytn!it(!H. Furtluir investipjalion revealed the fact ihat the lirKt rsiHC was of a laxl whose, family was not a cnstonK;!' of* IIk; siisjieeted dealer, and that, inunediately heCoi'c! taking to his bed, Ik; had heen playing with a nntnl)(!r of (hose; who were muou^ tin; uc.xl to he seized. 'IhcHe in their turn had be(!n associated with others, and ko the infection had spread. Thus, wiiat niif^ht have served as a most useful example of a milk-horiK' ei)idennc of se;irlet f(!V(!r fell to the ground, ;iiid the unfor- tunate dealer was al)solve(l from r(!Si)onsil)ility, "Of the 51 scarlet fever epidcmuvs reported as spre;id by milk com- piled by Trask,' 25 occurred in the United States and 2G in Great Britain ; all eases enumerated in the outbreak were reported as living in houses su|)j)lied with the suspected milk in 27 of the ej)idemics ; a case sullcrini>; from the disease at su(!h a time as to have been the pos- sible source of infection was found at the producint:: firm, the distribut- ing dairy, or milk shop in 35 cases ; the outbreak was su])pose l<<(|) 'J cows, ;iii(l .since tliut time caw.- oC tv- plioid iov(!r liiivo occMincd niuon^ liiH milk cUHtomerH uh fbllowH : No. of CiiHOH. September, 1 !)()() 1 April, l'.K)7 2 (poHKil)ly :{) May, l'.)()7 1 June, VMH 1 Ht'|)tciiil)CT, l'.K)8 '2 (pdMsihle cji.HCH wiifi to l)i: riiHtom«;rH f)f X) March, I '.»()!) 1 AugiLst, I !)()!) ] September, J !)()'.» 2 Total II (or possibly 12 cases) These (';i.se.s of tvplioid fever liave been efjnfined 1o ;i residence por- tion of tlie town ;il)()nt ii;df a mile S(|n:ire, eentei"iii^ about X's lionse. Tlie region is in the better j)ortion of tlie town, well elevated, with good hygienic! conditions, and not (ilose to the mills or the river. The peo[)le arc seemingly of moderate means, not foreign born, and of good intelligen(;e. The honses have separate cesspools. There is no town sewer. The water supply is the same all through the town. The ice for the whole town comes from the same scMirce — the river. There is a well in the neighborhood used by a large number of people. Several of the typhoid cases did not use this well, and many other uninfected persons did get some of their drinking water there. X did not use this well. The hygienic condition of X's place is quite unsuited for the produc- tion of milk. The cesspool is not carefully sealed. The barn is filthy and fly infested. An unguarded jn'ivy drains into the cellar, Mhere the manure and a pig are ke]it. Complaints have been made by the neighbors of the smell from the place. X has kept two cows, which have yielded him about two 8i-quart cans daily. He milks the cows and strains the milk himself. Mrs. X washes the cans. The milk is peddled about the neighborhood by X soon after it is milked. It is not iced. Specimens of feces and urine from X showed no typhoid liacilli in the feces, but there was an abundant growth of motile bacilli in the urine. The bacilli corresponded in cultural and agglutination char- acters to typhoid bacilli. X was informed of his condition and forbidden to distribute any more milk. At the beginning of the year 1910, four and a half years after his typhoid fever attack, this man shows a constant typhoid bacilluria. He has no symptoms of cystitis, and feels better than he did before being sick. A year later it was found that several more cases of typhoid fever occurred in the same town, and investigation brought out the fact that 142 FOODS. this farmer X, although forbidJen to sell his milk, had been giving away to his neighbors an excess which he had, in the absence of his wife. Those individuals, however, who were unfortunate enongh to accept these gifts, promptly came down with tyjihoid fever, thus show- ing that the larmer, with his filthy habits, had been again responsible for infecting his milk supply. Another ei)idemic reported to the Massachusetts State Board of Health affected 59 persons who took breakfast at a certain hotel on Labor Day, 1909. This epidemic was traced to a waitress, who, in the prodromal stage of typhoid fever, had access to and undoubtedly did infect a can of milk. This can of milk, improperly iced and there- fore of a tem])erature favorable to the growth of the bacilli, was used at breakfast by the affected persons. "Of the 179 typhoid epidemics reported as spread by milk com- piled by Trask,^ 107 occurred in the United States, 43 in Great Britain, 23 in continental Europe, 3 in Australia, 1 in New Zealand, and 2 in Canada ; all cases enumerated in the outbreak were reported as living in houses supplied with the suspected milk in 96 of the epi- demics ; a case, suffering from the disease at such a time as to have been the possible source of infection, was found at the producing farm, distributing dairy, or milk shop in 113 cases; the outbreak was sup- posed to have been due to bottles returned from infected households and refilled and distributed without previous sterilization in 4 cases ; the diseased person or persons were mentioned as handling the milk or milk utensils in 2 ; the sick milked the cows in 6 ; the same person nursed the sick and handled the milk or milk utensils in 6 ; same person was mentioned as nursing sick and milking cows in 10 ; ice cream was given as the infective medium in 3 ; whipped cream in 1 ; typhoid dejecta were reported as thrown on the ground in such a way as to have more than probably contaminated the well water used for washing the milk utensils in 4 ; in many cases mention was made of special incidence of the disease among persons in the habit of drinking milk ; the Eberth bacillus was isolated from the milk in 1 case (Konradi) ; it was reported that measures taken upon the presumption that milk was the cause of the epidemic, and looking to the removal of this as a factor, were followed by abatement of the outbreak after due allowance for the usual period of incubation from the distribution of the last infected milk in 78 of the cases." In reporting milk epidemics, some of the points of special interest, as given by Trask,^ are the following : " 1. The number of cases of the disease existing in the involved territory during the time covered by the epidemic. " 2. The number of houses invaded by the disease. " 3. The number of invaded houses supplied in whole or in part, directly or indirectly, by the suspected milk. ^ Hygienic Laboratory Bulletin No. 41, p. 24, 2 Ibid., p. 47. Mlfjh' AS A FACTO/:. IN TIHC SI'IiHAD OF DISK ASF. M3 "1. 'V\\i.\ iiuiribcr of casoH ()c,y Khin in three (liU'crcnt oiifhrciikH iUnoner- sons concerned in both outbrejiks obtained their milk i'voxn the same dealer, whose cans, which had a sour smell, yielded on bacteriological examination a bacillus having all the characteristics of the one men- tioned. Families which were su]ipli(>d by the same de;der, but directly from the goats, showed no symptoms, and the goats themselves were free from diae;ise. Andrewes^ has described 3 much more extensive outbreaks, referred to above, due to the same organism, in one of which the offending food was found to be rice pudding made with milk. The first and second outbreaks, in which no one article of food could be incriminated, in- volved respectively 59 and 146 patients; the third involved 86. In all 3 outbreaks, the great majority of the attacks were mild, but in some of the more severe cases, the discharges contained mucus and blood. In all 3, the organism was found in the stools, and in the second, it was found in the milk given out on the previous day. lu the third, it was impossible to obtain any of the milk, but the pudding made with it yielded the organisms, in s]>ite of the heat to which the compound had been subjected during its preparation. It was found by direct experi- ment that the interior of such a pudding did not attain a temjterature above 98° C. during cooking, a temperature below that necessary for the destruction of the spores, which are among the most resistant known. 1 British Medical Journal, ^Slay 12, 1900, p. 1151. 2 The Lancet, January 7, 1899. 10 146 FOODS. Fig. 2. WATER C.G120 ^65^ Feser's lactoscope. Analysis of Milk. For ordinary purjxjses of determining- the quality of milk, the pres- ence or absence of added water, and whether it has been i-obbed of its cream, a coniplete chemical analysis is by no means always necessary, since much may be learned from Fig. 3. simple inspection by means of the lactodensimeter and the lactoscope. The lactodensimeter (Fig. 3), or lactometer, is merely a large hy- drometer with a stem graduated to show specific gravities ranging from 1.015 to 1.040. The lactoscope, invented by Professor Fcser, is an instrument designed to indicate the approximate fat content of milk. It consists of 7 glass cylinder, into the base of which a smaller cylinder of white glass, closed at the top and mounted on a metallic base, is fitted. The larger cylinder is grad- uated along the side ; the smaller one bears a number of black hori- zontal lines. The instrument is shown in Fig. 2. The principle of the instrument is based upon the fact that the opacity of milk is due mainly to the fat globules in suspension, and that, therefore, the richer a milk is in fat, the greater is its opacity, and the more it must be diluted to reduce the opacity to such an extent as to permit the passage of light. The method of use is as follows : Four cc. of the specimen are de- livered from a pipette into the cylinder through the opening in its upper end, and then water is added in small portions and thoroughly mixed by inversion of the instrument, the orifice being kept closed by the tip of the forefinger. As soon as the successive additions of water have reduced the opacity of the mixture to such an extent that the black lines on the white cylinder can be discerned so distinctly that they may be counted, the height of the liquid on the scale is noted and the per- centage of fat indicated is read. Four cc. of skimmed milk will re- quire so little water that, when the lines can be seen, the level of the mixture will be very low on the scale, while with rich milk it will be ANAl,YS/S OF MII.K. 147 eorr('S])f)H(liiiu;ly lii^li, mihI willi civ'utii the whole cyliiiilf r will !)<• fillc(!, and then if a small amonnt of water is added, the jrravity is hron^ht down to l.().'>2; that is to say, within normal limits. Thns, a milk after being doubly treated so as to reduce its nutritive value, niiiy show a normal sj)ecific gravity, and, on this t<,'st alone, bo (biassed as pure. Nor is this the only (»bjection to a system of insj)ec- tion of this most important food based upon the use of the hurtometer, since milks exceptionally rich in tat have a specific gravity below the normal, and thus may be condemned as watered. The lactoscope alone is also not to be dejicuded upon in all Cti.';e>;, since a milk whi(;h shows a normal content of fat may be oik; of con- siderable richness in that constituent and extensively watered. Thus, a specimen containing originally 4.50 per cent, of fat may be watered! very considerably, and yet show 3.75 per cent, by the lactoscope. By combining the use of both instruments, however, the fallacies of either arc exposed. A normal specific gravity shown by the one and a normal fat content revealed by the other will indicate that, even if the milk has been tampered with, it yet possesses average richness. A normal specific gravity with a low percentage of fat will indicate skim- ming and watering ; low specific gravity with normal or low fat, water- ing ; and high specific gravity with low fat, skimming. Low specific gravity with very high fat will indicate unusual richness ; thus, cream has a very low specific gravity, due to its preponderance of fat. As a test of the accuracy of this process of examination, the author^ caused to be analyzed under his supervision 1,714 specimens which appeared by those tests to be of good quality, and of this number but 8 were found to have deviated materially from the statute requirement of 13 per cent, of total solids. Determination of Specific Gravity. — In taking the specific gravity by means of the lactodensimeter, the milk is mixed thoroughly, in order to insure homogeneity, by pouring from one vessel into another ; a cylinder of suificient depth to allow the instrument to float freely is filled with the milk, and the instrument is carefully inserted, not dropped, down to the bottom, and then released. When it comes to rest, the reading of the stem at the level of the surface of the liquid is noted. It should be borne in mind that air bubbles are retained rather tenaciously by the milk, and tend to lower the density, and, therefore, 1 Thirty-first Annual Report of the Inspector of Milk, Boston, 1SS9, p. 11. 148 FOODS. Fig. 4. in mixing the milk, too violent action nuist be avoided, and a short time should be allowed for the bubbles present to rise to the suri'ace and escape. Inasmuch as the gravity varies with the temperatiu-e, and the instru- ment is graduated for 59° F., either the milk should be brought to that temperature, or a correction should be made accord- ing to the deviation above or below that point. If the milk is colder, the reading will be too high, and, if warmer, too low. It is more convenient to make a cor- rection for temperature than to heat or cool the speci- men to the normal point. The deduction of a half de- gree of gravity for each five degrees of temperature below 59°, or the addition of the same amount for each four degrees above 59°, will be found to be approximately accurate corrections. Determination of Fat. — For the accurate determina- tion of fat, several methods are in use, including the following : I. The Paper-coil Extraction Method. — This process requires strips of thick filter-paper, free from substances soluble in ether and alcohol, about 6.25 by 62.5 cm., and a Soxhlet extraction apparatus. The most approved form of the latter consists of three separate pieces which fit together by ground-glass joints (see Fig. 4). The top and bottom pieces are, respectively, an upright Liebig condenser and a flask. The middle piece, which is the part in which the extraction process occurs, consists of a . , N_>^ glass cylinder, closed at the bottom, from which a nar- v::~| rower cylinder with open end projects downward. The two cylinders are connected by a side tube which opens into the upper portion of each, and also by a siphon which opens from the side of the bottom of the large cylinder, extends upward, then turns upon itself, pierces the middle part of the wall of the lower cylinder, and terminates within and just below its lower end. When in use, the substance to be extracted is placed within the upper cylinder, upon the bottom of which is placed a wad of absorbent cotton, which prevents the entrance of solid particles to the siphon tube, or it is con- fined within a cartridge of thick filter-paper which fits loosely within the cylinder. When the cartridge is used, it is best to plug its open end with absorbent cotton, in order to pre- vent the escape of fine particles of the contained substance. The three separate parts are joined together and then mounted on a water-bath. The ether or other extracting medium is contained in the flask, the exact weight of which has been determined. The heat of the water-bath causes the ether to volatilize, and the vapor passes upward Soxhlet extrac- tion apparatus. ANAI.VSIS OF MIIJ-C. H9 tliroil^li Ui(i Hide lillx! info I lie cxI ciH^lor mikI llictx-c lo I lie coimIciixt, wIkm'c, (5(>iniiie or blown out with the assistance of a double tube such as is used in wash-bottles, the delivery tube extending- into the ether layer very nearly as far as the line of demarcation between the ether and the acid mixture. The operation is repeated with several fresh smaller portions of ether, and the whole of the ether used is collected in a weighed tlask. Then the ether is distilled off, and the Hask with its residuum of fat is heated to constant weight in an air- bath, cooled, and weighed. The process may be shortened considerably by treating the milk in a graduated tube and, after thorough shaking with ether, removing an aliquot part of the latter by means of a pipette and evaporatmg to dryness. From the weight of this residue, the amount of fat in the Avhole volume of ether can readily be determined. Since the milk taken is measured, and not weighed, a correction must be made for gravity. Example. — Amount of milk used = 10 cc. Specific gravity of specimen = 1.032. AVeight of milk used = 1.032 X 10 = 10.32 grams. Amount of fat found = 0.397 gram. Percentage of fat in the original milk = x in the equation, 10.32 : 0.397 : : 100 : x ; x = 3.84. 3. The Babcock Centrifugal Method. — In this process, equal volumes of milk and sulphuric acid are mixed in flasks of special design with narrow, graduated necks, and then whirled in a centrifugal machine for a definite length of time. On the completion of the process, the details of which are given below, the fat in a pure condition is within the graduated neck, and the percentage is read directly off. The kind of flask used is shown in Plate III. It has a capacity of about 40 cc. The graduated portion of the neck has a capacity of 2 cc. The details are as follows : 17.6 cc. of the milk are measured by means of a ])ipette and introduced into the flask. Then an equal volume of sulphuric acid, specific gravity 1.800, is added, and the two liquids are mixed thoroughly by gentle rotaiy motion. Then the flask is placed in a centrifugal machine made especially for the purpose, and whirled for five minutes, at the expiration of which time hot water is added up to the beginning of the neck. The flask is whirled again for two minutes, and more hot water is added so as to bring the fat layer well u]) into the neck. After further whirling for one minute, the depth of the fat layer is determined by reference to the scale. This process gives sufficiently accurate results for all practical pur- poses, and is in common use at experiment stations in this country. It is much used at creameries for determining the butter value of milk sent in from the surrounding country. The employment of sulphuric acid having a higher specific gravity than that given, say 1.820, is objectionable in that it frequently happens that it is impossible to obtain a clear fat layer. The fat itself may be turned a very dark color, and the sugar of the milk may be attacked to such an extent that charred portions of it will separate and accumu- late within and beneath the column of fat, and so prevent a satisfactory reading. If the acid used is weaker than 1.800, all the casein may not IM ,A'I )■. Ill 8 ■T: 6 ■ 5 4 -3 -2 I Babcoek Flask, showing Fat in Neck. yl 7V/I /. r,S7.S' (>F MILK. 151 be held In Holiitioii, iiiid portions oC it iii;iy tninj/lf with the liiL and destroy the aeciiiiicy o(" tlic tcsl. In Piute III. is shown flic \\\i liiyer in the slein mh it should he;, fr;h. The dilfenmee between this weight and that of the dish alone represents the total solids of the amount of milk taken, and, multiplied by 20, expresses the percentage of total wdids in the sample. If for any reason it is desired to use tlie total soliy W(!i}^lit. Supposing (Ik; spccriCic, frruvity to Im- I.O.'W), for ('xarnpK;, tluj 100 <; ^raiiiH, and llu; \u'ycA'i\injj;('. ol' hiif^ar will ho X ill the (!.'}. Ina.sniiich an the; uuiaiis ol" llie first (^(piiitioii nvv. conslaiits, tlu; rcrkoiiiri}.'; resolves ifsc^lf into dividing fonr times (heir |)roduet, .'>.'). .'>o, or 1. '>.'}. 1 hy the niiinher of ee. used, and dividing this result \)y the .specific gravity of the specimen. 2. Method of Polariscopy. — Tlu; delerniiiKitiuii uf lacto.sc and other sugars l)y means of the j)olaris(tope eomhines the ;i(l\ant}igc.s of accu- racy and of rajjidity. The instruments in eouiiiHMi use arc of two kinds : those of which the normal sucrose weight, that is ix) say, the amount of sucros(^ whi(Oi, dissolved in water and made u|) to 100 c<;., will show 100 degrees on the scale when observed through a 2t)0 mm. tube, is 2G.048 grams, and those in Avhich it is Kj.ll) grams. Of the former, the Vent/kc-Scheibler and the Schmidt and Ilacnsch modifica- tion, and of the latter the Laurent instrument, may be regarded as types. The Schmidt and TTaenseh triple field, half-shadow instrument possesses the advantage of doing away with the matching of colors, and hence may be used by those who are color-blind, and even with those not so afflicted gives, on the whole, the most satisfactory results. Process. — Into a flask graduated on the neck at 102.0 cc. if the in- strument used is one of which the sucrose normal weight is 20.048 grams, weigh 05.95 grams of milk, or into one graduated at 101,0 cc, if it is one of the other class, weigh 40.99 grams, add 1 cc. of solu- tion of mercuric nitrate of pharmacopa?ial strength, shake well, and dilute with water up to the mark. Filter through a dry filter- pa per, fill the 200 mm. observation tube, and note the reading of the scale when the field of observation is uniform. The reading divided by 2 equals the percentage by weight of lactose. The w^eights 05.95 and 40.99 represent twice the normal lactose weights of the respective types of instruments. The graduations 102.0 and 101.0 are adopted instead of 100 cc, since the dried precipitated curds from the respective amounts of milk of average specific gravity have a bulk equal to the excess over 100 cc. Determination of Ash. — The ash may be determined by igniting the residue obtained in the determination of total solids, provided no other substance has been introduced into the dish with the milk. The ignition should be conducted at a low red heat until the ash is perfectly white. Then the dish is cooled in a desiccator and again weighed. The difference between this final weight and the original weight of the empty dish represents the amount of mineral matter in the amount of milk taken. Or a larger amount of milk, say 20 grams, may be evaporated with a few cc. of nitric acid and the residue ignited as above. Determination of Proteids. — Having determined the total solids, fat, sugar, and ash, the proteids may be reckoned by difference — that is, by subtracting the sum of the fat, sugar, and ash from the total solids, or they may be determined directly by the Kjeldahl process. 154 POODS. ^vhiL'll dcpcuds upon the couvcrsiuu of the nitrogenous matter into ammonium sulphate, which then is decomposed by an excess of strong alkali, ammonia being- set free. This is expelled by heat, condensed with the acoonipanying steam, and received in acid of known strength. The process is as follows : Into a Kjeldalil digestive flask introdnce a detinite weight, say 5 grams of milk, about 0.7 gram of mercuric oxide, and 20 cc. of sulphuric acid of 1.840 specihc gravity, free from nitrates and ammonium sulphate. Place the flask in an inclined posi- tion and heat below the boiling-point of the acid for from five to fifteen minutes, or until frothing ceases. Then raise the heat until the mixture comes to boiling, and continue the process until the liquid is clear and has a very pale straw color. This will require ordinarily less than an hour. Withdraw the lamp, and drop in, in small quantities at a time, permanganate of potassium, until, after shaking,, the licpiid acquires a permanent green or purple color. This addition is not always or even usually necessary to secure complete oxidation, but since it is sometimes required, it is best to make it a part of the routine. Allow the contents to cool, and then transfer them with about 200 cc. of distilled water, plus sufiicient for thorough rinsing, to a distilling flask of about 550 cc. capacity, fitted with a rubber stopper and a bulb tube connected with a very long Liebig condenser, the delivery end of which is fitted with a glass tube bent at right angles, so that it may dip beneath the surface of the acid into which the distillate is to be received. Add a few pieces of pumice or granulated zinc, or about 0.5 gram of zinc dust, to pre- vent bumping, and 25 cc. of a 4 per cent, aqueous solution of sulphide of potassium, to prevent the formation of compounds of ammonium and mercury, which are not wholly decomposable by alkalies. Shake, and then add of a saturated solution of sodium hydrate, free from nitrates, sufficient to make the reaction strongly alkaline, pouring it down the side of the flask so as not to mix at once with the acid con- tents. Next connect the flask with the condenser, mix the contents by gently rotating, and apply the flame. Distil, and receive the distillate in a vessel containing 50 cc. of decinormal sulphuric acid. When about 175 cc. have passed over, it may be assumed that all ammonia has been expelled, and then the distillate is titrated with decinormal alkali, using cochineal or methyl-orange as an indicator. From the diflPerence in strength of the decinormal acid, the amount of ammonia is calculated, and from this the amount of nitrogen ; and this multiplied by 6.38 gives the total proteins. Detection of Added Water. — One of the most difficult problems which comes to the food and drug analyst is that of determining whether a sample of low standard milk is such because it comes from a variety of cows normally giving such low standard milk or whether the deficiency in quality is due to the addition of water. In deter- mining this question the use of the Zeiss immersion refractometer is of the greatest assistance. This method of analysis was first thor- oughly investigated by Leach and Ly thgoe ^ of the Food and Drug 1 Report of the State Board of Health of Mass., 1903, p. 483. ANAIjVS/S (J I'' MILK. 155 T)cpartm(iiii of \\\v, Mussuclmsclls Shilc- iJoard of IIciilili. " Tlic c/di- ■striiction of IhiH iii,struiri(!iit i.s .siidi llint, jis its iiuinc imjilics, it m;iy b(! directly iiimicrscKl in ;i .solution, tlu; (Jcfrpco of icriac.tioii of wliicli, within limits, may he dctcrmincid upon an arbitrary Hcale." Fig. 5 sliowH this inslrnnicni.' 'rh(! us{' of (Jiis rnctliod, as now cnihodicd in tlic |)iaclicc of the Amo- ciation of Odicial Ati^i-icnllnral ('hcinists, is as followH^: *' 'I'o 100 cubic (;cnlinu>tcrs of milk at a l(!m|)('ra.tiir(! ol" about 20" C. add 2 cubic c(^nti- mctcrs of 25 per cent, acetic acid (sp. gr. 1.0.'i50) in a beaker, anIi;i(c iimIIi'kI ii-ciI in flic food iiiH[K!(!tion Jaborutory of tJic MasH. iStutx; Jioanl ol' IIcmIiIi i-, a- follow- : "Dissolve 72.5 ^raiiiH of (!ryHtalli/(' is sour it should be liltcjred and determination.S of refratition, spe(M(ic (gravity, or ash made upon the s(;rum." The examination of 412 samples of milk of known |)urity fn)m indi- vidual cows, 3G1 being obtained by the Massachusetts Statoard ol' Health, and 51 being examined in the New Jersey Board of Health, gave the following results : The samples varied in total solids from 17.17 per cent, to 10.12 j»er cent., in fat from 7.7 per cent, to 2. .'35 per cent., in solids not fat from 10.05 per cent, to 7.55 per cent. The refractions of the copper serum were found to be between the following limits : Refraction. 36.0 to 36.4 29 samples. 36.5 to 36.9 32 37.0 to 37.4 70 37.5 to 37.9 79 " 38.0 to 38.4 96 38.5 to 38.9 66 39.0 to 39.4 28 39.5 to 40.0 ■ 12 412 samples. The examination of the milk of 28 herds of cows gave the following results : Refraction. 37.1 to 37.4 4 samples. 37.5 to 37.9 12 38.0 to 38.4 5 " 38.5 to 38.7 ._T_ 28 samples. It is not necessary to possess a refractometer in order to examine serum ; in fact, it is a waste of money to purchase one if it is to be used for no other purpose, or unless so many samples are to be examined each day that the saving in time would more than offset the price. The specific refraction of the copper serum . — is not exactly a con- ^ ^ ^ n- + 2 ff stant, decreasing slightly as the refraction grows less, but it is suf- ficiently uniform for refraction yalues between 34 and 38, that if we 1 Lythgoe, Eeport ISIass. State Board of Health, 1908. 158 FOOBS. know the refractiou at 20° C. we may calculate the specific gravity at 20° C. compared with water at 4° C. by the formula — «,2 1 1 !*- \ . -±- = 0.20526. ^2 -j- 2 cP^ The value, of n^ correspoudiug to the scale reading of 36 on the immersion refractometer is 1.34124. Substituting in the above for- nuda we find that d'f^ =: 1.0245; therefore, if a refraction less than 36 indicates added water, the same may be said of a specific gravity less than 1.0245 at 20° C. referred to water at 4° C. The relation between the refraction and gravity of the serum from spontaneously soured milk is expressed by the formula — w2 + 2 ^. = 0.20607. As 38.3 ^ represents the lowest refraction at 20° C, the lowest grav- ity at f C. is 1.0229. For the purpose of studying the influence of added water upon milk a sample of milk above the average in solids not fat and refraction was obtained, and to this sample water was added in varying amounts. The samples were then analyzed and the results appear in the following table : Composition of a Sample of Milk System^atically Watered. Solids (per cent.). Fat (per ceni.). Solids not fat (per cent.). Copper serum. Added water (per cent.). Refraction, 20°. Specific gravity, 20° 40 rfl — \ 1 n2 + 2 ■ 3' Solids (per cent.). 13.18 4.20 8.98 38.5 1.0272 0.20529 6.09 10 11.86 3.78 8.08 36.4 1.0249 0.20526 5.57 20 10.54 3.36 7.18 34.4 1.0233 0.20523 5.05 30 9.23 2.94 6.29 32.4 1.0211 0.20520 4.56 40 7.91 2.52 5.39 ] 30.6 1.0194 0.20518 4.10 50 6.59 2.10 4.49 1 28.6 1.0174 0.20516 3.54 A study of the above table shows that each 5 per cent, of added water lowers the refraction by one scale division, and, therefore, in order to detect 10 per cent, of added water in milk the milk before watering must give a serum refracting below 38. Detection of Added Coloring- Matters. — Annatto. — To about 100 cc. of milk in a cylinder about 1.5 inches in diameter, add a few cc. of sodium carbonate solution, to insure a strongly alkaline reaction during the examination, and then introduce a strip of heavy white filter-paper about 0.5 by 5.5 inches, and set the whole away in a dark place over night. If any annatto color is present, it will, through selective affinity, pass from the milk to the fibre of the paper, Avhich thereby acquires a salmon tint, the depth of which is dependent naturally upon the amount of the substance present. The strip is withdrawn from the 1 Lowest of 125 known purity samples. iM.A^ri': IV A. Strip of Filtei' Paper Dyed by Immersion in Milk Colored with Annatto. B. Same after Treatnient -with Solution of Protochloride of Tin. PLATI': V /■ c . / ■ ■' ..L Z^' L I' 1 ,''n ^ I. <. 0/,' ' L 1-, i ( i ^ «» ■ .. r , -^ \ • ^ ■'■• ;v-.^ Vo ' ,, (- *' , -i.i. J ^ V. Fig. I. Fron-i Un>-oloiv-d ' Fi.i ANALYSIS 01'' MII.K. I-'/) milk, washed ^'ciilly in niiniiii^ \v;ilcr, mid l;ild iipoii ;i |)iy iiicans o(" which all the (-((lor in Ihc atnonnt of milk o|)(!nit(!d upon nuiy Ik; (lonccnt rated in ;i lorni best adapted lor preservation and for exhibits in eourt, is as follows: (.'oaf^iilate from 100 to 150 e,e. of the specimen hy the a|)pli('a)ion ol" lutjit and aeetic acid, and separate (Ik; eoa solution, the (est is delicate to the extent of re- vealing 1 part in 500,000. 2. Method hy Piiloroglucin. — Add to 10 cc of milk in a test- tube 2 or 8 cc. of a 0.10 per cent, solution of ))hlorogiuein and 5 to 10 drops of a 10 ]K'r cent, solution of sodium hydrate, and shake. In the presence of formaldehyde a gradual red coloration appears; otherwise, no such change is observed. This test is said to reveal 1 part in 50,000, but such a claim appears, according to the experience of the author and others, not to be justified. 3. MKTiroD BY Ferric Chloride. — Mix in a porcelain dish 10 cc. each of milk and hydrochloric acid (specific gravity 1.200) and 1 drop of ferric chloride solution. Heat and stir vigorously. If formaldehyde has been added, a violet color will appear before the boiling-])oint is reached, varying in intensity according to the amount present. This process is exceedingly delicate, and will detect 1 part in 500,000 in the fresh condition. 4. Method by Commercial Sulphuric Acid. — This test is ex- ceedingly delicate and very easily applied. It cannot be performed with pure sulphuric acid, since the presence of a trace of iron is neces- sary. If one desires to use a pure acid rather than the ordinary com- mercial grade, the addition of a very small amount of ferric chloride will be sufficient. Take about 15 to 20 cc. of milk in a test-tube and jwur about 5 cc. of the acid gently down the side so that it shall pass under, rather than mix with, the milk. Let stand a few minutes, and then note the color at the junction of the two liquids. If formalin is present, even in the slightest traces, a violet coloration appears at the line of junction. In- asmuch as pure milk will show a somewhat purplish color when in contact with strong sulphuric acid, a color which may readily be mis- taken at first for that due to formaldehyde, and since also the chariing that occurs at the line of junction will often obscure the i-eactiou, the process as originally recommended is somewhat faulty. The objections are removed, ho^Yever, by diluting the strong acid with water so that its specific gravity is reduced from 1,840 to 1.700. The action of the 11 162 FOODS. stronger acid on pure milk is shown in Plate VI., Fig. 1, nliicb shows the dark color due to charring and the purplish color, above spoken of, due to the same cause. In Plate VI., Fig. 2, is shown the appearance of the line of junction of pure milk and the diluted acid. It will be observed that the color produced is but a faint yellow. In Plate VL, Figs. 3 and 4, are shown the zones produced in milk containing formaldehyde in the pro- portions of 1 part to 25,000 aud 1 to 50,000 by the use of the diluted acid. As may be inferred, the reaction is produced rather more slowly with the weaker acid. It is best to allow the contact to continue at least an hour before noting a negative result. 5. Luebert's^ Method by Potassium Sulphate. — Place 5 grams of coarsely powdered potassium sulphate in a 100 cc. flask and dis- tribute over it 5 cc. of milk by means of a pipette. Then pour care- fully down the side of the flask 10 cc. of sulphuric acid (specific gravity 1.840), and allow the whole to stand quietly. If formaldehyde is present, a violet coloration of the potassium sulphate occurs within a few minutes, and gradually diffiises through the entire liquid. If none is present, the mixture will at once assume a brown color, which rapidly changes to black. This test is sensitive to 1 part in 250,000. Cliromates. — Froidevaux^ recommends dissolving the ash of about 10 cc. of milk in a few drops of water acidulated with nitric acid and, after neutralizing with magnesium carbonate, adding a few drops of test- solution of nitrate of silver, whereby a red precipitate, chromate of silver, is formed. As a control test, he recommends taking up another portion of ash with water acidulated with sulphmnc acid, and adding little by little cincture of guaiacum. In the presence of chromates, an intense blue color is produced, which disappears very quickly. This process will detect 1 part in 50,000. Guerin ^ claims greater delicacy for the following method : To 5 or 10 cc. of milk add 2 drops of a 1 per cent, solution of sulphate of copper and 2 or 3 drops of freshly prepared tincture of guaiacum. Pure milk gives a greenish color, while milk containing 1 part in 100,000 will give an intense blue, which reaches its maximum in a few minutes. Methods of Distinguishing between Raw and Cooked Milk. — To determine whether or not milk has been cooked, Saul * recommends the addition of 1 cc. of a 1 per cent, solution (fresh) of ortol (Orthometh- ylaminophenol sulphate) to 10 cc. of milk, and then 1 drop of com- mercial hydrogen peroxide solution. Raw milk develops a red color almost immediately, but milk heated beyond 75° C. remains unchanged. Dupouy ^ gives the following tests : 1. Guaiacol. Equal volumes of milk and a 1 per cent, solution of guaiacol in water are mixed and then treated Avith hydrogen peroxide. 1 Journal of the American Chemical Society, September, 1901, p. 682. =* .Journal de Phannacie et de Chemie, 1896, p. 155. •^ Chemiker Zeitung, 1897, p. 174. * British Medical .Journal, March 24, 1903. * Journal de Pharmacie et de Chemie, 1897, p. 397. PLATL VI I- 1 (J. I \nn. n Fic|. 1. Coloration Produced by Con'-"-i''~-"-=" ' -^n i ,^i , , i ,-; . a,; ■ Contaet, witU Pure Milk. Fui. '"^ r" ■ .ation Produced by Suipimrie Ae; ih Pure Milk. Fie), y. Coloration Produced by Sulphuric Acid of Sp. Gr. 1.~j2 with Milk Containing I Part of Formaldehyde in 25.000. FicT. ^- Coloration Produced by Sulphuric Acid of Sp. with Milk Containing 1 Part of Fornialdehyde contact i n Contaet in Contact ANALYSIS OF MILK. \('>''> TIk! iiniri(!(li;it(^ product ioii of ;i yellow coloi- iii drops of hy(lro}r(!ii |)(!ro.\id('. If th(! milk Iwis not hccn hoilcd, a row; color im- m(!; |)(M'iods. In rancid hnticr, hiityric and other acids arc Hhcralcd, and otluii-s, as forniicr, an; formed hy al)sorj)tion of oxy^rvu. Under Konio nnnsiial coiKhtions not wholly un(h'rstood, huttor, withont bccom- ini>' rancid in tiu! usual sense, iiiiderabnitic, constitntc about 92.25 per cent, of the whole ; and those of the solulile volatile acids, butyric, caproic, caprylic, and capric, make up the remainder. It is to the second group that butter o\ves its distinctive flavor. The amount of water depends largely upon the thoroughness with which the buttermilk is worked out. In order that more water may be held, and thus a greater profit realized, some makers employ gelatin as an adulterant. One gram of this substance will take up about 10 grams of water, and, when mixed with butter in the right ])ropor- tion, will hold water in the above ratio without affecting the consi.stence injuriously. Others employ glucose both for this purjjose and as a preservative. The salts include those natural to milk and those added for the pre- vention of rapid decomposition. The usual addition is common salt, but the use of boric acid and borax is extending gradually. Apart from the use of preservatives and of ageuts to assist in retain- ing water, butter is not much subject to adulteration, exce}>tiug in the sense that substitution of an article of less value when butter is called for is a form of adulteration. This substitute is known variously as artificial butter, butterine, oleomargarine, and marg-arine. Under the United States statutes, all butter or substitutes therefor made to resemble it, containing fats other than cream, shall be knoMTi as oleo- mai'g-arine. Following the original process, oleomargarme is made from fresh beef suet, which, after being cooled, washed, and cut into very fkie pieces by machinery, is subjected to a temperature of about 11 C^ F. 166 FOODS. for several liours, in order to separate the fat from the tissue. It is then drawn off and kept for a time at 80° to 90° F., at which tem- perature the stearin solidifies, and then is separated by pressure from the "oleo-oil." The latter is churned with milk or witli milk and gen- uine butter, colored witii annatto, and otherwise treated like butter. At the present time, olet)margarine is made not alone from beef suet, but to a much greater extent from " neutral lard," a product of leaf lard. Cotton-seed oil is used to some extent, but naturally it is not so well adapted to the purpose as the solid fats. Oleomargarine has been misrepresented to the public to a greater extent probably than any other article of food. From the time of its first appearance in the market as a competitor of butter, there has been a constant attem]it to create and foster a prejudice against it as an unwholesome article made from unclean refuse of various kinds, a vehicle for disease germs, and a disseminator of tapeworms and other unwelcome parasites. It has been said to be made from soap grease, from the carcasses of animals dead of disease, from grease extracted from sewer sludge, and from a variety of other articles equally unadapted to its manufacture. The publication of a great mass of untruth cannot fail to have at least a part of its desired effect, not solely on the minds of the ignorant, but even on those of persons of more than average intelligence. So a prejudice was created against this valuable food product, but it is becoming gradually less pronounced. The truth concerning oleomargarine is that it is made only from the cleanest materials in the cleanest possible manner ; that it is equally as wholesome as butter ; and that when sold for what it is and at its proper price it brings into the dietary of those who cannot afford the better grades of butter an important fat food much superior in flavor and keeping property to the cheaper grades of butter, which bring a higher price. Oleomargarine cannot be made from rancid fat, and in its manufacture great care mast be exercised to exclude any material how- ever slightly tainted. Oleomargarine is not and cannot be made from fats having a marked or distinctive taste, and its flavor is derived wholly from the milk or genuine butter employed in its manufacture. It contains, as a rule, less water than does genuine butter, and consequently any difference in food value is in its favor. It imdergoes decomposition much more slowly, and, indeed, may be kept many months without becoming rancid. Much has been said concerning its digestibihty, and alarmists have gone so far as to claim that it is very indigestible, and likely to prove a pro- lific cause of dyspepsia, quite forgetting that the materials from which it is made have held a place in the dietaries of all civilized peoples since long before butter was promoted from its position as an ointment to that of an article of food. Many comparative studies have been made on this point, and the results in general have shown that there is little if any difference. H. Liihrig ^ has proved by careful experiment that the ^ 5^itschrift fiir Untersuchung der Nahrungs- und Genussmittel, June, 1899, p. 484. lill'I'TKIl. 107 two iivv. (,() ;ill inlcnls :iii(l purposes r-XHcllv .'ililsc in point, oC dij^f.-ti- l)ilily. ()l<;()niiirji;!irin(! lias been (lie siihjcci oC a vjist Jiriiouiit of nrHtric^ive l(!^isl!ili()n vvlici'cvcr it. is made or sold. This Iijih br-cn psLsscd in tiu; iii(,ercs(, of" dairynicM and Ix-cransc of llio («IH(! willi wliidi it rnav Ik- sold (raiidulcndy as hnlicr at hntfcr j)ri(;(!H. To the practice of fraud in its retail sale, is due wvy lart^ely tlie passage of proliihitivc lawH, many of vvliieli, however, have been declared iinconstitiitional. In Massadlinset.ts, for example, it had at one tim(^ a verv larjfe sale, and in tli(^ v\\\ of l)Oslon alone were nearly 200 licensed dealers. IJiit tin* imomit of fraudulent dealing was so ^reat that the J^e^islaturc pas.s'^) <:c. ol" l)(»il('(l wjifcr, .'iddcd :il firsl in very nrnall nrnouiitH to piXiVcsnt ioiiniinn-. 'I'licn 5 rv. of" dilute suljthuric ju-id (200 cc. in 1000) iiro iiddcd, Mud (lie |)i(|):ii;il ion is r(;:idy lor ininicdiiite dihtiila- tion. Distil 110 cc, niix tlioroiijiliiy, juid jkiss ihrouMli ;i dry filtiil it should \)v. snid tliat the [)rfK:(' ;i scjilc division lor v;\f\\ lU'^rvi' ( ". Tlif follfjwin^ tabic hIiows IIk; nuixiiiiiuii Yvin\'\u\r for |)iirc huflcr.s al dWWmwt U'.u\- jKM'aliircH : Temp. He. fllv. 'rem p. 8c. dlv. Temp. 8c. dlv. Temp, SC, dlT, 25° r)'lS^ ;5i° 49.2 37° 45.9 43° 42.r, 26 r)i.<,) ;{2 4H.(; : 38 45.3 44 42.0 27 51.4 HS 4K.1 39 44.8 45 41.5 28 no.H 34 47.5 40 44.2 29 r)0..s 35 47.(1 41 43.7 30 49.8 36 4(1.4 42 4.3.] There are other processes for the investigation of the character of butter-fat, including tlic determination of the specific gravity, melting- point, iodine abKori)tion lunnlxir, and .saponification of|nivalent ; but for all j)racticnl pur])ose,s the dctcnnination of the refractive index or of the volatile fatty acids is ordinarily sufficient, and the other determi- nations are merely corroborative. CHEESE. United States Standard. — Standard cheese is the sound, solid, and ripened product made from milk or cream by coagulating the casein thereof with rennet or lactic acid with or without the addition of ripening ferments and seasoning, and contains in the water-free .'^nb- stance not less than 50 per cent, of milk fat. By Act of Congress, approved Jiuie 9, 1896, cheese may also contain added coloring matter. For thousands of years cheese has been known as a very valuable food, and much attention has been paid to different methods of manu- facture. At the present time many varieties are made, their nature depending upon that of the raw material, the method of producing the curd, the proportions of the several constituents, and the method of ripening. Most varieties are made from cows' milk ; some are made from that of ewes, and others from that of goats. The milk is used either in its natural condition, or skimmed, or with the addition of cream. Generally, it is used in its natural condition. Whatever the kind, the following is the general process of manufact- ure. The milk, with or without coloring matter as desired, is heated to 80° F. or above, and then curdled by means of rennet or by the acids formed by the ordinary milk bacteria. Usually, rennet is em- ployed ; sometimes, sour whey. The coagulation should be complete in from forty minutes to an hour. Too rapid coagulation causes the curd to be hard, tough, and unsuitable for the subsequent manipula- tion ; too slow action produces a soft curd difficult to work and not uniform in character. After the process of coagulation is complete, the curd is cut or broken into small pieces, and the whey is drawn off. Then the curd is gathered into a heap and covered, and allowed to stand for an hour or longer, during which time its increasing acidity assists in its hardening and promotes the separation of the remaining 174 FOODS. whov. "\Vhen the curd has attained the proper consistence, it is placed in a cheese press and subjected to t^radually increasino- pressure, and after this process is completed it is removed to the curing- [)lace. For the proper ripening of cheese, it is essential that the curd be of the proper consistence throughout, and that only tlie favorable organisms be present, and these in not too great abundance. The curd produced by the action of sour whey is highly acid and inclined to be greasy. Owing to its high degree of acidity, it is not a favorable ground for the growth of many of the bacteria to which is due the production of the diifereut kinds of flavor, and so the number of varieties possible of manufacture by sour whey is limited. Rennet, on the other hand, produces a curd which is elastic and not greasy or sticky, and which is a good culture medium for the bacteria whose assistance is needed. It acts best in milk which is slightly acid, for if the milk is neutral or only very slightly acid, the coagulation proceeds very slowly and the curd will not contract sufficiently to expel the whey ; if the milk is too acid, the process of coagulation is too rapid and the product too tough. A soft curd retains too much whey, and the fermentation of the milk sugar of the whey causes " huffing," or swelling, for the prevention of which, preservatives sometimes are employed. The bacteria concerned in the process of ripening exist in the original milk or in the air of the place of manufacture. Sometimes the varieties which produce cheese " faults " gain a foothold on the premises, and can be eradicated only by means of thorough cleaning and disinfection. The ripening process is carried on at about 70° F. It is essentially a process of decomposition, in which enzymes, bacteria, and moulds are concerned ; and for the production of the same kind of cheese the same varieties of organisms must be present, and the particular variety producing a particular flavor must find the conditions such as are favorable to its predominance. It is not possible to start with milk that is entirely sterile, and then to inoculate with the par- ticular varieties wanted, since to sterilize milk completely requires the application of such a degree of heat as will produce changes in the casein, interfere with the proper action of the rennet, injure the con- sistence of the curd, and destroy the enzymes. Ripening does not proceed satisfactorily when the curd has been produced through the action of acids. In ordinary ripening, the casein is attacked by the organisms present, and ammonia, leucin, tyrosin, and several kinds of fatty acids are produced. The latter unite with the lime salts, which up to this point have been in combination with the casein. The acids formed include butyric and valerianic. From the lactose, we have, in addition, lactic acid. The process goes on at differ- ent rates with different kinds of cheese, and it may be short or long. In the production of certain forms of American and English cheeses, the individual specimens are sealed hermetically in tin boxes and kept at a favorable temperature for as long as four years, the boxes being turned each day. The ordinary grades of cheese, however, undergo comparatively short periods of ripening. CIIKKSK. 1 76 Composition of Cheese. — Tlu; (toinposifion (»C vhccMv. vjirics vory \n\\c\\ ;ic(',(»i(liii^' (<» tlic iLiidrc of llic favv riiiilcrinl und flif proff^H of iiiiumfiM^lin'c. Tlic liil shows (lie ji;r(!nt(!.st vari.-itioii in ainoiini, •M'X'AWiVuv^ as lli(i (iliccsc, is made from wlioh; rnilU, Hltics in general is forbidden. In some parts of Germany, bean meal and potatoes are used to some extent as adulterants, and there and elsewhere a great variety of substances are said to have been used to a greater or less extent in times gone by. In general, it may be said that, aside from lard and other foreign fats, the only adulteration of any importance consists in the admixture of preservatives. These are added more commonly to skimmed milk cheeses than to those of good quality. Analysis of Cheese. Determination of Water. — Cut the specimen into small bits or thin slices. AVeigh out about 5 grams in a platinum dish containing sand or asbestos fiber, and dry to constant weight. Determination of Ash. — Ignite the dried residue at as low a tem- perature as possible, and, after cooling, note the increase in weight over that of the dish and its original contents. Determination of Fat. — Triturate about 25 grams of the specimen in a mortar with an equal bulk of fine beach sand. Transfer the whole to a Soxhlet extractor, and proceed in the manner described under the Analysis of Milk. Determination of Proteids. — Proceed in the manner given under Analysis of jSIilk, using about 2 grams of the sample. Determination of the Nature of the Fat. — For the detection of foreign fats, the method of procedure is the same as described under the Analysis of Butter, after obtaining the fat in a pure condition. The residue obtained in the determination of the amount of fat will serve for this purpose. Cheese as a Cause of Poisoning. For many years, cheese has been known to be an occasional cause of single and multiple cases of poisoning, and various theories concerning the nature of the poisonous agent have been promulgated. It was not until 1884 that the cause was revealed by Professor V. C. Vaughan, whose attention was drawn to outbreaks in Michigan during 1883 and (iiii':i':si<: as a caiis/': of roisosiNd. 177 1884, in wlilcli more lliaii .'>()() jKsrKoriH wen; 'AYvrXfA. lie trartcd flic wli<)l(! tr()iil)l(( lo l,w('lv(! (liirciciit, rliccscH, (Vf)rri HCNcral of \vlii<'li he i.solnlcd tli(! |)oi,soiioii.s juiticiplc, a ploriiaiii, (o wliicli lie ^avc tlic iiaiiic '' tyro((>xi(!oii." Tlic syinphtms olisccxcd In (lie ontbrcMk" rcfi-ncd lo incliKk^d voniitiii<^, (lian'li(i';i, ;il»(loiniii;il |i;iin, (li\iic-s jiihI coiK^lricfioii of tlu! tlii'oal., f('(!l)l(! and iirc^nl.-ir pulse, ;iiid nuiiked esanosi.s. In ,soni(! (!as(!M, voiniliii^ iiiid (liaifli(e;i were followed hy marked nervonH |)rosl ral ion. In some (Ik; pnpils were dilaled. Williin a sliorl, (inu! after V:in<;lian',s dis(;overy, llic pftison was found by Wiilkiee, ' in some (ilieese (li,i( was i\\(\ cause of poisoning,'- of not Icsh than 50 ]KM-s()ns out of ;il)on( (10 w lio had <'a(en of it. The onset appeared in from two to four hours. The most e(»nstant and sevcro .symptorn.s were vomitiuii; and ehills. "^riiese were sueeec^ded by severe cpipistric pain, (■,ram|)s in the le<»;s and feet, ])Ui'fz;in^'' and ^rij)in^'-, numbnc^ss esjK-- cially marked in the le^s, and very m;irked ])rostralion. N'omitin^- and diarrJKra- lasted from two to twehc hours ; ehills and ei-amps from one to two hours. No deaths occurred, and all recovered within three day.«. The severity of the symptoms bore no relation to the amount ejitcn ; some of the severest cases were of persons who at(! })ut s])arinLdy. More recent work by Vaughan and his associates and others has demonstrated that tyrotoxicon is not the only cause of cheese-, milk-, and ice-cream-poisoning, and that it is, indeed, a somewhat rare poison. Other toxic substances have been isolated from cheeses that yielded no tyrotoxicon. Section 4. VEGETABLE FOODS. The vegetable foods may conveniently be divided into several classes as follows : 1. Farinaceous seeds : (a) Cereals ; (/;) Legumes. 2. Farinaceous preparations. 3. Fatty seeds (nuts). 4. Vegetable fats. 5. Tubers and roots. 6. Herbaceous articles (" vegetables "). 7. Fruits used as " vegetables." 8. Fruits in the narrower sense. 9. Edible fungi. 10. Saccharine preparations. The words fruit and vegetable are capable alike of broad and narrow meanings. In the strict sense, the cereals, legumes, nuts, and manv of the articles commonly called vegetables are fruits ; but popular usage has narrow^ed the latter term to include the pulpy substance enclosing the seeds of various trees and plants, and only such as are pleasant to the taste and edible in the raw state, with the single exception of the quince, which is edible only when cooked. A'egetables in the ordi- nary sense include any part of herbaceous plants, as the stem, root, ^Medical News, Julv 16, 1S87, p. 69. 12 . . 1- 1 78 FOODS. leaves, and frnitv products used commonly in the cooked state or in the form ot" salads. Thus, in the popular usage of the terms, squashes and melons, which are the fruits of plants of the same family, are classed respectively as vegetables and fruits, and the cereals and nuts are classitied under neither head. First in importance of vegetable foods are the farinaceous seeds ; they are of very higli nutritive value and easily digested. 1. Farinaceous Seeds. {(() CEREALS. The cereals include wheat, rye, barley, oats, corn, buckwheat, and rice. They are very largely starchy, and agree in general composition ; but they differ in the proportions in which their several constituents are present. These include proteids, carbohydrates, ether extractives, mineral matter, aud moisture. The proteids include a large number of closely related compounds, as yet only imperfectly studied, which will be mentioned in the consideration of each member of the group. The carbohydrates include those which are soluble, sugar and dextrin, and those which are insoluble, starch, cellulose, pentosans, and gelactans (H. W. AViley). The ether extractives include fats, resins, chlorophyll, and volatile oil " which constitutes the source of the odorous quality possessed by the grain " (AViley). The mineral matters are chiefly phosphates of calcium, and magnesium, silica, and salts of sodium and potassium. The cereals contain also certain ferments, the most impor- tant of which, and the only one which has been studied with any thoroughness, is diastase. This acts upon starch, converting it into sugar. The others include some which act upon the proteids. Wheat. Wheat is classed very properly as the most useful of the vegetable foods. The grain consists of a hard outside layer which is indi- gestible and useless as food, and the cortex, softer and more friable, which yields flour of high nutritive value. The hard outside layer, which constitutes the greater part of bran, irritates the alimentary canal, and, while useful to some extent in conditions of habitual con- stipation, should be avoided in all irritable conditions of the bowel. It causes waste by unduly promoting peristalsis, so that much of the nutritive portion is hurried along in an undigested condition. The proteids of wheat include, according to Osborne and Voorhees,^ a globulin, an albumin, a proteose, gliadin, and glutenin. The two last-mentioned constitute between 80 and 90 per cent, of the whole ; in the presence of water they unite to form the very important substance gluten, so essential in the conversion of flour into bread. According to Wiley, they unite in almost equal proportions ; but in the opinion of E. Fleurent,^ the closer the composition of gluten approaches the 1 American Chemical Journal, XV., p 392. ^ Comptes rendus, 1898, p. 126. PLA'J'E VII Wheat Starch, x 285. o r ^ Rye Starch. X 28§. w 1 1 HAT FLorrn. 170 rol.'iiioii of 25 p;irt,s of •rliilcnin lo T") of j/li:i(IIii, \\]<- iiiorr; v;i]iial»l«; the (lour. The carl)()li)(lr:i(cs coiiHliliilc (lie L'ic.'il'i' |';ir> "f wliciit aH well jls of the other cci-i'Mls. They inchidc -lnifh, liy llir the most important, celhiloHc, sii- in flonr that lias been snhjected (o heal, as, (or instance, in tiie hakin^'' of rraekerH. The wide variations in siz<^ are illnstrated in Tlatc \'II., I''i}r. 1. The oth(>r earl)(tln(lr;ites exist in hut V(>ry small projxtrl ions. Composition of Wheat. — The vast nnmlHr of analyses of wheat show important variations in the |)ei-('cnt;i^e of its several constituents, for its ([uality is indnencied (ronsidenihly hy clinijitc, character of the soil, and other conditions. According to J I. \V. Wiley,' a ty|)ical American wheat of the best quality should yield api)roxiniately the following results : Moisture lf>-W) Proteids 12.2o Ether extract l-7o Crude liber -'-40 Starch, etc "I'-'-t Ash • 1-70 100.00 These figures do not vary materially from the averages of a large number of analyses of samples of miscellaneous origin compiled by Konig, excepting in the proportions of moisture and starch, in which respects Wiley's typical specimen shows superior value, being less rich in the one and richer in the other constituent. Wheat Flour. In the manufiicture of flour, the wheat kernels are subjected first to a process of thorough cleaning, and then are cracked, crushed, and ground until the required state of fineness is attained, the bran and other undesirable portions being removed by bolting. All flour is by no means the same in composition and quality ; in fact, several gratles of flour may be made from the same wheat by the employment of diflerent processes of manufacture. Flours are graded according to color or appearance, those which make the whitest bread ranking high- est, although not equal in nutritive value to those classed as low grade. The flours of the several grades are known commercially as "■ patent," " family," " bakers'," and other names which to the public have no special significance. Typicid flours of the grades known as '"high- grade patent " and '• bakers' " should have, according to Wiley, approximately the following composition : 1 U. S. Department of Agriculture, Division of Chemistry, Bull. 13, Fart 9, p. 1189. 180 FOODS. Moisture. Proteids. Ether extract. Carbohydrates. Ash. Patent 12.75 10.50 1.00 75.25 0.50 Bakers' 11.75 12.30 1.30 74.05 0.60 The average compo.sition of 210 samples of wheat flour of high and niediuni grades and of grades not indicated is, as given by Atwater and Bryant, as follows : Moisture 12.00 Proteids 11.40 Ether extract 1.00 Carbohvdrates 75.10 Ash . '. 0.50 100.00 Thirteen samples of low grade averaged as follows : Moisture 12.00 Proteids 14.00 Ether extract 1.90 Carbohvdrates 71.20 Ash . ■ 0.90 100.00 It will be noticed that the high grade flours are poorer in proteids and fat, and correspondingly richer in starch. Other grades of flour include those known as graham and entire wheat. Graham flour is understood generally to be a product containing all of the constituents of the original grain in their same proportions. When it came first into use, such, indeed, it was ; but at the present time it is an unbolted or partially bolted product of thoroughly cleaned and dusted wheat. Entire wheat flour is understood also to contain all of the original con- stituents of the grain, but is, in fact, made from wheat deprived of its outer coverings. It makes a somewhat dark-colored bread which is very palatable. Parenthetically, it may not be out of place to refer here to the absurd views maintained by a large part of the community as to the superiority, from a hygienic standpoint, of foods containing all of the constituents of the cereals from which they are prepared. It is difficult to understand how the nutritive value of any food can be increased by the retention of matters which are completely indigestible and to a certain extent irritating to the digestive tract. It is argued that an all-wise Creator made wheat, for example, in the form in which we see it, and that it is not for us to attempt to improve it, as we think, by discarding the outer layers. But this sort of reasoning might be extended so as to favor the consumption of the peel of oranges, the bones of fish, the feathers of birds, and other innutritions and undesir- able waste ]:)roducts. Preparations of Wheat Flour. — Bread. — First in importance of the preparations of wheat flour is bread. In the broad sense, bread includes all forms of baked flour, whether leavened or unleavened ; in the common use of the term, it includes only those in which leaven- ing agents are used, the other forms being designated as pilot bread, crackers, biscuits, etc. WHEAT FLOUR. 181 Tho adiipinbility of wlicjil- (lour for ItrcMl-mukinK is iliic to itH j^luton C()iilressr'd in the hand, it will keep its shape on bein}>; released. In thin^ rcriiicnlnlivc clinn^cs ilml me. li;i.^t<;ii<:il l)y the body t<;rn- jMinitiirc, willi (•(ni,s('(|ii(!iit (tvoliilion >>i' }i:;iHoouH pHKhuttM wWu-h muwj lliiliii('ii(!(! ;iii(l (lisconirofl, uiid of irritiiliii^ cotiipoiiiKls \vhi<-h iiidiKu; ubdomiicil piiin :uid (Hiirrhfr!:!. lircad iriudc fruiii old :iiid p:irti;dly HpoihMl (lour is likiily to h;i\'c ;i distiiKjtly Hour insU'. and to \}c nnwhoh-- Horne in \\\v, inaiiiicr above; dcs(;fibim;ai). — Since whcat flour itself is of vari- able coin])()sitioii, and since in (he domestic inannfactiin! of any artiftle of food the jirocesses employed an; .subject to slij^ht or eonsidendde variations, analyses of wheat bi-ead necessarily must show ^rwit differ- ences in the pi-oportions of the several (ronstitnents. Averages obtained from cxandnation of samples of all sorts and of miseellaneons ori^dri can hardly represent the composition of bread of {^ood avoraj^c or high qnality. Toast. — In the process of toasting, a large part of the moisture is drivcni oif, the surfaces are scorched, greater tirmness is acquired, and the product is more easily digestible. Good toast cannot be made from perfectly fresh bread, on account of the moisture present, which cause.s soffiriuess : it can be made only from bread at least a day old. The slices should not be thick, since then, while tlie surface is scorched, the interior acquires increased softness under the action of lieat and be- comes less digestible than the original bread. Rusks are much like toast. Instead of being subjected to the direct a(!tion of hot coals, the brejid slices are baked for a time in a modemtely hot oven. Pulled Bread is the crumb of freshly baked loaves pulled out in small masses and baked agahi like rusks. Crackers, or biscuits, are preparations made from unleavened dough and baked so dry as to be brittle. They keep well for a long time without losing their palatability. If not properly stored and cared for, they may, of course, become damp, musty, and mouldy. In composi- tion they vary but little from the flour of which they are made ; they are drier, and what they lack in moisture they make up in fat, which, in the form of butter or lard, is added to prevent them from becoming too hard and dry. Other preparations of wheat flour include cakes, which, on account of the contained butter, eggs, and sugar, are richer than bread ; pastry, which, on account of its content of lard, is more difficult of digestion ; and flour puddings, wdiich, being very "■ close," require nmch time for digestion and often cause sensation of weight and oppression. Macaroni, spaghetti, and vermicelli are preparations made with haixi wheat rich in gluten. The flour is made into a stiff paste with hot water, and the compound then is pressed through holes or moulds in a metal plate and dried. They are exceedingly nutritious, but they are not as easy of digestion as other preparations of wheat, on account of their closeness. They were flrst made on a small scale in Sicily, but 184 FOODS. now are produced in enormous amounts in Italy, France, Cermany, and otlier countries. In their manufacture, American wlieats are not held in hifjh esteem, containing: not sufficient gluten and too much starch. The best wheat for the jnirpose comes from a particular district in Russia and from Algeria. Ft)rmerly, a grain from southern Italy was reo-arded as the most suitable. Adulteration of Flour. — Up to within comparatively recent years, flour has not been much subject to adulteration. Occasionally, certain mineral substances, as magnesium carbonate, gypsum, and ground chalk, have been reported in European samples ; but such have been employed as adulterants very rarely, if, indeed, at all in American flours. Alum has been added sometimes to flour of inferior quality to improve its color or to check beginning decomposition. Whether this addition is objectionable from a hygienic standpoint is a subject over which there is decided disagreement. It is believed by some that the amount of alum added is sufficient to exert an injurious effiict on the digestive tract on account of its astringent action, and to bring about constipation and dyspepsia ; others believe that it can do no harm whatever, either to the consumer or to the nutritive value of the food ; and still others hold that, while it is not injurious to health, it lessens the nutritive value of the flour by forming insoluble aluminum phosphate, and thus depriving the system of the phosphates which otherwise would be absorbed. It is a fact that flour, treated with alum on account of begmning deteriora- tion, has caused untoward effects, but it would be impossible to deter- mine how much influence should be ascribed to the alum and how much to the products formed by the fermentative processes in operation before the adcUtion. The weight of evidence, however, is in favor of the view that alum is not incapable of producmg injury when taken into the system habitually in small amounts, and that it should be excluded from all articles of food intended for man. On account of the growing tendency to mix other mill products of inferior value with wheat flour, such, for instance, as rye and corn flour, a law was passed by Congress in June, 1898, to meet the evil, and mcidentally to make it a source of revenue. All adulterated flour is, by the act referred to, designated as " mixed flour," which term " shall be understood to mean the food product made from wheat mixed or blended in whole or in part with any other grain or other material, or the manufactured product of any other grain or other material than wheat." Under the provisions of the law, all persons engaged in the business of making mixed flour are required to pay a special annual tax, every package must be labelled plainly, the names of the ingred- ients being set forth, and upon every package of 196 pounds a tax of 4 cents shall be paid. Under the regulations of the Treasury, the term " mixed flour " is held not to include " the milling product from corn, rye, buckwheat, rice, or other cereals than wheat put upon the market as the flour or meal derived from such cereals, although the product may contain a percentage of wheat flour." nVE. 185 Tlio cl(!t(!cii(tn of ()tli(!r cfTC'ils !ui(l stiintlicH if) wheat flour i.s aox'orn- [)lisli^(;I, 70 y)er cent, alcohol (;on(ainin^ 5 p<^r ccni. of hydi-ochloric acid remains colorlesH •dllvr heino^ used to (ixtract pun; wheat or rye, turns pale yelh)W if barley or oats be prescul, and orarige-y(;llow if mixed with pea flour. Bleaching of Flour. — Witliin the last f(;w years there has been in- trodiKu^l in the (lonr indnst-iy a process by whidi flour is blejirihwl throngh tlu; use of nitrotij(!n peroxich;. Ac(;ording to Leach,' " Nitro- gen peroxide destroys almost immediately the yellow color which is associated with the fat of the flour, thus increasing the whiteness of the ])rodu(!t. It also combines with the moistun; of the flour, forming nitrons and nitric acids, the nitrous acid (free or combined] being espe- cially noteworthy because of the (!ase of detection." Whether or not this bleaching of flour constitutes a menace to the public health is still undecided. As a test for the bleaching of flour. Leach" gives the following test, based on observations of Alway : " Gasolene test. Place 25 grams of the flour in a four-ounce, wide- mouthed, glass-stoppered bottle, add sufficient gasolene to nearly fill the bottle, shake, and allow to settle. If the flour is unbleached the gasolene will be distinctly yellow; if bleached, it will remain nearly colorless." Rye. In external appearance, rye presents a close resemblance to wheat, but the kernels are darker in color and smaller in size. It is bv no means so important as wheat as an article of food in this countiy, but in some parts of Europe it constitutes the main food supply of the petisantry. According to Wiley, a typical American rye should have approx- uuately the following composition : Moisture 10.50 Proteids 12.25 Ether extract 1.50 Crude liber 2.10 Starch, etc 71.75 Ash L90 100.00 American rye is smaller than that groAvn abroad, and contains less moisture. The proteids of lye are more like those of wheat than those of any other cereal, and in consequence rye stands next to wheat in adaptability for bread-making. The yield of gluten is inferior in amount to that obtainable from wheat. ^ Food Inspection and Analysis, 1909, p. 325. a Ibid., p. 321. 186 FOODS. The starch of rye is much like that of wheat. The granules are rather more variable in size, the smallest of each kind being about equal, but the largest of rve somewhat surpassing those of wheat. There is but one point of difference in microscopic appearance which has any value in detecting the admixture of rye with wheat, namely, that a certain fair proportion of the larger sized granules of rye present irregular crosses or fractures. This is illustrated in Plate yil., Fig. 2. Bread made from rye flour is but little inferior in nutritive value to that from wheat, but it is less pleasing to the eye, being of a brownish tint, and it has a peculiar sour taste, not altogether agreeable on first acquaintance. Not uncommonly, its use by one not habituated to it causes a tendency to diarrhcea, which, however, is soon overcome. Barley. This important cereal is used mainly in the manufacture of beer, and but to a limited extent as a food. Deprived of its husk and rounded and polished by attrition, it is known as " pearl barley," and in this form is used more or less in the preparation of barley-water, a drink for invalids. In its composition, barley is very similar to wheat and rye, but as its proteids yield no gluten, it cannot be made into bread. It is mixed sometimes with wheat flour for purposes of bread-making, but the product is less palatable and less digestible than ordinary bread. Wiley gives the following as the approximate composition of a typi- cal American unhulled barley : Moisture 10.85 Proteids 11.00 Ether extract 2.25 Crude fiber 3.85 Starch, etc 69.55 Ash 2.50 100.00 The proteids include, as in all cereals, a number of complex sub- stances, chief of which is hordein. The starch granules are like those of wheat, but are less variable in size. (See Plate VIII., Fig. 1.) In the manufacture of malt from barley for brewing, a peculiar nitroge- nous product, diastase, is formed, which has the property of converting starch to sugar. Oats. Oats are much used as human food in the form of oatmeal, which is the product of grinding the kiln-dried seeds deprived of the husk. The meal has a peculiar taste, which is both sweet and bitter. The composition of unhulled American oats, as given by Wiley, is as follows : /^ pj.A'i'ii: VIII F\n.\i ■^ Barley Starch. : 28?^ Oats Starch. ^ 286. CORN. 1H7 MoiHliin! 1"W l>n.t..i K(lirr(^xl.i!i('l '♦••''''' (!ru.l., r.l..,r lii-'X' Stjiivh, (■(,(; -'^-^^^ AhI. •"-■^" lod.oo The mciin coinposil.ioii (»f oatmeal, luironliii^ to lilylli,' i- as follow'.s! Moistures l^--''-^ IVoU-i.ls 11.7» ]<^il «.04 Ku^iir 2.22 I)(\x(riii ;iii(l K">'i 2.04 Stiucl. •'Jl-17 Fiber 10.83 Ash 3.05 100.00 The proteids of oats yield no j;luten, and hence this artielo of diet cannot be made into bixiad, thouii;h with water it eun h(! made into thin cakes, which arc most ])alat;ib]e. V-At is present is greater abundant than in any other eerciil. The starch grannies are very small i)f>ly- hedra which show neither hilnm nor concentric rings. They tend to adhere together in masses of variable size, which are disintegrated easily by tritnration in a mortar. The single granules are shown in Plate VIIL, Fig. 2. Oatmeal is a very nntritions article of diet, used largely as a break- fast food in the form of porridge. It has a somewhat laxative action, and, therefore, should not be eaten in irritable conditions of the bowel. It is also likely to disagree with some dyspeptics, because of its ten- dency to cause acidity and heartburn. Com. In the American usage of the word, corn includes the several varie- ties of Indian corn or maize. In England, the term is applied gener- ally to wheat, rye, oats, and barley, and more specifically to wheat ; in Scotland, it commonly means oats. In the United States, com is in many ways the most important of the cereals, constituting in some parts of the country the chief bread food, and being the main source of starch and glucose. The chief varieties are dent corn, showing a depression in the outer end of the kernel ; flint corn, having a hard smooth exterior ; sweet corn, rich in sug-ar and shrivelling when ripe ; and }>op-coru, a very flinty variety with small kernels, which contain a considerable amount of oil, which, in the process of roasting, explodes and causes the extru- sion of the starchy interior in the form so universally familiar. The variety in most common use, from which the several kinds of meal, hominy, and samp arc derived, is the flint com. Hominy is the prod- uct obtained by grinding coarsely the kernels deprived of the hull by soalving. Samp is the whole, or practically the whole, of the kernel ^ Foods: Their Composition iiiitl Analysis, Loudou, 1S96, p. 210. 188 FOODS. minus the germ and hull. Indian meal, or corn meal, is the product obtained hv iirindini;,- the kernels betM'ecn stones or by other ])rocesses of milling-, and removing- more or less of the bran by sifting or bolt- ing. According- to the process employed, we have coarse and fine, and ■white and yellow meal. Prepared without removal of the germ, which is rich in oil,, the product is prone to become rancid and mouldy on keeping. From a large number of analyses, A\'iley deduces the following as the approximate composition of typical Indian corn : Moisture 10.75 Pioteids 10.00 Ether extract 4.25 Crude fiber 1.75 Starch, etc 71.75 Ash 1.50 100.00 The average of 19 analyses of samples of sweet corn by Clifford Richardson, quoted by Wiley, shows : Moisture 8.44 Proteids 11.48 Ether exti-act 8.57 Crude fiber 2.82 Starch, etc 66.72 Ash 1.97 100.00 The composition of fine meal is given by Wiley as follows : Moisture 12.57 Proteids 7.13 Ether extract 1.33 Total carbohydrates 78.36 Ash 0.61 100.00 The lowered percentages of proteids and fats here shown are due to the removal of the germ, rich in fat, and of the finer envelopes, rich in proteids. The proteids of corn, as determined by Chittenden and Osborne, are made up of several globulins, including myosine and vitelline, two classes of albumins, and two of zeins. The starch granules are poly- hedral with rounded angles, and have a punctiform, sometimes stellated, hilum. They are much larger than those of oats, which they resemble somewhat in form. They are shown in Plate IX., Fig. 1. On account of its deficiency in gluten, corn meal is not well adapted to the making of leavened bread, but it is used in many forms of sub- stitutes therefor. It is mixed with salt and water, sometimes with the addition of milk or eggs, and baked into not over-thick cakes, which, according to the method of preparation and baking, are known as johnnycake, corn dodger, corn pone, and corn bread. Sometimes, yeast and baking powder are employed. Corn meal is used extensively in the form of hasty pudding, or corn mush, and of Indian pudding. In whatever form used, corn meal is a most nutritious and wholesome food. PLATE IX o V c

'^^ ^^'" '"' f^*'") <'"♦' I"""' '" |"'"t<;idH, fill, uiid miiicr;d iiinflcr lo siifiHfy mIoiic tlio iwa'Ah of tlic Ixtdy, tlic <\c- fi(;ion(ri(!S nrv met by oilier vc^cbihlc! prodiicts, us hc-ins and ju-as, wliiffi are rich in thiisc (lon.stitiK^iits. The form in which ri(!c is Hccn in Ihc household is the icsuit of a polishiiiji; proci^ss wlii(^h removos lh(! reddish cuticle; which the j^ain shows on removal of I Ik; husk'. Wiley's fi^iin;s, r(;pr(',sentin^ the com- position of typical jxdished rice, are as follows : Moistmo 12.40 I'n.lcidH . . . ' 7.50 EtluT extract 0.40 Crude fiber 0.40 Starch, etc 78.80 Ash _ o.r>o 100.00 Rice is the richest of the cereals in starch, and the ))oorest in all other respects. The proteids have not yet been studied systematically. Its starch is very easily digestil^le, and is very useful in all disordered con- ditions of the di<2;estive tract when other solid foods c;annot l)e borne. Under the microscope, the starch granules are .'^een to l)e much like those of corn, but are much smaller and have shaqicr angles. They are separated less easily from one another, and are commonly in groups of variable size. They are shown in Plate IX., Fig. 2. Rice cannot be made into bread, but sometimes is mixed with wlieat flour, in order to give whiteness to the bread. It is used most com- monly in the freshly boiled condition or in the form of ]iuddiugs. The most approved method of cooking it is steaming. This has the advan- tage of not taking away any of the already deficient proteids and salts, which to some extent are extracted in boiling, and also that it leaves the kernels distinct in themselves, and not aggregated in the form of a soggy mush, such as is produced often by improper boiling. Buckwheat. This valuable cereal is used very extensively in this country- as a breakfast food in the form of pancakes eaten hot with syruji or with butter and sugar. As it is devoid of gluten, it cannot be made into bread. The composition of typical American buckwheat is given as follows : Moisture 12.00 Proteids 10.75 Ether extract 2.00 Crude fiber 10.75 Starch, etc 62.75 Ash 1.75 100.00 190 FOODS. The crude fiber is removed veiy largely in the nullint];:, and is almost ■wholly absent from the white flour, a sample of ^vhich, aual}-zed by AVilev, had the following composition : Moisture 11.89 Protoids 8.75 Ethor.oxtract 1.58 Crude fiber 0.52 St;uch, etc 75.41 Ash 1.85 100.00 Buckwheat is the most expensive of the cereals, and consequently is the most sabjeet to adulteration with the cheaper members of the class. The admixture is detected readily by the microscope, since the starch granules have a very characteristic appearance, being small and angu- lar, and of nearly uniform size. Ordinarily they are seen in fairly large masses which are not disintegrated in the process of milling. The starch is shown in Plate X., Fig. 1. (b) LEGUMES. This group comprises peas, beans, and lentils. It is characterized by richness in proteids, which may be present in more than double the amount found in wheat. The chief proteid is legumin, which much resembles casein, and is known commonly as vegetable casein. Accord- ing to E. Fleurent,^ the proteids of this group consist of vegetable casein, composed of legumin and glutenin, and vegetable fibrin, com- posed of albumin and gliadin. Thus : -17- , ,1 ■ f legumin 60.95 Vegetable casein | g,,-^^^j^ 30_g5 T7- i ui cu • f albumin 0.64 Vegetable fibrin | gjj^ji^ 7.76 100.00 Their high content of proteids makes them more satisfying than other vearetable foods, and enables them to act as a fair substitute for animal food. The millions of rice-eaters who, by reason of poverty or religious scruples, are denied the use of animal food, depend upon the legumes to supply the demands of the body for nitrogen. The East Indian, for instance, has no difficulty in satisfying his bodily needs with a hand- ful of beans added to his daily ration of rice. While legumes possess a very high nutritive value, they must be ranked as much more difficult of digestion than the cereals. They require prolonged boiling when cooked whole, but are prepared more quickly and digested more com- pletely when ground into meal and cooked with milk. Even under the most favorable conditions, a large part of the proteids is lost in the excreta. Rubuer has shown that a fifth to a third is not digested and ' Comptes rend us, 1898. PLATE X Buckwheat Starch, x 285. I 4 ;^f%.; Pea Siaieli. 2So. ri'LiS lilCANS. lf)l ;il)S(»rl )('(!, wlicrcuH In flic case of bread the jtrofci*! Iohh \h Ichh than a .S(!V('lll ll. SoiiH! iiidividiials arc oMi^^cd fo forc^f) tlio uho of [xyiH and Iicjiiik, on a<^5()unl, of (laiiilcMcc due In (lie ((»rrnati«)n f>f Hulpliiirclfcd liydr<>^(!n fVoni tli(! siilplmr in I lie Ic^iiiiiin. Tlii.s ol)j(!ly to len- tils, sin(!(' (licy (M)iilain no siilpliiir. Peas, '^riic av('i"a<;'e of (J I analyses of peas, eoMi[)Iled l>y Kidiit^, is as follows : Moisture \\.'.)'.) ProUiida 22.80 Fat 1.79 Cnido (iluT hA^ Htaiv.h, etc 52.:iG Asli _ 2.58 I'OO.OO When dried peas heeonie old, no amount of boilinf^; will make them soft, and they should then be soaked and ei-ushed and cooke^l in some other way. The inuuature pea, so hitrhly prized as a sj)rin^ and summer vegetable, has a very different composition. Five analyses, compiled by Atwater and Bryant,' yielded the following average results : Moisture . ' 74.6 Proteids 7.0 Fat 0.5 Carbohydrates, including fiber 16.9 Ash '. 1.0 100.0 The canned pea appears to coutaiu considerably less nutriment. Of 88 samples reported by the same authorities, none contained less than 77.5 per cent, of water, and some contained as much as 02.7. Their average composition was as follows : Moisture 85.3 Proteids 3.6 Fat 0.2 Carbohydrates 9.8 Ash . ■ Ll 100.0 The starch granules of peas are represented in Plate X., Fig. 2. Beans. There are many varieties of beans belonging to the two large groups, the broad beans and the kidney beans, but their composi- tion is in general quite similar. Forty-one analyses of broad beans ^ Loco citato. 192 FOODS. and 10 of kidney beans compiled by K5uig give the following averages : Broad. Kidney. Moisture 14.7(5 13.74 Pioteids 24.27 23.21 Fat 1.61 2.14 Crude tiber 7.09 8.(>i) Starch, etc 49.01 53.67 Ash _3.26 __3.55 100.(10 100.00 Eleven analyses compiled from American sources by Atwator and Bryant yield averages not materially different. Five analyses of string beans in the fresh state and 29 of canned samples yield the following averages, showing, as in the case of peas, that the canned variety is less nutritious : Fresh. Canned. Moisture 89.2 93.7 Proteids 2.3 1.1 Fat 0.3 0.1 Total carbohydrates 7.4 3.8 Ash 0^8 L3 100.0 100.0 The Soja bean, which has been recommended highly in some quarters as a suitable food for diabetics, is remarkable for its high content of fat, and contains, in addition, so large an amount of starch as to make it quite unsuited to the dietary of the diabetic. Konig has compiled 21 analyses from all sources, and Jenkins and Winton ^ have collected 10 more from American sources. The two groups give the following averages : TfnmV Jenkins ^o^^S- and Winton. Moisture 9.51 10.80 Proteids 33.41 33.98 Fat 17.19 16.85 Crude fiber 4.71 4.79 Starch, etc 29.99 28.89 Ash 5.19 4.69 100.00 100.00 Bean starch is shown in Plate XI., Fig. 1. Lentils. Lentils are the most nutritious of the legumes, but are not a popular food in this country, excepting among certain of the foreign-born population. Their use is, however, on the increase. The averages of 14 analyses compiled by Konig are as follows : 1 Experiment Station Bulletinj No. llj Washington, 1892. PLATE XI Bean Starch. :< 28S. ^'Ur_c Q:fi^; o , cf o. Arrowroot Starch. \ 285. SA(J() AJUiOWROOT. 193 MoiHliire 12M I'n.lcidH 2.'j.70 I<'i.t \.H'.) Oriidi! (lIxM- 3,57 HtiiTch, etc ry.iAQ AhIi _ 3.04 IW.OO 2. Farinaceous Preparations. Under this head ;ir(! iiicliKlcd sa^o, (upioc;!, and arrowroot. SAGO. Sajijo iH dcM'ived from thv, pitli of" IIk; sfciiis of a miiiil)cr of spocioH of ]);ilins, ^V\h) pith is extracted and ground to a |)o\vdcr, wliifli tli(;n is mixed with wtitcr and stniiiied. The stanih j^raiiidcs pass throiip^h with the water, and are deposited as a sediment, which constitutes the sajTO flonr. From the Hour, made into a paste, the various forms of granulated sa<2;;o are preparc^d. Sago is an important starch ))reparation, and sei'vcs as a light and digestihle food for invalids and dyspeptics, but its use is not restricted to these alone. It absorbs the li(piid in which it is cooked, and becomes soft and transparent, but retains its original form. TAPIOCA. Tapioca is derived from a thick fleshy tuberous root called " mani- hot." The starch, which is extracted by a method similar to that em- ployed in the preparation of sago, is heated in a moist state on hot plates and stirred with iron rods, and thus forms irregular masses of transparent granules. lu the process of heating, many of the starch granules become ruptured, and are then partially soluble in cold water. Tapioca, like sago, is useful for both sick and well. ARROWROOT. Arrowroot is a pure form of starch from the tuberous root of the maranta. Its name is derived from the fact that the maranta root is believed to counteract the effects of arrow poison. It is used chiefly as a bland article of food in the sick-room in the form of light pudding or other desserts, but may be combiued with other starch foods and made into bread. There are several varieties, the best of Avhich come from Bermuda and Jamaica. Corn starch is employed frequently as a fair substitute. Arrowroot starch is shown in Plate XL, Fig. 2. 3. Fatty Seeds (Nuts). Nuts are rich in fat and proteids. but contain uo starch. They are of high nutritive value, but on account of their riehuess in fat they are not easily digested, even when reduced to a finely divided state. 13 ' 194 FOODS. ALMONDS. Ill the countries where they are i)rodiieeJ, the almond is eaten both in the oreen and dry conditions. The ripe kernel has a skin, with a bitter tUsagreeable taste. When this is removed by soaking for a time in warm water, the almond is kno^\^l as " blanched." There are two varieties of almond, the sweet and the bitter, both of which contain more than 50 per cent, of oil, about half as much jiro- teid material, gum, sugar, and crude fiber. Both contain enuilsin, a substance which, in the presence of water, acts upon the glucoside amygdalin, present only in the bitter variety, to form hydrocyanic acid, glucose, and benzoic aldehyde. On account of this reaction, the bitter almond is not always safe, and fetal results have occurred from its ingestion. When almonds are baked, they are made more brittle, and are re- duced more easily to a powder. COCOANUTS. The fleshy white kernel of the cocoanut contains about 70 per cent, of fat. The milky interior is chiefly water, but contains nearly 7 per cent, of sugar. WALNUTS. All of the trees of the genus Juglans yield nuts classed as walnuts. The different varieties, though varying in outward appearance and in taste, have practically the same composition. They contain about 60 per cent, of fat, about 16 per cent, of proteids, and about 7 per cent, of sugar and gum. The hazel nut, which belongs to the oak family has about the same composition. PEANUTS. The peanut, known also as ground nut and goober, is less rich in fat, but richer in proteids than other nuts. It contains about 45 per cent, of the former and about 30 per cent, of the latter. CHESTNUTS. The chestnut is not of this class, but for convenience will be con- sidered here rather than with the farinaceous seeds, in which class it properly belongs. It contains but little fet and proteids, about 15 per cent, of sugar, about 25 per cent, of starch, and about 50 per cent, of moisture. It is very indigestible in the raw .state, and even when cooked is very trying to the digestion of those with weak stomachs. It is used very extensively as a food by the French, Spanish, and Ital- ian peasantry in various cooked forms, and largely in the form of bread. VEdETAIlLI': FATS (JlJVJ-: OIL. 19o 4. Vegetable Fats. The vcgctjiblo fiits include! tlu; oils (Ksrivfid fifHii flic relive, ci)ttfjn- sccd, poarnit, and oIJkt Hcc^d.s. Tlicy an; used in the j)n'f)aratir)n (>{ salads and for iiyinj^. Tiie most important are the two first m(;n- tiondd. OLIVE OIL. United States Standard. — Olive; oil is the oil ohtaincd from tlio sound, mature! fruit of tlic (;ul(ivat(,'d (dive; tree (Olca (Mirojucii Jv.j, jinrl subjected to the usual refining processes; is free from rancidity; has a refractive index (25° C.) not less than 1.40()O and not exceeding 1.4680 ; and an iodine mimher not less than 7i) and not exceeding DO. Virgin olive oil is olive oil ohtaincd from the first pressing of carefully selecteti, hand-picked olives. Olive oil is a bland fixed oil derived from the fruit of the many varieties of the olive tree. It is known by various names which desig- nate the grade, but is sold for the most j)art as virgin oil, which is the choicest grade of all and not extensively marke^ted. A'^irgin oil is made from the choicest olives, about three-fourths ripe, whicli are bruised only slightly in the mill, so that only the olive pulp, and not the stone, Ls crushed. The crushed mass is gathered in a heap, and the oil is allowed to drain away without pressure or other influence of any kind. The product has a greenish tint and a far more delicate taste than that made in the manner to be described. In the manufacture of the grades ordinarily seen in the market, the olives, both pulp and stones, are gronnd into an oily paste, which is packed into bags made of woven grass. These are placed in piles and subjected to pressure. As the oil drains away, boiling water is applied to the bags to keep up the flow, and that which is thus obtained con- stitutes the lower grade. Sometimes, the pressed pulp is thrown into water and separated from the broken kernels, which sink to the bottom. The pulp is then gathered up and pressed again. • On account of the cost of pure olive oil, adnltemtion with other cheaper oils is practised very extensively. The principal adulterant is cotton-seed oil, which is exported from this country in large quantities for this and other purposes. J\luch of the oil sold in this country as olive oil is cotton-seed oil put up in the cheapest kinds of bottles, adorned with gandy labels bearing inscriptions often not remarkable for accuracy in the nse of the French language. The author has seen, for example, labels which indicated that the contents of the bottles had been " virginated." Adulteration of olive oil to only a slight extent with the cheaper oils is by no means easy of detection, but %vhen the fraud is fairly ex- tensive it may be sho^^^l by chemical tests and by the use of the re- fractometer, the refractive index of olive oil being less than that of the cheaper substitutes. The iodine number and saponification equiv- 196 FOODS. aleut of olive oil are both less than those of its adulterants. The be- havior of olive oil in contact with nitric acid or with alcolK)lic solution of nitrate of silver is markedly dilfcrcnt from that of the cheaper oils. Thus, equal volumes of strong nitric acid and olive oil, mixed together and agitated in a flask, give a product which has either a greenish tinge or at most one inclining to orange, and no marked change is perceptible on standing for live or ten minutes ; whereas cotton-seed oil similarly treated yields almost immediately a reddish color, >vhich shortly darkens and becomes dark brown or almost black. Again, if 12 cc. of a suspected sample are mixed in a test tube with 5 cc. of a 2.5 per cent, solution of nitrate of silver in 95 per cent, alcohol, and placed in a beaker of boiling water, the resulting change of color gives indications as follows : if olive oil, the color is greenish ; if cotton-seed oil, it becomes black ; if sesame oil, it is dark reddish- brown ; if peanut oil, it is at first reddish brown, then greenish and turbid ; if poppy oil, it is greenish yellow. For further details of chemical tests, the reader is referred to the standard works on the adulteration of foods. COTTON-SEED OIL. United States Standard. — Cotton-seed oil is obtained from the seeds of cotton plants and subjected to the usual refining processes ; is free from rancidity, has a refractive index (25° C.) not less than 1.4700 and not exceeding 1.4725 ; and an iodine number not less than 104 and not exceeding 110. This very important and cheap vegetable fat is a perfectly whole- some and desirable article of food. It is much used under its own name as a substitute for lard and olive oil for frying, and in place of the latter as an ingredient of dressings for salads. It lacks the fine flavor of olive oil, but its substitution in dressings can be detected only by the educated palate. From a hygienic standpoint, there is abso- lutely no objection to its use in the preparation of foods. The same may be said of the orther cheap vegetable oils. 5. Tubers and Roots. In the cooking of tubers, roots, and other vegetables, the albumins and globulins are coagulated, the fibrous matters in the cell walls are softened and ruptured, the starch granules swell and burst, the starch itself becomes somewhat changed in character, and the whole mass is made more digestible. When boiling is the process employed, part of the mineral matter and more or less of the other soluble substances, including certain proteid material, are extracted and lost. POTATOES. The potato is the most important member of this group. It was intro- duced into Spain from Peru about the middle of the sixteenth century, and later, in 1585, into Ireland from Virginia, by Sir Walter Raleigh, PLATE XII Potato Starch, x 285. I'()TAT()FX \[)1 who, in the following y''i"'> iiitn»(lii(;(!(l it uIho into lOn^^liUKl. Prior to that time, mid even later, wluit \v:is known in lOii^rlniirl ;is llic potato Jind the " eonnnon |)o(,uto " iiicnlioncd hy ( icinrd in lii.s Ilcrhul {\i'i\)lj, were sw(!(!t |)ot;iioeH, 'M)ii(-;i(a," iiitrodu(;cd IVom Spain. TIk! av(!r;it;'es of l-'Jd ;ni:ily'^es (Anieriean wunplesj eonijiilcd by Atwater iind liry;int arc iis follows: MoiHtiire 78.3 Proteids ii-ii Fat 0.1 Total carbohydratcH 18.4 Ash 1.0 HK).0 These fi^inxvs dilTcr hiil slin-hlly from the averages of 178 analyses of Knropean sain|)les. The proteids of the potato are (ihielly in the nlliiniiinons jni(Xi be- tween and in the cells. Most of the mineral matter is salts of potas- sium, and this, too, is almost wholly in the juice. The starch was dis- covered by Lenbert and Georgiewsky to be acted upon much more readily by the salivaiy en/ymc than any of the eereid starches. The starch granules are much larger and m(jre irregular in siiape than any of those thus far shown. The hilum and concentric rings are quite distinct. (See Plate XII.) In the process of cooking, the albuminous juice is coagulated and its watery part is absorbed by the starch granules, which swell and con- sequently distend the cells in which they are lodged. The coherence of the cells is reduced, and then they are separated easily into a mealy mass. If the watery part of the juice is not wholly absorbed, the cells are separated with more or less difficidty, the potato remains firm instead of becoming mealy, and is then spoken of as close, waxy, or watery. In this state it is digested much less easily, and may, indeed, be very trying to the stomach. The same condition is noticed in the case of potatoes which have been frozen ; they are very^ watery and of inferior flavor however they are cooked. According to Balland,^ the mealy condition is due not, as supposed, to an especially high content of starch, but to a low percentage of al- bumin, for a potato rich in this substance keeps its shape and neither cracks nor fills apart. He also points out that beneath the skin there are three well-defined layers, which may readily be seen by holding a thin cross-section affiiinst a strono; lio-ht. The outermost is richest in starch and poorest in proteids, but in the innermost these conditions are reversed ; the middle layer represents the mean composition of the whole. The loss which occurs on boiling is much less when the skins are left intact than when removed ; the greatest loss occm's when the potatoes are peeled first and then soaked in cold water. When cooked by steaming, there is no loss whatever. The material lost in boiling ' Journal de Pharmacie et de Cbemie, 1S97, VI. 198 FOODS. a, fiber, pectose, fat, etc. ; 6, non-albuminoid nitro- genous matter: c, albuminoid nitrogenous matter; d, mineral matter. The hatched portion represents the loss. (After Snyder.) has been determined by H. Snyder * as follows : Skins removed, soaked 3 hours : total nitrogen, 46 per cent. ; ash, 45.6 per cent. Skius re- movetl, not soaked : total nitrogen, 16.9 per cent. ; ash, 17.9 per cent. Skins not removed : total ni- FiG. 7. trogen, 1 per cent. ; ash, 3.4 per cent. The composition of the potato and the loss of nutri- ents when boiled with the skin removed are shown by Snyder by a drawing, which is here reproduced. (See Fig. 7.) Potatoes are so deficient in nitrogen that alone they do not constitute a proper ra- tion, but with foods rich in proteids, such as meats, beans, or peas, they are valuable and economical. The juice of the potato contains citric acid and citrates of potassium, sodium, and calcium, which fact accounts for the antiscorbutic value of this vegetable. Attention has often been called to the fact that the potato belongs to a poisonous botanical family, which mcludes belladonna, stramonium, hyoscyamus, and tobacco, all jDowerful narcotic plants ; and it has been pointed out as a paradox that this valuable food possesses no poisonous properties. This, however, is not true, for the potato has been the fre- quent cause of more or less extensive outbreaks of poisoning, and it has long been known that the normal potato contains about .006 j)er cent, of solanin, and that, when sprouting, the solanin content is ma- terially increased. Between 1892 and 1898, many outbreaks of poison- ing occurred in the 15th (German) Army Corps, which were traced by Schmiedeberg and Meyer ^ to solanin in sprouting or completely ripe potatoes. Schmiedeberg's assertion that solanin formation in potatoes is caused by bacteria has been proved by R. Weil,^ who demonstrated that at least two organisms. Bacterium solaiiiferum non-colorabile and Bacterium solaniferum colorabile, have the property of producing solanin from substances normally present. A noteworthy instance of potato-poisoning is that recorded by Pfuhl.* Fifty-six soldiers of a company of the German Army were seized with symptoms of acute gastro-enteritis. The sickness began with chills, fever, headache, colic, vomiting, and diarrhoea. In a number of cases there was collapse, with more or less jaundice. None of the cases ended fatally, nor were there any relapses or sequelae. Investigation showed that the men had eaten sprouting potatoes, a sample of which yielded .038 per cent, of solanin, and that, therefore, those who had eaten their ^ Department of Agriculture, Office of Experiment Stations, Bulletin No. 43, 1897. "^ Archiv fiir experimentelle Pathologie und Phairaakologie, 1895. ' Archiv fiir Hygiene, XXXVIII. (1900), p. 330. * Deutsche medicinische Wochenschrift, 1899, p. 753. HOOTS. vy.) full porlioi) of llu; vc^ctjihlc IijkI iiijjcslcd jilxtiit 0.?, {rnirn of the poi-on, a (|iiiiiiti(ryaiil as follows : Moiwlun^ 09.0 rrotci.ls l.« Fill 0.7 Total carbohydratoH 27.4 Asli 1.1 100.0 Starch constiiutos mueli the f^reatcr part of the earhoiiyd rates ; tho remainder is mainly sn Fiber ''>-^'^^ Ash _Jh^ 100.00 Five analyses compiled by Atwater and Brjant yield averages which are expressed somewhat differently, as follows : Water 77.4 Proteids 1-3 Fat ^ 1.6 Total carbohydrates, including fiber 19.2 Ash 0.5 100.0 When dried in the sun or in ovens, the product is raisins. Those dried in the sun are the better. Raisins are less digestible than grajies, and are not infrequently the cause of derangement of the intestinal canal. What are known commonly as dried ciHTants are raisins made from small seedless grapes. They come from the Levant, and are shipped from Corinth, whence their name in a corrupted form. They are ex- ceedingly indigestible, and are likely to traverse the entire digestive tract without undergoing change. MELONS. The edible portion of melons is very watery, but the small amount of nutriment contained is not nnlikely to cause in many pereons di- gestive disturbances accompanied by annoying eructations. Not many analyses have been recorded. Storer,^ quoted by Konig, has reported three analyses, which give the following averages : ^ Report of Connecticut Experiment Station, 1S79, p. 159. 204 FOODS. Water 88.09 Proteids 0.92 Fat 0.18 Sugar, etc 9.05 Fiber 1.04 Ash 0.72 100.00 Two analy.ses of watermelons noted by Atwater and Bryant give the following averages : Water 92.4 Proteids 0.4 Fat 0.2 Total carbohydiutes, including fiber 6.7 Ash • • . . . . 03 100.0 BANANAS. Bananas and plantains are among the most nutritious of fruits ; in many parts of the tropics, they constitute the chief food of those who are too lazy to perform any kind of manual labor. The edible part yields about 20 per cent, of sugar (cane and invert), about 2 of pro- teids, 0.5 of starch, and rather more of fat. FIGS. The fig in the fresh state is about equal to the banana in nutritive properties. In both the fresh and dried forms, it is esteemed highly as a mild laxative. The dried fig contains about 30 per cent, of water, 50 of sugar, 4 of proteids, and 3 of ash ; the remainder is chiefly seeds and fiber. BERRIES. The various berries are notable for their content of free acids and sugar. Two kinds, the cranberry and the barberry, are too sour to be eaten raw, and must be cooked with sugar in order to be made palata- ble. The composition of the several members of this group is set forth in the following table, compiled from Konig : Water. Sugar. Free acid. Proteids. Fiber, pectin, etc. Ash. Blackberries Cranberries Currants Gooseberries 86.41 89.59 84.77 85.74 78.36 84.71 85.74 87.66 4.44 1.53 6.38 7.03 5.02 9.19 3.86 6.28 1.19 2.34 2.15 1.42 1.66 1.86 1.42 0.93 0.51 0.12 0.51 0.47 0.78 0.36 0.40 1.07 6.97 6.27 5.47 4.92 13.16 3.22 8.10 3.25 0.48 0.15 0.72 0.42 1.02 Mulberries 0.66 0.48 Strawberries 0.81 CANK sua An. 200 9. Edible Fungi. MUSHROOMS. Mush rooms nrc rc|)iilc(l to he cxlrcriicly ridi in nilro^'-cii and other niitricnls, :inurage th(' poor to seek for them in tlu! (ields and woods, in ord(;r to add to the larder. Inasmuch as th(! market ])rie(! of mushrooms for the Uibles of the rich is generally high, and since their food value is de(;idedly over- rated, it would ap|)ear that, where there is a market for them, the f)oor can do much better for their nutrition by disposing of their findings and converting the proceeds into chea[)er, more digestible, more nutri- tious, and less cloying articles of food. Truffles contain more nitrogen than is found in mushrooms, but they arc very nuich more woody, and can hardly be looked upon a.s valuable from the point of view of nutrition. 10. Saccharine Preparations. Sugar was known to the ancient Greeks and Romans, and its manu- flicture has been conducted by the Chinese since the earliest times. It is very sohible and diifusible, and, therefore, is digested easily. Dex- trose is ready for assimilation, but sucrose, maltose, and lactose must undergo first a splitting process within the digestive tract. CANE SUGAR. United States Standard. — Standard sugar is white sugar contain- ing at least 99.5 per cent, of sucrose. Cane sugar is obtained from the sugar cane, sugar beet, sorghum, and sugar maple. It is very soluble in water, but quite insoluble in absolute alcohol. Heated with dilute mineral acids or with citric acid, it splits into dextrose and la^vulose, and then is known as invert sugar from the fact that the polarization becomes inverted. Cane sugar rotates the plane of polarized light to the right ; the two substances into which it is split, dextrose and Irevulose, rotate respectively to the right and left, but the action of l;i?vulose is so much the stronger that the mixture gives left polarization. Heated above 180° C, sugar yields caramel, which is not a simple substance, but a complex mixture of brown products of dehydration. It is used as a coloring for low-grade milk and other articles of food, and somewhat as a flavoring. Cane sugar is sold in various forms : cut or loaf sugar, granulated, and powdered. The cheaper grades, known from their color as " brown 206 FOODS. sugars," contain variable amounts of invert sugar, gummy matters, and other impurities. Sugar is not much subject to adulteration, though there is a popular idea tliat glucose and sand arc common admixtures. It is })robable that sand is as rare an adulterant of sugar as ciialk is of milk. Glu- cose rarely is mixed with sugar, but is used considerably as a sub- stitute tor it in the manufacture of cheap jellies, jams, and candies. Sugars that are somewhat " oflP color " are treated sometimes with ultra- marine in the tinal processes of manufacture. This corrects the fault and makes the product white. Occasionally, the amount added is suffi- cient to cause great alarm in the household when large quantities of sugar are made into syrup with hot water in the prejiaration of preserves and jellies. The blue material comes to the surface as a scum, and its unlooked-for appearance gives rise to suspicion of poison. MAPLE SUGAR. United States Standards for Maple Products. — Maple sugar is the solid product resulting from the evaporation of maple sap, and contains in the water-free substance not less than 0.65 per cent, of maple sugar ash. Maple syrup is syrup made by the evaporation of maple sap or by the solution of maple concrete, and contains not more than 32 per cent, of water and not less than 0.45 per cent, of maple syrup ash. This form of cane sugar is prized highly for its agreeable flavor. It is a much more expensive article than ordinary sugar and is used more as a confection. In the form of syrup, it is used very extensively on buckwheat cakes and with other cereal breakfast foods. It is much subject to adulteration and substitution. A large part of the syrup in the market is wholly artificial, being made of ordinary sugar or glu- cose, appropriately colored, and correctly flavored by means of extract of hickory bark. The sugar itself is imitated in the same way, but one not infrequently sees specimens which are absolutely devoid of any flavor save that of brown sugar. The substitution by flavored cane sugar is easily proved by determining the amount of precipitate of lead malate yielded by 5 grammes of the suspected sample in 10 c.c. of water on the addition of basic lead acetate solution. Five grammes of pure maple sugar so treated should yield, after centrifugation, 2.5 c.c. of precipitate, while pure cane sugar yields none. The presence of glucose is revealed by the behavior of the specimen under polariscopic analysis. GLUCOSE. DEXTROSE. Dextrose, or grape sugar, is inferior in sweetening power to cane sugar, and is not crystallizable to the same extent. It is much less soluble in water, but is soluble in glycerin and in alcohol of ordinary strength. It is found in grapes and in many other fruits and vege- tables, but always associated with Isevidose. By fermentation with yeast, it splits into carbonic acid and alcohol ; in the presence of fer- ments which disorganize proteids, it yields lactic acid. It exerts a strong reducing power on Fehling's solution. MOLASSKS. 207 0()inrru!r(;i;i,l jrlu(!o.s(' i.s ()l)f,;iiii('(l liy lifatinj; nfrin-li, usually (^)ni- Htiiroli, with (liiislasc, or (liliil.c siilpliiiric acid. JicCon; flic final pn^awK of coiicoiitration oC iJic soliilioii, I lie acieer). MOLASSES. United States Standard. — Standard molasses contains not les.s than 25 per cent, of water nor more than 5 per cent, of asli. Molasses is a thick, viscid, dark-coloretl liquid, which drains away in the process of the manufacture of su<^ar. It (;oiitains from fjo to 72 per cent, of su^ar, part of which is sucrose and j)art fruit sugar, vari- ous salts, gummy matters, extractives, and water. It is graded according to color from the cheapest, almost black article known as "black strap," to tlie finest, which is light yellowish brown. When refined, it is brilliant and transparent, and is known as syrup. All grades, but especially the higher, are adulterated extensively with glucose syrup. This reduces the sweetening power, but gives body and a finer appearance. The fraud is detected readily by the use of the polariscopc, since the adulterated article gives a much higher reading, and on inversion, instead of giving left polarization, continues to give a reading to the right almost as high as before. Another, and, from a sanitary point of view, a more important adul- terant of molasses, is the protochloride of tin, known also as " tin crystal " and " salts of tin." This is added for the piu'pose of reducing the amount of color, thus givmg a fictitious added value. It combines with part of the coloring matters, and the resulting compound separates and tends to deposit. Thus a large proportion of the amount added to a hogshead may be found in the " foot," or sugar sediment, which is used quite commonly in the making of cheap candies, such as cocoanut taffy. Only a part, however, is deposited, and hence a s])ecimen thus adulterated will yield notable traces of the salt on incineration and analysis. It is useless to attempt to separate the tin in the ordinary way without previous incineration, since the organic matters present prevent precipitation of the sulphide. Inasmuch as the protochloride of tin is an irritant poison, and since its addition can serve no legiti- mate useful purpose, this form of adulteration should be prohibited and punished. Sometimes tin is present in molasses, not as an adulterant, but because of a practice, followed by some makers of crude sugar, of treating their product with this agent to improve its color before it leaves the centrifugal machines, and thus it finds its way into the by-product. 208 FOODS. HONEY. Honey is classed sometimes as an animal food, since it is a product stored up liv bees, but it can hardly be so considered, since it is obtained from the nectaries of flowers, although during its storage in the bee's crop it undergoes some change. After this alteration by the secretions of the crop, it is disgorged and deposited in the cell of the honey-comb. Honey is a concentrated sohition of sugars, chiefly dextrose and la?vulose, with small amounts of sucrose and mannite, containing also small amounts of wax, organic acids, proteids, mineral matter, pollen, and odorous and other principles. The flavor, color, and odor vary according to the nature of the flowers from which the honey is ol3tained. Sometimes, when derived from poisonous plants, it has toxic prop- erties ; this fact has been noted by both ancient and modern writers. Xenophon, for example, has recorded most serious symptoms of intoxi- cation due to its ingestion, and a number of small outbreaks resembling ptomain-poisoning have been reported by recent writers in this country. Xenophon ' says : " As to other things here, there Avas nothing at w^hich they were surprised ; but the number of beehives was extra- ordinary, and all of the soldiers that ate of the combs lost their senses, vomited, and w^ere affected with purging, and not one of them was able to stand upright ; such as had eaten only a little were like men greatly intoxicated, and such as had eaten much were like madmen, and some like persons at the point of death. They lay upon the ground, in con- sequence, in great numbers, as if there had been a defeat ; and there was general dejection. The next day not one of them was found dead ; and they recovered their senses about the same hour they had lost them on the preceding day ; and on the third and fourth days they got up as if after having taken physic." Dioscorides speaks of a kind of honey that made those that ate it mad, and ascribes its poisonous properties to the great abundance of rose-laurel and other similar poisonous plants. Strabo speaks of honey that made men stupid and melancholy ; and Diodorus, of a certain kind in Colchos which produced such profound weakness in those that ate it " that they appeared for a whole day together like dead men." Honey from the flowers of the yellow jasmine has been known to produce serious and even fatal results, and that derived from a species of rhododendron growing in the neighborhood of the Black Sea has long been recognized as poisonous. The pow^'er of honey to exert a medicinal influence is sometimes turned to good account. Thus, in Abyssinia, where the flowers of the cusso tree are the universal remedy for tapeworm and ascarides, with which a large proportion of the population is afflicted, swarms of bees are kept by order of King Menelek in gardens where no other plant is cultivated, and the honey which they store has been found to have all the good qualities of the drug with none of its unpalatability or un- pleasant effects, such as nausea and vomiting. By microscopic examination, which will show numerous pollen * Anabasis, Book IV., Chap. 8. HONEY. 209 (rriiins, ow v:\n (Icicrrniiu' rnsily (Vom \vli:il, kind nf :i flr)\vf:r lioiKty wuh giiLlierwI. Hon(!y coiilaiiis Jiboiil 7.'> [xt cciiI. (i(" sii^rar. In ^■^•^\\\n^^•(' of the [)rc})«)M(lci';int influ(ii(;t! ui' llic l.'cvulosc on llic I'olaf ion lA' tlic plane of |)(»l;iii/,((l li^lil (lie poljiriscctpc rending of a pure Harnple is jiiniost aJvvays lo llic left ; wIkmi not to the left, {\\v. n-a«linj^ in iK»t more tlian a, few (h^^iccs to llu; li^iit. 'I'lie pcrccnla^c of wjiter avenif^es about IH or 19; occasionally .specimens are foimd to contain as miH'li as 25. llon(^y is an impoilanl sii<;ar food ; it is very ajri-ccaldf to flic taste and easily assimilated. On aecoimt of its (•(»m|)aratively liij^di jiriw, it is very subject to adulteration wilii nlnccsc mid caiic su^^ar. That which is sold in the comb, the comb si ill in its frame, is almost invari- ably }j^enuine. The extracted honeys sold in bottles and tumblers are very commonly mixtures of the frenuine article with glucose or (^ne sugar, and often contain no honey whatever. Jn order to convey the idea of genuineness, it is a common })ractice to insert a small piece of comb. At least one ing(!ni()us fabricator of glucose-honey has been known to add to each tumbler of his product a dciid bee, to serve as a silent false witness of its origin. The detection of adulteration with glucose or cane sugar is an easy matter, since all samples so made give a strong reiiding to the right on polariscopic examination. On inversion of the sample, the right- handed reading persists if the adulterant is glucose, and is changed to the left if cane sugar. It is said that inverted cane sugar sometimes is mixed in proper proportion to make an artificial honey which will give the normal ]iolarisc(>pic test of the genuine article ; and that to imitate th(^ latter still fai'ther, so that microscopical examination also may attest its genuineness, pollen grains are added in sufficient amounts. The ash of such a product alone will reveal the fraud, smce it will contain no phosphoric acid, while genuine honey contains about 0.03 per cent, of that substance. CONFECTIONERY. Candies are preparations made of sugars or substances containing them, such as molasses and honey, with or without the admixture of other food materials, such as nuts, fruits, and chocolate, starches and fats to give body and consistence, and flavoring and coloring agents. The addition of substances which serve no legitimate useful pui-pose, such as terra alba, which is said to be added sometimes to lend weight, and of injurious colors and flavors, may properly be regarded as adulteration ; but the use of glucose sugar, cocoa butter, and other substances of a harmless nature, and possessing value as nutriment, cannot be so regarded. ]Many, some say most, of the cheaper candies, contain variable amounts of glucose and starch, but nothing is to be said against the use of these substances on the score of wholesomeness. The use of terra alba is supposed popularly to be very common, but numerous analvses bv manv chemists throughout the country show 14 ■ * ' 210 FOODS. that this substance is an exceedingly unconiinon ingredient of even the very cheapest candies. The riavoring agents commonly employed are, as a rule, harmless. The colors used, however, are not inlVequontly of a ])()ist)n()us nature, especially in those States which have no laws against food adulteration, or which, having them, make no provision for their enforcement. These injurious coloring agents include the chromates of potassium and lead, tin lakes, and certain of the coal-tar products, such as Martins yellow, diuitrocresol, and diuitroso-resorcinol. The enij)loynK'nt of chronuite of lead and of chromate of potassium is frequently denied, but these substances, nevertheless, are used not uncomnionly, and have been detected bv the author in many specimens of yellow sugars used for decorating cakes, and in yellow candies made in the shape of beans. The majority of the colors used are, however, of a harmless nature. JELLIES AND JAMS. Jellies are semi-solid glutinous preparations made by boiling fruit juices with sugar and allowing to cool ; jams are somewhat similar preparations, which include the pnlp of the fruit as well as the juice. Many of the jellies found in the shops are made with glucose syrup, cane sugar, gelatin, artificial flavorings and colors, and extracts made by boiling the refuse of canning establishments. Jams, likewise, are largely factitious, being made with glucose syrup, flavorings, colorings, various kinds of seeds, and nearly tasteless vegetable tissues, such as summer squash and boiled white turnips. Section 5. BEVERAGES. Stimulant Beverages Containing Alkaloids. These include tea, coflfee, and cocoa, and certain others not nsed to any large extent in this country. The alkoloids of these products are known, res})ectively, as theine and caffeine, which are chemically iden- tical, and theobromine, which is very closely related. TEA. The virtues of tea were discovered, according to Chinese tradition, more than 2700 years before the Christian era. It was used first in England in the seventeenth century (about 1657), and came there into general use about 1675. It was introduced into America in 1731. Tea is the dried leaf of a shrub. Then Chine)is!f<, indigenous to China and other parts of Asia, and cultivated in India, Japan, and Ceylon. Formerly, the varieties of the plant produced by different methods of long cultivation were believed to be distinct species, and were known as T. Jjohea, T. viridis, etc. The differences in the varieties found in commerce depend upon the age of the leaves when gathered and their position on the stem, and upon special methfxls of drying and preparing them for the market. The choicest varieties, for example, are those TEA. 211 wliii'li iiicliidc only ili<' Ictiii iiiiil l(;i\c,-, ;iinl \\\i- [HKirc-t tlio-c iii;i(|c iiji (»(" IJk; l;ifjj;(:sl, uihI coarscsL l(•;lv<■^ Iroin I lie lower end of llic Iwi;:. Titii is cliisscd coiiiiiionly ;is ltccd hv liL'ick. liolli kinds (tuiiH' (roiri IJk^ siiiiic slirni), Liil .irc diirnciil in jioiiil of a;^<', ami ace cured in dil- ler(Mi(j ways. ( J iccn tea i.^ made I'liiin \(iiiii;_r leave-, wliieji are rMires which may he acci^pted an indicalinL: ihe appro.\imat<; (;onstitii- tioii of" u l.\pical s|)<'cinien. KTmii;- has collected Hi analyses, which give tli« following:; averau;es : Moisluiv 11.49 Nilr(.,nTii(ius iiiiinors 21.22 Tlu'ino l-^i'T Volatile (lil 0.H7 Fat, rosin, rtc ;i02 (jfiim, dextrin, I'ti; T.Ki Tannin 12.W Otlicf extractives Ifi.To Fil)er 20.:i0 Asli All lUO.OO But it should be said that the variations in tlie anumnts of individual constituents of these 1<) specimens are very wide: for instance, wat<'r, 4.5!) to Ki.OH ; theine, 0.40 to 4.!)4 ; tannin", 4.10 to 2().-S,S ; fil)er, l-").! 1 to 'io.Ot). Draoendorti' foniul, in 2o specimens, from 1.^30 to .3.01* ]kt cent, of theine, 7.10 to 12.(jG of moisture, and from 24.80 to 44. oO per cent, of total soluble constituents. The ash of pure tea is fairly constant in amount, and almost never reache^s as high as 7 per cent.; usually, between 5 and (> per cent. Tea shoidd be used only in the form of an infusion, made by |X)uring boiling water upon the requisite amount of leaves, and allowing it to stand a short while to " draw." It is used not uncommonly in the form of a tlecoction ; that is, by boiling. This process is objectionable in two ways: first, the delicate aroma is lost by the expulsion of the \ery volatile essential oil ; and second, the leaves are made to yield all their tannin and other extractives, which tend to bring about, sooner or later, derangement of the digestive function and a catarrhal condition of the stomach. The finest and most delicate ]iortion of an infusion is that which is poured oflf within three or four minutes, for in this will be found a maximum of flavor with a minimum of bitterness and astringency. The excellence of an infusion is influenced considerably by the chai'acter of the water, which, if very hard, is slow in exti-actiug the desirable soluble constituents, while, if very soft, it extracts not only these, but far too mpidly the less desirable principles. 212 FOODS. When propi'rly made, tea in mtxleration is a Avholesonie, agreeable, and refreshing stimulant beverage, partieularly grateful in eonditions of mental or j)hysieal weariness. Used in exeess, it exerts a liarmful inlluenee upon the uervous system, and in a too strong form injures the digestive traet and iunetion. The abuse -of tea as a beverage leads, according to Bullard,^ to ring- ing in the ears, tremor, uervousuess, headache, neuralgia, hysteria, irregularity of the heart, dyspno'a, dyspepsia, and consti[)atiou. Dr. Hayes, the Arctic explorer, has testified to the value of tea and coffee in enabling men to endure cold and hardship of all sorts, tea being especially soothing at the end of a hard day's work. ^Miile tea by itself can hardly be looked upon as an article afford- ing any important amount of nutriment, as conunonly consumed it serves as a vehicle for other substances, as sugar, milk, and cream, having high nutritive value. Adulteration of Tea. — It is commonly stated and generally be- lieved that tea is adulterated extensively with other kinds of leaves, including those of the beech, sloe, willow, and hawthorn ; but at the present time, it is extremely improbable that such adulterants ever are mixed with tea known to be intended for export to this country. Whatever the conditions may have been prior to the enactment of the national law governing tea importation, the fact noAV is that our tea supply is practically free from this form of adulteration. The detec- tion of spurious tea leaves would be an easy matter, since the genuine have a very characteristic appearance which can hardly be confused \yii\i that of any of the possible substitutes ; and even when broken into small bits, the characteristic differences in venation and serration, and in the stomata as well, are plainly discernible. More probable forms of adulteration include the admixture of wholly or partially exhausted leaves ; the addition of astringent mat- ters, such as catechu, to lend color and apparent strength to the infusion ; the presence of foreign mineral matter ; and the practice of " facing." The presence of any large proportion of exhausted leaves can be detected by the low amount of total soluble extract and by the small amount of soluble ash, which should not be less than 3 per cent, of the weight of the leaves. The presence of important amounts of accidental or added mineral matters is shown in the total ash, which in a genuine specimen rarely amounts to 7 and never to 8 per cent. The substances most often found are sand and soapstone ; the first named is found some- times in amounts exceeding 25 per cent. Catechu is applied occasionally to exhausted tea leaves with the aid of solutions of gummy matters, for the purpose of adding astringency and color to the infusion. Teas so treated have but little, if any, of the true aroma, and their infusions yield a sediment in which the par- ticles of catechu can readily be seen. The object of " facing " is to make the product appear to be of greater value, and the practice is, therefore, properly speaking, one which comes within the definition of fraudulent adulteration. Damaged 1 Boston Medical and Surgical Journal, April 8, 1886, and September 8, 1887. or otliorwlno Inrfirior 1c (IcIcciIxmI hy tlie nso of" tin; inicroscojx! and hy clicniic^il analyHlH. COFFEE. (\)ire(> is tlio seeds oCllie ( 'nU'ca Anthira, dried an"il|>y hei-ry e<»iil;iinin;r, nsnally, two seeds. The tree is said to liasc oriLiinated in AhysHinia, where, liowever, in tlu; seventeenlli ceiilnry there weic few, \[' any, H[)ecimens, and to have been introdn(;('d into Arabia in the lil'teenth centnry. It is now j>^rown very extensively in l>ra/.il, -lava, I'ern, Ceylon, West Indies, and other hot (;onntries. 'Hie first Kuropean (o mention it was Prosper Alpinns, of Pachia, who inchided il in ;in neconnt of" K^ptian })lants, pnblished in 151)2. 'i'he first work devoted wholly to eoffce was a small Latin treatise, he sdhihcrrliiK/ potlniie calnir, by Fanstus Nairo, Rome, 1671. Coflee was lirst sold in I^ondon by a Levantine, in 1650, and some years afterward was introduced into France. The first whole cargo introduced into this country arrived in 1809, but coffee houses were licensed in Massachusetts as early as 1715. The world's jn-oduction of eolfee for the year ended June 30, 1000, was estimated at almost 000,000 tons.' This country alone consumes more than the whole of Europe: in 1897 we consumed 31 H, 170 tons against 305,150. The total consumption In" Germany was 136,390; by France, 77,310; by England, 12,420; and by Italy, 12,500 tons. 7Vs is the case with tea, coffee must undergo a process of rf)astiug before it is fit for use, although it is said that the Arabians and other Eastern peoples make a decoction of the raw article and swallow the grounds as well as the liquid. The roasting is conducted at about 200° C. until the natural color, which is greenish, grayish, or drab, is changed to a rich dark brown. During the process, certain volatile aromatic principles are developed, the alkaloid caffeine is dissociated from its union with tannin, the moisture is very largely expelled, the sugar is caramelized, gases are formed (largely carl^onic dioxide) which cause the berry to swell, and much ru]ituring of the cell layers occui's. The berry thus loses in weight and gains in bulk. The process must be conducted carefully, else the quality will not be what is desired, since if the roasting is not pushed sufficiently far, there Avill be insufficient development of aroma ; and if it is carried too far, the volatile matters are expelled and the ]iroduct acquires an unpleasant taste. On account of the volatile nature of the aromatic principles developed, coffee should be roasted only as the demands of commerce make it necessary-. On long keeping, except in hermetically sealed containers, it undergoes extensive deterioration. For the same reason, the roasted berries should be ground only as needed. 1 Consular Reports, Vol. LX.. p. 258. -1-t FOODS. Coffee contains less caifeine (tbeiue) than is found in tea ; thus, Prag- endorff found the amount in 25 samples to vary between 0.G4 and 2.21 j>er cent., A\hereas in about the same number (23) of samples of tea, the range was 1.36 to 3.09. It contains consiilerable amounts of fat, generally over 12 per cent., about the same amount of nitrogenous matters, small, quite unimportaut amounts of sugars, gununy matters, and other substances, and about 40 per cent, of fiber. Coffee is used in infusion and as a decoction. Like tea, it loses its ]>leasant aroma when boiled, but its decoction is less bitter and astrin- gent than that of tea. In order to enjoy both the fragrance of an in- fusion and the strength and body of a decoction, it is not an uncommon practice to make first the one and ])our it off^ and then, with a fresh portion of water, to boil the grounds for a few minutes, and then to mix the two liquids together. Coifee acts as a decided stimulant to the nervous system, enables one better to perform arduous work, and diminishes the sense of fatigue. In small amounts, it increases the force and frequency of the pulse, but taken in excessive quantities, it causes palpitation and intermission, besides general nervousness and derangement of digestion. It has a marked inhibitory influence on gastric digestion, and is more opjiressive to the stomach than tea and, hence, should be used with caution by dys- pc])tic^^. A^^ith some persons it stimulates peristalsis, and tlius acts as a gentle cathartic. It increases the secretions of the skin and kidneys. Coifee is adulterated very extensively with a variety of substances of widely diiferent nature, including chicory, dandelion, and other roots, roasted cereals and legumes, sawdust, date stones, red slate, acorns, and other chea]i articles. It is not alone in the ground form that it is falsified, for even the beans are miitated with mixtures of flour and other materials, moulded to the correct shape and carefully roasted and colored. The detection of adulterants in coffee requires but little time. Of great assistance is the fact that coffee conttiins absolutely no starch, v\^hile most of the commoner adulterants contain it in abundance. Therefore, if a specimen under examination is boiled and filtered, and the filtrate gives a dirty blue reaction with test-solution of iodine, one may l)e sure that adulteration has been practised. But not all of the adulterants are starchy in their nature and, therefore, other examination is necessary. Microscopical examination will detect not only the starchy, but the non-starchy matters as well. Under the microscope, ground coffee has a characteristic appearance which cannot be mistaken for any- thing else. Chicory and other roots, date stones, and all other berries and seeds have their own characteristics. For the mere determination of the question of purity, only a knowledge of the microscopical ap- pearance of coffee itself is required, and this is acquired easily and quickly by direct study. For the identification of the adulterants present, one necessarily should be familiar with the appearance of all of the substances used. Chicory is the root of the CicJiormm intybus, a perennial herb, grow- COCOA. 21; iii^ wiM .•111(1 cxlciisivclv ciill i\;ilii| ill till r'(.iiiitr-y ;iiiil in lMirlaced helwcen the tctlli. The par- ticles of cotT'eo are much harder than those; ofehi('ory, which yield very readily to pressure and also hav(! a sweetish taste. Interior and damaged raw cod'ees not ini"re(pieiitly are colored and faced, in order that they may be improved in ajijjearanee or be made to imitate better grades. The facing agents used are mixtures contain- ing variable amounts of ultramarine, indigo, clay, gyp.snm, cliromate of lead, and coal dust. According to (1. Wirtz,' inferior grades of cotfee are treated largely at Antwerp, Rotterdam, Hamburg, J^remen, and elsewhere, by washing, coloring, and tiually drying by centrifugation \\\\\\ sawdust, the result being a line wdiite product of an apparently greater value. Package coifees sold under various names, such as " I'^rench Break- fast Coffee," "Vienna (\)ine," and "Eureka Breakfast Coffee," are rarely anything more than roasted and ground cereids and peas. It is to be said, however, that their character usually is indicateical America. It is estimated that the annual production of the .seeds amounts to about 150,000,000 pounds, more than a fifth of which is 1 Zeitschrift fiir I'ntei-suchung dor Nahniners- nnd Geniissmittel, 1S9S, p. 248. - Quoted by Leiieh, Food Inspection and Analysis, p. 391. 216 FOODS. exported by Ecuador alone. Nearly a tiftli of the annual crop is con- sumed M-itbin the United States. Tiie fruit of the cocoa tree is a pod, about a foot long and half as wide, filled -with " beans," or " chocolate nuts," about as large as almonds, imbedded in five rows of from four to ten each in a pulpy matrix. \Mien ripe, the |)ods are gathered and collected into heaps, ■and left for a day or longer ; then they are cut open and deprived of the seeds, which are allowed to undergo a process of fermentation in earthen vessels or in holes in the ground. This process, which must be regulated very carefully, has for its object the removal of an acrid, bitter taste and consequent improvement in flavor. Sometimes, the seeds are dried in the sun as soon as removed, but the product is then of much less value ; sometimes, the entire pod is buried until the pulp becomes rotten and softened. AVhen the fermentation process is com- pleted, the seeds are dried carefully in the sun, and then become hard, brittle, and reddish or reddish brown in color. In the preparation of cocoa for the market, the seeds first are cleaned and carefully roasted. As is the case with coffee, the roasting must be carried to a certain point to insure the development of the desired flavor, but not so far beyond as to impair it. During this process, the thin husks of the seeds become more detachable, and before the next operation they are removed. Then the seeds are crushed lightly and freed from their hardened germs, and in this form are known as " nibs." These are ground in a special form of mill into a paste (" flake cocoa"), which is moulded into cakes and allowed to harden. In this form, the product is known as plain chocolate. The sweet and flavored choco- lates 'are made with the addition of sugar, vanilla beans, cinnamon and other spices. Inferior vanilla chocolate is made with artificial vanillin and coumarin, in place of the far more expensive and better flavored vanilla bean. For the preparation of powdered cocoa, it is necessary to remove a part of the oil, which, when present in its normal amount, favors cak- ing. This removal is accomplished by hydraulic pressure, and the paste is then passed through sieves of exceedingly fine mesh. The so-called soluble cocoas are prepared with sugar and starches, particularly arrowroot, but the cocoa itself is not soluble in water. The apparent solubility is due to the fineness of the powder and to the in- crease in the specific gravity of the liquid due to the sugar in solution, both these conditions favoring prolonged suspension without sedimen- tation. Some of the Dutch soluble cocoas are treated with alkalies, for the removal of the crude fiber and for their effect upon the coloring matters. These cocoas thereby lose part of their natural flavor, but the loss is made up somewhat by the addition of fragrant foreign matter. Cocoa Avas introduced into Europe by the Spaniards after their in- vasion of Mexico under Cortez, in 1519. It was not known in England until 1657, when it was sold first in London by a Frenchman. In this country, it first was prepared and sold at Danvers, Massachusetts, in 1771, from raw material brought from the West Indies by the fisher- men of Gloucester. BEER. 217 Uiiliki! tea and cofrcc, wliidi in llicmHolvoH can hardly 1m; regarded •AH jiddiiiji; Jiiiy nut ritriciil- lo the did, cocon is :iii fxcccdiii^dy valiinliN; food, vvliich |K»Mscss('S I lie adv:inla;i;c oC iiiiK'li mil : iinciil in y-ni:ill ImlU, and licdcc is |):ir(i(Mii;irly suilcd to the ndcds of tlio.s(! cn^^a^^cd in CXiKKlilions rcin(»\<'nddin;rs, :ind oflicr eorn|)onn(' hrcwiii^'- uilli tliciii. Ill l(i2!>, III*' cull i\;il ion nC hops li;id liccii c;inicd (III Inr .-oiiic lime ill New A inslcrdiini, :ind Imp rools were xnl liir (Vdiii lOn^^land hy fiur aiidiorilics of MassaclniscKs. In iic;irl\- ;dl llic colonics, tlic hrcwirif; (>(' 1)('(M' vva,M i'ct;'ai'dcd as (piilc as csscntiMJ ;iii ;iccMiiipli-|iiiicnt of women as ilic ahililv (<» make ^ood l)reae|| win<> or spirits willioiil a pciinll, hiit made no rcrcrence lo licer. In t\u\ I'ollowiiii;' year, il was or(jei-cd llial no one -lioiild clinr^n- more than a, pciin\' for a (piail of liccr, and in Id.".?, llial no iiin-kecpcr or vi(;- lualler should sell am' inloxical ini;' drink lail Im'ci- ; ;iiid lhi> the\- were jn'ohihitcd iVom hrewinii; ihcmsclves, hut must oWtaiii from a licensed bi'cwcr. In (lie ioUowino- ycai', owin;^- to the I'act tliat the only one of this ckiss was nnahk' to meet the demand, they were allowed t(» eondnct the proeess themselves. In KM!), it was ordered further that every inn-keeper and victualler should keep always on hand a su|)ply ot" !L''ood, wholesome beer. In 1()51, the court undertook to stimulate the |>rf>- duetion of a better o:rade of beer in the belief that thereby the growing tendency to the use of wine and spirits and the increasing habit of drunkenness would he cheeked, and permission was granted to charge one, two, and tlu-ee pence per qnart, according to the amount of malt used ])er barrel. A duty of a shilling p(M' bushel of imported malt, imposed in 1()-j4, called forth a ]>rotest I'rom Boston merchants, on account of the veiy greiit importance of beer as a beverage of the people. In the following yejir, in order to promote home prodnction of malt, importation was ])rohibited, bnt this order was repealed in 1()()0. In 1(367, the use of molasses as an adulterant of beer was ])unishable by a fine of five pounds. Similar laws relating to beer were passed from time to time by the authorities of all the original colonies. Process of Manufacture of Beer. — The first step in the brewing of beer is the preparation of the malt. The barley iirst is steejxn^l in water for several days, and then is removed and arranged in heaps, which, after a time, are spread ont and turned repeatedly nntil germi- nation has })roceeded to the requisite extent. Xext it is drietl in kilns at a temperature below or about 90° F., and then is heated to from 125° to 180°, according to the color desired. This process develops flavor, completely checks germination, and determines the commercial character of the product. The steeping of the malt is done best in water containing ci>nsiderable <^f the minci-al salts that cause hardness ; a soft water exerts too much solvent action on the 220 FOODS. proteid matters, which, soon after extraction, are likely to undergo deoompositioii. Duvino- the j^rogress of o-eriuinntion, the ferment diastase is develojied, and ]>roeeeds to convert the starch into dextrin and maltose. After the g-erms and rootlets have been removed by proper screening and sifting, the malt is crushed, and then an infusiou, the "wort," js made with Avater at about 160° F. This is drawu oif from the exhausted malt, aud then boiled for an hour or two with hops, which, besides giving a eliaracteristic l)itter flavor, assist in claritication by the action of their contained tannin on some of the proteid matters. Then the boiled bitter wort is cooled rapidly, run into vats, mixed with yeast, and allowed to ferment for several days, during which time alcohol and carbonic acid are formed fi'om the maltose. The nature of the product is influenced very largely by the purity of the yeast and by the method of fermentation followed. Top fermentation is carried on rapidly, and at a comparatively high temperature, the yeast growing at the surface ; in bottom, or sedimentary, fermentation, the veast grows at the bottom, tiie process is slower, and is carried on at a lower temperature. The chief advantage of the employment of yeast which grows at a low temperature is that other, perhaps undesirable, growths may be unable to proceed. Whatever the process of fermenta- tion followed, not all the sugar should be allowed to be converted, for then the flavor would be not what it should, and the kee])ing qualities would be impaired. On the completion of fermentation, the beer is separated from the yeast and transferred to vats, where it is clarified. As clarifying agents, a variety of materials are used, the chief of which are chips or shavings of certain woods, as hazel or beech, which attract and hold the particles which cause turbidity. These materials affect in no way the taste of the beer. Other substances used include gelatin, isinglass, flax-seed, and carrageen. After clarification is accomplished, the product is stored for a time in storage casks, where it undergoes a further slow fermentation at a low temperature, after which it is ready for use. Substitutes for Barley Malt. — While barley is recognized univer- sally as the grain best suited to the brewing of wholesome beer, any other cereal may be used. Sometimes, unmalted grains are added to the malt before the infusion is made, for the diastase of the malt is capable of converting not only the starch with which it naturally is associated, but a large amount of other starches ; and so, rice, corn, and other cereals may be employed. Glucose and cane sugar are used somewhat, but the product is decidedly inferior in quality, since these substances are lacking in some of the elements, as proteids and min- eral matters, which contribute to the desirable character of the best beers. Concerning the use of glucose, which adds strength to the wort, there can l)e no objection on the score of being in any way deleterious to health. The popular belief in the unwholesomeness of glucose made from corn starch led the U. S. Treasury Department, in 1882, to request an investigation of the subject by the National Academy of Sciences. This was conducted by a committee of eminent scientists, liPJEll. 221 inclulvhich the sugars were made. Between Xo- vember 25, 1900, and January 10, 1901, there were no less than 36 deaths iu Manchester alone, which were attributed to arsenic^il poison- ing. The symptoms observed iu this extensive outbreak began, as a rule, with disturbances of digestion, followed soon by laryngeal and bronchial catarrh and acute skin eruptions, and then by disturbances of sensibility and motor paralysis. The cases were grouped into those iu which all the above symptoms were fairly well marked, and those in which the principal lesions were, respectively, of the skin, heart, and liver, and paralytic. Substitutes for Hops. — Various substances have from time to time been reported as being used in place of hops to give bitterness to beer. These include nearly everything having a bitter taste, such as strych- nine, chirata, calumba, cocculus indicus, aloes, and picric acid. Cocculus indieus was mentioned in Holland as early as 1620 as an adulterant. This and its active principle picrotcvxine, and picric acid, have been employed occasionally in England and elsewhere ; but at the present time, it is safe to say, none of these substances is used. Of 476 sam- 1 British Medical Journal, Nov. 24, 1900. 222 FOODS. pies of beer examined for the State Board of Health of New York, in 1885, not one was found to contain any \\o\) su])stitutos whatever. No ohjootions can be alloii'ed a^-ainst such wliolcsomc bitters as (juassia, gentian, caluniba, and chirata. Evidence that they ever are em])loyed is exceedingly slight. As a matter of fact, there is no satisfactory sub- stitute for hops, which give not alone bitterness, but other flavors and g, ])eculiar aroma, due to the resinous matter which they contain. Tn the sixteenth and seventeenth centuries, various other flavorings \Ncrc used, suc'h as sage, eoriaudcr, laurel leaves, i)epj)cr, grains of I'ai'adise, orris, and essential oils. Physical Properties and Chemical Composition of Beer. — Beer should be {)ert'cctly clear and bright. The presence of any turbidity denotes either imj)crfect bre^\■ing or the t)ccurrence oi' undesirable decomposition processes. The latter are accompanied generally by dis- agi'eeable odors. The taste should be pleasantly bitter and inclining to sweetness rather than to acidity. There should be a sufficient amount of carbonic acid to make a pleasant im])ression in the mouth, such as is not produced by flat beer. The specific gravity ranges from about 1.005 to 1.025, averaging below 1.020. In bock beer, which is a special brew containing a considerable increase in malt extractives, the specific gravity is notably higher, running as high as 1.035, and averaging more than 1.021. The most important constituents of beer are the extract and alcohol. The extract includes all of the non-volatile matters in solution, and consists of proteid matters, dextrin, sugar, hop resin, and other sid)- stances left as a residue on complete evaporation. The amount is vari- able ; it is highest in porter, stout, and bock beer, and lowest in the light-colored lager beers. In the former, it averages about 7.50, and in the latter, about 5.50 per cent. Twenty-eight specimens of Amer- ican beers, ales, and porter collected in Washington, and analyzed by ]Mr. C A. Crampton,' averaged 5.53 per cent. The average extract of 182 analyses of specimens of beers of the lighter kinds, compiled by Konig, is stated at 5.49 (range, 1.98-9.23); of 211 lager beers of all kinds, at 5.78 ; of 50 export beers, at 6.48 ; and of 5() bock beers, at 7.20. The amount of alcohol is also variable. The specimens examined by Crampton, averaged 4.63 per cent, by weight ajul 5.79 by volume. The light beers above mentioned (Konig) averaged 3.46 per cent, by weight ; the second group, 3.95 ; the third, 4.31 ; and the fourth, 4.74. Adulteration of Beer. — Beer is su})posed pojudarly to be exten- sively adulterated, and the substances alleged to Ijc in common use make up a list remarkable for length and variety, including such poi- sonous drugs as opium, belladonna, henbane, and strychnine, many of the aromatics and aromatic bitters, corrosive acids, di-astic cathartics, and many other sul>stances. The actual adulteration of beer, however, is restricted practically to the use of preservatives, such as sodium fluoride and salicylic acid, of sodium bicarbonate to correct acidity ^ U. S. Department of Agriculture, Division of Cheuiistry, Bulletin 13, p. 282. ANAi,ysi,s o/<' /;/';/';/;. 2L'.'i and to iiU!rcaH(i the " Ix'atI," mikI of .silt In coi-i-icl IckI t;i:-tf .-hkI Id iiis|)irc lliifsl- ("or inoi-c. 'riic use of |)i( >(i'\:iti\('s is iIk' oiiI\' Uinn oC ;i(liill(i;il ion wliich Ik <»r pPMclicMl li}<;'i('iiic in: [kiiImikc, ,iii(| in scvcr';il count ri<''^ i^ |irini.-li- jiblo l)y liciiNV |K ii;ii(ic.-. In eess of reasoning;, one nii^^lit contend jii^t as well thaiopiiMu in food and drink would pre\ciil |»ain, and liiniodide oi' mercury keep the sysl('ni fvrv. from sypliililie infeclion. Analysis of Beer. In tlio analysis of heor, tlie most inipoi'tant pr(»c(!sses arc tlic deter- mination of tlio percentanx! of aI(;oliol and of extract, and the detection ol" preservatives. Determination of Alcohol. — ^i'^or the determination of the jK-reent- a_i;c of aU'ohol, a suHieiently lars;'e |)oi'tion of heer should he shaken in a, capacious flask until the carl)oni) Determination by Open Evaporation. — ddiis jncthod involves le,«s manipulation and gives e([ually accurate results. The specitic gravity of the beer is determined first in the manner above mentioned. Then place 100 cc. at (50° F. in a glass or ]iorcelain evaporating dish, and by the application of heat drive off rather more than half the amoinit. Remove, cool, make up with water to the original volume at 60° F., and again dotermiue the specitic gravity. Pivide the original gravity by the latter, and the result C(pials that of the alcohol which has been expelled. Refer to the table, ;ind obtain therefrom the percentage of alcohol in the beer. The following table, by J\lr. Fdgar Richards, is the one used l)y the Association of Official Agricultural Chemists:' ^ U. S. Departiuent of Agrioiiltnro. Division of Chemistry, Bulletin Xo. 46, Wash- ington, Government Printing Oflicc, lSi)9. 224 FOODS. TABLES SHOWING PERCENTAGE OF ALCOHOL BY WEIGHT AND BY VOLUME. {Recalcutaied from the determinations of Gilpin, Drinkwater, and Squibb, by E\l(/ar Richards.) Specific Per.cent. Per cent. Specific Per cent. Per cent. Specific Per cent. Per cent. gravity at alcohol by alcohol by gravity at alcohol by alcohol by gravity at alcohol by alcohol by 6U° F. volume. weight. volume. weight. 60° F. volume. weight. LOOOOO 0.00 0.00 0.99629 2.50 1.99 0.99281 5.00 4.00 0.99992 .05 .04 622 .55 2.03 274 .05 .04 984 .10 .08 615 .60 .07 268 .10 .08 976 .15 .12 607 .65 .11 261 .15 .12 968 .20 .16 600 .70 .15 255 .20 .16 961 .25 .20 593 .75 .19 248 .25 .20 953 .30 .24 586 .80 .23 241 .30 .24 945 .35 .28 579 .85 .27 235 .35 .28 937 .40 .32 571 .90 .31 228 .40 .32 930 .45 .36 564 .95 .35 222 .45 .36 .99923 0.50 0.40 .99557 3.00 2.39 .99215 5.50 4.40 915 .55 .44 550 .05 .43 208 .55 .44 907 .60 .48 543 .10 .47 202 .60 .48 900 .65 .52 536 .15 .51 195 .65 .52 892 .70 .56 529 .20 .55 189 .70 .56 884 .75 .60 522 .25 .59 182 .75 .60 877 .80 .64 515 .30 .64 175 .80 .64 869 .85 .67 508 .35 .68 169 .85 .68 861 .90 .71 501 .40 .72 162 .90 .72 854 .95 .75 494 .45 .76 156 .95 .76 .99849 1.00 0.79 .99487 3.50 2.80 .99149 6.00 4.80 842 .05 .83 480 .55 .84 143 .05 .84 834 .10 .87 473 .60 .88 136 .10 .88 827 .15 .91 466 .65 .92 130 .15 .92 819 .20 .95 459 .70 .96 123 .20 .96 812 .25 .99 452 .75 3.00 117 .25 5.00 805 .30 1.03 445 .80 .04 111 .30 .05 797 .35 .07 438 .85 .08 104 .35 .09 790 .40 .11 431 .90 .12 098 .40 .13 782 .45 .15 424 .95 .16 091 .45 .17 .99775 1.50 1.19 .99417 4.00 3.20 .99085 6.50 5.21 768 .55 .23 410 .05 .24 079 .55 .25 760 .60 .27 403 .10 .28 072 .60 .29 753 .65 .31 397 .15 .32 066 .65 .33 745 .70 .35 390 .20 .36 059 .70 .37 738 .75 .39 383 .25 .40 053 .75 .41 731 .80 .43 376 .30 .44 047 .80 .45 723 .85 .47 369 .35 .48 040 .85 .49 716 .90 .51 363 .40 .52 034 .90 .53 708 .95 .55 356 .45 .56 027 .95 .57 59701 2.00 1.59 .99349 4.50 3.60 .99021 7.00 5.61 694 .05 .63 342 .55 .64 015 .05 .65 687 .10 .67 335 .60 .68 009 .10 .69 679 .15 .71 329 .65 .72 002 .15 .73 672 .20 .75 322 .70 .76 .98996 .20 .77 665 .25 .79 315 .75 .80 990 .25 .81 658 .30 .83 308 .80 .84 984 .30 .86 651 .35 .87 301 .85 .88 978 .35 .90 643 .40 .91 295 .90 .92 971 .40 .94 636 .45 .95 288 .95 .96 965 .45 .98 ANALYSIS OF liKFIi. 220 SrH!Clfl<' I'or (;(!n(,. IN^rrtciit.. ."^liiicilic I'crriTit. I'er tout. Hp«cinl liy VOlllllHi. 7.50 weight.. 1 6.02 volume. weight. VOlllUiC. w«;lKlit. 0.9895!) 0.98603 10.50 8.46 13,60 10.90 95:5 .55 .0(1 597 .55 .49 267 ,65 .94 9^7 .(iO .10 5i)2 .60 ,53 262 .60 .98 9K) .(;5 .14 586 .65 .57 256 .65 11.02 9:m .70 ,18 580 .70 ,61 251 .70 .00 928 .75 .22 575 .75 ,65 246 .75 .11 922 .80 .26 569 .80 ,70 240 ,80 ,16 91 G .85 .30 663 .86 .74 235 .86 ,19 909 .90 .:;i 557 .90 .78 230 .90 Xi 903 .95 .38 552 ,95 .82 224 .96 .27 .98897 8.00 6.42 .98546 11.00 8.86 ,98219 14.00 11.31 891 .05 .40 540 ,05 .90 214 .06 .36 885 .10 .50 535 ,10 .94 200 .10 .39 879 .15 .54 529 .15 ,98 203 .16 .43 878 .20 .58 524 ,20 9.02 198 ,20 .47 8(57 .25 .62 518 .25 ,07 1 193 .26 .62 861 .30 .67 513 .30 ,11 ! 188 .30 ,66 855 .35 .71 507 ..35 ,15 182 .36 ,60 849 .40 .75 502 .40 ,19 177 .40 .64 843 .45 .79 496 .45 ,23 172 .45 .68 .98837 8.50 6.83 .98-191 11.50 9.27 ,98107 14.60 11.72 831 .55 ,87 485 .55 ,31 161 .55 .76 825 .60 .91 479 .60 ,35 156 .60 .80 819 .65 .95 474 .65 ,39 151 .65 .84 813 .70 .99 468 .70 ,43 146 .70 ,88 807 .75 7.03 463 .75 .47 140 ,75 ,93 801 .80 .07 457 .80 .51 135 ,80 .97 795 .85 .11 452 .85 ,55 1 130 .85 12,01 789 .90 .15 446 .90 ,59 125 .90 .05 783 .95 .19 441 .95 ,63 119 ,95 ,09 ,98777 9.00 7.23 .98435 12.00 9.67 .98114 15,00 12.13 771 .05 .27 430 .05 .71 108 .05 .17 765 .10 .31 424 .10 .76 104 .10 .21 759 .15 .35 419 .15 ,79 099 .15 .26 754 .20 .39 413 ,20 ,83 093 .20 .29 748 .25 .43 408 .25 .87 088 .25 .33 742 .30 .48 402 .30 ,92 083 ..30 .38 736 .35 .52 397 .35 ,96 078 .35 .42 730 .40 .56 391 ,40 10.00 073 .40 .46 724 .45 .60 386 ,45 .04 068 .45 .60 .98719 9.50 7.64 .98381 12.50 10.08 .98063 15.50 12.54 713 .55 .68 375 .55 ,12 057 .55 .58 707 .60 .72 370 .60 ,16 052 ,60 ,62 701 .65 .76 364 .65 ,20 047 ,65 ,66 695 .70 .80 359 .70 .24 042 ,70 .70 689 .75 .84 353 .75 .28 037 ,75 ,75 683 .80 .88 348 .80 ,33 932 .80 ,79 678 .85 .92 342 .85 ,37 026 .85 .83 672 .90 .96 337 .90 .41 021 .90 .87 666 .95 8.00 331 ,95 ,45 016 .95 .91 .98660 10.00 8.04 .98326 13.00 10.49 ,98011 16.00 12.95 654 .05 .08 321 .05 .53 005 .05 .99 649 .10 .12 315 .10 .57 001 .10 13.03 643 .15 .16 310 .15 ,61 97996 ,15 .08 637 .20 .20 305 .20 ,65 991 1 ,20 .12 632 .25 .24 299 .25 .69 986 .25 .16 626 .30 .29 294 .30 .74 1 980 .30 .20 620 .35 .33 289 .35 .78 975 .35 .24 614 .40 .37 283 ,40 .82 970 .40 .29 609 .45 .41 278 .45 .86 965 .45 ..33 15 226 FOODS. Specific Per cent. Per cent. Specific Per cent. I'cr cent. I Specific Per cent. Per cent. gravity at alcohol by alcohol by gravity at alcoliol by alcoliol by gravity at alcohol by alcohol by 60° F. ! volume. weight. 00° F. volinne." weight. GU° F. volume. weight- 0.97960 16.50 13.37 0.97658 19.50 15.84 0.97355 22.50 18.34 955 .55 .41 653 .55 .88 350 .55 .38 950 .60 .45 648 .60 .93 345 .60 .42 945 .65 .49 643 .05 .97 340 .65 .47 940 .70 .53 638 .70 16.01 335 .70 .51 935 .75 .57 633 .75 .05 330 .75 .55 929 .80 .62 628 .80 .09 324 .80 .59 924 .85 .66 623 .85 .14 319 .85 .63 919 .90 .70 618 .90 .18 314 .90 .68 914 .95 .74 613 .95 .22 309 .95 .72 .97909 17.00 13.78 .97608 20.00 16.26 .97304 23.00 18.76 904 .05 .82 603 .05 .30 299 .05 .80 899 .10 .86 698 .10 .34 294 .10 .84 894 .15 .90 593 .15 .38 289 .15 .88 889 .20 .94 588 .20 .42 283 .20 .92 884 .25 .98 583 .25 .46 278 .25 .96 879 .30 14.03 578 .30 .51 273 .30 19.01 874 .35 .07 573 .35 .55 268 .35 .05 869 .40 .11 568 .40 .59 263 .40 .09 864 .45 .15 563 .45 .63 258 .45 .13 .97859 17..50 14.19 .97558 20.50 16.67 .97253 23.50 19.17 853 .55 .23 552 .55 .71 247 .55 .21 848 .60 .27 547 .60 .75 242 .60 .25 843 .65 .31 542 .65 .80 237 .65 .30 838 .70 .35 537 .70 .84 232 .70 .34 833 .75 .40 532 .75 .88 227 .75 .38 828 .80 .44 527 .80 .92 222 .80 .42 823 .85 .48 522 .85 .96 216 .85 .46 818 .90 .52 517 .90 17.01 211 .90 .51 813 .95 .56 512 .95 .05 206 .95 .65 .97808 18.00 14.60 .97507 21.00 17.09 .97201 24.00 19.59 803 .05 .64 502 .05 .13 196 .05 .63 798 .10 .68 497 .10 .17 191 .10 .67 793 .15 .73 492 .15 .22 185 .15 .72 788 .20 .77 487 .20 !26 180 .20 .76 783 .25 .81 482 .25 .30 175 .25 .80 778 .30 .85 477 .30 .34 170 .30 .84 773 .35 .89 472 .35 .38 165 .35 .88 768 .40 .94 467 .40 .43 159 .40 .93 763 .45 .98 462 .45 .47 154 .45 .97 .97758 18.50 15.02 .97457 21.50 17.51 .97149 24.50 20.01 753 .55 .06 451 .55 .55 144 .55 .05 748 .60 .10 446 .60 .59 139 .60 .09 743 .65 .14 441 .65 .63 133 .65 .14 738 .70 .18 436 .70 .67 128 .70 .18 733 .75 .22 431 .75 .71 123 .75 .22 728 .80 .27 426 .80 .76 118 .80 .26 723 .85 .31 421 .85 .80 113 .85 .30 718 .90 .38 416 .90 .84 107 .90 .36 713 .95 .39 411 .95 .88 102 .95 .39 .97708 19.00 15.43 .97406 22.00 17.92 .97097 25.00 20.43 703 .05 .47 401 .05 .96 092 .05 .47 698 .10 .51 396 .10 18.00 086 .10 .51 693 .15 .55 391 .15 .05 081 .15 .56 688 .20 .59 386 .20 .09 076 .20 .60 683 .25 .63 381 .25 .13 071 .25 .64 678 .30 .68 875 .30 .17 065 .30 .68 673 ..35 .72 370 ..35 .21 060 .35 .72 668 .40 .76 365 .40 .26 055 .40 .77 663 .45 .80 360 .!■') .30 049 .45 .81 /1;V/I/. )',S'AS' OF nh'h'Ji. 227 S|)(l(!illc L'l'iivilv at l'(!r c.rnt.. I'cr <'i;lll. K|i(;cinc I'lir mill. ]'i-r cent. HfiitcM\v. l'«r cent. ' I'cr writ. illiM.liol hy Illnilliil by irriivlty lit 0.96715 iilcoliiil liy ulcoliol by gruv llv at ulinAutl hy,al(y>hy Cd" i.'. vmIiiiiic. 25.50 20.85 vdIiiiiiu. 28.50 23.38 volume. wclKlit. ().!)70ll 0,y«3(K) 31.50 25.94 0:51) .55 .89 709 .55 .42 353 .55 .98 ():{:{ .60 .93 704 .00 .47 347 .(Kl 26.03 O'JH .65 .98 698 .65 .51 341 .05 .07 {)'i:\ .70 21.02 692 .70 .55 335 .70 .11 018 .75 .06 087 .75 .60 329 .75 .16 012 .80 .10 681 .80 .64 323 .80 .20 007 .85 .14 675 .85 .08 316 .85 .24 001 .IM) .19 669 .90 .72 310 .90 .28 .i)(;'js)() .95 .23 664 .95 .77 304 .95 .33 .•.)(;!)!) 1 26.00 21.27 .96658 29.00 23.81 .90298 32.00 26.37 !)Srt .05 .31 652 .05 .85 292 .05 .41 080 .10 .35 61(1 .10 .89 285 .10 .46 975 .15 .40 640 .15 .94 279 .15 .50 'J()l) .20 .44 (;35 .20 .98 273 .20 .54 \)M .25 .48 629 .25 24.02 267 .25 .59 1150 .30 .52 623 .30 .06 260 .30 .63 958 .35 .56 617 .35 .10 254 .35 .07 949 .40 .61 611 .40 .15 248 .40 .71 942 .45 .65 605 .45 .19 241 .45 .76 .9()1)37 26.50 21.69 ,96600 29.50 24.23 .96235 32.50 26.80 982 .55 .73 594 .55 .27 229 .55 .84 926 .60 .77 587 .60 .32 222 .60 .89 921 .65 .82 582 .65 .36 216 .65 .93 915 .70 .86 576 .70 .40 210 .70 .97 910 .75 .90 570 .75 .45 204 .75 27.02 905 .80 .94 504 .80 .49 197 .80 .06 899 .85 .98 559 .85 .53 191 .85 .10 894 .90 22.03 553 .90 .57 185 .90 .14 888 .95 .07 547 .95 .62 178 .95 .19 .96883 27.00 22.11 .96541 30.00 24.66 .96172 33.00 27.23 877 .05 .15 535 .05 .70 166 .05 .27 872 .10 .20 529 .10 .74 159 .10 .32 866 .15 .24 523 .15 .79 153 .15 .36 861 .20 .28 517 .20 .83 146 .20 .40 855 .25 .33 511 .25 .87 140 .25 .45 850 .30 .37 505 .30 .91 133 .30 .49 844 .35 .41 499 .35 .95 127 .35 .53 839 .40 .45 493 .40 25.00 120 .40 .57 833 .45 .50 487 .45 .04 114 .45 .62 .96828 27.50 22.54 .96481 30.50 25.08 .96] 08 33.50 27.66 822 .55 .58 475 .55 .12 101 .55 .70 816 .60 .62 469 .60 .17 095 .60 .75 811 .65 .67 463 .65 .21 088 .65 .79 805 .70 .71 457 .70 .25 082 .70 .83 800 .75 .75 451 .75 .30 075 .75 .88 794 .80 .79 445 .80 .34 069 .80 .92 789 .85 .83 439 .85 .38 062 .85 .96 783 .90 .88 433 .90 .42 056 .90 28.00 778 .95 .92 427 .95 .47 049 .95 .05 .96772 28.00 22.96 .96421 31.00 25.51 .96043 34.00 28.09 766 .05 23.00 415 .05 .55 036 .05 .13 761 .10 .04 409 .10 .60 030 .10 .18 755 .15 .09 403 .15 .64 023 .15 .22 749 .20 .13 396 .20 .68 016 .20 .26 744 .25 .17 390 .25 .73 010 .25 .31 738 .30 .21 384 .30 .77 003 .30 .35 732 .35 .25 378 .35 .81 .95996 .35 .39 726 .40 .30 372 .40 .85 990 .40 .43 721 .45 .34 366 .45 .90 983 .45 .48 228 FOODS. Specific Per cent. Per cent. 1 Specific 1 Per cent. Per cent. Specific Per cent. Per cent. gravity at alcohol by alcohol by 1 gravity at alcoliiil by alcohol liy gravity at alcohol by alcohol by 60° F. volume. weight.' j 6U° F. 1 Toluiiie. weight. GOOF. volume. weight. 0.95977 34.50 28.52 0.95560 j 37.50 31.14 0.95107 40.50 33.79 970 .55 .56 552 .55 .18 099 .55 .84 9G3 .60 .61 645 .60 .23 091 .60 .88 957 .65 .65 538 .65 .27 083 .65 .93 950 -.70 .70 531 .70 .32 075 .70 .97 943 .75 .74 523 .75 .36 067 .76 34.02 937 .80 .78 516 .80 .40 059 .80 .06 930 .85 .83 509 .85 .45 052 .86 .11 923 .90 .87 502 .90 .49 044 .90 .15 917 .95 .92 494 .95 .54 036 .95 .20 .95910 35.00 28.96 .95487 38.00 31.58 .95028 41.00 34.24 903 .05 29.00 480 .05 .63 020 .05 .28 896 .10 .05 472 .10 .67 012 .10 .33 889 .15 .09 465 .15 .72 004 .16 .37 883 .20 .13 457 .20 .76 .94996 .20 .42 876 .25 .18 450 .25 .81 988 .25 .46 869 .30 .22 442 .30 .85 980 .30 .60 862 .35 !26 435 .35 .90 972 .35 .55 855 .40 .30 427 .40 .94 964 .40 .69 848 .45 .35 420 .45 .99 966 .45 .64 .95842 35.50 29.39 .95413 38.50 32.03 .94948 41.60 34.68 835 .55 .43 405 .55 .07 940 .55 .73 828 .60 .48 398 .60 .12 932 .60 .77 821 .65 .52 390 .65 .16 924 .65 .82 814 .70 .57 383 .70 .20 916 .70 .86 807 .75 .61 376 .76 .25 908 .75 .91 800 .80 .65 368 .80 .29 900 .80 .95 794 .85 .70 360 .85 .33 892 .85 35.00 787 .90 .74 353 .90 .37 884 .90 .04 780 .95 .79 345 .95 .42 876 .95 .09 .95773 36.00 29.83 .95338 39.00 32.46 .94868 42.00 35.13 766 .05 .87 330 .05 .50 860 .05 .18 759 .10 .92 323 .10 .65 852 .10 .22 752 .15 .96 316 .15 .59 843 .15 .27 745 .20 30.00 307 .20 .64 835 .20 .31 738 .25 .05 300 .25 .68 827 .25 .36 731 .30 .09 292 .30 .72 820 .30 .40 724 .35 .13 284 .35 .77 811 .36 .46 717 .40 .17 277 .40 .81 802 .40 .49 710 .45 .22 269 .45 .86 794 .46 .54 ,95703 36.50 30.26 .95262 39.50 32.90 .94786 42.50 35.58 695 .55 .30 254 .55 .95 778 .56 .63 688 .60 .35 246 .60 .99 770 .60 .67 681 .65 .39 239 .65 33.04 761 .66 .72 674 .70 .44 231 .70 .08 753 .70 .76 667 .75 .48 223 .75 .13 746 .75 .81 660 .80 .52 216 .80 .17 737 .80 .85 653 .85 .57 208 .85 .22 729 .85 .90 646 .90 .61 200 .90 .27 720 .90 .94 639 .95 .66 193 .95 .31 712 .95 .99 .95632 37.00 30.70 .95185 40.00 33.35 .94704 43.00 36.03 625 .05 .74 177 .05 .39 696 .06 .08 618 .10 .79 169 .10 .44 687 .10 .12 610 .15 .83 161 .15 .48 679 .15 .17 603 .20 .88 154 .20 .53 670 .20 .21 596 .25 .92 146 .25 .57 662 .26 .23 689 .30 .96 138 .30 .61 654 .30 .30 581 .35 31.01 130 .35 .66 645 .35 .35 574 .40 .05 122 .40 .70 637 .40 .39 567 .45 .10 114 .45 .75 628 .45 .44 ANALYSIS OF Hi: hit. 229 Hpeclflc I'or coiit. I'or <;(!nt. Hiii'dlic \'>T cent. I'or rout. 1 HrN-niflc I'ftr cl liy itlcoliol l)y Uriivlty III (10" F. alroliDl l>y iilcoliol l,y gruviiv lit al(»>hol liy alcohol Uy voluiiiu. woi^lit. 36.4H VolllMU!. wui|{lit. 38.75 volutiiv. welKhl, 0.94(;2() 43.50 0.94 1 88 46.00 0.93824 48.00 40.60 01 2 .55 .5;{ 179 .05 .80 815 .05 .65 ()0:{ .60 .57 170 .10 .84 805 .10 .69 nor) .65 .6'J 161 .15 .89 796 .15 .74 M(\ .70 .6<; 152 .20 .93 786 .20 .78 57 H .75 .71 143 .25 .98 777 .25 .83 r,7() .80 .75 134 .30 39.03 7G8 .30 .88 mi .85 .80 125 .35 .07 758 .35 .92 .V);; .90 .84 116 .40 .12 749 .40 .97 514 .95 .8!) 107 .45 .16 739 .45 41.01 .94530 •1 1.00 .",6.93 .94098 46.50 39.21 .93730 48.50 41.06 527 .05 .98 089 .55 .26 721 .55 .11 511) .10 37.02 080 .60 .30 711 .60 .15 510 .15 .07 071 .65 .35 702 .65 .20 502 .20 .11 062 .70 .39 692 .70 .24 4<);3 .25 .16 05.", .75 .44 683 .75 .29 484 .30 .21 044 .80 .49 679 .80 .M 476 .35 .25 035 .85 .53 664 .85 .38 467 .40 .;',o 02() .90 .58 655 .90 .43 459 .45 .31 017 .95 .62 645 .95 .47 .94450 44.50 37.39 .91008 47.00 39.67 .93636 49.00 41.52 441 .55 .44 .93999 .05 .72 626 .05 .57 433 .60 .48 990 .10 .76 617 .10 .61 424 .65 .53 980 .15 .81 607 .15 .66 41 G .70 .57 971 .20 .85 598 .20 .71 407 .75 .62 962 .25 .90 588 .25 .76 398 .80 .66 953 .30 .95 578 .30 .80 390 .85 .71 944 .35 .99 569 .35 .85 381 .90 .76 934 .40 40.04 559 .40 .90 373 .95 .80 925 .45 .08 550 .45 .94 .94364 45.00 37.84 .93916 47.50 40.13 .93540 49.50 41.99 355 .05 .89 906 .55 .18 530 .55 42.04 346 .10 .93 898 .60 .22 521 .60 .08 338 .15 .98 888 .65 .27 511 .65 .13 329 .20 38.02 879 .70 .32 502 .70 .18 320 .25 .07 870 .75 .37 492 .75 .23 311 .30 .12 861 .80 .41 482 .80 .27 302 .35 .16 852 .85 .46 473 .85 .32 294 .40 .21 842 .90 .51 463 .90 ..37 285 .45 .25 833 .95 .55 454 .95 .41 .94276 45.50 38.30 267 .55 .35 258 .60 .39 250 .65 .44 241 .70 .48 232 .75 .53 223 .80 .57 214 .85 .62 206 .90 .66 197 .95 .71 Determination of Methyl Alcohol. ^ — Method of Leach and Lythgoe.- — This method depends upon the fact that the specific gravities of the two alcohols are nearly alike, but that the refractions are very different. Starting with methyl alcohol at per cent, (water) and increasing the ^ Personal communication from H. C. Lythgoe, Chemist, Food and Drug Department, Mass. State Board of Health. ' Jour. Am. Chem. See, 1905, p. 964. 230 FOODS. amount of alcohol, the refraction increases until it reaches a maximum at about 50 per cent, alcohol, beyond which point, with increasing; alcohol, the retraction diminishes until a])Solute methyl alcohol is reached, which has a lower refraction than water. Witii ethyl alcohol, starting as before at per cent., the refraction increases with increiising alcoholic strength much more rapidly than is the case with metyhl alco- hol, reaching a maximum at about 78 per cent. It then decreases slightly, absolute ethyl alcohol having about the same refraction as 51 per cent, alcohol. To determine methyl alcohol, prepare the alcoholic distillate as usual, determine the specific gravity, and obtain the per cent, of alcohol from the table. Determine the refraction of this distillate at 20° C. by means of a Zeiss immersion refractometer. This refraction should be then compared with those given in the table for that per cent, alco- hol. If the refraction corresponds to that of ethyl alcoliol, the alcohol is pure ethyl alcohol. If it corresponds to that of methyl alcohol, the alcohol is pure methyl alcohol. If it is between these figures, the alcohol is a mixture of ethyl and methyl alcohols. Two or three examples of actual cases, as found in the routine in- spection of foods and drugs in Massachusetts, will best illustrate the method of calculation. For determination of total alcohol from the specific gravity, Hehner's alcohol tables were used, (1) A lemon extract, found by the polariscope to contain 4.9 per cent, of lemon oil by volume and 90.20 per cent, of alcohol by volume at 15° C, Nvas freed from lemon oil by diluting four times with water, treating with magnesia in the regular manner, and filtering. A meas- ured portion of the filtrate was then distilled, and the distillate made up to the measured portion taken. This distillate was found to have a specific gravity of 0,9736, corresponding to 18,38 per cent, alcohol by weight,^ and to have a refraction of 35,8 on the Zeiss immersion refractometer. By interpolation in the table the readings of ethyl and methyl alco- hol corresponding to 18.38 per cent, alcohol are 47,2 and 25,4 re- spectively, the difference being 21,8. 47,2 - 35.8 = 11.4, (11,4 -- 21.8) 100 = 52,3. In this case 52.3 per cent, of the alcohol present was methyl. (2) An orange extract was found with 1.5 per cent, of orange oil and 83.2 per cent, of alcohol by volume at 15° C. Specific gravity of the :^-strength distillate, freed from oil as in the case of the lemon ex- tract, was 0,9754, corresponding to 16,92 per cent, alcohol by weight. Refraction of the distillate at 20° C, was 42.0. Readings of ethyl and methyl alcohol of 16.9 strength are, according to the table, 44,3 and 24,5 respectively. Difference, 19.8, 44.3-42 = 2,3, (2.3-19.8) 100 = 1.2. Thus 1.2 per cent, of the alcohol present was methyl, 1 Our methyl-ethyl alcohol tables being most conveniently worked out on the weight per cent, basis^ the per cent, by weight rather than by volume of the dilute distillate is here taken. Percentage of total alcohol in the extract, as well as of lemon oil, we com- monly express by volume. In this case the specific gravity, 0.9736, corresponds to 22.55 per cent, alcohol by volume. The per cent, by volume of total alcohol in the extract, 90.20 at 15° C, is found by multiplying 22.55 by 4 to correct for the dilution. yi ;v. I /. r,s7.s' ()/'• iiF.F.n. 231 TiKADlNfiH OK Kxi'KIMMKNTAI, MrXTCKKS OK \h TKVI, AND IVflfVI, A I/.'OHOIA M<4liyl lilcoliol. Klbyt alcohol. I'cr ccill. iilcohcl liy SC(ll(! rciidliiK, H|). Ur. ir.'M!. weight. 20'^ (;. Ah jiropurcfl, Ah rriiiiid, Ah iin.'imn.'d, AHrrtiirul, '.)i.;!(; .s:}.0 per (;t!iit. 08.52 per i:ciil. 09.88 |H;r cent. \t*:T <«;nt. O.KIIH) 22.84 21.18 O.HliK) iH.y.C) h\.\) 'lo.OK 47.41 45.08 41.95 (),'.)'j;'.i» ■17.11 r,i.!) :5r).r.o 35.42 11.85 11.99 O.HIDO ui. ;',(■. 70.:', '22. K4 2:5.75 08.52 07.01 ().9:'.'J(') ■i;!.-i:{ (I'j.-t 21.71 21.88 21.71 22.05 o/.mm:', 'jr,.(; 1 :!7,'J 11 (.2:! 11 (.70 0.41 5.88 ().'.)'J07 ■IS.SC. 77.r) 12.21 11.77 :{0.05 37.09 ■ 0.1)75:} 17.00 :m.o 8.50 8.92 8.50 8.08 o.'.xifu; 2;{.i»'2 r)0.2 5.1)8 0.48 17.94 17.44 ScALK Rkadincis on Zei.ss Immersion Rkfractometeb at 20° C. Coruespondino TO Eacu 1'kr Cent, hy Wkkuit ok Kthyi> and Methyl Alcohoia >1 J3 Sciile r t'lldiiiKS. S Sciilc. readings. Scale readings. f-cale readings. O O a o o o ja o O o "3 o o o o Si o u "3 2 o o J3 o O .a o V "3 o o Si o 4-> -t-i S.5f "-1 ^ "3 "3 14.5 0) bo "3 "3 =3 "3 V "3 ">% .a &4 "3 S 14.5 30 32.8 69.0 00 37.9 96.2 90 16.1 98.6 1 14.8 16.0 31 33.5 70.4 61 37.5 96.7 91 14.9 98.3 2 15.4 17.6 32 34.1 71.7 02 37.0 97.1 92 13.7 97.8 3 1(5.0 19.1 33 34.7 73.1 63 36.5 97.5 93 12.4 97.2 4 16.0 20.7 34 35.2 74.4 64 36.0 98.0 94 11.0 96.4 5 17.2 22.3 35 35.8 75.8 65 35.5 98.3 95 9.6 95.7 6 17.8 24.1 36 36.3 76.9 66 35.0 98.7 96 8.2 94.9 7 18.4 25.9 37 36.8 78.0 67 34.5 99.1 97 6.7 94.0 8 19.0 27.8 38 37.3 79.1 68 34.0 99.4 98 5.1 93.0 9 19.6 29.6 39 37.7 80.2 69 33.5 99.7 99 3.5 92.0 10 20.2 31.4 40 38.1 81.3 70 33.0 100.0 100 2.0 91.0 11 20.8 3:3.2 41 38.4 82.3 71 32.3 100.2 12 21.4 35.0 42 38.8 83.3 72 31.7 100.4 13 22.0 36.9 43 39.2 84.2 73 31.1 100.6 14 22.6 38.7 44 39.3 85.2 74 30.4 100.8 15 23.2 40.5 45 39.4 86.2 75 29.7 101.0 16 23.9 42.5 46 39.5 87.0 76 29.0 101.0 17 24.5 44.5 47 39.0 87.8 77 28.3 100.9 18 25.2 46.5 48 39.7 88.7 78 27.6 100.9 19 25.8 48.5 49 39.8 89.5 79 26.8 100.8 20 26.5 50.5 50 39.8 90.3 80 26.0 100.7 21 27.1 52.4 51 39.7 91.1 81 25.1 100.6 22 27.8 54.3 52 39.6 91.8 82 24.3 100.5 23 28.4 56.3 53 39.6 92.4 83 23.6 100.4 24 29.1 58.2 54 39.5 93.0 84 22.8 100.3 25 29.7 60.1 55 39.4 93.6 85 21.8 100.1 26 30.3 61.9 56 39.2 94.1 86 20.8 99.8 27 30.9 63.7 57 39.0 94.7 87 19.7 99.5 28 31.6 65.5 58 38.6 95.2 88 18.6 99.2 29 32.2 67.2 59 38.3 95.7 89 17.3 98.9 232 FOODS. (3) 6.3 cc. of tinetiiro of iodine, after titration with N/10 sodium thio^;nlphate (in the regidar manner for deterniinini;' its strength accord- ing to the United JStates Pharmacopceia), was neutralized with N/10 sodium hydroxide and distilled, collecting 25.2 cc. of the distillate, corresponding to a dilution of 1 : 4 of the sample. The distillate con- tained 20.92 per cent, alcohol by weight ; refraction 27.5 at 20° C, indicating 99.0 per cent, of the alcohol to be methyl. There is no doubt that the alcohol in this case was entirely methyl, the slightly high refraction of the distillate being due to the presence of a slight amount of volatile substance formed by decomposition of the tincture of iodine. The accuracy of the method is shown in a general way by a series of experiments, the results of which are tabulated on ])age 231. Determination of Extract. — The extract may be determined di- rectly or, with the aid of a table, from the specific gravity of the deal- coholized beer. The direct method is more accurate, and is carried out as follows : Into an accurately weighed platinum dish, such as is used in the analysis of milk, weigh 5 grams of beer ; evaporate to complete dryness, and multiply the weight of the residue by 20. Approximately accurate results are obtained by reference to the fol- lowing table, after Schultze-Ostermann : BEER EXTRACT TABLE Specific gravity. 1 2 3 4 5 6 7 8 9 1.011 2.87 2.90 2.92 2.95 2.97 3.00 3.03 3.06 3.08 3.11 2 3.13 3.16 3.18 3.21 3.24 3.26 3.29 3.31 3.34 3.37 3 3.39 3.42 3.44 3.47 3.49 3.52 3.55 3.57 3.60 3.62 4 3.65 3.67 3.70 3.73 3.75 3.78 3.80 3.83 3.86 3.88 5 3.91 3.93 3.96 3.98 4.01 4.04 4.06 4.09 4.11 4.14 6 4.16 4.19 4.21 4.24 4.27 4.29 4.32 4.34 4.37 4.39 7 4.42 4.44 4.47 4.50 4.52 4.55 4.57 4.60 4.62 4.65 8 4.67 4.70 4.73 4.75 4.78 4.80 4.83 4.85 4.88 4.90 9 4.93 4.96 4.98 5.01 5.03 5.06 5.08 5.11 5.13 5.16 1.020 5.19 5.21 5.24 5.26 5.29 5.31 5.34 5.36 5.39 5.41 1 5.44 5.47 5.49 5.52 5.54 5.57 5.59 5.62 5.64 5.67 2 5.69 5.72 5.74 5.77 5.80 5.82 5.85 5.87 5.90 5.92 3 5.95 5.97 6.00 6.02 6.05 6.08 6.10 6.13 6.15 6.18 4 6.20 6.23 6.25 6.28 6.30 6.33 6.35 6.38 6.40 6.43 5 6.45 6.48 6.50 6.53 6.55 6.58 6.61 6.63 6.66 6.68 6 6.71 6.73 6.76 6.78 6.81 6.83 6.86 6.88 6.91 6.93 7 6.96 6.98 7.01 7.03 7.06 7.08 7.11 7.13 7.16 7.18 8 7.21 7.24 7.26 7.29 7.31 7.34 7.36 7.39 7.41 7.44 9 7.46 7.49 7.51 7.54 7.56 7.59 7.61 7.64 7.66 7.69 1.030 7.71 7.74 7.76 7.79 7.81 7.84 7.86 7.89 7.91 7.94 1 7.99 8.01 8.04 8.06 8.09 8.11 8.14 8.16 8.19 8.21 The figures at the head of the several columns represent the fourth decimal ])lace of the specific gravity. Example : Specific gravity, 1.0187 ; referring to 1.018 in the left-hand column and running out to the column headed by the figure 7, we find 4.85 as the percentage of extract for that gravity. ANALYSIS OF I'.FJCR. 23^5 Detection of Preservatives.- The |.iiiMi|.;iI [ncj-crvjitivc iihc<1 in b(!or is SMlicyllc, iKiid ; ticxl in irii|»i»il;iii(f i- (luuiidc of hodiiirii, wliidi, }i()W(W(ir, i.s not used to ;iny citn.sidcrnhlc fNliiil as ytX in llii.s country. Salicylic Acid. — Tlic ordiniiiv nictliod nC extracting by nic^mH of ctlior and tcslinji; the rcsidiu! left on evaporation of flic laftcr with ferric cld(»ridc, cainiot he used \\\ tlie examination of Ix-er, since kiln- dried malt contains a |»rinei|ile wliicli p;ives a reaction identical with that of .salicylic acid. 'I'Ik; following; method, devised hy Spica, i.«, however, .sati.sfa(!tory and n^liahle : y\cidify 100 cc. willi sidplmric acid, extract with ether, allow the se|)a rated ether to evaporate sp(»nfa- lUioiisly, and warm the residnc; gently with a drop of strong- nitri*- acid, whereby, if .salicylic acid is ])resent, pic^ric acid is formed. The ad; picratc witli its brinlit-yellow color, wliieh may be imparted to a woollen thread immersed in tiie iicjnid. Fluorides. — Several methods are recommended, and amon^'' them the followin*:; : Method of IIefjoi.mann and Mann. — Expel the carbonic acid fi'om 500 oc. of beer, and then add 1 cc. of a solution containing 5 per cent, each of calcium and barium chlorides, and follow it with 0.5 cc. of 20 per cent, acetic acid and 50 cc. of 5)0 per cent, alcohol. Let stand twenty-four hour.s and filter. Dry the filter and precipitiite col- lected thereon without washinf>;, and transfer to a platinum crucible. Add strong' sulpluu'ic acid, and cover the crucible with a waxed watch- glass with some lines scratched through the wax coating, then heat at 100° C. for two hours, and observe the effect on the exposed gla.ss. This method is said to be of sufficient delicacy to detect the presence of 7 milligrams in a liter. Brand's Method. — To 100 cc. of beer made slightly alkaline with ammonium carbonate and hciited, add 2 or 3 cc. of a 10 per cent, so- lution of calcium chloride. Boil for a few minutes, filter, and dry the filter and contents. Then proceed as in the method just described. In either process, it is best to place a lump of ice in the concavity of the watch-glass to keep the latter cool ; the water should be removed from time to time by means of a pipette so that it may not overflow. Other Determinations. — Of minor interest are the determinations of acidity and ash. Total Acidity. — To 10 cc. of beer freetl from carl)ouic acid by shak- ing, add a few drops of neutral litmus solution, and then add deciuor- mal sodium hydrate until the end reaction is observed. Express the results in parts of acetic acid. One cc. of decinormal sodium hydrate equals 0.006 gram of acetic acid. Fixed and Volatile Acidity. — Concentrate 10 cc. of beer to a third of its bulk by evaporation, add water u|> to the original volume, and proceed as above. The difference in results is due to the acetic acid which has been driven off. The fixed acidity is due chiefly to lactic acid, and, if desired, may be so expressed. One cc. of the decinormal solution is equivalent to 0.009 gram of lactic acid. The other acids present include succinic, malic, and tannic. 234 FOODS. Ash. — The residue obtained in the direet determiuatiou of the ex- tract may be utilized for the estimation of the ash. Jt shoukl be ii>;nited very ciiutiously and at as low a temperature as possible until the ash becomes white. WINES. Properly speaking, Avine is the fermented juice of grapes, though the term is ajiplied also to other jn-oducts of fermentation of saccharine li(|uids and fruit juices. It has been in use as a drink from the very earliest jH'riods of civilization. At the present time, wines are pro- duced in inlinite variety and of many qualities. The character and properties dei)end u])()n a great number of factors, including the variety of the gra[)e, the nature of the soil upon which the vine is cultivated, the climate in general, and the state of the weather in particular Avhen the gra]")es are ri])ening, the degree of ripeness when gathered, the method followed in the preparation of the must, and the care with which the other steps in the making of the final product are conducted. Of very great influence is the extent to which the seeds, skins, and stems of the fruit arc allowed to l)e acted upon. The seeds yield con- siderable amounts of tannic acid, and the skins lend color, flavor, and to some extent astringency. The most important constituent of the juice of the grape is the sugar, and this is present in greatest abun- dance when the fruit is fully ripe. In the making of wine, the first step is the preparation of the must. The grapes, with or without preliminary careful examination and sort- ing, usually without, are crushed by machinery or by the naked feet of men, so that the juice is set free. Sometimes, the stems are first carefully eliminated, and particularly good individual grapes are cut out and set aside for special use. In the crushing of the fruit, the method of treading has in its favor the fact that the seeds are not thereby affected, and so do not give up so much of their astringent principle. If a white wine is to be made, the must is freed at once from the skins and stalks ; but if the jiroduct is to be red, these are retained during the process of fermentation. The juice of both the white and the black varieties of grapes is practically without color ; but when the dark skins are left in contact with the fermenting mass, the alcohol formed extracts the yellow and blue coloring matters, which become red under the action of the free acids formed at the same time. The constituents of the must are water, sugar, proteid matters, gununy substances, pectous matter, organic acids and their salts, and mineral matters. The must, with or without the skins and seeds, is fermented in vats of wood, marble, or stone, the process starting very quickly, being in- duced by organisms which grow on the skin itself. The temperatiu-e at which this is allowed to proceed exerts an important influence in determininar the character of the wine: conducted between 5° and 15° C, the ])rocess is comparatively slow and the aroma of the wine is rich ; while at higher temperatures, the rate is more rai)id and the bouquet is WINKS. 2.'}5 less in;irl<('y (i(!H,s;i,( ion oC (,li(i cvdliition of (•;iil(()iiin;.r;ir uill lie the llrsi, to \n\ exiijinslcd, :ind llie wine will lie "dr\-." It i~ sometimes liof'-cssiirv to iidd nilroj^'enons ni;illei', sni'li ;is ('^■^ nlliinnin or ^eljifin, in order to keep the process IVoni ee;isinti- <*'" '•■'ii'lv. As the pefeenliiy-e of ;deohol in llie fei'mentinj; nnisl rises, the liit;ir- tnite of polnssinni present is dejiosiled l' r.idn;dly, owiii^ to its ilisolu- hility in nleohol. The deposit is known eonitnerei;dlv ;is jir^'ol, ;mk1 is the soiii'c(> of ere.'ini oC l;irt;ir. When the (irst lennentation is coin|)leted, the nlcoholic; licpiid is drawn off into casks, in whlc^li it is kejit for a number of months, the vessels hcincj kept constantly lilled. It now iindero;oes a second .slow fermen- tation, which l)rin<;s about chan<;'es which are not imderstood excepting in their o^foss result, which is the production of tlx; "l)r)U(juet" or Ha,vor. In this second process, there occur a iiirther dcjif»sition of argol and an oxidation of aldehyde to acetic acid. The bonquet is due to a combination of ethers, the chief of which is cenanthic ether, sujv- posed to be produced from the alcohol through the agency of the organic acids normally ])reseut. The wine next is racked otf into other casks, and in some causes it is necessary to do this several times. Sometimes, the api)e:irance of the wine is such that "tining" is necessary. This consists in the addition of egg albumin, isinglass, or other gelatinous matter, which in its descent attracts and enmeshes the line particles of matter which nttt only pre- vent brilliancy, but later ou may impair the keeping (piality of tlie wine. Classification of Wines. — Wines are classified variously according to color, strength, sweetness, and content of carbonic acid. .Vccord- ing to color, they are classed as red or white, the latter term applying not only to the very light, almost colorless kinds, but also to those having a decided yellowish or even yellowish-brown color, such as is possessed by " white port." The red wines include those generally known as Clarets and Burgundies, though both these kinds exist in the white forms. The white wines include the white Clai'ets commonly designated as Sauternes, white Burgundies of which Chablis is a type, the Rhine and INIoselle wines, and oth(M-s. According to strength, wines are classed as natural and fortified. The natural wines contain of alcohol only that which is formed in the process of natural fernientatiou ; the fortified wines, such as Sheriy, Port, and Madeira, contain, besides, a considerable amount in the form of added spirits. 236 FOODS. According to their content of sugar, wines are classed as sweet or dry, Some of the sweet wines contain added sugar and that which has escaped the action of the yeast plant. lu the dry wines, all or nearly all of the sugar has been converted into alcohol. Not all of the sugar, however, in any wine is converted into alcohol and carbonic acid, small amounts going to form glycerin and succinic acid. According to their content of carbonic acid, wines are classed as still or sparkling (etfervescent). The natural wines contain j-tractically no carbonic acid ; the sparkling, or effervescent, wines, as Cham]>agne and sparkling ]\Ioselle, are in a sense artificial in that they are subjected to a jn'ocess of fermentation in the bottle, sugar being added for the pur- pose. They are flavored also with liqueurs. Composition of Wines. — Alcohol. — The most important constitu- ent, the active principle, of wine is ethylic alcohol. The higher alcohols, propylic, butylic, and amylic, are always present in traces. The amount of alcohol is variable, ranging in natural wines from 6 to 14 per cent, by weight, but ordinarily present between the limits of 9 and 12 per cent. In fortified wines, the amount ranges from 12 to about 22 per cent., but is usually about 17 per cent. Sugar. — While the amount of sugar in the original must ranges be- tween 12 and 33 per cent., in the natural finished product it is as a rule quite low, ordinarily considerably under 0.5 per cent., and often none at all. The sweet Tokays contain exceedingly variable amounts, ranging from 3 to 26 per cent.. Ports and Madeiras about 4, and Sherries somewhat less ; but American Ports, Sherries, and Madeiras are commonly fairly rich in sugar. Domestic Champagnes, also, con- tain notable amounts, but those of foreign origin, even those ordinarily classed as sweet, contain but small amounts, the impression of sweet- ness being largely due to the flavorings of the liqueurs added. Four specimens analyzed by the author, one of which (No. 4) is well known as an extra sweet wine, yielded the following results : Brand. Sugar. Extract. Alcohol by- weight. 1. Brut Imperial (Moet & Chandon) 2. St. Marceaux 3. Dry Imperial (Moet & Chandon) 4. White Seal (Meet & Chandon) 1.35 1.52 1.56 4.76 3.27 3.21 3.18 6.88 11.15 10.38 10.85 10.23 Extract. — The extract, or residue, represents the sum of the non- volatile constituents, including sugar, nitrogenous matters, tartaric and other acids, mineral and organic salts, coloring and astringent prin- ciples, glycerin, etc., all of which are present in but small quanti- ties. In "sweet wines, the principal constituent of the residue is sugar. The actual food value of the residue is, apart from the sugar, practi- cally nil. Adulteration of Wines. — Wines have been subject to a wide variety of adulterations from the earliest times, and measures against WINES'. 237 etiiess and hody, of alum to liei^/lifi-n color and of deeoloi-i/in^ aij^enlsto r(!tnov(! it, the suhstilution of uh'tlly artificial eonipounds, and proeesses for the " imj)rovernent " of the nalui'al |)roduet. Tiie (lax'oi'inn- and eolminn; agents are a.s a rule fpiitc liarndess. They are employed chiefly in the manufacture of factitif)UH wines, and not uneomnionlv the same a^^ent serves in both capacities. J^runes, raisins, dried apples and ])eaches, and dates arc commoidy fK) oniployed. Various berries, loofwood, alkanet, red beets, coal-tar products, and a wide variety of" other substances are said to be used for impartino; color. The addition of alcohol is recognized as a legitimate practice in the case of the ibrtified wines ; that of glycerin has no sanitary significance. The amount of alum used for heightening color is so small as t*> be productive of no harm. The employment of decolorizing agents is, like the substitution of artificial pi'oducts, a fraud pure and simple; but the use of preservatives, such as salicylic acid, formaldehyde, and sulphites, is objectiouable on account of danger to health. For the improvement of wines, a number of processes are in v(»gue. Chief of these is " plastering," which consists in the addition of g>'p- sum to the must for the purpose of securing a more brilliant appear- ance and increasing the keeping qualities. This agent deconnwses the potassium bitartrate, forming tartrate of calcium and acid sulphate of potassium, ^vhich latter eventually is convertefl into the neutral sulphate. Chaptali/.ing consists in the neutralization of the acidity of the must by the use of marble dust, and the addition of cane sugar or glucose. This process diminishes the natural acidity and increases the yield of alcohol. Galliziug consists in diluting the must so as to reduce its acidity to a given standard, and adding a sufficient amount of cane sugar or glucose to insure the producti(^u of the proper alcoholic strength. The Pasteur treatment of wnnes is resorted to sometimes as soon as evidence of untoward fermentations producing the so-called " wine dis- eases" appears. The wine, best in the bottle, is heated to from 55° to 65° C according as the alcoholic strength is high or low, whereby the existing germs are killed and the preservation of the wine is made permanent. The manufacture of artificial wines is carried on extensively in this country and abroad, in spite of the fact that fair grades of the genuine product are obtainable at very low prices. A number of hand-books and guides to the "art of blending and compounding" are pub- lished for the use of wholesalers and retailers of wnnes and liquors, and from several of these the following are selected as examples of the 238 FOODS. methods given: (1) Port: cider, 30 gallons; alcohol, 5 gallons; syrup, 4 gallons ; kino, h ]Knind ; tartaric acid, } ]ionnd ; jiort wine flavor, () ounces. (2) Claret: California hock, 40 gallons ; extract of kino, S ounces ; essence of malvey flower, 8 ounces. (8) Sherry : e([ual parts of Spanish sherry and California hock. (4) A\'hite wine : dissolve 25 pounds of grape sugar and 1 of tartaric acid in 25 quarts of hot water, ;uld 75 quarts of cold >vater and 50 ]x>unds of grape pulp, stir, cover, let ferment for four or five days, and strain. In France, an artificial substitute for wine, known as " ])i(juette," is manufactured very extensively from raisins and dried apples. It is estimated that in 1898 no less than 50,000,000 gallons were made and consu'.ned. The ]irocess is exceedingly sim})le. To each gallon of water used are added 1 pound of raisins and 1 of dried api)les ; the mixture is placed in an open vessel and allowed to stand three days. It is then bottled with | teaspoonful of sugar and a small piece of cinnamon in each bottle. It is said to be a pleasant and harmless l»ovorage. Analysis of Wines. Determination of Alcohol. — The })rocess for the determination of alcohol is the same as that folhnved in the analysis of beer, exce])t that the distillation or evaporation is carried farther. At least 60, or better 75 cc, are collected by distillation or driven off' by open evapo- ration. Determination of Extract. — The specific gravity of the de-alcohol- ized ^\ine gives, as with beer, an approximate estimate of the amount of extract, and the same table may he used. The direct determination is made by evaporating 50 cc. of the wine in a weighed platinum dish on a water-bath and drying to constant weight in an air-bath. With s\veet wines, a smaller amount is preferable. Determination of Acidity. — The total acidity, due to Intartrate of potassium, tartaric, malic, and other acids, is reckoned as tartaric acid. Twenty-five cc. of the wine are titrated in the usual way with deci nor- mal sodium hydrate, 1 cc. of which equals 0.0075 gram of tartaric acid. The volatile acids are reckoned as acetic acid. Fifty cc. of the wine are placed in a distilling flask connected by means of its outlet tube with a Liebig condenser, and, by means of a bent tube passing through its stopper and ]irojecting well below the surface of the wine, with a flask containing 250 cc. of water. The contents of both flasks are brought to the boiling-point, and then the flame beneath the wine is turned down and the current of steam passed through until 200 cc. of distillate are collected. This is titrated with decinormal sodium hydrate, and the result is expressed as acetic acid. The determination of the amounts of the individual acids is of no hygienic interest. Determination of Sugar. — The amount of sugar in wine is deter- mined by reduction of Fehling's solution, by the method of Allihn, and by polariscopy. For the details of these methods, the reader is referred ANA/,y.S/S OF WISKS. 2'V.) t<) Jiiiy of tlu! .staiidiinl works on wine ;iii;ilyHis, for (lie Hiiiall jimoiirit of Mii^Mi- <»i'(liii!irilv |»i-('S(!iil is (if lnif liltic li\ ^^iciilc itilcrcHt, ami the (IcMcriptioii (((■ Ihc |)r(iccsscs would i(<|iiii-c ;iii ;iiii()iiiit (»(' hpaa; va«tly out ol' |)rrr;ilnr(' ;is |)ossilil('. Detection of Coal-tar Colors. — Whilf the |)i(--cnc<' (.(' coal-tar (rolors is not. diilicnil of (|('t<'ction, the idcntifK alion of the iiuiividiial mcndxTS of the t;ron|) is hy no means easy. The foljowin^r te.-ts jrive reliable^ indic^ations of I he |ii-cscnce of this class of color-. I'.fjiiaJ vohinuis of wine and el lier, aiiilaled in a llasls, and let stand and -epa- ratc, will show in I lie el her la\-er a vrA coloration, if anilin eohtr- are present. in place of ellier, nilro-hen/ene may he used ; this removcH fuohsin, eosin, and niel liylen-hlne, hnt does not take n|> any of the vc'f»;otahle eoloi's, safranin, or indieo-cjirmine. Amyl alcohol, also, will become reddened when agitated with wine containing anilins, but the wine must fu-st be made slie;htly alkaline. I f white woollen threads are immersed tor some time in the colored lifjiiids, they will take up the colors and become dyed. Cazeueuve's test is performed as follows: To 10 ee. of wine add 0.20 i2;ram of mercuric oxide, then shake for one minute, boil, let stand, and filter. The iiltrate should be clear, and in the absence of anilins should be colorless; if it is red, an anilin color is present. Absence of color is, however, not conclusive evidence of purity, since a number of the anilin colors, as eosiu, raethylen-blue, and others, are whollv precipitated, and so do not ai)]iear in the filtrate Safranin, methyl-eosin, Ponceau red, antl a nund)er of other colors are precipi- tated ])artially or completely. A number of these, including safranin, Bordauix red, and Ponceiiu red, may be separated by the following process : To 200 cc. of wine from which the alcohol has been expelled, add 4 cc. of 10 per cent, hydrochloric acid and some white woollen threads, and boil for five minutes. Withdraw the threads and wash them with cold water acidu- lated wdth hydrochloric acid, next with hot watcu- similarly acidulated, and lastly with distilled water alone. Boil the threads in 50 cc. of distilled water containing 2 cc. of strong ammonia water, remove them, and immerse new ones. Make acid with hydrochloric acid and boil for five minutes. Varying shades of rose-red will be imparted to the threads if any of these colors are present. Fuchsin may be detected by the following methods : (1) To 100 cc. of wine add 5 cc. of ammonia water and 30 cc. of ether, and shake. Remove the ether, which will have no color, place it in a watch-glass with a w'hite woollen thread, and let it evaporate to diyne^s. If even a trace of fuchsin is present, the thread Avill show a distinct rose-col- oration. (2) Mix 2 volumes of wine and 1 of solution of basic ace- tate of lead, warm gently, and shake. Filter, add to the filtrate a small amount of amyl alcohol, shake again, and remove the amyl alco- 240 FOODS. hoi. If this has a red color, it may ho due to fuchsin or to orseille. To a portion of the colored liquid add hydrochloric acid ; if the color is discharged, it was due to fuchsin. To another portion add ammonia water; if tlie coli)r is chauo-ed to purple violet, it was due to orseille, Detection of Preservatives. — Salicylic Acid. — Spica's method for detecting salicylic acid in wine is as follows : Acidify 10 cc. of wine with a few drops of hydrochloric acid, and shake with an equal volume of ether. Remove the ether, filter it if necessary, and evaporate to dryness. Add a drop of nitric acid, warm gently, and add an excess of ammonia and 1 cc. of water. Immerse a white Avoolleu thread, apply gentle heat, and then withdraw the thread, wash it, and dry it l)et\yeen pieces of hlotting-paper. A yellow color indicates that sali- cylic acid was present in the wine. Anotlier method, for which great delicacy is claimed, even to a tenth of a milligram in a liter, is the follo^ying : Acidify 50 cc. of wine, beer, or other liquid with sulphuric acid, and shake it with an equal volume of a mixture of equal parts of ether and naphtha. Separate the ether, filter, and evaporate down to 5 cc. ; then add 3 cc. of water and a few drops of very dilute solution of ferric chloride, and filter through a wet filter. In the presence of salicylic acid, the watery por- tion will have a violet color. A modification of this method consists in extracting with ether alone, and then extracting the ether residue with naphtha ; the residue on evaporation of the naphtha is treated with water and very dilute ferric chloride. Fonnaldeliyde. — To 10 cc. of wine, add a few drops of milk known to be free from formaldehyde, and shake in a test-tube. Next pour down the side of the tube about 4—5 cc. of strong commercial sul- phuric acid, and note the color at the line of contact of the two liquids. (See under Milk.) Sulphites. — To 200 cc. of wine (or beer) add 5 cc. of phosphoric acid ; distil 100 cc, using a Liebig condenser with a bent delivery tube which dips below the surface of 20 cc. of decinormal solution of iodine. By distilling in a current of washed COj, the danger of back suction is avoided. The reaction which is brought about is as follows : SO, + 2H,0 + I, = H,SO, + 2HI. The amount of SO, may be determined by estimating the excess of iodine by means of standard sodium thiosulphate, or the distillate may be acidified with hydrochloric acid and the contained sulphuric acid precipitated as barium sulphate by the addition of barium chloride. One milligram of barium sul- phate is equivalent to 0.2748 milligram of SO,. CIDER. Cider, or apple wine, is the fermented juice of the apple. It is made very extensively wherever apples are grown, and is a very important product, viewed either as a beverage or as the basis of what is regarded generally as the best kind of vinegar. A very large, if not the greater, part of the cider produced is made l)fSTf/JJ':i> ALCOHOLIC 11 EVER AGES. 2)1 without spcc.iiil can; hy a very siinplc pnicc-s. '\'\\i- ;i|)|iI('.h iik(;(1 are onliiiMi'ily lliosc. not rii;irl-tri;ilI >'\/v, ^rccmujMH, ov(;r-i'i|)('n('SH, or hniiHcs ; l»iil (iCtcn pi i I'l ri IViiii i- ii.-cd when tlu; rrf)p is HO jthimdanl fli:tt IIhtc is nioic piolil In coiinciI iii^^ it into cider and vinegar llian in sending;' il in hnrrds lo market. 'I'lic ("rnit i.s {/n»nnd to a |>iil|) and pressed, :ind the juice is dr;i\\n into Icirrel- ;ind ;illourd to ("crnicnt. I (" tlic same arnonnt (if care is t:d\en as is jriven to llic niakinj;' oC wine Crorn grapes, tlic product is of" a siij»crior jrradc, an'ely sujrar, is in inverse propoi'tion to tlie amount f)f alcohol ; in average samples, it amounts to from 4 to (> i)er cent., while in new sweet cider it is commoidy neiirer \) })er cent. The free acids, ciiieHy malic, amoimt to less than 0.75 per (;ent., and average about 0.40. The adulterants of cider are water and salicylic acid. The latter ia found very commonly in that which reaches the city markets. PERRY. ^ Perry, or "pear cider," is the fermented juice of pears. It is made in the same way as cider. Pear juice being richer in sugar than apple juice, it follows that the average content of alcohol is somewhat higher than in cider. Distilled Alcoholic Beverages. Spirits, or distilled liquors, are the product of distillation of fer- mented sugar solutions. Their most important constituent is ethylic alcohol, which is ordinarily present to the extent of about 45 per cent. When freshly made, they contain variable small quantities of higher alcohols, furfurol, fatty acids, and other volatile principles, which together constitute what is known as fusel oil, the chief constituent of which is amylic alcohol. Each kind of grain or other raw^ material from which the ferment- able sugar solution is obtained yields a diiferent kind of fusel oil ; dif- ferent because of the changing relative proportions of its constituents, Avhich include butylic, propylic, aud amylic alcohols, and their corre- sponding acids, butyric, propionic, and valerianic, and other mattei-s. That wdiich is foimd in potato spirits is richest in amylic alcohol, and is the most toxic, while that from grapes contains bv far the least and produces the least harm. During the process of aging, the constituents of the fusel oil undergo chemical changes Avhicli result in the formation of oenanthic, acetic, and butyric ethers, acetate and valerianate of amvl, and other compounds, which together constitute the aroma or " bou- 16 242 FOODS. qiiet." Thus, a spirit is iinj)ri)veil in two ways by long' storage : it loses in toxieity and gains in flavor. The relative toxieity of the several alcohols and of other eonstitnents of fusel oil has been determiued by Dujardin-Beauinetz and others, who show that the ]wisonous properties increase with the boiIing-])oint and nioKruhir weiglit, Jeflroy and Serveaux ' determined the amounts in grams necessary j)er kilognini to kill a rabbit, as follows : ethylii; alcohol, 11.70; ])ropylic alcohol, 3.40; bntylic alcohol, 1.45; amylic alcohol, 0.G3 ; furfurol, 0.24. Daremberg^ found by experiment that artificial spirits and wines made with jiure rectified alcohol are less toxic than the gxnuiine products, by reason of the absence of the constituents of fusel oil. Roubinowitch,'' speaking of the greater toxicity of the higher alcohols, calls attention to the fact that the distillates from cider, perry, and fermented grains, potatoes, and molasses, are much more toxic than brandy. Most spirits are colored artificially by the addition of harmless col- oring agents, the mt)st ^videly used of which is caramel. As the prac- tice of coloring is in response to the demand of the consumer for a darker color than can be obtained otherwise, it can hardly be regarded as an adulteration. BRANDY. Brandy is obtained by distilling wines of the poorer qualities, often mixedj with the " lees," or dregs from the wine casks, and the " marc," or solid refuse left after pressing the grapes. The lees and marc are used also alone for the production of a highly odorous brandy, which is much used for improving the flavor of other brandies, and for giving flavor to the artificial brandies made from pure alcohol and -water. From this marc brandy is obtained the oily substance, oeuanthic ether, which is known commercially as '' oil of wine." Brandy is produced very largely in France, and much less exten- sively in Spain, Portugal, and Germany ; in California and in the wine- groAving region of the Ohio and Mississippi Valley, it is produced in large quantities and of most excellent quality. The colorless distillate is stored for some time in oaken casks, from which a small trace of tannin and a varying depth of amber (tolor are acquired. The flavor, which in general dej)ends upon the kind of grapes, their condition when pressed, and the care observed in the making of the wine, becomes improved during storage. The liquor is then colored and l)ottled for the market. Good brandy should contain from 39 to 47 per cent, of alcohol by weight, should have an agreeable odor and taste, and should be free from substances added to impart sharp taste and apjiai'ent strength. The nearly dry residue from 100 cc. very slowly evaporated on a water- bath should have a pleasant odor, and its taste should be neither sweet nor sharp ; a sharp odor points to the presence of fusel oil derived from 1 Arcliivijs (lu Medecine expdrinientale et d'Anatoniic patliologifjue, 1895, p. 569. ^ Ibidem, p. 719. » (iazctt^ des Hopitaux, 1895, p. 237. WHISK ICY. 243 |M)i;i(<) or ccnials ; ;i sweet liisle is iiidieiilive of ;ulro|)oi'lions. J>y oni; ("oniinla, i( is made with 5 parts «»rfetian- tliie, ellier, I of acetic ellier, '5 of tinelin-e oC^rjdls, 1 of tinefnre of |.i- iiufnlu, and 100 ol' alcohol ; hy another, it consists of" 15 |iarts of a<'elic ethel', 12 of sweel spirit of nitre, and I of rectilled wood spirit. Ono part, of either of these mixdires is snilieieiil to (lavor a mixtnreof 1000 j)arls of alcohol and (idO of water. As examples of the wa\' in whieli fiditions hrandy is made, the ff,|- lovviiifi:; will sefNc : (!) I'oil o onnees of raisins and G of St. JoImi'h bread in water, liltcr, and make up to JO (jiiarts ; mix this with 20 (puu'ts of iilcohol, 10 omiees of hrandy essence, and \ onnec of essc;nce of violetj Howers. (2) Dissolve 1 |»onnd of arjrols and .'> of snpir in a ;rain or potatoes. The raw materials from which the mash is made include malt, wheat, rye, corn, oats, and potato. In the process of mashinii;, the starch of the ^rain is chanlcte, the distillation is begun. The first distillate, known as " low wine," is re-distilled. The second distillate is stronger and less rich in fusel oil, which, being less volatile than ethylic alcohol, comes over chiefly in the later })ortions. The new whiskey is stored for sev- eral years, in order that it may acquire the flavor due to the formation of new compounds from the constituents of the fusel oil. During stor- age, it takes up a trace of tannin from the oak of the casks. The flavor of whiskey depends upon the nature of the raw material, and largely upon the aging process. The disagreeable flavor and odor of new wdiiskey are due to fusel oil ; the smoky taste of Scotch and Irish whiskies is due to the smoke of the peat and turf fires over which the malt is dried. Indian corn whisk v has a much different flavor 244 FOODS. from that of rye whiskey ; this flavor is regarded highly by many to whom rye whiskey is unpahitable and insipid, and at the same time it is so full that to others it is rank and nauseating. The peculiar flavor of Bourbon whiskey, so-called ix'cause originally produced in Bourbon County, Kentucky, is due to the corn from which, with ]'\e, the mash is prepared. Whiskey of .good quality should contain about 45 per cent, of alco- hol by weight, ;ind should yield not more than 0.25 per cent, of resi- due, which shouUl have a slightly aromatic odor and but little taste. AVhiskey is manufactured very largely from alcohol, water, and various flavoring compounds, some of wdiich can hardly be looked upon as wholly innocuous. The following directions are taken from a small Nvork, the object of which is, according to the preface, " to give the dis- penser of liquors thorough and practical information by which he will be enabled to compound, and blend liquors for his own purposes, and thus secure the additional profit." 1. Bourbon Oil. — Take of fusel oil, 64 ounces ; acetate of potassium and sulphuric acid, each, 4 ounces ; and black oxide of manganese, 1 ounce. Dissolve h ounce each of sulphate of copper and oxalate of ammonium in 4 ounces of water, mix all in a glass percolator, and let rest for twelve hours. Then percolate and put into a glass still, and distil 64 ounces. 2. Rye Oil. — ]\Iix 64 ounces of fusel oil, 8 each of oenanthic ether, chloroform, and sulphuric acid, and 2 of chlorate of potassium in 8 of water, place in a glass still, and distil 64 ounces, 3. BeadiiKj Oil. — ]Mix together 48 ounces of oil of sweet almonds and 12 of sul])huric acid, and when cool neutralize with ammonia and dilute with double the volume of proof spirit. " This is used to put an artificial bead on inferior liquors," For making the lowest grade of whiskey, one is directed to mix 32 gallons of alcohol and 16 of water, 4 ounces of caramel and 1 of beading (h1. ^y adding oil of rye or oil of Bourbon, " making the result rye whiskey or Bourbon, as the case may be," the value is said to be increased. From another similar source the following recipes for factitious whiskey are taken : 1. Bourbon Whiskey — Proof spirit/ 100 gallons ; pear oil, 4 ounces ; pelargonic ether, 2 ounces; oil of wintergreen, 13 drachms in ether; wine vinegar, 1 gallon ; caramel color, a sufficient quantity. 2. Old Bourbon. — Alcohol, 40 gallons ; Bourbon whiskey, 5 gal- lons ; sweet spirit of nitre, 2 ounces ; fusel oil, 2 ounces. Mix and let stand four days. 3. Old Rye. — Soak a half peck of roasted dried jieaches, put them ' Proof spirit is defined by an act of Parliament as a diluted spirit which at 51° F. shall weigh exactly twelve-thirteenths as much as an equal measure of distilled water. It contains half its volume of alcohol of sp. >lioli<; eonlcnt of rum is very variable, ranging from .'>() to over (!() ))er (^enl. by weight. Like other spirits, rum i.s very largely ;in artifuiial prochict of aliMiliol, \\;itg, centaury, and raspberry, but many other substanc(>s are used by dilferent makers. The fresh ])roduct has a very jironounced flavor, which is mellowed by age. The wines most used in making Fi'cnch vermuth are from the Rhone Valley, Picpoul, and from the southernmost parts of France. Italian vermuth differs materially from tht> French ; it is a much weaker infusion with a far more bitter taste. The materials used are in the main the same, but they are employed in very dilferent propor- tions. Vermuth contains about 17 per cent, of alcohol. Section 6. CONDIMENTS, SPICES, AND BAKERS' CHEMICALS. The condiments include a large number of food accessories which, while they are themselves of no nutritive value in the amounts which it is possible to eat, serve a very useful purpose in imparting flavor, and in stimulating appetite and digestion. Among them are some which act through free acids, some through volatile oils, some through resinous matters, and one, perliaps the most important of all, common salt, through itself alone. Some are simple substances ; as vinegar, salt, and the spices ; while others are combinations of a number of ingredi- ents blended according to definite and, as a rule, secret formulas ; as sauces, chutueys, catsups, and curries. Only when these compounded articles contain substances injurious to health can they be regarded as adulterated. The tomato catsups are preserved very commonly with salicylic acid or other preservatives, and colored with anilin dyes. Thus, of 25 samples of different makes examined in 1897 by the health authorities of San Francisco, 20 contained salicylic acid, 2 contained this agent together with borax, and 1 contained formaldehyde; 16 were artificially colored, mostly with coal-tar colors. Of 39 examined by the Massachusetts State Board of Health during 1899, 15 contained salicylic acid and 13 benzoic acid. VINEGAR. Vinegar is a weak solution of acetic acid resulting from the acetous fermentation of saccharine solutions which have undergone alcoholic fermentation. It contains, in addition to acetic acid, small and unim- portant amounts of alcohol and aldehyde, and extractive matters in varying amounts, according to the nature of the original liquid. The VINI'XJA R. 247 ;ut(itio .'icid cf)iil;i.iiic(l in the |)r()^ars, and not less than 0.2o ^ram of apple ash in 100 cc. (20° C.) ; and the water-soluble ash froni 100 cc;. (20° C.) of the vinegar contains not less than 10 millif^rams of plios- j>liorie acid (P„0,_), and rcMjuires not less than 30 cc. of decinormal acid to neutralize its alkalinity. Wine Vinegar. — In wine-])rodiicing countries, the vinegar in com- mon use is made from the cheaper kinds of wine. It has color or not, according to the kind of wine from which it is made. The so-calletl white wine vinegar in common use in this country among the foreign- born population is a colorless product of the oxidation of dilute .spirits. Wine vinegar contains rather more acetic acier cent, of citric acid, and should \ield from O.oO lo 1.00 per cent, of" a.sh. Its specific gravity should In', not less than 1 .0.'iO, and is usually above I.OlO. As it is (piieU to undern() decomj)osilioii in its natural cf)n- dition, a, number of methods have been proposed for \\< |)reservation, the best of w hi(^li ap[)ears to be, first to clarify it by means of strong alcohol, next to lilter or decant from the ])recipitatcd matters, and then to (>xpel the alcohol by heat. The clear juice may then be bottled and sterilized. Lime juice is the expressed juice of the sour lime, C'ltrns acidn, and of the sweet lime, C. limetta. It contains usually somewhat less acid than lemon juice, and has a lower specific gravity. It is preserved by the same method. As antiscorbutics, lemon juice and lime juice are of about equal value, and far sujierior to vinegar. Adulteration. — Lemon juice is much more subject to adulteration than lime juice, but both are falsified and imitated extensively. In fact, it would not be overstating the case to say that by far the larger part of the lemon juice sold in this country is wholly factitious. Com- monly, it is nothing more than an aqueous solution of citric acid ; some- times, it is flavored with oil of lemon. Its taste is much sharper and less agreeable than that of the genuine article. The residue is very different in character and appearance, and leaves practically no ash on ignition. Other acids are used sometimes in place of or in addition to citric acid. The one most commonly employed is said to be tartaric ; this is detected readily by the gradual formation of bitartrate of potas- sium on addition of the acetate. The mineral acids are said to be added not infrequently ; they are detected without difficulty by the common tests. SALT. The best grades of common salt are white, dry, free from dirt, and completely soluble in water. ]Many specimens of good quality contain traces of chloride of magnesium, which causes cakino:. In humid weather, even the best grade of salt absorbs moisture sufficient in amount to cause it to lose its dry, poAvdery nature. The addition of about 10 per cent, of corn starch serves to keep it dry and pow- dered. 250 FOODS. MUSTARD. Mustard is the flour oi' llu' seed o[' tlio l)ln(']c and llio wliitt' nmstard, Sinapis nlxjcr and aS', (iHhi. 'Tlic lirst luentioiicd is nuu'li tlie more pun- gent <>f the two; on beino- \\e( witli watei', a volatiU' oil is developed from two of its constituents. 'I'hc whiti' inustard yields no volatile oil by this trt'atment, but develops an acrid principle. Jioth varieties of seeds contain a bland iixed oil to the extent of 20-25 per cent. As this adds nothing- to the flavor, makes grinding more difficult, and exerts an injurious influence on the keeping qualities, it is removed from the whole seeds by pressure. Mustard is largely subjt'ct to adulteration with wheat, rice, and corn flour, with the farther addition of turmeric to restore the color lost by dilution. These substances are detected very easily by means of the microscope. Furthermore, since starch is wholly absent from pure mustard flour, if a small portion of a suspected sample, boiled in a little water in a test-tube and cooled, gives a blue or bluish-black color on the addition of compound iodine solution, it uuquestional)ly is adulterated. PEPPER. Pepper is the fruit of Piper nigrum, a perennial climbing shrub. The unripe berries, dried for several days after being picked, are known as Black Pepper. The ripened berries, dried and decorticated, are known as White Pepper. In the powdered form, in which they are retailed most commonly, both are adulterated very extensively with substances of a harmless nature. These include ground shipbread, corumeal, cocoanut shells, rice, buckwheat, oatmeal, mustard hulls, charcoal, olive stones, and a variety of other substances of little or no value, capable of being reduced to powder. The simplest method of determining the purity of this or any other form of spice is to reduce a specimen of the genuine unground sub- stance to powdered form and study its appearance under the microscope, and then to compare it with the sample in question. Each kind has its characteristic appearance, and so with a little practice one is enabled to determine very quickly the question of purity. By a similar study of the microsco])ic appearances of the common adulterants, these may readily be identified in the mixture. The chemical analysis is intricate and tedious, and not always conclusive. CLOVES. Cloves are the flower l^uds of Eur/enia caryophyllata, picked while red and dried in the sun. They contain about 1 G ])er cent, of volatile oil, easily removed and of considerable value. In the powdered form, cloves are adulterated commonly with allspice, clove stems, spent cloves, cocoanut shells, and other worthless matter. The ])resenc(^ of spent cloves can be determined only by estimation of tlie amoimt of volatile oil present. Clove stems show microscopically a very large B A KINO POWDERS. 261 J)r()|)ori.i(»li o(" I he so-c;illc(| sloiic (•ell-. Oilier :-iil),-.|;ilic,(;.s urc (1(;L(:<;U:(1 in tlu! iri.'iiincr (lcsciil)c {\\v. \y,\v\\ (>(" s('Vliij»l)rcad, nut sIk^IIs, and cedar sawdust. ALLSPICE OR PIMENTO. Allspice is ilie dried unripe herries o(" riiiiciild ii/llclii'i/i-'<. Altlionpli one o(" tlie cliea])est ol" spices, it. is adidtcraie*! extensi\'ely w itii ^rround sliipbreacl, cluircoul, nut shells, clove steins, and nnistinl hulls. GINGER. Ginger is the rhizome of Zhtf/iher oJ/lciii(i/c. Jt is one of the most commonly adulterated of condiments. Tlie snbstances u.sed include ground shipbread, rice, mustard hnlls, cayenne, turmeric, connneal, clove stems, and exhausted ginger from the maiuifiu'ture of the tincture. It is very rich in starch, whicli is diiferentiated ea.-ily from otiier starches. NUTMEG. Nutmeg is the inner kernel of the fruit of 3Tyrist}('a frograns. It is not eounnouly sold in the ]wwdered condition, but \vheu so sold is generally adulterated with the substances used as admixtures of other spices. MACE. Mace is the dried membranous covering, the arillode, of the nutmeg. It is adulterated with wild mace, cornmeal, and other cheap materials. CAYENNE PEPPER. Cayenne is not a true ]ie])per, but the powdered pods of several species of Capsicum, including C. annuvm and C faM'u/iatnm. Its appeai'anee under the microscope is very characteristic. The common- est adulterant is cornmeal. Among others are rice, mustard hulls, turmeric, and ground shipbread. BAKING POWDERS. Baking powders, like condiments, are in no sense foods, but being employed in the preparation of bread, in which are retained the ulti- 252 FOODS. mate products of the reactions of their component parts upon each other, tliey are of hygienic interest. They are employed for the produc- tion, within a short time, of a result which, when caused by the action of yeast, is only slowly brought about ; namely, the leavening of bread. Yeast produces the leavening gas, carbon dioxide, through slow fermenta- tion of a part of the carbohydrates ; while with the use of baking powders, this gtis is disengaged as a result of chemical action of one of the t\:)nstituents upon another in the presence of moisture, and chemical substances foreign to yeast-leavened bread are left as a residuum in the bread. AVhether this residuum is objectionable on the score of its in- fluence upon the system, depends upon the nature of the ingredients of the ]X)wdcr ; but aside from the question of disadvantage or inferiority on this account, it is a fact, genc'rally acknowledged, that bread made with baking powder is lacking in a certiiin agreeable flavor developed by the action of yeast. Baking jiowders are combinations of an acid or acid salt with sodium bicarbonate in about the proper proportions for chemical union, together with an amount of starch sufficient to keep the ingredients in a dry state, and hence mutually inactive. When the combination is introduced directly into the flour, and water is added to make the dough, the reaction occurs and carbon dioxide is set free. They are known, according to the nature of the acid salt, as tartrate, phosphate, and alum powders. Tartrate powders are made usually with " cream of tartar " (potassium bitartrate), but occasionally with tartaric acid, which is not only more expensive, but is objectionable from a practical standpoint on account of its readier solubility, which causes a too rapid evolution of gas. The reaction which occurs between potassium bitartrate and sodium bicarbonate has, as results, carbon dioxide, water, and potas- sium sodium tartrate, or " Rochelle salt " ; as follows : KHC,H406+NaHC03=KNaC4HA+C02+H20. The commercial advocates of other kinds of powders dwell upon the undesirability of aperient substances in bread, but the residuum of Rochelle salt in the amount of bread which one could eat in a day would be very much under the minimum dose from which any results could be expected. Cream of tartar, as retailed, is adulterated very commonly with gyp- sum, chalk, alum, and starch ; but as furnished to the manufacturer by the refiners, it contains but a very small percentage of a normal im- purity, tartrate of calcium. The usual chemical tests and microscopic examination reveal fraudulent adulteration very quickly. Good speci- mens contain at least 94 per cent, of bitartrate ; and 2 decigrams, dissolved in hot water and titrated with deci normal sodium hydrate, require for complete neutralization not less than 10 nor more than 10.6 cc. The presence of a small amount of tartrate of calcium is of no sanitary importance whatever, statements to the contrary in advertising matter notwithstanding. The phosphate powders are made with acid phosphate of calcium, FOOD PRKHERVATION. 253 wlii(;li coiiImIiis ordiiiiii'ily more nr Ir.^.- ,-iil|»li;ilc ;i:- ;i ii;itiii;il iiiijiiirity, 'V\n' rc^iu^l.ioii witli sodiiiin l)ic;ii'l)iiii,ilc i- ex |)ic.-:-;c(| ;i- Collowh : (;nll,,(l'<),,), j -JNiillCO, (iilII'O, , •S■.^,\\\'^)^ i '2C<>, ) *2II,0. 'riuirc! is no \V('ll-a;rt results t)t' preservation hy cold it is not always essential that the iood shall he frozen ; hut unless the temperature to \\hieh it is I'xposed is near or below the freezing-point, the iuHuence is only U'uiporary. l^iekino- in it'e serves very well lor short i)eriods to ship meats and tish throuo'h long distances, an!l<'l< (Ikm'MIis lull :iiid close llietil eoiiiplelcly, e\<-e|»l iiii.' a stiiall Ii(»lc, ihcii lo siilijcel llieiii In llie I em | lera t II I'e i.f Ixtiliiijr water, or iiinjici-, and lo r\i»r I lie hole willi .^ohjei'. 1 liey are tlieii relie.-iicd ;iri(| linally allowed l view of the author will stand the test of exclu- sion of oilier i)ossible and more probable causes. Oi" the small amounts ol" tin found in canned foods, Professor Attfield says that they are undeser\ing of serious notice, and lie questions that tl)cy represent the amount r(>gnlarly worn off of tin saucepans and kettles. Furthermore, it is the nearly unanimous opinion of writers of works on toxicology that the only compounds of tin that arc in any way poisonous are the chlorides, and even these are ignored completely by most of the lead- ing authorities. On the other hand, there is no limit to the testimony regarding the very great value of canned foods, csj^ecially in military operations on a large scale, and in expeditions of various kinds away from market cen- tres and other sources of supply. Lieutenant Grecly, Dr. Xausen, and other Arctic ex])lorers are unanimous in their praise. Greely, for ex- ample, says : " No illness of any kind occurred prior to our retreat, and those most inclined to canned fruits and vegetables were the healthiest and strongest of the party." Lord Wolseley, in speaking of their use- fulness in hot climates, says that " tinned provisions, meat or vegetables jHit up separately or combined in the form of soups, are jiractically un- dan\ageable by any climatic heat " provided they are of the best quality and have been properly cooked and enclosed in perfectly sound air- tight tins. " Given these conditions, nothing can be more admirable ; failing them, nothing more deleterious." In military operations in the tro]iics, where beef cattle cannot be taken along on the hoof and re- frigerated beef cannot be transported overland on account of speedy decomposition, canned meats are indispensable. 256 FOODS. How long properly oaniietl foods will rciiKiiu in good condition, can hardly be determined, but the evidence at hand points to indefinite preservation. In 1824, according to Letheby, a nnmber of tins of rantton were cast ashore from the wreck of a ship at Prince's Inlet ; eight years later, they were fonnd by Sir John Ross, and those which he opened were in good condition, although exposed during this time to alternate freezing and thawing. Sixteen years afterward, they again were found bv men from the ship Invedlgator ; and in 1868, forty-four years from the time they were cast ashore, the remaining tins, opened by Letheby, were found to be in a ])crfectly sound state. TyndalP makes mention of tins in the Royal Institution that had remained in good condition sixty-three years. Professor A. H. Chester, of Hamilton College, relates that in the summer of 1875 he hid a number of cans of corned beef under a stump in woods in the northern part of Minnesota, and five years later found them to be perfectly sweet, although they had been exposed to the heat and cold of five successive summers and winters. Again, a numljer of cans of meat and fruit, washed into the Genessee River in 1865, were dug out of the mud sixteen years later, and found to be unaltered. It is an unfortunate fact that the cupidity of some of our largest packing-houses has led to the canning of what is practically refuse meat, from which the constituents to which the desirable flavors are due have been extracted, and that in consequence the public mind has largely become imbued with a prejudice against canned meats in gen- eral. But it is not alone in this country that canned meats are some- times not what they purport to be. It is related that in France, in 1899, a packer of meats was sentenced to pay a fine and to serve eight months in prison for putting upon the market an immense amount of canned game and poultrs^, all of which had been made from the flesh of broken-down cab horses. Chemical Treatment. — Chemical preservatives are substances or combinations added to foods wdth the object of delaying or preventing their decomposition. They are used on the assumption that, while they accomplish the desired object, they are incapable of exerting any harmful influence upon the system of the consumer — an assumption tliat has not been demonstrated as based on sound reasoning. It is assumed that bad effects cannot be caused, because they are not mani- fested at once after the ingestion of small doses by persons in good health ; but this Is no proof that continued use may not result in serious trouble which may be referred t(3 some other possible cause. It is said that the preparations employed are in common use as valuable remedies in the treatment of the sick ; but it should be taken into consideration that, when used as remedies in morbid conditions, they are given for only a limited time, for the purpose of counteracting abnormal influences, and that the doses are regulated carefully under proper professional supervision. Their action in conditions of health 1 Floating Mattere in the Air, New York, 1882, p. 293. FOOD PRESKRVArrON. 257 ;ui(l (lisc.'isc iii.'iy he very (liircrcnt ; hiil uhctlicr so (»r not, one ^•^\\\ fiii(| no (^X(•,lls(' ("or llic iiif^(!Hti()ii ol (iii;iti\<' icincdicH hy u pcr'-oii in ;i rilaki ol' liciillli, vvlio,s(! ,sy,sl(!ni needs no -nch .-lid, for indefinite periodh iind willi no re^^idnlion of (Ik; size u[' I he do,-c. .Salicvlie aeid, for ex!iin|)l(!, is ii ]'(!inedy lioldin'i; ;i liinh |)osilion in tli(; treattnent. of rlieu- nialisni, but its vulne in lliis (-(indilion is no v;did exciiM; lor its adriiin- i.stnition day in and day ont lo those who never have felt tli(* twin^^e-H and |)ain of this disease;. It is much inon; niasonahle to assnnu; that (h'u^s which exert a powerCnl inMiienee ("or ^'•ood in nifirhid Ktates will exert an e(|iiaJ (K^^ree o(" inlhicncc for h;iriii in condiiioriH f)f' licJiltli. Moreover, it is to be considered ihnt the object of ehernieal treatment of foods is not to benefit the nneonseious eonKUinr^r, but to brin^ the larjijest possible financial I'etiirn to the mannfactnrer and |)nrvevor, to whom the health of" the eor)sinner may In; a matter ol" little eoneeni. In all fairness to the consumer, chemiwdly preserved foods slif)uld be so labelled that the purchaser may be informed of the nature and amount of the added substance, so that those who ob)(!(;t to the dietetic use of druj^s may not have the same forced upon them without their knowlcfl^r*.. The addition of ])reservatives to foods offered for sale is f"orbidden in almost all civilized countries, and several governments have enacted laws specially directed against individual drugs. Thus, France names IkiHc ucid, borax, salicylic acid, and sodium bisulphite; Austria names sali- cylic acid ; (u'rmany prohil)its all antiseptics, and especially boric acid and borates, and imposes additional penalties for the sale of chcmic^illy preserved foods to the navy. Massachusetts prohibits all preservatives except salt, sugar, niter, vinegar, and alcohol, unless the purchaser is informed of the nature of the substance used. In milk, all preserva- tives whatsoever are prohibited unconditionally. The substances used as chemical preservatives include boric acid and borax, salicylic acid, sulphurous acid, sulphites and sulphates, benzoic acid, formaldehyde, hydrogen peroxide, sodium fluoride, and others of minor importance. INIany of the commercial preparations in common use are combinations of two or more of these and other sub- stances. Thus, Venzke and Schorer ^ report the ingredients of 38 meat preservatives, analyzed by them, as follows : Salt, sugar, and saltpeter, (1); salt and sodium sulphite and sulphate (4); sodium sulphite and sulphate (4); the same, plus sugar and salt (1); salt and sodium bi- carbonate and nitrate (1) ; salt, boric acid, saltpeter, and sodium sul- phate (3); salt, boric acid, and sodium sulphate (1); salt, boric acid, gypsum, and sodium sulphate (1) ; salt and boric acid (0) ; salt, salt- peter, sodium and calcium sulphates, and cochiueal (1) ; salt and borax (1) ; salt, borax, and saltpeter {2) ; salt, borax, and sodium nitrate (2) ; salt, borax, sodium and calcium sulphates, and salicylic acid (1) ; borax and sugar (2). The rest consisted of single substances. A large proportion of 24 meat preservatives examined by Kammerer were found to be mixtures of borax and l^oric acid, and borax and so- dium sulphite ; 31 others examined by Kiouka were, as a ride, sodium 1 Deutsche Fleischerzeitung, 1893, XXI., Nos. 20, 21, and 24, IT 258 FOODS. sulpliite and sulphato, hut 14 liquid prciiarntions oonsistod chiefly of caK'iuiu sulj)liite and suljihatc, ami sodium sulphite, hisulphili', and sul- phate. Kirehiuaier has reported one as cousistinj;- of salieylie acid and sodium salicN'late and phosphate. Polenske foiuul boric ai'id (about 60 per cent.), saltpeter (about 12-14 per cent.), sugar, salt, and sodium salicylate (about 7.50 per cent.) in a specimen of sausage salt, and in a lunnbcr of other preparations sold untler fancy names. Of 7 other meat preservatives examined l)y him,' one contained salt, sodium sulphite and suli»hate, irou chloride, and vanillin, and the rest were combinations already described. A. C. C'liapman^ has reported a most extraordinary combination of aliiinimmi sulphate, salt, sodium nitrate, benzoic acid, iodic acid, sul- ])hurous acid, and chloral. ^Vnother, examined by Tollner, proved to be ammonium bromide, boric acid, borax, and sugar. Another, known as " Mayol," contained wood alcohol, ethylic alcohol, boric acid, anniionium fluoride, and glyc- erin. JNIeats preserved by means of it are said to show no trace of boric acid or ammonium fluoride beneath the brown coating, which forms to a depth of a millimeter. In this country, the favorite mixture is one of borax and boric acid, and this is S(»ld under many ditferent names. Boric Acid and Borax. — These substances generally are used together, for the reason that, although the acid has greater power as an antiseptic than the salt, the combination of the two is still more efficient. It is used very largely in butter to the extent of about a tenth of an ounce to the pound, and is dispensed with a generous hand in oysters, clams, and other fish, in sausages and other meat products, and '\n milk. With regard to the effects of boric acid and borax on the system, there is a decided difference of opinion among those who have investi- gated the subject, but it should be said that a number of the reports favorable to the use of these agents, ])ublished by commercial houses, suggest that the conclusions arrived at were inspired somewhat by financial considerations. Our knowledge of possible ill effects is de- rived chiefly from the clinical experience of those who have used the drugs internally and as washes and injections. It is a fact that many patients can take large doses of both substances for long periods with no apparent harm, but it is equally true that small doses and local applications have been a frequent cause of serious and even fatal results. Deaths have been reported from the use of 5 per cent, solu- tions in washing out the pleural cavity and lumbar abscesses, and from w^ashing out a stomach with a solution of half that strength. Numerous cases of troublesome cutaneous eruptions and of serious gastro-intestinal disturbances following internal and external use have been rejiorted within recent years. Plant ^ has shown that internal use may be followed by acute parenchymatous nephritis, and his conclusions have been endorsed by the experience of Fere, mentioned below. 1 Arbeiten aiis dem kaiserlichen GesiiiidhL-itsamle, VIII., 7). 686. ^ Analyst, Dec, 1898, ' Inaugural dissertcition, Wiirgburg, 1889, FOOT) I'llICSERVATION. 259 In I.S7fI, iJic iidniixliirc oC horn.x lo luillci- \v;is s;iiicli'»iMil i(irici;illy in l*'i';in('c ; Itiii seven yenrs l;iier, ;i ((iniinil tee of ^eien(i.'-ls, \vli<» in- vesli<;'!ii(^y l.lie inve>-li^;i(ionK of l*on(!li('l, \\\i\ nse of l)oi;ix wiis |)i-oliii)ile enii ;d1ecl tlienystetn liarni- fully. As is well known, borax has been used extensively in the treutrnent of e})ile|)sy und other diseases of the nervons system. J^-ofessor JI. C. Wood states thut, in his experienee, the most marked result from it« use in this direetion was severe ^astro-inlestinal irritation. Dr. Fcr6' has given a valnable re})ort of his results in the treatment of 122 crises of epilepsy by this drug, wliieli was given in beginning doses of 30 grains, inereased to as much as 5 draelims a day. Jn more than 70 per cent, of the cases, the treatment had no beneficial result ; in about 20 per cent., some temporary or doubtful improvement was seen ; and, hi 9 per cent., there Avas distinct gain. Jjut the great draw- back was the frequency of toxic effects and the danger of producing or aggravating lesions of the kidneys, even when given in small doses. Among the most common results were loss of a})petite and burning pain, followed by nausea and vomiting. Cutaneous affections were very common, and complete baldness was caused not infrequently. (This result has been noted by many other practitioners.) In some cases, a cach(>ctic condition, characterized by wasting, a waxy tint of the skin, puflfiucss of the flice, and even general oedema, was observed. In a number of cases of general axlcma, urannia developed with some suddenness. Dr. Grumpelt" has reported a case in which headache, nausea, and intense dryness of the skin followed the use of an injection containing a tablespoonful of boric acid to the pint. The effects disappeared with cessation of the treatment, but came on again Avith its renewal. Dr. J. J. Evans ^ has found, as a common result of the continued use of boric acid in cystitis and urethritis, an erythema followed by desquamation. Internal doses of 10 to 20 grains twice daily for five Aveeks caused in one instance total baldness. Experiments on man aud animals, by Professors iSIattem, Foi-ster, Chittenden, and Schleuker, have demonstrated that boric acid and borax interfere with digestion and nutrition. Mattern reported profound disturbances in dogs after a few daily doses of 8 grains ; ^ Revue tie M^dooine, September, 1895. =* British Medical Journal, Jan. 7, 1899. » Ibidem, Jan. 2S, 1899. 260 FOODS. diarrhoea and other signs of gastro-intestinal irritation, and in some instances even fatal results were caused. He himself took 30 grains, and suifered violent abdominal pain and diarrhoea. Forster and Sohlenker liave shown that doses of 8 grains have a decided etleet in preventing absorption of nutriment and causing intestinal irritation. Dr. Annett, of Liverpool, fed a number of kittens with milk containing :20 grains of boric acid to the quart, and all of them died in an emaciated condition at the end of the thii-d or fourth week. As to the effect of these agents on the dillerent processes of diges- tion, there is no agreement. Chittenden, for example, believes that boric acid increases the digestion of proteids, and that even 25 per cent, will not check gastric digestion of egg albumin. He has noted also a marked stimulant effect on pancreatic digestion of proteids following the use of borax. Leffmann and Beam, and others, however, have observed effects directly contrary to those reported by Chittenden. Chittenden's first experiments were made to determine the possible influence of borax and boric acid upon the processes of salivary, gastric, and pancreatic digestion. He calls attention to the fact that his results throw no light upon the influence of the agents upon the secretion of the dig-estive fluids. He shows that borax inhibits the action of saliva on starch, and boric acid in small amounts increases it, and also the power of the gastric juice to digest proteids. Later experiments by Chittenden and Gies ^ lead them to the conclusion that the two substances have no peculiar action on nutrition, and that, since elimination is complete within thirty-six hours, the possibility of cumulative action must be very small, even when moderate amounts are ingested daily. Tunnicliffe and Rosenheim ^ concluded, from a series of metabolism experiments on young children, that boric acid in doses up to ] gram per day, continued for some time, exerts no influence on proteid or phosphorus metabolism, has no effect on the assimilation of fat, and exerts no inhibitory effect on intestinal putrefaction ; that borax in con- tinued doses of 1.5 grams may or may not improve assimilation of fat, and tends to increase intestinal putrefaction ; that both boric acid and borax are eliminated quickly ; and that neither will affect the general health and well-being. Halliburton,^ experimenting with borax and milk in vitro, found that 1 part of borax in 1000 completely prevents the action of rennet, and that smaller amounts delay it. On the other hand, Liebreich,* experimenting with dogs, found that neither borax nor boric acid has any influence on metabolism ; that boric acid in saturated solution has no effect on the mucous membranes of the stomach and intestine, while borax in 2 per cent, solution has a ' New York Medical Journal, February 26, 1898. ^ .Journal of Hygiene, April, 1901, p. 168. 3 British Medical .Journal, July 7, 1900, p. 1. * Vierteljalii'sschrift fiir gerichtliche Medicin, 1900, p. 83. FOOD l'ni-:.SI':iLVATION. 201 markedly injurious ('(reel, (Iioml-Ii not so tmicli ;i- I |i(i- cent, ol -odiiiin hy(lrat,(! or O.T) |)cr cciit,. oC snllpclcr ; llmt •") jicr r-ciit. of lioiic ;i(if I mid 0.25 ))(!r cent. o(" hctrsix luivc no inlliicncc on L'li-I'i'' di;.'(-( ion, l»nt O.o per (!(!iit. ()(' boi'.'ix li.'is sii^lil inliiMlory iiftion ; tlint ncitlicr liiis any (vd'ccii, on {\\v. diocslioii oC sljirclics ; and llial holli arc cliniinat'd <|nicl Ik- ;iIT<'I<os(! other than to j)leasf; tin; eye. The p(5iH or <»ther veJ^(^lal)l(^s are boiled in a very dilnU; solntictn of (!0])jK'r suiphatti, - phyll, and is not itself I'elained, is jircposterous, lor if a solution of cliloro|)liyll is healed with dilute eop])er su]|)hate, the eoloi- is destroved and a hrowu prveipilate is produced ; wliilc if pericctly white boans are boiled for a short time in a solution of the same strength, they tiike on a de(>p-<2;reen color throuj^h the formation of a new compound with the contained le^umin or some other jiroteid. J*otator in pi-oteids, are affected but slightly by similar treatment, i>ut eggs may be colored intensely green. The liquor of canned greened vegetables is commonly free from cop]Kn', and the testing of siK'cimeus by adding ammonia to a portion of the liquor, in the expectation of ])roduciug a blue color in ease the vegetable has been so treated, is, therefore, without result. In order to determine the presence of copper, a few grams of the substance may be incinerated in a porcelain capsule, the residue therefrom treated with dilute hydrochloric acid, and the filtrate subjected to the usual tests. The question of the hygienic importance of small amounts of copper has been the subject of a number of extensive investigations on the part of individuals and foreign governments, and while it can hardly be said to be proved that danger can arise therefrom, nevertheless no good reason can be advanced in favor of the practice of greening. Two stu- dents in Ijchmaun's laboratory took daily doses of copper salts with no perceptible disturbance ; one took 39 milligrams of copper sulphate daily for 50 days, and then double that amount for 30 more ; the other took the acetate for 51 days in doses ranging from 16 to 9(3 milligrams. These amounts are larger than an average eater would be likely to take into his system from canned vegetables in the course of a day, for the entire contents of an ordinary tin — somewhat less than half a pound — commonly yield less than 50 milligrams of copper. According to Baum and Seelinger,- whose numerous experiments extended over a period of three years, small daily doses are, as a rule, completely absorbed and ag-ain eliminated ; larger doses are not com- pletely absorbed. Complete elimination may require as long as five ^ Seventh International Congress of Hvgiene, 1891. •^ Zeitsclirift fiir olieutliche Cliemie, 1S9S, p. 181. 266 FOODS. months from tbc dato of the last dose. Lono'-continned ino-cstion of small doses may bi'in<;" about a condition of chronic poisoning. Copper appears to be a normal constituent of some articles of food. The assertion, made originally by Meyer, of Copenhagen, that wheat and oats often contain minute traces, esju'cially in their husks, has re- peatedly been proved. According- to Lehmann,' the species of jilants has far less iniiuence on the amount taken up than the amount of copper present in the soil. He found the metal in a great variety of ])lants gi-owing in a copper soil : rye, oats, hops, potatoes, dandelion, juniper, violets, cherries, etc. In woody plants, the greatest amount of copper is in the bark. According to Karsten,- the sjjraying of grape- vines Avith copper solutions is not wholly free from objection, since that which adheres to the fruit may be sufficient to make their yield of wine toxic. He instances a number of cases of diarrluea and vomiting due to wine which yielded traces of copper. Lead. — Traces of lead are of common occurrence in various articles of food, especially those wrapped in foil or enclosed in cans having ex- posed seams of lead solder. A number of specimens of wrapping-foil, analyzed by Dr. Charles P. Worcester,^ yielded lead in amounts rang- ing from traces to 89 per cent. They are used largely for wrapping cream cheeses, chocolate, and other foods. The metallic caps used for closing glass jars of preserved fruits and vegetables are also sources of danger. One specimen examined by Worcester contained 93.5 per cent, of lead. Patent stoppers, consisting of a metallic disk Avith a border of rubber, used in bottles for summer beverages known to the trade' as "soft drinks," commonly contain lead, as is shown by Worcester's examination of 28 specimens, which yielded from 3.5 to 50.7 per cent. The contents of the several bottles yielded lead with- out exception; the largest amount was 1.05 milligrams. Dr. William R. Smith ■* has drawn attention to the common occur- rence of lead in citric and tartaric acids. The former is used consid- erably in making summer drinks, and the latter in eflFervescing powders and baking powders. Of a dozen specimens examined by him, only one was uncontaminated ; the highest amount found was 0.037 per cent. At the present time, canned foods are less likely to show traces of lead than formerly, when the cans were made with less care. In 1893, Wiley '^ reported traces in 132 out of 248 samples examined. Concerning the hygienic importance of small daily doses of lead, there is but one opinion. It is quite improl)able that the occasional use of canned vegetables containing but a fraction of a milligram in an entire can will lead to serious injury, l)ut the constant daily ingestion of appreciable amounts of lead is likely to lead to serious consequences in at least a fair proportion of cases. * Archiv fiir Hygiene, XXVIL, p. 1. ^ Cheniiker-Zeitnng, 1S96, p. 37. •' 29th Anniml Keport of the State Board of Health of MassachiisetfB, p. 570. * .Journal of State iSledieine, October, 1892. ^ Department of vigriculture, Division of Chemistry, Bulletin No. 13, Part VIIL (JONTAMINATION OF h'OODS 11 Y METAI.S. 207 l*]s|K'on;il;ed from 0.03 to 0.49 gram to the kilogram, reckoned a.s oxide ; in 17, it was present only in traces. We have no evidence that thes(> small amounts are of the slightest sanitary imjiortance. Nickel. — Nickel is emj)loyed sometimes in place of coj)per lor green- ing peas. About a quarter of a gram of the suljihate suffices for a kilogram of peas. It is dissolved in boiled water to which 10 cc. of a 2 ])er cent, solution of ammonia are added, and then the solution is diluted with boiled water in suilicient amount to cover the jX'as, which then are boiled for a few minutes, drained, and washed. According to E, Tjudwiff,'^ nickel is given off in small amounts to all sort.s of foods cooked in nickel dishes. He found from traces to 12.9 mdligrams per 100 grams of the food examined. There is no evidence that these amounts can produce injury. Tin. — Contcimination with compounds of tin is exceedingly common, and, so far as is known, is harmless and unimportant, the coni]>ounds, other than the chloride, being apparently incapable of produciiig any physiological or local action. Metallic Contamination from Kitchen Utensils. — Much has been said, from time to time, ccmcm-ning the possible danger of poisoning by small amounts of lead and other metals taken up by foods from kitchen utensils, and especially from glazed earthenware ; but a number of extensive investigations have demonstrated that this danger is very remote. Mussi ^ has shown that, if the tiring of lead-glazed potterj" 1 Chemikei-Zeitung, 1897, p. 721. '^ Foi-schnngsboviolU iiber Lehensniittel, etc., 1897, IV., p. 218. ^ Oesterreiolie Clioniisi-he Zoitiins::, 1898, I. * Giornale delta R. Societiv Italiana d'igiene, January 30, 1900, p. 1. 268 FOODS. has been done properly, no trace of lead will be taken up by acid foods, such as tomato soup, or even vinegar ; but he advises that all new vessels should be cleansed very carefully before using, on account of the common presence of lead dust on the glaze when fresh from the kiln. Riche ' also determined that with properly tired ware the danger of solution of lead is practically nil, the specimens used yielding no traces to boiling dilute acetic and nitric acids and salt solutions. But im- properly tired ware will yield traces. Enamelled ware is believed commonly to contain lead ; and the enamel, having a dilferent coefficient of expansion from that of the iron, being likely to crack and chip off, especially with careless hand- ling, is thought to be dangerous ; but Barthe " found no trace of lead in a number of enamels examined, and asserts that very hard enamels need neither lead nor any other poisonous compounds in their prepara- tion. This accords with the experience of the author and other American investigators, and it may confidently be said that the enamelled ware in common use is lead-free. Aluminumware, which has of late come into extensive use, is less acted upon by acid foods than tin, but is affected considerably by alkalies, the impurities present in commercial aluminum acting as favoring agents to its corrosion. But the resulting compounds are innocuous in the small amount ingested. This kind of ware is kept clean very easily and offers the great advantage of lightness. Nickelware is attacked but slightly by ordinary food materials, and the amounts taken up are without sanitary significance. But its cost is against its extensive use, and, moreover, it imparts sometimes a greenish tint, which is repugnant to the eye. 1 Revue d' Hygiene, August 20, 1900, p. 704. * Journal de Pharmacie et de Chemie, 1898, p. 105. Cll y\ I"I^ K \l I i. All:. Alii is a inixiiirc oi* ga.scs, mikI ih>( ;i (licinicil roitipomifl. (ritil tlic latter part of the Heventccnili (ciiturv (KiODj, il w.-i- >ii|i|»(im(I to l)(! Mil (ilciiicnt, hilt Jean Miiyow tluii proved it to he a iiiixliin- of }j:;!tse,s ; mikI hier, Lavoisier discovered the two ^ases, oxy^rcri ;irid niti-onxiii, \vhi(Oi, a hiiiidrcd years later, were separated hy l'rie-tl(y and hy ISeheele. Air is a colorless and apparently odorless niixtnre of" oxygen, nifro- f»en, a-r}2;on, (^arhonie- acid, a(|neoiis va|)or, and traees of other siihstanees. It is not, however, under ordinary conditions odorless, hut, on the con- trary, it contains various s(!eiits, to which we are so accustomed that, unless present in unusual degree, owing to local conditions, they are not perceived. This is noticed on returning to an ordinary atmosphere from one where the causes of the usual odors are absent or nearly so, as, for instance, from deep subterranean caves ; or from a room where the air is foul and oppressive, as, for instance, from a heated, over- crowded hall or street car. The air of the Arctic regions contains but little odor, on account of the absence of bodies which give rise to (xlors, and the proximity of any source of smell is noticed (piickly. The ex- plorer Nanseu ^ speaks of the pervading smell of soap wliich he noticwl when, after months of wandering, he met Jackson, wlio had been housed comfortably with all the common necessities of man. AVhile air is a mixture of gases, it is one of tolerably constant com- position, particularly in the case of its chief constituent, nitrogen. Under the conditions of life, the more important, but less abundant element, oxygen is subject to more or less variation. In the presence of vegetable life, particularly by day, it is increased slightly ; in the presence of animal life, it is diminished more or less. OXYGEN. The normal amount of oxygen is stated usually at just below 21 i>er cent, by volume. A. Leduc gives it at exactly 21, with 78.06 of nitro- gen and 0.94 of argon. Piiferent observers have reported the follow- ing as averages of large numbers of analyses of pure outdoor air : 20.99 Scotland. 20.98 Scotland. 20.94 Sweden. 20.92 France. 20.94 Germany. 20.92 Xorwav." 20.95 Ensiaiid. 20.95 Ohio. 1 Farthest North, Vol. II.. p 529. 2t?9 270 AIR. The mean of a luiiuhiT of analy.ses by Buuyen was 20.924 by volume, and of a Imndivd at Taris by Regnault, 20.900. For the sake of conveuieiKi', w u may disivganl the very slight ditteroiice between 21 and the ligiuvs (^)btaiiicd by exaet analysis, a ditferenee in the seeond phiee of (.leeiuials, and aeeept 21 as a normal. .\t great heights, the proportion of oxygen is less than at the surface. For instance, on the Faulhorn, in . Switzerland, 20.77 has been observed as the mean of a number of determinations. Under certain conditions, there is very slightly more than 21 jiarts ; for instance, in the immediate vicinity of vegetation, especially by day, there may be an excess of oxygen, but it is very small; sea air, taken in mid-ocean, has yielded 21.59, but ordinarily contains less than 21. It is less, by very small fractions, in the streets of cities than in the open country, and in towns than at sea. Oxygen is the element in air that supports all life. It is constantly being withdrawn from the air in the process of respiration, and is re- turned to it in chemical imion with carbon as carbon dioxide. This is absorbed by vegetation and split up, the carbon being retained, and the oxygen for the most part released and returned to the air. Thus, the processes of animal and vegetable life combine to maintain the equilib- rium. All animals do not breathe in the same degree ; birds have the most active respiration, and next come mammtds ; and all consume more oxygen when active than when asleep. Oxygen is essential to the germination of seeds, and to the growth of plants. Although plants take up carbon dioxide and exhale oxygen, they also breathe as do animals, absorbing the latter and exhaling the former. Even the anaerobic organisms consume oxygen, although living where air is wanting, for they split up combinations of oxygen and other elements. Thus, in dilute sugar solutions they withdraw some of the oxygen and s]:»lit up the sugar into carbon dioxide and alcohol. For sustaining animal life, it is essential that the air shall contain not far from the normal amount of oxygen ; that is, that it shall be neither much diminished nor yet over-rich in that element. Human life is impossible in air which contains but four-fifths of the normal amount, and equally so in an artificial atmosphere containing materially more than the normal. In man and animals, the tissues do not receive oxygen in the free condition, for when the air is inspired, the oxygen is taken up by the red blood corpuscles and unites with the haemoglobin to form an un- stable compound, oxyhsemoglobin, which, as the blood circulates through the tissues, is decomposed ; the oxygen is then taken up by the cells, and eventually returned to the blood in the form of carbon dioxide, and eliminated as such from the body. In an artificial atmosphere con- taining an excessive amount of oxygen, the haemoglobin becomes sat- urated with the gas, part of which becomes dissolved in the blood serum, and then acts as a poison to the tissues and destroys them. 15 NITlLOdHN. 271 I liS|»ii'c(| ;ii|- loses ;il)uill ;i (iiiiilli <>(' i(s (txy^cn, jiikI Ih r<;flirii('r ;i iliiilJ\- -ciilcd city hIiovvh no very rnuU-riiil varia- l,i(tii (Voiii (Ji;ii <>( I lie ii|icii coiiiil ly. 'V\\{'. Itiiins ;\vi' iicscr lillcd wllli |)iii-c air al'ici' ilic lir.-t rc.-)iiralioii ai birlli, since (lie\ are ne\ci- w linlK ciniil ie«l, and tlicy <;oiiM'(jiiciitly ntaiii it under prcsstin!. Jt lias be(Mi estimated that, IVom all Hf>iircs|)licrc lias ixil Ixcii ex |)l,iliii (| salisfaclofily. It lias an (Hl<»r iKil inilikc llial <»r (iiliiird clildrinc. 1 1 lias very stronj; oxidizing |>(i\v«t, iniich iiKirc so lliaii owucii, \\lii

  • |in~eiicc in ihe air of any place is fair evideiiee ol" IVeedom iVom oxidi/ahle matters. Ozone has an exeeedinijly irrifatinti; elleet on tlie res|)iralory mneoiis membranes, and when inhaled with o.wlicii in ihe |iro|)ort ion ol' I part ill 240, (jui(!kly pi'odiiecs death in aiiinial- siilijeeted lo it. it is bc- liovod to exert a perniinous inlhieiiee in inllaiiiinatory conditions of the hmt^s and bronehi, even when present in not nuu-li more, if any, than the ordinary ainoniit in the atmos|)here. We aotnally letertiiiti;i- lions by linhncr :ind \'on I ie\v:i>eiie\v ' denion-l i-;ite(| the ^.Meat inlln- enec ol" Imniidily in (his |>artieMlar. /\ I I"/' ( '. in moist air, the daily eliminaiion fell to 2 Mi f^rams, while in ilr\- aii' at the satin- tetiipcnitiirc it ros(! toHTI. The tale rises with the teni|»eratiir(' in both moist and dry air, and (he more promptly, (he e-reater (he drvncs.s. 'J'lie Older air contains coinnKtnly from (id to To per cent, of the amount lUHX^ssary Cor satnration. In some plaee> noted lor the dryiicHH of the air, tlie ainoiint is miieh below ; in other.-, where (he op|)ositcting blanket to the earth by preventing too great loss of heat by radiation. At night, the earth gives nj) ])art of the heat which it has absorbed during the day ; and when the air is very dry and the sky very clear, the temjicrature falls nnich more than when there is more vapor ]>reseiit to prevent loss by radiation. In the Sahara, after the hottest days, tlie nights arc generally very cool, the temperature fall- ing sometimes 30 to 40 degrees C. in a few hours. At high altitudes also, Avhere the blanket of vapor is thin, the fall in temperature at night is very marked. Absence of aqueous vapor jiermits the cooling process to begin as soon as the sun gets low, and ice may form in a few hours where, during the day, the sun's heat had been intolerable. This is seen in the great deserts and at high altitudes. It is noticed commonly that the first frosts of autumn and those which come occasionally in the middle and later parts of spring occur only on very clear nights with low humidity. An amount of watery vapor approaching saturation gives rise to dis- comfort, whether the temperature be high or low. The " sticky " days of summer and the " raw " ones of winter owe their disagreeableuess to their high relative humidity. In a hot saturated atmosphere, while transpiration can proceed, evaporation cannot, and hence the cooling influence of evaporation is missing. The sweat stays on the skin in the liquid form instead of passing into the air as a vapor, and the word "sticky" becomes singularly appro])riate. On the other hand, Mith low humidity and high temperature, the sweat does not condense and remain on the skin, but piasses into the air, and transpiration is not impeded in the lungs. Hence the great bearability of dry heat as ^ Arcliiv fiir Hygiene, XXIX., p. 1. 278 ATR conij);nvcl with moist. Saturation at low temperature has as great, if not iiTi'utor, inrtui'iuv on bodily t'oiuiort. It docs not follow that since ono fc't'ls the heat more acutely with hiiih relative humidity, this condi- tion will enable one to withstand the op])()site discomfort of cold. Indeed, the reverse is true. At low tem]ieratures, saturated air causes a cjreater withdrawal of heat than drv air, and intensifies the sensation of cold ; for moist air is a much better heat coiuhictor. Cold (by air is much more comfortable than air some degrees warmer but materially moist. In the very cold climate of eastern Siberia, the air is so dry that 50° to 60° below zero F. is no hardshi]"), provided one wears com- ]iletely dry clothing, while with moist clothing one would perish in a very short time. Some ])arts of Siberia are both cold and damp, and hence uninhabitable. Atmospheric moisture has, thei'efore, directly opposite effects ; it intensifies the effects of heat and also those of cold. DUST AND MICRO-ORGANISMS. Another normal constituent of the atmosphere — one of enormous importance — is dust ; normal, because it is everywhere in the atmos- phere, and because a perfectly dustless air is an artificial product obtained only with the observance of great care. The individual particles are very small, but at the same time very variable in size, ranging from those plainly discernible to the naked eye, to those of extreme minute- ness. Dust is organic and mineral, and has its origin in countless processes. It includes ])articles of animal matter, vegetable substances of every kind including bacteria and moulds, sea salt, matters swept from the soil by the action of winds, those discharged by volcanoes,' others from manufacturing establishments, from chimneys, and from the millions of meteorites which daily fall from iuterj^lanetary space. The ordi- nary combustion of illuminating gas yields millions and millions of particles of carbon for every individual cubic foot. Organic dust exists only in the lower strata of the atmosphere, but that of mineral origin is everywhere. Micro-organisms are very abundant in the air of inhabited rooms, and in general in that of toAvns and cities, less abundant in the country, and least at great heights and at sea. Experiments have shown that at an elevation above 6,300 feet the air is free from them. Pasteur exposed a large number of flasks of broth at an altitude of 6,000 feet, and obtained a growth in but one. Tyndall exposed 27 flasks at 8,000 feet, and got no growth whatever. Dr. Fisher- has shown that on the ocean, 120 miles from land, the air is usually free from organisms, and that at lesser distances — 90 miles, for exam])le — it contains but few. The air of cities contains thousands in every cubic meter, against ^ After the preat eruption in Java in 1883, a haze of extremely fine particles of pumice, estimated to be from seven to more tlian twenty miles above the earth, was visible in all parts of the world for several months. * 2feitschrift fiir Hygiene, I., p. 410. DUST AND MlCllO-OndASISMS. 279 Fio. 10. less lli;i,n .'I liiiii(| III llic sMiiic \iiliiiiic (i(" (■(iiMilrv ;iir. Il li;i^ hccii ('.;i-lcillii,(,(ul (li;il, ill (|(ii.-(|\ |H)|iiil.il((| jil;iccs, siicli ;i^ Loiidoii and Man- clicslc!!', Jill iii(li\ i(lii;il iiilialcs in IIk; (loiirsc of" an lioiir ii|)\vai°(l (>{' ■ I, 000, 000 of ^ci'ins and spores. I>iil tliis \\\:^u\'i' i- ciionnouhlv in cxf^iHH of (lie (i<;iir(! ^ivMMi hy l*'lri;^|^<',' wlio cshinalcs llial in scvcnfv ycarH a man may inlialc UT), 000, 000 hadcria, wliidi, lie HSiyn, is aLoiil wli.'it one swiiliovvs in 'JT) i'v. oC ordinarN- milk. '^riic nnmlM'rof Itadiria in air i> iiiMiiciHcil vorv Jjn'^itlv I)V drv winds aniire to l>ri<<;li(, sunshine. Moulds, on llie other hand, have heen oh.served hy Mi(piel to iiKirease i-apidl\' after a rainstorm, and to Im; mneh !(«« affeoted by winds. The a-vei'ai;'(> nnmher of oraanisms (nimd at Montsoiiri.- in an inves- tigation which lasted six years was A-)^ ])er eiilne meter. The lowest results were observed in February and the hi!i;hcst in July. Durin^; the same ])eri()d, the number in the air at the center ot" Paris was 3,910 ; the smallest figures were }ielded in January and the highest in INfay. All organisms are less numerous in the air at night, since then there is less mechanical disturbance of the earth's surface. While the nunxber of bacteria in outdoor nir may be fairly high, it should be borne in mind that the majority of them are of the harmless varieties, and that the jiathogeiiic kinds constitute only an infinitesimal ])ro- portion. Dust, as has been said, is of enormous im- portance. M ithout it there would be no rain, no fog, no clouds ; the air would be satu- rated with moisture, and every object would be continually wet. Dust is largely hygroscopic, and, there- fore, attracts the watery vapor of the atmos- phere, thus becoming the nucleus for a drop of rain or particle of mist. Were it not for ^Xuro/dustto rSf^anS'fi^.' its presence in the air, the aqueous vapor would condense without rain on every tree and plant, ever}- rock, every dwelling, every living creature, and, in short, on every object to which air has access. That atmospheric dust is necessary for the ]n-odnction of rain and fog, may be demonstrated very sim]ily by condensing moisture from a saturated atmosphere through lowering of the temperature, and noting * Grundi-ist; der Hvijiene, 1897. 280 AIR. what occurs when dust is present or absent. For this purpose a simple apparatus, such as is shown iu Fig. 10, is all that is required. This con- sists of a large tlask fitted with a rubber stopper, tlu'ough which pass two pieces of glass tubiug, to the free ends of which pieces of rubber tubing with pinehcocks are attached. The glass tubes project beyond the shoulder into the body of the flask. If we pour into the flask an amount of Arater rather more than suffieient to fill the neck when tlie Hask is inverted with the stopper in position, we have the conditions necessary for complete saturation of the confined air with watery vapor. If now we withdraw by suction through one of the rubber tubes a small amount of the ct)ntaiued air, the temperature falls at once ; and inasmuch as tlie air within is already saturated, and since the lowering of the temperature of a saturated atmosphere is accompanied by con- densation of part of its moisture, such a condensation occurs within the flask, and is manifested by the formation of a distinct haze which fills the whole air space. If next we restore the original pressure by read- mitting sufficient air to abolish the partial vacuum, the mist disappears instantly. The production and dissipation of the mist cloud may be repeated indefinitely so long as nothing is done to remove the dust from the air ; but if we wash the air thoroughly by shaking the fiask vigor- ously for a few minutes, and then repeat the experiment, no visible mist is produced. CARBON MONOXIDE, ETC. Other matters found in air include, under certain conditions, traces of sulphuretted hydrogen, sulphurous, sulphuric, and hydrochloric acids, carbon disulphide from rubber factories, marsh gas, carbon monoxide from illuminating gas, fumes of zinc, arsenic, and phosphorus, organic vapors from offensive trades, and other gaseous and solid matters too numerous to mention. The most important of these is carbon monoxide, a very powerful poison, often present in the air of mhabited rooms from leaking gas pipes, imperfect combustion of illuminating gas, and defects in heating apparatus fed with coal. It is yielded in great abundance by burning charcoal, and is given off in small amomits from stoves of cast iron, which material in a red-hot condition absorbs it in considerable amounts from burning coal. This was noticed first by Dr. Garret,^ of Chambery, who described an outbreak of sickness traced by him to this cause. Later, this property of cast iron was established beyond a doubt by others. Another by no means insignificant source is burning tobacco, 1 gram of which, according to Grehant,^ yields 82 cc. of the gas. Its presence in the air of rooms in which smoking is carried on was illus- trated by Kunkel,'^ in 1888, before a society of scientists, by exposing a small amount of blood solution to two puffs of tobacco smoke, and ^ Comptes rendns, 1865, p. 793. ' Annales d'Hygiene publiqiie, 1879, p. 115. * Sitzungsbericht der physikalisch-medicinische Gesellschaft zu Wiirzburg, 1888, p. 89. CARJiON MONOXlDi:, I'JTC. 281 (IcmoiiHtniiiii}!,' (Ii(! uhsoi'idion of" (lie ^:is Wy iiicatiH «»(' tlif; HpoctrOHC^^JK!. Tlic, (iiosi iiii|)<)il;irit, ,s(»iir<',(' <»(' nil is illiMtiiii:i(iii;r p-is, wliicli r/)ntiiin8 ii, ill Viiryiii"!,' nnioiiiits, .■iccordiiij.'; to its mode ol" iii;iiiiif':i<'tiin'. Under ordiiiiiry (M)iiditioiis, I lie icnkn^'c oI'^.'ih IVuin I he iimins into (Ik- soil arieak;i;;«- oer-nrs from irn- pcrfeet joints, liuilty eoeks, and corroded iron pipes. I'>e-i. that (hie to k!akag(!, we liiixc to reckon with th:il due to irnperleet eoinhiistioti. WhiU> an Ar^Miid or otiiei- liurner net iiifr normally ^Ivch oil' no trar^; of (yirl)on monoxide, a certain pro|)ortion of the jthh will escape oxida- tion and min^l(! with tlu; air of the room toc;etlier with other impuri- ties, if the gas supply is not properly reguliited. The use of j^s stoves is responsihle for moi-e or less contamination due to imperfect combustion, for when a cold ohject is put into the flame, the latter is cooled, and part of its carbon inonoxid(' is given off as such. Imper- fect combnstion of kerosene is still another source which should not be overlooked, for a smoking lamp exerts a very decided influence on the respirability of the air of a room, aside from the discomfort ciiused by the ])articles of soot. Less than 0.25 per cent, by volume in the air will cause poisoning, and but 1 percent, is rapidly fatal to animal life, owing to the fact that it unites very readily with the hiEmoglobin of the blood cftrpuscles, forming a stable chemical compound, carboxyhaemoglobin, which will neither take up and carry ox}'gen to the tissues nor jiromote the elim- ination of carbon dioxide. As a consequence, asjihyxia occurs. In fatal cases of poisoning, carbon monoxide produces a rapid i)ar- enchymatous degeneration of the liver, kidneys, spleen, and heart. Carbon monoxide has been proved by L. de Saint ]Martin * to be present in minute amounts in the l)lood of animals living in cities. Nicloux * has gone fiirther, and demonstrated its existence in that of animals in the country, and, indeed, in about the same amounts (0.16 volume per cent.). Nicloux finds by experiment that it is not derived from the air, but is develojied directly in the system, and that its amount is diminished by bringing about slight asphyxiation. Potain and Drouin ■' have shown that, at ordinary temperatures, it is oxidized gradually to carbon dioxide. Contamination of the air of dwellings with gas from leaking street mains is quite common, and fatal results are not infrequent, the gas travelling through the soil lV)r considerable distances and being cb-awn up through cellars by the force of aspiration brought into }ilay by the difference between internal and external temperatures. jNIany cases of ' Ueber die Vergiftiing niit Leuchtgas. Xord und Sud, JanuarT, 1SS4. * Deutsche YierteljahiWoluift fiir otl'entliche Gesundheitspflege, X^"!!., 1885, p. 309. * Comptes rendus, CXXVI., p. 1036. * Ibidem, CXXVI., pp. 1526, 1595. * Ibidem, CXXVI., p. 938. 282 ATR. fatal ]i()isouing have been recorded in which the gas was aspirated through the soil for more than a luuulred feet. Such accidents are naturally more likely to occur in streets which, hcini; well ]>aved, present an obstacle to the escape of tiie gas upward. Tiic odorous constituents of the gas serve a very useful ]nir])ose in ])oiutiiig out the danger, but sometimes they arc held l)ack by the t'artli and cannot per- form that office. Dr. J. S. Haldane has pointed out that air vitiated by gas combus- tion to such an extent as to show 30 parts of CO^ in 10,000 will con- tain about 1 part of SO2 per 500,000, and that this amount is suffi- cient to cause marked discomfort. The air of a room lighted with oil was iu)t unpleasant, except for the heat, when the CO^ content rose to 75 ; but when gas was burned it was distinctly unpleasant when the CO, rose to 40 "in 10,000. " SEWER GAS." Another impurity is what commonly but inijiroperly is called ''sewer gas." This is simply sewer air which may be more or less foul by reason of containing the emanations of sewage matters. Its chemical composition depends upon the extent to which the gases of decomposi- tion are generated, and upon the rate of ventilation. It may be almost as pure as the outside air ; it may be as rich in carbon dioxide as the air of badly ventilated rooms ; and it may be much worse. From 10 to 30 volumes of CO^ in 10,000 are found quite commonly. Dr. W. J. Russell found as high as 51 volumes in 10,000 in the air of one of the London sewers, and Letheby as high as 53.2 in that of another, while in an nnventilated sewer in Paris as high as 340 volumes have been reported. Sulphuretted hydrogen and ammonium sulphide are ordinarily present in small amounts or mere traces, and may be wholly al)sent ; but in old nnventilated sewers, they may be present in notable amounts. The highest recorded, 299 volumes in 10,000, was found by Parent-Dnchatelet in an old choked sewer in Paris. Marsh gas, ammonia and compound ammonias, and other gaseous products of de- composition of organic matter, may be present in variable amounts, according to circumstances. Sewer air contains micro-organisms and animal and vegetable debris, just as does the outer air ; but, as a matter of fact, the number of bacteria is invariably small, and they are often wholly absent. This was shown first in 1883 by Miquel, whose results have been corrob- orated by those of a number of other investigators, including Carnelly and Haldane, Laws and Andrews, and Percy Frankland. The first mentioned conducted a most elaborate chemical and bacteriological ex- amination of sewer air, and proved that from both points of view it compares favorably Avith the air of schools and small dwellings, and that l)acteriologically it is, indeed, far superior. It contains fewer organisms than the air of the streets above or of any kind of dwelling, "si':ivi':n c-as." 283 and HlicJi iis Jtrc pi-csciii. conic ciilircly or chiefly f'roin (lie oiili r nir, ;iii^c-|»linMl)iiiLr tli:iii liv uell-liuilt sewers. It is asserted eonunonly (Jial- the inlmlntion ol".-in;ill amounts of this air will produce he;ir means of infection l)einestive tract, and excrcmentitious matters depositetl on unclean clothing-. In addition to these, it has been asserted that other matters of a poisonous character are given ofl' in the process of respiration, which matters will be referred to later on in the discussion of the effects of impure air on hetdth. That the air of inhabited confined s])aees may contain organic animal matter, is appar- ent to the senses when one enters such an atmosphere from one not thus contaminated. Effects of Vitiated Air. The effects of foul air on the system are of great im^^ortance, and vaiy in degree within very wide limits. For proper aeration of the blood, it is necessary that the oxygen of the air shall be present in the normal proportion in the free state, and not in chemical union with carbon as a ^vaste product. Farther, it is necessary for tlie proj^cr ex- cretion of the carbon dioxide of the blood that the difference in the tension of that gas in the air and of that in the blood shall be as wide as possible ; that is to say, the less the amount of carbon dioxide in the inspired air, the greater the facility with which the blood can dis- ensrao-e that which it carries to the lungs. Anv interference with this most important function of the body must have an injurious effect on the general health, and it is accepted generally that impurity of the air is, without doubt, the most important of the predisposing causes of disease. It is well known that, other conditions being equal, in ])roportion as a people are drawn to employments indoors, the disease-rate and death- rate are increased. This is particularly true as regards phthisis, which is preeminently associated with overcrowding. Overcrowding means the association of two or more jicojile in a space so confined as to preclude the adnn'ssion of a. constant supply of fresh air sufficient in amount to maintain a ]iroper dilution of their excretoiy products and a normal su])])ly of free oxygen. It was recog- nized long ago as a most important factor in the ])roduction of a high death-rate among occupants of crowded jails, barracks, and hospitals; and experience has demonstrated repeatedly that increase in space allowance is followed always by decrease in sickness- and death-rates. At one time, for example, the English army averaged 11.9 deaths per ICFFKCTS OF VITI.\TFI> MIL 287 1, ()()() incii ;iiiiiii:ill\', (Voiii |tlil lilsis iilotic ; inoif cflificnt Icirnick \«'ri- (,iliiii<^)ii !i-ii(l iiici-(';is(' (»r ;iAM'r;i|;c :iif s|»;i(:f' r;iii-((| iiiiiiii(|i;i(c iinprovf- iiionl., ;ui(l Uic |tlilliiHis-r;iU! ('ell ^rMdiuilly to \ /l [m i- I, Odd. '||ic HiUiK! ^'('iKirMl I'csnll. Ii;is hccii oltscrxcl in the ;iniil<- oC l-'niiicc, ltii>.-i;i, (}(!nn;iny, ;iii(l rK'lt;iiiin. Wli;i( is (rue of ovcrci'owdiii;^ ;i|i|ilii'- nul ;i|(.iic to liiiin.iii hciiij^^, l)ll(, (() ;iiiilii;ils ;is well, jiikI i(. is ;i well- l< now n liicl tii;il crowrlcd hliihlcs show lii<;'li iiiorlalily Minoiijjj cows iind horses. It has such a n-rnark- ilbhi iiifhic.iicc on (■<;•;;:; |)ro(hicli«»ii and }i;fowth of lowl-^ that |»r"a'-lir-al poullrynicii aiH^ cxcccdinnly carcrul on this point. The ininu'(lia((! cITccIs of inhalation oC inipni-c air arc di-t'ornloit and (>p|)i-cssion, which may anionnt to headache, ;ht in a space of less tiian 5,900 cubic feet, with two small windows in one side. Within an hour, all broke out in a [)rofuse sweat, antl were tortured with thirst and dillicult breathing ; in three and a half hours, a majority were delirious, and when the place was opened in the morning-, 123 of the prisoners were found dead. In the case of the Loiuloiido-ri/, which, in December, 1.S4.S, lett Sligo for Liverpool and ran into a storm, 200 steerage passengers were con- lined over night in a space 18 by 11 by 7 feet, with no means of ven- tilation. In the morning, when they were released, it was found that over 70 had expired. In the other extreme case, that at Ansterlitz, 300 ca)itured soldiers were confined in a small cellar, and within a few hoiu's all l)ut 40 were dead. To what one or more conditions of impure air are the ordinary effects due? We have seen that COo is in itself not an active poison, and that its action is to interfere with the proper oxygenation of the blood within the lungs. The aqueous vapor of respiration and from the skin, and that produced in the combustion of illuminating material, constitutes an important part of a vitiated atmosphere, and is respon- sible for at least a part of the discomfort produced ; but it is also true that a deficiency in watery vajxir in the air of well- ventilated rooms has equal or greater disadvantages, as will appear in the consideration of Ventilation. 288 AIR. Concerning the effect of usual amounts of ordinary dust in in- habited rooms, there is little to be said. The micro-organisms, most of which are non-pathogenic, vary in number with eihciency of ven- tilation. In pure air, the bacteria and moulds approximate each other in number ; but in vitiated air, the bacteria increase in number, while the moulds are much less affected. The experiments of Carnelly, Haldane, and Anderson showed a progressive increase in both bacteria and moulds with diminished ventilation. Thus, Character of air space. Number organisms in 10 L. air. Ratio of moulds to Moulds. Bacteria. bacteria. External air 2 4 22 12 6 85 430 580 1:3 1:21 1:20 1:48 2-rooiued iiouses l-roomed houses The increase in bacteria is not due to respiration, though a diminu- tion in their number might be thus explained ; for the great majority of inhaled bacteria are filtered out by the nose, and the expired air is almost completely free from germs, although they may be thrown out in the act of coughing or sneezing. Investigation thus far has not proved that the bacteria of infection are commonly introduced into the system through the medium of re- spired air. As has been mentioned, it is held by many that the effects of vitiated air are not due to carbon dioxide, but to the organic matters and aqueous vapor given off by the lungs and skin, and that these are estimated conveniently by determining the amount of carbon dioxide with which they are discharged. It is said also that, while considerable carbon dioxide escapes even under the most imperfect system of ventilation, the organic matters and watery vapor do not so readily pass out, but are deposited on walls, furniture, hangings, and clothing, where they putrefy and become offensive. As proof of this, is cited the fact that a room in which a person has slept without adequate ventilation has an unpleasant smell in the morning, and that this persists even after prolonged airing. Brown-Sequard and d' Arson val, in 1888, obtained from condensa- tion of the aqueous vapor of men and animals a liquid which, injected into rabbits, caused death with greater or less rapidity, according to the size of the dose. They believed the toxic element to be of the nature of a volatile alkaloid, and that it was exhaled dissolved in the aqueous vapor of the breath. In the same year, Wurtz, reporting a similar research, claimed to have found a toxic substance. Merkel/ in 1892, claimed to have obtained positive results, and con- cluded that res])ired air from persons in health contains a minute quan- tity of a volatile organic base, which is poisonous when free, but innoc- ' Arcliiv fiir Hygiene, XV., p. 1, EFFEVTfi OF VITI A '!'/•: 1) Afll. 280 U0U8 after vxmi-M'.i witli uii swiid. Dr. Sivi(;r;i(<» ' ctMcc.U'A the ;u|ii(;onH vapor of llic hi'cntli ol" pcrHoriH Hiilloriiijr from discuses of r<:sj)iralioii, hoili willi iiikI vvillioiil Ccv*'!-, oC pcrsoiiH with no r(!S|)iratory (liHwiHO, but willi f(!V('-r, ;ui;lish, working; alon<>; the same lines, but with extra precautions to cx(^lude matters from the nose and mouth, have failed to obtain toxic ctfects from the condensed vapor ; others have demonstrated that the lungs exhale no organic matter except in minute amounts, and that these have no poisonous influence. Arloing pursued the subject further, in the belief that the constitu- ents of the sweat are concerned in the harmfid effects. Pie soaked the underclothes of a man who had spent a long evening in dancing, and injected the watery extract into dogs and rabbits. From the fact that the animals showed various evidence of intoxication and died he concluded that sweat is toxic. Experiments in the author's laboratory, however, with sweat obtained directly from well-scrubbed forearms and injected in considerable amounts into rabbits and other animals yielded negative results. Sweat vaporized in small confined spaces was equally innocent of harmful results to men and animals exposed thereto. At present the weight of evidence leads to the con- clusion that the injurious action of vitiated air is due to the dimi- nution of oxygen and to the increase of carbon dioxide, both of which factors, alone or together, interfere with the intake of oxygen and the excretion of carbon dioxide from the lungs. Yet, dmiinution in oxygen, which even in very crowded rooms does not ]iroceed very far, is met by increase in the respiratory function, which, however, cannot increase the difference between the tension of the carbon dioxide of the air and of the blood. Not even in very imperfectly ventilated mines does the oxygen fall much below 20 j)er cent, by volume, and thus we see that the whole range of fluctuation in the oxygen of pure and of very foul air is but little more than 1 volume per cent. Smith and Haldane^ have shown that in a leaden chamber containing ^ Archives Italiennes de Bioloijie, 1895. ' Avohiv fiir Hyiiiene, XXXVIII. (1900), p. 1. •■' Journal of Pathology and Bacteriology, I., 1892. 19 290 AfR •A\v which had suifered but slight (lii)iiiiiitiiiii in oxygen, but Avhich ODiitained 8S4 ])arts of carbon dioxide in 10,(K)(>, two men suffered from headache imnu'thati'ly on entering. As a rule, vitiated air is associated witli higli temperature and satu- ration with aqueous vapor, whicli hitter interferes with evaporation from the skin. Less often it is associated with h)\v tem])erature, and with this condition comes an increased demand for oxygen to meet the requirements of the oxidation ])rocesses. It seems probable that where the carbon dioxide is not jircsent in any great excess, and the oxygen is not markedly tleiicient, the conclusion arrived at by Drs. Weir Mitchell, Billings, and Bergey is true ; namely, that tlie discomfort suffered is due largely and chiefly to heat and dis- agreeable odors arising from tlie occupants in various ways : from bad breath, unclean skin, imcleau clothes, sweat, and gases from the bowels. Such may induce very disagreeable sensations, amounting even to nausea, in those who are not habituated to such influences ; but, on the other hand, those who are accustomed to such air notice no discomfort. Disagreeable smells do not act directly as a cause of speciflc disease, but appear to have an influence on the appetite, and hence on the gen- eral well-being of persons not accustomed to them. Much is due also to the imagination ; a disagreeable smell from a source known to be clean (chemicals, for instance) has not ordinarily as much influence as another of equally offensive character sup]>osed to be from filth. It seems probable also that there is much to learn concerning the real effects of disagreeable smells, and that they may be more extensive than we now commonly believe ; but in order to determine this, we sliall need methods which Avill reveal the nature of the odoriferous substances and make their isolation possible. Other causes of discomfort may be sought for in the presence of traces of carbon monoxide from heating apparatus or incomplete com- bustion of illuminating gas, and in excessive dryness of the air due to furnace or steam heat. It should not be overlooked that impure air may affect the vitality aud bactericidal power of the cells of the air-passages and of the ali- mentary tract, and thus lessen the power to resist the action of infective material. The Air as a Carrier of Infection. On the agency of air in spreading infectious matter, nuich has been said and written, and much careful research has been conducted, but the conclusions reached are by no means in agreement or conclusive. It is conceded generally that pathogenic organisms in the air are ad- herent to particles of dust of various kinds, and that their retention of virulence depends upon the amount of hygroscopic moisture Avith which they are associated. The conditions favorable to their continuance as living organisms are naturally more likely to oljtaiji in indoor air, with imperfect ventilation, than in the outer air, where they are diluted and blown about and exposed to the disinfectant action of the direct Tlfh: Mil AS A dAIUUHIL OF I NFF/mON. 291 r.'iys (>(' lJi(^ sun. Iiidnors or oiiI(" piilmonary (nln rcnlo>i- fliron^li the air, it slionld \n\ said (liali while (here can he no U(;hner has Cound //. /ii/xrcii/osis in an acli\c .'-(a(e in (he «his( of U room a year aCler (he dealh oC ils occii|i;inl Inini the disease, (i. C'Ornet' denions(raie(l i(s |»resen(;e in more than a third of 1 17 saiii|»l<'H of (Inst (!oll(H'-l('d in lios|)itals and other |iiil»lic iii-( il nl inn-^ ;iiid in |)rivat<; honses inhahiied hy |)hthisical |)ersons, and sn(;ceeded later in prodncinj^ the disease in K! out of 18 gtiinea-|)igs exposed to air containing dust from dried tuberculous sputum. Some of the animals were placed 8 inches from a o^lass vessel containinc^ dried pulverized sputum from an advanced ease; others were i)laced on shelves 8 to 28 inches from the floor of a. room, on the carpet of which, sputum, mixed with dust, had been spread and dried and, at the end of two days, stirred u[) by sweeping ; others were allowed to stay in the room without disturbance of the dust. Klein obtained positive results with g;uinea-})igs ])laeed in (he venti- lating shaft of a consumptives' hospital ; but Hei'on - obtained but 2.7 per cent, of positive results in 74 guinea-pigs inoculated with dust from the ventilating shaft of the London Hospital for Diseases of the Chest ; and Kirchner'' got but 1 positive result out of 16 pigs inoculated with the dust from a military hospital. Fliigge, on the other hand, was wholly unsuccessful in inducing the disease in guinea-pigs exposed to such dust ; and concluded that the transmission from one person to another is chiefly by means of the finest droplets thrown into the air in sj>eaking, coughing, and sneezing. From later experiments, conducted under his supervision by Laschtschenko, Heymann, Sticher, and Beninde,^ he concluded that in rooms in which tuberculous sputum is dried on the floor or other jilaces, and where the air is filled with coarse dust through dry cleaning and air currents, or, as in railway ears, bv continual mechanical jarring, infection may arise ; and that, under the.se conditions, long-continued exposure otters a certain degree of probabilitv of infection. Therefore, dry cleaning is to be avoided in rooms in which consumptives ai'c employed with others, and the rooms should not be occupied so long as the air is {perceptibly dusty. The great pos- sibility of infection through matters thrown ott* in coughing and snee/-- ^ Zeitsclirii't fiir Hygeine, V., p. 191. '■' Tlie Lancet, January G, 1894. ^ Zeitschrit't fiir Hvsiiene und Infectionskrankheiteu, XIX., p. 153. * Ibideni, XXX., p.l07. 292 AIR. iug is insisted upon as of paramount importance. This dauo-er is to be prevented bv requiring the jierson eoughing to hold a handkerehief or the hand before the mouth during the aet, and by the avoidance on the part of others of approaching within a meter. Answering Fliigge, Cornet ' contends that the number of bacilli thrown into the air during the act of coughing must be extremely small. He caused 18 consumptives to hold dishes before the mouth while coughing, and obtained 2 positive results therefrom on inoculation into guinea-pigs ; repeating the test with 1 5 others, he got none ; but Heymann - was more successful, for glass plates exposed in the imme- diate vicinity of coughing consumptives, confined for an hour and a half in a glass cabinet of three cubic meters' capacity, were proved to have become contaminated by the specific organism. The plates were rubbed up with small amounts of broth, wdiich was then injected intraperitoneally into guinea-pigs, mostly with positive results. Experiments conducted by Ivoniger^ confirm Fliigge in his estimate of the danger of transmission by droplets. In order to give the ex- pelled droplets a character which would admit of their being traced, he rinsed his mouth with liquid rich in B. prodigiosus or B. mycoides, or with very dilute caustic soda, and, in order to trace them, he exposed Petri dishes and glass plates coated with phenolphthalein, which agent, turning pink in contact with an alkali, Avould show not only the number of droplets, but their size as well. It was found that no drop- lets are thrown out in ordinary exhalation nor in vowel formation, but with consonants, as t, k, and p, the number is very great, and is largely dependent upon the amount of force with which the air under pressure in the mouth cavity is released in their formation, and, therefore, upon the manner of pronouncing. Loudness and rapidity of speech have but little influence ; whispering m.ay, indeed, under some conditions, cause a greater number of droplets than loud speech. Even wdth sub- dued speech and a quiet atmosphere, it was found that the organisms expelled reached the most distant parts of the room, which was more than 20 feet in width, and in all directions. They were found to remain in suspension in the air not longer than an hour, and it was noticed that they fell upon the plates in groups, sometimes as many as 40 close together, which suggests that they fall not as dry dust particles, but that the droplets themselves, with their contained or adherent organisms, are deposited. In coughing and sneezing, more droplets are expelled than in speaking, and they are projected to a greater dis- tance, because of the greater force engaged. The precautions recom- mended apply not alone in tuberculosis, but also in diphtheria, wdioop- ing-cough, and other diseases in which the respective specific organisms are ff)und in the air-passages. Hutchison * found that bacteria, sprayed in minute droplets upon ^ Berliner klinische Wochenschrift, May 13, 1899. * Zeitschrift fiir Hygiene und Infectionskiunkheiten, XXXVIII. (1901), p. 21. ' Ibidem, XXXIV. (1900), p. 119. * Ibidem, XXXVI. (1901), p. 223. Till': A in AS! A dAlilLll'Jl 0/-' ISl'KdTIOS. 293 ohjccts, |)(!risli in w. hIioH, IJiiic, the iiuiiii (iidor in I li< ir l<'. I lie diploeoe(^i, in ti^(!ii(!raJ, hear diyiiit;' loi- a, lon;hly im|)robal)le. (Tcrmano's work with the plague bacillus confirms the results an- nounced by Kitasato and Wilm. This orported by Buchanan,' who argues from the fact that, of 60 cases which came under his observation, 57 were in men who followed occu[iati(^ns in which they were exposed to dust, the specific organisms are thus conveyed. Dr. Max Neisser,' working in the same line as Germauo, with au apparatus of his own design, which maintains a constant aspiration current of dusty infected air, disagrees as to the pueumococcus, inas- much as, while mice, inoculated with infected dust, dial from the in- fectiou without exception, 24 others, inoculated with the dust af\er it had beeu sent through the apparatus in a current of air, gave abso- lutely negative results. His experiments with various organisms led him to the conclusion that dust infection is impossible with the organ- isms of diphtheria, typhoitl fever, cholera, plague, and pneumonia, but 1 Britisli ■NFedioal Jouni;i1, Soptomlvr 14. 1901. ^ Zeitsoiuil't lur Hygiene uiul Infeotiimskrankheiten, XXVI., p. 175. 296 ATR. possible witli Siaphylococcus pyogenes aureus, J?, pyocyaneus, B. an- thracis, B. tuberculosis, and ineninoxieoccu.s. Neisser's conclusion.^, .'^o far a.^^ t])cy relate to diphtheria, are opposed to the results obtained by Kichardiere and Tollemer/ who made a series of examinations of the air of diphtheria wards of the Hoj^ital Trons- seau. In one set of experiments, the wards had not been disinfected for several weeks ; and in another, the examinations were made after disinfection had been carried out. The results showed that active diphtheria bacilli were present in the air which had not undergone disinfection. The bacteriological tests were controlled by inoculation cxpenmcuts with animals. A\'ith rcg-ard to the possibility of spreading cholera germs through the agency of moving air, Dr. N. William ^ has reported that, while that means has been regarded as most favorable, in actual experiment it foils. Mixed with dry dust, the germs live but a short time, and perish more quickly when a current of air is conducted through the dust. AVheu the dust is distributed through large volumes of air, the germs die rapidly, and when the impregnated dust is let fall upon a suitable culture, only a very small proportion of living organisms can be found. In other words, cholera germs, adherent to du.st particles floating in and moved about by air, do not retain their activity for any length of time nor through any considerable distance. The experiments of Honsell ^ indicate that the cholera organism finds no favoring conditions for its passage into the air from its situation in privy vaults. The subject of danger of cholera infection by dust from baled rags was considered thoroughly at the Dresden Cholera Conference, and it was found impossible then to quote a single case in which infection could be traced to this source. According to Dr. E. W. Hope,* atmospheric dust is largely respon- sible for the spread of infantile diarrhoea in cities and large towns, where, from unavoidable causes, the air becomes more or less laden with filth. He presents evidence of the association of rainfall and its attendant cleansing of the atmosphere with diminished mortality from choleraic diarrhoea, as follows : Average rainfall Annual average of deaths Period. June to Conditions. from diarrhoea during September. third quarter of year. 6 years 13.8 inches Average wet sum- mers. 373 14 " 10.9 " Average dry sum- mers. 573 Extreme years. 1891 16.0 " Wettest .summer. 203 1895 7.7 " Driest summer. 819 1 Gazette des Maladies infantiles, No. 10, 1899. ^ Zeitschrift fiir Hygiene and Infectionskrankheiten, XV. (1893), p. 166. ^ Arbeiten aus dera patholog-anatomischen Institut zu Tiibingen, 1896. ♦ Public Health, .July, 1899. EXAMINATION OF A I II. 297 Influence of Fog. Dust ;ui(l nioisliin! (,();^( oilier in llif I'liin nC lo^' ;ifr<'t tlic lic'ilfli of \',iY\!\\ (ioiiiinnnilics in ii, in.-irkcd decree. In ;i still iiir nearly or coni- pUiLoly sjitiiraidd willi a(|M('()iis vjipor and rontaiiiin^ ordinary dnst and smoko, a fail in l(!ni|)('ia(iir(' <;iiihoh (3a(!li particle of diiHt and Koot U) heoomc tlu; nn(!!(!ii,s of a, niiinilc! dropK^f of f.ondc.nHcd inoJHtnn!. TlH^ci countloHH droplets in a slati; of snspcnsion form a inon- or JesK d('tiH(! I)laiik(^t of fo^, wliicJi impedes dispersion of the impurities jrivr-n off by natural pro(;css{!S and as products of (;ond)Ustion. Wliile r»rdinary country and seiishon^ fo^s ai'c; not known to cxort d(!let(Tions eU'ectw, in smoky cities, lik(! London, tlu; easi^ is fpiit(! diff(;r0 Provide; (iMc.li vvilJi w \'\\r\\[\y liMin^ i-iiMxr sloppci- willi (wo jHTforatioiiH, tliroii^li wlii<'li ;i,r(! iiiHcrle^d two piece- oC <^\:\-r liihin^ hciil. at a right angl(!. One of (Ji(!M(! numlldH In llie liolldlil of I he |l;i.-|<, ;i|ul HrTVCH OH ail inliit ; tlu; o(Ji(!i' cxIcikIs only a short (h'slunc*; helow th(! hlo|»|»cr, and S(!i"V((S as an onllel. I' ill (he fhisks wi(h Kni;dl pi<'cc.s (»r |iurnie«; wlii(;h have Ixen lie.iled lo ;i lii^jli lenipeiiil nie over ;i |'>nn-eti hnrncr, (h'oj)ped while hot into eoiieenlraled snl|»hiirie, acid, I'enioveti llie|-c(roin, and (jnicliee,(; of rnhhcr tnhinu;, (he inh'l o(" one joinin}^ (he oii(le( of the (tthcr. Tlicy arc; then wei<;lied. The ll;isl< willi the free onllct tuh(; Ih MOW t() be <;onn('e(,('d wi(h :in ;is|>ira,(or, hy means of which from 20 to '>() lit<;r.s of air ar(! drawn (hronnh. As (he air conu^s in contact \vi(h th(! jinmico satnra(cd wi(li snlphuric acid, its mois(nrc is ahsorhcd and retained. >\t the! cxj)iration of the aspiradng procicss, the flasks are diseoimectod from the aspirator and again wcij^hed. Tiic increa.se in weight repre.sents the amonnt of moistnre in the vohnne of" air used. The a[)paratu8 is shown in J*'i<;'. ! I . Know- ing the tc^mperatnre of the air, one can then easily determine the relative humidity by refer- ence to the tabk^ beh)w, which shows the maxi- mum humidity possibleat different temperatures. TAnr.K OF MAXIMUM WATER CAPACITY FOR TEN LITERS OF AIR. Fio. 12. Tempera- ture centi- grade. Corre- sponding degrees F. Grams. Tempera- ture centi- grade. Corre- sponding degrees K. Grams. —10 14.Q 0.021 13 55.4 0.113 — 8 17.6 0.027 14 57.2 0.120 — 6 21.2 0.032 15 59.0 0.128 — 4 24^8 0.038 16 60.8 0.136 — 2 28.4 0.044 17 62.6 0.145 32.0 0.049 18 64.4 0.151 1 33.8 0.052 19 66.2 0.162 2 35.fi 0.056 20 68.0 0.172 3 37.4 0.060 21 69.8 0.182 4 39.2 0.064 22 71.6 0.193 5 41.0 0.068 23 73.4 0.204 6 42.8 0.073 24 75.2 0.215 7 44.6 0.077 25 77.0 0.229 8 46.4 0.081 26 78.8 0.242 9 48.2 0.088 27 80.6 0.256 10 50.0 0.094 28 82.4 0.270 11 51.8 0.100 29 84.2 0.286 12 53.6 0.106 30 86.0 0.301 Determination of Relative Humidity by the wet and dry Thermometer Bulbs. This instru- ment, which is kno\vi\ also as the psychrom- eter, consists of a pair of accurate thermoni- eters on an upright support. The bulb (^f one is free ; that of the other is covered with a rsychrometor. 300 AIE. layer of muslin kept moistened by means of a piece of wickiug which dips into a small vessel of water beneath. (See Fig. 12.) In a satu- rated atmosphere, no evaporation can occur from the wet nuislin ; but in one not saturated, the process goes on with varying rapidity. Evap- oration is a process which requires heat and causes a lowering of the temperature of the moist surface ; the more rapid its rate, the greater the abstraction of heat. The drier the atmos])here, the greater the rate of evaporation, and, therefore, the greater the fall in temperature. If the instrument is placed in a saturated atmosphere, the two thermom- eters will give the same readings ; but in one not saturated, the wet thermometer will fall gradually until the temperature of the surface of its bulb is nearly as low as that of the dew-point ; that is, falls to that point at which air at the indicated temperature is so saturated that a farther lowering would be followed by condensation of moisture. As a matter of fact, the wet thermometer does not fall so far in a quiet air, since its bulb becomes surrounded by a layer of stagnant saturated air, and receives more or less heat from the surrounding warmer atmosphere. Again, in a saturated atmosphere, the wet thermometer may stand slightly higher than the dry one, owing to the fact that its covering protects it from loss of heat by radiation. GLAISHEE'S TABLE. Reading of Reading of Reading of dry bulb Factor. dry bulb Factor. dry bulb Factor. thermometer. thermometer. thermometer. 10 8.78 41 2.26 71 1.76 11 8.78 42 2.23 72 1.75 12 8.78 43 2.20 73 1.74 13 8.77 44 2.18 74 1.73 14 8.76 45 2.16 75 1.72 15 8.75 46 2.14 76 1.71 16 8.70 47 2.12 77 1.70 17 8.62 48 2.10 78 1.69 18 8.50 49 2.08 79 1.69 19 8.34 50 2.06 80 1.68 20 8.14 51 2.04 81 1.68 21 7.88 52 2.02 82 1.67 22 7.60 53 2.00 83 1.67 23 7.28 54 1.98 84 1.66 24 6.92 55 1.96 85 1.65 25 6.53 56 1.94 86 1.65 26 6.08 57 1.92 87 1.64 27 5.61 58 1.90 88 1.64 28 5.12 59 1.89 89 1.63 29 4.63 60 1.88 90 1.63 30 4.15 61 1.87 91 1.62 31 3.60 62 1.86 92 1.62 32 3.32 63 1.85 93 1.61 33 3.01 64 1.83 94 1.60 34 2.77 65 1.82 95 1.60 35 2.60 66 1.81 96 1.59 36 2.50 67 1.80 97 1.59 37 2.42 68 1.79 98 1.58 38 2.36 69 1.78 99 1.58 39 2.32 70 1.77 100 1.57 40 2.29 EXAMINATION OF A 1 11. :;oi V\)V llio piirpoHC! To?- wliicli il is inlcndid, tlic iii-fnirrKTit is cxpoHr-*! until Uk! WcI. llici'Kioiiictcr (■<';i,-;cs to full, ;iii00), tJic (|c\v-|»oiiit is cMsily <',;il(Miliit«'(l in llic f'ollow- \\\\r ni;inn(^r : MMlli|)ly tli<' (lill'crcnct! in llic two rcjulin^s hy tlir- liictor oppo.sitd tlu; (i(■ IJk' wcl bull). P].\;iiii|)l(', : liciidiiiKof (Irv l)iill. 72° Hi-.uWuir (.r w<"l, l.ull. m° I)i(IiTl oC ;ill, be Mi<';i-ni'e(| very e:i.re('ully. This may be done by lillinL; llnni with iee water and noting' the, number of ee. recpiired, oi' by dclciniinintr by nKsm.s of" plat- i'orni senJes sensitive to o i;'r:n)is the dillerenee between llnir wei^rjits empty a,nd lllled. It- is well to plnee ;i distinii'uishinLr number and tho tlj>;ures deuolinj:; its eapa('ity on eneh but lie, eiiher on ;i l;d)el, or, belter, by means of ;v wi'itinu,' diamond. When used, the bottle shonid be perfectly clean and dry. When it is neecssary to (imploy tli(; same bottle a_L;ain, lim<; beinjj^ an ol)jcct, the drying process is hastened very Jiuicli by wasliing first witli water, then with a little alcohol to remove the small amount of" water which will not drain away, and, tin;dly, \vith a little ether for the re- moval of the I'csiduuni of" alcohol. The small amount of adherent ether may then be removed by blowing a current of air into the bottle by means of a bellows. A number of tightly fitting rubber caps should be provided in place of corks or rubber stopiiers, though if these are not at hand, the latter may be used ; but note should be made of the volume of air which they displace when they are inserted. Solutions Required. — 1. Solution OF Bat{iu:m IIvDRATK. — Dissolve about 4.o grams of liarium hydrate and 0.5 of barium chloride in a liter of distilled water which ju-eviously has been boiled, in order to ex]iel any carbon dioxide which it may contain. It is well to prepare an amount suf- ficient for future needs, say 4 liters, and to keep it in a bottle such as is shown in Fig. 14. This is provided with a rubber stopper with two per- forations, through one of which a bent tube, reach- ing to the bottom, and intended for withdrawal of the reagent, is inserted. Through the umice soaked while hot in a strong solution of caustic potash. The delivery tube carries at it* outer Bottle for V>arium hydrate. 304 AIR. end a piece of closely fitting rubber tubing, which is kept closed by means of a pinehcock. In withdrawing the reagent for use, a 100 cc. pipette is inserted into the free end of the rubber tube, suction is applied, and the pinehcock is opened. AVhen the pipette is filled to the mark, the pressure is removed trom the })inclicock and the ])ipette released. As the reagent is withdrawn, air fiows in through the other opening, and is robbed of its carbon dioxide by contact with the caustic potash with which the pumice has been charged. This reagent is used for the absorption of the carbon dioxide contained in the sample of air under examination. The reaction is expressed by the following formula : BaO^H, +CO,=BaC03+H20. The function of the barium chloride is explained below. 2. Standard Solution of Oxalic Acid. — Dissolve 2.808 grams of pure oxalic acid in a liter of distilled water. One cc. of this solu- tion is equivalent to 0.5 cc. of carbon dioxide ; that is to say, will neutralize the same amount of barium hydrate as will combine with carbon dioxide to form barium carbonate. 3. Solution of Phenolphthalein. — Dissolve 0.5 gram of pheuolphthalein in 100 cc. of alcohol. This solution is used as an " indicator " of alkalinity. Process of Analysis. — The process of analysis depends upon the fact that when a volume of the barium hydrate solution is brought into contact with carbon dioxide, its alkalinity is diminished by the forma- tion of barium carbonate, which is a neutral body. The greater the amount of carbon dioxide to which it is exposed, the greater will be the reduction of its alkaline strength. A preliminary determination of the amount of oxalic acid solution which 100 cc. of the reagent will neutralize is made by titrating 25 cc. contained in an Erlenmeyer flask and colored by means of a few drops of the phenolphthalein solution, and multiplying the result by 4. After the reagent has been sub- jected to the influence of the gas in the air sample, a similar determin- ation is made. The difference between the two results, divided by 2, indicates the number of cc. of carbon dioxide jjresent in the amount of air employed. The sample of air is obtained in the following manner : One of the bottles above mentioned is placed in the situation from which the air is to be obtained, and its air content is displaced by means of a bellows provided at its outlet with a rubber tube of sufficient length to reach nearly or quite to the bottom. A half minute's pumping is sufficient to insure that the original air is replaced by that under observation. One is sometimes admonished to be careful not to breathe in the direc- tion of the mouth of the bottle, but this is an unnecessary precaution, since the current issuing from the bottle is much too powerful to admit of the entrance of any air except that propelled by the bellows. A much more and very necessary precaution to be observed is that the operator shall not allow his breath to reach the inlet holes of the bel- I'lXAMIiS'A'I'ION OF Alii. 305 loWH. Art(!ra li.'ilf nilniifc's |)iiiii|»iii^, llic riildxir r;i[» is Mflixcd, jiiid the l)()ttl(; iiiiiy lluin he (•,:i,n'i('<| to \\\<', l;il»(ii;itiii-y, or, l»(lt<'i-, (lie trciit- iiKiiil. <»(' tlic (;<>iil;i:iiic tiieopcJiing so made, the point of the I11I(m| |)ipette, and allowing its (contents to (h)W nnaided into the hotth'. 'i'he heginner will often in(;Iine inadver- tently to gain time, and assist the emptying of the |)ipette, by blowing into it, tiuireby vitiating his resnlts with the imj)nritie.s of his own respiration. As soon as the pipette is emptied, it is withdrawn and the edge of the cap is re|)laeed. The bottle is tlien shaken thoronghly for about ten minutes, eai'e being observed not to wet the eaj), since in that event some of the reagent may escape by capillary attraction. At the end of that time it may be assumed that all of the contained carbon dioxide has been brought into contact with and absorbed by the barium hydrate, which is then to be ])oured quickly from tlie bottle through a fairly large funnel into a glass-stoppered bottle of rather moiv- than 100 cc. capacity. The solution, which is now more or less turbid from the presence of barium carbonate, is allowed to stand until, through settling of this substance, the supernatant liquid is clear. Three successive portions of 25 cc. each are next to be withdrawn by means of a jiipette of the proper size, and, after addition of the indicator, titrated in Erlenmeyer flasks with the standard oxalic acid solution until the pink color caused by the former is made to disappear. So long as any color remains, one knows that barium still exists in the form of hydrate, and that the contents of the flask are still alkaline, for phenolphthalein gives a pink tinge only in the presence of the alkalies. When the pink color disappears, the process is finished, and the reading of the burette is noted. The three portions of 25 cc. each are titrated in turn, and the mean of the results is multi])lied by 4. The dittereuce between this product and the figure olitained in the pre- liminary test of the strength of the reagent, divided by 2, indicates the number of cc. of carbon dioxide in the volmne of air taken for analysis. In filling the 25 cc. pipette from the bottle containing the used reagent, great care should be observed not to stir up the sediment of barium carbonate. To perform the operation properly, it is necessarj' to insert the point of the pipette well below the surface, and to fiU it up to the mark, or just beyond it, by one iiuiuterrupted act of suction. If one stops to regain breiith, part of the liquid already within the 20 306 AIR. pipette will eseupe downward duriuij the interval with snfficient force to .stir up the sediment. When the pii)ette is filled, the point of the tongue should be api)lied to its U})i)er end, and the tip should then be withdrawn from the buttle. Then bv iilacinp- the end of the forelinu'er over the opennig- of the tip of the pipette, the escape of its contents is prevented, while the forefinger of the other hand is replacing the point of the tongue. The reason for such careful avoidance of stirring up the stHlimcnt is that the presence of barium carbonate introduces a slight eri-or in the titration. The slight excess of oxalic acid present when the eoh)r t)f the ])hein)l])hthalein is discharged attacks the sus- pended barium carbonate, forming barium oxalate and setting free the combined carbon dioxide. Thus : II^C^O^ + IkCOj = BaCjO^ + H,0 -|- CO,. The free carbon dioxide then attacks more of the carbonate and forms barium bicarbonate, ^\■hich, being soluble and of alkaline reaction, causes the pink color to reappear. /OH co/ >Ba =BaH,(C03)2. co/ ^OH The reason for adding barium chloride in making the barium hydrate solution is that most barium hydrate contains, in addition to small amounts of carbonate, traces either of caustic soda or of caustic potash. When either of these snbstances is brought into contact with barium chloride, mutual decomposition occurs, and we have as results barium hydrate and sodium (or potassium) chloride. If the impurity Mere disregarded, it would cause errors, as shown below. The barium hvdrate solution when titrated with oxalic acid would behave according to the following formula: BaO^H,, + BaCOs + 2NaOH + 2H,C,0, = BaCp^ + BaCOj + l^^atCfl^ -\- 4H,0 (Barium (Barium (Sodium (Oxalic (Barium (Sodium hydrate) carbonate) hydrate) acid) oxalate) oxalate) In practice a very slight excess of oxalic acid is also jiresent, and the reaction then proceeds still farther. The sodium oxalate attacks the barium carbonate, forming barium oxalate and sodium carbonate. Thus Na.CjO, + BaCOg = BaC.O^ + Na^COg. Next, the sodium carbonate neutralizes the traces of free oxalic acid, and any surplus causes a reappearance of the pink color and neces- sitates farther addition of oxalic acid. This causes the formation of more sodium oxalate, which in its turn attacks another portion of the barium carbonate, with the same results as before ; and so the cycle continues until the last trace of suspended carbonate is decomposed. If the hydrate contains no impurities, the addition of chloride is unnecessary. ICXAMINATION OF Mil. 307 Corrections. — In (i^iirin^j (lie rcsiills o(" the dch riniii.'ition, ciil.-iin (•,(>r'r(!(;(,i()iiH ;i,f(! iicccwsMry. I''ir.sl, tlic soliiinc uC llic. Ii;ii-iiiiii liydnito ii,S(!(l (100 cc.) iiiiisl, l)(! .Mill»tr;ii'l((| riom iIm' <;i|);icily (»f tlu! bottle, kImco i(,.s iii(;f()ressnre, tlu; tliermonieter anr CJUih d(;t!;i'e(; <'enti,a;ra(l(! aho\'e oi- below 0" ('., air expand- or fori- tracts 0.00o(5() bS of its volinne ; and this ligiire is known as the <;o- eflieicnt of expansion for eenlinradc? (U^grces. For each dej^rec Fahren- heit above or below '-Vl^ , air expands or contracts O.t)02t).'>r) of itH vohnue ; and tliis is known as the coeilieieiit of cx[)ansi(»n for I'^ahren- heit degrees. Thus, 1 liter ol' air, limited to 40° C, will expand to 1 +(40 X 0.00;5()(J4 104° F. (104° F. = 40° C), it will expand to 1 + (72 X 0.002030), which equals 1.14(545)2, as before. Again, the same volume cooled to — 15° C, will contract to 1 — (15 X 0.00.30(348), or 945 cc. ; or cooled to 5° F. (5° F. = 15°C.), it will become 1 —(27 X 0.002030) or 945 CO., SIS before. So au apparent volume of 1,000 cc. at any tem])crature above freezing is iu reality a smaller volume expanded to that size ; and at any temperature below, is a larger volume Ijrought to that size by contraction. To correct volume for temperature, we must divide the apparent volume by 1 plus the ])roduct of 0.0030648 times the number of degrees away from 0° C, or in case of temperatures below- freezing, by 1 minus that amount. If the Fahrenheit scale is used, the appro- priate coefficient and factors must be substituted. Thus we may employ a set of formula) as follows : For tomporatiiros al)ove 0° C V- P'ov temperatures lielow 0° C V- For temperatures above 32° F. . . . F = 1 + 0.003G648./i° C. V 1 — 0.0036648.«° C. V 1 + 0.002036 (<°F.- Tr For temperatures below 32° F. . . . T"^^ -0.002036 (32 — <° F.) In the above, T^ ^ correct volume. !''= apparent volume. Inasnnich as volume is inversely proportionate to pressure, the ti'ue volume at any observed ]irossure is obtained by multiplying the apptirent volume by the barometric pressure expressed iu millimeters 308 AIR. or inches, and dividing the product by 7(50 or by 29.92, as the case may be. AA\^ may use, theu, this formula : 760 Applying it, we find that an apparent volume of 1,000 cc. at 750 mm. becomes 1,000 X 750 oQ^ -^ ~ =98/ cc. 760 or usiug the other scale, the barometer standing at 29.53 inches (29.53 in., 750 mm.), it becomes 1,000X29.53^33.^^^ 29.92 If the barometer reads higher than the standard pressure, the true volume will be grciiter than the apparent. Thus, suppose the pressure to be 30.22 inches, then 1,000 cc. "will represent MOiX 3022^1 010 cc. 29.92 ' Instead of going through two separate calculations, we may make both corrections at once by means of one formula which is a combina- tion of the two kinds already used. For temperatures above 0° C. the correct volume is obtained by means of the folloAving : V^. ^'X^ (1 + 0.0036648.<°) 760 By changing the plus sign to minus, the formula is adapted to tem- peratures below freezing. If the Fahrenheit thermometer is used, and the barometric pressure is expressed in inches, the formula is as fol- lows : r= V 'XB _. [1 + 0.002036 {t°F. - 32)] 29.92 and if the temperature is below 32°, it must be changed to V=- V'XB [1 — 0.002036 (32 — t° F.)] 29.92 In these formulae : V = correct volume. V = apparent volume. B = barometric pressure. t° = temperature. In order to avoid the tedious process of multiplication and division which the working of these formulae involves, recourse may be had to the admirable tables of Dr. Walter Hesse,^ wherein can be found the correction to be made for all temperatures between — 2° and 30° C and for all pressures between 680 and 770 mm., by simple reference to the proper column. ^ Tabellen zur Reduction eines Gasvolumens auf 0° und 760 mm. Brunswick, 1879. EXAMINATION OF A 1 11. 300 l^'or iill priU'-l.if'ul purposes, tlic ♦•(icnicicnfs of cxpiiii-ion rnav l»c Hh()r(,(iiic(l (o 0.00.'>()() jiiid OMiVl, lliiis !ivoi(liii|r miicli (i;.'iiiiiiM^ wliich luis V(!iy \\\\\{\ iii(Iiicii('(! oil (lie cud results. Example of Method of Reckoning CO,^. — (Jjipjicity of K;ini[)lc l)ottIe, .*},S8r) (!(;. 25 (;sl:i,iiii:ilc(l by rroCcssor L. I'. I\ liniinill ,' of f lie WoniCHtcT r(»ly(,('('liiiic. I iislil-nlc, wlio li;is (■iii|)l(iy(;as is |)resen(, no ehaii,i;'e oecnrs. The test is a-pi)lied in (he ibilowinn; manner: A few dro])s of blood well dilnlcd with waier are exi)ose(l to the air in a Jar, and bronull) containing ]ialladium chloride solution. The other tube serves as an outlet, and is connected with a series of three potash bnlbs containing respectively lead acetate solution, dilute sulphuric acid, and palladium chloride so diluted that it has a bright-yellow color. The terminal bull) is con- nected with an aspirator, wdiich, when set in action, draws a current of air through the live ditierent pieces. The flask containing the blood is heated on a water-bath for fifteen to thirty minutes with occasioual shaking, and meanwhile a slow current of air is drawn through the api^aratus. AVhen the blood begins to change color, the carboxyha^no- globin decomposes and yields its CO, which reduces the ])al]adium contained in the terminal bulb. The chloride of palladium in the first bulb is used for removing any traces of the gas and of other rel' Mil. '513 be t|io-e(| [o he 'lemon-t r;ifel;iicli. ( ^n;i nt it;il ive de|erniiii;il ion- are lliiidc l>y con I purine- ihc lint, willi a standard scale, the depth of nAov Ix'int;' (l(!|)('ndenl upon the anionnl oC i(»dine liheraled, and this iipf»ri th(^ aiiioiinf of ozone |)resent. Thi' |>ap(;r.s arc prej)ar(;d in the follow- ing iiiiimicr : l^'roni 2.5 to 10 j^ranis of starch arc; taken, acconJiiig to the recoinnicndat.ions followed, and, after trituration with a Hrnall atnoiint of ('(»ld water, are hoiled for ahont ten rninute.s in ahoiit 200 vc. of water, and llltered. ( )ne ^rani of jxitassiuni iodidf; in soln- tjon is next added t^i-aduall}' with constant stirrinL"-. Strips of wtout liltor-paper, wet with distilled water, ar(! soaked in the starch prepa- ration until they are thoroughly iuipree is detached and placed either in a drying-oven or in a desiccator over sulphuric acid, and kept until it ceases to lose weight (moisture). The 314 AIR. lU't ineron.^e in ^vt'i^■llt represents the amount of dust in the vohnne of air aspirated. To determine the nuniher of dust partieh\>^ in a oiven volume, the method of Aitkin is employed. The ajiparatns inelndes a shallow metallic box with ^lass top and bottom etched in squares. Into this box, containing air which has been freed from dust by iiltration through cotton, and is kept saturated with moisture by means of wet iilter- paiHU", a small measured amount of the air under examination is in- troduced. By causing the formation of a partial vacuum, each par- ticle of dust becomes coated with condensed moisture and hence tends to fall upon the etched squares of the bottom. The number deposited is counted with the aid of a magnifying glass. The number of ])ar- ticles varies, according to Aitkin's observations, from 8,000 to 100,000 per cubic inch in the country, and irom 1,000,000 to 50,000,000 in cities. Bacteriological Examination. — The method which involves the least trouble and requires a minimum of apjiaratus, and which for all practical purposes gives greatest satisfaction, consists in exposing gelatin plates or Petri dishes for a definite period, and then covering them and letting the colonies develop. After the ])roper interval, the nnnil)er of growths may be counted, and the indi^'idual species isolated and studied. This method is very useful for comj^arative work, the results being given as the number of colonies M'hich develop after a given exposure. For more accurate quantitative work, Petri ^ devised a process of sand filtration. A glass tube, 9 by 1.6 cm., serves to carry two small filters, which are arranged in the following manner : Two small tightly fitting diaphragms of fine wire gauze are inserted into the tube at a point midAvay between the ends. Into one side, a quantity of fine quartz sand is packed, and upon it, to keep it in place, another dia- phragm is driven. Above this, the space is filled with a cotton plug.. The tube is now reversed and a second filter of sand is made in the same way. After complete sterilization, the cotton plug in one end gives way to a rubber stopper with a single perforation, through which passes a glass tube connected with an aspirating pump. The other cotton plug is removed and the process of suction begun. When a sufficient amount has been drawn through, the two filters are removed, each by itself, and mixed with the nutrient gelatin from which plates are next to be made. The first filter should contain all of the organisms, the second serving as a control. Ficker suggested an improvement in the construction of the filters, substituting for sand, which to a certain extent, masks the colonies, powdered glass, which has not this disadvantage. A still better material is fine sugar, the use of which was suggested first by Sedgwick. The advantage of this is that it is dissolved in the liquefied gelatin, and thus disappears from view, and, therefore, neither masks the colonies nor can be mistaken for them in counting. ^Zeitschiift fiir Hygiene, III., p. 1. EXAMINATION OF A III. '515 Sc(l|jJwi('l<',M inclliod of collccl iii^-- <)r}_';iiii-iii~ ;iiirld in m- vertical position Nvitli tli<' narrow portion down, the pln<2;s are removed, and m measured volume of" air is drawn through by means of an as|)iratiiiLi; ap|)arafiis connected hy a riilthcr tube to the lower end. When the desired aiuoiint of air has been asj)irated, the suj>;Mr with the bacteria which it has arrested is brouivsciil. Win n :-;in t('rniH, li(»W(!V(r, li.i\«' no r< rcirncc lo wci^lil, l>iit lo llic i-m-c or (liirKtnlty vvilli vvliicli tlicy iirc \\oil((l in I lie procc.sHut not all the ammonia of the soil is from this source, for some is brought into it from the air by raiu. And in the Till': SOI!.. riio HC!(!(Hi, il, ;i|>|K:irs In he iiol, :iv;iil;il>l(' wr. pl.-iiil IVtod, hiil, <'Vcii, ."iccordilin- (o |',()i|cli;ii'(|;i( ;iii amount of oi-yanic matter in soils varies widely according U) (arenmsta.n(^(!S, hut tlu; amount necessary (or veu-etation is (piite small, althou,i;'h certain croj)s, as tohacco and wheat, riipiire niiich more than others, as oais and rye. 'I'he soils richest in orj^anic matter are the peats and uuicks ; next couk.' the very rich humus soils, whieli may yli^ld more than a loiirth of their weij^ht. l^^'om 10 to 1 "> jK-r a-nt. denotes unusual richness, and al)out (! per cent, may he regarded as a fair amount for a productive soil. Physical Properties of Soils. — Pore-volume. — Ju all soils, no mat- tor how closely the individual particles are ])acked, there must exist a greater or less amount of interstitial space, which may \ni filleil with water or aii", or hoth together. The sum total of these interstitial spaces is known as the ^w/'o.s//// i)v pore-volume, and is expressed in per- centage of the volume of the soil. Its amount depends not uj)on the size of the soil particles, hut U])on their uniformity or lack of uniform- ity of size, and u[)on their arrangement. If Ave have, for instance, a Fi(i. 17. Via. 18. v^ery coarse S(mI, ct>nsisting of particles of uniform size as large as peas, and another of uniform particles the size of small shot, we shall find, on determining their porc-vohime, that it is practically the siime in each case, and is probably not far from a third of the whole. Packed in the most solid manner ]iossible, which is that in which each sphere rests on three beneath it (arranged like the familiar pyramid of mar- bles), helps support three in the layer above it, and comes in contact with others at six equidistant points along its equator, as in Fisr. 17, the volume of interstitial space will equal 25.95 per cent, of the whole. Packed as loosely as possible, so that each rests upon but one, sup- ^ Deutsche medicinisclie Wochenschrift, ISSG. 320 THE SOIL. ports another, and comes in contact Avith but four of its neighbors in the same layer as itself, as in Fig. 18, the volume of the interstices will be 47.64 per ceut.^ Thus a soil composed of spherical grains of uniform size ■would have, regardless of the coai'seness of the grains, a pore-volume of not less than 25.95 per cent. That the size of the individual grains makes no difference, may easily be demonstrated in a practical manner. If we take two cylindrical glass vessels of the same size, lill them to the same height with water, and then add to the one a measure of large shot and to the other an equal measure of nuich finer shot, and secure as solid packing as pos- sible by gentle tapping, it will be found that the water in each cylin- der has risen to practically the same height ; that is, that the actual volume of each is about the same. There will be, perhaps, some slight diiFerence one way or the other, owing to the impossibility of securing absolute uniformity of packing, and to the error due to the inequality of the spaces along the circumference of the cylinders. But in nature we do not deal with perfect spheres or with soils made up of particles all of the same size, but with soils composed of angular pieces of varying size. The greater the variation in size of tlie particles, the greater the possibility of variation from the limits of pore-volume as given above. With varying size, the small particles may fall into the spaces made by the larger ones, and the spaces between the new comers may be trespassed upon by still smaller grains, and so on until the interstitial space has been reduced to a minimum. To illustrate this diminution in a practical way, fill a large beaker with marbles, then pour into it, from a graduate, sufficient water to displace all of the air in the interstices, and note the amount of water required, which is the pore-volume of the mass. Next, pour out the water as completely as possible and run on to the surface of the marbles a quantity of coarse sand or shot, and shake the vessel gently in all directions so as to favor their descent into the spaces below. When all have penetrated that can, pour in water again until it ap- pears at the surface, and note the amount required ; this is smaller than before, on account of diminished air spaces. Now pour off the water a second time, add still finer shot, and repeat the operation as before. So long as new matter can be added, so long Avill the pore- volume show a diminution. Irregularity of size and shape of the particles may also have an in- fluence in the other direction, and cause the formation of large spaces and increased pore-volume. All soils, even the most compact rocks, have a certain amount of pore-volume, and some apparently compact masses, such as sandstone, have as much as 30 per cent. In soils which are cemented into homo- geneous masses, the pore-volume sinks to a minimum, but in ordinary soils it amounts to about 40 per cent. Permeability of Soils. — The permeability of a soil to air depends not, as it might appear, upon the amount of its pore-volume, but upon ' Soyka, Der Boden, Leipzig, 1887. Till': SOIL. 'VI I tli Naturoofdoll. M(!(liiini \s,\-A\n;\ CoiiiW! H.'ind IMcdiiiiii siiikI . l''iiu! Siiiid . . ■M.\) 'M.'.) Wl.'.) -li.r, 55.5 55.5 ;il)Hcii IVdni from JlllMCIl from from .'iliHcn fi frurii !ll)HCII from from !lI).S('ll froin from ahscn from from t, ;iliov<; Im;1ow I, illlOVC liclow !, !il)ovi; liclow I, !ll)()V(r Ik.Iovv t IlllOVO l)(;loW t, :ii)ovo below I'roMturo, 20 20 20 '10 '10 '10 40 '10 40 150 150 150 150 150 150 150 150 150 Itatio of fttr pflMKXl. 15.54 14.«3 1."..70 14.04 i:'..l« 12.55 2.:« i.tn 1.71 0.57 0.11 0.00 0.04 O.O.'i 0.00 0.01 0.00 0.00 l\'niu';il)ilitv is Icssciu'd also Wy iVcczino; temperatures, by reason of the iiuit tliat tlic contaiiu'd nioistiiix! c'.\|)aii(ls about one-eleventh of its vobune as it IVee/cs, and so occupies that nui(;h more s[)aee in the int<.'r- stices. Moreover, when frozen, the moisture is in a fixed rather than a movable condition, and causes tlic production of a compact ma.ss more or less resembling; stone. The finer the grain, the more solid the ])ro(hu't, and the o;reater the diminution of peruu^ability. Reid< ' deter- mined the diminution in the permeability of soils of different grain size due to freezing, as follows : Nature of soil. Medium gravel Fine gravel . . Coarse sand . . Medium sand . Source of moisture. from above " below " above " below " above " below^ " above " below " above " below Permeability. Moist. 14.63 13.70 13.16 12.55 1.91 1.71 0.11 0.00 0.23 0.00 Frozen. 13.87 12.20 12.54 10.18 1.64 1.27 0.07 0.00 0.00 0.00 Diniinuti/>n. 5.2% 10.9 5.4 19.0 14.1 25.7 36.4 100. The degree of permeability of soil to water, like that of permeability to air, is governed by the textui'e rather than by ]i(^re-voIume, as i.^ shown by the following results obtained by von Welitsehkowsky," who determined the rates at Avhich water Avould pass through columns of soil of differing fineness packed in cylinders of equal diameter. Each ' Boitnio- 7,nv Kenntniss der Permeabilitiit des Bodens fiir Luft : Archiv fiir Hvgiene, II., p. -I8;i •' Kxperiiuontolle Untei-sucliung iiber die Permeabilitiit des Bodens fiir Wasser, .Vn-luv fiir llyo-ioiie, II., p. 499. 324 THE SOIL. specimen M'as first completely saturated and then kept so during each experiment, the M'ater supplied being kept at constant level. Height of column of soil. 25 cm. 50 cm. Height of water column above soil surface. 20 cm. 1 50 cm. 20 cm. 1 50 cm. " Nature of soil and size of grain. Amount of water discharged in liters per min. Fine sand, less than J mm Medium i^and j^ to 1 mm 0.00024 0.175 1.767 8.570 14.909 0.00059 0.435 4.014 16.190 0.00014 0.123 1.351 7.465 12.872 0.00028 0.237 2.422 Fine gravel, 2 to 4 mm Medium gravel, 4 to 7 mm 11.705 Comparing these results with those obtained by the .same investi- gator in his experiments on permeability to air, it will be noticed tliat the total pore-volume has here even less significance. Nature of soil. Height. Pleasure. Pore- volume ^. Batio of permeability. To air. To water. Fine sand . . Medium sand Coarse sand . 50 cm. 50 cm. 50 cm. 50 cm. 50 cm. 50 cm. 41.87 40.64 37.38 1 155 1,276 1 846 8,650 Capacity for Water, and Water-retaining Capacity. If to a volume of any soil packed into a cylinder of glass or metal we add w^ater in such a way that all of the air in the interstices is dis- placed, the soil is then saturated and the amount of the contained water represents the total " water capacity," which, it is seen, equals the pore-volume. The "water-retaining capacity/' is quite another thing, and depends upon the structure and composition of the soil, and, in a minor degree, upon other considerations. If for the imper- vious bottom we substitute one of wire gauze or coarse cloth, the con- tained water will begin to drain away, owing to the force of gravity, and the flow will by degrees become less and less, and finally cease. Then the interstices, which originally were filled with air alone and next with water, are filled in part with the one and in part with the other. By comparing the original weight of the volume of soil with its weight in its now wet condition, its power to retain water is easily de- termined. This power is the result of tw^o forces acting in opposition to the force of gravity ; namely, surface attraction of solids for liquids, and capillary attraction. The water which is simply adherent to the surfaces of the soil grains is known as hygroscopic water, while that which is held in the capillary spaces is called capillary water ; and it is the latter which, in any but the coarsest soils, constitutes by far the larger part of the retained moisture. Not all of the interstices of a soil form capillary spaces, but only those of which the boundary walls are separated only by intervals CAPAdlTY FOU WATKIl, AND WATEn-llKTAIMSd CAI'ACITY '525 wlilc.li roinc williiii llic liiiiils ol" (•:i|)ill;iry inaf^iiiliid*'. TIiiih, a (!OiirHC Koil may coiiliiiii (;oiii))aiiitiv(;ly lew .sucli HpaccH, while oik; of" u fine tcxtuH! may liav(! ils particlcw ko cIoHcIy a|)|>r()xiriiuter(rolalioii, ;iiiy hhick clotlics lliiiii \)\ \\lii(<' in tlic ljri;.f|il -iiri- sliiiic. So, oilier <',oii(lil,ions l)ciii<^ I lie siiiiic, u (l;irU s<'ar Id he inneli liotler lh;in il i-ealiy is. 'V\\v. indiK'iK^e of conipac.l.ness on soil tciii|)eraliire varies with the season. Aecordinn- to Kino-,' ihc general tendeiic\' of rollinjr ilic hind is (() inak(! il. wanner during hri;;lil, sunny weather, hut in elondv or cold weather it lends to pronioti! (;ooliii<^. \\v has observed that, at tluMlepth oC 1.5 inches helow the siirCaee, a rolled fi(!ld may have a toinjK'raturc U) (lc!erlieial Ix-d of vegetal)h! monUl passes tin-onnh iheir hochcs in the (jourse of every few y(!ars." I^^-om various data, l)ar\vin eai(;uhitcd that th(! {xistin^, spn^ad out uniformly, woidd f"orm, in the course of" ten yj^rs, a layer varyiiifj^ f'l-om O.S,''), in (he eas(! of a very jxtor soil, to 2,2 inches in ordinarily rich soils, 'iheir mechanical action and that of ants, moleH, and other burrowing animals have much to do with keeiiiug soils open and friable. Soil-air. The air in the int(M'stices of the soil differs from that of the atmos- ])here mainly in its i-iehness in carbon dioxide, which arises l"rom the decomposition of organic matters. It is also poorer in oxygen, but by no means always in a corresponding degree, and it is usually quite humid by reason of the presence of soil moisture. The amount of carbon dioxide varies very widely in different soils and at different de])ths of the same soil, and it fluctuates very consider- ably also under differing conditions at any given point in the same soil. Other conditions being the same, the amount is most marked in .soils rich in organic matter undergoing decomposition-changes. In soils poor in this respect, the amount may be no greater than in the atmos- phere. Pettenkofer, for instance, found in the air of desert .«and, which was devoid of organic matter, the same amount as was present in the air immediately abov^e it. In ordinary soils, the amount increases with the distance from the surface, as has been shown by Fodor,Mvho made a great number of analyses of air at different depths at a number of places, the ob.serva- tions extending over several years. The average amounts found at depths of 1, 2, 3, and 4 meters, expressed in parts per 1,000, were as follows : Depth in meters. 1 2 3 4 Station 1 4.8 13.7 18.1 1 6.6 14.3 28.4 20. i 28 7 Station 2 Station 3 36 5 The influence of season also was shown by him to be very considerable, the highest amounts occurring during the hot months, and the lowest in winter. The averages bv months are presented in the following table : ^ Boden und Wasser, Braunschweig, 1SS2. 330 THE SOIL. Mouth. Jamiarv . Febniarv . March ." . April . . May . . . June . . . July . . . August . . September October . November December Depth iu meters. 6.5 6.8 7.0 9.9 11.5 14.5 15.8 12.8 10.9 9.8 8.4 8.1 12.6 12.2 11.8 14.9 IG.l 21.5 22.8 20.7 19.3 15.0 13.8 12.6 25.0 24.8 24.7 25.2 27.2 29.2 35.9 32.6 31.4 29.4 26.5 25.8 Fig. 19. These results are only such ns might be expected when we consider that decomposition of organic matters proceeds most vigorously within certain limits of high temperature. Fluctuations in the amount present at any given point arc due to a number of conditions which include rainfall, the action of the wind, the rise aud fall of the subsoil-water, and differences in atmospheric pressure and temperature. Rainfall, by tilling the superficial interstices of the soil with water, interferes with the natural process of soil ventilation and causes an immediate accumulation of carbon dioxide, which, however, is shortly followed by a diminution due to absorption of the gas by the water, which thus acquires an increase in its power of attacking and dissolving the mineral constituents of the soil. Inasmuch as the bulk of the absorbed rainfall is held by the upper strata of the soil, its influence is more marked there than at greater depths. As it sinks downward, however, in very \vet weather, it drives the air before it, and causes its escape at points where its egress is not obstructed. The action of wind is exerted in two ways: by perflation and by aspiration. By blowing strongly across the surface of the soil, it aspirates the air in the upper layers and causes an upward movement in the air below, or it may suck it out at one mo- ment and take its place the next. Again, it may blow with such force against the surface as to drive the contained air downward before it, so that the interstices become filled with ordinary atmospheric air. The action is more marked in soils of ordi- nary coarseness of texture than in very open soils with large interstices, which permit freer movement in the upper strata. This may readily be demonstrated by means of a simple experiment with the apparatus shown in Fig. 19. Here we have a glass cylinder, inside which is a glass tube extending from the bottom Apparatus to show action of wind on soil air. SOIL- A in. •'!•"' 1 and l)Oiit ovor at ilio top ho uh (o foi'in a U, info wliirli an anion iil of wat(!r snirKricnl, lo (<'ftii a sc-il rri;iy Ix- inl rodncfd. If ii<»\v \v«- fill the intorveninji; s|);i,c,c up (o the (op willi siiikI, ;iii(I iIkh direct a^riinHt tlio Hnrfiiec of IIk! lallci' ;\. einTcnt oCair by nicMn.s of ;i IjcIIowh or liy l)Io\v- \\\\f sliiirply tln-on<:;li a tnlx; of p;lass or other niafx-rial, the whole volume of air in tiie inters! ic.(!,4 is set in motion, wliieh is comniiinicati-d to the !iir within tlu; enc^loscd t.nhe, so that the water in the U-shaped dcpn-K- sion is eansed to oscill.ilc. If \\\v. water complet hand, hy its rise, foreinn; (lie rich soil :iir iipwiird :ind lace ; namely, hvgrosco])ic, ca}iillary, and gravitation. Hygroscopic water is that which adheres to the surfaces of the soil particles in the presence of air. A certain amount of moisture is con- densed upon the surface of most solid substances exposed to ordinary dampness, and it adheres with great tenacity. The amount of water so obtained differs, other conditions being the same, according to the nature of the soil, some soil constituents surpassing others in their powder to attract it. Thus, soils rich in organic matter (humus) have a greater degree of hygroscopicity than others in which this constituent is present to a lesser extent. In some soils, the amount of hygroscopic M'ater is very marked by reason of the large amount of organic matter, and because also of the large surface area presented by the soil particles. Some idea of the tenacity with w^hich this moisture is retained may be derived from the fact that air-dried soils w'hich appear to be quite dry — the dust of country roads, for instance — may yield as much as a tenth of their weight of w^ater on complete drying by ordinary labora- tory methods. Both the moisture absorbed from the air and the water held on the soil grains by surface attraction after a condition of decided wetness has been changed by the draining away of the rest, may be termed hygroscopic. The capillary moisture is that which is held within those spaces which have been spoken of as capillary in their nature. Under ordinary conditions, these are intermingled with spaces which may not be so designated and wdiich contain air, and so the capillary moisture does not ordinarily equal the pore-volume. The water in the capillary spaces may be that which is retained after thorough wetting from above, or it may have crept upward or laterally from points completely satu- rated. Capillary movement occurs in all directions, but it is most marked from below upward to points wdiere water is being withdrawn by evaporation or by the demands of growing vegetation. The height to which water may rise by virtue of this force depends upon the diameter of the spaces ; the smaller the diameter, the greater the rise. Jurin's law of capillary movement is, that the height of ascent of one and the same liquid in a capillary tube is inversely as the diameter of the tube. Thus, water will ascend ten times as high in a tube having a diameter of 0.1 mm. as it will in another with a diameter of 1.0 mm. It follows, therefore, that capillary movement is most marked in soils of fine texture. Capillary movement is influenced materially also by temperature and by the nature of substances held in solution. It diminishes as the SOIL- WATER. o''"3 tcmi)(!nitiir(! riHdH, and iiKToaHii.s uh tlic liil vvilli iincvrn Iciiipcraliircs, flu; motion will !«; didrnMil, acc.ordiiijr as (Ik; (cMipcraiMrds vary. 'I'hns, if (lie lower |»art of a colnnui o(" soil Ix; <',oolcd, the surface f<'nsion of its contained waier will l)e iiuu-eased ai, lliai point, and water will he ;itlr;ieted from \\w. |)ar(,s above, }z;ravil,y assisting ; wlier(;as, if it he heated, its con- tained water will he attracted npwanl. In satnra((Ml soils, motion of the water in any direction is in(lnenr-ed very greatly by tem|)eraliM'e, becanse of tlu; elfeet of heat in chan^in^ the viscosity of water. The higher Ihe tompcralnre, the ^rcat<;r tho diminntion in viscosity and the freer the movement. 'V\\v, indnencc of dissolved snbstances dc|)eiid.- ii|Min thiir natnre, Konu^ favorinir, and others retarding;, movement. 'V\h'. rate is increased by the presenile of nitrates, and is diminished by common salt and snlphatc of calcinm ; bnt the favoring; infln<'nee of the prcHenw of nitrates is connteraeted most markedly by orcom]>osition of matters of vc^;ctable oriugh the soil by the force of gravity and accumulated in the sul)sr)il over an impermeable stratum which has arrested its farther downward journey. This is what is commonly known as ground-water, or subsoil-water. Its zone extends from tlie surface of the impermeable barrier upward to that point where the interstices of the soil cease to be completely filled with water, but are filled partly with air. This point is knf»wn as the ground- water level. The zone above it, through which water is moved in the capillary spaces, is known as that of the capillaiy soil- water, and extends as far as the water is moved through that force. Above this, at and near the surface, is the zone of eva]>oration, from which water is evaporated into the atmosphere. The impermeable stratum beneath the subsoil-water may be either very fine sand, compact clay, or rock. It may be thin or thick, accord- ing to circumstances. Behnv it, there may be a succession of alter- nating permeable and impermeable strata, so that in driving deep wells a variety of strata are pierced, and waters of varying composition may be secured. Dense clay is practiciilly impermeable to water, but at the same time it can communicate its moisture to surfaces with which it comes in immediate contact, a fact which renders necessary the in- terposition of damp-proof material in the foundations of houses built upon it. ti 334 THE SOIL. Rocks vary greatly in impermeability ; the densest of them contain very small amounts of moisture in their pores, while others are so porous that they may contain as much as a third of their volume of water. Auaiu, most rock de})osits arc more or less fissured and seamed, and thus permit to a greater or less degree the passage of M'ater at these points. The water-bearing stratum is usually gravel or sand, but may l)e porous or fissured rock. Its depth is exceedingly variable, dejK'nding upon local geological conditions, and at two jwints not widely separated, it may be respectively slight and considerable. The ground-water is in constant motion both laterally and vertically. Its lateral movement, whatever its rate, depends u})on the configuration of the impermeable layer below, and not upon that of the surfiicc of the land. Generally speaking, the direction of the movement is toward the nearest large body of water, be this the sea, a lake, or a river ; but it is not often possible to determine, except in a general way, from surface observations, whether at any given point the flow is in one direction or another. This is especially true when the water-bearing stratum is thin and underlaid by an impermeable stratum of very irreg- ular conformation. The rate of movement is also exceedingly variable ; it may be fast, or slow^, or hardly perceptible. In Munich, for instance, according to Pettenkofer, it amounts to about fifteen feet daily, while at Berlin, it is only very slight, and at times is wanting. It is influenced by the configuration of the subsurface, by the perme- ability of the subsoil, by the amount of the accession of moisture from rainfall and melting snow, by the obstacles interposed by the roots of trees and other plants, by others at its outfall, and by the withdrawal of moisture by the needs of vegetation and of communities of men. The rise and fidl of the ground-water — that is, its vertical move- ment — depend chiefly upon the amount of rainfall ; and, on the other hand, upon the rate of withdrawal by evaporation, vegetation, and Avater supply of communities, and upon the freedom of, or obstacles to, the outflow. The effect of rainfall is generally not immediately perceptible, for so much time intervenes between heavy falls and penetration that a falling of the ground-water level may continue to be observed for a long time after a period of great wetness ; but when the level rises, it is a proof that additions have been received from above, though per- hapvS the accession has travelled through a long distance in the soil. When the level falls, it is a sign that the upper strata have become dry through evaporation, and that capillary attraction has carried moisture upward to replace the loss. The rise and fall of the ground- water level may be determined by measuring from day to day the distance between the surface of the soil and the height of the water in a number of wells in a given locality. This may readily be done by means of a tape-measure or chain to which SOIL-WATKIl. "•>■> is jit(,:i(;li(Ml ;i nxl Ix-uriiip; ;i, iiiiiiilxr oC sliiillow rrict:illic riips wliicli Jirc, I()Wci"<' - 1 fillt ill uliidi Wutf.T Ih found indic.'ilcs \\\r |iositiuii of tin- \v;ilcr-lcvcl uilli i'i:-|iiy cfciilina; mw onlliUls by dilcliiti^ rnon; or less dc(!|)ly, ;ic(;(»rdin<;' lo iiidi\ idii.d conditioiiH, by Hiiildn^ drainage wells, or l»y liiyiiit; ; acitive V(!g(;tation, may penetrate but very slightly beneatli the sin-face. In early sprin*; and in au- tumn, the anioimt which percolates downward is natni-ally much larger in |)roportion. A by no means insignificant amount of nioLst- ure is that derived by absor|)tion and condensation from a moist atmos- phere. In periods of drought, this power of dry soil to absorb water from lumiid air is of the greatest value to vegetation. The amount absorbed tlillcrs aticording to the; nature and hygroscopic ity of the soil elements. Thus, a soil rich in humus will attract more water than another composed wholly of sand. Condensation of water occurs when the surface is cold and in contact with moist air. This contlensatiou may occur from above or from the rising moist soil air just below. A third source of moisture, of no great importance, is the breaking up of organic matter into its constituent elements, in which process the hydrogen is in great part ultimately released in combination with oxygen as water. Another and exceedingly important source of soil moisture, important not because of the amount, but because of the (piality of the water, aud because of its possible effect on the supply of drinking-water and on public health, is the waste waters incident to human life, which in so great a })ro}iortion of communities are dis- charged directly into the soil, where, being out of sight, they are equally out of mind. Loss of Soil Moisture by Evaporation. — The amount of water which a soil loses by evaporation is infiuenced by a number of fictoi-s, which include the water content of the soil, the height of the jiermeable layer, the composition and structure of the soil, and the character of its surface, and, particularly, whether it is covered. In other woixls, the rapidity of the process is projxn-tional to the combined area of sur- faces exposed, and to the facility for replacing the loss by withdrawals from below. 336 THE SOIL. Influence of Vegetation on Soil Moisture. — The amount of water in soils is iutlueneed greatly by growing vegctatiou, which requires a vast supply for the proper inaiutenance of its fuuctions. It withdraws it by absorption by the roots, which extend down^^•ard to surprising depths, the roots of wheat, for instance, attaining sometimes a length of eight feet and more. From the roots, the water passes into the cir- culatiou of the plant, assists in the various physiological processes, and then, for the most part, is given off from the leaves into the atmos- phere. It has been calculated by Pettenkofer that an oak evaporates more than eight times the rainfall, and that the Euealyptus globulus is even more active. The difference between the rainfall's contribution and the amount exhaled represents the amount which has been with- drawn by the roots from the capillary spaces and from the water-table itself. As the water in the capillaries is relinquished by them, more comes up from below to take its place. Thus it is that a plant or tree acts during the growing season as a constantly working suction appara- tus tending to dry the ground, and so may be explained, in part at least, the condition of wetness that is acquired by some lands after removal of trees. All growing crops withdraw enormous amounts of water, and after the grow'th becomes well advanced, it is the capillary water upon which dependence is placed, for the rainfall penetrates but a short distance into cultivated land, and most of it is lost by evaporation. Were it not for the capillary water supply, no crops could be raised, except under most extraordinary conditions of weather and by artificial irri- gation, since but a short period of drought would suffice to produce wilting. According to Stockbridge,^ " The quantity of water thus required and evaporated by different agricultural plants during the period of growth has been found to be as follows : 1 acre of wheat exhales 409,832 pounds of water. 1 " " clover exhales 1,096,234 " " " 1 " " sunflowers exhales 12,585,994 " " " 1 " " cabbage exhales 5,049,194 " " " 1 " " grape-vines exhales 730,733 '' " " 1 " " hops exhales 4,445,021 " " " But the influence of vegetation on the water content of the soil is not limited simply to its withdrawal and evaporation into the atmos- phere, for it acts in the other direction to impede surface flow and sub- surface drainage. This is seen more particularly in the case of trees and forests. The forest cover keeps the soil granular and ])romotes downward percolation ; the tree roots, penetrating in all directions, present an effective obstacle to rapid lateral movement through the soil. Removal of forests and clearing away the surface of the forest litter promote sudden and destructive freshets in the springtime and drought when, later in the year, the water is needed. The ill effects of deforest- ation are noticed particularly in parts of Maine and in the Adiron- dacks, where streams that formerly ran full the year round are raging ' Kocks and Soils, New York, 1888. SOIL- \VA 'I'Kll. ''''7 tfMTcnls wlict) i\\r. wiiifcr's hiiovvk ;ir(! iiu'lliii^ iiiid Imi idsij^riilir-unt brooks or wliolly dry during' IIk; siiiniiicr iihmiI li-:. It, lian hfcn hUit«,-d hy M;ij(»i' Itnyiiiond, of (Ik; If. S. MiiHlnccrs, tli;i(, in foroHt urcjUH, four- IHlli.s of tli(! r;iiiil;ill arc savcid, wlillf in '■|(;iic(| l.mil ihc saiiic amount i,M lost hy (ivapor'atioii and siirCacc llnw. Other Effects of Vegetation Upon the Soil.- In addiiion U) it« inlliiciicc on (lie nioNcnicnt of soil-wald- and on il- amount, vegeta- tion is an im|)orl;inl fador in llic ddi i ininal ion oC soil temjMjruturc and of tli(! amoimt of mineral matter availalde lor siie(;e(;dinjf jrrowtliH. TIk! dee|)ly peneti'at ino; roots hrinjji; to the tissues of tin; ^rowin^ plantH a lar^'c^ ainouni ol" mineral m;illiis iVuin llic -nh.-oil. ( )ii th(; d'■) (|ii(!iitly ill (lie ex liiiiii.il ii»ii of Ixtdifs (or one (•;iii.sc or ;iii(ii Ikt ;i('t<'r Vary- ing |)(!ri(»(ls o(" iiilcriiiciil . 'Tims, in o|)cii noils, Ijodic^ miiy jHjiir nlmoHt- coiilplclcly ill I lie coiirsi' oC w few y^'JlPH, while ill htill" wet (iiiiyH Iriicy limy he IoiiikI even \i\\v.v Ivvcnly iiiwi iimih; ycurh lo Ix; |tiitrice with sand of different degrees of fineness, but Avith the same total jiore-volume, and to each was added from above an equal volume of solution of common salt, and then daily, for ten days, an equal volume of distilled water. The drainage of each day * IMiinohonor modioinislio Woohonschril't, June 6, 1899. '' Se'o page 341 for an unusually striking example. '' Uebor das Eindvingen von ^'eruureinigungeu m Bodeu und Grundwasser. Arohiv fiir Hygiene, XL, p. 145. 340 THE SOIL. was tested as to its omitent of salt, aiul it was found tliat, whereas that from the eoarser sand yielded salt on the second day and gave the higliest results on the third, from which time the yield progressively dwindled, that from the finer showed no trace until the sixth day, and its maximum on the seventh. Repetition of the exjieriment in the same way in all particulars yielded identical results. Thus it is shown that j)ollution travels more quickly in coarse soils than in fine. In the decom[)osition of proteid substances in the soil, basic sub- stances are believed by some to be formed, which may be tidveu into the system, and so affect the resistance of the body to disease as to favor infection. This, however, is purely hypothetical. As has been remarked, the presence of bacteria is essential for the resolution of organic matters in the soil. This has beeii illustrated in a striking manner by Duclaux,^ who treated sterile soil with sterile organic matters, such as milk, sugar, and starch paste, and then planted therein peas and beans. Although the resulting plants were well cared for, they did not thrive, but remained as thin and weak as though growing in distilled Avater. The organic matters in the soil were of no value in their growth, for they could not be absorbed as such, but only after decomposition. The addition of a little unsterilized earth sufficed, however, to start the required j)i"ocess, and then the growth improved at once. Bacteria of the Soil. The bacteria of the soil are found almost wholly in the superficial layers, and below a depth of twelve feet their number is I'clatively few. As they need organic matter for their growth and multiplication, it may be inferred that the greater the amount present, the greater will be their number. Thus, they are far more numerous in rich garden soil than in ordinary sand and clays. The conditions most favorable to their develojjment are, in addition to the presence of the organic pabulum, moisture and certain limits of temperature. Dryness and extremes of heat and cold are all unfavor- able ; saturation with water may or may not be, according to the vari- ety, for there are some that in a wet rich soil can go on decomposing organic matters. In ordinarily rich soil, the number of bacteria ranges from hundred thousands to millions per cubic centimeter in the surface layers, below which they diminish in number very rapidly, until, at ten to twelve feet below the surface, the soil is practically sterile, except for those that have been washed down or carried by burrowdng animals, or, as above stated, deposited by man in organic filth. The soil bacteria are maiidy of the beneficent varieties, the sap- ropliytes which perform only useful offices, including the numerous varieties of the nitrifying organisms. While different species of path- ogenic bacteria have been found in the soil, and although certain of ' Comptes rend us, C. p.A('r/':nfA or the sou.. f*>n iJicMi, the l>;icilli <.(' ici;iiiiis ;iiiC iii;i IIl' ii;i iil fi(lciii;i, ;irf yvxy ^i'm'V- iiJIy |>r<\sciil., (Jiis cImss of oi'Hiiiiisnis I'iihIs, ;is ;i rule, I he (■(»ii(|i(iuiiH |)i'(!S(Wi(, ill tlic, soil iindiA'ornhIc lo (l('Vclo|»iiir'ii(. In tlio first pliuic, (lie (ciiiiirniliirf i~ loo low, (•x<'c|)lin^ in tin- wry npiMU'inoHt liiycrs in \\;irni \vcaliir(!scnc(! of I Ih' i hoi monsly rnirncroiiH h:i|>- ropliyics, vviiiciii, in sonic ninnncr not. as yet satisfiU'torily explained, hi-injr al)onl, llieii- deslrncfion. This action lias heen deinon>t rated repoatodly by Ko(^li and ollieis, wIk) showed that anthrax haeilli and otiier |)atho<2;eni(^ varieties can ^row in sterili/e(|, hnt, not in nnsteril- i/ed, soil. Klein' insists that. |)athoiz;enie, or'. r'tddnris Kporof/ciics, which is always present in deeoniposinji; bodies, and that, in most cases, a month is sunicient time t(» insnre destru(!tion. He buried (i;ninea-pip;s con- tainiiiin' varions kinds of micro-organisms within the abdominal cavity, and at dilTerenl times exhnmed them and made search for livinj^ speci- mens. He fonnd that />. prodii/ioKiix lived 4 weeks, bnt not ; Siaph- yloeoceun ((.ui'ciis, abont the same; iSp. cholene, 19, but not 28 days; B. fi/pJiosii.s and />, (liplifherlfe, not lonjrcr than 2 M-eeks ; B. pe.sfifi, 17, but not 21 days, and />. lii,h('rcu!osi.s, not 7 weeks. It is believed that, in the dee])er layers, away from tlie saprojiliytes, the spores of pathogenic species may tind a lodgement favorable to storage, but not to development, and that there they may remain with dormant vitality. Many examinations of graveyard soils and of bits of coffins have been made by Dr. E. H. Wilson, of Brooklyn, to determine^ if jiossible, the presence of pathogenic bacteria as well as the number of bacteria as compared with those in other kinds of soils. He found no more bacteria than in others, and no pathogenic kinds whatever. There is one kind of soil that has been found again and again to have a destructive action on pathogenic bacteria, and that is l^eat, which kills them very quickly, probably through the contained organic acids. The soil acts as a very good filter, and holds back most of the organisms, but by the aid of flowing ground-water or water entering from above, they may be carried through considerable distances. Thus, Drs. Abba, Orlandi, and Rondelli,- experimenting on the filtration capacity of the soil about the filter galleries of the Turin water supply, found that cultures of Jficrococcus prodir/iosus, poured with large vol- umes of liquid into the ground at various points, made their appearance 200 meters away in 42 hours, and 12 and 27.5 metei's away in 7 houi^s. In these experiments the property of the soil for holding back sulv stances in solution was manifested in a remarkable degree, methvl-eosin and uranin, substances which impart intense red and green coloration to water, and which were added with the cultures, not appearing until * Twenty-eighth Annual Report of the Local Government Board, Supplement * Zeitschrift fiir Hygiene und Int'eotionskrankheiten, XXI., p. 66. 342 THE SOIL. long after the (M'oanisnis liad j)assi'(l throiio-li. In the instanee in Avliieli tlu'v appeared in 42 hours, the e()h>rinii; agents eoukl not be detected until after 75 hours had elapsed. The relation of the soil to the various pathogenic bacteria will bo discussed farther under separate headings. Soil and Disease. The influence of the soil on health and disease is admitted very generally, but is little understood. We know that certain soil condi- tions favor the occurrence of certain diseases, but why this is so remains a problem for future research to solve. Our notions concerning the causal relation of the soil are probably greatly in error with respect to certain diseases, being doubtless exag- gerated as regards some, and equally undeveloped with others. Com- position, permeability, temperature, moisture, evaporation, soil-air, and fluctuations of the level of the subsoil-water, all are supposed to bear important relations to many of the diseases of mankind and of animal life in general. Such evidence as bears on the relation of the soil to diseases is given in general terms below. Soil Dampness and Disease in General. — It has long been univer- sally noticed that dampness in and near the surface of the soil injuri- ously affects the health of those dwelling nearby. It causes coldness of the soil and dampness of the atmosphere immediately above, and appears to conduce more particularly to rheumatism, neuralgias, and diseases of the respiratory tract. It has been noticed by many who have investigated the subject, that the general health of those dwelling over damp soils is much inferior to that of those more favorably cir- cumstanced in that regard, and instances of improvement on renioval from damp to dry localities are too commonly known to need illus- tration. It is generally agreed that a soil in which the ground-water level is high, five to ten feet, for instance, from the surface, is not favorable to health ; and that a deep level, fifteen feet and more, is unobjectionable on the score of dampness. This being admitted, it might reasonably be inferred that artificial lowering of the ground-water will be fol- lowed by increase in salubrity, and, as a matter of fact, that is precisely what does occur. But it should be stated, in order to be historically accurate and in all fairness, that while increased healthfulness is a con- sequence, as a rule it is not the object sought, for, as a general thing, soil drainage, especially on a large scale, has been carried out to meet the demands of successful agriculture rather than in consequence of solicitude for public health. The methods employed may be stated generally as increasing the outlet and removing obstructions to the outfall. Ditching and the construction of underground channelways by means of drain tile or rubble and fieldstones are the most common methods of drain- ,S'0//, AM) DISEASE. -"'l:^, ilijj^. Soiiicl iincs, (li';iiii;iiic wells ;ii'(' (lri\r'ii ;il iiitci-\;il- (lowii f lifoii<.'|i tli(! irii|>(!nii(;;il)lc sli';iliiiii iiilo ;iii ojkii iih-'iil, inlo wliidi tli(\' flicn (lr;iiii. 'V\\v. (liniciill ics ill tlic \\;i\' nC di'.iiiiiiijj; cxlcii-ivc ;irr';is of iiiilic;ill liv itiid :ii;ri(Mil(iir;illy (iii|ir()(|ii('l i\'c ImihI li(! cliicfly in llic i;irl< of itnli- vidiiMJ <',()(")|)('r;iii(tii. SiictJi iin(l('r<:il;il, sliilc, or ii;itioii;il. By inOcins of iindcr-iiniiii.'iuc, I hoiisniids ;iiid t lioii-.-md- of ;icrc,- in various |)iirfs of (liis country, iiot;il»ly in Illinois ;ind Indiana, and vast; annis of land in IOnt;hiiid and on the conlincnf, have l>c(!n rtoii- vertdd from imlidallliy, nialarions, and inoicor li ~~ iinprodnctive tracts, into healthy and ridily |»rodn(;liv(! (uxinliy ; hut (lie scheme is not always snceessfnl in iclicNiiii; a loc^ality of disease, especially of malaria, as has been |)rov('(l in parls of Ilaly, Ansd'alia, and elsewhere. Soil and Pulmonary Tuberculosis. — There is an nndouhled eon- nection between this disease and soil dampness, which is most manifest when one investii>;ates the prevalence of the disease over the same soil before and wWer soil draina,^e, by which it will always be found to be diminished. Why this is so we can only (conjecture. We know that dampness is one of a possibly considerable nuinber of factors in producing predisposition to the disease. We know that, other conditions beinti; the same, the disease is far more common on low damp soils than on elevated dry ones. We know also that the disease is comparatively rare in some parts of the earth where the soil is exceptionally dry. The distribution of the disease and its relation to soil dampness were first brought to public notice by Dr. Henry I. Bowditch,' of Boston, at the annual meeting of the Massachusetts Medical Societv, in 1X62, who submitted two propositions, the results of most extensive investi- gation, which w^ere, iu substance, that dampness of the soil, whether inherent or acquired by reason of proximity of bodies of water, is an exciting cause of consumption, which disease can be checked in its course or even prevented by proper attention to soil conditions. Shortly afterward, similar conclusions were promulgated in England by Dr. Buchanan, who had been making observations along the same line, not knowing that Dr. Bowditch was similarly engaged. The.se propositions were accepted by the profession, and have been maintained ever since. Typhoid Fever. — It is believed quite generally that this disease is connected in some way with soil conditions as well as ^^•ith drinking- water. Indeed, there are some authorities who regard the soil a.s of infinitely greater importance in the causation of epidemics of this disease and of cholera than ilriuking-water, which to their minds has absolutely no influeuce one wav or another. The Pettenkofer theoiy of the cause of these outbreaks attributes it to the soil, from which the ^ Topographical Distribution and Local Origin of Cousuuiption iu Massachusetts. Transactions, 1862. 344 THE SOIL. exciting- cause is tlistrilnited by tlio groniul air, wliicli, as lias been stated, is in constant movement. According to the distinguished originator of the soil theory, the un- known poison is introduced into the soil, where, under proper condi- tions of organic filth, and other influences, a species of fermentation occurs, the end product of which is the exciting cause, which is then capable of inducing the disease in those by whom it is inhaled. All important in this process is the vertical movement of the ground-water, and it is certainly true that over a long period of years of observation at jNIunich, there was a most remarkable coincidence between epidemics of typhoid fever and fluctuations in the ground-water level. The condition most favorable to high morbidity was demonstrated to be a rapid fall after an unusually high level. The highest death- rates during the time covered occurred during the years of lowest level, and the lowest rates in the years of the highest level. A similar coincidence has been noticed elsewhere, but by no means in all or even a majority of the localities where investigations have been made. The theory had, for a time, many adherents, and the controversy between the soil-theorists and the "water-fanatics," as Pettenkofer called them, was carried on at times with exceeding bitterness. But within the past d('cade, the w^ater theory has been so thoroughly proved as the chief, if not the sole cause of extensive outbreaks, that interest in the theory has fallen oif, and its supporters are now few in number. Pettenkofer ^ himself, however, was to the end as uncompromising as in the beginning, and found no difliculty in applying it to the great epi- demic of cholera in Hamburg, in 1892. The contention that the extraordinary endemicity that prevailed so long at Munich was due to the filthiness of the subsoil, which was honeycombed with cesspools, cannot lightly be brushed aside, for it is a fact that, with discontinuance of these abominations, and with a system of improved sewerage, the typhoid fever rate fell from its posi- tion as a leader down among the lowest known. Nor was this fall due, as has been claimed, to change in the water sujjply, for the great ei)i- deniics had ceased, and the fall had long continued, before the water supply was changed. Experiment has shown that the typhoid organism may retain its vitality in the soil for considerable periods under favoring conditions of warmth and moisture. Robertson ^ removed sods from several places in a field, and wet the exposed soil with diluted typhoid cultures, one at the surface, one at a depth of nine inches, and a third at eighteen inches. After 130 days, the bacilli on the surface had multiplied, and where they had been placed eighteen inches below, they could also be found in the surface layer. Later on, in the winter, no results could be obtained ; but in the spring, he moistened the patches with sterile bouillon in very dilute condition, and afterward succeeded in obtain- ing growths. ^ Miincliener medicinische Woclicnsclirift, May 2, 1899. ' British Medical Joumal, Jan. 8, 1898. ,S'0//. AND DfSfCASE. .".15 Tlii.s posirivc I'f'siill ;i('(^or]\^£i-r tliaii fifl,(!('ii diiys. In iiir-dricd condition llicy appear to liavr- uriiinpain-d vilality ("or sonic days, accoi'din;^ lo I.rownicc,^ who rit it sliould l)c reinend)cred that air-dried soil r-ontains fronsidf^rahle liyfrr()S(;()pic water; conse(|nenlly his hacilli were donhtlcsH fairly well sM|>plIcd with the necessary moisture. OC moi-c importaiK!0, aji- parently, (han the (piestiou of moisture — Cor all soils j)tissess some — \H the nature oC the contained organic matter. hi. Sidney Martin''' has shown that nnp(tllntcd (vire;in) soils arc inimical to the typhoid hacillu.s, refi:;ardlcss of the anionnt of their contained organic matt<'r of vegetiible origin, while s|)ecimens containing polluting material of animal origin favor its existence. Such, after sterilization, were j)lanted successfully, and it was learned that, in the presence of moisture, differences in tem- perature had hut little influence. Thus, the organi.sni thrived alxiut equally well when specimens were kept at 98° F., at ordinary room tem])erature, and as low as .37° F. By no means the least interesting ohs(>rvation made was with regard to the duration of viability of the baciUus. In one of the sterilized polluted soils, the organism was still active at the expiration of 456 days ; and even then, after thorough drying and pulverization, active growth could be obtained. In com- jmny with various species of bacteria, among which the predominant kinds were members of the B. coll group, it was recovered after 50 days' exposure to temperatures ranging between 37° and 61° F. Later experiments,'' in which the tyjihoid organism was planted with different soil bacteria, proved that various species from a particular soil had the power of coniplotcly exterminating it within a short time, while others had no influence whatever. Therefore, it would apjiear, whether or not the typhoid organism can exist in a given soil, will depend upon the kinds of soil bacteria present, as well as upon special conditions of temperature and dampness. Dr. Martin found the period of vitality iu unsterilized soils to be about 12 days, but in no case did the organism appear to multiply. An experiment conducted by Levy and Kayser ^ to determine the duration of infectivity of this organism yielded most interesting results. The feces of a typhoid patient were discharged into a cemented vault, remained therein 5 months, and were then spread on a clay soil, from which, after 15 days of winter weather, the specific organism was isolated. Thev came to the natural conclusion that ' Zeitsclirift fiir Hvsjiene uiid Infectionskranklieiten, XXIV., p. 403. ^ Public Health, January, 1899, p. 272. =* Report of Local Governnient Board, 1898, London, 1899. * Ibidem, 1900, London, 1901. » Centmlblatt fiir Bakteriologie, etc., March 20, 1903, Abth. I., XXXIII., p. 4S9. 346 THE SOIL. typhoid stools ought always to be disinfected before being discharged into a privy vault. Tlio etfect of toniperature changes due to the presence of animal ex- creta mixed with the soil is shown by Gaertner ' to be considerable. He introduced cultures of various organisms in wire baskets into the interior. of compost heajis of various comjiosition, Mhich became heated tt) ditterent extents, and observed that the bacilli of ty]ih()id and eholera were the least resistant of all. With rapid and marked heat- ing, their life was short ; but it appears probable that in the absence of heat, even with the given surroundings, they may live through the winter. ITnder the ordinary heating that occurred in the comjjost, these two organisms were destroyed in a week, while the bacillus of tuberculosis remained virulent a number of months. But aside from what we glean from scientific research with the spe- cific org-anisms, we know from experience that there are many places with polluted soils where t}'phoid fever was unknown imtil the impor- tation of a single case from Avithout, and that, afterward, sporadic; cases, for which no convincing explanation is afforded, have occurred at varying intervals. And in country districts, whose inhabitants are not given to travelling much beyond the confines of their farms, it is noticed frequently that single cases occur in the same household at intervals of a year or longer. In such cases, it seems hardly reasonable to say that the original case has left nothing as the exciting cause for later attacks, and that fresh introductions of the specific organism must have occurred from some unknown source, for it is not unlikely that the variety of condi- tions that affect the viability of the organism may, in some cases, act to keep it alive, and, on occasions, stimulate it into a condition of aug- mented activity. Cholera. — Concerning the relation of this disease to the soil, there is but little to be said. Prior to the discovery of the specific organism, the soil theory of the origin of epidemic outbreaks had considerable vogue ; but now it is known that, even in times of greatest prevalence of the disease, the organism has never been found under natural con- ditions in the soil. It can be kept alive under certain favorable con- ditions of moisture and heat for varying periods ; but under natural conditions it is one of the least resistant bacteria and quickly dies. We have no evidence whatever that cholera is a soil disease. Bubonic Plague. — This has been regarded as a soil disease; and it has been believed, from the fact that rats have been conspicuous as vic- tims of it in the early stages of its devastating outbreaks, that these animals have acquired the infection in the soil, and have brought it to the surfiice, and thus acted as its carriers. But rats are notorious as frequenters of ])laces where filth of all kinds accumulates, and it is not strange that where they and filth al)Ound, they become diseased, if the infectiv^e agent is present. The whole question of etiology of plague has been cleared up by the * Zeitschrift fiir Hygiene und Infectionskrankheiten, XXVIIL, p. 1. SOIL AND DIShlASE. 347 diHCOVory tlijit flciiH, mikI especially l.lie eonniKiii i;il fle;i ( f'ufr.r /in/fiduM, (J(r ;i ^en- VX',\\ a{;Teeinenl lli;il a elo^e conneelinn e\i-t- l)ehv('(;ll Hoil (laiiipiic-s and the |)r('valence of this disease. Il is line ihal experiment has dem»»ri- slralcd the \ial)ilil\' oC IIk; orLcanistii in moisi, soils lor linnU-d periodn, l)U(. ir has ne\('r heen I'onnd in soils olliei- lli;in lliose in wliieh it wa8 doposilcd inlcntionallw 'The eonimon helief i> ||i;il ;i nioi;roun(l-\vaier low. "As Ioiiij: ^''^ •'"• ^'•'' i>^ well washed hy the wiutcr's hiji'h tide ;iiid aflerwai'ds dried and aT'rahd dni-inL*" llu; sumnior'H low tide, all o'oes well: hut so soon as lliese salnlary mov(!ni(;nts arc arrested or their order distnrbed, (li|)litlieri;i prevails, reaehit)j^ its jionic of prevalence when stat;iia(ion at a relatively hiixh lewl is most complete."^ Accordinii; to Dr. S. M. Copeman,^ there appears to he no direct relation between epidemics and rise or fall of the fjronnd-water, " pro- vided that the strnetur(> and atmosphere of the houses are not affecte;ht of the gronnd-water, ]iarticnlar1y if these have any considerable rang-e." 0)>posed to the views above expressed are the conclnsions based on a most eareful and extensive investigation Iw T)\\ Arthin' Newsliolme,^ of epidemics of diphtheria in all civilized conntries and their incident conditions of rainfall and soil moisture. Dr. Newsholme's eminence as a, skilful interpreter of the value of statistics, and the fact that no such exhaustive iuqniry into this question has ever before been made, entitle his conclusions to more than ordinary weight. Admitting that personal infection is the chief means by wdiich dij^htheria is spread from town to town, and from country to countrv, he summarizes his obser- vations on the relation between rainfall and ground-water and the origin of epidemic diphtheria as follows : " 1. An epidemic of iliphtheria never originates, in the towns and countries in which I have been able to collect facts, when thei'e has been a series of years in which each year's rainfall is above the average amount. " 2. An epidemic of diphtheria never originates or continues in a wet year (/. c, a year in which the total annual rainfall is materially * Notter and Firth, Treatise on Tlypiene, 189(>, p. 463. ^ Stevenson and ^tnrpliy. Treatise" on Hygiene, 1802, Vol. I., p. 338. 3 The Origin and Spread of randeniic l>iphtheria, Loudon, 189S. 348 THE SOIL. above the average amount), uiiles?^ this wet year follows on two or more drv years imnxediately preceding- it. " 3. The epidemics of dij)htheria, for which accurate data are avail- able, have all originated in dry years (/. c, years in Mhich the total annual rainfall is materially below the average anionnt). " 4. The greatest and most extensive epidemics of diphtheria have occurred when there have been four or five consecutive dry years, the epidemic sometimes starting near the beginning of this series, at other times not until near its end. "5. Dry years imply low ground-water, and we find, therefore, in the years of epidemic diphtheria that the ground- water is exceptionally low. The exact variations in the ground-water which most favor epi- demic (hphtheria cannot, with the data to hand, as yet be stated ; but it is probable that when this is cleared up it will become clear why in exceptional years which have a deficient rainfall epidemic diphtheria is either absent or but slight." It has often been pointed out that local soil conditions causing dampness of habitations even in dry years, such dampness, for instance, as obtains in houses built over wet impervious clays, conduce to out- breaks of diphtheria in the dwellers therein ; but, as is well known, such dampness acts as a very important depressant of' the vital forces, and prepares the mucous membranes of the respiratory tract for the favor- able reception of specific organisms of various kinds. Malaria. — It has ever been held that the most intimate relation exists between the soil and malaria, especially prominent in districts abounding in marsh lauds. It has been noticed repeatedly that in malarious countries the upturning and excavation of wet or damp soil are commonly followed by the occurrence of the disease among the laborers so engaged ; that infection is more common among those who go about at night, and especially among those who sleep out-of-doors ; and that the draining of marsh lands is often followed by the disap- pearance of the disease. All of these facts are compatible with the theory of transmission by mosquitoes, and it is now accepted generally that malaria is connected with soil conditions only in so far as the latter permit the breeding of the specific mosquitoes. (See Chapter XII.) Yellow Fever. — There is no evidence of connection between the soil and outbreaks of yellow fever, although for many years such a relation was assumed to exist. The work of American investigators has proved this disease, also, to be mosquito-borne. Tetanus and Malignant (Edema. — It is well known that the organisms of these two diseases are found very commonly in most garden soils, in road dust, and in soil in general which has been en- riched by the addition of decomposing organic matter. But in spite of the fact that opportunity for infection through abrasions, cuts, and wounds of the hands, feet, and other parts is a matter of daily occur- rence with a large proportion of the people, these diseases are compara- tively uncommon. They are noticed most commonly in cases of severe SOI I J Ai\l) niS/'JASK MU injiiricH, hiicIi jis ('ompoiiiid (nK^tiircH, and in Hlinllcrinfr wounds diif to ((xplo.sive.s. A('r.()vd\\\y^ to .some uiilliorilics inoculation ol bporcH uloiw, i.S witllOUl, ('(Ircl, Am nniisnal luiinlKT of (!aH(;.s of t(l;uins is notinr-d in varioiiH local- ilics in (his connlry aflcr (jvcry annii;il cclchrafion of I Mdc|icndcnc<; Day, diK; (liiiclly to wonnds (taiiscd hy cannon-crackers and Idank c;ir- lridfi,(!S lired in toy pistols. In ilic followinfjj ot where, two years previously, a coav, dead of the disease, had been buried at a depth of over two meters, a depth not ordinarily reached by earthworms in their burrowing. Therefore, it seems most likely that fresh outbreaks among cattle grazing on fields where others have died and have been buried are due not to the buried organisms, but to those which in one way or an- 1 The Joninal of the American Medioal Association, Sept. 8, 1910, p. S65. - Mittlieikuigeu aus dem kaiserlicheu Gesundheitsamte, ISSl. 350 THE SOIL. other, from the blood or dejecta of former oases, have beeu de])osited on the surface. Tlie question as to wlietlier pathogenic micro-organisms can be brought to the snrlace by vegetables and deiH)sited upon their stems and leaves in the })rocess of growth has been investigated recently by llendinger and Nouri.' These observers used in their experiments B. jirodigiosus, B. anthraeis, B. typhosus, and B. choleras. In the first experiment a large box was filled Avith earth with fur- rows dejnvssed 10 or 12 centimeters below the ordinary level. The box was untler observation from August to December, was open, but it was not exposed to sun or rain. Radishes, potatoes, peas, and beans planted in the box were irrigated every second day in the furrows with water contaminated with cultures of typhoid, cholera, anthrax, and B. prodigiosus. From time to time the whole surface of the; box was sprinkled, without especial care, with tap water. When the plant had grown sufficiently, specimens of the stems and leaves were taken at a height of from 2 to 20 centimeters and tested for the above-named organisms. B. prodigiosus alone was found, and that upon only one of ten leaves. In the second experiment wheat grains and radish seeds were planted 2 centimeters deep. Immediately after planting, the soil was watered with cultures of the same organisms. After the plants had grown sufficiently, cultures were again made from the leaves and stems, and the bacillus of anthrax was found twice out of eight times and the Bacillus prodigiosus four out of ten times. In the third experiment peas and beans were soaked in the above cultures and then planted 5 centimeters deep. B. prodigiosus was found twice out of six times and bacillus of anthrax once out of six times on the leaves and stems. In the fourth experiment, wheat, radish seeds, peas, and beans were placed in wet absorbent cotton and later were moistened with the above- named cultures. Bacillus of anthrax was found on the leaves 25 days after inoculation and B. ^jrodigiosus 30 days after inoculation. No typhoid bacilli or cholera bacilli were found, although they persisted in the wet cotton. In the foregoing experiments it is apparent that typhoid and cholera organisms do not tend to appear on the stems and leaves of plants if the soil in which those plants are j)laced is artificially infected. If they have any tendency to be present on the leaves, they are apparently killed off by exposure to air and light. These experiments, however, would seem to show tliat animals might be infected with anthrax by eating vegetable matter growing from polluted soils. Uncinariasis. — The disease which stands forth pre-eminently as a true soil-disease, concerning whose etiology there is no dispute, is un- cinariasis or hook-worm disease, known also as ankylostomiasis, miners' ausemia, brickmakers' disease, Egy})tian chlorosis, and St. Gothard tunnel disease. It was first brought to public notice in 1879 by Per_ 1 Compt. rend. Soc. de biol., Par., 1910, LXVJIL, 105-107. ,S'0//. ANI> n/Sh'ASK .">'>! roiK'.ilo, wlio invcHl.i};:i.l((l (lie ('|ti<' IIk; |>;ir;i ili A hIciiIohIoiiiuiii ihioih- rude, wliioli is ;i worm iilxml linlf .m imli in l< ii^tli, wliicli allaclics itsciir, ,soni(!(-iin(!S in ciKH-itiKiis iniinlx r.-, Id llif \ illi ul' the ii|i|mt |i<)r-li<»ri of (lio HtiiJill itilcsliiK!, tliroii^li which ;i coii.sl.inl, (h;iin is made <»ii lhra/il, K^y|>l, India, and varions parts of Europe, and os|)(!eialIy in mining districts and brickfields, whence lh(! names '' miiuM-s' aiia'tnia" and " brielvinaUers' disease." In 1 1K)0, Dr. Bailey K. Ashlord ' mad(; known its presence! in (he West Indies and brought it to notice as i\\v. (-aiise o(" \\u: ti-npic;d ana'tnia, which, in Porto liieo, causes o;r(;at mis(!ry and an enormous d(ath-rat<;; and in 1902, Dr. (Jharles Wardell Stilc^s- announcied thai, in some j)ftrts of the Soutb, it. is (lie most (common disease of" man, and (hat it is more prevalent on the farms and planfations of the sand district (han in the mining districts. Stiles discovered that, in this country, it is due U) a species of ankylostomuni, not before described and not found in the Old World, which differs in some imj)ortant res[)ects from An/:i/fo.s(o- muni duodiiude {^Unciiiaria daodcmdis), but produces the same eflecLs. This parasite he named Uncinaria Americana. Shortly after this announcement by Stiles, Harris ^ reported that a study of malaria in Southern Georgia and Florida, in a region where profound atuemia is most common, proved that, insfead of malaria, he had to deal \vi(h uncinariasis, the sufferers showing generally no malaria jtarasites, but being almost invariably infested with hook-worms. In I'JOo, Ashford and King* declared uncinariasis to be the great scourge of fully 90 per cent, of the agricultural laboring classes (about 600,000 jx-rsons) of Porto Rico. As an indication of its jn-evalenee in the South, the ex- perience of Dr. L. M. Warfield '^ is of great interest. He examined 60 boys, inmates of an orphanage near Savannah, and found that no fewer than 48 were infested. Dr. Claude A, Smith,® speaking of its prevalence in the Smith, says : " It seems as though the entire country was literally saturated with it. It is found on the highlands as well as on the lowlands, and on the mountains as well as on the seaboard." Within recent years the disease has been found to exist in many parts of Europe (England, Belghnii, Hungary, Germany), where its presence never before was suspected, but the victims have been chiefly miners, and the disease has been regarded as peculiar to coal-mining and other underground occupations. The fact that this is no more the case in Europe than in tins country is shown by the observations of ' New York Medical Journal, April 14, 1900. 2 Public Health Reports, October 24, 1902. ' American Medicine, November 15, 1902. * Ibidem, September 5, 1903. ^ Ibidem, January 9, 1904. •^ Journal of the American Medical Association, August 27, 1904. 352 THE SOIL. the Drs. Ibcrer/ who exaniinod large numbers of peasant lads, who never had ANorked in the mines, but \\\\o, nevertheless, yielded in many instances large numbers of the parasites, which fact leads to the con- clusion that the disease is endemic on the farms. Many of these young men after an absence of 3 years, during which time they were doing military service, were found to be still infested ; but they had, nevertheless, suti'ered in no way in consequence. Of the miners ex- amined, no less than 94 per cent, yielded the parasites, and yet no more than one-fourth were even temporarily incapacitated. So long ago as 1895 the disease was declared by ThornhilP to be far more serious in India, Assam, and Ceylon than cholera, on account of the vast number of people affected and the aggregate direct and in- direct mortality. He called attention to the fact that, instead of uncin- ariasis, ana?mia, debility, dropsy, malarial cachexia, and diarrhoea were given as diagnoses. This is of especial interest when we read that, in the district studied by him, Harris has shown that most cases of malaria prove to be uncinariasis. The disease is essentially one of the poor, and its spread is due to the habit of discharging feces upon the surface of the ground. The eggs of the parasite are produced in great numbers and escape with the feces. Deposited on moist soil, they hatch in about 24 hours, and the embryos, after twice shedding their skin, are ready in from 4 to 5 weeks to infest man. Baker ^ accounts for the prevalence of the disease by the habits of the people where it is most common. They live without regard to ordinary sanitation ; they are dirty in their habits ; they discharge their feces wherever they happen to be ; they eat with dirty hands, and often eat the dirt itself. Ash- ford and King say that, in the parts of Porto Rico where the disease prevails, there are practically no privy vaults, and a bit of soil as large as a ]iea may contain as many as 50 larvae. While it is generally accepted that the chief portal of infection is the mouth, to which the parasites are conveyed on food contaminated by dirty fingers or by dirty dishes, or on unwashed vegetables or fruits likely to be spattered with mud, or perhaps in muddy water, there appears to be ground for the belief that a large jiroportion of cases are due to infection of the skin. The first to assert that the parasites can reach the intestine through the skin was Looss,* who rubbed the larvae into the backs of puppies and later found that the animals contained the parasites within their intestines. Boycott and Haldane^ believe that infection can occur through the skin, and Smith ^ appears to have proved it. He bound some earth containing 4-day-old larvae to a man's wrist and allowed it to remain in contact for 1 hour. Almost at once the spot began to itch and 1 Miincliener mediciniscbe Wochenschrift, 1903, No. 22, p. 992. ' Indian Medical Gazette, September, 1895, p. 339. 3 British Medical Journal, March 28, 1903. * Centralblatt fur Bakteriologie, etc., 1. Abt. XXIX., p. 733; XXXIII., Orig., p. 330. » .Joui'nal of Tropical Hygiene, January 1, 1903. ^ Journal of the American Medical Association, August 27, 1904. SOIIj AJSD JJJ,SJ'JA,SK .'i.O.'i tiii^Io. 'I^Ik; Htools, wliir communication ' Ik; asscifcd that ^ronnd-iteli is the most common disease in tlic SdulJi, due lo I lie habit of ^oinj^ barefoot; and Wai'licihP stat(;s that of tix; l-S boys in whom he fonnd the para- site!, hi f^av(! a history of" i^ronnd-itch. \\ arhcld sn/.'-^resL-, lio\v(;v(;r, that. th(' way in vvhi<-h the patients with ^ronnd-itch beeorru; inf'eeled internally is very simple : that tli(;y scratch their i'cet and break the vesicles and thus ^ci, |||(. embryos on thc^ir finders, by which they arc conv(!y(!d to tJu; mouth. J>nt, howciver it lia])j)ens, the infectiii}^ material comes from tin; soil. Nicholson and ]{an kin,'' also, are of the opinion that t:;roun(l-itc.h is the most imjxtrtant factor in the transmis- sion of uncmiariasis. Thiiy have noted that where there is no ground- iteh there is little or no uncinariasis, and that where one is c|>|»), likewise of metal, provided with a number of outlet tubes (c), at regular intervals, preferably of 5 or 10 cm. The lower end of B fits tightly into the up]ier end of ^t, and the joint is made impervious to water by means of adhesive plaster, sealing-wax, or other suitable material. The soil within the lower cylinder is kept in place, and its surface kept intact, by means of a FiQ. 24. Apparatus for determination of permeability of soil to water. superimposed disk of gauze or coarse cloth. The outlet tubes, provided with cocks, serve to maintain a constant level, and, therefore, a constant pressure of water as desired. Water is admitted in a constant stream to the cylinder through its upper end, by means of a rubber tube con- nected with a water faucet. If it be desired to employ the highest pressure obtainable with the apparatus, all the corks of the outlet tubes, except the upper one, are kept in place. In this case, the pressure would be expressed by the distance l)etween the top of the soil under investigation and the uppermost outlet, through which the excess of EX AM /NAT/ON Oh' SOILS. S-Of) water from (he faiu'ct is ;ill<»\v(viii<^ tlic cork of I lie corrcHpoiMlin^ oiillft, wliirh iJniH Ix^cotiK'H (Jic, (•(lliiciil,. WliJilf'Vcr- llic licij.rlit, iii:iiii(:iiiM(l, if. \h n(! water ceases to y Hiiciion of air froiri flic soil iitid f lir(»ii;^li flu; wlndc apparatii-. As flic air cincrtrcs froin flic iiilcf, fiihc oC flic al)S(irj)lioii apparafiis, if j)aHH(*( upward in flu; foriri of hiihhics fliroii^li flic rca^n-iif, to uliicli if ^ivcH uj) its (ionldiif, of (X)^. 'flic reason lor iirereiiin;/ tlie Liilhed fiihc Ih tliJit; (!a(!li l)iil)l)l(' of air in ils jiassa^c froiii one hull) fo flic ucxf ahovc is nc(;ossarily l)ron<^lif, info niorf; infiniale and iiroJon^r'-'i cf^niixcA wifli ilic rcajj:;cnf, flian is flic cas(; when flic |ilaiii iiciil fiihe is eriiploycd, for Fki. 2r>. -■6 -0' 01 w>. ^^^q,^°^ ,c:^'-^' '?f*^' Apparatus for determination of CO3 in soil air. here the air bubbles pass quickly aloug the upper inner surface of the tube, and are not so exposed to the reagent as to lose all the contained COj. For this reason, it is necessaiy to dra^v the air through a second, and, perhaps, a series of such tubes, but one bulbed tube as pictured above is sufficient. The water from the aspirator is measured carefully, and its amount indicates the volume of air that has been sucked up (^ut of the soil to take its ]>lace. When the desired amount has been acted upon, the stopcock of the aspirator is closed, and the reagent in the absorj)tion 362 THE SOIL. tube is transferred quickly to a glass-stoppered bottle of suitable size. From this point, the determination is the same as described in the chapter on Air. Bacteriological Examination of Soil. The bacteriological examination of the soil requires necessarily an intimate acqnaiutiince with bacteriological technique, a subject beyond the scope of tliis work. It may be stated brieily that many of the organisms that inhabit the soil )nay be isolated by adding small por- tions of the sifted .sample to liqueticd gelatin and then plating, or by sprinkling over the surface of a nutrient medium, or by shaking with distilled water and transferring thence to the proper media. The many anaerobic forms require, of course, the special treatment of their class, and some of them may be grown on ordinary culture media ; but many of the saprophytes, notably the nitrifying organisms, cannot be isolated by the ordinary methods. For the details involved in the separation and identification of the numerous varieties of soil organisms, the reader is referred to the standard works on bacteriology. Oil A VT\:\l I V. WATER. A.R8()liii'rioi,^' pure wnicf, tlint is, tlic siil)>t;iiK;(! (•(»rn|)f»s('(l wliolly oC hydrojrcn ;iii(l uxyircii, ;iii(l rcin'csciilcd liv tlic Hyinhiil 11./), is never fniiiid ill luiiiii'c, ;ui ailKMKJAI. (IIAIIACTICIUSTICS O/' WATIH:. 'MM or |)()(;I«!iH wilJi no si(l(! oiitN^tH, lli<: j^ronn(l-wat,<'r in in fioriHfant l;it;aiiic mailer in condmial ion, and have in e<(nsc(|U('iic(' a brownish tint, whic^h, hy reason of \cry slow o.xidiilion, may |)ersi.st for a lon^ time. (yolor (kM'ivcd othei'wise tlian from contact with vc^ctabh,' matter \H accompanied usually by more or less turbidity. Absence of (;olor i.s not a si<;n of pnrity, for polhiled \vat<'rs may be quite free i'vum it ; nor is its prescMuu' an indication of unfitness for donicstic use. Reaction. — 'J'he dissolved carb(»n dioxide in water tends to ^ive it a slightly acid reaetion, but most potable Avaters arc veiy faintly alkaline to delicate indicators, owini!; to mimite amounts of alkaline carbonates. Ivain-waters, espeeially in the vicinity of cities and larj^e towns, are generally slightly acid on account of impurities of the atmosphere, arising from combustion. Peaty waters also are slightly acid on account of organic acids produced by the action of the peeidiar bacteria existing in jwat. River-waters in mining districts often contain con- siderable amounts of free mineral acids. Odor. — Pure water has no odor, but good surface-waters containing coloring matters \va\q more or less odor, wln'ch is especially marked on heating. It is generally suggestive of vegetable matter, and may be characterized variously as grassy, peaty, etc., according to the impres- sion produced. Such odors may persist even on long boiling, while those due to dissolved gases will disappear quickly on heating. Many otherwise good surftice- waters are particularly prone to the develoi)- ment of disagreeable odors attributable to minute living organisms. The subject has been studied very extensively by Mr. Gary X. Calkins,^ who states that odors in drinking-waters " may be produced by the putrefactive deeom})osition of the body plasm through the agency of bacteria, and by the excretion of certain products of growth, or by the liberation of products by the physical disintegration of the body or breaking down of the enclosing cell walls. These three causes give rises to three classes of odors, as follows : (1) odors of chemical or putrefactive decomposition, (2) odors of growth, and (3) odors of physical disintegration." The group of plants popularly known as '• blue-green algje " (ScJiizophi/cav) is a very common cause of the well-known "pig-pen" and " grassv " odors so frequently observed in shallow, stagnant, and relatively warm waters. Certain of the DiatomaciW frequently cause serious trouble by imparting aromatic (geranium) and fishy otlors 1 Eepoit of the State Board of Health of ^Massachusetts; for 1892, p. Sob. 24 370 WATER. aud disiigreeiible taste. Of these, the most prominent is AsterioneUa fonnosd, tuiind very (.'oiuiuonly in large ponds and reservoirs of surface- water, and ^rowing with especial luxuriance in open reservoirs of ground- water. According to \Vlii[)[)le and Jackson,' 3000 astcrionella per cc. of water niav, under favorable conditions, impart an odor easily recog- nized by the consumer. Several species of Uroglcna, commoidy, but according io G. T. Moore,- perhaps incorrectly, classed with the h\Jii- sorid, cause nuich trouble by the liberation, durhig disintegration, of oil globules which impart fishy, oily odors and tastes. These oil globules are yielded by many other varieties of water organisms. A>'liile sewage matters impart mouldy or musty odors to water, it should not be inferred that these odors are of themselves indicative of sewage pollution, for good surface-waters sometimes acquire them on standing. Sometimes it will be noticed that water on long boiling not only con- tinues to evolve a vegetable odor, but gives it oti' in greater intensity. This is true ])articnlarly of waters rich in algaj. If they are first filt- ered, the odor will not be given off on boiling. But other waters may continue to evolve odors even after filtration. Peaty waters, for in- stance, often persist in yielding odor on long boiling, and this is not affected in any ^vay by filtration. Waters containing products of physi- cal disintegration and various other substances also are not influenced by filtration. Odors which disappear on boiling may develop again after a time if their cause is not removed ; if, however, the matters from which they are derived are no longer present, the odor will not return. Some most troublesome odors are known to be the results of decay. The public supply of Boston was, in 1878, seriously affected in this way, and gave off an odor which was likened to that of cucumbers. This was investigated by Professor Ira Remsen, who found the cause to be decomposition of a fresh-water sponge. Water sometimes contains sulphuretted hydrogen from reduction of sulphates by bacterial action, and sometimes mixtures of pro(hicts of organic decomposition which suggest that gas. Very marked and most offensive odors are due often to the presence of dead animals, such as toads and mice in wells, and, when they arise, the remedy is ob- vious. Some wells become stagnant at the bottom, and if organic matter is present, it may cause foul odor, suggestive of dead animals, by putrefaction in the absence of a sufficient supply of dissolved oxygen. Stagnation may be prevented by connecting the piunp nearer the b(jttom, or by filling up the unnecessary space with clean gravel and sand. Odors in water are not necessarily indicative of danger to health, but distinctly unpleasant ones are quite sufficient as a discpialification, on account of the repugnance which tlieir use for drinking and other domestic purposes would cause. On the other hand, as in the case of ' Journal of the New England Water-Works Association, September, 1899. ' American Journal of Pliarniacy, January, I'JOO. SUBSTANd/y FOUND NORMALLY IN WATHIt. '371 color, al>H(!iic.(! is iiol- iiit(; (listinelly, hut it should lu; reniiirked lli;i( (lie senses of (;ist<' and smell arc often inlluenced iiiieonseiously hy (he sense of sijj:h(, and colored water KU[)i)<)sed (o h.i\c both odor and taste may, if drunk in the dark, give no impression of either. IJadly taslino' water, whether diinji:erous or not, is ohjeetionahlc on the same _a,'ronn(ls as mentioned under odor. Not only is ahsenee of bad taste no evidence of purity, hut it is well known tha( waters con- taining the j)roducts of oxidation of .sewage are often remarkable for unusual pdatability. Substances Found Normally in Water. These include : 1. Gases in solution. 2. Organic matters in solution and in suspension. 3. Mineral matters in solution and in suspension. 1. Gases. — First in importance is air. Strictly speaking, water con- tains no air as such, but only the constituents of air, for the oxygen and nitrogen, dissolved by water, are not present in the same propor- tion in wliieh they exist in the atmosphere. In salt water, the varia- tions in their proportions are less wide. We shall, however, consider the two gases as air. The dissolved oxygen is the important element. One hundred volumes of water at 15° C. will dissolve nearly 3 vol- umes of oxygen ('2.99), and at 20°, 2.80 volumes, and it is not alto- gether removed by boiling. The amount of oxygen in solution is fairly constant in waters of uniform composition freely exposed to the atmosphere, but when they receive additions of sewage and other oxidizable matters they begin to lose it. River-waters may thus show notable ditferences in the amount of dissolved oxygen present in sam]iles taken above, within, and below towns situated on their banks. The Thames and the Seine, for in- stance, show this in a remarkable degree. The progressive diminution is due to the constant access of organic matter, which undergoes oxida- tion at the expense of the dissolved oxygen. AMien a river-water is deprived of its dissolved oxygen in this manner, or by reason of chemical changes due to the inflow of sewage from manufacturing 372 WATER. establishments, containing compounds — ferrous, for instance — having a strong- affinity for oxygen, fish life cannot be supported. Absence of fish in polluted streams is due much more to diminution of dissolved oxvgen than to tlie poisonous effects of organic sewage. Aeration of water is intluenced very largely by the dust which falls into it, for each particle carries ^vith it more or less adherent air, as mav readily ,be seen when one drops small particles into water and observes their descent. Aeration of water proceeds to great depths, as is shown by chemical analysis of samples of water obtained by deep sounding, and also by the fact that great numbers of organisms which require oxygen for their respiration are found far beneath the surface ; but water at 40 and 50 feet below the surfiice may contain no oxygen. Water from deep wells is very commonly free from dissolved oxygen, because of abstraction by compounds of iron or manganese, org*auic matters, and other substances. The presence of considerable dissolved oxygen in water leads to beneficial changes in the organic matter present. Diminished oxygen permits the development of low forms of vegetable life, which fre- quently give rise to unpleasant tastes and odors. Their growth is inhibited by a large degree of aeration, and their disagreeable effects are thereby prevented. Carbon Dioxide. — The carbon dioxide contained in water is derived largely from the atmosphere, and in great part from the soil, where it is present in abundance. Its amount in any water depends upon a number of circumstances : upon the amount carried in by rain and dust, the character of the soil, and the extent of oxidation of organic matter occurring in the interstices. It is greatest in amount at great depths, and it may constitute almost the entire content of dissolved gases. It has been calculated that the ocean contains about ten times as much as the entire atmosphere. 2. Organic Matter. — The organic matters in water are of both ani- mal and vegetable origin, and consist of organisms, products of organic life, and results of disintegration and decomposition. The animal matters include dead and living organisms and dissolved and sus- pended products of animal life and decay, such as albuminous sub- stances, urea, and tissues. In the tropics and subtropics, ova and young of various parasites are common. Ordinarily our interest in organic matter from animal sources is confined to the products of human life as represented by sewage, which may contain the exciting causes of specific diseases (see Bacteria in Water, page 379). Vege- table organic matter exists as living and dead organisms and tissues in suspension, soluble and suspended substances given off during life, and soluble matters extracted by the water after death. The vegetal)le organisms are represented by very numerous species of microscopic plants, which act beneficially by absorbing the products of organic decomposition for their growth, but which may, on the other hand, under favorable conditions, become the source of much trouble by over-abundant growth, disintegration, and decay. They may prop- SUBSTANCES FOUND NORMALLY TN WATER. ?>1'?> (;rly !)(' ro^ardod ;ih iionmil ciiiistitiicnls of .siirr;irc-\v:i(«'rs, for they aro jilwJiyH |)r('M<;n(. in sik^Ii, :iihI, inorcKvcr, (Jicy r of which iiii^-rcdients it fixes in the; form of f(?rrie oxide in th(! <;(^laiin()us sheath of its filanunits, which thcrehy become y(!lh)W, yellow brown, or brown in color. Jt (;auses great annoyance by the rapidity with whieh it grows in water-pipes, the lumen of which is not infrequently completely occluded, 'i'his may occur more readily where the surface prestiuts roughness and imperfections, to which thf! growths may attiieh themselves. When the lilaments an; broken off and become disseminated through the water, the latter is rendered unfit for laundiy use on account of the iron-rust. Sometimes, it gives rise to disagree- able odors and an iidvy tiiste. It may be very troublesome within the tubes of driven wells, or in the reservoirs, as well as in the distributing pipes. Sometimes, it may be seen in large aggregated masses floating about on the surface of stored water. By its extensive growth in pipes, it may seriously affect a whole public supply. The presence of living forms, either vegetable or animal, indicates that the water contains at least whatever food materials are necessary for their existence, but not necessarily that these are in excess. Algae, for instance, require mineralized nitrogenous matter (nitrates), and other substances ; fungi suggest the presence of carbohydrates, pro- teids, and mineral substances common to domestic sewage ; infusoria suggest organic decomposition. Dissolved vegetable matters ordinarily amount to but little in weight. Even in some very broMU waters, whose appearance would suggest large amonuts, they may be present to the extent of not more than 1 or 2 parts in 100,000. The organic matters, both animal and vegetable, which are of inter- est to the sanitarian, consist chiefly of carbon, hydrogen, oxygen, and nitrogen, with, in many cases, small amounts of phosphorus and sul- phur. In the process of decomposition, which owes its inception, progress, and completion to bacterial activity, the carbon is combined with oxygen to form carbon dioxide, and the hydrogen unites in part with nitrogen to form ammonia, the presence of whieh in water in- dicates that the process of decomposition is under way. In its turn, as will be shown later, the ammonia is converted eventually to nitric acid, whieh unites with bases to form nitrates. Ammonia. — From the standpoint of sanitary significance, ammonia in water is of prime importance. Only under very unusual conditions does it exist in the form of hvdmte, but usuallv as chloride or car- 374 WATER. bonate. "We speak of it eoiuinonly as free ammo))i(i, for, on boiling the water, these salts are tU'coniposed and the aniinonia is expelled in the steam. Among the direct sources of annnonia in water is rain, which brings it down out of the atmosphere in varying amounts according to location. Rain always contains it, but more is present in that of thickly ])opulated districts than in the open country. In one instance, reported by Drown,' it was found to the large extent of 0.05G4 in 100,000. Its presence, however, in surface- and ground- waters is due for the most part to decomposition of nitrogenous organic matter. It is not abundant in ordinary unpolluted Avaters, but is present often to a very considerable extent in that of deep driven wells. Here its origin is not always clear ; in some cases it is supposed to be referable to coal deposits, in others to reduction of accumulated nitrates. Under ordinary conditions in surface-waters, ammonia, after conver- sion to nitrates, is absorbed very quickly by groM'iug vegetation, and the more active the conversion and the growth, the greater the apjn'o- priation. For this reason, water from the same source will often show less on analysis in summer than in winter. But activity of vegetation is not responsible alone for this difference in amount, for in the case of large bodies of water, as lakes and ponds, the rate of movement of the water has great influence. During the warmer months, when the upper layers are warmer and consequently lighter than the lower, the latter become necessarily stagnant and stratified. The ammonia which accumulates in these lower strata does not, therefore, come to the sur- face until cold weather approaches. Then the upper layers become more dense and tend toward the bottom, causing a displacement of the lower layers toward the surface and general uniform mixing of the entire volume of water. Another element in the stirring up of the water of ponds and lakes is the action of wind, which, ho>vcvcr, does not extend beyond twenty feet. Still another influence to be con- sidered is that of springs at the bottom and sides, which tend to keep the water in motion. In the case of flowing rivers, the water is of comparatively uniform composition at all depths. Ammonia is very characteristic of sewage pollution, the oxidation of which yields it in abundance under conditions which do not permit it to be rapidly oxidized to nitric acid. Ammonia as it occurs in drinking-water is of itself incapable of producing harmful effects. Its amount, however, is of greater or lesser significance according to circumstances : that from clean and properly stored rain-water is of far less significance than that from other waters. In the one, it may be considerable in amount and mean but little ; in others, it is usually evidence of deconqiosition of organic matter. Its amount in good water is not large, and on account of oxidation and absorption by vegetable growth it does not accumulate. And even in sewage-polluted waters, when vegetation is active, oxidation and ^ Massachusetts State Board of Health : Report on Water Sui^ply and Sewerage. Boston, 1890. Part 1, p. 562. HJJi;STAN richci- in nitrletely reduced. \Vhen nitrites are ]iresent at the expense of the nitrates l)y the action of metallic surfaces, lead and iron, for example, the metals themselves are present in at least detectable traces. 3. Mineral Matters. — Chlorine as common salt is a normal constit- uent of all waters. Kaiii-water takes it up from the air in small traces, particularly near the sea coast. In the specimen of rain referred to on page 374 as rich in ammonia, the chlorine content was 0.13 per 100,000, Avhich is much in excess of that found in many inland waters. The amount of chlorine normally present in the water of a district depends on location and other conditions. It is influenced very greatly by proximity to the sea, the air above which contains necessarily more than that at a distance inland. It varies in amount in the same water ■with differences in the amount of rainfall and evaporation, and in the directi(ni of the wind. Chlorine increases du'eetly with the population, and its amount is 378 WATER. . influenced very greatly by a proper system of sewerage which carries the sewage matter, rieii in common salt, beyond the limits of the drain- age area. AVhen its amount rises above the normal of a locality, it is indicative of sewage, though not necessarily of recent pollution. As we have seen, the organic matters become mineralized, and no longer exist in their original form ; but no such change occurs in the chlorides, which remain fixed and unchanged, and they may be the only evidence remaining. Thus a water polluted by sewage may have its organic nitrogen converted to nitrates, and these in turn may be absorbed by vegetable growth ; it may be clear, colorless, odorless, and palatable, free from pathogenic bacteria, and in every way suitable for drinking, but, nevertheless, the chlorine remains as a witness that pollution has occurred in the past. According to Professor Drown, in a general way 4 families, or 20 persons, per square mile will add on an average 0.01 part of chlorine per 100,000 to the water of a district in seasons of average flow, and UK^re in time of drought. Other Mineral Matters. — The total amount of dissolved mineral mat- tor in any drinking-water depends upon the character of the soil with which the water has been in contact, upon the length of time of expos- ure, and upon the amomit of carbon dioxide held in solution. Not even the hardest and most insoluble rocks wholly escape the solvent power of water : no mineral is absolutely insoluble. Silicate of aluminum, which is least acted upon, is soluble to the extent of about 1 part in 200,000. Silicious rocks in general are attacked only very slightly, while limestones are dissolved with comparative ease, and yield con- siderable calcium and magnesium carbonates, especially if the water is rich in free carbon dioxide. Gypsum also is acted upon very freely. Some waters contain very large amounts of mineral matter, derived from deeply situated natural deposits. The Carlsbad springs, for ex- ample, are said to bring annually to the surface enormous amounts of sodium chloride and calcium carbonate, besides 2,500 kilos of calcium fluoride, 600,000 of sodium carbonate, and 11,000,000 of sodium sulphate. Besides the ordinary salts of the alkalies and alkaline earths, most natural waters contain at least very minute amounts of iron. Appre- ciable amounts of iron make water unsuital)le for general domestic and technic purposes. It causes staining of clothes if used in the laundry, and headache, dyspepsia, and constipation if used habitually for drink- ing. It cannot be used for dyeing, and as little as 1 part in 1,000,000 makes it unsuitable for use in bloaeheries. A cpmrter of a grain per gallon is sufficient to impart a distinct chalybeate taste. The permissible total amount of dissolved mineral constituents cannot be stated, but 50 parts in 100,000 are generally held to be excessive. Hardness. — Hardness is the capacity a water has for decomposing soap. It depends on the amount of salts of Mg and Ca in solution, and hence upon the character of the soil with which the water has been nAC'TK/UA IN W A '!■/■: n. ?>70 in c.oui'M'A. W;il('r (Voni ro(;Iout ' Chemiker Zeitung, 1896, p. 65. 380 WATER. two hundred varieties have thus far been described. Tliey may be present in small or in enormously larg-e numbers without being ueces- sarilv of hvgienic significance, although usually their existence in large numbers indicates the presence of an abundance of organic matter, and yet they may thrive and multiply enormously in water containing al- most no organic food materials. Indeed, multiplication occurs more rapidly in pure, than in polluted water, but diminution in number is also more rapid. In impure water, they multiply slowly, but their growth is jiersistent, and, under ordinary natural conditions, sudden marked diminution in number does not occur. The ordiuary water bacteria are found in much greater abundance in surface-waters than in those derived from the soil. Indeed, many observers, including Koch and Fraenkel, have maintained that waters from the unpolluted subsoil are practically sterile. This, however, has been shown by Sedgwick and Prescott ^ to be not the case. Using im- proved methods of investigation, and paying special attention to the nature of their culture media, these observers demonstrated conclusively that wholly unpolluted springs, wells, and tube wells may yield consid- erable numbers of bacteria and sometimes a greater abundance than is contained in some surface-waters. In their paper they state " that the plates are remarkable not only for the slow growth of the species present, but also for the absence of liquefying colonies, and, in many cases, for the abundance of chromogeuic varieties. These facts are especially important as indicating the total absence of contamination by ordinary surface-water, and, as far as they go, they strengthen the con- fidence with which well-protected ground-waters may be regarded as sources of public water supplies." Their conclusions and results have been confirmed a number of times by other competent investigators else- where. Ground-waters, when brought to the surface and exposed to the air, soon become rich in the ordinary forms of bacteria, which find in them the conditions necessary for extraordinarily rapid multi- plication. Surface-waters vary very much m their bacterial content according as the conditions present at any one time favor or retard growth and accessions. Sunshine, influx of food material or of substances inimical to bacterial life, sedimentation, and growth of higher organisms act for or against increase. Suspended matters in their descent carry down with them the bacteria that have gathered upon them or have been entangled by contact. The diminution in their number by this means is more marked in still waters than in rivers with rapid motion. The growth of algffi and other water plants causes diminution by removal of the nutrient materials upon which the bacteria depend, and probably through some other influence not yet discovered. The increase in bacteria, sometimes noticed during the colder months, is explained by Frankland ^ by the fact that in winter much water runs in over the surface from manured fields. ^ Report of the State Board of Health of Massachusetts for 1894, p 435, 2 The Bacterial Purification of Water, London, 1897. iiAuehner ' has shown that the rays of the sun will kill cultLircri of the ty|)hoid haeilliis at a de|)th of nhoiit five feet in four and a half hours, while at double that depth thdr effects are hardly |)erce])til)Ie. While it is true that this orf^^anism survives lon^-r in (!old than in warm weather, it cannot he said delinitelv that the rwi- sou lies in any inherent greater resistance to tin; infiuenee of cold than to that of heat; and, indeed, it .seems more probable that the ex])lauation is to be found in tlie fact that in warm weather tiie goxx- (htions are more favorable to the growth of the con)mon species of water bacteria anIucIi are believed to secrete substances Mhich exert a toxic influence on pathogenic varieties and ciiuse them to disapj^ear. The belief that such toxins are secreted i.s strengthened by the researches of Frankland,^ who shows that waters which do not favor bacterial multiplication are changed in this particular on being ])oiled. He found that, while anthrax spores were nuich diminished in number or actually destroyed in a sliort time in unsterilized water, their numbers were not reduced and their virulence remained unimpaired in sterile water after upward of seven months. These toxic sul^stances are pre- sumably not secreted by all forms of water bacteria, but only ])y certain species which may or may not be present in any given water, and it is regarded as most likely that they are not inimical to the same extent to all varieties of pathogenic bacteria, but that substances harm- less to one kind may act fatally on another. In general, it may lie stated that ]iathogenic bacteria which form spores retain their vitality and virulence longest in any kiud of water. Concerning the significance of 5. coli communis, which is exceedingly- common in drinking-water, there is much difference of opinion. Kruse,^ in 1894, asserted that this organism is so ubiquitous that it cannot be regarded as characteristic of sewage, and in this position he has received the support of a number of other investigtitors, who have ^ Centralblatt frir Rakterioloeio uini rarasitenkunde, XI. \\ 781 '■^ .lonnial of State Modieine, .Tamiarv, ISvU. * &itschrift fiir Hygiene und Iiifectiouskraukheiten XVII., p. 1. 382 WATER. succeeded in isolating the organism from all waters examined, although in many cases it was necessary to employ large volumes of the samples. The committee of the Laboratory Section of the American Public Health Association, to wliieh the question of the significance of B. coli in water supplies was i-eferred, reported ', ii] October, 1903, that, in spite of the fact that numerous investigators have found the organism where it could not directly be traced to sewage or fecal pollution, the colon test of water is a safe index of pollution ; that their number rather than their mere presence should be used as a criterion of recent sewage pollution ; that evidence of the presence of B. coli in a majority of 1 cc. samples should be required for a conclusion that a water is sewage polluted ; and that the examination of large (100-1000 cc.) samples for B. coll should be discouraged (one of five members dis- senting). On tlie question of the desirability of isolating streptococci as well as B. coli, to confirm suspicious evidence of pollution oifered by B. coliy there was no agreement, but great diversity of opinion. According to Clark and Gage,^ of the Lawrence Experiment Station, whose conclusions are based on the results of examination of some 16,000 samples of water from all sources and of more than 2000 miscellaneous samples of shellfish, sea-water, ice, milk, dust, excrement, etc., the colon bacillus, occurring more numerously than all other bacteria in normal sewage, is the most valuable index of sewage. When a considerable number of samples from the same source are examined, 100 cc. samples frequently give more information as to quality than do single cubic centimeter samples. In filtered polluted water, bacterial tests are of greater value than chemical analysis ; and disturbing factors in filtration, shown slightly or not at all by ordinary bacterial counts, are often shown strongly by B. coli tests. WATER SUPPLIES. Immediate sources of water supply comprise : 1. Stored rain. 2. Surface-waters, including rivers, lakes, and gathering basins. 3. Ground-waters, including wells, filter galleries, and springs. 1. STORED RAIN. Where other water is not obtainable, and where the natural water is unfit for drinking or for wasliing and other domestic purposes, stored rain-water is used. If this is collected under proper precautions to prevent the presence of extraneous matters of undesirable character from the receiving area, and properly stored, it constitutes a most wholesome supply. But excepting where rainfall occurs with regu- larity and frequence, the uncertainty of supply, especially in periods of drought, acts as a great drawback. An inch of rainfall is equivalent to 5.61 U. S. gallons per square yard, or 27,152 gallons per acre, but ' Public Health Papers and Reports, XXIX, p. 356. ' Ibidem, jx obG. STOIUJ) ILAIN. 383 only :i SMiiill proporlioii of" lliis Culls ii|)(iii -iiif;u-c> (roof's, (•!,' I'aiii from I'oofs, it is scry necessaiy to insuiH; eleaidi- ness of the su|)pl}', hy allowing- the first (low to run to waste, thcrcl)y avoidiuii,' eonlaniination hy dirt, leaves, l)ird-(lro])pinti's, soot, and (ttlicr maltei's deposited u[)on the roof" and eolleeted in the jxiitt(!rs. A num- ber of automatie devices are in use for the ])urpose of diverting; the iirst washiuj^s away from the eonductors. Af"ter this has been done, they ehani2;e position, so that the subsecjuent fall is saved and stored. rrres^ularity in ])r(H'i|)itation is, as has been remarked above, a serious drawback to reliance upon rain as a sole sup])ly. Partly owin^ to a general belief that great battles, in which large (juantities of explo- sives are used, are eommonly followed by heavy rain, numerous experi- ments have been tried toward breaking drought by discharging power- ful explosives in the u])]ier strata of the atmosphere, but without success. As a, matter of fact, the idea of connection between battles and rainfall is by no means new, and has, indeed, come down from times antedating the use of gunpowder in warfare. Furthermore, in- vt'stigation of government records has shown that the popular belief has no foundation in fact, and that great battles have been as often followed l)y j>eriods of fair weather as by days of storm. Rain-Avater requires no aeration, for in its descent it has absorbed considerable air ; but melted snow and ice should be shaken with air or poured repeatedly from one vessel to another, in order that they mav lose the Hat taste so characteristic of unaerated water. Moreover, their use in the flat condition is believed to conduce to gastric derangement. Snow-water is usually more impure than rain, because the suowflakes, by reason of their larger surface, are more efficient in removing dust and dirt from the air. Cisterns for storage of rain should be so constructed and an*anged as to admit of easy inspection and cleansing. They should be kept covered, so as to exclude dirt and dust of all kinds, insects, mice, and other animals, and to shut off light as well, for the presence of light is an important aid to the development of lower plant fonus. The 384 WA TER. be.-^t materials for their oonstriu'tioii :ire bricks, stone, cement, and slate. Cement makes a good lininii' if one is desired ; mortar, how- ever, is objectionable on account of the solv(>nt power of water upon lime, which will cause progressive increase in hardness. Cisterns should be provided with overflow jiipcs dischai'ging into the o])en air rather than into the house sewer, and their exits should be ])rotected bv wire netting ag-ainst the entrance of leaves and small animals. 2. SURFACE-WATERS. For public supplies, especially of large communities, surface-waters, as rivers, lakes, and collecting basins, are generally more available than ground- waters. Large rivers and lakes are, unfortunately, very connnonly subject to most extensive pollution by sewage of large communities and manu- facturing establishments along their borders, and by the waste products discharged into them from sailing vessels and steamships. Many rivers are subject to progressive increase of pollution by reason of serving as the most convenient receptacle for the sewage of a succession of towns and cities located at intervals from the source to the mouth. Thus, one town takes its water from a point above and discharges its sewage at another place below ; a second, farther down, takes the already contaminated water, and in its turn discharges its sewage at another convenient point, and so on for the rest of the course. On account of the dangers attending the use of such ^vaters, some process of treatment is imperatively demanded to remove the objectionable elements. The different processes available for this work are considered elsewhere. The public mind is being awakened gradually to the wrong practised upon one community by another by the discharge of untreated sewage into what is its only available water supply. In the case of cities located upon the shores of the Great Lakes and other large bodies of fresh water, it is commonly the case that the intake of the water sup- ply is located at no very great distance from the outfall of the main sewers. Smaller rivers and lakes may be subject to the same influences, though in lesser degree ; but, in general, it may be said that these are controlled more easily, especially when they lie wholly within the jurisdiction of a single law-making power. Basins for the collection and storage of rainfall and surface-waters are constructed by throwing a dam across a valley or other convenient depression. Experience has taught, that, even though involving large expenditure, it is best to strip off' the surface layers in order to get rid of all organic matter and vegetation, which, if left in place, may prove fruitful sources of trouble. The water which gathers in them has op- portunity to rid itself of much of its suspended matters by sedimenta- tion, and is more often used without further treatment than otherwise. All surfiee- waters contain more or less active vegetation, and on that account should always be kept exposed to light and air, otherwise (iiio iiyi)- \v.\ Ti'iiiS. 385 \\\v. fniiiiii(! plniiis will die, mii'I in lluir rjcfotiijKtsilirui ^iv*- riM- to iinplcnsiinl. odor, ;i|>|)c;ii";iiif<', ;iihI Iii-Ic. Stoi;i}.M' rc-crvoifH hlioiiM lijivc siiHic-iciiil, (lc|>l li to |ii(\iiil ill*' \\;il-arv to seeiin; protoctioii IVoni pollntion by taking f^reat Inicts ol' land and lly, storage is not ordinarily necessary, the water being obtained oidy as immediately needed or ]nimpelluted. The possibility of contamination after and even at the point of issuance from the ground is too often overlooked. Springs are common to some localities and rare in others of similar contour, their presence or absence being determined by conditions not of the surface, but of the geological formations below. In Figs. 27 and 28 are showu in profile two depressions having the same contour, 25 386 WA TER. but with very cliiferent arrangement of the umlerlyinc; stmta. In Fig. 27 the formation favors the outeropping of springs ; in Fig. 28 the opposite is the case. Fig. 27. Fig. 28. Wells may be classed as dug, driven, and bored. Sometimes they are divided also into deep and shallow ; but these terms as a basis of classification are of doubtful utility, since there can be no general agree- ment as to the line of division between them, and because of the absence of any necessarily distinctive peculiarities in the water yielded by ordinary wells of different depths. It is not uncommon to meet with general statements that the water of shallow wells is dangerous to health, and should, tlierefore, be avoided, and that all shallow wells should be condemned and filled. As will be seen, however, shallow wells are not necessarily dangerous, nor are deep ones always safe by reason of mere depth. By some writers, the term deep is applied to wells which obtain their water from below the first impervious stratum, through and l^eyond which they have been extended ; while the term shallow is applied to tliose which draw from what we designate as the ground-water ; tliat is, that collected over the stratum above mentioned, regardless of the depth at which it lies. With these meanings, it follows that a shallow well may extend farther downward than another classed as deep. The ordinary dug well is a hole dug in the soil down as far as is necessary to reach water, and lined with brick or stone, or, better, with earthenware tubes of large diameter made for the purpose in short lengths with bevelled edges to secure good joints. All brick and stone linings should be well bedded in cement, except near the bottom^ and should be faced with the same material throughout their upper part. The impervious lining is necessary for the prevention of the entrance of surface washings ; but it is very generally the case, in some parts of (IILOIINI) WA TKIIS. Wl tli(! v, wMier lo tJi(! surface, |)iinip>- should be us«'d, and not biKikets woi'lciiinj^ a well (or tlu! piirpoHc «»(' iii- crcilHin^ tlu! Hiipply soiiMlirncs lias llic vci y oppoHiti! cH'ce^t,, and may <^V(!n caiiHo it to niii pfacti«';illy di'y. Suppose, lor example, \\\c irn- p(!rvi<»iis lay(!r is underlaid hy a lliiek strattuu o(" coarse j^ravel, and in tlu! pr()(!(!KH of d(!epenin}^ tli(! w<:ll this stratuiu is entend : instead o(" an incr(!iiHC in tlic su|i|)ly, it then may liap|)en (liat the water (lowing into the well (ind.s a niady exit downward hy the force of (gravity into the inli^rstiecrt of the; gravel, anl .Srr/-,, >-r,tirjn ;„ A/ //'. ',. 'Vd '/j. 'Ma /,'///„ ',///k Geological formation favorable to the obtaining of water by means of artesian wells. is materially warmer than that from the upper subsoil. Distinctly hot water from deep sources is rarely fit for ordinary domestic purposes, because of the large amount of mineral matters present in solution by reason of the greater solvent power of water when hot than when cold. Thus they acquire an abundance of salts, which, taken into the body, influence its functions and act as medicines. The presence of organic matters is of importance on account of their reducing power. The sulphuretted hydrogen so common to mineral springs is due to the action of these matters on sulphates. Irrespective of the changes wrought by increased temperature, the water yielded by this class of wells varies very widely in charac^ ter. It may bear no resemblance whatever to the other waters of the same district, nor is there any reason why it should, for the con- ditions at the surface and at points hundreds of feet below are quite (JlLOIINh-WA'I'FJiS. 391 (liircr'ciit.. M(tr(;()V(!r, one ciiiiiiot I. now Iidw (";ir llic \v;il(;. or Willi M's (Voin lour siirli wells sunk williin tin- limits oCtlic city of Boston to f mueh larjrer than if it be clayey and close. If extensively jHimju-d, the well will drain a p;reat(n' area than if the demands Ix; moderate ; in fact, the amount of water removed by j)umpiiio; has a greater influence in deter- mining the draina<;(! area than mei'c depth. Hut other thinj^s bc-ing equal, the nature of the water-bearing stratum determines the distance to which the measurable influence of pumping is felt. Pollution of Wells. — In general, it may be stated that, as between wells of diil'erent de]>ths, the shallower an; more subject to ])o]Iution than the deeper, because of the fact that the latter have the advantage (»f the greater opportunity for perfect filtration through the soil. ]5ut both are subject to pollution by unoxidized matters which enter the soil below the upper few feet in which the nitrifying organisms already referred to are found, as, for instance, from leaching cesspools and leak- ing drains. It is a practice only too common, even on estates of con- siderable size, where the excuse of limited area cannot obtain, to locate the well and the cesspool very near together. To avoid the necessity of having to remove the contents of the cesspool as occasion demands when this receptacle is made water-tight, and to avoid the exjx-nse attending this kind of construction, the bottom is generally left o|ien, so that the house sewage may drain away into the surrounding soil. Connection between the cesspool and the well may take considerable time or may occur quickly, but, once established, contamination goes on uninterruptedly. Often it happens that the direction of the flow of filth through the soil is wholly away from the well, and contamina- tion may never occur ; but this is a point that can never be determined in advance. It is a common belief that, if the well is located in higher ground than the cesspool, there can be no danger of pollution of its water. This, however, is a most fallacious proposition, for it is not so much the location of the outlet of the well that determines the possibility of pollution, as the relative position of the cesspool and the point where the water enters the well. In Fig. 32 is illusti-ated the manner in which the supply yielded to a pmup placed at a point considerably 392 WATER. above the location of the cesspool is ptilluted directly by the liquid tilth issuing; tVoui the latter. Again, the geological formation may be such that a cesspool on higher ground than the nearby well will have no iutiueuce on the purity of the water. Thus, a ledge of rock may crop up between them, as shown in Fig. 33, and divert the How of polluting matters away from the well. Fig. 32. CessPool- How a well located on high ground may be polluted by the contents of a cesspool lower down. In locating wells and cesspools, property owners not infrequently lose sight of the fact that, while they can govern the disposition of the surface of their respective estates, the conditions that obtain in the soil below are quite beyond their control. In consequence, they may attempt to guard against pollution of their own water supplies by their own excretory products, without regarding the possibility of contami- nation by those of their neighbors. Fig. 33. How a cesspool located on high ground may fail to pollute a well lower down. The water of newly dug wells is often of such a character as to lead to the perhaps false conclusion that it is probably polluted by sewage. It is generally turbid, and may, on analysis, yield results which, in case the analyst has not full information concerning it, may seem to warrant a condemnatory report. It may yield figures indicating a high content of organic matters, which may disappear as the use of the (J no UNI) - \VA 'i'i:iis. '.V.i'.\ w.'i,i(r l)(!(',()rn(!S ((Hliihlislu^d. I( tuny <'V«'ii sliow iiiKlcni.'ililc cvi'hricc of (li(! pn^scrKU! of liiniiMri wmsIcs, fur" llio,-c r■|l^^'l{_r(•(l in tin- •lijrj.'iii^'; and tlu) Htoiiiii^ '"iiy I"' I'liiic iiil(i(-(<'(| III llic coiiiplcli*!!) (»f tin; \v<»rk tliari in tlu! iMirfdci, piifily of llic ,sii|i|)ly, and niay Ik- di>inclin<(| to \ru u\> to lll(i SUrliuH! (or llic |)lll'|iOSC oC relieving; (he cull- oI'lKitlirc. ( )n ;i|| ;ir-- counls, (Ji(!r('(orc, il is licllcr (u auail llic rcsidts of a later cxatninatiori, (iiaii l.o <'oii(lciiiii and aliaiidoii loo lia.-tily a i^Mjiply, wliicli, within a wliort, t.irn(!, may |)i'ovc lo he ol" cxccjitional |iurily. Very (l(M'p wells may Ixcoiik; l)a(>: A well hoi'ed 500 Icct. into red sandstone drained, thron^h fiHSuros, all the sliallow wells in llic \iciiiily. 'l"lie.-c licirif^ of no ii.sr; as wells, wore then ntili/ed as cesspools, ann of the salts. In the latter case, removal a short distance back- ward obviates the dilticulty. That the watei* derived from a filter gallery is not due to percolation from the river along which it lies, is farther proved by the fact of dif- ference iu composition, and especially iu hardness. Classification of Waters from the Sanitary Standpoint. From the standpoint of wholesomeness, waters may be divided into two classes : 1. Those free from sewage contamination. 2. Those polluted by sewage. Unpolluted waters are not necessarily suitable for domestic use, pre- senting as they do, wide variations in character. They may be clear, colorless, odorless, and palatable, and contain but little organic and mineral matter ; or they may have high color, turbidity, disagreeable odor and taste, and a high content of dissolved and suspended sub- stances. A water which, by reason of appearance, odor, and taste, due, for instance, to luxuriant growth of algae or other forms of life, is repugnant to the senses, should not be recommended for use, although incapable of producing a specific disease. Such an one requires no chemical analysis to determine its fitness, the evidence of the senses being quite sufficient. Unpolluted waters free from such qualities as render them repug- nant to the senses, and of low content of organic and mineral matters, are suitable for general purposes without regard to their classification as surface- or soil-waters. But, in general, it is held commonly that an unpolluted soft ground-water of good composition is preferable to one of surface origin. Polluted waters may be divided into two classes, according as the pollution is direct or indirect. Direct pollution by sewage is, it is hardly necessary to say, of prime importance, because of the danger of transmission of specific diseases and of lowering the physiological re- sistance of the system. But even direct pollution may be productive of no harmful results, provided sufficient time elapses between the entrance of the sewage at a given point and the use of the water at a distance to permit of the disposal of the noxious elements by natural processes. Thus, a volume of sewage entering the upper part of a large system of public supply may not reach the distributing pipes for several months, during which time its dangerous qualities will have disappeared. Notwithstanding this fact, however, direct pollution of drinking-water should be prevented by all means available, on account of possible risk, and even on aesthetic grounds alone. Indirect pollution is of far less importance than direct. In indirect ai.Assii'icA'rioN of watf/is. '.Vjr, polliillori ilic or^iuuc. riiiillcrH oC (lir- Hc\VJif^<', irirliidiri^' iKirfi-ria, an; Tilt- (•r('<\ lliioii^li llic Koil, ill wlilfJi tlicy an- licid Itar-k nircliaiiically and in(»i-(' or less cotriplclcly oxidi/.cd IxCiiir llif ()lliil imi, no (ixcd I'nic can Ix- ;.'iv<'ii : cadi ca-c irm.sl. \h\ iiidj:;cd ac(M»rdinj^ lo ils cii'cMunsfanccs. Tlic hoil :i^ a wliolc has (Miorriioiis capax^ily ("or pnrilyin^ walcr of its containcrl or^'^anic suhstaiKU'S and bacteria, hot li hy rnc.clianical retention an«I hy r)xidatiori [)roc(!SH(\s sv.i in motion by the ha(!tcria which iidmliit it. lint all hoilw have not this power in an c((nal dej!;re(!, an to ^vlu)se acti^m nnich of the changes noted by Emmerich and Brunner Mere undoubtedly due. The important effect of temperature on the ability of streams to purify themselves was brought out by Ruediger at the Annual Meeting of the American Public Health Association in 11)10. Kuediger found that colon bacilli and typhoid bacilli disap})eared from river water much more rapidly iu summer than in winter. In producing this result the most important factor was found to be microscopic jilants and other organisms, which, in their growth, manufactured dialyzable substances harmful to the bacillus coli and the bacillus typhosus. These micro- scopic plants do not grow at a temperature below 0° C. Furthermore, in the winter time, the water being covered with snow and ice, the bactericidal action of the sun's rays becomes ineffective. These facts accord with the experience that typhoid epidemics, due to polluted water supjilies, and occurring in northern cities, frequently take place in the winter time. Such a winter epidemic, in fact, occurred at Minneapolis in 1909. Methods of Purification. — The methods employed for the purifica- tion of water embrace : 1. Chemical treatment. 2. Boiling and distillation. 3. Filtration. 1. Chemical treatment is employed to cause the formation of insolu- ble precipitates, which settle out and entangle suspended matters, in- cluding bacteria, in their descent. Alum, for instance, added to the extent of a quarter of a grain to a grain per gallon of natural water containing a moderate amount of CaCOg, is decomposed, and forms an insoluble gelatinous hydrate, which combines with the organic matters imparting color and set- tles out as a flocculent precipitate, which entangles the sus])ended matters, including the bacteria. The sulphuric acid, set free by the decomposition of the salt, unites with the lime or other bases present, and is thus neutralized, and the calcium sulphate thus formed carries down sus]iendcd matters in the same manner. If an excess of alum is added, it will necessarily appear in the purified water, and be objection- able on account of its effect on the system, and in the bath and in washing. In case of deficiency in CaC03, liuie-water sometimes is supplied, and identical results obtained. The addition of freshly precipitated alumina serves the purpose equally well, and avoids the presence of the sulphuric acid resulting from the decomposition of alum. Alum removes practically all the bacteria, as has been proved by V. and A. Babes,^ Professor E. Ray Lankester, and others. The use of alum in the purification of water is not of recent origin : it was de- 1 Centralblatt fur Bakteriologie und Parasitenkunde, 1902, XII., p. 45. I'Ullll'K'A'riOS' <>!■■ W'A'I'Kll. '.V.)'.) K(;ril)('(| ;iH curly as IS.'JO hy l''cli,\ d'A red,' who iiit. liimc-Wiilcr or milk of lime, .idilcd (o \\;itcr coiilaiiiiiiji- calciimi <'ar- l)()iiai<^ held in soliilioii l)\' (miIioii dii»\idc, (•;iiis(;,s iirciripitation tt\ Jli<; ioriiKU' l»y iiiiilint;' wllli (lif I.iIIit. Ii llm- willidravvH the wjlvcnt frotri ii<'tiv(! service, causes |)reci|)il;il imi (if llial wliicli was licid in solution, and, becoinin^ ilscIC coiiverled loan iii.-.olnl)lc snhsluticc, is prcr-ipiljiled. Ho a d(nil)i(! |)reci|)i(alioii occurs. IJiil walcr lliiiH treated i- nol n«'ccH- Ha,rily liiniled in ils eliaiincs lo a removal of its cxcchh of c;ilciiiiii <-jir- honaie, lor, in (lie |)re(^i|»i(aiioii of tliis siibstjinc*!, conHJdtirahlc otluT mailer may he ca,ri'ied down meelianieally, and hacfcria arc Icsntiicd decidedly in nnmhci". l*(!rmani;analc of |tolassimn is nsed more or less, particularly in \v<;ll.s in India dui'in^ the prevalenc(! of cliolera cpidi'inics. Enough is addcid to secure a slight piid< tinge, which indicates a slight excess. This acts as an oxidizing ageiil wilh good results. Vi)V cxam|»le, I )r. P. VV. O'doi-man" lelates that during an (tiithreak at Midnapore, the number of cases, 117, was supposed to have been kept down by its use. These oeeiu'red in all |»arts of the town, excepting in the Kiirf)- peau (juarter and at tlu; jail. The li)rmer used water which was filtered or boiled and tiltered, and at the jail especial care was taken of the water supj)ly. Forty-six public and ju'ivate wells were disinl'eeted with the salt, and the outbreak thereupon ceased. An ounce or ounce and a half or more, according to the size of the well, Mas diss(»]ved in a bucket, poured into the well, and stirred about. If after half an hour the water showed a red tinge, it was considered that enough had been added ; if not, more was added until a tinge was seen. Accord- ing to Hankin,^ enough of the salt to insure a reddish tint lasting twenty-foiu' hours should be added ; lint care should be taken not to add so much that fish, frogs, and turtles, put into wells to keeji tlie water clean, are killed and the water spoiled by their ])utrefaction. Dhingra* states that this method can be relied upon only under cer- tain conditions, and even then its action is not continuous. The agent nuist exjiiMid itself first in oxidizing organic matter and nitrites before attacking oi'ganisms, Avhich, for their destruction, require it in fairlv strong solution. He believes the method to be fallacious in theory ^ defective in technic, and impossible of practical aj^plieation. The hypochlorite treatment of public water supplies has received new impetus during the last few years. The value of the mi-thod was recog- nized, to be sure, as early as 1888 by the late Thomas M. Drown, but up to 1908 the use of hypochlorites had not received serious consideration. Clark and Gagc,^ in a paper entitled " Disinfection as an Adjunct to Water Purification," state that " the action of hypochlorites and per- manganates in water are quite similar ; both are oxidizing agents, and 1 Note relative :i la elarification de I'ean du Nil, et en gi^n^ral des eaux contenant des snbstanees terreuses en suspension. Annales d'Hygiene publique, IV., p. 375. '^ Indian Medieal Gazette, Jidv, 1890. 3 Ibid., .July, ISIUI ■ < British Medieal Journal, Aug. 17, 1901. * Journal of tlie New England Water ^Vorks Atjsoeiation, 1909, p. 302. 400 WATER it is to this oxidation that their disinfectino: action is dno. Unlike copper .sidts, neither of them retains its identity lor any length of time in the Ayater, and the slight increase in the ]>ernianent hardness cansed by the amounts of bleach ordinarily used in water puritication, or the small traces of manganese which may remain in solution after perman- ganate treatment, probably haye no physiological action upon the con- sumer." ^ " AA'hen bleach (a double salt of calcium hypochlorite and calcium chloride) is used in combination with sulphate of alumina in mechanical filtration, a satisfactory bacterial remoyal may be obtained at nmch less expense for chemicals than when sulphate of alumina is used alone. In such a process the disinfection occurs in the coagulation basin before the water reaches the filter, and subsequent filtration introduces a factor of safety which greatly adds to the elfectiye purification of the water, aod greatly reduces the chances of the occasional failure of the process. Experiments showed that an effluent of better quality l)acterially was obtained by the use of about 0.9 grain sulphate of alumina and about 0.7 grain of soda per gallon in combination with bleaching powder equiyalent to 0.11 part per 100,000 available chlorine than when nearly double the amounts of sulphate of alumina and soda were used without the disinfectant." These writers state, furthermore, that no form of disinfection should be practised without competent bacteriological supervision, for " such disinfection would tend to introduce a feeling of false security, which, in case of the failure of the process, at any time, might result in serious consequences to the health of the consumers. For this reason alone, if for no other, disinfection should be followed by filtration, which would tend to reduce the chances of failure." Johnson - states the following to be the advantages and disadvantages of the use of hypochlorites in connection with water purification : Advantages of the Process. 1. Substantially complete destruction of objectionable bacteria, par- ticularly those of intestinal origin. 2. Reliability and ease of application of the chemical, together with the small variation in the required dose. 3. Total al^sence of poisonous features, either in the chemical product, as applied to the water, or in any of its resulting decom])osition products. 4. Merely nominal cost of the chemical and its application. 5. Speed of reaction, making unnecessary any substantial arrange- ments as to basins other than storage facilities. 6. Sulistantial saving in the cost of coagulation of waters that are of sufficiently unsatisfactory appearance to require clarification or filtration. 7. Permitting rates of filtration materially in excess of those pos- sible where high bacterial efficiency is required of the filtration process in the absence of sterilization. ^ .Journal of the New England Waterworks Association, 1909, p. 318. 2 Engineering Record, Sept. 17, 1910. rillUFKIATION Oh' WATKIi. ^()\ H. |{,[)rccial)l<' amonnt'- of" <'olor or dissc*) vcfl vof!;otal)I(! slain. T). Inability to remove! orifjinie matter a|)|)n!eial>l y. (5. Inahilily to remove swiunpy tastes or odors. 7. Jnahility to remove creosote tastes or odors eominjr from the cleaning of stills used in the destriK'tiv; the fact that the commercial ])r()diiet usually contains a little free ({uicklimc, which reduces slin'htly the carbonic acid in the water. 9. Difficulties encountered in a])plyin<^ this process, except with tlic greatest care, to waters which contain substantial quantities of reducing agents or com])ounds capable of oxidation, such as nitrites and unoxi- dized iron. Johnson and other experts also believe that ''the use of hypochlor- ites cannot be considered in the light of a substitute for filtration. . . . As an adjunct to filtration jirocesses it has a distinct field of applica- bility, for at a moderate cost it is feasible to obtain water practically above suspicion ; and, furthermore, there is l)rought about a substantial economy in the first cost of a filtration ])lant. It is made possible by the use of higher rates of filtration than are ordinarily used, and the required filter area may also be reduced. It also effects a substantial economy in the cost of operation. Ijromine also has its advocates as a chemical purifier, both on a small and on a large scale. Schumburg' reconnnends a process which is said to kill in five minutes nearly all of the ordiuarj' bacteria and all pathogenic organisms found in water. He uses a solution of 20 parts each of bromine and potassic bromide in lOO of water, 1 cc. of whicli suffices to sterilize 5 liters of Spree water. After five minutes' contact, the bromine is neutralized with ammonia, and the result is a clear, tasteless, sterile water. Very hard waters and grossly polluted river and marsh waters require larger amounts, because of the presence of lime salts in the former and of ammonia in the latter, whi^-h ct^m- bine with the bromine before it has opportunity to act as a germicide. AVith such waters it is necessary to add enough of the solution to produce a yellow tinge which will persist at least half a minute. In 1 Deutsche medicinische Wocheusohrift, March 4, 1S97. 26 402 TT^J TER. anv case, Avbatevor the amount of the hroniine sohition used, an etiual volume of 9 jiei- cent, ammonia water should be added. (In a later eomnumie:iti(»n, sod'uuh sulphite is reeommended.) This ]>roees8 is reeommended partieularly for use in the army, and in the tropies, for ships' supplies, and for individual use in times of epidemics. A kilo- gram of bromine is said to suffice to sterilize 16,000 liters of ordinary water. In practice, however, the process has not met with a large measure of success. Schiider^ has tried the scheme, and finds it unre- liable. It was tested in the Soudan Expedition in 1898, but the difficulties attending its use were enough to lead to its abandonment. Treatment with metallic iron in the form of borings and punchings is employed in a number of ]>laces in Europe with most successfid results. The best known of the processes in which this agent is emjiloyed is that of Anderson, in wdiich the water is delivered into long iron cylinders, on the inner surface of which are curved partial dia])hragms which, as the a]>paratus slowly revolves, carry upward the jiieces of iron, which fill about a tenth of the volume of the cylinder, and cause them to shower constantly downward through the water in its passage. The carbon dioxide in the water attacks the iron and forms ferrous carbonate, which, when the water is discharged into the oi)en air, becomes oxidized and converted to ferric hydrate. This floc- culent matter entangles much of the organic matters, including the bacteria, and then the whole is passed through sand filters, the effluent from which is very pure and practically sterile. The process is unneces- sarily expensive, involving as it does, in addition to the first cost of the ])lant, considerable outlay for ]io\ver and otlier items, while the same results in the end may be obtained by the more simple process of sand filtration alone. Moreover, it appears that with peaty waters, the organic constituents of which form soluble compounds ^^'ith the iron, the results are unsatisfactor}-. The use of ozone has Ijcen recommended as a very efficient method of sterilizing drinking-water, and experiments on a large scale have yielded favorable results. Experimenting on very small quantities with a Siemens-Halske apparatus, Weyl^ found that 2.3 milligrams of ozone were sufficient to destroy 99 per cent, of the bacteria contained in 200 cc. of water from the Tegel Lake. AVith 3 and 4 milligrams, he obtained complete sterilization of 0.5 liter of water containing 6,000 bacteria to the cc. For purification on a large scale, the impure water is caused to percolate through a tower filled with pebbles, through which the ozonized air passes upward. The Siemens-Halske apparatus used will produce 20 grams of ozone in an hour. The bacteria are reduced at least 99 per cent, and the percentage of organic matter is greatly diminished, but the process is at present very imperfect, for more than 70 per cent, of the ozone produced is lost. The ozonized water, although free from odor, has an unpleasant taste, and with many persons its use causes derangement of the stomach. This fault neces- sitates further electi'olytic treatment with aluminum electrodes, Nvhereby 1 Zeitschrifl fiir Hygiene und Infectionskrunkheiten, XXXVII. (1901), p. 307. 3 Centralblatt fiir Bakteriologie, XXVI. l-UniFICATIOS OF WA'IKli. 403 jllmiiimiin liy(lr';il(! is luinicd ;iii. Ii/jj/ioxiis is «lc.stroyc«| in lliiiiv, niid />'. c/m/crtr in ten, niinnles. ('(»nh';iry to llie slatein<'iit tlial ilie a,t;-eiil ini|»ai-(s an a 7 'F.JIS. 405 I'Kl. S."). cojil, .s}K>njjj(!, ^roimd }^1;ihh, wool, (Ihj.iriil oiIki' -iiltstaiu'cs \vlii(;li htraiti out tli(! viHil)l(! ,Mii,s|icii(lc(l iiiaf,lcf.-> iiol, a wliii hctlcr fliaii tlic KiriipK; fiaiiiKtl ha^ in coMiiiioii use in New lOnulanfl and clsfwlicn' a (jiiartcr oC a(!('iilnry ati:;o. 'rix'y pcrniil, IIk; passage ol" a j^ood ,s(rc;irn, and fliis fiu-t iiscK" is proof o(" llicif incllicicncy as hatttcria (ihci-, for any niat«rial Hndicac^njly coarsi; to |icniiil rapid |)aHsa^(; of \va(-|niidcd inaftcrs as hartcria. Most of the materials used hccdinc vliorl time, and in (M)ns<'(|n('nc(! the water is richer in hacteria on issuing than it wa« before eiiti'aiiee. 'l'heoreli<'all\-, animal ehareoal, on aceonnt^ of its oxidi/.iiiu a<'liiiii, -hmild he ;iii ideal llllcrino; medimn, and at lir>l it will re- mo\'e a: Iari2;e |)i*opor(ion (»f t he hacteria and more or less of any eolorinji; matters, lint \-ery shortly it he(M)mes fonl ; tlu; calcinm phosjihate which it (contains is of great assistance In t he growth of hae.teiaa, ; (^leaning is impossihle, anougies are not equal in efficiency, for Horrocks ' has succeeded in gi\)wing B. typhosus through the walls of the latter. He attributes this result to the larger size of the lacunar spaces and to the consequently diminished immobilizing and devitalizing influences. Since the shortest time required for the bacilli to traverse the bougie is four days, sterilization by means of boiling water should be carried out every three days, in order to insure complete safety In general, the requirements of a satisfactory domestic filter may be stated as follows : It should yield a sufficient supply of clear, colorless water, free from taste derived from the filter itself; should arrest all bacteria and their spores ; and should be simple in construction, and offi'red at a low price. Thus far, those made on the principle of the Chamberland-Pasteur filter have met these requirements best. Their introduction into use in the French army in 1889 was followed within two years by a reduction of more than 50 per cent, in the number of cases of typhoid fever occurring therein. Filtration of Public Supplies. Filtration on a large scale is accomplished by the aid of fine sand in filter beds of proper construction, which act both mechanically and biologically. The first beds of which we have accurate knowledge were those constructed by Simpson in London, in the year 1829, which were intended primarily for the removal of dirt and other sus- pended matters causing turbidity. The process was regarded at that time as a purely mechanical one, and though in course of time this kind of filtering medium came into very extensive use, it was gen- erally believed that as carried on there was no marked chemical change in the water, and that what did occur was attributable to oxi- dation of organic matter by air in the interstices of the sand. This was, indeed, the view held generally up to the time when the extensive researches begun by the State Board of Health of Massachusetts in the summer of 1887 proved the great influence of biological agencies, al- though it had been shown by Meade Bolton, Herseus, Plaggc, Pros- kauer, and others, that filtration removed all but a trifling percentage 1 British Medical Journal, June 15, 1901, p. 1471. FIl/niATION O/'' I'UIlhK! Sl'I'f'fJf'IS. 407 of (ni(;n)-or;i'-tcfi;i, cxcrl*-*! .'-omc inlliiciK'*- on Lli(i uirioiml- <»(" (Iw! iisii;il consl idiciils ol' \v;ilcr. Al(li<»iii;li smihI nil I'liiioii (if piihlic supplies i,~ o(" (•()iiip;ir;itiv(!ly r<'f;i!iit ori^'iii, ils use (or iii(li\'i(!neatli tlu; stontas were laid ordinary drain J)ipes, throiij^^h \vhi(;li the* liltererl water waH discharn-ed. As th(! top layers of sand became c\(>^^<:<\, they were seraped and renewed. The beds of I he present day are c<)nstru<;t(!d on V(!ry similar lin(!S. They are virliially immense tanks of varying size, sha|)e, and eonstruetion. The walls an; som(!tirnes vertical, but more often slo|)in<;-, sometimes bnill, of stone or concrete, and sometimes con- sisting t)f ordinary embankment. Upon the j)aved bottom of a bed is laid a system of ])erforated or disjointed drain pipes leading to a cen- tral culvert or well, from which the filtered product is drawn. Alxn-e the drains are successive layers of coarse gravel, fine gravel, coarse Fig. 36. FINE SAN D OARSE SAND GRAVEL COARSE GRAVEL DRAIN PIPES Partial vertical section of one form of filter bed. sand, and, at the top, one of tine sand from three to five feet in dejith. (See Fig. 36.) The tine sand is sharp-grained in character, such as is obtainable at the seashore, and it should not contain clay or other material of similar minuteness of particle ; if present, such should be removed completely by thorough washing. As to the size of the sand parti- cles, it may be stated generally that the finer the grain, the better the eflHuent ; but, it should be added, the more rapidly it lx>comes clogged and the more frequently it needs to be scraped off, and finally, the more ditiieult it is to wash for future use. With the finest sands, the bacteria are removed absolutely, but filtration proceeds so slowly that * De luilitis in custris sanitate tuenda, auctore Luca Aiitouio Portio, Vienna, 16S5. 408 WATER. their use is not practicable. The most effective si/e of orain is a matter on which opinions differ ; but whatever the size adopted, it is imjiortant that care be taken to insure uniformity. It is stated variously to be from a fifth to one millimeter in diameter, that is, the diameter of a sphere in volume equal to tiiat of the grain without regard to the shape of the latter. The higher figure is the one adopted by the authorities at Haniburg. Before the water is applied to the bed, it may be advisable — and if it is from a turbid river, it will be necessary — to allow it to stand several days in a settling basin or reservoir, in order that the sus- pended matters may subside, and thus the too rapid clogging of the interstices of the sand with mud be prevented or retarded. Observ- ance of this precaution will result in lessened necessity of frequent cleaning. Not only are the suspended matters lessened in amount, but organic matters in solution may be destroyed more or less com- pletely by bacterial action, and the bacteria, too, may be diminished in number by being carried down with the settling matters with which they are in contact, and by the death of the less hardy varieties. In the case of waters from ponds and lakes, the preliminary sedimenta- tion proceeds in situ and the settling tank is not needed. The water is delivered continuously at the surface of the bed by devices automatically regulated, and percolates downward through the various layers of" sand and gravel to the outlet pipes. Except with very fine sands, the first water of the effluent is not much, if any, purer than the original, but in a short time a sediment layer is formed on the surface and a slimy algoid growth occurs. This super- ficial layer acts both mechanically and by its contained bacteria to cause the removal and oxidation of organic matter and destruction of bacteria. The resulting effluent is quite pure and practically sterile. The Lawrence filter, for instance, removes more than 97.50 per cent, of the organisms present in the water as delivered, and the reduction is still more marked at the house service pipes, where 99.17 per cent. is recorded, the increase in purification being supposedly due to the fact that their necessary food material has been removed, and hence they cannot long survive. At Hamburg, Altona, Stuttgart, London, and other places, the reduction in bacteria is about the same as at Lawrence, All organic matters are not acted upon to the same extent during filtration ; some are decomposed very rapidly and mineralized, while others are attacked so slowly that complete removal during the short period elapsing between entrance and exit is often quite impossible. This latter class includes the brown coloring matters so commonly present in surface-waters. These are very stable compounds : they persist during long storage and are nitrified but slowly. In the proc- ess of chemical treatment with alum, however, they are coagulated and removed very quickly. The slime layer, mud layer, or " schmutzdecke," is believed by some to constitute the sole actual filtering medium, the sand beneath acting only as a means of support. But experiments conducted at Lawrence and elsewhere show that this is not true, and that if the FILTRATION OF /'ll/UJf Sfir/'LUX 409 ffr(.'at(!st (;!ir(' lo l)c <'X('rcisc(| nol Id di-liirl* I lie imnK fr| oil' wiliioiil lruclion and mincr- ali/alion of the ori;;inie matters are of the sanio chiHH of nitrifying or{' the l)actcria is not directly dne to the process of nitrification, for it, lian been proved thai a, \'ery marked increa.-e in the pinccHH i.s not no(x;.S- sarily accom|)ani('d by any dimimition in (he inmd)er of orfrjmisms whi(Oi manatee, to pass lhron<;h to the drains. It i- |)OKsibl(' that the snpposcd relation of cause and vWcvA, is merely a coincidence of con- ditions, that is, that the conditions favorable to nitrification arc unfavorable to the vitality of the ordinary bacteria. Jt is also jkw- sible that thron<;'h nitrification the latter arc deprived of at least ])art of the food materials necessary to their continued existence' and mul- tiplication. Nitrillcation sometimes ceasca suddenly after it has been proceeding for a long' time at a proper rate, and then, after an interval, begins again without apjiarcnt reason. One explanation oflcred is that the process begins only when a certain amount of nitrogenous matter has accumulated within the interstices, that it then proceeds until the store is consumed, and that pending a further accumulation the process lapses. In winter it does not begin again until the tem- ]HM-ature of the effluent reaches at least 39° F., but after it is once started it is unaffected by a fall to 35°. The most favorable tem- peratures for the process are those of the hot summer months. As to the rate of filtration, it is im])ortant that, whatever the rate, it shall be uniform all over the filter. It has been proved by the Massa- chusetts State Board of Health that 2,000,000 g-allons jx-r day can be filtered through each acre of filter bed with the removal of sul)stantial1y all the bacteria originally present. The Imperial Board of Health of Germauv fixes 2,500,000 gallons per acre as the maximum amount per- missible. Koch's three rules of filtration are that the rate of down- ward movement should not exceed 100 millimeters an hour, that the filtrate of each section should be examined daily while the bed is at work, and that filtered water containing more than 100 bacteria to the cc. should not be allowed to enter the pure water reservoir, but should be rejected or refiltered. The bacteriological test is much superior to chemical analysis for watching the efficiency of a filter, and a simple count is quite sulficient without attempting to identify the species. When the filter begins to discharge slowly on account of the extent of the algoid growth at the surface, it is not safe to increase the press- 410 WATER. ure imdiily bv flooding the bed with an increased deptli of water, for, as was shown by an experience at Berlin, such a procedure may force the bacteria, ■\vhicii havi' accunuilated hirgvly in the meshes of the growth, down through the tiker at such a rate tliat they are not de- stroyed by the usual agencies. In this case the water level was raised two feet,- with the result thtit tlic poition of the city which was supplied with the water of that ])artieuhir bed was visited by an epidennc of tvphoid fever. The sjime sort of accident occurred at Altona some vcars ago, when, a year after successfully going through the cholera epidemic which devastated the neighboring city of Hamburg so extcn- siveU', a defect in the filter beds was followed by an outbreak of cholera, which disease had then died out in Hamburg. When the sediment layer becomes so thick and dense that with the maximum pressure allowable the required amount of water liiils to pass, it becomes necessary to scrape otf the inch or so that has formed, and then to proceed as though the bed were new. It will require, as a rule, several days for the formation of a new sediment layer, and until it is well developed the effluent should either be rejected or pumped back. The frequency with which a bed will require to be scraped depends npon individual circumstances, such as the size of the grains, the character of the water as applied, the rate of movement, the season of the year. The removal of the top is not difhcult. It is quite compact and distinct from the sand beneath it, and is readily pared off with shovels or other tools. Successive clean- ings may take place without replacement of the sand, until the depth of the tiltering material is reduced to about 15 inches, but not below 12. The scraped-otf sand may be washed thoroughly in a machine for the pur])ose until a sample in a beaker yields no turbidity to clean water, and it may then be stored until needed for future application. Experiments have been tried repeatedly in Massachusetts, Berlin, and elsewhere in sterilizing sand by boiling it in water or otherwise subjecting it to high temperatures, and then determining its cfiiciency. The results have proved invariably that more bacteria are found in the filtrate than in the original water, and this is ex])lained by the suppo- sition that the bacteria that enter find in the cooked organic matter a food supply most favorable to enormous multiplication, and that the bacteria in the washed sand are necessary for the destruction of organic matter and of some of the varieties of water bacteria. During and immediately after the scraping process, the bed is neces- sarily out of use, and, therefore, it is necessary, in order to insure con- tinuous filtration, to have a number of separate beds, and to scrape them in turn. In this way, while one is out of use, the others can carry on the work. In cold weather, owing to increased viscosity of the water, the rate of filtration is less than in the warmer months. In very cold climates, the formation of thick ice makes proper cleansing of the surface im- possible ; and imperfect scraping causes imperfect filtration. The re- moval of the ice augments considerably the cost of maintenance, and this item alone is one of sufiHcient importance to warrant the expense FII/riL\Tlf)N OF I'lJlUJC SdJ'I'fj/J'JS. 411 (tf (5(»v((rin^ tli(! I)i(ls. I'.iil aside Ironi cost, tlu; clVicu-wy of (Ik; jiroy l)iin;_dng it a,l)i>iit. tliat tlu; bed is owirwoi'ketl in those plaees which are still |»er\ioiin. The application of water to the, Iro/en sni'faee thaws the ice slowly and iine(|iially, and when; the liltei' is active, it is doin^ the work of its fro/en iieinhhorin^- areas. »Scra|)in!j,' of a l)ed l)clow the ico cake is pcirfbrniod with a machine wliich runs helwceii the sand and the ice, cuts the layer and receives it in a, ha*;' as liist as it is removed. It is (h'ay'LTcd from sidi- to side with- out breaking' the ice above it. Covering a filter is aoiis in anntlier direction, for by the exchision of liglit, growths of alg;e are inhibited, and tliere is, there- fore, k'ss need of frequent cleaning. On the other hand, open filters get the l^enefit of the sterilizing in- fluence of direct sunlight, but this is more than offset by tiie promotion of luxuriant growth of algae and other microscopic ])lants in the warmer months. It is sometimes hardlv possible to keeji filters in good work- ing order in summer owing t^) these growths, which clog the inter.-tices very (piiekly and cause diminished efficiency just at a time when the demand for water is greatest. The coincidence of greater demand and more frequent cleaning does not permit of sufficient intervals of rest after the conijiletion of the scrajiing process. In what is known as ''intermittent filtration," the filter l)cted by the authorities of a number of cities in Europe. "Mechanical Filtration." — In some places, particularly in the United States, the water supply is treated in what are known as mechanical filters, of which there are a number of varieties, all based on a common principle. Such a machine consists chiefly of an iron or wooden cylinder filled with rather coarse sand or crushed quartz, through which the water passes by gravity or is driven under pressure at a much faster rate — from 50 to 150 times faster than it moves in a bed. To take the place of the sediment layer which forms in the latter, an artificial film is produced by the use of alum as a coagulant. This is formed quickly and serves the same purpose, though not with the same thoroughness. The filter is called mechanical only because power and mechanical devices are employed in regulating the rate, pressure, the application of the alum solution, and the raking and shaking of the sand in the process of cleaning, which process it is necessary to carry out at short intervals. Instead of removing the top layer, the whole body of sand is thoroughly agitated and washed. Filtered water is pumped through from below for five or ten minutes, and the sand layer is agitated by revolving rakes or by compressed air introduced from below. The process is not suited to all water supplies, but for the highly colored and turbid waters so common in the South and West it is particularly well adapted, and is cheaper, more efficient, and more easily managed than filtration through beds of sand. With careful man- agement, upward of 99 per cent, of bacteria are removed. Within the last two years the combination of mechanical filtration and chemical disinfection with hypochlorites has been found to be more efficient than either process alone, and has been recommended by com- petent authorities. Destruction of Algae. For the destruction of overgrowths of alga), Moore and Kellerman^ recommend the use of copper sulphate in extreme dilution (about 1 part of the crystals to 4 or 5 millions of water). In the practical appli- cation of this agent to ponds or reservoirs, the crystals are placed in ^ U. S. Department of Agriculture, Bureau of Plant Industry, Bulletin 64. IlKMOVAL OF IIMIDNKSS. 413 ^iiiiiiy s!i(;l;its, wliicli (r;iv(;r,s(; tin; .'ircu in conmitrif lines Ironi 2."> to 10 i'cft apuri. 'V\\v. process lias hccn tiiid in \;nions plru-r-H witli roHults varyinj;' IVoin (;ornpl('L(! snc.ccss (<> nttcr I'lilinc . In some iriHtiincf;.-, the (l(!Hi,rn(!( as well a- Im.~- (if (ime which the nse of hard walers in washinjx entails, and oC the injnry to which hoileis and liol-uater pipes arc sul)jo(!t from their action, it often becomes neeessaiy (o :i|»|»ly some remedy wherehy the de^-ree (»f hard- ness may be lessened. This may be accomplished by tin; aid of heat or by the addition of chemicals. J'xiiling, as wo have scon, drives off the contained cai'boii dioxide and canses precipitation of the earbf)nat<:« which ha\e been held in solntion by this afz;en(, bnt it lia.s no effeet on the salts which canse the permanent hardness. I-'or nse on a large scale I'or publico snpplies, this means is liardly applicable, on account of the cost of ])lani and of fuel ; but for domestic purposes the co.st is com])aratively slight, in that the fuel uecessaiy in cooking may be utilized coincidently for the purpose of lieating water. For the chemical treatment of hard waters, the first process devised was that of Clark, patented in 1841. This process is based upon the affinity of caustic lime for carbon dioxide, Avith which it forms the practically insoluble carbonate. On the addition of lime water to water containing chalk and mag- nesium carbonate held in solution by carb(Mi dioxide, the reaction occurs, and a double precijiitation of the carbonates present and of that formed is brought about. Tlic process is veiy ecouomiciil so far as cost of material is concerned, in that a few cents' Avorth of lime will remove an amount of hardness which will decompose many dollars' worth of soaj). Lime water, however, does not affect the chlorides and sulphates, and hence, like boiling, reduces only the temporary hardness. Yor the employment of this process on a large scale, various forms of apparatus have been invented, consisting of chambers, or tanks, in which the lime is mixed with water and from which the mixture passes into other large receptacles, wherein it meets the water to be treated. Thence, according to the nature of the apparatus, the water passes on to settling tanks or to mechanical filters, Avhere separation of the precipitate is completed. The largest plant of this kind in the world is located at Southampton, England, where 2,(X^0,000 g-allons of water are treated daily at what may well be reg-arded as an almost insignificant cost. The building in which it is installed covers less than a seventh of an acre, and is sufliciently large to accommodate additional apparatus whereby its working capacity may be increased by half. Whatever the forms of apjiaratus employed, the process must be carefully suj>ervised, 414 WATER. :ui(l tlie amount of liino added must ho constantly roo-ulatod ; for if too little is employeil, the lull extent of ]ios-^ihle soi'teninii- is not reached, while with too much, the \\:il('r is i\\:u\v alkaline and tlu' cai'honate of magnesium is retained. Caustic soda may be used for softenino- waters ecmtainino' carbon dioxide and the salts eausino- permanent hardness, Adtled in ])roj)er amount to combine with all of the free carbon dioxide, it forms car- bonate of sodium, which, in its turn, attacks and decomposes the other salts and causes their precipitation. Sodium carbonate itself may be added in the absence of free carbon dioxide to bi'ing- about the same result. In some processes for softening water, both lime and caustic soda or sodium carbonate are employed, the object being the reduction of both temporary and permanent hardness. Removal of Iron. Some ground-waters contain iron in such amounts as to be objection- able, both on account of its infltieuce on the system and because of its production of stains on linen and other textiles in the laundry. There are two principal methods of removing it, both of which depend upon the conversion of the ferrous compounds into the ferric form, with con- sequent separation as a precipitate. These are filtration and aeration. Filtration may be conducted through sand or coke or animal charcoal, and with either material the iron in solution is exposed to the action of air in the interstices and becomes oxidized to the sesquioxide, which is left on the filtering material. If the air supply is insufficient, and if there is mtich organic matter present in the ^vater, the sesquioxide may be reduced to the ferrous form and again pass into solution. When ground-water containing less than 3 parts of iron per 1,000,000 is ex- posed in large volumes to air, the iron will settle out almost completely within a day or a day and a half. Another method of removal by chemical treatment involves the use of ferric chloride and caustic lime in the proportion of 1 and 5 to 10 grams respectively to each 100 liters of water. By this, the " Kronke " method, all the iron can be removed, but it necessitates the use of a mixing tank, constant attention, and eventual filtration for the removal of the precipitated iron. Action of Water on Lead, and Other Metals. Action on Lead. — The question as to the best material for house- mains and distributing pipes is always an interesting one, and never more so than when a considerable number of persons in a community begin to show symptoms of lead-poisoning, and evidence is presented which incriminates the water supply. Aside from the matter of cost, the advantage of using lead pipes lies in the comparative ease with which lead is worked, since it may be bent to any necessary extent, and thus may be fitted to all manner of irregularities of construction withont the need of the frequent cutting, thread-making, and coupling, which the use of inflexible material involves. AiJTION OF WA'I'Eli ON LEAD AM) O'lllKIL METALS. ■\\ All (»r'(lliiju'y WMJcrs liiivc ;i ^icwlcr or Icsj^cr (ciKlciicy to atlju-k K-ad, iUic-onllii^' lo IIh' ii.'idirc and aiiionnl of lln- siib.'-laiK'c.'^ Ii<'l«l in .--oliitioM, 'V\\v i.-.i)\\\uun\\\ a(<'c|»(('il sl.ilciiKiit , llinl pure soil \valenelli,'- who found that the liiii'hest results in lead corrosion were obtained by the, use of ai-raled water charged with carbon dioxide. Invcstigiiting the plunii>o- soKent proi)erty of a ])ai-ticnlar water, A Liebrieh '' came to tlie same conclusion : that the simultaneous ])rcscnce of air and carbon dioxis has been conducted by Mr. H. A\'. C'lark,^ chemist of the State ]>oard of Health of Massachusetts, whose results indicate that oxygen is the more actively corrosive, and that either gas can act alone, lie employed distilled water, freed in the first phice as comjjletely as possible from these and all other gases, and then impregnated with known amounts of either or both. Clean bright lead pipe in equal amounts was placed in half-gallon bottles filled with water containing the gases in the jiroportions stated below, then sealed and set aside at a tenqKn-ature of (58° F. for one week, at the end of which time the amount of lead taken np was determined. The results are shown in the following table : No. Gases present. Amount of lead taken up (parts per 100,000). 1 2,4100 2 3 4 Carbon dioxide 4 inu-ts per 100,000 Ciu-bon dioxide 20 jiarts per 100,000 Oxygen y\, of saturation, CO.j 4 parts per 100,000 . 0.4993 0.8935 O.0S61 ' Journal fiir praktische Chemie, Series 2, 36, p. 317. - Gazetta ohimiea italiana, Jan. 21, lS9(i, p. 275. ■^ Zeitsoiu-if't fiir angewandte Chenne, 1S98, p. 703. * Annual Eeport lor 1S9S, p. 541. 416 WATEB. A specimen of load in a bottle containing water from which the oxviicn had been boiled ont as completely as possible, and the carbon dioxide removed by barinm hydrate, was kept at 8*2° F. for a week un- changed. At the end of the second week, slight action was discernible in spots on the surface, and analysis showed 0.0774 part per 100,000 of water. A specimen of ordinary distilled water in a bottle with a small air s[)ace in the upper part attacked a similar piece of lead pipe to such an extent that it yielded 10.58 parts per 100,000. In this case, the temperature at which the water was kept was 81° F. Inasmuch as all drinking-water contains more or less air in solution, oxygen is always present in some amount, and since, furthermore, car- bon dioxide is also generally present, it follows that, uidess substances with a decidedly deterrent influence are present, more or less corrosion is to be expected. Numerous instances of chronic lead-poisoning due to water rich in carbon dioxide are on record. At Sonmierfeld,^ for instance, where, in 1888, numerous cases occurred, it was found that the very pure water, rich in this gas, dissolved lead to the extent of about 6 milligrams per liter. At Lowell, Massachusetts, numerous cases were observed during the years 1898 and 1899, and it was dis- covered that one source of supply was rich in dissolved oxygen, and that the other, which caused by far the greater number of cases, was rich in carbon dioxide. Professor A. W. Hoffmann believes that a moderate amount of cai'- bon dioxide lessens corrosion by forming a protective coating of car- bonate, but that an excess of the gas dissolves it as bicarbonate. The gas is said also to have no action on lead coated with suboxide. Water containing free acid of any kind attacks lead. Sulphuric acid, which is supposed erroneously to form an absolutely insoluble compound, the sulphate of lead, is particularly active. In the ordinary chemical sense, sulphate of lead is insoluble in water ; but in the hy- gienic sense, it is sufficiently soluble to be capable of producing serious symptoms. This acid is not an uncommon constituent of water in minute amounts, especially in the vicinity of cities and large towns, where it exists in the atmosphere as an impurity due to the combustion of coal. The peat acids also have considerable action on lead, but they are not always present in waters from peaty deposits. Some very brown waters appear to exert but slight action, while others are intensely corrosive. The peat acids are due supposedly to the growth of certain micro-organisms found in peaty soils, for a neutral sterilized decoction of peat to which a small amount of fresh peat is added will in a short time develop an acid reaction and ability to dissolve lead. Liebrich ^ reports a peaty water poor in carbon dioxide and carbonates which took up 300 parts of lead per 100,000 over night, and more when calcium carbonate was added. The ammonium compounds and the nitrates have been supposed commonly to have a marked corrosive acition on lead. That this sup- ' Dcutsclie Yiorteljalirssc-lirift fiir (iffentliclie Gesundheitspflege, Suppl. XXIV. ' Zeitschrift fiir augewandte Clieniie, 1898, p. 703. ACTION OF WATFIi ON I. KM) AND OTIIEIi MIITM.S. 117 jxisitioii is ('(HTccI, liMS l)ccii |>r<)vc^ corrosive power. Sodinin an otiii:il Mi:r.\i.s. WW corrvtdcd very easily, cspcciiilK- iC llic w.-itcr cuiilairiH oxyj/cti, carhoii (li(».\i(le, a.iiiiindiia, or nil rates, ami lln' walcr i^ made inill<\' Itv (lie oxide aii\i' .'iriniMi<)nly liiai when one ciiim^cs suddenly f'loni the ii.-c of a Hr»ft water to anotlier (li;i(, is <|iiit(! iiiii'd, tiiei'e I'dIIou- ;i |( iii|i.,rary distnrh- aiK'CM)!' tJie ("mietioMs of llic di<;cstivc a|)|);ii;iliis. 'I lie iMf)st marked olTcHit is iisiialiy eoiislipatioii vvitli oeensional di;iiTlio;i. Loss of" ;i|»|k-- tit(; a,n'li(, iiansea are not. nneonnnon. Tlie eU'ects are dne to the infliienee ol' the salts (lansinj;' |)ernianeM( hardness, (hanj^e iVftrii hard to sol't, water is (jiiito as likely to cause iinaeeeiistoined lo(»seness of" the bowels from the withdrawal ol" this inflneiiee on the intestinal .scere- tions. Just how imieh of any one of thes(! salts may l»e s;Hd to he dis- tiiietly injurious to health is a matter of doubt, but commonly from 10 to 15 ])arts in 1()(),()00 of water are regarded as undesirable. Jt lias been asserted that tlu> use of hard water is one of" tlu," chief" causes of stone in the bladder, but such a connection is extremely improbable. How the use of ciirbouate and sulphate of calcium can brin^ about a deposit of uric acid, or of oxalate of calcium, or of |)liosphates in the bladder, can hardly be explained. The fact also that stone is very common in some districts where water is soft, and rare in some others where it is hard, suggests that the cause is to be looked for ratlier in the individual himself — his food, bis metabolism, his liabits of life, and, perhai)s, hereditary predis]iosition. Suspended mineral matter, as clay and marl, will often cause diar- rluea in persons not habituated to its ingestion, and not infrequently in those who are. The disease most commonly connected with mineral matters in water is goitre. That this disease may be produced by drinking-water, can hardly be doubted, for it is a well-known fact that in Switzerland and France, for instance, there are wells which yield waters which are used successfully for the intentional production of the disease, with the view to escape compulsory niilitary service. The enlargement is not neces- sarily a permanent disfigurement ; disuse of the Mater may be followed by disappearance of the swelling, but oftentimes the disease thus inten- tionally acquired persists. The exciting cause has been attributed to the presence or absence of certain mineral substances, but the wide variety of the sujiposeil agents is, of itself, strong evidence of the pom* foundation upon which the mineral matter theory rests. It is noticed, for instance, that in some districts where the disease is especially prevalent, the soil is largely magnesian limestone, and that, as might be supposed, the ground-water is rich in lime and magnesium salts. Therefore, it is reasoned, mag- nesian limestone must be the cause : but there are manv such districts 422 WATER. where goitre is unknown. j\Ioro than that, tlie disease is endemic in some quarters wliere the water is suit and ahnost free from lime and magnesium salts. Again, it lias been attributed to the presence of cer- tain salts of iron, but this theory also cannot bear the test, for these may be present where no goitre is seen, and may be absent where the disease prevails. Absence of iodine is another explanation based on nothing worthy of credence. The most probable cause is now believed by some to be an organism Avhich flourishes in the water. The tirst to promulgate this theory were Italian observers, who, in 1890, reported facts of interest bearing on the question, since wiiich time, other observers, particularly in India, have contributed farther evidence of its probable truth. The most striking facts have been presented by Surgeon-Lieutenant E. E. Walters,^ whose observations were pursued in a district in India 2,000 feet above sea-level, with extremely porous soil and a water sup- ply containing but slight amounts of organic and mineral matter, and but minute traces of iron. The inhabitants, who live under the same climatic conditions, but with diifereut occupations, may be divided into two classes : the native Bhutias and the Sepoy troops from the northwest provinces. The former are carriers and coolies ; they are omnivorous, but, by reason of poverty, mostly vegetarians. Their chief diseases are goitre, syphilis, and malaria. The temporary inhab- itants, the Sepoys, are all vegetarians, and are a healthy lot, practically free from syphilis, and living under excellent hygienic conditions. They had been in the district twenty months. Examination of 169 Bhutias showed that more than 75 per cent, had goitre ; nearly 70 per cent, of those over twelve years of age were afflicted. Of 380 Sepoys examined, 54 per cent, had goitre. The Bhutias say that their goitres increase during the rainy season, and this is borne out by the out-patient register and regimental admission book for 1895. All the British officers, too, had suffered from enlarged thyroids during the preceding rainy season. Their drinking-water was passed through a Pasteur filter; all other water used was taken as tea or soda. Taking up the several conditions which have been alleged as the cause of the process, he shows them to be not at fault in this particular district. Iron was present in the water in only minute quantities, and the highest degree of permanent hardness was but 3.5. As to lime as a cause, it appears that many of the Bhutias without goitres are great eaters of lime, while of the Sepoys, who never touch it, more than 50 per cent, developed goitres within twenty months after arrival. The theory that the disease is due to carrying heavy loads up and down hills, might satisfy in the case of the Bhutias, but not in that of the Sepoys, who, though not carriers, yet have goitre. Farther, as to age, it appears that 55 per cent, of the children under twelve had no goitres after living there all their lives, or about the same percentage as developed them among the Sepoys after a visit of only twenty months. He believes the disease to be due to an organism of the amoeba type, with a selective power against the ^ British Medical Journal, September 11, 1897. WATEli AND I US HASH. 423 tliyi'oid or its Hocrcl-ioii. I'\)i' ;i linic llir -y-l<'iri ()|i|)OS(!H it, utirl Homc- iiliutH ,sii(', (<» >;\\ , ;iildi(ion;d rcKistitifr power is conCerred by (liyi'oid tiil)l(»ids, wliicli kcc]) the poi-on in <-licck juid niiow (lic^liind (o recrovcr i(s normal si/e ; hnf on u ididraw in^ tlio accessory a'4(ii(, (here; is dinunished i'esis(ane(; and (lien aj^ain an increase in si/c. Disorders Connected with Organic Pollution. — Ordinary ve^e- tabh; niaitcr in suspension and al)nndan( erow i lis o(" al^a; and oilier water plants sometimes (unise diarriio'al (i'onl)lcs, hut tlicy d') not eau.«e Hpeeilie disease. Pc^aty matters in solution ha\'e now and then aj)peare(l to be connected wi(h in(es(inal deraiitrcnieiit, hut we have no al)Sf)lute knowledge that they actually lia\'e heen or can he a caux; of such trouble. We know three; epidemic diseases w liieli \\q may say witli certainty can he earried by water. These are : cholera, typhoid fever, and dysentery, hut it is said commonly that water is a great factor in the spread of di})litheria, yellow fever, and malaria. In the case of dij)h- theria, the weiidit of evidenee is certainly against its being a water-horne disease. There is some evidenee of its spread through the use of a common water supply, hut in these cases there is usually a common drinking vessel, and probably a preexisting case of the disease among the drinkers. The diphtheria organism cannot long survive in water which is jiot very extensively polluted. As to yellow fever, there is no evidence whatever of value, but in the older literature of hygiene many outbreaks attributed to polluted water are recorded. In the light of our present knowledge, these instanees have, naturally, no staTuling, but in justiee to those Avho recorded them it must be said that, before the discovery that the disease was mosquito-borne, the evidence presented seemed to be uncontro- vertible. For example, outbreaks occurring at sea aboard ships that recently had been in infected ports, where the water-casks had been reii lied, could not be attributed to telluric influences, and the rejtlenished water-supply offered the only explanation. As with yellow fever, so with malaria, abundant evidence of con- nection with water as a cause has been recorded, although the fact has long been known that water from malarial districts may be used by communities at a distance witliout harm, as is the case with the city of Rome. One of the best cases which have been accepted as proof of trans- mission by water is that reported by Laveran, who failed, however, to furnish certain facts which (nir present knowledge Mould require. A detachment of soldiers drank at a certain well, and then enjoyed a hearty meal ; another detachment ate flrst, and later drank from the same well. Of the former, all beairae sick with malaria ; of the latter, 424 WATER. not one was affected. The ditferenoe in the results was thouo;lit to be due to the fact that those who escaped took no water until the o;astric juice was secreted in the process of dioestiou. C^uite a number of cases are recorded in which men on shipboard have used the water of certain casks which others had declined, the former becoming sick with malaria, and the latter escaping. There is evidence that certain animal diseases may be spread by water containing the specific organism. Hog cholera and anthrax have certainly been spread by water into which the bodies of those that had died of these diseases had been thrown, and glanders may be spread from horse to horse by the use of a common drinking trough. The diseases of greatest interest in connection with drinking-water are two which we know can be spread by infected water — cholera and typhoid fever. The first-mentioned happens, with us, to be one of minor interest, inasmuch as it is a most uncommon visitor ; the other, however, is always with us, and we have, therefore, constant oppor- tunity for observation of the influence of polluted water in its causa- tion. The strongest proof of the value and efficiency of the purification of water by filtration through sand is the drop which occurs in the mor- tality from typhoid fever when a community abandons the use of un- treated polluted water, and adopts this method of improving the quality without changing the source of supply. The city of Lawrence, Mass- achusetts, for example, prior to and including part of the year 1893, used the unfiltered water of the Merrimac E,iver, into which is poured the sewage of a succession of large cities and towns having an aggre- gate population of several hundred thousands. In the year mentioned, the process of filtration was adopted, and good results were almost immediately evident. Following are the death-rates from typhoid fever per 10,000 of population for the four years immediately preceding and for the same period following the change : Preceding change. Year of change. Following change 1894 . . .4.7 1895 . . .3.1 1896 ... 1.9 1897 ... 1.6 It is but fair to add that about half the deaths from the disease in 1894 and 1895 were of persons who persisted in drinking unfiltered water directly from the canals. The city of Hamburg adopted filtration in May, 1893, after a most devastating epidemic of cholera in the preceding year. Typhoid fever had always claimed a very large number of victims annually, and dur- ing the four years 1890-1893, the death-rate from the disease was 2.6 per 10,000 ; but in the next two (1894-1895), it fell to 0.75. 1889 . . 12.7 1890 . . 13.4 1891 . . 11.9 1892 . . 10.5 WAT/':/: AN/> /)IS/':asI':. 426 'V\\o. cxpcricMcf" of" I 'liil;i(l<'l|)lii;i. williiii (vf.ciif, year-! fiiriiiHliCH a nio.st iiisi.riic,(,iv(; (rxiiiiiplc ol tlu; (laiiLr<'i' ol iisiiit^ polliilcd w;it;<;r. ])iiririg tli(! first six rnoiillis of" fJi(! yiVAV 1H!)I), in ;i |)01, in a jiopMlalion of .ahoiit 1,300,000, tli(!r(! o(;cMi'r(!d nearly 2500 (;as(;s ; and of" tliesr-, no fi-wer than 38!) won! n^ported in a single w<;(!k, tins niirnhctr beinj^ tlie lar^a^st ever roporfod in any W(!ek in tlio iiisfory of IIk; eify. In that [»art of the city to wlii(!li the new sn[)j)ly of filtered vvalor w.'is f"nrnished, tluTe was an almost immediate fall in tlu; typhoid rale, the immediate nrnj^h- borhood not so snppiied eonfimiin of ordinary sewa<;<' containing the essential organism, or of feces or mine discharu;ed alon^ tht; hanks of" a river or lake, for example, by persons sulTei-iiiL!; with or convalescent from the disea.«e. Indirect infection occui's from discharfi;cs deposited in or upon the soil, and thence washed by rain into bodies of water or down w a id intowell.s. Ordinary sewa<>;e ])ollution is not sufiieient to brinjr about an outbreak of the disease, nor will sjiecific ])ollution necessarily always be f"olh>weVV('ll . . l*';ill Ivivcr Spriiii^licld '^riiiiiiioii . , N(>rlli!iiiii)l,on IjyiMi . . . . New I'ciK'nnl Ncwtoii . . Mal(lci) . . . l<^itc'lilnirjj; . Woliiini . . . Soriici'villc Clii'lsca . . . WiilUiiun . . Yonrly niiiiilmr of'(l>(:r fXjatliN In r>ntiu<\ \>i-rUA (Jiictionof ty|iliol(l fcv(;r |M;r Imtnlri'd wiiU-r NUpply. \h:t IO,(HKi IH7m of lli'/«<- in to \m). ftrnl. 1873 1H75 IH72 1.S74 isyr, is7(; 1.S7I I.S71 1 si;'.) IS70 1.S70 1H7'2 1 H7.", lKfi7 1807 1873 8.93 8.33 7.(53 0.32 .'i.2!> r..r)2 4.04 :i.87 ."..KO '.',M 3. If) 2.9r, 2.95 2.89 2.42 133 1(K) 124 81 65 82 37 43 49 56 44 30 3»} «9 48 30 It will be noiiccd ||i;i( oC (licsc sixlccii cities llicrc were three whieli showed no iniproveineiit, and two of these wore worse (iff than before. The reason for tliis is clear. All three arc niannfacturing cities, sitnated on rivers ])olhiled by sowau;e. At Holyoke, while the public supply is but .slightly liable to eontaniination, the operatives in the fac- tories used water from two other sources, subject to gross pollution ; namely, from the canals, the entrance of one of which is sitnated close to the outlet of one of the main sewers of the city, and from wells indirectly supplied by the canals. Comparison of the death-rates from typhoid fever among those of different occupations, brought out the fact that the operatives in the mills which used canal water suffered from the disease three times as much ]iro rata as all other jiersons. Lowell and Lawrence, at the time mentioned, were using the pollutwl water of the Merrimac River. Lowell took its supply fourteen miles below the point of entrance of the sewage of Nashua, N. H., and con- sumed it without treatment. Ijawrenee drew upon the same supply, after its enrichment by the sewage of Lowell, at a point but nine miles below the outfall of the latter's sewage. In ISUl, Lowell sutiered unusually from typhoid fever by reason of the additional contamina- tion by feces of typhoid patients discharged into Stony Brook, a small tributary of the jNlerrimac, only three miles above the intake of the water-works. The conditions of all three ])laces have since been changed. At Holyoke, warnings were posted for the benefit of the operatives ; Lowell abandoned the river in favor of ground-water in LS9o, and in the same year Lawrence instituted filtration. In all of the three cities the expected happened ; namely, a marked diminution in the death-rate. Examination of the above table reveals the fact that in the majority of the sixteen cities the reduction in the typhoid death-rate was most pronounced. In some of them, the diminution has proceedini to a much greater extent than is shown here. In 180G, three cities with aa 428 WATER. aggregate population of 70,000 showed less than 1 death per 10,000 from this disease, and in one of them, Wi»burn, there was none at all. That the favorable effects produced hv iiltration of water sup])lies have not been confined to tlie decreased incidence of tv])li<)id fever is shown by the following fact: In 1893 it was noticed, independently, by Hiram F. Mills, C. E., of the State Board of Health of Massa- chusetts, and- Dr. J. J. Reincke, of Hamburg, Germany, that not only was there a marked decrease in the incidence of tyi>hoid fever subse- quent to the installation of filtration ])lants, but that the general death- rate also suffered an equal or larger decrease. As a factor in this de- crease in the general death-rate the mortality of children under one year of age undoubtedly plays a considerable ])art, as will be seen by the following table, taken from one of Dr. Reincke's annual reports and referred to by Sedgwick and MacNutt.^ The following table shows the deaths of infants under one year of age in Hamburg from gastro-intestinal diseases : Preceding change. Year of change. Following change. 1884. . . 1143 1889 . . . 1557 1893. . 857 1894 . . 708 1885 . . . 1159 1890 . . . 1198 1895 . . 918 1886 . . . 1601 1891 . . . 1500 1896 . . 767 1887 . . . 1758 1892 . . . 2541 1888 . . . 1063 In 1904 this decrease in the general mortality, due to the purifica- tion of public water supplies, was defined numerically by Hazen in the following statement, which has come to be known as Hazen's Theorem : " When one death from typhoid fever has been avoided by the use of better water, a certain number of deaths, probably two or three, from other causes have been avoided." Sedgwick and MacNutt, as a result of further investigation of this subject, came to the conclusion that Hazen's estimate of the decrease in the general mortality has been, if anything, too conservative. In fact, the improvements noted at Lawrence, Mass., and Lowell, Mass., seemed to indicate that in the former city 4.4 deaths and in the latter city 6 deaths were avoided from causes other than typhoid fever, where 1 death from typhoid fever had been avoided by the substitution of a pure for a polluted water supply. The following tables, taken from the article by Sedgwick and MacNutt, show graphically the effect of this substitution, both upon the typhoid fever death-rate and upon the total death-rate, minus the typhoid component, for the cities of Lawrence and Lowell, Mass. It will be noted that the unused portions of the scale below each curve have been cut off, so that no base lines are shown : ^ On the Mills-Reincke Phenomenon and Hazen's Theorem concernins; the decrease in mortality from diseases othei' than tyjihoid fever, following the purification of public water supplies. Journal of Infectious iJi.seases, Aug., 1910. WA'I'h'n DISK ASK. Vut. .",7. DEATH RATES-LAWRENCE, MASS. 420 cc •* in «D ^ ^yt '.t -r Fio. :-;s. DEATH RATES-LOWELL, MASS. 1 \m 1 TYPHOID FEVER \ / 100 \ / X -AU-« I ^ J~^ <— < k:=|— 3 1-^ ~\ T^"^ f *»-4— 60 1 — — i" -H J 1 1 V i,^,^, , ..... .1. i ^t ' 1 " - - 1- 1 —i. r'^^=^-—-*=' — <~ — ^> 2G0O 1 / ^ ■ 1 1 1 1 ) k 1 / N TOTAL DEATH RATE MINUS TYPHOID COMPONENT 2-100 1 / V.^ >. / ( , 1 / ^ "-( y-— < \ 2200^ / \ ^. 7 t ) ^ r — '^ K, / L 2000 1^ y \ ^, / N li r t 9 1 ^^^^ 'Si <, >' laK) 1 1 ^^^ co"*»o<:Di— ooa5Q"-ioico-*iocoi.— ooo»0'HC«cO'»»< >a Examples of Typhoid Fever Epidemics and of Limited Out- breaks Traced to Infected Water. — For the purpose of illustrating to what an extent speoiHcally polluted water can, under favorable con- ditions, bring about a sudden outbreak or explosion, the following cases have been selected from the many which are to be found in the literature of hygiene. Epidemic at Lausen, Switzerland. — This best known and most often qnoted of epidemics of typhoid fever was practically the first one of any considerable extent to be traced undisputably to the use of sj>e- cifically polluted Mater, although many outbreaks, large and small, had been ascribed to the use of water " containing considerable organic matter," and only supposedly infected. Up to 1872, this village of 780 inhabitants had not been visited by typhoid fever, even in sporadic cases, for sixty years. On August 7th, with no previous warning, ten persons Mere seized, and during the next ten davs nearlv sixtv more. The number of cases increased 430 WATER. from day to day until 130 persons, or one-sixth of the entire popula- tion, had been seized. So largo a percentage of involvement pointed to some common cause, and the iinnnniitv enjoyed by the inmates of a group of houses not connected with the public water supply directed attention to the latter, wliicli was derived from a spring at the foot of a ridge about 300 feet high, between the village and the Fiihrler valley. In this valley, at a ])oint between one and two miles distant from Lausen, was an isolated farm where dwelt a man who, on June 10th, s]u)rtly after his return from a visit, was taken sick with typhoid fever. Before the end of July, three cases more devel- oped in the same house. The discharges of all four were thrown into a brook in which the family washing was done, and which served to irrigate the meadows hclow. AVhenever it was dammed up for this purpose, the volume of the water su})ply l)eyond the ridge was noticeably increased. Between July 15th and the end of the month, the meadows had been submerged by this process, and in three weeks from the beginning of the operation, the explosion occurred in Lausen. The sequence of events was, then, the appearance of the initial case on June 10th, and of three more in the same house before the end of July, the daily pollution of the ^v'ater of the brook, the damming of the brook in the middle of July, and the appearance of the first cases in Lausen on August 7th. Everything pointed to direct connection between the impounded water and the spring a mile or more distant on the other side of the ridge, and its existence was established by dumping about a ton of salt into the brook and noting its speedy appearance in the Lausen spring. As a very large amount of flour, deposited at the same place, gave no evidence of its appearance, even in traces, it was proved that the water passed through a coarse filter- ing medium rather than through an open underground passage. The Plymouth, Pa., Epidemic. — The town of Plymouth, Pennsylvania, had, at the time of the epidemic in 1885, a population of about 8,000 people. The general water supply w^as derived from a mountain brook, which was dammed at intervals so as to form a series of im- pounding reservoirs, but a large part of the population was supplied by individual wells. A citizen who spent the Christmas holidays at Philadelphia returned in January to his home, ill with typhoid fever, and had a very protracted sickness. During the entire period, his excreta, which were in no way disinfected, were thrown upon the snow and ice on a slope not forty feet away from the brook, at a point mid- way between two of the dams. At this time the brook Avas frozen over, and it remained so until the approach of spring. During the la.st third of the month of March, there was a sudden period of warmth, and the snow and ice began to melt. Shortly afterward, the warm spring rains began, and the ice and snow and frozen excreta upon the slope were melted, and the entire accumulation was washed into the brook, and thence into the water mains. AV-ithin three weeks there- after, cases of tyjihoid fever by tlie score made their appearance throughout the town. On some days, more than a hundred new cases were reported, and on one, tiie number reached nearly two WATKIl AND D/Sh'ASh: 431 liiiM(h'('(l. 'IMk! lol.il iiiiMihcr <>(' -ciziircH lius viirioiihly Ik-cii t-lal('()(). 'I"|ic iiiltilhfr of (Iciillis \v;is tiol, lc,-s lli.'iii III, ;iMil ii.i- liccri |tl;icx'(| ,'is lii;^li as 1 'jO. I (. WiiH riic.ti('!illy fo IIiohc wh(>H(( lioiiscH wci'c sii|i|>li((l liy llic lown ni.-iins, aiiipliasizf(l in nnc sin'cf, wln'ir IIh' Iioiiscm f»ii otic -idf all had OIK! or more cases, while iho-e mi I he nihcr Ii;id Done at alL 'riic. lormci' were supplied l)\ (lie lowii iii;iiii.-, ;iiid fhc lafter depr-iifh-d upon wells. Outbreak at Uvernet. — A sotiie\\li;il siniilar onlhi'eak, on a iiiueli snialhiT scale, is repoffeil hy I )r. l)iipairivy, and his exc^'eta were thrown u])on the ground in a neighboring field. His soiled clothes were washed in the sj)ring nearby. At the time of the soldiers' arrival, a mniiber of heavy rains occurred, by wdiich the surface impurities of the soil in the neighbor- hood of the house where the child lived would, by reason of the incli- nation of the ground, be washed toward the house occupied i)y the soldiers. This was supplied by water from a small stream through a rude main constructed of worm-eaten hollow logs laid in a shallow depression in the surface of the soil. There could be no question of the probability of contamination of this supply by the ftccal discharges thrown upon the ground iu the vicinity, and in the absence of any other cases and with the high percentage of seizures in the one house, no other explanation appears to be possible. Epidemic at Ashland, Wisconsin, in 1893-94. — This outbreak is one of })eculiar interest, iu that, iu addition to serving as an excellent illus- tration of the danger of using the same body of water as a place for the disposal of sewage and as a source of drinking-w^ater, it Avas made the basis of an action at laAV, Avhich established the liability of AAater companies and nuuiicipalities in case of sickness and death caused bv the distribution and use of infected water. The city's supply is derived from an arm of Lake Snj>erior, Che- quamegon Bay, upon which the city is situated. This bay, which is about t\\el\e miles long, and of an average width of live, varies from eight to thirty-six feet in dejith. Xorth of the city, and extending outward in a northwestwardly tlire^'tion, is a lireakwater consrructetl 1 Lyon medical, Jan. 1, 1890, p. 5. 432 WATER. for the protection of the hnrhor ao:ainst nortlierly p^les ; ami between it and the city the mouth of the water intake is located about a mile from the shore. (See Fig. 39.) The sewage of the city is discharged farther to the west and south. The currents in the bay follow the course indicated by the arrows in the tigure, and carry the sewage toward the breakwater and over the mouth of the intake. Tliis con- dition of aliairs was brought to the attention of the company by the health boards of the city and state repeatedly, but without results. That the water \vas polluted, was evident on mere ocular inspection, for it was often cloudy or markedly turbulent. During the Avinter of 1893—94, typlu)id fever made its apjiearance in the city, and from the initial crises a disastrous c])idemic developed, w^hich led to the establish- ment of a model filtering-plant. The action at law referred to above, w^as brouglit by the Avidow of one of the victims. In evidence, it was shown that he lived continu- ously in Ashland, and drank no water other than that supplied by the Fig. 39. Conditions obtaining at Ashland, Wis., prior to the epidemic of 1893-94. water company ; that previous to his seizure the disease had prevailed in the city, and that the discharges from the antecedent cases had passed into the waters of the bay by way of the city sewers. The court found for the ])laintiff in the sum of |5,000. Epidemic at Luneburg in 1895. — The ancient town of Liineburg, with a population of 22,000, has a system of sewers which empty at two WA'I'KIl AN/} DISK ASK. 4.*}3 poiiiis iiiio llic hiiimII Iv-ivcr- I liiiciiaii. Tlic piiMir- \v:il:il ones .'■iipply tlic haiiic jKii'ts of Ui(! lown, il happens (lial (heir mains run llirou^li the Hariic Htrcots, and thai- nol alone adjoininij; lioii.-es, Iml even din'crciit Ht^jfiw* of {\\{\ HaiMc hniMine; arc snp[»lied hy either one aeeordin^ to fMrnirn- stiiiK'dS. 'i'he IJalhs ( 'Oinpany fnrnislies a ^n-ouiid-\vater wiiieji is |»er- ((•(•iJy ^ood, except lor ils rather liiLdi eonteiit of iron, which soinetiiiicH has (!iUiS(!d more or less tronhlc. The oilier lai'L'^c corporation, known as the Abis ( !omi)aiiy, obtains its water IVom the nincnun, iisnally at a point above tlic town ; bnt between -Inly loth and "JOtli, it drew it from a place in the middle of the town, opposit*- the |)umpinc'-si;ition, wlien* th(^ water was exIreiiieU' inipnre. l*re\ions to ihe-e dat<'S, ty|)boi, or 03, the dam at Boydstown, some seven or eight miles above Butler, was carried away, and the main source of supply being thus lost, the water company was obliged to use water from the Thorn Run reservoir and to pumj) directly from the creek at the pumping-station. Before distribution, the water was treated in a rapid mechanical filter, from which it was sent to the city reservoir. On October 21, the filter plant was shut down for repairs, and during the next ten days the city was supplied with un- filtered water, taken directly from the creek at the pumping-station. On November 2, an epidemic of typhoid fever began, and so rapidly did it spread that, by December 1 7, no less than 8 per (ient. of the popu- lation (1270 cases) had been attacked, and 56 persons had died. That the epidemic was due to the water-supply was emphasized by the fact that a portion of the city, known as Springdale, with a population of about 2500, not provided with city water, but supplied by deep wells, was almost wholly exempt, there being but 2 cases within the district. The source of the infection was not far to seek. Throughout the sum- mer and autumn, fairly numerous cases of typhoid fever had occurred at various points on the watershed, and there was amj)le opportunity for the dejecta to be carried into the numerous small tributaries and thence into the creek. In one house, for example, provided with a privy overhanging a small stream which empties into the creek within a short distance from the pumping-station, there occurred, subsequent to October 1, no fewer than 5 cases of the disease. In another house near Thorn Run dam there was a case about the middle of August, and this was followed by 3 others. Epidemic at Ithaca, N. Y.,in 1903. — At the time of this outbreak, Ithaca, New York, the seat of Cornell University, was a city of about 13,000 people, with an additional student population of nearly 3000. Its location and surroundings are, in general, unusually favorable to health ; in 1900, the death-rate from all causes was but 16.3 per thousand. The public water-supply was furnished by three creeks, which flow into Lake Cayuga, but many of the population depended upon private wells, of which there are about 1500 within the corporate limits. The water company which supplied the city proper derived its water from Six-mile Creek and Buttermilk Creek ; the University was supplied by Fall Creek, under its own management. The watersheds of these three 1 Wiener klinische Wocbenschrift, July 7, 1898. WATI'Hi AND n/Sh'ASl':. '4.'}5 creeks an; nol, liu'trc ;iihI (Ixy iirc more or Ic-s fjiiickly popiilutcd, Ahuridiirit ((pporLimilics cxisl for <]ii('(;l, iiili-ction of :ill tlin-r; crcJfkH, privicH ;iris(! alonjj; i'':ill ('reek were (iveri worse, altimuj;!!, as will be seen, this source of supply appears not to have be<'n specifically pol- luted. In addition to the usual sources ol" contanduation of the wnie.T of 8ix-itdlc Creek, (here were employed during November and j)art of J)e(U'ml)cr, 11)02, about (JO laborers in tlu; (!oiistruetion of a dam, but candul iiKpiiry failed to show (he existenc(! of any sickness among them during the period of their employnKsnl. The j)ul)lic supply had long been vit^wed with susjucicm, and many of the popukition wlio used it were accustomed to boil the water before drinking it. l)iarrh(eal disturl)anceK and a nnld form of tyj)hoid fever, known as " Ithaca lever," had for many years })een very eonunon. During January and February, 11)02, it is said tliat tliere were nearly 100 cases of ty])hoid fever in the city. During the spring of that year, repeated bacteriological and chemical analyses of the water of Six-ndle Creek, taken from the servi(;e ])ipes, yielded results which indicated dangerous pollution, and the ])eople were warned through the newspajiers against its use without previous boiling. On January 1, 11)03, several cases of undoubted typhoid fever were reported, and thereafter the number reported daily increased to such an extent that, on February 2, there were no fewer than 237 cases under treatment. 15y the middle of March nearly 800 eases had been reported, l)ut the actual number of persons alFected was undoubtedly much larger. It is asserted that more than 1000 cases existed at that time, and that during the first six months of the year there were more than 1300. Investigation showed that those infected were users of the water supplied by the water eomjiany, and that practically no cases occurred among those who drank well-water from Fall Creek. Although the University was supplied by the latter, a large proportion of the student body lived in boarding-houses supplied by the comj)any, and among these the cjiideraic found many victims. Accounts as to the number of students seized ai'e very variable, for a large proportion left t(' towns ;iii,()()0 p(;rson.s indni^^c in hemp and hashe<'sh io a sho. kin^^ dcLiree. |''((r wcck.s Ixifon; tluj aw I'cstiv^a! in Jinie and -Inly, |)ilt;rims eome Iroopin^r in l»y thoiisanrlH every day. Thev are led by the temple cooks to the nntnlx-r of !)(),()()(). ()\'er 100, ()()() men and women, many of I hem nnacciistonicd to work or c\posnr(>, \\\\:i:^ and strain al the r-.w nntil they droj) ex- hanstcd and hh»ek Ihe road with their hodie-. I )nrinf:; every month of the vear a stream of devotees Hows ah)n<:; the; L:;i"eat ( )rissa n»ad from Cah-nlta, and every vi!IaL;;(; for three Imndred miles has its pilgrim oncainpmenls. "The ])eople travel in small bunds, which at tlie time of the ^reat feasts actually touch each other. Five-sixths of the whole are females, and 1)5 ])er cent, travel on foot, many of them marchinti' hiindn-ds and even thousands of miles, a contingent having been drmnmed up from everv town or village in India by one or other of the three thousand (Muissaries of the temple, who scour the country in all directions in search of dupes. When those pilgrims who have not died on the road arrive at their journty's end, emaciated, with feet bound u]i in nigs and plastered with mud and dirt, they rush into the sacred tanks or the sea, and emerge to dress in clean garments. Disease and death make havoc with them during their stay ; corpses are buried in holes scooj^ed in the sand, and the hillocks are covered with bones and skulls washed from their shallow graves by the tro]>ical rains. " The temple kitchen has the monopoly of cooking for the multitude, and provides food which, if fresh, is not unwholesome. Unhappily, it is invsented before Juggernaut, so becoming too sacred for the minutest portion to be thrown away. Under the influence of the heat it soon undergoes putrefactive fermentation, and in forty-eight hours much of it is a loathsome mass unfit for human food. Yet it forms the chief sustenance of the pilgrims, and is the sole nourishment of thousands of beggars. Some one eats it to the very last grain. Injurious to the robust, it is deadly to the weak and wayworn, at least halt' of whom reach the place suffering under some form of bowel complaint. Badly as they are fed, the poor wretches are worse lodged. " Those who have the temporary shelter of four walls are housed in hovels built upon mud platforms about four feet high, in the center of each of which is the hole which receives the ordure of the household, 440 WATER. and arouiKl whieli tlio inmates cat ami sleep. Tlie ]>latforms are covered with small cells without any windows or other a})ertures for ventilation, and in these caves the pilgrims are packed, in a country where, during seven months out of twelve, the thermometer marks from 85° to 100° F. Hunter says that the scenes of agony and suflbcation enacted in these hideous dens baffle description. In some of the best of them, thirteen feet long by ten feet broad and six and one-half high, as many as eighty persons pass the night. It is not, then, surprising to learn that the stench is overpowering and the heat like that of an oven. Of 300,000 wlio visit Juggernaut in one season, 90,000 are oi'Um packed together for a week in 5,000 of these lodgings. In certain seasons, however, the devotees can and do sleep in the open air, camping out in regiments and battalions, covered only by the same meagre cotton garments that clothe them by day. "The heavy dcAvs are unhealthy enough ; but the great festival falls at the beginning of the rains, when the w^ater tumbles in solid sheets. Then lanes and alleys are converted into torrents or stinking canals, and the pilgrims are driven into the vile tenements. Cholera invariably breaks out. Living and dead are huddled together. In the numei-ous so-called corpse-fields around the town as many as forty or fifty bodies are seen at a time, and vultures sit and dogs lounge lazily about gorged with human flesh. In fact, there is no end to the recurrence of inci- dents of misery and humiliation, the horrors of which, says the Bishop of Calcutta, are unutterable, but which are eclii)sed by those of the return journey. Plundered by priests, fleeced by landlords, the sur- viving victims reel homeward, staggering under their burdens of putrid food wrapped up in dirty clothes, or packed in heavy baskets or earth- enware jars. Every stream is flooded, and the travellers have often to sit for days in the rain on the bank of a river before a boat will venture to cross. "At all these points the corpses lie thickly strewai around (an Eng- lish traveller counted forty close to one ferry), which accounts for the prevalence of cholera on the banks of brooks, streams, and rivers. Some poor creatures drop and die by the way ; others crowd into the villages and halting-places on the road, where those who gain admit- tance cram the lodging-])laces to over-flowing, and thousands pass the night in the streets, and find no cover from the drenching storms. Groups are huddled under the trees ; long lines are stretched among the carts and bullocks on the roadside, their hair saturated with the mud on w^hich they lie ; hundreds sit on the wet grass, not daring to lie down, and rocking themselves to a monotonous chant through the long hours of the dreary night. " It is impossible to compute the slaughter of this one pilgrimage. Bishop Wilson estimates it at not less than 50,000. And this descrip- tion might be used for all the great Indian pilgrimages, of which there are probably a dozen annually, to say nothing of the Inmdreds of smaller shrines scattered through the peninsula, each of which at- tracts its minor hordes of credulous votaries. So that cholera has PAIIASI'I'KS ANh DIUSKINd-WATEH. 411 al)lin(liiii(, ()|»|)(»i( iiiiilics (or ,s|)r<';i(liii^'- over tlu; \vIh»I<' oC I f Ii)(|<.-t;iii iwvxy yviiv \)y iri;uiy lin^jc ;iniii<'s o(* lillliy |til^rirMH ; and llw coiint.ry \tHv\\' well us nnnd»ers ol" ejr^s inllie small intestine, and these are expcHed in the f:eces. \\'h<'tlicr IIk; freshly diseharii;ed ess;uy. Whcirever this parasite is known to |»re\;nl extensively, the people nso pollnted water for drinkino^. Pin worms, or scat worms, Oxyuris vermicularis, are spread |)rol»al)]y by water. They locate in the ciccum and npper colon, where the female de})osits ejijgs in large numbers, which, reaching a water-supply after being discharged through th(^ bowel, may be taken into tlie stomach, where the enveloj)e of the embryo is disintegrated by the gastric juice. The larv;e develop in the small intestine and come to maturity in about four w'eeks. Guinea worms, Dracunculus medinensis, are said to invade the body through the skin during bathing or through the stomac^h in drinking- water ; the evidence of the latter method is detinite. In the stomach, the embryos are developed rapidly, aud soon the impregnated female proceeds from the alimentary canal to the subcutaneous tissues in various parts of the body, where she finally breaks through the skin and esca]x>s. The living embryos which are then liberated, finding their \vay into fresh water, enter the bodies of the comn^ou fresh-water flea, Cijclops quadrieoniis, which acts as the intermediate host and conveys the organism to the human stomach. In a case reported by Dr. John Patterson,^ the pati(mthad an abscess on the upper part of the left tibia, from wdiieh, when it was excised, a pi^rtiou (4 inches) of a worm was removed. I-iater, he had an abscess aud sinus of the left calf, followed by a swelling back of the inner malleolus, aud in this a portion of a worm, 25 inches iu length and devoid of a head, was found. Dr. Edward Francis - had under observation for six weeks at the U. S. Immigrant Hospital (N. Y.), a native of the Gold Coast, who arrived iu June, 1901, with a history of having been troubled with these para- sites during the preceding three months. During his stay at the hos- pital five woru:is appeared : one on the front of the right ankle, one on the dorsum of the right foot, one on the front of the left ankle, one ^ Medical Eecord, October 7, 1899. '^ American ^ledicine. October 26, 1901. 442 WA TER. below the left external malleolus, and one on the dorsum of the left foot, near the toes. Que Nvorni presented 26 inches in one piece ; the others measured 10 to 18 iuches, but were removed in pieces. AVhip worms, Trichocephalus dispar, which are said to be extremely common in Paris and some other places outside the tropics, are spread wholly by water, without which the embryo cannot develop within the egg. Taken into the stomach, the envelope is dissolved and the liber- ated larva attaches itself to the wall of the intestine, A\here it proceeds very slowly to develop. It does not reach full maturity until about a year has elapsed. Filaria sanguinis hominis, the parasite which produces chyluria, ha-ma- tochyluria, and elephantiasis, is believed to find its way into the system through water contaminated by mosquitoes which have sucked the blood of persons suifering from the parasite. The adult female ]>roduces an enormous nuuiber of minute embryos, which pass into the blood ; and when these are taken into the stomach of the mosquito, they wander to other parts of the insect, where they become farther developed, and later may be transferred to water, through which they are believed to pass into the human stomach, where the cycle is completed. This para- site is not confined wholly to the tropics, and occasionally is seen in our Southern States. (See Chapter XII.) Bilharzia hasmatobia, the cause of a peculiar heematuria common in parts of Africa, is believed by many to be transmitted by drinking- water contaminated by the urine of persons suffering with the disease. The embryos probably enter the system of some other organisms, which play the part of intermediate hosts and advance their development one stage. Ankylostomum duodenale (XJncinaria duodenalis), the cause of the anaemia formerly supposed to be peculiar to miners and others engaged in underground operations, was until recently believed to be disseminated chiefly by polluted water ; but, as has been said in the consideration of the relation of soil to disease, this idea is no longer tenable, the chief, if not the only, source of infection being soil polluted by the intestinal discharges of those already infected with the parasite. Strongyloides intestinalis, the parasite of an endemic diarrhoea of Cochin China, first described by French investigators who discovered its rhabditiform embryos in the stools of soldiers returning from China in 1876, was found by Perroncito to occur in association with Ankylos- tomum duodenale in the discharges of laborers afflicted with " St. Gothard tunnel anaemia", has been reported in various countries of Europe, in Egypt, Brazil, the Indies, and Pliilippine Islands, and within recent years in various parts of the United States. According to Dr. M. L. Price ^, the occurrence of eggs in the stools is very rarely observed, unless there coexists an uncinarial infection, and the parasite is probably introduced by way of the mouth as the filariform embryo, though infection of animals has been produced by means of the eggs. He believes that the vehicle by which the parasite gains access to the ^ Journal of the American Medical Association, September 12 and 19, 1903. WE. 1 l.'^> systom is fr(;(|Uoiiily \\u' drinkiiit^ wafer, hiit lli;it, fnsli v"<.'Pt'il»l(H from IjukI in:uiiir<'(l willi liiiirKiii upon it and h(>(!omes wet cither hy rain or hy water from helow, and then freezes and he<^om(>s part of the ice, it will contain all the im|)nrities whieh have hccn washed out of the air. Tf, whih; tin; ice is ihin, holes are cut so as to permit flooding from helow, it will contain all the impurities of the water. Cut from shallow ponds, it will he pure or imj)ure acc<»rd- ing to the (luality of the watci- and the depth to whieh it freezes. Water from such ponds, if ])ollute(l hy surface washings or sewage matters, is likely to yield ice which, wlieu melted, will give off olfeusive odor.s. It is a common belief that bacteria are killed in ice, but many varieties will retain tli(>ir vitality in it for a very long time. As early as 1871, Burdou Sanderson showed that even the purest ice is likely to contain them in some degree. Chantemesse and Widal ])rove A LI'.IIM I NOI I) AMMONIA. \ \'i paper to Hctciint ;i, li^lilcr fil., ;iii|toscdlv (^Ic.'in at t lie sl:i rl , should he rin-cd thoroughly with lh(( walci- to he saniphd, t lien lillcd to the neck, and scfiurely stoppered. 11" the sample (ionics from a pump, the harrcl ol' the latter .should be ein|)(ied eoniplctely of I he water which has been standing in it for any lena;lh of lime; if from a pi|)c, the water .should he allowed to run to waste, until the ulioh; of the orijjjinul contents has esca|M-d ; if from a pond or other body of water, the bottle should be plunged snlllieiently far beneath the surface to avoid the entrance of (loafing matters, and at a sunieient distanc(! from th(! banks to avr»id rnatt<'r.s that \\\\\r the shore. After tlie .sain])le is secured, as littJe time as j)ossible .should elapse before bejj^inning the analy.sis, bccau.se of the rapidity with which clumg-cs occur in tlu; orijjanic matters, ammonia, nitrites, and nitratt'8. Determination of Free Ammonia and Albuminoid Ammonia. Solutions Required: 1. Standard Solution' of Amm(»mim CiiLoiiiDi;. — ^I)iss(»lve 3.138 grams of pure dry ammonium c-liloride in 1 liter of distilled water free from ammonia. One ec. of this solu- tion represents 1 mgr. of ammonia. 2. Standard Dilute Solution of Am.aionium Chloride. — Dilute 10 cc. of the strong solution u|i to 1 liter with water free from ammonia. One cc. of this solution re})resents 0.01 mgr. of ammonia. 3. Solution of Sodium Carbonate. — Dissolve 200 grams of pure sodium carbonate in 1 liter of w^ater free from ammonia. 4. Alkaline Potassium Permanganate. — Dissolve 8 grams of potassium permanganate and 200 grams of cau.stic ]>otash in 2 liters of distilled water, and boil down to 1 liter, to get rid of any free am- monia present. Fifty cc. of this solution are required for each anal- ysis. The author finds it convenient to omit the boiling-down ]iroc- ess when the solution is prepared, and to take 100 cc. and boil down to 50 at the time of analysis. This insures freedom from ammonia when used, and avoids the bumping which is so likely to occur when the cold solution is added during the process of distillation. 5. Nessler's Reagent. — Dissolve 35 grams of potassium iodide in 150 cc. of distilled water. Dissolve about 16 grams of corrosive sub- limate in 300 cc. of distilled water. Add the latter to the former, both solutions beinff cold. Then add 200 2:rams of caustic soda, dis- solved in 0.5 liter of distilled water, and mix thoroughly. Xext add, with constant stirring, a saturated solution of corrosive sublimate until the precipitate wdiich forms is permanent ; then dilute the whole to 1 446 WATER. liter. Let stand until clear, when the supernattmt liquid should have a pale-straw color. 6. Ammonia-free Water. — This may be obtained by distilling Avater made slightly acid with sulphuric acid. The first 25-50 cc. of distillate shoukl be rejected, and the next 50 cc. should be tested with Nessler's reagent. If no color appears, the distillate is ammonia-free, and the operation may then be continued until the contents of the re- tort are reduced to very small volume. If the test shows traces of ammonia, successive portions should be tested until a negative result is secured. It is well to prepare a goodly supply, and to keep it on hand in glass-st<)pj)ered bi)ttles. Apparatus Required. — Distilling Apparatus. — Some analysts pre- fer glass retorts ; others, distilling Ilasks with side tubes. Whichever is used, the connection with tlie Liebig condenser should be tiglit. The author prefers a distilling flask, with a side tube of such a size that it enters the condenser tube easily, but without making a loose joint. A bit of clean rubber tubing on the side tube may serve to make the joint more perfect at the point of entrance. The mouth Fig. 41. Distilling apparatus used in determining the ammonias in water. of the flask should be closed with a rubber stopper with a single per- foration, carrying a funnel tube which reaches to the bottom of the flask. The flask or retort may be heated either by a rose burner or by the free flame of a Bunsen lamp. In laboratories where water analysis is conducted on a large scale, it is found convenient to have the dis- tilling flasks, arranged in the form of batteries, connected with block tin condensing tubes which pass through a common cooling-tank fed by a single tap. In Fig. 41 is shown the form of apparatus which the author finds convenient for ordinary work. Dh'T/'JUJUNA'J'ION <>!<' I<'l;.l':i': and MJlllMISniH AM.\fO.\/A. 117 Nes.slerizing Tubes. — I'oi- ni.ikiiiH; \\i<'. (IclcrmiiKiiiipn i,{' atiitnonla l»y ili(! coloriiiicl ric iiiclliod, (iiIk- oI' ('(ilorlcss ^^las.^, ahoiil lli^ x jj in<;li(;H, vvidi a mark al tlic oO (•<•. |)oiiil, arc rcijnircW. Determination. -TIk' i\:\A< and coiHlin-cr arc rinsi'd with airiiiio- iila-l'rcc! \val'<'r, ().;'> lilcr of llic walcr nnd •") re. (,(' sodium carlxmaU; solill-ioii arc iiilrodiiccd inl(. ihc ll;i^-k, and lic;it i- a|i|ilicd. 'I'lic (li.s- tillai(! is cdlhM'Icd cillici- in llic .\c,--lcr tnlics or in .,iO a-. liaHk.s, Irorn wliicJi it Is (ranslcrrcd lo iIh' liihcs; and wIhii I lircc |)(M'ti()nH of 50 (i(\ each have; been collcclcd, ;dl of the free ainnioni;i in ihc samph! will iia\'(^ |)asscd o\cr. On h('i;iniiini;' (he di.-;! IMal ion, lODcc. of I he nnroiicciitraU'd alka- line permanganate! sohilion arc healed in a sin.dl lla.-l< and hoilcd down to 50 (!(!., and on (he coniiiht ion of the distillation lor free ammonia, the hot reagent is aState Board of Healtli of Massachusetts, it is the custoin to fill five tubes, and then to cea.sc distilling. 'I'o each of the tubes containing the animonia,s, 2 cc. of NessU>r's reagent are added. lu the presence of ammonia, a yel- lowish-brown color is produced, the depth of which depends upon the amount of ammonia prevSeut. Some exceptionally rich waters yield such an amount of ammonia that a precipitate is formed on addi- tion of tlu^ r(>agent. Then it is necessary to rejieat the process, and to take an aliquot part of the distillate and dilute it with anmionia- free \vater to 50 cc. before nesslerizing. Should a ]irecipitate agjiin occur, a smaller part should be taken, and so on until the proper reaction is obtained. The amount in the whole distillate may then be determined mathematically. Having nesslcrized the several tubes, the next step is to determine the amounts present by comparison of colors \vith a scale made as follows : Into a series of tubes, held in a rack, ditferent amounts of the M^eaker solution of ammonium chlo- ride are introduced, then ammonia-free water is added to each up to the 50 cc. mark, each tube inverted to insure thorough mixing, and, finally, 2 cc. of Nessler's reagent added to each. A convenient scale is secured by using 0.25, 0^50, 0.75, 1.00, 1.50, 2.00, 2.50, 3.00, 3.50, 4.00, and 5.00 cc, representing 0.0025, 0.0050, 0.0075, 0.010, 0.015, 0.020, 0.025, 0.030, 0.035, 0.040, and 0.050 mgr. of ammo- nia. The first of these will have a very faint yellowish-brown tint, and the last a very decided reddish-brown color, while the intervening tubes show a progressive deepening. With these tubes, the distillates are compared, and the matching of colors gives the desired results. If a given tube falls betw-een any two of the scale, a new comparison 448 WATEB. tube may be prepared ; but the practised eye can determine very accu- rately ^\'ithout this extra aid. Having read the cok^r of each tube, the amounts of th(\>^e representing the free anunonia are added together, and the total multiplied by 2, to get the amount per liter of water ; the same process is carried out for the determination of the albu- minoid annnonia. The results represent parts per million, since 1 liter equals 1,000,000 milligrams. ExAJiPLE. — The three free-ammonia tubes show 0.023, 0.006, 0.000 :totiil 0.029 mgr. ; multiplied by 2 = 0.058 per liter. By moving the decimal point one place to the left, we have 0.0058 part per 100,000, in which terms the results ordinarily are ex])ressed. Precautions. — Since the depth of color caused by Nessler's reagent is atitected more or less by temperature, and since in all processes of comparison the conditions must be the same so far as is possible, the reagent should not be added until the distillates and the contents of the comparison tubes have the same temperature. Equality in this respect is secured without any manipulation or trouble by leaving the tubes over night, so that all will acquire the temperature of the room. It is hardly necessary to point out that the air of the room in which the distillation is conducted should be quite free from laboratory fumes, such as ammonia and sulphuretted hydrogen, which, being absorbed by the distillate, would, in the one case, give erroneous results, and, in the other, react upon the mercury salt iu the Nessler's reagent. The heat applied to the distilling flask should be so regulated that the time required for each portion of 50 cc. will be about fifteen minutes, since with more rapid distillation there is likely to be some loss of ammonia by imperfect condensation. The reading of the tubes should not be undertaken until at least five minutes have elapsed after the addition of the reagent. The extreme depth of color obtainable is reached somewhat Avithin that time. The practice of some analysts of distilling the free ammouia out in one lot of 150 or 200 cc, collecting the albuminoid ammonia in another single portion of 200 or 250 cc, nesslerizing a portion of each, and calculating the total amount of each by multiplication by the proper factor, gives correct results ; but it has been shown that by pro- ceeding in this way, one may lose useful information obtainable from a knowledge of the rate at which the ammonia is evolved, since organic matter, well advanced iu decomposition, yields it more copiously in the first distillate, whereas fresh material yields it more slowly and uni- formly. Some analysts make duplicate distillations of one water at the same time, determining the free ammonia in one sjDCcimen, and, by add- ing the permanganate at the start in the other, determining the total free and albuminoid ammonia together. By subtracting the lesser from the greater, the amount of albuminoid ammonia is obtained. DI'JTI'JIiM I NATION OF F/ih'/': AND A I.IHJ M I NOl l> AMMONIA. \V.) Permanent Ammonia Standards. In onh't- to uvoid tlu- nocx*m\{y of |)r('|»:u'iii;4' si;iii(l;ir(ls cncli liin.' llus' .'iiv rc(|iiin'. .l.i'I; -'-n ' li;is propoHcd rii:dernianent hrijrlit red. With a little practice, the e.\a<'t depth of color can Ik; easily duplicated. It will take a little over lOO cc. ol" the mercuric (•hloride solution to reaeh this end point. Dissolve the red precipitate l»y add- iuo- e,\a,ctly O.TT) I<<'('|> I'Ik- IiiIx'S corked or otiicru !.-(■ |)rr,tcct('ht- yellow color^ the intensity of which depends upon the amount of nitrate present. The comparison of tints may be made directly in the porcelain dishes or in tubes of the same sort as used in the nitrite deterniination. The accuracy of the test is diminished ))y the presence of chlorides in notable amounts, say more than 2 parts in 100,000, but not by nitrites. On this account. Mason recommends the addition of cor- responding amounts of sodium cliloridc in the jjreparation of the color scale. The standards made as above do not change on keeping, and hence may be made up in sets and preserved. Determination of Chlorine. — Solutions Required. — 1. Standard SoLUTiox OF Silver Xitrate. — Dissolve 4.797 grams of pure silver nitrate in 1 liter of distilled water. One cc. of this solution is the equivalent of 1 mgr. of chlorine. 2. Solution of Potassium Chromate. — Dissolve 5 grams of potassium chromate in 100 cc. of distilled water, add nitrate of silver solution, for the removal of any traces of chlorides present, until a red precipitate of chromate of silver is formed. Let stand, and separate the precipitate by decantation or filtration. This solution is to be used as an indicator. Process. — Place in each of two beakers of similar size 100 cc. of water and 5—10 drops of the indicator. The beakers standing side by side upon a w^hite surface of porcelain or filter-jmper, the silver nitrate solution is added to one of them from a burette little by little until, in spite of stirring with a glass rod, a faint reddish tinge begins to be perceptible. This is seen more easily by comparison with the water in the other beaker. The burette reading is now taken, and then a drop or two more of the reagent Avill, by intensifying the red color, show that the end point has been reached. The process depends upon the fact that silver has a greater affinity for chlorides than for chrom- ates, and that, so long as any of the former is present, no permanent union will occur with the latter. When, however, all the chlorine has combined with the silver, the red chromate begins to form, and makes its presence known by the change of color. On completion of the process, the amount of the standard reagent used indicates the amount of chlorine present, each cc. used representing 1 milligram. Inasmuch as a certain amount of the reagent is required to give the beginning tint in 100 cc. of distilled water, a correction should be made before setting down the result. This amount differs somewhat with different observers, since all eyes are not equally quicsk to discern the appearance of the reddish tint, and hence the best method of fixing i)i ammonia. 1.",:', th(i iiiiioiiiil U) l)(! Hiil)l riidcd is (ur c'lcli one In (IflcnniiK' il, liimsc-ir hy (!X|K'riiiiciil.iiilillc(l \v:ilr llic iii(li<-:iti)i'. Should tlic ;iiii()iiii( dl" cliliirinc in ;i ^ivcii ?-;iiii|»lc he sn miiiiII that [\\{\ end r(!!i(!li<>ii ii|)|)(!;ii's on the jiddilioii of hiil. a fi'W drops of" tfu; .silviM" sohidon, il. is best in coiiccnl r.ilc UoO or oOO cc. of (h*; water to 100 ('.{'.., and r-cpcal. the titration. Determination of Residue. — I'lvaiioratc loo cc. of water to dry- ness in a, perfect ly eiean, (h-y, aeem-ately w'eij^hed platinnni di.-h. When c!onij)IeleIy evaporated, transfer the dish from the water'-hath to an air- hatli kept, at l()r)°('., and leaAc it for an hour, at, the expiration of which time, |)la(te It, in a desiccator to cool. |{ew'ei;^h and not nitrates, nitrites, ammonium salts, combined carbonic acid, and, if the tem]HM'ature has been raised too far, part of the chlorides. The residue after ignition represents the "fixed solids." Determination of Hardness. — For the determination of hardness, a number of processes are in use ; but for practical utility, that known as the "soa]) method" is to be preferred. Solutions RecLuired. — 1. Standard Solution of Calcium Chlo- RTDi:. — ^^V^gh out l gram of pure calcium carbonate, dissolve it in as little as possible dilute hydrochloric acid, and evaporate to diyness. Add to the residue a little distilled water, and again evaporate to dryness. Dissolve in distilled water and make up to 1 liter. One cc. represents 1 milligram of calcium carbonate. 2. Standard Solution of Soap. — Scnipe about 10 grams from an old dry piece of pure Castile soap free from sodium hydrate and carbonate, and dissolve it in 1 liter of diluted alcohol. Let stand over night and filter. This should next be standardized in the following manner : To 100 cc. of distilled water contained in a glass-stoppered bottle of about 250 cc. capacity, run in, from a burette, successive small portions of the soap solution until, on vigorous shaking, a lather is formed which persists at least two minutes, and note the amount used. Repeat the operation with 99 cc. -j- 1 cc. of the standard solution of 454 WATEE. calcium chloride, and then with 2, 3, 4, 5, 6, 7, 8, 9, and 10 cc. of the same solution made up to 100 cc. with distilled water, and note the amount used in each test. It will not suffice to determiue the amount necessary to produce a lather with distilled water and with 10 cc. of the calcium chloride solution, made up to the same volume, ami divide the diiference by 10, since as we go up in the scale a gradual lessening of the amount of increase for each degree is noted. In this way we obtain a scale of values for the particular lot of soap solution made at one time. It will save some trouble if one makes up a number of liters, but it is necessary to make occasional tests to see that the strength does not deteriorate, or, if it does, to correct the scale. Process. — To 100 cc. in the bottle above mentioned, add the soap solution in the same manner as employed in making the scale, and, when the end point is reached, note the amount used, and, by reference to the scale, ascertain the number of degrees of hardness. Should the water be harder than 10 degrees, it is best to take a smaller amount and make it up to 100 cc. with distilled water and then proceed anew, remembering at the end to calculate accordingly. The result obtained expresses the "total hardness." If it be desired to ascertain the temporary, or removable, hardness, 100 cc. of the water may be boiled five minutes and then allowed to cool. The original volume is restored by the addition of the necessary amount of distilled water, and then the operation is repeated. The second result indicates the permanent hardness, and the difference, if any, is the temporary hardness. Determination of " Oxygen Required." — All organic substances are susceptible of oxidation ; but as they are widely variable in character, they require very different amounts of oxidizing agents for the attain- ment of the same result. The several methods proposed for determin- ing the oxygen-consuming capacity of drinking-waters have, therefore, only a limited value ; but, in general, it may be said that a high require- ment indicates an amount of organic matter inconsistent with purity when it cannot be accounted for by the presence of ferrous salts. Since the amount of organic matter is indicated pretty fairly by the ammonia and albuminoid-ammonia determinations, the estimation of the " oxygen required " serves only as confirmatory evidence. Solutions Eequired. — 1. Standard Solution of Potassium Per- manganate. — Dissolve 0.395 gram in 1 liter of distilled water. One cc. is equivalent to 0.1 mgr. of available oxygen. 2. Standard Solution of Oxalic Acid. — Dissolve 0.7875 gram in 1 liter of distilled water. One cc. corresponds to an equal measure of the permanganate solution. 3. Dilute Sulphuric Acid, 1:3. Process. — The determination is based on the fact that potassinm permanganate gives up its oxygen readily to organic matter, especially in the presence of acid and with the application of heat. The reaction is expressed in the following equation : 4KMnO, + 6H,S04 -- 2K,S0, + 4MnS04 + 6H,0 + 50,. DMri'lfiMf NATION OF FH/'H': AND A Li: I ! M I NOI I) AMMONIA. 155 TluiM 4 inolcciilcs (»(' |»crm;iii^uiiiil<' will \ I'M ■> <>(" ow}z;i-ii, «.r, dilliir- enlJy r made (it for use by boiiiii;;- it. in distilled water aeidiilaled willi siil|iliiirie aeid, and addiiij;- |)erinaiii;aiial(; solution iiiilil no fnrllier deeoloratioii Ih ()l)S(H"ve(l. VVm'v. 200 rv. of ilie sample in tlie di.di, add 10 ee. <.f lli<- dilute siil|)liuri(! iicid, and heat (o hoilinj;-. Add from a biirelfe siillieienl of \\\v. |)erman<;analc solution to cause a very distinct redness, and boil aj^aiii, addiiit;' \\n'. |)eriiiantj:;aiiate as tlie e<)|or lend-, to lade, so as Ut rclaiii as nearly as possible tlie orieinal color. When (intlier boiling for livctotcn minntes fails to diminish the iiilen.--ity of the color,oxida- tion is complete. Add now 10 ce. of the oxalic acid solution, which will di,scliar}«;o tlu; vaAov if the peiMiani;anate ha.s not been added Uh) freely. Should the coloi- not be discharfred by 10 cc, add 10 more. Tlavini*; now a, colorless solution, add more pennanwing a sulhcient depth of the specimen in a glass cylinder against a white surface. Color may be expressed quantitatively by comparison with the standards for the ammonia determinations. Determination of Odor. — Place about 200 cc. of water in a 500 cc. beaker, cover with a watch-glass, and heat to about 40° C. Give the beaker a rotary motion, so that the water is set in motion, remove the watch-glass, and with the nose well inside the beaker note the character of the odor. Some analysts prefer to heat the water in a glass-stoppered bottle, the use of which permits a nuich more thorough agitation of the water before applying the nose. The odor should be designated according to the substance which its presence suggests. Determination of Reaction. — A most delicate reagent for alkalinity in water is a 1 per cent, solution of toluylene-red. Fifty ce. of water 456 WATER. distinctly alkaline will become intensely yellow on the addition of 2 or 3 drops. A less deji'rec of alkalinity will cause an orange or pale- red color. It is so delicate a test that 1 part of alkaline carbonate in 1,000,000 is revaded by it. The presence of acids is shown by another sensitive indicator, lac- moid. This is not affected by carbonic acid, nor by ferrous and other metallic salts which are acid to litmus, but is aifected by ferric salts. It may be used as a 1 per cent, solution in diluted alcohol. Phenol- phthalein solution, 0.5 per cent., is colorless in neutral and acid solu- tions, and pink in alkaline. It is aifected by carbonic acid. In the determination of reaction, a drop or two of the indicator may be added to a volume of the Avater in a long glass tube. A very faint change, due to acids or alkalies, is perceptible on looking down through the column against a white background. If the reaction is acid, the sample should be boiled, then cooled, and tested again to ascertain if the acidity is due wholly or in part to carbonic acid. Acidity and alka- linity are determined quantitatively by titration Avith centinormal solu- tions of sodiuin hydrate and hydrochloric acid, using lacmoid or phenolphthalein and methyl-orange as indicators. Determination of Turbidity. — For the determination of the degree of turbidity, several methods are in use, among which the following may be mentioned : Mason ^ recommends standards made by adding weighed amounts of kaolin to distilled water, each representing parts per 1,000,000 of kaolin. Whipple and Jackson^ employ finely powdered diatomaceous earth, instead of kaolin, because of the greater uniformity in the size of the particles. Hazen ^ measures it by determining the depth at which a 0.1 mm. platinum ware can no longer be seen. Detection and Determination of Lead. — Many processes have been proposed for both qualitative and quantitative determination of this most undesirable contamination. The simplest test, but by no means the best, consists in adding a drop or two of ammonium sul- phide to a volume of water in a tall glass cylinder, and noting the character of the discoloration produced. If darkening occurs, due to the formation of a metallic sulphide, the addition of dilute hydrochloric acid will distinguish between lead and iron, the sulphide of the latter being soluble. To those who have had practical experience in de- tecting minute amounts of metals in water, this method is far from satisfactory. More or less color is imparted by the ammonium sul- ])hide, and more or less turbidity is produced commonly on the ad- dition of the acid. Moreover, when unconcentrated water is used for the test, no reaction may occur, although the poisonous metal is present in minute traces. Another simple test, depending upon the formation of lead chromate, has been offered by S. Harvey,* who claims that water containing 0.30 ' Journal of the American Chemical Society, XXI., p. 516. 2 Technology Quarterly, XTII., No. 3, September, 1900. » Journal of the Fi-anklin Institute, 1899, p. 177. * The Analyst, April, 1890. DI'ITHIIM I NATION OF FIIKE AND ALIUIMINOIl) AMMONIA, l-'j? iiiilli;i,r;iiii (»(' lc;ul in I liter will show :i liiihidil y IVorn (•liroinnte \vli<-n '250 {•.{',. ■A.vr. ti'c.'ilcd vvilli 0.10 ^I'miii oI' |»f)f;i.~siiiiii hiclirf)iii:il<' ; and that in tw(!lv(; hours the | tree! pilule will -d t !<• ;ind licconHr si ill tuorc dislinr-f . Since; small ainoiinis idl< hefon; a,tt(Mn|)tiniif to |)re(ri|>ilalc (he lead. IVom I his point onward the nudhods ('m|)loye(l \ary xi'vy eousideralily. Li(!l)i'i('Ji ' precipitates llie lead as sulphide in acid solution, coiivortrt it to sulphate l)y tn^atuK^nt with nitric and sulphuric acids, and and made up to 20 c(^, and 2 vr.. of" anuuonium sulphihide water of good strength. Any lead })resent is preci])itated in a very fine state, but not so fine but that the entire amount can be collected on II Swedish filter. AVash twice, and then treat on the filter with boil- ing dilute nitric acid until the black deposit is wholly dissolved. Wash with hot water as long as the washings are acid, and add them to the nitric acid filtrate. Evaporate to dryness in the original dish, add dis- tilled water, and again dry. Dissolve the residue in hot distilled water and make up to 50 cc. Take 5—10 cc. and dilute to about 80 cc. with distilled Avater in a glass comparison tube of 100 cc. capacity, add hydrogen sulphide water in sufficient amount, make up to 100 cc. with distilled water, and mix thoroughly by inverting the tube a number of times. Compare the depth of color with those of a series of tubes containing known amounts of lead as lead nitrate, treated with hydro- gen sulphide in the same way. The standard solution is made by dissolving 0.160 gram of pure lead nitrate in 1 liter of distilled water: 1 cc. represents 0.1 milligram of lead. A convenient scale is made with 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 cc. of the solution in 100 cc. If the hydrogen sulphide water is added after diluting to about 80 cc, the result is a series of sufficiently clear standards showing sharp and regular stages of color. If the reagent is added before the lead salt has been sufficiently diluted, the standards are very turbid, and are lacking in the very essential grada- tion of color. Should the depth of color obtained in the preliminary test be greater than that given by No. 10, a smaller amount should be taken and the experiment repeated. Should the color be very faint, the whole of the remainder may be treated and compared. From the result obtained by matching the colors, the amount of lead in parts per 100,000 is easily calculated. Example. — Ten cc. treated as above gave a color reaction midway between standards 6 and 7 ; hence, one-fifth of the whole contains 0.65 milligram of lead, and the entire amount contains 3.25 milligrams. The amount of water concentrated was 3 liters. Hence 1 liter of water contains 1.08 milligrams, and 100 cc, or 100,000 milligrams of water, contain 0.108 milligram of lead. Detection of Zinc. — One is reasonably safe in assuming that water which has ]>een in contact with galvanized iron will show the jirescnce of zinc. This may be determined quantitatively by evaporating a INFEIIKNCI'IS AS '!'() (HI MiAC'ri'.li (fF WATF.Il. 459 qiiiiiilKy oC \v;ilcr lo ;i .sniiill liiills, licjiliii^'; IIk- I.iII llMI-dllcSM I.'H) A|ipciii;iiicc, <'li:ir :iiiil lirifjhl. ( Idlor, iiliHciil. ( )di)r, mIwciiI. ( 'li.llincs oliscrvct it iirnls. 'I'licrc is no sii^}i;(!s(.i()ii ol" coiilniiiiiKil iiHi of ;iiiy kiii4 Ciiloriue 4.27 Volatile residue 11.10 l<^ixed residue 23.30 'I\.tal residue 34.40 Hardness 14.00 Appea ranee, clear and lirinlit. Color, al)sent. Odor, I'oul alter lioalinc;. Changes ohserved on ii^Miilion of residue, sliylit Vjlackening. These results, which are actual ones obtained from a sj^eeimen sent to the author with no statement of origin, warranted a report of gross pollution, regardless of source, for the presence of sewage mat- ters was undeniable, and under no circumstances of geographical loca- tion could any other report be made. Inquiry concerning the origin of the water brought the informatiim that the M'ell from -which it came was located at no great distance from a leaching eessjxtol, and was used only when the usual source of supply, a spring, ran dry. Repeated attacks of illness of no great seriousness had been noticed whenever, during the preceding three years, this Avater had been used. These two waters may serve as good examples of uiuhmbted purity and extensive pollution. Both are ground- waters, and, Avhat is not without interest, they came from one and the same small inland town. Such results as the above require no long consideration — they S]ieak for themselves. But it very commonly happens that even a single ingredient may cause susjiicion of sewage p(^llution to arise when information as to the location of the supply is withheld. Thus, the amount o'i chlorine may be very considerably higher than the lowest normal commonly observed inland, and yet well under the amount which excites no adverse comment in a water from the coast. Thus, 3.85 ]iarts in a well-water from an island in Btiston Harbor, and 1.35 in another from the bonlers of Long Island Sound, may be regarded 462 WATER. as fairly low ; while if found in s]nnni2:.s in the Green IMonntain range, they would be most aljuornially high and of much signitieance. Again, such an amount might come in connection with fair yields of the ammonias, and then under one class of conditions the organic matters Avould apjx'ur to be of vegetable origin and in another to be a part of sewage. It IS also impossible to draw shar]i dividing lines between small, considerable, and high amounts of the ammonias ; but, in general terms, it may be stated that up to 0.005 or 0.006 part per 100,000 may be regarded as low, from thereabouts to 0.015 or 0.020 as con- siderable, and beyond as high. Measurable amounts of nitrites are most significant, while nitrates may run up to several Mdiole parts per 100,000. Thus, it may readily be understood that, in the major- ity of cases, the results should be considered in conjunction with all material facts connected with source, surroundings, and opportunity for receiving pollution. Bacteriological Examination of Water. The bacteriological analysis of water may be divided into quanti- tative and qualitative determinations. The former is commonly ex- tended over long periods, and has for its object the determination of the normal bacterial content of a given w^ater supply and the observ- ance of any unusual variation therefrom ; while the latter is pursued for the purpose of determining the nature of the organisms, and, more particularly, whether they are such as are to be found in the excreta of the body. The finding of such does not mean necessarily that the use of the water will inevitably produce disease, but it indicates the possibility and probability that water containing non-pathogenic organ- isms from this source may, if not to-day, to-morroM', or later, become infected \vith others from the same source, capable of acting as the exciting cause of grave disaster. As is the case with chemical analysis, it is impossible to fix any standard of safety based on the mere amount expressed by the quantitative results, since it is the nature and not the amount of the contaminating matters which determines the question of pota- bility. But sudden deviations from the seasonal normal suggest unusual access of contamination, and serve as warnings of possible danger. The isolation and systematic study of the various species of bacteria in a given water to determine whether or not they may be patho- genic, involve much labor and an intimate knowledge of bacterio- logical technic which can be acquired only by thorough training in a bacteriological laboratory. Familiarity with the methods of pre- paring culture media -and making cultures, of isolating species and studying their characteristics, is, therefore, a necessary qualification for the pursuit of bacteriological examination of water, and anything more than a brief outline of special methods employed in this par- iiA(;'ri':iu()iJ)(ii(:.\L I'-.xamisatios of wateh. 4- cojic ()(■ ;i \v <)l).s(!rvoinl and sr;dcd liv (ilosnrt- in a lamp llamc, or in lioillcs ofaUonl, police, c'l |)acit \' willi ;.!ronnd stoi)])!'!-,-. Tlu' liniijs arc made. casiU' !>>■ an\'l)odv who lias lialcrile forceps. The hull) is filled partly almost imniediaIeK', and (hen ihc hroken point is sealed as hc- i'oro by the application of heat from a L;as (lame or alcohol lamp. If" hottlcs ar(> nsed, they should (irst he washed on the outside in the water (() he sampled, and then plnnL:;ed heiieath the siirfac*-. The Kt()])pc'rs aiv then withdrawn, and, when lilliii<:; is completed, ihey are replaced. If any considerahle time must elapse before cultures can be made, the samples should be |)acked in ice, iu order to retard multiplication of the coutr.ined bacteria; and since very low tem])eratures have no harmful influence on the vitality of the organisms, the addition of a small amount of salt to the ice may be of advantage, although freezing should not be permitted, on account of the danger of bursting the eon- taiucrs. Planting the Samples. — If i)ossible, the ]>]anting shf)uld be accom- plished on the spot, on account of the multiplication which is inevitiible with delay. If this is not j)ossible, no greater delay should be per- mitted than is absolutely necessary. For (qualitative determinations, two sets of plates should be made : one on reaular amir and one on litmus lactose arrar. On the second and third days the regular agar plates should be looked over, and any which show bad spreaders or a number of colonies so large that danger of obscuring the count would result if they were inen bated longer should be transferred to the refrigerator. On the fourth day all the regular agar plates should be removed and counted. The tcmpcratin*e at which they should be kept is 20° C. The litmus lactose agar ])lates should be incubated at 40° C. for 18 to 24 hours only, after which they should be removed for counting.^ \Mien w'orking on a water of unknown character hitherto uncxam- inetl, ditfereut amounts of the sample — 1, 2, 3, and more drops — should be used, since one cim have no deiinite idea of its bacterial richness. 1 IVrsonal oonimmiioation from Mr. II. W. (^lark, chemist in charge of the Lawrence Experiment Station of the Mas§acliusetts State Board of Heahh. 464 WA TER. In quantitntivo work, the nniouiits taken should be measured with the irreatest aceuraey, es]X'eially N\hen preliminary determinations have sho\vn sueh a number of organisms as to make great dilution with sterile A\ater necessar}-, for any departure from absolute accuracy introduces an error which will be multiplied according to the degree of dilution. When bull) tul)es are used, their contents are expelled with the aid of gentle heat, Avhich causes the small amount of contained air to expand and force the liquid through the stenij which is broken at the point by pressure from sterile forceps. The expelled water is received in a sterile tube, from A\hieh it may be withdrawn in a sterile graduated pi])ette. Quantitative Determination. — The value of quantitative determi- nations lies in the eouq)arisons which one is enabled to make from a series of periodical examinations of the same water, for the information to be derived from a single examination has very limited utility. By means of periodical counts, one is enabled to form an idea of the con- ditions normally present under different circumstances, and to note at once any disturbing influence. Quantitative determinations are of special value in noting changes in the efficiency of sand filtration of public supplies. Knowing from preliminary tests or from past experience how much water should be taken for each plate, and the degree of dilution neces- sary, two sets are made, one on regular agar and one on litmus lactose agar, and the growths allowed to develop, llegular agar cultures are kept at 20° C ; the litmus lactose agar plates are kept at 40° C. The lower of these two ranges of temperature is much more favorable to the multiplication of ordinary water bacteria than the higher, and conse- quently it will be found that the colonies developing on the regular agar will be decidedly more numerous than those on the litmus lactose agar. In expressing results, therefore, mention should be made of the culture-medium employed ; and in making comparisons of one day's results with those of another, the importance of limiting them to figures obtained under like conditions of culture-medium and tempera- ture is too obvious to need further mention. In counting colonies the following method is pursued at the Law- rence Experiment Station : The plate is placed on a glass plate ruled in centimeter squares, a modification of the Wolffhiigel counting frame, and the number of colonies is counted with the aid of a four-inch reading-glass. The total number of colonies on the regular agar plates, and both the total number and the number of red colonies on the litmus lactose agar plates are counted, the results being entered upon the record slip, to- gether with the date and the initial of the bacteriologist who makes the count. On plates containing less than 300 colonies all the colonies are counted. On ])lates containing more than 300 colonies a fractional part of tlie plate is counted and the result multi])lied by the proper factor. On plates containing l)etwc('n 300 and 800 colonies one-half of the plate is counted. On plates containing more than 800 colonies I'.Ad'ri'Huoi.ocidM, I'.xAMisA'rios or w.\ri:ii. 105 a line acroHH, /. r., ;i stri|» (nic cciitiirHlfr wific tlir<.ii'_-li thr- ttiiiMIc <>{' the plate, is coiinlcd, wliilf le atta(:ljc} ])latin<:: out and is(»lati(»n of the pure cultures, (c) identitieation or (!onfirmation of the cultures. {(i) The preliminary tests are of two kinds, those made iu fermen- tation tubes and those made in bottles. The fermentation tube tests arc made by introducing 1 cc, or a fractional part oi' 1 cc, of the water under examination into a fermentation tube containing dextrf)se peptone solution. This is conveniently done at the time that the water is i)ipetted into the plates during the process of plating j tests of larger volumes than 1 cc, usually 100 or 1000 cc, are made in bottles, 10 per cent, by volume of pheuolated dextrose peptone solution being mixed with the required volume of water iu a glass-stoppered bottle. The fermentation tubes and bottles are incubated over night at 40° C. In case fermentation occurs in the tube, it will be manifest by a collection of gas in the closed arm. In case no gas is observed, the bacteria of the colon type are not present and the test is com]>lete. The tests in larger volumes, upon being removed from the incubator, are given one quick, hard shake and held up toward the light. In case active fer- mentation has occurred, the gas will separate from the liquid and rise slowly, giving the same a}>pearanee as when a bottle of highly carbon- ated water is opened. In case the shake test is negative, it shi^uld be confirmed by placing about i cc. of the culture in a fermentation tube with dextrose peptone solution and incubating 24 hours. When making the preliminary tests, a record slip or day card is made, upon which each sample tested and the results of the tests are indicated by plus and zero signs. Final record slips, containing the name of the sample, the date, the volume of the test, and its result are made from the day ^ Pei-sonal communication from ^Ir. II. W. Clark, chemist in charge. 30 466 WATER. card after the tests are completed, the volume tested, and the result being placed in the upper right-hand corner of the slip, the date in the center at the top, and the sample number in the U])per left-hand corner. (6) The positive tests, either in fermentation tubes or in the bottles, are now plated out on litmus lactose agar. The record slips of the positive tests are arranged on the plating table, and sterilized Petri dishes, each .containing 5 drops of litmus solution, are placed thereon. With a straight, sterile platinum needle a minute quantity of the pre- liminary culture is transferred to the litmus, the plates are poured with lactose agar, placed in the refrigerator for one hour, turned, and incu- bated 24"hours at 40° C. (c) On removing the plates from the incubator they are examined to determine whether or not red colonies have developed. In case no red colonies have developed, the result is negative, and is so recorded on the slip. In case red colonies are present, two colonies from each plate are transferred with a sterile, platinum needle to agar streaks, the agar streaks being incubated 24 hours at 40° C. After incubation the characteristic colon streak should be luxuriant, smooth, white, and glossy, and should not be stringy to the needle. Tubes showing a very scanty growth of small colonies following the track of the needle are examined under the microscope for the presence of streptococcus forms. They are not B. coli. Tubes which are stringy to the needle or which show a wrinkled growth are also not B. coli, and are recorded as nega- tive, and tubes which show no growth at all are so recorded. From the tubes which show the characteristic appearance of B. coli transfers are made with a loop needle to a fermentation tube containing dextrose peptone solution to tubes of nitrate solution, Dunham's solution, and with a straight needle a stab culture is made into a tube of gelatin. The fermentation tubes and tubes of nitrate and Dunham's solutions are incubated at 40° C. — the first two for 24 hours and the Dunham's solution for three days. The gelatin tubes are incubated at 20° C for fourteen days. At the end of 24 hours the fermentation tubes are examined for the presence of gas in the closed arm, and the nitrate tubes are tested for the presence of nitrites with the usual Griess re- agents. At the end of three days the Dunham's solution tubes are tested for the presence of indol by adding 1 cc. of 1 : 1 sulphuric acid and 1 cc. of a solution of potassium nitrite containing 0.02 of 1 per cent., the presence of indol being manifested by the appearance of a pinkish or purplish coloration. The gelatin tubes are examined on the fourth, seventh, tenth, and fourteenth days for the occurrence of lique- faction, the form of liquefaction and the date on which it occurred being recorded in case it is observed. In recording these tests no record is made of tests which are characteristic of B. coli, i. e., if fer- mentation occurs, nitrites are formed, indol is produced, and no lique- faction occurs, the culture is finally recorded as of the colon type. In case any one of these tests is negative, it is repeated with the same cul- ture before being recorded, and in case a second negative is obtained, the negative record is made, and the culture is recorded as not of the ColoD type. These records are conveniently made in a book ruled for COMry\llA'l'IVI': VALIII': OF ANALYSIS OF DiirNKINd -WATFIl. MM llic i)iir|)OHc, (lie hI rc;il< ('iilt iiiv.-, liciii;.,' niimlifrcil >ci'i;illy, ;i rc'Of'l <>{ tlic, s;iin|)l(', hl;iitH'«l Ixiii^ rc'c-oidcd ill (lie Itook ;i.f llic tinu! (lie stn';il< (iiiltiircs wen- iiiMdr-, iIk; tubes of" (',oii(ii"iii:it«)ry nirdin bciii*.'; carried fliroii^di \\\Ai-v llif -eri.d nnnihcr. It is iisnal to rack Uj) llic streak eiilliires in order and (isli to coiidrniiitory iiiedin !i( convfiiiicnl iiitcrvalH. As soon as the fernien- tation, Tiitrjilc, and iiidol lesls an; cotiiplete, tlu; streak enltnres may hf; (kfstroyod, since tluy may l»e recovered, if necessary, at any time williin fourteen days IVoin (he ,indi(!e against and contenipl for any opinion as to the jiota- bility of a particular water based uj)on chemical analysis, maintaining, quite correctly, that minute amounts of ammonia, albuminoid ammf)nia, and clilovine are incapable of actinjr as the excitinj^ cause of infective disease, and that not these substances, but only specific orrted by a chemist of high standing as of great purity and eminently suitable for domestic purposes. Such a test, however, is unworthy of the slightest consideration, since under natural conditions a water showing a high degree of chemical purity is not likely to be infected with a })ure culture of a pathogenic organism, and the submission of a pure water st) treated is a mere trap, the setting of which is no more praiseworthy than Mould be the sending of a sterile solution of cyanide of potassium or of sulphate of strychnine to a bacteriologist Avith a request for an opinion from the standpoint of his specialty as to its desirability as a beverage. Chemical analysis can show the presence of organic and mineral impurity such as accompanies infectious matters from the intestine and bladder. It caimot give grounds for a positive assertion that the use of a water thus polluted will inevitably cause disease, but it can and does serve to point out possible danger. It can detect the presence of sewage matters, and while it cannot jirove the presence of infectious material therein, it can at least point out that the occurrence of typhoid 468 TIM TER. fever in the eoiinmniity t\irnisliini2; the sewage is likely to be followed by other eases of the disease in the community whieii uses the polluted water. It cannot distinguisli typhoid pollution from any other excremental con- tamination, since a healtiiy body yields the same chemical substances as one that is diseased. In the case of waters containing no evidence of contamination, it can supply the basis of an opinion as to safety, but it cannot furnish any guaranty that the condition is pennanent. Bacterioloo;ic^d analvsis differentiates between ijathotienic and non- pathogenic contamination, but it is only rai'ely that it serves to point out danger in advance. Even when an outbreak of typhoid fever has occurred and attention is drawn thereby to the condition of the water sup])ly, the results of bacteriological examination are generally negative. The reason for this is twofold. In the iirst place, the examination for the detection of the specific organism is not ordinarily begun until attention is drawn to its necessity by an outbreak of the disease, which does not appear until about two weeks from the time contamination has occurred. Unless the contamination is continuous, by the time the examination is instituted, the polluting materials have either passed on or the specific organisms have perished. In the second place, even although they are jiresent, A\ith our present methods it is not an easy matter to isolate them, and we can determine in most cases only the probability of their presence. It should be borne in mind that the organisms are particulate bodies in suspension in great dilution, and that their distribution .is not homo- geneous as is the case ^^•ith substances in solution, and that, therefore, the amount of water taken for planting plates may not contain them. But in the unsuccessful search, it is not uncommon to find B. coli com- munis, and where this organism lurks, the other may have been present. As a rule, bacteriological search for the typhoid bacillus has given negative results. Laws and Andrews failed to find it in the sewage of London, although it must have been present ; and they had but slight success in the examination of sewage from a hospital where forty cases of the disease were being treated. The reason for this may be that through absence of suitable food material and favorable temperature, and bv reason of the antagonistic influence of the ordinary sewage bacteria, the typhoid bacilli had lost their vitality ; or it may be that they were so diluted that the volumes used for planting failed, as a rule, to contain them. Examination of the water supposed to be con- cerned in the unusual outbreak at Maidstone yielded absolutely nega- tive results, although no reasonable doubt can exist that at some time they had been present. Professor Percy Frankland, Avho has had a large experience in dealing with micro-organisms in air and water, says : ^ " The detection of specific pathogenic bacteria in drinking-water is now know^n to be almost beyond the range of practical politics, and the search for such bacteria is, in general, only carried on in deference to the special request of the layman, the uninitiated, or the hopelessly ignorant, whilst it can- not be repeated often enough that any feeling of security which may ^ Journal of the Sanitary Institute, October, 1899, p. 393. r!OMrARA'i'fv/<: vaijim of analysis of Dniyh'isa-WATFit. \r,'.) he jjiinilicrcd fVotn :iii iirisiKTcssriil H(!iircli (<»r piit lioijcnic h.-icfcriji in wliolly illiisoiy jiikI ill llic lii}:,li('Ml. (Ic^rcc (l;iii;iiial ijurity an; eonccnied, hee(»nies more ;ind nioi'e dinieult, adolated responded to every test, includinu; gi'owtli on gelatin, potato, litmu.s milk, houillon and glucose bouillon, agglutination, and Pfeiffer's test with animals, is re(U)rik'd by Drs. Kiibler and Nenfeld.- In tliis case, the cause of the disease lay in the use of water from a \vell infected by the urine of a person sick with the disease. Four weeks from the time of the first examination when the bacillus Avas isolated, a .second analysis was made, which yieldcMl b;icilli which res])onded to all the tests excepting Pfeitfer's, wdiich excei)tion w^as supposedly due to modi- fied virulence. No colon bacilli were present either time. A second instance is recorded by Fischer and Flatau,'^ who isolated the organism from a well-water in Ivellingen. Similarly, a second attempt, made four weeks later, was unsuccessful. G. Mayer ^ claims to have isolated typhoid bacilli ''massenhafl" from well water. Jackson and INIelia'' were able, by the use of lactose bile media, to isolate the typhoid bacillus from — (1) Grass River, a S(Hirce of water supply for Canton, New York ; ( 2) from a pond or stream used as a private water supply at Hastings, New York ; and (3) from two points in the Hudson River. Nevertheles.s, it still remains true that the isolation of the typhoid organisms from suspected water sup- plies is very rarely accomplished. From what has gone before, it may be said that neither chemical nor bacteriological analysis is infallible. Each has its uses, and each may be helped by the other. The value of either lies in the skill displayed in interpreting the results, and this requires as much knowledge as the making of the examination itself. 1 Bacteriological Exaniination of Water. London, 1901, p. 3. 2 Zeitschrift I'iir Hygiene und Infectionskranklieiten, XXXI., 1899, p. 133. 3 Centralblatt t'iir Bakteriolooie. etc, XXIX., p. 329. 4 Ibid., 1910. Rd. LIIL, p. 256. 5 Journal of Infectious Diseases, 1909, Vol. YI., p. 203. CHAPTER V. ^ HABITATIONS, SCHOOLS, ETC. Section 1. GENERAL CONSIDERATIONS. It is essential to health that the houses in which we dwell shall be built upon proper sites, free from dampness and organic pollution ; they should be provided with adequate means for heating, ventilating, and lighting ; they should be well supplied Avith water for general domestic purposes, and provided with a proper system of plumbing for the removal of sewage ; they should be constructed with proper precautions against dampness from without or below. Heating, venti- lation, lighting, and plumbing are considered below under their several headings. Aspect. — It is commonly directed that habitations should be placed so as to face the south ; but, unfortunately, one is not always in a posi- tion to be over-particular in the matter of points of the compass, and, indeed, there seems to be no particularly good reason why that side of the house in which is located the main entrance should face south and the others respectively north, east, and west. The southerly side of a hill is very much to be preferred to the northerly, because of the greater amount of sunlight and of protection against the cold winds from the north ; but in a plain and elscAvhere, whichever wall of the house faces south, there must be, if the structure be rectangular, one to the north. Far better is a location with the corners of the house pointing north and south, for in that case every window must receive some direct sunlight at some part of the day, whereas with sides facing directly north and south, the windows of the former receive no direct sunlight and the rooms are dull and cheerless. In large cities, aspect is commonly a minor consideration, the desirability of a house being determined mainly by other circumstances. In general, it may be said that, when possible, a house should be so situated as to insure an abundance of light and air with protection against the cold winds of winter. Construction and Arrangement. — Consideration of building ma- terials and the details of arrangement of rooms and division of floor- space are beyond the scope of a work of this nature, and it is necessary only to call attention to the importance of insuring dryness, light, and air, and such thoroughness of construction as shall not permit a too generous amount of natural ventilation with consequent waste of heat. Of the very greatest importance is the character of the cellar, that part of the house which is most neglected during both construction and occupancy. Unless the site is one of unusual dryness, the cellar floor 470 SCHOOLS. 471 hIioiiIcI consisl. of :i ^ciicroiis hiycr of (•cniciil iinpervioiIK U) moiHture iVoin Ixilow ;i,ii(l to sri, yiicli an ^,'Ih from l(!!i,lviii^^ niaiiis. Tlic (oiiiidiilJoi) wmJIh .-IimiiM l>r li;.'li( and ly ol' li;^lit. Tlio vvuIIh Hlionid l)c Miado as fiir us poHsiblc pioof aj^ain.st wind and wcailKir. In C'\|)osi'o|)cr slope (iowiiu.'ird of fVom l<'ii If) tweiity (lc(i;i'('(!S, iind ils cdfrc should projccf, sli<.dilly over the for\v;ird (•A\rt'. {){' {\\v. cJinir, so lli;i,l llic hody ;iiid hciid iii;iy iiol lie iiM'liiin how lUH'.essary it is to life tliat llie C.'fX ^iven off bv the blood in the lnnt>;s to tlie inspired air shall be disehar^(;d eontinu- ously from the body, and we know that whatever other effects the im- purities of vitiated air may produce, the effect of undue COj in the air is to interfere with the function of res])iration. Therefore, it follows that the air which we breathe should be as free as possible from the impurities which we continually discharixe into it, and that this condi- tion can be obtained only by constant dilution of them by a constant supply of fresh air. In the open air, this dilution i^ties on without artificial assistance and requires no consideration ; but in confined spaces, Ave have to a certain extent a reproduction of the conditions that obtain in the lung ; namely, the presence of a volume of vitiated air, separated from the purer surrounding air, and requiring to be dis- charged and replaced. In other words, the air in the first confined space, the lung, is discharged into the second confined space, the room, and thence niust be removed to the outside and replaced by an equal amount of normal air. The constant dilution and removal of impuri- ties due to the necessities of life, so that their amount shall be so small as to be harmless, are the function of ventilation, which may be re- garded as the respiration of a building. It is, of course, not to be expected that the air of an inhabited room can under the usual conditions be maintained in a state of purity like that of the outdoor air, even though but one candle or one person he present to exchange carbon dioxide and water for oxygen, but the impurities can be reduced to a mininuun by the introduction of a ]iro]x?r amount of fresh air. AMiat shall be considered a proper amount of continuous air supply depends upon what we adopt as a limit of per- missible impurity, measured by the amount of CO., present. 474 HABITATIONS, SCHOOLS, ETC. For the maintenance of a fair degree of vigor and stability through proper oxidation of the blood and dilution of the effete matters dis- charged, and for the maintenance of the fullest and most perfect func- tional activity, one requires respectively about 30 and 50 cubic feet of air per minute. Less than 30 will inevitably produce impaired vitality ; more than 50 can be productive of no gain in improvement, so far as the effects of the ordinary vitiating matters are concerned. At the latter rate, then, an hourly supply of 3,000 cubic feet is necessary for the proper dilution of the respired air of each individual present in a conhned ypace. Thus, a room of 3,000 cubic feet capacity, inhabited by one person, should receive its full capacity of fresh air once every hour. But this renewal should be a continuous process, so as to prevent the accumulation of impurities which would occur if the air were replaced simply in bulk by an hourly aeration by opening win- dows for the requisite few minutes. Nor should it be supposed that even with constant fresh supply the air of the room can have the same composition as that which enters from without, for the impurities of each respiration are not removed in separate, distinct lots, but are mingled in the general bulk. If the occupant's head were in a conduit bringing the constant sujDply of fresh air and carrying away the products of respiration, no such amount of air M'ould be necessary, and no contamination of the general supply would occur. Under ordinary circumstances, Mitli an hourly supply of 3,000 cubic feet per capita, the amount of COj will not range above 6 or 7 volumes in 10,000, and any system of ventilation that will keep it down to this may be called good. Other imparities than those of respiration are to be considered in all questions of ventilation. The influence of burning illuminating mate- rial on the composition of air is very great, both as to the consumption of oxygen and the production of COg and other impurities, and it is not insignificant in its relation to the temperature. The impurities from 1 cubic foot of ordinary illuminating gas are such in amount as to require, according to various estimates, from 500 to 1,800 cubic feet of air for their proper dilution. They include not only carbon dioxide and water, but carbon monoxide, sulphur acids, nitrogen acids, marsh gas, ammonia compounds, unconsumed carbon, and other matters. Different forms of burners consume different amounts of gas to pro- duce the same illumination ; ordinarily from 3 to 6 cubic feet are used per hour, requiring 1,500 to 10,000 cubic feet of air-supply for proper dilution of the impurities produced by each burner. Therefore, on both hygienic and economic grounds, the burner which produces the maximum of light from the minimum of gas is the best for use, it being understood that a given volume of gas will yield the same amount of impurities, whatever the burner employed. The impurities from candles and lamps are less in number and variety, but, measured by their comparative illuminating power, they are larger in amount than from gas. For example, the combustion of AMOUNT OF SPACE RKQVIIiKl) FOli COOl) VENTILATION. 475 an aniouiit of ciiiidlc or kerosene oil neee.ss.'iry to jirodiifK; the Hame in<(!nHiiv <>(' li<:;lit, Jis 1 (;nl)ie loot, o(" |4;;is will [trodiiee IVoin 40 to HJO |)(!r eeni. more iinpurilic^H, iiiiliie(3 that which huH bect^me vitiaUjd by wh:US. 477 li(nii(>e through flues, through cracks around windows and doors, between the boards of the floors and of the general structure, and even through the interstices of unpainted plastering and UKH'tar, and through the jx^res of bricks. That a large volume of air will pass through cracks, needs no demonstration ; the passage of air through bricks, plaster, and mor- 478 HABITATIONS, SCHOOLS, ETC tar may easily be shown. If to the opposite sides of a brick, we fasten by means of sealing wax two ordinarj'^ glass funnels, and then smear its entire exposed surface with a liberal coating of the same material, all of the external pores excepting those within the spaces covered by the funnels are made impervious to air. If now Ave connect by means of a rubber tube the funnel on one side with a bottle in which air can be compressed by means of water pressure, and by the same means the Fig. 42. V Apparatus for demonstrating the permeability of bricks, etc., to air. other funnel with an inverted test-tube filled with water, and apply pressure, the passage of air through the pores of the brick will be manifested in a few minutes by the escape of bubbles from the outlet tube upward through the water. (See Fig. 42.) The passage of air through plastered walls is much impeded by wall paper, and may be totally prevented by oil paint and moisture. Numerous experiments have proved that with varying differences between the internal and external temperatures, the air of a room or building will be renewed partly, wholly, or repeatedly every hour, even when efforts are made to prevent as far as possible the entrance of the outside air. The results vary with the difference in conditions, the highest effects being produced when the temperature differences are wide, the opportunities for leakage great, and the external air in NA TIJllA /. FOnC.KH IN VF.STII,A TION. 179 active rnotion. Willi \)vy{\'ri c'llni ;inil ciiii.-il tcnijicradir*', llic rc-iilt will l)(! vil. Perflation and Aspiration. — liic(|ii;illil<- in (.ni-idc t(iii|.(ni(iir<« give ri.sc to the larger ciirrdiits of air wliicli we know as \viiir(iccc(ls IVoiii the o|)ci;i( ion of" ii;itiir:il f'orftij.s is known iis " niiiiiiiil \(iil Ihl ion." I'or (Ik; alt;iiiiiii< iit of iIh- lar^cht roHulls, f.li(!S(! lorcrs mil I hr uHsiHtcid to tlic; (!x(<'nl of niiioviil of ol>- stac-KiS lo llicir adioii >o far as may l)c advisahlc II is no( well to (Icjx'iid (i|)oii liic cliaiirc ci-acks and n|»(»n tin; nii;j;ialion of air thron^^li ilic |>oi'cs of laiildint;' nialcrials, hnl nccrssaiy opdnin^H, bo(li iidcts and ontlcls, slionld Ix^ |)fovidcd. 'I'lic nir.iici- tJic ((h.staflcs to (he cscaiK' of li('at(^e illustralxid I))' an licrmclicallv scalc(| niclallic Lox or by a closed ^hiHS bottle. Snpposc we proxldc one small opcniiiu' in the side of" tlie l>ox or in the stopper of the hotth; to act as an onllet and inlet, and ol).-er\(; the resnit. Aceordino; as tlu! eonlained air is warmed or (tooled, the openinji:; will act as an onllet or as an inlet, hnt only to a ]imit; of sonu; of the outer air; but in either ease, the movenu'iit is all one way, and there is no real interchange. .Su[)pose, however, two openings are supplied ; then one may act as an outlet, the other as an inlet, and a constant inward and outward current may be main- tained. The more tightly fitting we make our windows and dr)ors, and the more impervious to air we make our walls by means of paint and sheathing paper, the more do we oppose natural ventilation. On the other hand, the intelligent ])lacing of inlets and outlets furthers the object to be achieved. In addition to permanently installed inlet and outlet flues, temjio- rary openings may be ntilized whenever desirable. The most avail- able of these is the opened window, which may be utilized so as to avoid too voluminous exchange and unbearable draughts. The area of the opening may be very simply regulated, and the air may be deflected upward or the current may be broken up liv the interposition of fine wire gauze, flannel, or other pervious material. A very common plan is to place a board lengthwise under the lower sash, so as to fill completely the opening made by raising the window, and thus establish an inlet or outlet where the sashes overlaji each other, for the barrier to the movement of air, formed by the juxtaposi- tion of the lower border of the up]5er sash and the upper border of the lower one, no longer exists, and the entering current, moreover, is given an upward direction. Instead of a board, a frame, over which a diaphragm of flannel is fastened, may be used. This arrangement is pervious to air but impervious to dirt, which, therefore, is filtered out. Movable panes, either sliding or swinging by the side or end, are frequently employed, especially in double windows. There are also numerous patented devices for window ventilation, all designed with the idea of dividing or deflecting the current of admitted air. 31 482 HABITATIOSS, SCHOOLS, ETC. As has been remarked above, the most important force in natural ventilation is that dependent upon unequal temperatures of bodies of air ; in a perfect calm and with equal temperatures, natural ventilation would have to depend wholly on the force of diflPusion. The enormous influence exerted by the heating and lighting of a building or room on its ventilatiou becomes, then, self-evident, but it is not simply as a motive force that the relation between heat and ven- tilation is so close and important, for the incoming air must be raised to an agreeable temperature in order that the space may be habitable. Thus, a very large share of the cost of heating is chargeable to venti- lation, whatever the system of ventilation be. In the matter of expense, the amount of leakage through cracks and other small open- ings is, in a certain class of cases, of very great importance. In our dwellings, it is important that the interchaiage of air shall proceed continuously in the inhabited parts, but in buildings which are used only by day, and perhaps for only a few hours daily (schools, etc.), it is not essential that the air shall be renewed constantly at other times ; and here it is wise to obstruct the leakage as much as possible by perfect construction and by dampers in the flues, so that waste of heat, fuel, and money may be prevented. For the promotion of the process of natural ventilation, a number of " systems " have been devised, many of which can be productive of no results other than incomes for their promoters. As a rule, most of those noticed in works of this character are either ill-adapted to the conditions of our climate or incompatible with our methods of building, and will, therefore, not be considered here. The only system of natural ventilation worthy of advocacy is that which provides proper inlets and outlets and a suitable means of heating. Inlets and Outlets. — As to the size, location, and number of in- lets and outlets, no hard-and-fast rules can be applied for all cases, since the conditions are widely varying, and many different circum- stances have to be taken into account. But general rules may be laid down. If several inlets are to be provided in a room, it is essential that they should be distributed in such a manner as to insure a thorough blending of the admitted air. They should not be so placed, with reference to outlets, as to favor the forming of direct currents between them, Avhereby a large proportion of the inflowing air is discharged without having fulfilled its function — a not unusual condition, which illustrates that the amount of air admitted is not by any means a measure of thoroughness of ventilation. Their location is not such an important matter as the placing of the outlets, but, in general, an inlet is placed best on an inner wall where it shall be most nearly central in relation to the outside walls. With reference to the floor, if the incoming air is heated, inlets may be placed high or low ; but if it is admitted cold, they should be at a higher level than the heads of the occupants, and provided NA TIJUA L VKS'Tll.A TION. 483 widi .'irran^onKiiiiH f'or defied in;^ the emrenl townrd the fxtilirij^. Tliis may he .'iceoiiiplislied l>y caiisiii};; tlie <;iiiT«-iit, to impinge n|)r)ri a, siirCace slaiiliii;;' ii[)\vair, their natural trend is across that surface toward the inner warmer walls, where they become heated and arc inclined toward the ceiling, reaching which, they are pnslKsd by the force behind and drawn by the one in front toward the outer walls and windows again. In the meantime, some of the air is escaping through outlets, and diffusion of the impurities is proceeding, so that a more or less even character is brought about throughout the air of the room. Outlets may be placed at the level of the floor, in the ceiling, or at any height in the walls, according to the conditions of each individual case. If the incon)iug air is not heated, the outlets should be placed high up, for where only unheated air is admitted, the warmest air must be the oldest and its location w ill be in the upper air space. If, on the other hand, the air is heated, the outlets may be anywhere so far as height is concerned, but there is some choice in locations with respect to inner and outer walls. Outlets placed beneath windows or near outer walls M'ill withdraw the falling currents of the only recently in- troduced air before it has had an opportunity to become well mixed by passage across the floor to the other side, and before it has in any propei degree fulfilled its functions ; but if its passage through the loAver strata is not interrupted in this manner, it is enabled to mix with and dilute the impurities of the air already vitiated, and thus effect a large measure of work, and so when it reaches the other (inner) side and finds an outlet for its escape, there is no objection to its withdrawal, and, indeed, its removal then is highly desirable. Hence, and for another reason as will appear, outlets should be placed in inner walls rather than near or in outer cooler ones, and near the floor where they may intercept the air before it may again become a part of the ceiling currents. If but one outlet is to be provided, it should be placed with reference to the most even movement of the current over the whole area, having in mind the fact that the air movement toward it is convergent, and the direct reverse of the flow from the deflecting and diffusing surface at the inlet. As to size, it may be said, in general, that a single outlet, or the 4.'=(4 HABITATIONS, SCHOOLS, ETC. aggregate if there be more than one, should be of such size as to insure tlio p().>^sihi]ity of removal of such an hourly air supply as the space is likely to require under the ordinary conditions of its usual occupancy ; that it should not materially exceed this limit; and that the final velocity of the ontriowing current should not be productive of the sensation of disagreeable draughtiness. As to the shape of inlets and outlets, it is self-evident that, with equal arejis, that which has the smallest periphery Mill offer the least frictioual resistance, and is, therefore, best adapted. Thus, a circle en- closing an area equal to a square foot has a smaller periphery than a square enclosing the same area, and a square has a smaller one than an oblong rectangle. Take, for instance, a square foot ; it may be in- cluded Avithin boundaries : 12 X 12 indies, a square. 16 X 18 X 8 24 X 6 36 X 4 ■ oblong rectangles. 48 X 3 72 X 2 144 X 1 . With these boundaries, the periphery ranges from 4 feet (the smallest) to 24 feet 2 inches. The frictioual resistance will, therefore, be greater in proportion as the shape varies from the circle and square. The shafts communicating with the inlets and outlets should l)e so disposed in the general plan as to offer the least resistance to the inflow and outflow of air. Unless they are heated artificially, inlet flues should not be located in outer walls, on account of the likelihood of the formation of down draughts due to cooling of the air column. Their inner surface should be as smooth as possible, in order to bring to a minimum the loss of movement due to friction, and they should be cylindrical, if possible, for the same reason. They should be as free as possible from angles, and especially right angles, because of the very serious loss of motion which these cause, each right angle dimin- ishing the current about half; thus, after passing one right angle, the flow would be half; after a second angle, the half would be reduced to a quarter, and after a third, to an eighth. The neglect to take into account the loss of flow by friction, l^ends, and angles is responsible for the failure of many a plan for ventilation. What has been said concerning the impossibility of making general rules for the sizes of inlets and outlets applies with equal force to the fixing of sizes of flues, for these depend upon the many and varied conditions which, even under the best favoring circumstances, affect the rate of flow. In planning inlet and outlet shafts, it is to be borne in mind that something more is necessary for their proper -working than the dictum that this one is for fresh air and that one for foul, for natural forces have no respect for mere names and plans, and the current in a flue will be upward or downward, inward or outward according to natural A]t'ril''l('r.\L IIKATINd IN ITS llh'.LA'riOSS TO V I'.Sri I.ATIOS. IH/i hivvH. ()ii(l(l sliid'tH may bcronir- coiisidcmhly roolcd hy low (;xt4!rna) (cin|)('r;iliii'('s ; (JK^y iiwiy I)'' iii\;i(|iil In' r;iiii ;iii(| snow, tlic cvaporafion of wliicli cniiscs cooling' ;iiicliani('al v(!ntilatioii consists in flic ))ro|)ulsion or (;xtraftion (tfair by means of blowers or cxhanst fans dri\(Mi by Htorly. Tlicy an; cHtal)- lislied l>y tli(! wa,rnier walls, floor, fnrnilnre, liot-wat<;r ))i|H!H, Hli-arn radiators, close! sloves, and odier warm objects, and in this way tlic air b(!C()meH li(!a-t(!d. The air wliieli enters rooms tliroii^li KbaCts com- mnnicaiint^ with tlu! air ehanibersoC ('nrna\. W.) slli<',(! l.lic |)(:r("c('t, coiiihiisl inn ol" ^(kkI oil ic-iilt- in (••■iilioii (liox idc ari'l water; htil. willi ^;i,s (Jic ixodiK^ls \i\v. more ininn roiis jind varied, ;uil,-air Cnrnaccs aic iml only oC \cry (.ri-i a( iiii j»or1arif<; us li(!ai(;rs, l)iili <>(' cnornioiis inflncncc in \(iil ilal ion. In llicir use, tlio cold outdoor air is hrona.iil In liy ;i condnit, (lu' "cold-air l»o,\," to a cliiunlKT in [\\v. upper \y.\v\ of I lie rnrnaee, altove ;iud surroundiuj^ tlic "doUH!," where it <'o!nes in eoiila<'t with the very hot Hurf'acc and is hciited by coDvee.tioii. 'riieiiei! it, passes u|)\vaid through sf'f)!ir:iti':'ri':i!.!\iiN.\'i'i()iS of n.\'ri:s of vFS'rii..\'rio.\. \'x\ |)C(;ii lic;ii-(Mi wllli somr (lillii'nl I \ , ;iic nnw iii;ii|c hhmc coinC'irhililc, ;iiii| in l,li(! vvliolf^ Ijiiildiiii;- ."1 flc^^rccs l(!.srt lic;il, arc r< (piircd ('<»i- (li<- iii.iiiiicn- jiiic.(! ()(' iiii :ii;;i(<';il)lc (ciniMTaliH'c. A(H!(»rl;iiil VVUH ilistiillcd, " am. titer fcatiin; iii(li(ratiii^ IIk! j^icater cuiiilort of llie Idiildin^ was llu; al>.-^<-iie«; in win- icr of (Jic, conti'liin^' hy (li(».S(; cniiiloyc*! llicrc, ;i con^li of" tlio l)rone|iial kind oi' IVdUi IIk; laiynx, a, (toiieh wliieli ends willi a h(|neal, wliieh is so |)r(ivalen(, in N;(! vohniies of air int rodncred into a hnihlinj^ for purposes of \-eiililalion. In the hnihlini^ above mentioned, the air is drawn into and tln-on^li a system ol" large (cotton bag-s .'iO feet in length, in which all dirl and dust is retaiiictd. About a peck per month is separat(' estimation of the amount of air entering and leaving a room through inlet and outlet flues is a very simple matter, but the results may not be accepted as an indication of the efficiency of ventilation, since it so often happens that much of the efllucTit air has failed to per- form its full duty in diluting the im])urities arising from respiration and combustion. Nevertheless, such a determination may yield im- portant indications. In order to ascertain the volume of air passing through an opening, whether inlet or outlet, it is necessary to knoAV the area of the opening and the velocity of the current. The former is easily ciilciilated arith- metically ; the latter can be found only by the use of an anemometer, an instrument of very delicate constrnction, which registers tlie distance travelled by a current of air in any period during which it is ex- posed. A current of air, passing through an oi^ening, has not the same velocity at all points of its cross-section. It moves in the same manner as a river — faster at its center, where it is least subject to the influence of friction. Therefore, the velocity should be taken at different pevints, and the mean of the results accejited as its true rate of movement. The anemometer is held for a given time, say half a minute, at a ]x>iut at the periphery of the opening, and then moved along a short distance and held for an equal period, and so on, from point to point, until the whole area has fairly been traversed. The reading of the instniment is then noted, and the distance iudicatal is divided by the number of ^ Trausu'tioiis of the Now England Col ton Manntaotiu-ers' Associatiou, Vol. 63. 494 HABITATIONS, SCHOOLS, ETC. points where stops have been made. The quotient equals the distance travelled by the whole current during the unit of time employed. It will be found most connuonly that the movement at the periphery is very slow, and that, as the center is approached, the velocity becomes greater and greater, the maximum being attained at the center. Know- ing the average movement in feet or meters, the volume is calculated by multiplying this by the area in square feet or square meters, the product being the volume in cubic feet or cubic meters passing during the unit of time. From this result, the volume per hour is easily made known. Example. — The size of the opening is 2 by 3 feet ; the area is, therefore, 6 square feet. The anemometer, held at twenty-four points for fifteen seconds each, registers 228 feet. The mean of this is 9.5 feet, and the current is moving, therefore, at the rate of 38 feet per minute. The cross-section of the current being 6 square feet, the volume discharged in a minute equals 6 X 38, or 228 cubic feet, and, in an hour, 13,680 cubic feet. By determining the rate of discharge through all inlets and outlets in this manner, an idea is obtained of the amount of ventilation occur- ring through means provided, but, as has been stated, not of its effi- ciency. The sum of the inlet discharge will almost never agree with that of the outlet, since much air enters and leaves a room through other openmgs. Knowing the capacity of the room, we learn from the amount of inlet air the number of times the air of the room has been replaced. The full measure of ventilation and its efficiency may be determined very closely by methods originated by Pettenkofer. One of these con- sists in first creating an unusual degree of impurity either through respiration of a large number of persons, as, for instance, by children occupying a schoolroom, or by burning a number of candles, or by other chemical processes, then, after taking a specimen of the air for analysis, keeping the room closed for an hour or two. At the expira- tion of the allotted time, a second sample is taken, and from the results of the two analyses, the rate of ventilation is ascertained by means of Seidel's formula, which is as follows : C =-- 2.303 m. log ^i^^- in wliicli C = amount of air which has entered. 2.303 is a constant. m = capacity of the room. Pi = amount of COj originally present. P2 = amount of COj at the end of the experiment. a = amount of CO.^ in the external air. Example. — The air of a schoolroom of 500 cubic meters capacity, accommodating 34 children, contains at the end of the session 18.5 cc. of CO2 in 10,000, or 0.00185 : 1. At the end of an hour, a second analysis shows 8.5 cc. of CO, in 10,000, or 0.00085 : 1. The outer air contains 3.5 cc. of CO, in 10,000, or 0.00035 ; 1, 11l(^ LIGHTINO. 105 = 1161.5 X '"K , - = 115]/) X !')«"' = 1151/) X 0.4771 ii I.". — A'lK.l ciihic ir)cl(TM of ;iir in ;iii lioiir. Tlius, the Jiir of ilu; room is n^ncwcd but once, and Ji U-iitli per }iour, and the result .shows that tlie per capita ventilation is about a fifth of what it should be. Tlu! other nicdiod (^ousisls iii iinj)arting to the air of a room a eoiitiii- uous sup|)ly of" (larbou dioxide; by means of burning eandh'S, and making periodieal analyses of the eontained air. Candles of pure sU^arin, 1 gram of whieh yields 1.404 liters of the gas, are employed. A prelimi- nary analysis of the air is mad(;, and then a mnnb(!r of the eandles, the combined weij^ht of whieh is noted, are })laeed about the room and lighted. At stated intervals, the room is. entered, and after the air has been well mixed by vigorous fanning, samples are taken for anal- ysis. At the end of the experiment, the candles are put out and re- weighed, and from their loss in weight and the results of the analyses, the amount of ventilation is calculated by means of a most complicated formula devised by Ilagenbach. Other methods have been proposed by Recknagel, Petri, and others, but they present no advantages, and are, in general, so cotn plicated that in the hands of other than expert physicists they are quite useless. Section 3. LIGHTING. Natural Lighting. — In natural lighting, the light enters the room directly or by reflection through the windows, and is then reflected to different parts of the interior, which receive different amounts of light according to circumstances. Thus, white and light-colored walls, floors, and articles of furniture reflect and disperse the light, while dark walls, draperies, and other objects absorb it. Large rooms having but small window area and all rooms, however generously provided therewith, looking on narrow alleys or streets in which the opposite buildings are so high that the sky-angle is small, cannot be illuminated uniformly by diffused daylight without some assistance. The means employed are exceedingly simple, and the disco verv of their utility for this purpose was due to chance. In order to obstruct the view into factory workrooms from the outside, and to lessen the temptation to operatives to waste time in looking out, ribbed glass was introduced instead of ordinary glass for use in windows, and it was noticed that not only was the desired end attained, but that the light from the windows was projected farther into the rooms, and to such an extent in some instances, that artificial lights, required before in the brightest part of the day, could be dispensed with. Attention being thus drawn to the great advantage and saving of expense, a num- 496 HABITATIONS, SCHOOLS, ETC. ber of different kinds of glass with uneven surface have been placed upon tln' market and haw come into very extensive use. The best of these, which is the most expensive, is known as " i)rismatic glass " from the fact that one surface consists of a series' of prisms running horizon- tally. The entering light, instead of falling directly to the floor, is FiQ. 49. Fig. 50. Action of prismatic glass in projecting light. tipped up and projected toward the opposite sides of the room, as shown in Fig. 49. Vertical section of a sheet of the glass is shown at A in Fig. 50. By varying the angle of the prisms, the conditions obtaining in any situation can be met and light may be projected in any desired direc- tion. Naturally, the prisms cannot be used indis- criminately, for a series adapted to light the entire lower part of the room with a certain sky angle might, when applied to another, throw the light toward the ceiling instead of to the parts where it is required. Therefore, to meet all conditions, the glass is made with a great range of angles, and the particular kind needed in any situation is determined by measurement. Where the sky angle is very small, canopies, hung at the proper angle above the windoAvs, serve to throw inward a flood of light. The disadvantage of prismatic glass is its great cost. nibbed glass is very efficient and much less expensive. This is made with 4, 5, 7, 11, and 12 ribs to the inch, and of different thickness and weight, since the fewer the ribs, the deeper they must be cut, and the thicker, therefore, the Vertical section of pris matic and ribbed glass. ^l;i-ss. V(!rli(',;il section dC ;i sliccl oC lildicd j/l.-iss \h hIiowii .'it // in Vu^. 50. Artificial Lig-hting.— 'riic ni<'llionie ixU-iit, ;dlhoii^^h not, very much in this eonntiy. Il;ird f;its in the I'oini (»!" (;;iii;ives out practit^dly no li,L;ht ; \\\r middle portion, dark in color, consists of hy(b'ocai"l)on t;as (generated from the substance of the (^andl(!; next is the luminous yellow portion ; anarticles of carbon in the l)i"(ndving up of the hydrocarbon compoinids into their elements. A mixture of gas and air, such as occurs in the use of the Bunsen burner, gives off little or no light, since each particle of carbon is provided Avith sufficient oxygen to convert it at once into carbon dioxide, and so incandescence cannot occur. If the air supply to the interior of the flame is shut off, huninosity is produced at once. If the area of the outer surface of an ordinaiy gas flame is so small that atmosj)heric oxygen cannot be taken up sufficiently fast to unite with all the carbon arriving at the outer part of the flame, the unoxi- dized carbon becomes cooled below the ignition point and is given oft' in the form of smoke. Defects in the bnrner or excessive richness in hydrocarbons may cause smoking during combustion, the supply of air being too sniall to consume the carbon. The introduction of a cortion of the flame causes deposition of soot thereon. If the area of the flame is made too large by turning on a large volume of gas imder high pressure, the gas is projected so far that it comes in contact with sufficient atmospheric oxygen to burn a large part of its carbon and hydrogen simultaneously, and, as a result, the excess of gas is consumed without luminosity and wasted. 32 498 HABITATIONS, SCHOOLS, ETC. Gas Burners. — The best of the burners in most common use is known as the /xifs-iring, from the shape of the flame. The tip is hemispher- ical, and is provided Avith a single straight slit, through which the gas emerges in a thin flat sheet. Another, known as the Ji.sh-tail, contains in its tip two small orifices, through which the gas issues and then spreads out into a flat flame, shajied as the name indicates. This burner is inferior to the bat's-wing in that its flame is less luminous with tlie same amount of gas, and the orifices are much more easily fouled and occluded. The Argand burner consists of a hollow ring, provided with a circle of small holes and attached by hollow arms, through which the gas is supplied, to a socket screwed to the pipe. The gas, issuing from the holes, forms a circular flame, which is provided with an abundant air supply which passes upward through the perforations of the holder for the chimney, which is an essential part of the apparatus, and through the central hole of the burner as Avell. The chimney should be of proper diameter and height to insure an air supply adequate for com- plete combustion of the gas. The Wekbach burner, which may be taken as a good representative of the class of incandescent lamps, consists of a modified Bunsen burner, over which is suspended a mantle composed of incombustible material, which becomes intensely luminous when heated in the Bunsen flame, and thus transforms non-luminous heat energy into luminous light radiation. The mantles are made in different ways, of different mate- rials, and are exceedingly fragile. One of the most common and best sorts is made by saturating a delicate network of cotton in a strong solution of several earthy oxides (cerium, zirconium, lanthanum, thorium), then baking, and finally heating it until the cotton fibers are destroyed, thus leaving a gauze composed of the oxides alone. No single earth is effi- cient by itself. The flame and mantle are protected by a cylindrical glass chimney, which serves also to steady the flame, and the whole is enclosed commonly in some form of globe or shade to modify the intensity of the light. By providing a suitable burner to insure the requisite degree of heat, any kind of combustible gas or oil vapor may be used. Lamps are made on the same principle for kerosene burning. The incandescent mantle not only gives out much more light than an ordinary or Argand flame, but does so at a much smaller expenditure of gas. Objection is often made that the Welsbach light is very trying to the eyes. This is true ; but the same objection may be urged against the sun and other intensely bright objects when looked at directly. The lights should be so placed that they will illuminate those parts where light is needed ; and if they are likely to try the eyes, they should be enclosed in globes designed to soften the glare and diffuse the rays uniformly. VABrETflCS OF ll.l.llMfSATINa (J AS. I-'O Varieties of Illuminating Gas. Coal-gas i.s iii;mI(' Uy lic;iliii^; Wilniniiioii- roiil in lii-c-clny retorts, in whi(!l> |)i-()(!(!HH lJi(! coimiioiiik's oI' liy() parts of liydrof^en, 35 of marsh-^as, (I or 7 of (iarhoii monoxide, and llie remaiiidt-r of ethylene and other hych'ociarhon.s, and nitrogen. Water-gas is made from coke or unthracito (;(vd, .stt^am, and petroleum. The coU(! or coal is placed in an air-ti^ht cylinder lined with fire clay, and tluMi is in;nitcd and blown np to a white heat by ni(!an.s of a bla.st of air. The air is tluui shnt olF and a current of .steam is blown throuo;!). Tiiis is decomposed by the great heat into hydrogen and oxygen, the former ]>a.ssing on uncombined, and the latter uniting with carbon to form carbon monoxide. The resulting mixture is then car- ried to a gas-holder, from which it is conducteosure. In recovery from poisoning, the carbon monoxide is not oxidized in the body, but is driven out of its combination by the oxygen of the in- spired air ; but although after a few hours the blood may nearly be freed from the poison, the damage already done to the brain and other tissues 500 HABn'ATIOyS, SCHOOLS, ETC. through the temporary partial ilejirivation of oxygen may be severe ancj lasting. Recovery is aecompanit'd commonly by severe headache, persisting for a long time, often with nausea and vomiting. The increased danger of gas-poisoning when coal-gas is supplanted by water-giis with its high ciirbon monoxide content is well shown by the statistics bearing on the subject at Boston, jNIassachusetts. In 1888, when but 1 per cent, of the gas sold was water-gas, there were no deiiths, suicidal or accidental, from gas-poisoning. In the following year, there was but 1. In 1890, the percentage of water-gas rose to 8, and there M'ere 6 deaths, 4 accidental and 2 suicidal. In 1892, as a result of permissive legislation, 52 per cent, of the gas sold was water-gas, and the deaths rose to 15. In 1897, the percentage rose to 93, and the deaths to 47, 32 of which were accidental and 15 suicidal. In the five years ended September 1, 1899, 169 deaths had occurred. On account of the danger, a commission appointed in England in 1899, reported adversely on all illuminating gas containing more than 20 per cent, of carbon monoxide, which proportion corresponds approxi- mately to a mixture of equal volumes of coal-gas and water-gas. Acetylene gas, C2II2, is an unstable compound of carbon and hydro- gen. It has a strong, disagreeable odor. Mixed with air in the pro- portion of 1 to 19, it is violently explosive. It is poisonous, but not to the same extent as ordinary coal-gas ; an animal exposed to an atmosphere containing it becomes unconscious after a time, with no manifestations of nervous or respiratory excitement, and, if removed at once, recovers in a very short time. Prolonged exposure is fatal Blood will absorb about 0.8 per cent, of its volume of acetylene, but the solution gives no characteristic spectroscopic appearance. If any compound is formed with haemoglobin, it must be very unstable. If a high percentage of oxygen be present, animals may survive its action many hours. Acetylene is made from calcium carbide, a reddish-brown or gray material prepared by subjecting a mixture of lime and coke to very intense heat. When this substance is wet with water, a double decom- position occurs, the calcium uniting with the oxygen of the water to form quicldime, and the carbon Math the hydrogen to form acetylene. Between four and five cubic feet of the gas are yielded by a pound of the ordinary commercial carbide. Burned in ordinary gas-burners, the flame cannot secure a sufficient supply of oxygen for the complete combustion of the carbon, and in consequence it smokes and fails to exert its full power of illumination. By using a tip with an exceedingly thin slit, and forcing the gas through under heavy pressure, the flame is greatly enlarged and is of great brilliancy. Its illuminating power is about 15 times greater than that of ordinary gas. Acetylene is liquefied at a temperature of 64° F. by a pressure of 1,200 pounds to the square inch, and may be stored in cylinders of steel. Apjjaratus for its use should not be made of copper or silver, VA/!.f /<:'!'/ h'S OF II.LinilSA'r[S(J (IAS. •''''''1 since thcHC nuitills arc ;iti;ickc(| hy il, ;iii(| I lie rc,-iil( iiij/ c .)ii|)()Iiii(1m iirc V('IT explosives III some ;i,|»|);ir;iiiiscs in use, I lie \\;it(i' is
  • in|)osilioii. In others, t be eaibide is iiilrodiie.()2i) to O.tKiT. It volatilizt'S slowly at low temperatures and ra|)idly at TO*^ l'\ and above. It is exceedingly intlammable. Gasolene gas is generated and f"orced through supply pipes to the burners by special forms of a[)paratus which re<|uire but little atten- tion. It is well suited to single houses and small groups of houses where no public supply exists. Impurities Given off in Lighting. — In the conil)ustion of illumi- nants of all kinds, considerable amounts of decomposition products are given oti' to the air, and their removal 1)y means of eflkient venti- lation is important. These ]n'oducts are least in amount and im])or- tance in lighting with candles and oil lamps, being chiefly carbon dioxide and watery vapor. The impurities given off in the combus- tion of gases include sulphur dioxide, very variable in amount accord- ing to the extent of juirilication ; carbon monoxide, also variable according to the completeness of combustion ; carbon dioxide ; ammo- nium compounds, and aqueous vapor. Gas Pipes. — Street mains are commonly made of cast-iron pipes of rather light weight, which vary much in texture and density, and not infreijuently are perforated with blow-holes of varying diameter or otherwise defective. On account of the dangers of extensive leakage and of the financial loss due to waste of gas and the cost of making repairs, all pipes should be tested thoroughly before being laid. Pipes which show no leaks when new may soon be corroded in the soil at points where bubbles occur in the walls with but a thin layer of metal on either side. A^ rought-iron pipes are corroded more quickly in the soil, but are more uniform in density and texture than cast-iron and require fewer joints in a given distance. Both kinds should be pro- tected by a generous coating of asphaltum or other suitable material. House pipes are nmst commonly of wrought iron, though sometimes softer materials are employed. The latter are more expensive, and 502 HABITATIONS, SCHOOLS, ETC. possess the additional disadvantage of being easily punctured by nails and gnawed by rats and mice. The entire system of distribut- ing pipes should be joined most carefully, in order that no leaks shall occur. A\ hen they do occur, the search for their location should be conducted "with all possible precautions against risk of explosions, since mixtures of gas and air in the proportion of about 8 per cent, of the former are violently explosive if brought in contact with a flame. The gas should be shut off at tlie meter, and the apartments Mdiere the smell is perceived should be aired thoroughly. The examination should then be begun at the meter and its connections, and if defects are there found, the meter, if at fault, should be removed, or the con- nections put in proper condition with new Avashers. The fixtures should next receive attention, every joint and cock being tested, the gas being turned on again at the meter. Smearing the joints with some viscid material, such as strong soapsuds, will show small leaks by formation of bubbles. The examination of the joints of the dis- tributing pipes is a matter of considerable difficulty, and may require much disturbance of structural parts. Fixtures should be so located as to avoid hot-air currents from reg- isters in the floor and walls, on account of the great annoyance caused by flickering of the flame. Flickering is caused also by the presence of condensed moisture in sags in the pipes and bends in the fixtures, which causes the gas to issue in a series of bubbles with consequent un- steadiness of the flame. The remedy consists in interposing drip cups and draining off the water. The proper arrangement of fixtures is frequently a difficult problem, particularly in large rooms. In general, it may be said that they should be well distributed rather than clustered in central chandeliers. Fairly uniform diffusion may be secured by the use of globes of pris- matic glass, which act in the same way as the ribbed and prismatic window glass described above. Electric Lighting". — Incandescent electric lighting possesses cer- tain notable advantages over all other systems of artificial illumina- tion. It requires no oxygen and produces no decomposition com- pounds, and hence in no way alters the composition of the air. It imparts but little heat to the surrounding air, and hence has but a limited influence in causing convection currents and raising room temperature. Section 4. PLUMBING. Whether we view the subject from the standpoint of possible danger of infection through inhalation of sewer air or from that of aesthetics, we should recognize the great importance of the removal of all sewer wastes from the habitation through a system of plumbing that is so perfect that it shall leak neither liquid nor solid matters, nor foul air and smells. For the attainment of the best results, all large commu- nities adopt plumbing ordinances designed to prevent faulty construc- tion and the admission of the dreaded " sewer gas," which, to the lay rijiMiiisa. -V)."** mind, iiiid Vi'vy ^(^mirally to tin; iJi-ofcsHiotiiil rnind ;is wj-II, Ih 51 moht p()t,li the inia,i;i nation, I, more partienhiily, Ihroiij^h their el!ect« on the a,|)|)etit(! and digestion. Most oC (he fonl Hinell.s connrif^ from |)hnnl)in
  • cvidcnl lliiit lli«- nature of tlic nmtcriul, tlio mkIIkkI oC operation, .inil the (!lianiet<'r of the ajjplied S(\WM}ji;(( have; very (Htiisiderabh- elleefs upon (he <|iialitv of" the eflhieritH from contiUit fiUcrs. The lih(!rs eomposed of eolart in the action of the filter. If the material is too coarse the voids are large, and the sewage does not come intimately in contact with the surfaces. If, on the other hand, the material is too fine, clogging occurs, and the action within the filter becomes largely that of mechanical straining ; moreover, j)utrefactive reactions abound, in- asmuch as the entrance of oxygen is largely precluded. . . . The question as to the proper dei)th of contact filters ajipears to be one of engiueering rather than of sanitary interest . . . and has xeTx little relation to its biological activity. The difference in depth, however, does make, a great difference in the volume of sewage which can be disposed of upon a given area. From this point of view deep beds are better than shallow ones. " The method of operating contact filters also has considerable effect upon the character of the effluent. . . . The question of how long the sewage should remain within the filter has not been determined abso- lutely. . . . Systematic resting of the filters for a period of one week in every six has proved to be beneficial in every case. . . . " The character of the applied sewage also plays an important part in the quality of the effluent. The best effluents and the best filter operation is secured when the applied sewage receives some preliminary treatment to remove suspended matters." Trickling Filters. — The fourth method of purifying sewage by the use of micro-organisms is purification by means of what are now known as trickling filters. These filters are an outgrowth of studies in regard 1 Massachusetts Suite Board of Health Report, 1908, p. 444. 652 DISPOSAL OF SEWAGE. to the bacterial purification of sewage made at the Lawrence Experi- ment Station during- the first three years of its operation. In June, 1889, a filter of gravel stones was started there, some of these stones being not less than throe-fourths of an inch in diameter nor more than one and one-quarter inches. To such a filter sewage was applied and good nitrification occurred. In summarizing the results of this filter, it was stated that " the purification of sewage by nitrification and the removal of bacteria is not to any essential degree a mechanical but a chemical cliange ; that the ex]>eriments with gravel stones give us the best illustration of the essential character of intermittent filtration of sewage, — the slow movement of the liquid in films over the surface of the stones with air in contact." Such filters were operated at Law- rence as early as 1890 at rates as high as 200,000 gallons per acre daily, and the sewage was applied frequently, often sixty to seventy doses a day being given. Dr. Dunbar, Director of the Hamburg (Germany) State Hygienic Institute, makes the following statements : *' Of much more general importance, however, are the experiments which have been carried out at the Experiment Station erected at Law- rence. By selecting the most suitable soil attempts were made to in- crease the efficiency of the method, and finally such coarse material was used that the sewage passed straight through without spreading over the filter. Automatic devices had to be adopted to distribute the sew- age. The London authorities became aware of these experiments and had them repeated. In 1892 Santo Crimp prepared experimental fil- ters of similar coarse material at Barking. ... It is not generally known that simultaneously and independent of Dibdiu, J. Corbett, the Borough Surveyor of Salford, worked out a biological method of puri- fication. His method was likewise based on the Massachusetts experi- ments, but in its further development it has surpassed the London methods. . . . Corbett attempted to apply the principle laid down by Sir R. Frankland and recognized to be correct by the Massachusetts authorities, viz., that an intermittent filtration liquid should always be allowed to fl.ow freely away. . . . The chief difficulty to be over- come was to obtain a uniform distribution of the sewage over the entire surface of the filter. After many experiments in various directions, Corbett adopted for this purpose fixed spray jets from which the sew- age was distributed under pressure in the form of a fountain." At the present time trickling filters are in use purifying sewage of a large number of English cities and towns, and at least three good puri- fication plants of this type are in operation in America, namely, Colum- bus, O., Reading, Pa., and Baltimore, Md. Such filters, both in Europe and America, are generally constructed of broken stone, although in many places abroad hard clinker is used. These filters are usually from five to ten feet in depth, and of material so coarse that the sewage passes through freely, the open space in the filtering material being so large that there is abundant and constant supply of air. By this method of filtration rates from three to four times as great as those possible MF/niODS Oh' SFAVAdl': DISPOSAL. 5rj.'i with c.ouUicA, filtcns can \n: tnuiiilaiiifd with the proihidion of a highly nitrilicd and noii-ittili-cscihh' dilhicnl. A(, liifmiii^diarn, lOii^laiid, ihcn; is ut tlie j)roH(!nl, (imc (he most ('xti.'iiHivo j)iirilif',;iti(»t) phint of this type. At this phiiit the .s(!\va^c ol' about H(K),()()0 people i- piirifierl jjy rneaiiK of septic tanks and trickling (illers. Two experinienlal lillcrs of this kind iiave been in operation at the Ijawrence Experiment tStatioii for about twelve years at averaj;r; rates ofmorethau 2,000,000 gaHons per acre daily, and are Ktill in gornl condition and j)racti(!ally i'ro.c. from clo^r^'injr. Jn order to rjbtain j^ood results from these fdtxM-s, fairly j)erfeel distribution of th(! sewage over them is necessary. 'I'Ik; spray jets first used by Corbett liave been adopted at many of the hirj^e j)lants of this tyj)e, but many other dis- tribution methods are used. Some of these distributors, such as the Fiddian and (lie Siini)lex, f^ive better distribution results than can be obtained with nozzles or jets of the (orbett and allied types, but jren- erallv are more expensive, especially for the first installations. The Fiddian distributor is constructed in the manner of an overshot wheel and is self-propelled. It is well adaj)ted for circular beds, such as are constructed at scores of ])laees in FiiLrhind and on the Continent, and with the use of certain automatic contrivances can be used upon rec- tan2:ular beds. "The main difference between trickling filters and intermittent sand filters is that, owing to the size of the open spaces between the particles of filtering material in the trickling filters, much greater rates can be maintained and still allow the free entrance of air. Trickling filters are not a substitute for sand filters, which remove practically all the matter in suspension in sewage, but are simply devices for the modifi- cation of sewage, or, in other words, the quick oxidation of the putre- fying matters present while allowing the larger body of stable matters and matters rendered stable by filtration to pass through. . . . The grade of filtering material used may be varied according to the charac- ter of the applied sewage ; that is, a finer material may be used with a supernatant sewage from sedimentation or chemical precijiitation than when the sewage contains much suspended matter. It follows, of course, that the finer the filtering material and the clearer the sewage the better the effluent, but too fine a material cannot be used, as sur- face ]>ooling ensues and air is excluded." ^ The type of filter to be erected at any locality is often determined by certain engineering limitations. Contact filters can be used at places where trickling filter installations are almost impossible. This is clearly described in the following paragraph : "Another distinct advantage of the contact bed under certain condi- tions is the low head under which it can be operated. A trickling filter requires at the least 8 feet of head for the bed itself and for the dis- tributing apparatus ; while a double contact bed could, if necessary, be crowded into 5 feet. Altogether a contact installation lends itself to compact and inconspicuous construction, which is of much practical 1 Clark aud Gage, Massachusetts State Boai-d of Health Report for 190S, p. 3S7. 554 DISPOSAL OF SEWAGE. importance in the design of small plants for institutions or for private houses. The contact bed produces less odor than the trickling lilter and does not breed liies as the trickling filter does. It may, therefore, safelv be installed much nearer to dwellings. Another advantage in the contact system for small disj)()sal plants lies in the tact that it adapts itself more readily to marked irregularities of flow than does the trick- ling bed. If,- however, plants of this type are designed to work under the control of automatic ajiparatus, it must be remembered that a lack of careful supervision will mean certain and inevitable failure." ^ The Cameron Septic Tank. — What is now known as the septic-tank process was first proposed by Donald Cameron, Borough Engineer of Exeter, England, where the first attempt at preliminary treatment of a town sewage by this system was installed. A septic tank is in a sense simply a cesspool on a large scale, but more scientifically operated than the ordinary cesspool. The process is one in which the anaerobic bacteria are utihzed for the purpose of hastening the decomposition of organic matter in sewage. By the process as proposed by Cameron, sewage is passed slowly through large tanks, so slowly that not only does organic matter in suspension settle out and remain in the tank, to be Avorked over by the bacteria of putrefaction, but the sewage itself when passing from the tank has also been submitted to the work of these bacteria for a considerable period of time. The initial plant at Exeter consisted of an underground covered tank, 64 feet long, 18 feet wide, and of an average depth of a little more than 7 feet. At this place the crude sewage before entering the tank passes first into a brick chamber, where the coarser and heavier matters settle out. The sewage is not strained, but passes to the septic tank proper after passing through the brick chamber, and enters the tank through inlets five feet below the surface. After this tank had been in operation for a period of a year or two, it was stated that 80 per cent, of the organic matter in suspension and retained in the tank was passed into solution or escaped in gaseous form, hence did not appear in the tank effluent. At the present time such tanks have been in operation upon a large scale for a number of years at many places in England and in America, and it is now the general opinion from the results of their operation that even under the best conditions they do not destroy more than 25 per cent, of the suspended organic matter retained by them. At certain large installations, as at Hanley, England, and at Birmingham, England, the destruction does not seem to be greater than 10 per cent. They are, however, undoubtedly of considerable value at certain places as adjuncts to sewage purification, and are well recognized as one of the prominent forms of preliminary treatment of sewage before purification. Septic Tanks for the Digestion of Sludge Only. — The Lawrence Tank, Hampton Tank, and Imhoff Tank. — A modification of the septic tank for the concentration and digestion of sludge only was first put into operation at the Lawrence Experiment Station in 1899. This modifi- ^ Kinnicutt, Winslow, and Pratt, " Sewage Disposal," 1910, p. 313. MI'lTIIODS OF SFWAdlC I )ISI'()SA I,. 666 f!,'iiioii consisted of ;i t:uik witli two coiiijKirt iikiiIh, tlif lowor compart- iriciil nitainiiif^ the scUlcd hIikIj^c; for wplif! lu'lion or (li;r<'.stion, while tlic iriuiri body ol'llic scwjij^c vv;is not rctiiiiutd. (\{(\)i)r\ oC Mjihh. Soth an; hased npon the priiu-iph; of" the Lawnnee tank 'tf 1eds ' \h the result of a clos(^ study of" the numerous experiments conducted at Lawrence under the State lioard of Health of" Massachusetts, etc. . , . This beinji; so, an acknowledg;ment of the source from wlience the ideas were derived and a recital of the conclusions having special referenw thereto are, as a matter of common honesty as well as of courtesy, equally desirable." The Imhotf tank is based upon the Travis tank, and consists gen- erally of two cylinders with conical bottoms connected with an upper rectangular tank through which the sewage flows. As the sewage passes through this taid'C at a slow rate the solid particles settle, slide along the sloping walls, and are deposited finally in the cylindrical liquefying chambers, reaching perhaps thirty feet below the surface of the sewage in the tank. In these lower chambers the sludge undergoes putrefaction, but the gas evolved is prevented by an arrangement of bafilles from ]>assiug up through the sewage in the upper tank. The sludge is held in these lower chambers for a series of months, and is forced out from time to time through pipes connected with the bottom of these chambers, pressure of the sewage in the upper tank being utilized for this purpose. The sludge is spread upon suitable sludge beds, where it dries (|uickly and can be removed easily to the place of final disposal. The advantage of this type of tank is that the sludge is very concentrated and practically free from odor. 1 " British Sewage Works," M. X. Baker. CHAPTER YII. DISPOSAL OF GARBAGE. Garbage eomprisos all manner of waste material, and its disposal is of very great economic and sanitary importance. The daily accumu- lation in towns and cities is enormous, and its removal at regular intervals is a matter of great concern to municipal administration. From a hygienic standpoint, the proper disposal of kitchen waste and other decomposable material far outweighs in importance the removal of such matters as waste paper, ashes, discarded boots and shoes, tin cans, bottles, and other rubbish, which in no way can affect the public health, but which for various reasons, may not be allowed to accumulate in the household. In rural districts, the disposal of garbage in general is exceedingly simple ; but in crowded communities it entails great ex- pense, and is usually a very complicated problem. Since this work is concerned solely in matters of sanitary interest, and not in economics, the consideration of this subject will be restricted to the methods of disposal of those matters, the retention of which on occupied premises may be regarded as detrimental to health, namely, those known as kitchen refuse, or swill. The methods of disposal of these matters comprise those Avhich may be carried out by the individual householder on the spot, and those adopted by municipal authority after house-to-house col- lection. In many households, refuse is disposed of by burning in the kitchen fire Math or without a preliminary process of drying, for which a num- ber of simple apparatuses have been devised. A very efficient arrange- ment in common use consists of an enlargement in the lower part of the stovepipe, forming a chamber into which, through a doorway in the end or side, the refuse, in a suitable metallic holder with perforated sides and bottom, is introduced. Through this the hot air, gases, and smoke from the fire pass on their way to the chimney flue, and thus complete drying and partial carbonization are brought about. The dried residue is disposed of finally by burning in the stove, where it serves a useful purpose as fuel. lu country and suburban districts, kitchen waste is advantageously disposed of by feeding it in a fresh and sweet condition to swine and poultry, and depositing in the soil such matters as they will not eat. Burying in the soil is a simple and eflPective method of disposal, entail- ing but little labor, since it is best not to deposit it very deeply. Near the surface, decomposition occurs rapidly, and so a covering of earth a few inches in depth is sufficient to prevent contamination of the atmosphere with noisome odors. Very recently small household incinerators have been devised for use 556 DISPOSAL OF (J Aim AGE. 557 in btiildiii^s :i]r(!a,(K)0,()(JO gallons of s(!wu<;'e are puiii|)e(l tlirounli a. tweiity-foot lift, flie works arc; lighted l)y (ileetrieity, the sh(»|)s and Corfres of the tnuniei|)al servifu; are su})- plied with power, and olhcr work also is performed. Reduction. — In the reducHion process, the kitchen pirha^'c; is stored ill tanks which p(!nnit the draining away of most f»f the water, wdiicli is c()nreventive of the spread of the disease from that person to others. An efficient disinfectant for general pur- poses should possess the property of killing not this and that species of bacteria, but one and all, and their spores as well. Some pathogenic bacteria have a tolerance for certain disinfectants, and may acquire one gradually for certain others. Such agents cannot, therefore, be in- cluded among the efficient class for general use. For special work in destroying the infective agents of certain diseases, disinfectants which have been proved to exert a destructive influence on the particular or- ganisms may be used, although they have failed to show an equal poAver against other, more resistant, varieties. Disinfectants may be divided into two classes, namely : 1. Physical agents. 2. Chemical agents. PHYSICAL AGENTS. The physical agents are : 1. Light. 2. Heat. Light. — Direct sunlight is one of the most important disinfectants known. It retards the gro^vth of many organisms, and, after a vary- 560 ril YSICA L A (J h\\ TS. Tj C, \ \n^ iiiinih(!r of hours of exposure, fiomplft/ily ar(cria was dctnon'-tiatfd first by Downos and Blunt,' in 1.S77. Tlicy inocnlat<'d flasks of broth with bactisria and exposed |)art of (lieni to .~nnliji;lit and kept the ftthers in (larkn(!ss; tlu; Ibrrner retnained clear, while the lalt(;r bef:atne turbid by reason of l)a(!t(!rial (null i plication. Mit(!holl and C/rouch ^ cxpos(!d tuberculous s|)ntiiin to direel snnliLdit for varying periods up to 25, ,'U), oTj, lo, and oo hours and then inoe- ulat(Hl it into guinea-pigs, with the result that those whi('h received sputum exi)osed longer than 25 hours remained healthy, while the others became infected. Koch'' announced, in 1890, that the bacillus of tuberculosis is killed by . pyocyancuH. 'J'he action of lijrht is considerably interfered with l)y particles in Kuspension, but with fairly clear water tlu; efleets are |ierceptil)lc! at a de|)t]i of ay)ont feet, 'i'he action of sunlight on bacteria in the [)rcsenc(! of water is believe production of hydrf)gen peroxide. Thiel and Wolf,* liowever, investigating this question, found no evidence what- ever that this agent plays any part. The relation of sunshine to the well-known resistance of tlie natives of tropical Africa to ordinary infections has been studied by Martin,' whose experiments were carried on in a district wliere the summer tem- perature in the open averages 77° F. in the early morning and at night and 144° F. at noon. Bacteriological examinations of indoor and out- door air and of the soil showed an abundance of non-pathogenic and a scarcity of ])athogenic bacteria ; and exjiosure of pure and mixed cul- tures of pathogenic bacteria to the action of the sun convinced him that while the sun's heat played a considerable part, much influence is exerted by the bactericidal action of the light rays. The obvious disadvantages of relying upon sunlight for practical disinfection are that its supply is beyond control, and that, even on the brightest days, it is impossible to apply it to all parts of a house. Nevertheless, its beneficent action may, under favoring conditions, be taken advantage of in the treatment of furniture, hangings, and deco- rations, often the most troublesome objects to disinfect, especially in a country practice. Heat. — For purposes of disinfection, heat is employed as " dry heat," /. c, hot air, and " moist heat," /. e., steam and boiling water. Steam is employed under various pressures in both the saturated and superheated conditions. In both conditions it is actually dry, although, as very commonly understood, saturated steam is associated with the idea of moisture. " Wet " steam is partially condensed saturated steam, and contains suspended particles of water. The temperature at which steam is formed depends upon the pressure ; and whatever the temperature and pressure, as ebullition begins and proceeds, the water is maintained at that temperature, and is converted constantly into steam, in which the heat employed becomes latent. Until all the 1 Annali dell' istituto d'is^iene sneriraentale della reale universita di Roma. Ill . d 437. ^ " Centralblatt fiir Bacteriologie, etc., XL, p. 781. 3 Arcliiv fill- Hygiene, XYII., p. 177. *Ibid., LYII.,"p- 2P. - Miinchener medizinische "Wochenschrift, December IS, 1906. 564 DISIXFECTAXTS AND DISiyFECTION. water has become converted, the resultine: steam is said to be safurated, since any vapor in the presence of the liquid from whicli it oripnates and in thermal equilibrium is necessarily saturated. In the saturated state, it can neither do work by expansion nor be cooled without undergoing partial condensation. When saturated steam is farther heated, its temperature rises, and it is then known, as sujjcrlicafcd ; and then, having a temperature higher than the condensing point corresponding to its actual density and volume, it may be cooled and can do work by expansion without being condensed. When very much superheated, it behaves more and more like a perfect gas, Avhile saturated steam differs, as a rule, considerably. If water at the temperature of superheated steam be mixed with the latter, some of it will be vaporized and taken up ; but mixed with saturated steam at the same temperature, no such action will occur. According to Rideal,^ the tirst recorded experiments in the sterilizing of organic matter by the application of heat were those of Needham, made prior to and during the year 1743, and the first application of this agent to disinfection on a large scale was made in 1831 by Dr. Henry, F.R.S., who treated infected clothing with hot air, and showed that the clothing of scarlet fever patients, subjected to a temperature of 200° F. for two to four hours, would not propagate the disease if worn by healthy persons. The first use of direct steam as a dis- infectant was made under the direction of Dr. A. N. Bell, U.S.N., in the case of the steamer Vixen and schooner 3fahone.s, which were infected with yellow fever while on service in the Mexican war in 1848. Knowing of this use and its observed results, at the Quaran- tine and Sanitary Convention held in Boston, Mass., in June, 1860, the committee recommended that " steam generators and steam jackets or vats be provided for the disinfection of all personal, hospital, and ship's clothing and bedding, together with such other infected goods or things as may properly be subjected to high steam heat." ^ In 1862, according to Dr. Bell, the U. S. Transport Delaware was disinfected by steam at the New York Quarantine Station on account of yellow fever, this being the first disinfection of a vessel at that station, and probably the first at any of the port quarantines. Accord- ing to the same authority. Commander Ralph Chandler, of the U. S. S. Don, from Santa Cruz, W. I., reported to the Navy Department that his vessel had been infected with yellow fever in its woi-st form (23 cases with 7 deaths), and that he had disinfected the ward room and berth deck successfully by means of steam. He recommended that vessels destined for service in the West Indies be provided with means of steaming the lower decks and holds. Dry Heat. — Dry heat is much less effective than moist heat, even at much higher temperatures and with longer exposure. Thus, air at 300° F. requires three or four times as long to accomplish the same work as steam at 212°, and possesses the additional disadvantage of ' Disinfection and Disinfectants, London, 1898, p. 20, * The Sanitarian, June, lS97s rilVSK'AL AdllNTH. r)f>5 injiiriiif^ f';i,l)ri(!,s niid oflicr <(I)J(!c|,h r-x posed U) it. Mo.st fahrir-s of voi- ton, lliusii, ainl silk will vviliislaiid an <'X|»oHiir(! of Hivcral lioiirn f,o dry heat at 2.'>()" l'\, Imi(, IxvoihI this |»i(iiil, iw'uh'.wcx-, of irnj)air<'(j ti^tiHile stnitif^th 1h soon niani(c,->lc(l, Jwcn at 002*^ ¥. (150'^ C.j, dry lur-'it wsw found by Koc-li and \Volll"lnin;('l lo he not always cWi-cXw't', even after two hours, wliilc l)oilin I nv-i-tniil oC (lie, |)yoj.'-ciiic baf;- t(!ri;i — Hihi,j>liiili)r(icfi(H aiircn.-: — I lie ihiiIidi- (oiiiifl not one that, f,oijl'l r«'- .si.st l)()ilin<^ more IIimii a iniiiiilc ;iii(i ;i li;ili. Fit;'. !)() shows a sicfili/iii;; liopjMr devised \>y V. A. Wasliljiirii, M. I)., Sii|)eiMiit('iiden(<)(' (Ik; Massacliiisetts (leiiei'al Hospital. 'I'liis h()p|)Cl' is used instead o(" clieniieal a<:;enl> ('oi- I lif disinfeet ion <((' typlioiil stools and urines. In (M)ininon daily use tlu; ^ate valve of (lie liopper i-; open, tlie eover is up, and the steam, of course, is not turneil on, WIm-u it is to Ix; uwd for sterili/in|L!; juirposes tlu; nate valv(! is closed, the l»(;, Xo. 7. ■•^ Fortsclu-itte der Mediciu, May 15, 1893. 570 DISINFECTANTS AND DISINFECTION. Fig. 96. ja /CALCOFiKiCHCX LEGEND. <; "A"=JTEAM PIPE, INLET ^- OUTLET. B"- >5EWER.Te.AP 'C'= dATE VALVE. 'D'"-- FLEXIBLE TUBE •E''= WATEB J-UPPLY. T'=VAPOB VtNT. 'G' = TtiAP VENT. "l-l"- PAINTED LINE. "I"- 3EWER, PIPE. ;j'^ VALVE HANDLE. 'K ■ COVEC. "U- TI^,AP CLEANOUT "M'-IilM OF WATE5^J"EAL DETAlLOPJ'EALj DRIP. RIM ^ ^-pocicEr "TT COVtH, ELEVATION. '°" '5. r^. nc / 5AJE J-CALE or INCHEwT. ^ sterilizing hopper used at Massachusetts General Hospital. CIIKMWAL AdlCNTS. 571 tho r(!HiiliH wen; nc^ufivc In oilier cxjxTirrKtiitK in wliittli frcfzin^ \sn^ int('i-iMi|)t(;(l, no ora;aMisrns were found wWcr and 7 dayH. Hut W'lik- now ' l<(^|)i tli(!tn alive nior-e llian a nionlli af — .'52.5'^ (J., and ChrJH- lian ■" liUH .shown thai, iuidf cold for a loufj^ time. 'I'liis was well shown in the (txperienr-e of I'ly- moiit.h, I*a., wiicre, in l.SSf), a most d(!vastaling epidemic occurred after the thawing out of an actcuniiilatioii of tyj)hoid e-xcrcta situated near a brook which supplied tlic town witii drinking-water, and at Ogdens- l)in-g, N. Y., where an oulhn^ak was traced to ic(! that had heen housed 9 months before. The bacilli of diphtli(!na have been proved to hv. virulent after G months' continuous freezing, sometimes at — 25° C., and those of plague have been found to be about equally resistiuit. The ex(H'edingly low temperature of lifpiid air, — 312° F., a[)pears to have no elTecit on organisms exposed to it for slu)rt or long perioSf.. j>/i()sj>h(>i-csc(')L!<, a sarcina, a saccharomyces, and unster- ilized milk, hermetically sealed in fine quills, to the refrigerating in- fluence of liquid air for 7 days, and at the end of this time the quills were withdrawn and allowed to thaw. Culture experiments proved that the vitality of the various micro-organisms was in no way imjiaired. Every species grew well, the ])hotogenic bacteria grew and emitted light, and the milk became curdled. Later, Macfadyen ^ exposed the organisms for 6 months, and in no case was there any appreciable eflfect upon their vitality. CHEMICAL AGENTS. The list of substances falling under the head of chemical disinfect- ants is very long, and includes a wide variety of organic and inorg-anic compounds, some of which are gases, some liquids, and others soluble salts. While it is very long — for almost any chemical substance pos- sesses under one condition or another a certain degree of bactericidal power — the number of agents which may be regarded as trustworthy in actual general practice is exceeding small. Many substances which have a high reputation for efficiency are found to be actually worthless when subjected to modern methods of testing, and others which yield promising results in the laboratory are found often to fail when used under the conditions which obtain in practice. The undeserved reputation of many preparations is based wholly upon the apparent influence which they have exerted in limiting the spread of infectious diseases, and it has not been impaired by unex- iWratsch, 1S93. Xo. 8. * Aichiv fiir Hvsjiene, LX., 1909. No. 1. 3 The Lancet, April ;21, 1900. * Proceedings of the Eoyal Society, LXXI., 1902, p. 76. 572 DISINFECTANTS AND DISINFECTION. plainable failure to accomplish the same result at other times. Au out- break of au iufectious disease occurs, for example, in a boartliiig-school, aud duriug its coutiuuance a number of bottles of some proprietary- preparation are used ; no further cases are rei)orted, and the credit is given to the disinfectant. Six montlis later, perhaps, another outbreak occurs, and, in spite of the use of the same agent, it spreads and the school is closed ; this result is not charged on the other side of the account, but to the inscrutable ways of Providence, and the fame of the disinfectant is in no way injured. In many iustauces, strength and peculiarity of odor are the only qualities necessary for the building up of a reputation for efficiency, for man is wont to attribute potent prop- erties to unusual things. ]\Ianv substances have undoubted germicidal power over certain forms of bacteria, and are quite inert against others ; some will kill every known form under some conditions, and yet may wholly fail to affijct bacteria of slight resisting power protected by mucus or other matter, or may even be rendered inert almost immediately by chemical union with some other substance accidentally })resent. Chemical disinfectants act in various ways to bring about the de- struction of bacteria. Some act directly upon the bacterial protoplasm and cause its coagulation ; some bring about changes in reaction favor- able to life and growth ; some destroy nutritive material by chemical change ; some take up all the available oxygen, thus becoming them- selves changed in character while depriving the bacteria of an essential element ; and others bring in such an excess of this same element that the bacteria cannot withstand its action. Some even stinudate multiplication, and thus act only indirectly by promoting the formation of organic compounds which exert a destructive influence upon the organisms by which they have been produced. The disinfectant power of many of the metallic salts depends partly upon the nature of the solvent. DifTerent agents produce their best results in different degrees of con- centration ; thus, while one may be efficient in 5 per cent, solution, another may act equally well or better in 0.10 per cent, or even weaker solution. Some agents, as, for instance, alcohol, are most bactericidal at some one point of concentration, and above and below this the prop- erty progressively diminishes. In applying any agent whose best work- ing strength is known, it should be borne in mind that it is not suf- ficient to use a small volume of solution of that particular strength, but that the substance itself must be employed in such an amouut that it shall be present throughout the whole mass in the proportion required. Thus, au agent which is effective in 2 per cent, solution cannot be used in that strength to disinfect an equal bulk of infective material, since the mixture would then contain but 1 per cent. Non-metallic Elements and Their Compounds. Oxygen. — The disinfectant property of pure air is due to its oxygen, which attacks organic matter under favorable conditions and NON-Mh'/rAI.LK! KLI'.MKNTS AND 'I'll Kill COM fony DS. 573 convcfis il, ill <^rc:il |»;iii lo ciiilxni (lidxiilc ;iii(l \\;it\i<\\^i-i\ aenitioii is ri^lilly rc<;;ii'(lc(l ;is ;i \;ilii;il)lc ;i:-:-i-l;iiit in (li-iii("(<'li«'(l to moving (MIITciiIm oCoiildiidi- ;iii', llir\ ;iic -iilij' 'led ;i| o to (lie jtowcrCiil iiiMiiciK'c (•(" ( lie clicniiciil r;i\-.s dl" siinlinlil ;iii(l In the jxtssihilil y of doic- catioii. ().\Nncii :icls inosi puw (•rCiilly in tin' iKiscciif stale, iiH wlicii liborutcd (Voiii coniixiiiiKls w lidsc (l<<'.,hi|i()>ili(tn n'-nlt- in tlu; CHrsijJC <»f* the ^!is in tJic (Vcc coiMlilion. AinnnL; lli<-f r(iin|ionii(ls, o/.tiiic, (lie allotropic/ lurni o(" oxygen, (•ftntainin;^ in ladi inolcciilc tlircc atoriiH instead of two, and liydroo(Mi peroxide, may lie inentiftiied as eoiispir-ii- <)US ('Xaniples o(" oxi
  • iiiall amounts. Krukowitsch, quoted by Kowalkowsky,' experimentintr, in 1882, with putrefactive bacteria, found that -'> milliu:i'ams of ozone jier cubic meter of air killed fresh l)acteria, exposed on pa})er, within an honr, and 8 milligraius ])er cubic meter sufficed to destroy the dried organ- isms. Later (1888), Lukaschewitsch, experimenting with B. stihti/is, B. anthraeis, Sp. cholei^ce Asiatica;, and certain putrefactive bacteria, olitained results which were less favoi-able, luit in agreement in so far as they demonstrated the relatively slower action exerted on dry bacteria. Spores of B. sr(btilh and B. anthraci'i in a dry state were unaffected by 1.50 grams of ozone per cubic meter, and the comma bacillus, in a moist condition, was not afiected until after 15 hours' exposure to the same atmosphere. Ohlmiiller^ employed a much greater strength, namely, 15 grams to the cubic meter, and conducted the air through distilled water, in which bacteria were suspended. Water containing anthrax spores was sterilized in 10 minutes by 89.9 milligrams of ozone; and contain- ing millions of typhoid and cholera germs to the cubic centimeter, in 2 minutes by less than 20 milligrams. River-water and sewage were found to be much less aftected, but with only moderate pol- lution it appeared probable that in ozone might be found a cheap and efficient means of purifying drinking-water. Later on, a number of processes were devised for this })urpose and carried out on a large scale. In the hope of arriving at some definite conclusion as to the avail- ability of ozone as a room disinfectant, Kansome and Foulerton ^ coa- 1 Zeit^chrift fiir Hygiene, IX.. p. 89. 2 Arbeiten aus dem kaiserliohen Ge;j Sternberg, then chairman of the committee of the Am(a-ican Pui)lic Health Association, to which, in 1884, the subject of disinfectants had been referred, took very different ground regarding this and other hypochlorites, and as- serted their efficiency in no uncertain terms. Since then the matter has been the subject of many investigations by competent observers, and while in some hands the results have failed to be uniformly favor- able, the work, as a whole, has sustained the position taken by Stern- berg as a result of his own experiments. Woronzoff, Winogradoff, and Kolesnikoff^ demonstrated that anthrax spores were killed in 1 minute by a 5 per cent, solution, although in Koch's experiments they had been found still active at the expiration of 2 days. Jaeger,^ in 1889, concluded, after a series of tests with a number of species of pathogenic bacteria, that it is a very efficient disinfectant, even in weak solutions. Nissen,* in 1890, after a series of careful experiments, reported that the organisms of cholera and typhoid fever were destroyed in 5 minutes when the material in which they were present contained 0.12 per cent, of the agent, and in 10 minutes by half that amount. Anthrax bacilli were killed in 1 minute by 0.10 per cent. ; Staphi/lococcus pyogenes aureus and Strepto- coccus erijsipelatis in 5 minutes by 0.12 and 0.15 per cent., respectively, and in 1 minute by 0.20. Anthrax spores of low resistance were de- stroyed in 15 minutes by 5 per cent, and in 70 minutes by 1 per cent. Very resistant spores, capable of surviving 4 hours' immersion in 0.10 1 Mittlieiliingen aus dein kaiserlichen Gesundheitsarate, II., p. 228. 'CentralblaU fiir Bakteriologie, 18S7, p. (i41. 3 Ai'beiten aus dem kaiserlichen Gesundlieitsamte, V., p. 247. * Zeitschrift fiir Hygiene, YIIL, p. 62. 5" 6 DTSIXFECTAXTS ASD DISIXFECTION. per cent, corrosive subliinnto aiul 10 mimites' exj)()sure to streaming steam, were killed in 4.5 luuirs hy 5 per cent. Klein,' experimenting with sodinni hypochlorite in 10 per cent, so- lution (1.0 per cent, chlorine) on the colon bacillus, anthrax spores, Staphylococcus pyogenes aureus, B. enteriUdis sporogenes, and tlic bacteria of tvphoid fever, cholera, and s\vine fever, found that all \\-ere killed in 20 minutes, and the non-spore-bcarers in 10. In one-tcntli as strong solution, all but the two kinds of spores were destroyed within 20 minutes. Duggan,- working according to Sternberg's method, reported, in 1885, that his experiments had shown "that a solution containing 0.25 per cent, of chlorine as hypochlorite is an effective germicide, even when allowed to act for only 1 or 2 minutes, while O.OG per cent, will kill spores of B. anthracis and B. subtilis in 2 hours." The composition of "chloride of lime," or, more properly, chlorinated lime, and its mode of action, are matters concerning which there is con- siderable disagreement. The substance is held variously to be : (1) a mixture of calcium chloride and hypochlorite ; (2) calcium hyjiochlorite in which one CIO is replaced by CI, that is, Ca(C10)Cl, which, in con- tact with water, is broken up into calcium chloride and hypochlorite ; (3) a compound of calcium hypochlorite and oxychloride with 4H2O, formed according to the equation 4Ca02H2 + 2CI2 = CaO^Cl.,. Ca302C].,4H,,0, which is split up in water into calcium chloride, hypochlorite, and hydroxide ; and (4) a compound of calcium chloride with hydroxide, of which one H is replaced by CI. It is white or whitish in color, and occurs as a powder or as friable lumps ; it should be dry or nearly so, and should have no more than a faint odor of chlorine, which element should be present in available form to the extent of not less than 35 per cent, to conform to the requirements of the U. S. P. (British standard = 33 per cent., German standard = 25 per cent.). AVith keeping, under vai'ious conditions, chlorinated lime may undergo decomposition in a number of ways. A pasty condition or a strong odor of chlorine is evidence of partial decomposition. It is only par- tially soluble in water, and its aqueous preparations are made best by triturating the requisite amount with water to th(i consistency of cream, and then diluting to the desired volume. The addition of acids to the solution causes evolution of chlorine, but the carbon dioxide naturally present in the water or absorbed from th« air decomposes the hypo- chlorite, yielding calcium carbonate and hypochlorous acid, the latter of which breaks up into active oxygen and free hydrochloric acid. (See Hypochlorous Acid, p. 577.) The solution known as the "American standard" contains 6 ounces of the powder to the gallon. It is used largely in the disinfection of discharges, and for scrubbing floors and other woodwork. A weaker 1 The Lancet, Nov. 26, 1896, p. 509. 2 Report of the Committee on Disinfectanf? of the American Public Health Associ- ation : Baltimore, 1885, p. 12. NON-MKTM.I.K: hLKMh'NTS AND Til Kill COM I'OfJSDS. 577 Koliii.ioii is ciiipldycd (or llic I icil incut nl' inrcclcd hcd-lincii and Wiiwli- ;il)l(! (;l()tliin^, bill i»ii .iccoiinl of its dcsl iiic(iv(! action, flx-Hc articlcH slioiild, iillcr ;t not, loo lon^j iinnni-ion, l)c wii-li'd f lioroiijriily in plcnfy of (Vdsli vvaicif. Sodium hypochlorite solution, otlicrwisc! known mh fliloririatfKl Koda, Lal)aria(|n('s solntion, ami li(|nor sochc (tlilorata;, i.s "an afjUcoUH solulion <)(' scNcial clilorinc conipoiMidH of" Hodinm, cliicfly NaClO and NaX'I, and conlainin}^ at least U.H per cent. In' wcMTrlit f)f availahlf; (^liloiinc, " (U.S. P.). It is used, hnt not so extensively, for tlie same pni'poses as clilorinaU^d linic. Hypochlorous Acid. — It Ixinj^ not iin|)rol)aljlo tliat <'liIorine in solntion in water exerts its disinCcetant action as iiypoeiilorous acid, Andi-ews and Orhon ' tested the hacterit^idal |)ropcrties of" preparations of" the pure acid and found tliein to be of the. most intense character, anthrax spores Ixmiij^ very (piickly destroyed hy the acid in extreme dilution, wiien they were suspended in pure water. Tiie presence of organic matter, however, causes the very unstable acid to decompose very rapidly, so that whereas l^fdjtlnjIiK-occnH j)i/of/nifN aurcua in dis- tilled water was killed inniiediately by 1 : 100,000, in veal brotli it was killed only within 30 minutes by 1 : 3000. But it was found that the germicidal power of l)leaching pc'iwder solution is increased by the addition of a weak acid (acetic or carbonic) to liberate free hypochlor- ous acid (a strong acid liberates free chlorine). Thus, a saturated solution containing 5 per cent, of calcium hypochlorite required between 7 and 10 minutes to destroy dried anthrax spores, while the same solution diluted with two volumes of 1.25 per cent, acetic acid killed them in less than 1 minute. Iodine has powerful disinf"ectant properties, but is more suited to the purposes of the operating room than to general disinfection. The experiments of Kinnamou - indicate that in solutions of 0.2 to 1 per cent, it is far superior to corrosive sublimate — 1 : 1000. The latter required 15 minutes for the destruction of streptococci, while iodine (2 : 1000) killed them in 2 minutes. Iodine possesses the advantage over corrosive sublimate that it neither coagulates albumin nor forms inert comjiounds M'ith the tissues, and in effective strength is non-toxic and non-irritating. Dannreuthcr ^ considers the tincture the best means of sterilizing a dirty wound, and an excellent agent for sterilizing the skin before incision and for limiting the extension of the erysip- elatous rash. Bromine. — While bromine has marked disinfectant properties, it is disagreeable and dangerous to handle, and, according to Kinnamon,^ is much inferior to iodine in all respects. Its use in the puriticatiou of water has not been markedly successful. (See chapter on Water.) Sulphur dioxide easily outranks all other disinfectants in point of 1 Centralblatt fiiv Rakteriologie, etc., I. Abth., Originale, 1P04, XXXV., p. 645. 2 Journal of the American Medical Association, Aug. 26 and Sept. 2, 1905. 3 Medical Eecord, January 25. 1908. * Journal of the American Medical Association, February 1, 190S, p. 345. ?7 578 DISINFECTANTS AND DISINFECTION. \eT\gih of service, its use dating liack to very ancient times. While it has undoubted bactericidal properties, it has been demonstrated by- Koch, AA'olffhiioel, and their associates, and many others, to be wholly untrustworthy lor general use, and although still very extensively employed by public sanitary authorities, is rapidly being abandoned in favor of more efficient and reliable agents. It is purely a surflice dis- infectant un(ler conditions nuxst favorable to its action, and even then is effective against only a somewhat limited number of species of patho- genic-bacteria. Sulphur dioxide is a colorless irrespirable gas, produced by burn- ing roll sulphur or " flowers " in an iron vessel, ])laced as a precaution against fire in a pan of water, or by burning sulphur candles or carbon disulphide, the latter in a lamp. The amount of sulphur employed varies, according to the custom of the operator, from 1 to 6 pounds per 1,000 cubic feet of air space ; but the whole amount is never con- sumed, and, indeed, under ordinary circumstances, combustion ceases before a half or even a third has been burned. In order to avoid the necessity of burning sulphur, the liquefied gas, contained in cylinders, is employed to some extent. In the absence of moisture, the action of sulphur dioxide on even the least resistant bacteria is practically nil, and even when water is evaporated in the room beforehand or at the same time, and the gas is present in the highest percentage possible, the exposed organisms, whether of low or high resistance, are likely to retain their vitality unimpaired. It is true that some experimenters have reported great success in the destruction of pathogenic organisms by means of this agent, but the adverse reports are so numerous that it must be clear that much official disinfection by means of it is worse than an empty form and, by reason of causing a false sense of security, a posi- tive danger. Even were it an efficient disinfectant, the many disad- vantages which attend its use would suffice to make it undesirable for general purposes, especially in view of the fact that the same disad- vantages are wholly absent in other processes. In the presence of moisture and air, it is to some extent oxidized to sulphuric acid, which corrodes fabrics and other objects ; it reduces organic matters and destroys organic colors ; it tarnishes brass and silver ware, gilt frames, and other objects ; it leaves a disagreeable odor which persists for days and even weeks after thorough aeration ; bedding and other articles become impregnated with a peculiar highly offensive odor which renders their use unpleasant and even impossible ; and it has such little power of penetration that only such organisms as are exposed openly are likely to be affected. Where sulphur dioxide is the official disinfectant, it is commonly enjoined that the room shall be cleansed thoroughly and air freely ad- mitted for some days after fumigation. The necessity of this supple- mentary process is in itself an admission of the inadequacy of the main operation, for if sulphur is an efficient disinfectant, the application of soft soap, carbolic acid, hypochlorites, and other agents by means of SODIUM CM: IK )\' ATI':. 579 tho Hf!rul)})iii<^-bniHli mikI cIoIIi.'^, I Ik- removal and vc\)\:v'\u\r of wall- j)a,|)(!r,s, ili(! |)r(»<;(!,ss oC wliilc-waKliiiifr, and other means oC renovation rc'eoiiiiriciidcd, aro attackH aj^ainsl, an ima^dnary evil, (irant^-d that th(!M(! processes are nwiessary, the claims of snlj)hnr dioxide an a prae- t.ieai disin(e(U;ant, must, (ail to tlie gronnd ; if n(*t riocoHHary, thf;y hhould not he enjoiiu'd. Althongh not an enicicnt di.sinfeclanl, snlpimr dioxido is an exceed- ingly valuable .-ifj^cnt for i\\v. destrnetioii oC mosquit^jes in houses where malaria and yellow fever an? rife (see eha|)ter on Tlie Relation of Insects to Human Diseases) and of rats in ships' liolds (see chapter on Naval and Marine Hygiene). Sodium Carbonate. Sodium Carbonate, or " Washing Soda," used in every household as a cleaning a iidd :il, K-.-isI; im c;fjii;il volume of" llw milk, or ^•v^'^\ twice ;is iniicli, :iiiS'^. pyogenes albus, B. pyocyaneus, and B. coli were killed in less than a minute and a half. Silver Compounds. — In addition to the familiar fluoride and nitrate a considerable number of organic compounds of silver have within recent years come into use in various special fields of medical practice, and for them are claimed great bactericidal efficiency. Ac- cording to Marshall and Neave,^ those which are powerfully bacteri- cidal include the nitrate, the fluoride, actol, itrol, argentamine, albar- gin, argonin, ichthargan, largin, novargan, and protargol ; nargol is much inferior ; and argyrol and collargol are practically inert. With these findings, those of Derby ^ are in substantial agreement. Argyrol 1 Boston Medical and Surgical Journal, January 14, 1904. ^ Annals of Surgery, Octolaer, 1904. 3 British Medical Journal, August 18, 1906, p. 362. * Transactions of the American Ophthalmological Society, 1906. MI'lTALLK! SALTS. 685 and (U)lliir^ol wen; foiiiHl lo Ix' very weak in action ; thf; nitraU- in 0.5 to 2 IXT (; minnt(!S. Mineral Acids. The minei'al aeids ])ossess, in dill'erent degrees of dilnti(jn, var^'ing disiideetaut power against all species of bacteria. Jn any effective working strength, they eorrod(' the eominon metals and destroy the tensile strength of all kinds of fabrics. The bactericidal effect of gastric juice on the bacteria of cliolera, dis- covered by Koch, was ascribed by him to the contained hydrocliloric acid; and experimenting with bouillon cultures of this organism, Kita- sato^ showed that 0.1 o2 ]ier cent, of hydrochloric or 0.04!J of sulj>hnrie acid produced sterility within a few hours. This result, so far as it concerns sulphuric aeid, was confirmed by Stutzcr,^ who found that 0.05 per cent, killed in 15 minutes the organisms suspended in dis- tilled Mater. The experiments of Boer ' showed that the l)aeillus of tyjthoid fever in bouillon cultures was destroyed in 2 hours by 0.07 per cent, of hy- drochloric acid, and in the same time by 0.12 per cent, of suli>huric acid. The cholera organism was killed by smaller amounts, 0.02 per cent, of each, within the same time ; the bacilli of anthrax were but slightly more resistant than the cholera germ ; and those of diphtheria succumbed to the same amounts as were fiital to those of typhoid fever. Ivanoff^ determined the amount of sulphuric acid necessary to sterilize sewage. That of Potsdam, three times as foul as that of Berlin and slightly alkaline in reaction, impregnated with cholera germs, was disinfected by 0.08 per cent, in 15 minutes. A proprietary preparation, containing 0.76 per cent, of sulphuric acid and nothing else, tested by the author, sterilized one of two bouillon cultures of ty])hoid bacilli and one of two typhoid dejecta in 2 hours, but had no effect whatever on diphtheritic membrane and tuberculous sputum. 1 Journal of the American ^redical Association, Januarv 27, 1906, p. 270. » Zeitscbrift fiir Hvdene, III., ISSS, p. 404. 3 Ibid., XIV., 1893,^ p. 9. * Ibid., IX., 1890, p. 479. 5 Ibid., XV., 1893, p. 86. 586 DISINFECTANTS AND DISINFECTION. Carbolic Acid and Cresol Preparations. Carbolic acid, phenol, phenic acid, obtained chiefly from coal, is a substance of varying degrees of purity and disinfectant power. The highest grade is practically pure phenol, but the commoner qualities contain variable amounts of cresols, xylol, and other higher homo- logues, all of which have marked bactericidal properties, and tar oils which have none. In the opinion of many authorities, the crude acid is superior to the highest grades in disinfecting power by reason of the presence of the cresols. Prior to Koch's work on disinfectants in 1881, carbolic acid was believed generally to be one of the most powerful of germicides, a belief which was due doubtless, in part at least, to its peculiar and power- ful odor. Koch's experiments with anthrax spores led him to the conclusion that, even in 5 per cent, solution, it was an inefficient agent against highly resistant organisms. Then followed a number of in- vestigations by others, whose conclusions were by no means in agree- ment. It was found by some to be a very efficient general disinfectant, by others to be very unreliable, and by still others to be well suited to some lines of work and not to others. It was conceded very generally that in certain respects its use has many advantages over that of cor- rosive sublimate and other metallic salts ; that it is not destroyed or precipitated by contact with albumin, acids, salts, and other com- pounds ; and that, even in weak dilution, it destroys many of the com- mon pathogenic organisms very quickly. Behring, Sternberg, and others found it effective against the bacilli of typhoid fever and cholera in 1 per cent, solution, but opposite conclu- sions have been reported as to its action against the former, which organ- ism is said to flourish in mixed cultures in the presence of even as much as 5 per cent., the accompanying species being destroyed. For the disinfection of tuberculous sputum, Schill and Fischer ^ found it to be reliable in 5 per cent, solution within 24 hours. An experiment by the author and Dr. R. M. Pearce,^ in which this material was treated with 17 different preparations, proprietary and otherwise, including a 5 per cent, solution of carbolic acid, was successful with this agent and 4 others after a 2 hours' exposure. With typhoid stools, diphtheritic membrane, and bouillon cultures of the typhoid organism, disinfection was not accomplished. Against pus cocci and B. pyocyaneus, the 1 : 20 and 1 : 40 solutions act with considerable rapidity. In a series of experiments with differ- ent strains of Staphylococcus pyogenes aureus and albus, B. pyocyaneus, and B. coli, conducted by the author,^ the organism first mentioned, which is the most resistant of all the common pathogenic bacteria to most chemical disinfectants, was killed uniformly v/ithin 2 minutes by the 1 : 20 solution and within 4 minutes by the weaker preparation. All of the other organisms succumbed even more quickly. That the ' Mittheilungen aus dem kaiserlichen Gesundheitsamke, II., 1884, p. 145. ^ Loc. cit. 3 Annals of Surgery, October, 1904. t'AIiliOIJC Ar()\<)i\^cnal rcsisti/if,^ power against atrtaiii hactcriciclal aj^critw, and eni[)lia8izos the; importance of employing in experimental wrjrk the witlesL |)ossil)l<' variety of" haeterial speeies undctr like eonditions before forming un opinion ol' tlie value oi" a given snhstanee for gr-neral dis- infe(!tant purposes. The j)resene(; of small amounts of min(!ral aeids in solutions of ear- bolic acid is shown by Frilnkel and Laplace to he very lielpfiil, hut it is to he home in mind that th(! fornwr, unassisted, are hy no means without a very considerable degree of germicidal j)ower. Jioth authori- ties, however, have proved that mixtures of carbolic and mineral acids are more bactericidal than either ingredient in the proportions used, and both, and No(;lit as well, have d(;monstratcd also the superir)rity of mixtures of the crude acid with mineral acids over combinations of the pure phenol with mineral acids in the same proportions. According t.o Epstein,^ carbolic acid in alcoholic solution is more powerful in the same amount than in a(pieous solution, which finding is endorscnl by Mincrvini.^ On the other hand, in solution in oil, according to Koch, it loses its germicidal property completely. This is because, being more soluble in oils than in water, it does not leave the oil to penetrate the bacterial cell. The experiments of Heller'' with mixtures of carbolic acid and the green soap of the German Pharniacopfcia, using cultures of B. typhosus as tests, indicate that the soap, which possesses but slight bactericidal power, increases that of phenol in a marked degree, especially when the two substances are present in equal parts. While the organisms were killed in 20 minutes by the carbolic acid in 5 per cent, solution, they were destroyed in the same time by a 4 per cent. sf)lution of the two agents in equal parts ; that is to say, by less than half the required amount of the acid alone. The reason for this increase in power may be that a new complex compound of greater bactericidal power is formed, or that the presence of the soaji increases the rate of dissocia- tion of the acid. The so-called carbolic powders are, as a rule, inert mixtures of mineral matter and waste products of coal-tar distillation. Their strong odor appeals to the imagination and promotes their sale. Cresols (meta-cresol, ortho-cresol, and para-cresol), which occur as impurities of carbolic acid, and, according to many authorities, are more powerful as germicides and less poisonous to higher organisms, are constituents of a large number of preparations which, within recent years, have come into extensive use. The cresols are closely related to phenol, from which they differ in that CH^ replaces one H in the benzol ring, and according to the position of CHg, we have meta-cresol, ortho-cresol, or para-cresol. The latter may be made synthetically from pure para-toluidin. Cresols are practically insol- 1 Zeitscbrift fiir Hvsjiene und Infectionskranklieiten, XXIA'., 1S97, p. 1. » Ibid., XXIX., 1898, p. 117. 3 Archiv fiir Hygiene, XLVII., p. 213. 588 DISINFECTANTS AND DISINFECTION. uble in water, but solution is brought about by soaps auJ by cresol salts. Laplace ^ was the first to dra\v attention to the fact that crude car- bolic acid and strong- sulphuric acid, mixed together, tbrni a c(Mn])ound soluble in water and of high disinfectant po\ver. He reported that the mixture in 4 per cent, solution destroyed anthrax sj^ores within 24 hours, while pure carbolic acid in 2 per cent, solution had no effect wliatever. The first extensive study of tlie action of cresol was made by Friinkel,^ who showed that the mixture of suljihuric acid and crude cresols is not of the nature of a new compound, but that each ingredient exists by itself and exerts its own action, and that the acid keeps the cresols in solution. Hammer^ investigated the j^roperties of cresols dissolved in sodium meta-cresotinate ; here, also, no double compound is formed, the salt acting merely as a solvent. Sodium salicylate acts equally well as a solvent. The various preparations containing cresols and solvents of the same are recommended highly as substitutes for phenol, on the ground of higher bactericidal power, lower toxicity, and of being less irritating in surgical M^ork. They may be diluted at will with water, some forming milky emulsions, some clear solutions. From a study of the comparative disinfectant action of the several cresols and of several other preparations, including tri-cresol (prepared synthetically from toluene) and phenol, Seybold * concluded that of the three isomers, meta-cresol is the most powerful, and that the cresols are all superior to phenol. Tri-cresol, which is 40 per cent, meta-, 35 per cent, ortho-, and 25 ])er cent, para-cresol, proved to have double the bactericidal power of phenol against B. pyocy emeus, B. jirodigiosus, and Staphylococcus pyogenes aureus. Another preparation of cresol, made by another manufacturer and examined by Schiirmayer,^ also proved to be far superior to phenol and to a number of the more com- monly known cresol compounds. Experiraeuts with tri-cresol, con- ducted by the author, demonstrated considerably greater bactericidal efficiency than is possessed by phenol or any of the cresol preparations obtainable. Among the more commonly used cresol preparations may be men- tioned the following : Liquor Cresolis Compositus (U. S. P.). — This is a liquid soap con- taining 50 per cent, of cresols. It is a thick, dark-brown liquid, mis- cible with water, and is made by adding 350 grams of linseed oil to 80 of caustic potash in 50 of water, mixing thoroughly, and then add- ing 500 of cresol, and finally enough water to make 1000 grams. The experiments of McBryde^ show that it is very considerably superior in 1 Deutsche medicinische Wochenschrift, 1887, No. 40. ^ Zeitschrift fur Hygiene, VI., 1889, p. 521. 3 Archiv fur Hygiene, XH., 1891, p. 359; XIV., 1892, p. 116. * Zeitschrift fiir Hygiene und Infectionskrankheiten, XXIX., 1898, p. 377. 5 Archiv fur Hygiene, XXV., 1896, p. 328. ® Bureau of Animal Industry, United States Department of Agriculture, Bulletin No. 100, May 31, 1907. (JAni'.OLKI ACID AND CILESOL I'lLia'A ILATIOSS. r,80 tlu! '. I.1JJ//1JMUH, SbijiliijIdcorrtiH 'fyjiof/nwH aumiH, II. jfi/'>- cjldncm, and />'. ch.olr.nv. hum U) cjirlxdic arid cm ployed in tlu; Kinu; (lihil-ioii. iLs j^crnil(ri(lal (•(licicncy is j(rc:if<:i- flu- lii^^licr tlic hr.ilin^- poinl, of (li(! ci-csol it (!(>iil;iins, and licncc is lowcsl. wlicii tlic prepara- tion Ih mad(; wil.li (»i'l:li()-crc,-,ol ; ;iiid even tlicn ii is n<,'arly oik; .-ukI oih;- lialf tiin<\s n'parati(jns bearing tlii.s name! vary greatly in composition ;ind properties, even when coming from tlu! same manufaeturor. Mixed with water, ereolin forms a tur- bid, wliilisli emulsion. Specimens examined by Jtideal varied gr(r:itly in germicidal (!ni(MeucA% but were uniformly su])erior to carbolic; aeid in equal strength. That (sxamined by I liinerman ^ proved tf 1 per cent, of these substances present in this dilution. On account of the variability in the composition and bactericidal properties, one manutacturing company has abandoned the name and adopted for its pi'oduct the name Cyllin, which substance is said by Klein ^ to be more than twenty-seven tiiiies as efficient as phenol. Lysol is a brown oily liquid containing about 50 per cent, of cresols with neutral potash soap, miscil>le with water in all ]iroportions, form- ing a soapy, frothing liquid, and with alcohol and glycerin. Gruber^ found a 2 per cent, solution more effective against pus cocci than a 3 per cent, solution of phenol. Buttcrsack's * experiments led to the same conclusion, and demonstrated also its suitability for the treatment of sputum. In the hands of the author,'' iiowever, it acted less quickly against Staphylococcus pi/ogcnes aureus and albus than carbolic acid and tricresol in the same dilutions — 2.5 and 5 per cent. Vincent ^° found it to be a valuable agent for the disinfection of faeces and vault con- tents. In surgical practice, in which it is used exclusively, instances of poisoning through absorption, sometimes with fatal results, have 1 Public llealtli. December, 1903, p. 156. 2 Centralhl-.itt fiir Pxikteriolosiie, Y., 1889, p. 650. 3 Ibid., VI I., 1S90, p. 75. ^ ♦ Ibid., XII., 1S92, p. 232. s Journal of tbe Sanitary Institute, Nov., 1903, p. 425. 6 Public Health, June, 190-i, p. 566. ^ Centralblatt fiir Bakterio''.02;ie, XL, 1892, p. 117. 8 Arbeiten aus deni kaiserlichen Gesuniiheitsamte, VIII., 1892, p. 369. ^ Annals of Surpery, October, 1904. 10 Annales de I'lnstitut Pasteur, IX., 1895, p. 26. 590 DISINFECTANTS AND DISINFECTION. been numerously reported. Its use in Berlin, and elsewhere in Ger- many, for suicidal purposes has become so widespread as to cause grave concern. Bacillol is a product of the distillation of tar, and contains variable amounts of cresols according- to source, but should contain not less than 50 per cent. It is very cheap and, as may be inferred from its content of cresols, is very efficient in 5 per cent, solution, Saprol, — This is a liquid containing 20 per cent, of mineral oil and 80 per cent, of crude carbolic acid. It is lighter than water, and when thrown into it diffuses over the surface in a thin layer, which gradually yields its active ingredients to the strata below, which, in the course of a day, become impregnated to the extent of about 0.34 per cent. In this strength, according to Scheurlen,^ it destroys cholera bacteria in 1 hour. For the disinfection of privy vaults, Keller ^ determined that it must be added to the extent of 1 per cent, of the entire contents. In mixtures containing 5 per cent., the same observer showed that the typhoid fever bacillus is destroyed within a few minutes. Pfuhl ^ found it to be much superior as a general disinfectant and deodorant to carbolic acid, but not suited to the treatment of vault contents. Laser,^ however, found that 1 per cent, will disinfect faeces and urine ; and Scheurlen ^ reported that for the disinfection of vault contents but two other agents are comparable with it, namely, milk of lime and crude carbolic acid. Solveol is a concentrated aqueous solution of cresols with sodium cresotinate, containing more than 25 per cent, of cresols. It is highly recommended for use in surgical practice, being unirritating and much less toxic than carbolic acid. According to Hammer,^ it is more power- ful in 2 per cent, solution than creolin, lysol, and carbolic acid in 2.5 per cent, strength. Hammerl ^ also found it superior to carbolic acid and the other cresol preparations. A specimen tested by the author, however, was found to be markedly inferior to carbolic acid, tricresol, lysol, and bacillol in the same dilution, requiring 15 minutes' contact to kill pus cocci, whereas none of the others failed to do so in the 5 per cent, solution in less than 5 minutes. Sulfonaphtol. — This is a coal-tar product of variable composition, widely employed in surgical practice and in general disinfection. One specimen tested by the author^ failed, in 5 per cent, dilution, to ster- ilize 2 typhoid stools and 2 typhoid cultures in 2 hours ; and another ^ in the same dilution required between 30 and 45 minutes to destroy Stajjhylococcus pyogenes aureus. 1 Archiv fiir Hygiene, XVIII., 1893, p. 35. 2Ibid. XYIII.,1893, p. 57. 3 Zeitschrift fiir Hygiene und Infectionskrankheiten, XV., 1893, p. 192. * Centralblatt fiir Bakteriologie, XII., 1892, p. 234. 5 Archiv fiir Hygiene, XIX., 1893, p. 347. 6 Ibid., XII., 1891, p. 359. 7 Ibid., XXI., 1894, p. 198. * .Journal of the Boston Society of Medical Sciences, March, 1899. ^ Annals of Surgery, October, 1904. ALCOHOL. 691 Alcohol. OnliiKuy ;i1(v»1k)1 Iimm lon^ Ix-cii used ,'ih a y^rnsorvativo of or^^'lnic inatcri.'ils and as a (lisiiifccfjiiit in .siir^rical yr-.u-Ucc. Its fJisiiifc-r-tant projMirticis were slii.'* per cent, alfoliol. Sonu! years after l<'iirl)rin;h against staphylococci the acli(»n was very hIow. Nijland,'"' experitnenting with a potash soap containing 47.2 per cent. of wat(!r and a hard so;i]) containing 1 ^.5 per cent., found (hat the former in 0.2 1 per cent, sohilion kill(Ml cholera haciteria in 10 minutes, and the latter in the sam<' str(Migth was not wholly elfective in 1 o^ f)nt in {)..'}0 ])er cent, solution dcsstroyiid th(;ni within I mimile. 'J'he cholera organism was used by Jollcs" in testing iive soaj)s, all of which proved to he in(>fTicient. By 10 per c(mt. solutions, th(! bacteria were destroyed within 1 minute; by 4 j)er cent, in 10 minutes; by 2 \)vt cent., and in three instances by 1 per cent., in .'JO minutS'. p. albus in a minute. From all the evidence, conflicting though it be in certain respects, it must be evident that in soap we have an agent which, with all its limi- tations, is entitled to very serious consideration, at least as an auxiliary in complete disinfection. Medicated Soaps. — In order to increase the disinfectant properties of ordinary soaps, various agents, including mercury compounds, car- bolic acid, and the cresol preparations, are incorporated in them. Com- pared with ordinary soaps, these preparations appear to be of doubtful utility, although in the hands of some experimenters they have yielded 1 Deutsche medicinishe Wochensclinft, June 15, 1899. SOAI'S. 'i'M ^()()(1 rcsiills. Vnnu ;iii cxtcii-ivc invest i^utioii <»(' llifw; ho;i|)H, SyriicH ' concJiidcd lJi;ii, foi' ;ill |»r;icli<',il |)iir|)()scs, imm.-( oC llicrii pdSHChH no ii(l(I(!(l vmIik', I)|iI. Ili.it III'' MMTciiry hom^s arc ii-cCnl in (li-infl-<-tion of tlid li:uis ctrntaining cor- rosive sublimates and other disinfectants, because new compouuds ai'e ^ Bristol Medico-Chirurgical Journal, Sept., 1S99. '^ Loc. cit. 3 Disinfection and Disinfectants, London, 1898, p. 485. < ]\Iedioal News, April 17, 1897, p. 4S5. s Zeitsohrift fiir Hygiene, ^'II., 1889. \\ o'21. ^ Loc. cit. ^ Gazetta degli ospedali e delle cliniche, 1900, ^o. 6. 598 DISINFECTANTS AND DISINFECTION. formed with the ordinary coustitueuts of the soap, and the natural disinfeetaut properties of the same are thereby diminished. Lysoform is a liquid perfumed soap, containing about 8 per cent, of formaldehyde, miscible with water and alcohol, and somewhat expen- sive. AVhile it has a marked deodorant action, by virtue of its formal- dehyde content, its bactericidal effect is decidedly slow. Symanski ^ found that a 2 per cent, solution required 5 hours' contact to destroy staphylococci in pus ; but Scydewitz,- working with pure cultures of staphylococci, streptococci, B. typhosu.'i, B. coli, B. dipldlierkc, and other bacteria, found that a 3 per cent, solution killed them in less than 3 minutes, and a 4 per cent, solution required but 1 minute. Anthrax spores were killed by a 5 per cent, solution in 4 hours. On the other hand, Galli-Valerio ^ found that a 5 per cent, solution required 4 hours' contact to destroy Staphylococcus pyogenes aureus, and a 3 per cent, solution was ineffective against B. coli in less than 45 minutes. It is asserted and denied that it is non-irritant to the skin and mucous mem- branes. Weyl '^ asserts that it is poisonous, even in small doses, and that to the gastric mucous membrane it is corrosive. Paralysol is a solid cresol soap, said by JNieter ^ to be able to destroy, in 3 per cent, solution, staphylococci in less than 1 minute, and in 1 per cent, solution, streptococci and B. typhosus in less than 2 minutes, and B. pyocyaneus, B. diphtherice, and Sp. cJiolerce Asiaticce within 3 minutes. Metakaline, a compound of hard soap and potassium metacresolate, is said by Wesenberg ^ to possess such germicidal power that a 0. 5 per cent, solution will destroy the common pathogenic bacteria within a few minutes. In the disinfection of hands by means of medicated soaps it should be borne in mind that the added disinfectant is commonly present in in- sufficient amounts, and that, as used, the soaps form a very weak solu- tion, which, in the time ordinarily given, can have but little, if any, effect. Formaldehyde. The germicidal properties of formaldehyde, otherwise known as methyl aldehyde and oxymethylen, the simplest known compound of carbon, hydrogen, and oxygen, were not recognized until 1886, and were not put to practical use until 1891. Formaldehyde is a gaseous product of oxidation of wood alcohol, made most simply by passing a current of the alcohol vapor over platinum sponge previously heated ; as the vapor comes in contact with the incandescent platinum, it is oxidized to aldehyde and water. (CH^OH + O = CHp + HjO). The continuous current maintains the incandescence. On a large scale, it is produced by treating the alcohol in copper tubes containing incan- descent coke. ' Zeitschrift fiir Hygiene und Infectionskrankheiten, XXXVII., 1901, p. 393. '-' Centralblatl fur Bakteriologie, etc., I Abt., XXXII., 1902, Orig., No. 3, p. 222. 3Therapeutisclie Monatshefte, XVII., 1903, p. 452. * Miinchener medizinische Wochenschrift, 1905, No. 27. ^ Hygienische Rundschau, April 15, 1907, p. 451. « Centralblatt fur Bakteriologie, Abt. I., XXXVIII., No. 5, p. 612. FORMA iJ)/':in'nh\ 699 ForiMJildcliydc is .soliiMc in w.ilcr ii|i to 10 |)cr cciif ., ;iii(| (rivets a IKilltrul Kollll.ioii, Itiil llii' (•oiiiiiicici.il |ii ( |);ii;i(ioii- ;iic ii-ii;illy KlJj^Jitly aciid in rvnvi'iow (Vdin liviccsoC (oiinif ;ni(|. Ii i-olniion cannot Im; H(,r()n^((r llian '10 per cent., and iiltcnipis to cone* iil rale il or fo condonfiff tli(! vapor (',ans(! il. to polynici'i/c lo a wliilc indi>linctly rry.-tallinr- holid, trioxymdliylcn or paiafoi iniddrliydc (( ';(n,;0.,j, wliicli is almost inw)lu- l)ls, and coinhines with nearly all fonl-snuilling j)rodncts of (h-com- position, forming odorless compoinids, thus acting as a deodorant. It transforms gelatin in solution to a tough transparent substance in- soluble in boiling water, causes blood serum to lose its coagidability by heat, combines with the ])roto))lasm of bacteria, and converts egg albu- min into a substance insoluble in water and indigcstilile. A\'ith am- monia, it forms an inert compound, hexamethylentetramin, which has the odor of neither substance (4NH3 -f- GCHp = (CH2)6N^ -f 6H,0). It has no action on copjK-r, brass, zinc, nic^kcl, silver, iron, steel, or other metallic substanc(>s, causes no diminuti(»n in the tensile strength of fal)rics, and has no bleaching or other effect on colors, excepting to intensify the effect of certain of the coal-tar dyes (fuchsin, saflrauin, and perhaps others). It may, however, fix blood, pus, and fgecal stains on clothing. It has no injurious action on clothing and other woven fabrics, furs, articles of rubber, leather, and paper, pliotographs, paint- ings, woodwork, and furniture. The antiseptic properties of formaldehyde were noteer cent, solution, commonly known by the commercial name Formalin, or from the solid polymer trioxymethylen, otherwise known as paraformal- dehyde and by the trade name Paraform. In some processes of disin- fection and deodorization, it is applied directly in the form of aqueous solution. Methods of Use, and Apparatus. — At first the gas was generated directly from methyl alcohol by means of lamps specially constructed for the purpose. The first of these was devised by Trillat, who was followed by Gambier, Barthel, Dieudonne, Krell, Tolleus, Robinson, ^ Journal fiir praktisohe Chemie, XXXIII.. p. 221. ^ Comptes rendus, CXIY., p. 127S. 600 DISINFECTANTS AND DISINFECTION. and others, Avbo presented various modifications and improvements, but all of the lamps thus far devised are open to several objections, among which may be mentioned the fact that a large, if not the greater, part of the alcohol is converted to carbon monoxide and dioxide, and the possibility of fire. Trillat, recognizing the defects of his own and other lamps, and being convinced of tiie futility of attempting to disengage the gas by evap- orating the aqueous solution from open vessels, whereby polymerization is caused, attempted to devise an apparatus in which the aqueous solu- tion could be employed without the occurrence of this undesirable phenomenon. The outcome of his study was the autoclave which bears his name. Fig. 97. Fig. 98. Trillat's autoclave. Sauitary Construction Company's regenerator. Trillat's autoclave, shown in Fig. 97, consists of a cylindrical silver- lined pot of heavy copper, of about a gallon capacity, with a cover rest- ing on a rubber gasket and secured by means of turn-buckles. The cover carries a pressure gauge, a thermometer, and an outlet controlled by a valve and terminating in a narrow brass tube. The pot is sup- ported on a tripod, and beneath it is a Swedish lamp, the flame of which is fed by vapors from kerosene oil forced out by compressed air. In the pot is placed not more than three-fourths nor less than one- fourth of its capacity of a mixture of the 40 per cent, solution of FORMALI>i:iIYI)l':. OOl f()rm;il(l('hy(](! ;ui(l chloride of calfMiim, (If hiff'T for tlio j)nrf>oHf of ])rov('iil,iii}i; polviiicri/.-dioii iiihKt prcssinf. 'I liis niixfiin-, wliifli fori- tiiiiis 150 {j^nuiiM of tlic chloride to the liter, is known eh Formf)chlorol. 'V\u\ (oriiiMldcliydc soiiilioii iiHcd slionld he |)r;iflic,;dly fn-c from niflhyl .mIcoIioI, vvhifih, while of ii(» |)r;iclic;d iiitcrcsf, under ordinary eireiim- HliiiKtes, Ih ail oI))eelioiial)le iiiipiirily when fli<" solution is lu-aled nnder ))i'(!ssnre, since \\\v\\ if. nniles with a eorresponrjin^ arnonnl of fr»rnial- (lohyde io form inert metli\ l;il. The cover is (irndy fixed hv the tnrn- l)nc.I:e of simplicity and economy of time, for when the apparatus is placed in jwsition with its lamp burninij, it requires no further atten- tion on the part of the operator, who then, Avith other lamps, is enabled to start the process elsewhere, and thus accomplish much more than Fig. 102. Vertical soot ion of Breslau regenerator. (Lamp in position.) another Nvho, operating an autoclave, or similar apparatus, is obligee! to give it constant attention as long as the gas is being generated. Still another apparatus is that used in what is known as the " Bres- 604 DISINFECTANTS AND DISINFECTION. lau method," in which the gas is disengaged in company with an abundance of steam, by boiling dikite formaldehyde solution. The apparatus shown in Figs. 101 and 102, taken from the description of the method by von Brunn,i consists of a copper boiler about 14 inches in diauieter and 3 in depth at the periphery, with an immovable cover slightly domed, in the centre of which is an outlet tube, to which a stout rubber tube can be attached. The cover is provided also with two handles and an orifice closed by a screw cap. A flange around the upper border of the boiler keeps the latter in place when it is put on its support, which is a cylinder of enameled sheet iron about 14 inches in height, provided in its loAver half with slits for the free en- trance of air, and on its iuner side with three supports for an alcohol lamp. The lamp is an open dish, through the bottom of which, in two concentric rings, 20 tubes project upward as high as the sides of the vessel. With this apparatus, 3.5 liters (nearly 4 quarts) of fluid can be brought to boil in 10 minutes, and nearly the whole can be evapo- rated in an hour. The amount of alcohol placed in the lamp should be about one-fourth of the volume of the solution in the boiler, and this will be consumed before the boiler is empty. Like the Sobering lamp, the apparatus may be left in the room or it may be used outside with a delivery tube passing through the keyhole. In order to achieve the best results, a dilution of 1 part of the 40 per cent, solution of formaldehyde with 4 of water is recommended. With this dilution, one avoids the polymerization observed when the undiluted solution is heated, which is due to the fact that the water is driven ofi' faster than the formaldehyde. A somewhat similar apparatus has been devised for the generation of steam in connection with the use of the Schering lamp. It consists essentially of a circular copper boiler, surrounding the Schering lamp and heated by a circular open alcohol lamp which is really a sort of gutter into which a measured amount of alcohol is poured. Various methods have been devised for spraying the solution of for- maldehyde itself, but they have had their day and have fallen into disuse. In many municipalities the public health authorities suspend, in the space to be disinfected, sheets wet with the requisite amount of for- malin, which is thus allowed to evaporate into the atmosphere. A method of generating the gas which does away with special appa- ratus and also the need of a flame is that of Evans and Ilussell,^ •which depends upon the fact that when formalin and potassium per- manganate are brought together, a violent reaction occurs, with the evolution of much heat and rapid liberation of the gas, and also vaporization of the water. Numerous experiments demonstrated that, for the attainment of the best results, 6.5 ounces of the permanganate in the form of powder or very small crystals should be employed with each pint of formalin. In any given case, the necessary amount of each having been determined, the permanganate is placed in a suitable 1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXX., p. 201. ^ Thirteenth Report of the State Board of Health of Maine, 1904, p. 234. FOIlMM.hlHIVni':. fJ05 V(!ss(^l ntul ilic forrnalin is pounid upon it. 'I'lic cvolulioii of tlu; ^;iH hciii^ Viwy Tiipid, it is iicrcssiiry for I lie op( i;ilor lo Ic.'ivf: the room ',in (jiiickly iiH |)OKsil)l('. ( )n .iccdiinf of llic frotliiiif^ uliirli occiirn in cuu- ,s{!(pi(!iK;(! of I.Ik! violence of the icaclJ**!) vwn into water, gives off formaldehyde gas with a ra])idity which varies accord- ing to the relative pro])ortioiis of the ingredients. Equal weights f»f the peroxides and paraformaldehyde mixed with twice their volume of water cause a violent explosion, but the preparation in the proportions presented gives off the gas very quickly without explosion. Selter^ reported that the action is so ra])id and the room is filled with the gas so quickly that the usual precautious of sealing minor apertures are unnecessary. Using as test-objects anthrax spores, staphylococci, and fresh tuberculous sputum, he reported favorable results, as did AVesen- berg,^ who used the same and additional test-objects. But Nieter^ dis- agrees with Selter as to the necessitv of sealins; the room, and while conceding the advantages of simplicity, freedom from danger of fire, and the possibility of a number of disinfections simultaneously under control of a single individual, jioints out a very material disadvantage in the high price of the compouud. Unfavorable results are reported by Ingcltinger," Bock,^ Kirehg-aesser and Hilgermann," Proskauer and Schneider,'-' and also by Christian ^^ and Hammer!. ^^ 1 Tlierapeutic Gazette, July, 1907. ' Zeitsi.'lirift iTu- aiigewandte Chemie, XIX., 1906. No. 3.S, p. 1412. 3 ^[ulu•l^ene^• niedizinische Woohenschrift, 1906, p. 24'2-5. 4 lIvLrienisohe Rnndscliau, Xovember 15, 1906, p. 1241. 5 Ibid., February 1, 1907. p. 151. 6 Klinisches Jahrbuch, XVIII., 1907, No. 1. 7 Ibid. 8 Ibid. 9 Ibid. 1'^ Ilygieni^olie Eundscliau, ^lay 15, 1907, p. 571. ^1 Munchener me<.Uzinisclie Woclienschrift, 1907, No. 23. 606 DISINFECTANTS AND DISINFECTION. Dieiidonne' advocates the evaporation of diluted formalin with the aid of heated bricks, the liquid being poured over them, or of red- hot steel bolts, weighing about 7 pounds, held in a sheet-iron pocket in the vessel in which the liquid is contained. A perforated cover is em})loyed to minimize the amount of loss of liquid by spurting. Another simple method of generating the gas and steam at the same time is that of Schering,- in which pastilles of paraform and unslaked lime are employed. These are wet with warm water, and the heat which is produced in tiie process of slaking the lime is sufficiently intense to cause the volatilization of formaldehyde from the paraform and the formation of steam at the same time. One may use also unslaked lime and diluted formalin, dropping the former into the latter. This process has the disadvantage that part of the formaldehyde released is decomposed. To avoid this the addition of oxalic acid or of sul- phuric acid is proposed, but the process is patented. Another method of generating the gas consists in the application of formalin to unslaked lime, the heat produced thereby liberating the gas with considerable rapidity. An improvement upon this method is offered by Huber and Bickel,^ who report very satisfactory results with a mixture of about 2 quarts of formalin, 4 pounds of quicklime, and about 6 quarts of boiling water for each 1000 cubic feet of air space. The lime is placed in a large wash-tub, the water is poured over it, and then the formalin is added. The gas and generous volumes of steam are given off very rapidly, and the space to be disinfected is soon filled with the vapors. The method of Elb, with "carboformal Gliihblocks," yields results which do not warrant commendation. Germicidal Properties. — The first to note the antiseptic effect of formaldehyde were Loew and Fischer in 1886, but although Loew continued his ol)servations for some months, and Buchner and Segall made a study of its antiseptic action in 1889, Trillat, in 1892, was the first to draw attention to the importance of the agent as a disinfectant. Almost at the same time came a publication by Aronson,* and since then the germicidal properties of this substance have been the subject of more numerous investigations than have been made of those of all other disinfectants combined. So many have been the favorable reports and so well has been established its claim to first place as a gaseous dis- infectant that it is hardly necessary to present the evidence in detail. It is sufficient to state that, provided the gas can reach them in suf- ficient concentration under favorable conditions of temperature and moisture and with a reasonable period of contact, no pathogenic organ- isms can withstand its influence. Although certain experimenters have claimed for formaldehyde a much greater penetrating power than can be explained by any law of 1 Die arztliche Praxis, 1901, No. 2. 2 Hygienische Rundschau, 1900, p. 708. 3 Miinchener medizinische Wochenschrift, September 3, 1907. 4 Berliner klinische Wochenschrift, 1892, No. 30. F(HiMM.i>i:iiYi>i<:. 607 pliysi(!S, ii is v(!ry ^cncrully ;i^n'C(l lliat, in tlu' ^'aHfoiiK form it i.'- rucn-iy ii siirlac,*! (lisiiifiM-fjuil, unless I lie olijc*-! cxposr-fl is casilv pr-rnKiiMr- hy any gas or inixtiici' of" ^.'i^e,-, siidi ;i- :\\r. W'liilr il '•;iiiii of elieese-cjotli ; and, altliou^li it may he ahle to sleriliz(! test-ohjects placed inside a pillr»\v or inattr*-"- the (!overin|^ of which is laid o|)en, it cannot ordinarily ix- depen-|)iifijrfi wlioiild l)(! r(i(^('ivcf' lime and clilorinaUid lime are also eHifMetit. (V)rrosive siihliiiiati! i.s very nneerbiin. V>y r(!a,soii (»r its eonsislciHn' and adhesive properties, s|)iitiim is one f»f' the most diniciih. iiialcrials to sterilize It is es|)eeially dan^rcroiis, as it may eoiitaiii iar^-e immhers of eiitaiif^led hiieteria, wliieh, on flryin^, mjiy be disseminated hy air enrrents. Discharges from Mouth, etc. — In diphtiieria and jjertuHsis, all dis('ha-rii:;es (Voin the month and throat should he reeeiv(!d r)n piee^-.s of rag, which should he hmned. The di|)htheria organism retainH its vitality a, long time in the dry state, and .so may exist in the air of the room, if particles of false mciinbrant^ whifth ha|)pen to i)e thrown ont in coughing or sneezing are allowed to dry on walls, fnr- nitnn^, and elsewhci'e. Eating Utensils, etc. — All eating ntcnsils u.scd by patients with pneumonia, diphtheria, pertussis, the exanthemata, and tuberculosi.s should be well scalded. All napkins should be treated in tlir* same manner as infected bed-linen. All remains of meals should be de- stroyed. Bed-linen and Clothing. — In any case of sickness in which isola- tion is advisable or in which the morbific agent is known to exist in the bowel ilischarges, all used body-linen, bed-linen, towels, napkins, wash-cloths, handkerchiefs, etc., even if not obviously soiled, should be immersed for an hour in disinfectant solutions, and then conveyed under cover to the laundry or other suitable place, and boiled for an hour. Should the organism survive the first treatment, which event with proper care is unlikely, it will perish in the second. Should there be no focal or other stains, the boiling may be carried out without the preliminary soaking ; but in no case should the articles in a dr^- state be removed from the room except under cover or wrapped in a sheet wetted with an efficient disinfectant. In scarlet fever, for example, the morbific agent, whatever it may be, is exceedingly tenacious of life, and resides in the fine particles of epidermis wdiich are continually cast off by the skin, and it is easily conceivable that an armful of linen from a case of this disease might shed, in its journey to the laundry, a number of dust particles capable of nuich mischief. Neither lime nor chlorinated lime may be used on clothing, on account of probable injury. Corrosive sublimate 1 : 1 ,000, phenols and cresols in 5 per cent, solution, and formalin in 4 or 5 per cent, solutiou, may be advised. Colored goods are sometime? aflfected by some of the cresol compounds, but to no greater extent than may be caused by ordinary laundry soap. Hands. — In the nursing of cases of infectious disease, the soiKng and infection of the hands are frequently unavoidable. After every use of the bed-pan, every wiping away of discharges, every handling 612 DISINFECTANTS AND DISINFECTION. of the patient's body, aud, in short, after every act by which the hands may become infected, they shoukl be washed immediately and thoroughly, although not necessarily with that thoroughness which is so essential in surgical practice. Ordinary soap-and-water treatment should be supplemented by the application of some more power! ul disinfectant. Carbolic acid and the cresols may serve, but they leave a disagreeable smell, and have sometimes an unpleasant eflPect on the skin. Formaldehyde in 3 per cent, solution is efficient, but when applied frequently, causes a hardening of the epidermis M'hich is far from agreeable. Corrosive sublimate 1 : 1000 is not so efficient, and its use is often followed by dermatitis. Schenk and Zaufal ^ recommend the use of sand soap followed by immersion in corrosive sublimate 1 : 1000, as hot as the hands can bear. Air. — All attempts to disinfect the air of the sick-room in the presence of the patient are futile, for the presence of sufficient of any chemical disinfectant to have any effect on the bacteria present would cause the air to be irrespirable. It is a common practice to place about the room dishes containing carbolic acid, permanganate solution, chlorinated lime, iodine, and other agents, and to suspend sheets wrung out in all kinds of active and inert solutions, in the vain hope that thereby the air is made better for the patient and incapable of trans- ferring infection to others. Whether the agent used is a true disin- fectant in any strength ^vhatever, and whether the sheet is continuously or only intermittently wet, do not appear to enter in any way into the question of efficiency. Ordinarily, anything sold in the shops at a high price and under a label alleging not infrequently the impossible, will be accepted without question. But it may safely be asserted that no disinfectant known can be of the slightest service when used in this way, and if this is true of the disinfectant, it must be of the sheet. Much can be done to remove the well-known disagreeable sick-room smell, due to the excreta and to matters eliminated by the lungs and skin, but all hope of producing sterility of the air should be aban- doned. If pathogenic organisms are present in the air, a much easier and more reasonable method of dealing with them is that of thorough aeration, and this is one of the most important parts of treatment in general. The germicidal properties of sunlight should also not be overlooked when it is possible to make use of this important aid. If good ventilation is not sufficient to keep the air sweet, the old-fashioned pastilles, containing benzoin, may be employed as occasion demands, or one or two paraform pastilles may be volatilized slowly in a small lamp for the purpose. In very small amounts in the air, the gas is in no way disagreeable or irritating, and acts very powerfully as a de- odorant, not by supplanting the smell, but by destroying it by chemical union. Room Disinfection. — Net until the termination of the disease or the removal of tlie patient should the disinfection of the sick-room and its contents be attemptod. This is not such an easy matter as is com- ' Miinchener medicinisclie Wochenschrift, April 10, 1900. f>nA (ITfdA L l>ISTNFK(;TIf>N. C 1 ."> monly Ixil'uivcd, uikJ miicli Hiij)|>*).sr;(l (liHiiir(;c(,i(»n is, l>y rcahon of a lack (»r Mioroiijz^liiKiSs, no \h'\,{v.v lliaii iioiio at all, or, iiir (!(',nt. of the |)athoii;eni to within very recent years are not^>ri- ously inadecpiatc!, and tlu! far superior processes in use to-day may yet be made more |)erfeet. IFoiisc' disinfection is often most insidli('ir;nt, even when wliat has been ;ard to the f"a(!t that all the connectinp^ rooms, hallways, and distant parts of the house may havidcrmal scales floatin^^ in the air, nor are these attracted to and retained by tlie interj)r>seove the threshold. Infective material may be carried in one way and another by members of the family, visitors, attendants, and even by the patient himself, to various parts of the house, and the room in which he has lain ill may, by reason of proper attention, lie the least in- fected one in the house, but yet in ordinary practice it is the only one treated. Probably oftener than not, much more than one room, and io not a small proportion of cases, the Avhole house, should receive atten- tion. The existing methods of room disinfection comprise mechanical treatment, direct appliaition of disinfectant solutions as spray or washes, liberation of gaseous agents, and combinations of all three. The bread process, devised by Esmarch,^ consists in rubbing the walls with pieces of bread, to which bacteria adhere with great tenacity. This is not applicable to rough walls, and when thoroughly and prop- erly done, involves such an amount of labor and material as to be ex- ceedingly expensive. The bread pieces, together with all crumbs which break oif and fall to the floor, are carefully removed and de- stroyed by lire. For the rest of the room and its contents, other proc- esses are necessary, including scrubbing with soft soap and water, wiping with disinfectants, and transportation of certain articles of clothing, furniture, bedding, etc., to the public disinfecting station to be treated by steam. The method of tre;itinp- walls, floors, furniture, and clothing bv 1 Zeitschrift fiir ITvffienc and Tnfectionskraukheiten, XXIX., 1S9S, p. 276. '' Zeitschnlt fur Hygiene, II., 1SS7, p. 491. 614 DISINFECTANTS AND DISINFECTION. spraying with solutions of mercuric chloride and other agents com- mends itself in some quarters and not in others. According to Rideal, 35,000 houses in Paris were disinfected by means of sublimate spray, 1 : 1000, in 1893, and a still larger number in 1894 with satisfactory results and with no bad effects from the poison. It appears, however, according to later evidence,^ that a number of the employes of the dis- infecting scj[uad have shown symptoms of mercurial poisoning, and liideal mentions cases of salivation in India attributed to corrosive sublimate wash for floors. The spraying process, whether satisfactory or not, and whether dangerous to health or not, is not quick, and requires other ti'eatment which consumes time and adds to the expense. The ideal disinfectant would be a gas with no destructive or harm- ful action on anything but micro-organisms, capable of penetrat- ing materials by which they are hidden, and acting with great quick- ness. Such an agent, it is safe to say, will never be discovered, for, even though the other requirements may be met, it is improbable that the physical law governing difiiision will ever be modified by any gas as yet undiscovered. Gaseous disinfection must ever be superficial or nearly so, and should be assisted by other methods to bring about the best results. Gaseous disinfectants which exert any injurious influence on the objects treated cannot be tolerated, and it happens that this class, which includes chlorine and sulphur dioxide, has been found wanting in efficiency. Formaldehyde gas approaches more nearly the requirements of the ideal disinfectant than any thus far tried, and has supplanted all others. In its application, no matter how it is generated, whether from for- malin or paraform, it is essential that every obstacle possible shall be interposed against its escape from the space under treatment, and that all objects within that space shall be so disposed as to present as much of their surface as possible to its action ; and even then, absolute perfection of results cannot be attained. Fliigge ^ relates that twice he prepared a small room, containing but little furniture, by placing patho- genic organisms on marked locations, and had the local disinfecting squad perform their office under careful supervision, and in both in- stances found that a fair percentage of the bacteria escaped destruction. He suggests, with good reason, that, in routine practice, the results must ordinarily be far less favorable. For the attainment of the best results, the various articles of furni- ture should be moved away from the walls, all articles of clothing, blankets, and other textiles should be suspended freely on lines or clothes-horses, the pockets of clothing turned inside out, and all cracks and other outlets carefully stopped with wet cotton, putty, adhesive paper, or other suitable material. Particular attention should be paid to the complete closure of all inlet and outlet registers j those in the walls should be pasted over with stout paper, and those in the floor should be so treated or covered with thick cloth wrung out in sublimate solution or diluted formalin. 1 Journal of State Medicine, IV., 189G, p. 146. ^ Loc. cit. PRA crrrM l disinfection. 1 5 Loosdly fii.tiii};' wiiidow-sMslics \\\:w ln' mi;i(Ic ti^lit !>)' nic'iriH u\' \vot)fJcn W(! of the keyhole of the door is necessarily (ieferrcd until tlie f>;eneration of the gas is c()ni])leted. The room is then loft uiiopenefl over night or, if the process is hegiin in the morning, through the day. On the expiration of the required time, ammonia in the nowissjiry amount is vaporized tln'ough th(> keylK)le, or tlie room is ontorem one point to another, dilferiiifjj |)erhaps very widely in climatir-, and other conditions, under orders which they may not ])resume to cjuestion ; their hours for sleep, meals, \vork, and recreation are fixed for them without consultation with them, and without regard to individual or communal preference. Since the s^overnmcnt necessarily deprives the soldier of his indepen- dence of action, it is bound by every principle of fairness to him to look after bis health and comfort, to promote contentment, and to waixl off ennui by all reasonable and proper means. Thus, the care of troops is a double oblig-atiou ; the men have every right to expect it, and the efficiiency of the army is dependent upon it. But no matter how care- ful the sanitary administration, it is a matter of common knowledge that in all wars, excepting the Franco-Prussian, and in that only with regard to the Germans, the mortality from disease has been far in ex- cess of that from casualties, and in all armies, more discharges are due to sickness than to injui'ies. The responsibility for the care of troops and health of camps is placed upon the medical officers, who have no power to com- mand and are hampered by being subordinate to laymen having often no adequate appreciation of matters purely medical. They have only advisory functions, and must be most careful in recom- mending changes to the very conservative military mind, which finds in long continuance of a condition the strongest argument for its longer retention, and is prone to look upon recommendations for sweeping changes as evidence of whimsical disposition and deficient training in sanitary science. Nevertheless, the medical officer has a very heavy responsibility placed upon him, and must advise his lay superiors and explain the im]iortance of the princi]>les underlying sanitary practice. He must make ]iroper recommendations for the protection of health of the troops in war and in peace, in camps and in garrison. 617 618 MILITARY HYGIENE. Since the efficiency of a military body is so largely dependent upon the health of the units of which it is composed, the result of a campaign may be largely influenced by the adoption or rejection by the commanding officer of the recommendations of his medical adviser. Unfortunately, if, by reason of physical un- fitness of the troops, a moyement fails or an epidemic of disease occurs, the public c\t once places the blame upon the medical depart- ment, and especially upon the head thereof, the Surgeon-General, and demands a reorganization, a sifting out of incompetent material, and especially, a change in the head, quite regardless of the possible fact that the choice of an unsanitary camping place may have been made against the judgment and advice of the medical branch, that the com- missary department may have been largely to blame, or that other influences quite beyond the control of the medical corps may have been at lault. The medical officer, both at home and in most countries abroad, has much ^vith which to contend. The corps is, as a rule, not sufficiently large for the body for which it is to care, but is expected to perform an amount of work and assume a responsibility which would fairly tax the capacity of one of double size. In an emergency requiring large additional levies and consequent employment of civilian physicians untrained in military life, the responsibility becomes proportionately greater. The recent experiences of this country and of England, when the outbreak of war necessitated the assembling and transportation of large armies, serve very well as illustrations. With us, on the break- ing out of war with Spain, a standing army of 25,000 was suddenly increased by enlargement of the regular service and enrollment of vol- unteers to ten times that size, but the small body of trained military surgeons, too small before, could hardly have been expected to be equal to the demands of the new army, even with the assistance of the physicians from civil life, who, although doubtless highly efficient in civil practice, were for the most part inexperienced in camp hygiene. The difficulties of sanitary administration were very largely increased by the recldessncss and ignorance of the volunteers in personal hygiene and general sanitation. The results were what might be expected, and are too well known to need further mention. The blame for all the disastrous experience was placed at once upon the medical department, which had luit little to say in the choice of camps, and nothing what- ever to do with the inadequate means of transportation and other factors in the production of a large mortality from disease. The experience of the English in the war in South Africa was essentially the same, and was due to the same causes. In the large standing armies on the Continent, a diffisrent order of things obtains. The officers of the line are more inclined to defer to the opinions and advice of the medical staff in matters requiring expert sanitary knowledge, and the authorities demonstrate a much higher appreciation of the value of an adequate medical service. As an 77//'; lll'JUHJIT. 019 illiistr.'itioii of" llic (liU'crcnrc in ili(! imh'v'\\\\£ of Mirli irinttirH in ('ti:r- nijuiy iuid rjnjj;l;in(l, IIk; following is cited : 'V\\(\ Jirilisli (irsl, inriiiilry flivision nnd (irst ciivalry liri^iidc, wifli two batteries of (ield nilillery, ;i eoni|);iny (tC rmj.dneepH, tel(;gra|)li (!()rj)H, railway eoiii|»;niy, niiiinniiilion corps, and lio,~|)it;d eorpH, onJerod to Sontli ACriea in tlie antinnn of I .SIMJ, and llie (ierniaii exjx'ditionary (5or|)S, eonsislinjr of two brij^jules of" infantry, three .sfjuadrons of chiv- alry, l"onr batteries of n0) |)(>iiii(ls. Vnr tlic inoiiiil.iln Iciflcric- iIm- li«'i;;lit rnusl, he nol, less lli:iii live (rd- ('ijrlil iiwlx-. "A v;ifi;ii ion nutcxrccdiiiir a (V;ict ion olnn inch ulKtvc llic rnaxilniirn luii<;li(. f^ivcn (<»r c'lNiiIrN' ;iii|)(;arritish Registrar-General, and by I)r, JJalfour, who showed that, in 1S8.'>, the army in India contained 41 })er cent, of soldiers under 25 years of age, and that among this con- tingent the death-rate from this disease was 4.34 per tliousand, while that of the men of 25 to 29 years was but 1.50 per thousand. Jn newly-arrived ivgiments, nearly half of the total death-rate was from this disease. Aitkcn gives a number of instances of the influence of youth and short residence on the prevalence of this fever. At one station, for example, out of 44 cases, 35 occurred in one; regiment com- posed principally of young soldiers, and 33 among men of less than one year's residence in India. In 1883, in India, 36.55 per cent, of those invalided home were under 25 years of age, and in 1884, 38.70, the principal diseases neces- sitating invaliding being anremia, debility, phthisis, he])atitis, and dis- eases of the heart and arteries. Throughout the Peninsular AVar, from 1805 to 1814, it was observed that the " corps Avhich arrived for service were always ineffective and sickly in proptirtion as they were made up of men who had recently joined the ranks," and it was calculated that 300 men having five years' experience were worth more than 1,000 newly-arrived, including the usual proportion of young recruits. Surgeon-General Sternberg, of the U. S. Army, in his annual report for 1885, shows that the greater proportion of sickness occurred among soldiers under 31 years of age, and that up to the age of 25, the rate was so much above the average foi" the whole army, that he questions whether their services had been a fiiir return for the cost of their luain- tenanee. In 1899, the British ]\Iedical Association passed a resolution requesting the Council to communicate to the AVar Office the opinion of the Section of INIedieine, that no soldier ought to serve in the tropics earlier than 22 years of age. In favor of the young recruit, Woodhull says that young men are more easily trained and moulded than older men, especially for the cavalry, and when well led, fight as well, as flir as mere courage goes. 1 On the Growth of the Kecruit ;uul Young Soldier, 2d Edition, London, 18S7, p. 58. 624 ' MILITARY HYGIENE. But as we cannot keep young soldiers several years in training, and as large bodies of troops can only be raised for sudden war, men not absolutely mature must be rejected. Ijord AVolseley prefers young men, and says : ^ " Give me young men : they do what they are bid, and they go where they are told ; they become more amenable to discipline, and though when you catch them first they may have some difficulty in carrying their knapsacks, once they get beyond that they are in a fit condition to take the field." If young men are enlisted, the work should be suited to their strength, and it should be kept in mind that they are still in the grow- ing and developing stage, and should have no greater amount of physical exercise than is suited to their condition. In other words, their work should be proportioned to their growth, and in two years they will, perhaps, have developed into valuable soldiers. Taken between the ages of 18 and 20, and drilled and trained with due regard to his immaturity and limit of endurance, the recruit often shows great progress in general development within the first half-year, particularly if, before enlistment, he was poorly fed, clothed, and housed, and engaged in an indoor occupation. His work should be moderate in the beginning and only gradually increased, since changes for the better in the human body cannot be brought about suddenly like those for the worse, induced by attempting to do too much at the outset. Since his lungs, heart, and blood-vessels are not yet fully developed, he can neither go through the manual nor cover ground like the seasoned soldier. The heart is called upon by the new and unaccustomed exercise to contract at a greater rate than had been its habit, and he soon becomes "winded." When this stage is reached, and he begins to feel or show distress, he should be allowed and encouraged to rest until the throbbing of the heart and the swelling of the blood-vessels sul^side and permit his lungs to resume easy breathing ; otherwise, he is more than likely to break down sooner or later. AVith properly regulated exercise and good food, he ought soon to show gain and not loss in weight. Should progressive loss be observed, it is a question whether he is likely to become an efficient soldier, and he should forth- with be referred for medical examination. Under the regulations of the British army, all recruits are kept under medical observation during the first three months of service, during which time, in addition to the ordinary drill, they have an hour of gymnastic exercise daily, under the supervision of a medical man ; and if, during this period, a man shows unfavorable indications, he is examined by a medical board. Should this body conclude that he will not ultimately develop into an efficient soldier, he is at once discharged on that ground. ^Military organizations composed exclusively of very tall men of imposing appearance are intended for display, and not for the usual work of the soldier, and, indeed, have often proved to be lacking in the essentials of good soldiers, unless they are unusually well propor- tioned. The superiority of additional height is commonly found to lie * Quoted b^' Aitken. Loc. cit. 77/ a; iiF.cnniT. 625 in tlic 1(!^ ;in(l neck, ;iii(l wIkii (cft .'! iii'ln- is exceeded, the iii- clividuul, ;iH !i, rule, is not, projtoilioiiMlely descloixd in the chc«t and niii,seul;ir syslcni. Siieii men are said to he more jtronc io di.seahCH in ^eiK'ral, and more es|)e('ially ('» pnlmoiiajy eomplaiiils, (lian rnen of mcidiiim li<'i^lil, and lliey beeomc; liiii^ned iriorc early on llu; niareli and nndei' all eirenmsianees vvlicrc, enduranee is of the first new.-hhity. Tlieir nHis('|('s are Ioniser, poHHCSS less fa.sei^-nli, and work lonfjor levcrH than those ol" tin- short men. "^riiey also oiler a hefler tar^'et for fhr- eiKMny. On the other hand, very short rcn'U an; ((iiitc as ohjeetionahle as their over-tall comrades. I)nrin<^ the (Jivil War, tlic Hniallest nx^n enlisted broke down, as a I'nle, after hnt a few weeks' service in the field. There are, of (bourse, exceptionally short men who are unu.siially ninscidar, hut, as a class, they are wanting;; in streiif^th. Examination of the Recruit. — The first step in the examination of a recruit is thorough washing with soa|» an!•' Till': SOLDfFJl. 027 flnicni f^roimd for njccliori. In 18f)H, in Imij^IuikJ, (>f' ()f>,o()] n.*crnit,H lor rcjriilnr H(;i'vic.(', I,7'I7, *»r tic-irly 1 in .''X, were rcjfcl<'(| dw ar-fount, of biul l;(!((ili nlonc ; \)\\\, IImh fi^nr(! ^iv(!H no in(li(;ii iuii , ])r('VciilM rnpid cooWw^r, "(* the hody wlifii it is in ;i cou- (lition of !i<'Xiv(! ncifspiciilion ;i('lcr |ili\.-Ic;il cxci'cisc. Jl \~ \\w more ]K;nn(!!il)l(!, iilsi), lo ;iii', wliidi il liold in I lie -|i:i(TH, lUid vvliicJi ndds io i(s properly fd" iion-coiidiict ion. IiiL;li(; vvocdicn nndcrciol liin^-, llici-cCorc, i- |»rc('cr:d)lc lo ii':irs f.xkik'Isi: and woiik. 633 itself ciimiot Ik; worn li;iltitii;illy or for ;i loiif^; titru', hocauw; of ite (rMiisiiiji; ^iciil (liscoinCoil lliroii^h rclciilioii of lirat jiiid )H'n-|»iralioii. li, is of iiiiicli more \:iliic in tlic form of a Maiikcl to f-jinad on \\\(: ^\'{)\\\\i\ (lian as ;iii ;iil idc of ch.lliin^. ('lolli niiiy Ix- niaric water- proof l)y allcnialc (li|)|iiiiL' inlo solntion.- of .-ihniiinntn hnljdiafe and soap, oi" by llioroiiali soaking in I'aw lin.-ccd oil nnd cxixisinf^ to tin; snii iinlil llioron<;lily rs on a long march, and the second for short movements ; hut either of these figures may represent exceedingly good work by the best of men in some climates and seasons and over some roads, or by raw recruits in their first marches over the best of roads. This is not for a moment to be looketl upon as evidence of the civilian's superiority over the soldier as a walker, for the two per- form the exercise under very different conditions. The civilian, in the first place, walks alone or with a companion or two, at his own gait and according to his ow^n will. He may vary his step and may rest at his pleasure ; he carries no greater burden than a walking stick, and may suit himself in the matter of dress and in the manner of wearing it. The soldier, on the contrary, is one of a large body proceeding somewhat stiffly at a pace set by one in command and not alterable at will. He carries his arms, accoutrements, and all his belongings, aud, perhaps, his rations for a number of days, and is hampered by straj^s and clothing which interfere with free circulation. He rests wlien ordered, may be halted, without resting, with annoying frequency, and may " march at eiise " only when, in the judgment of the commanding ofhcers, this is practicable. At one time, he is moving Avith exasperating slowaiess on account of obstacles ahead, and again, is hurrying to catch up with those gone before. iSIoreover, his marching ground is chosen for him, aud his miles are either throuijh dust or mud, for a soil so damp as to give off no dust is spee WOHK. fJ35 conHi(l(;r;il)I(! liurni ni:iy be induced by intfrfcnjiicc witli reHpinitioii and (■,ii'n hy j)Icss(M'c from I lie ncfcssary sJrapH iUTosH IIk- dx^t and nndcr the arni-pils. (Iiidcr (';i\(ii;ilil<' ciiciiniHianfjdH, IiIh irnpcditiicnbi, wiili tlic ('Xf inun- cles un(hdy. Th(! (J(!nnan irdiinliy soiihcr is more heavily e(|nip|»c(| tii;in liir- lirit- isli (>!• American, the total load exceeding'- 70 pounds, of which hi.s (slothing, e\(!hisiv(! oi' the heavy polished leather liemlet, accounts for n(!arly 24 pounds, and liis arms and e(|iii|)meiits, filled water-bottle, and cntrenchiufij tools nearly 4'i pounds, the i-emainder bein^ rations and sundries. His kit is carried in a leather knaj)sa(;k, around whif;h his rolled overcoat is fastened, and to the l)ack of which his c;imp ket- tle is strapped. Tlu; Russian soldier also carries more than 70 pounds ; the Italian, about the same ; the French, between 65 and 70^ and the Austrian, about (50 pounds. The blanket bag, which was substituted for the knapsack in our army in 1882 and abandoned after twenty years' use, is more oj)pressive than the blanket roll ; but the blanket roll is also oppressive, since, being carried across the body from one shoulder, with the ends tied together, it impedes -the raov^ements of the chest. Morever, its use involves a certain degree of inconvenience, since when the blanket itself is in use, the articles contained must be cared for in some other way. Other devices to take the place of blanket rolls and knapsacks are in use, and meet with difi'erent degrees of approval. The one most highly commended neither impedes respiration or circulation, nor in- volves contact with the back and consequent shutting out access of air. The weight is supported chiefly by the hips. With new levies, the first marches should not exceed a very few miles, the distance being increased gradually day by day, until they become w^ell seasoned, with occasional days, not including Sundays, set apart for rest and recreation. When thoroughly seasoned, there is less friction, and with greater experience, comes increased efficiency. It takes but a short time for new soldiers to learn not to attempt to ciirrv unnecessary articles, which, at first, they are iuvariably prone to look upon as essential to comfort and pleasure. Cavalry and infantry should march separately if possible, and in as open order as practicable, in order to avoid crowd-poisoning, which is a consequence not alone of indoor overcrowding, but also of close aggregation of men in the open air. If possible, marching by night and in the hottest part of the day should be avoided, for in hot weather the men are easily exhausted by exercise in the blazing sun, and since they can get no sleep during the day, they need the night hours for their proper rest. The early morn- ing hours are the best for marching, as for other forms of work, the 636 MILITARY HYGIENE. men being then at their best ; but unless absolutely necessary, their sleep should not be broken before the usual time, since what is thereby gained in distance is more than lost through the interruption of neces- sary sleep. Before starting, a light breakfast, including hot coifee, should l)e taken. During the first hour, the pace should be fairly slow, and when two miles have been covered, there should be a halt of at least a quarter of an hour, during which the men should attend to calls of nature and throw oif their loads and rest at full length. When the march is resumed, the distance to be covered may be lengthened by a half mile, and when this distance has been traversed, there should be another halt of about the same length as the first. After this, the rate may be increased to three miles per hour with a halt of ten minutes in each hour, and this rate is sufficiently fast, except for forced marches. The halt in the middle of the day for dinner should be of several hours' duration, so that the men may have a good rest, avoid heavy work directly after a hearty meal, and look after the condition of their feet. As it is unsafe to eat heartily or drink copiously while greatly fatigued or overheated, a reasonable interval should be allowed before dinner. Halts due to accidental circumstances are very trying to patience and strength, and when their probable duration can be determined, this should be communicated down the column, in order that, if the inter- val is to be of sufficiently long duration, the men may have the advantage of resting, rather than stand with their arras, losing patience and temper. Since, also, irregular rate of movement is fatiguing and annoying, minor obstacles, such as mud and water, should not be allowed to interfere with regular progress. Music of all kinds is very invigorating to marching men ; baud music, fife and drum, the drum alone, and singing. In the continental armies, singing is much encouraged, as it keeps up the spirits and gives a rhythm and swing to the march. If the weather is hot, men should be allowed to promote evapora- tion of perspiration by opening their coats or blouses ; otherwise, water is lost from the body without performing its function of reducing the body-heat. To avoid excessive thirst, a full drink of water should be taken before starting. The canteens should be filled with water or cold tea for use during the day ; but free drinking on the march is not to be advised, since it tends to beget constant thirst. The mouth should be kept closed as much as possible during the march, and the sensation of thirst can be controlled by holding a smooth pebble in the mouth or chewing a green leaf. Simple occasional moistening of the mouth is better than free and frequent drinking. In case of exhaustion by excessive loss of fluid by perspiration, drink- ing on the march is necessary ; but under the usual conditions, the can- teen should be used only at meals and near or at the end of the day's march. Another reason for abstaining as much as possible from drink- ing is the uncertainty of supply, for no dependence can be placed on THE SOU) flag's EXI'inaiSE AND WORK. 637 tliC! prohahilily of rcCilliii^ (Jic c.-uiU'cii (lining the duy'.s mur<:li. Il'ii''-, ciicli rniiii should conwirvc! his Hni)|)ly uh tlioii^h he wore wrfaiti that no rnon; is to Iw. Ii;i(l bcCorc Ihc day's dcsliiiaiion is reached. The :mioiirit carri(!d may he I<<'pl' (iiirly i-ool l»y \vr-a|)|)iii^ ihc caiit^cii in a \\<-l floth, the eva|)oration I'loni wliidi cmscs pcrecptihlc! h)\\('i-in^ of icrnpcratiin;. A litth! vinc<^ar or lime jnicc, if ohtainahh', added to the wuU-r, ^dvej* it a relish and helps to :dl;iy thirst. " In many jjarts oC end J)esert, .'>'> or 40 miles from water to water, is nsnally effected by making; a ni^rht march of 25 miles, when the troops o^o into camp to rest for a few lion rs before resnmin<>; their jonrney, and to have coffee issued from a \vater-snp|)ly carried in the wap;<)ns." (Smart.') On arrivin?: at a camping-place, the water supply should be innnediately {guarded to prevent ]K)llution and tramjilinp; of the margin. If the supply is small, the _i>;uard should be doubly efficient. If the sup])ly presented is a small and shallow stream, it may be well to make small reser- voirs by means of temporary dams, one for drinking-water fV»r the men, another below for the horses, and another for bathing and laundry purposes. Straggling should be prevented as much as possible, since it is a very serious evil to the morale and efficiency of the body as a whole. If strafffflina: becomes considerable, the column should be halted until the stragglers can overtidce it, else they will get no rest, since the hourly intervals for rest must be utilized by them in coming up, and the column is, ]icrhaps, already in motion again. Those claiming to be sick or unable to march should be examined by the medical officers, who will separate the really unfit from the malingerers ; the former are given careful transportation ; the latter, disposed of accord- ing to their deserts. At the end of a day's marching, the men should lie dismissed as soon as possible, and they should be careful to guard against becoming chilled through reckless removal of clothing, and should again look after the condition of their feet and persons. On long marches, an occasional day should be taken for complete rest and recuperation, otherwise an inevitable diminution in efficiency will be occasioned, Woodhull cites an interesting instance of overmarching in the Franco-Prussian War. The German Grarde-Corps, consisting of 30,000 infantry, left the Rhine on August 3d, lost less than 0,000 in action, and on September 2d, the day after Sedan, numberal 13,000 for duty. On September 19th, they reached Paris with but 9,000 men, 1 Buck's Hygiene and Public Health, New York, 1879, Vol. H., p. 119. 638 MILITARY HYGIENE. more than 11,000 having been broken down by exertion, little actual sickness having occurred. Care of the Feet on the March. — If good marchers make the best soldiers, it follows that the possession of the best soldiers is largely dependent upon the condition of the feet, and, therefore, it is incumbent on the line officers and medical corps to see that the individual men are properly, instructed in their care, and that they are faithful in per- formance. The footsore man, so far as efficiency is concerned, is a sick man and becomes the equivalent of baggage. He cannot march, and suffi?rs pain when at rest. Nearly all new men not accustomed to marching are likely to suffer from excoriations across the toes, on the insteps and malleoli, and on the back and sides of the heels. This is due to friction, and, if attended to at once, may be prevented from becoming serious. The application of strips of adhesive plaster of generous size to the affected parts will affbrd the same protection as is given by a leather glove to the hand engaged in any frictional work. Blisters should not be opened, except by a minute puncture at the edge ; after the fluid has oozed away, the spot should be protected with adhesive plaster. The extensive opening of a blister permits access of air to the sore area beneath, and the stimulation therefrom is very active and painful. Men should be instructed to trim their toenails square across and not too close. Before marching is begun, all men with any soreness of the feet should report themselves and be examined, and at the end of the day, if not before, they should be regularly inspected. Men unused to marching will often find greasing or soaping the feet and stockings an excellent prophylactic against soreness. A neutral grease like mutton- tallow is preferable to soap, since sometimes it happens that the latter assists the perspiration in macerating the cuticle. If the boots are made supple with grease, they tend less to cause soreness, and, in addi- tion, are rendered waterproof. An excellent plan for officers and others who can afford them, is to wear silk stockings under the ordinary socks, especially when the feet are naturally tender. The feet may be tough- ened by being soaked in warm strong solutions of alum or common salt. Zinc ointment, containing 5 per cent, of tannin, is also very useful. Salicylated talc (talc 87, starch 10, salicylic acid 3 parts by weight) is used in the German army both on the march and in garrison. It is sifted from a dredging-box into the shoes and over the feet. If the soreness is due to the stockings and not to the shoe, it is often advantageous to change them from one foot to the other, or to put them on inside out. Some of the continental armies use bandages in place of stockings, and some use neither, substituting therefor a liberal coating of grease. Soreness is due often to neglected bunions, corns, both hard and soft, and infleshed nails. These troubles need special treatment. In the British army, the authorities have caused a number of the non-commissioned officers to be instructed in chiropody, and the THE SOIjDIICH'S I'OOh; " RATfONS." 639 HUoccHs of" the (^xp(!rim(!rif, Ikih rn.'i(lir;ili<>ii imd dirt frf)rn hin feet by llioroiigJi waxh- '"K> [)ayin^' |)artienlar atlcnlion to th(! Hurfatces between tlir; toe.s, whr-re (excoriations and soft <'orns are prour to appear. I)iistinf^-[)owder or zine ointment on absorbent (vitton may l)e applied, if advisable, between the toes. Th(\ feet should be made (piite dry before the stockings are a^ain drawn on. If water eann(»t. be obt^iined in snflieient anirjiirit, wiping with a dry or moist, (-loth will be found to add rnat<'rially U) comfort, and is much to Ix; preferred to lon^ soakin^r^ which, by Hoft- ening the cuticle, assists the formation of blisters. At the eiifj of the day, the feet should be washed and the stockings changed ; thfjsc removed should be washed as soon as practicable and dried during the night. Care of Other Parts. — Not uncommonly, soldiers, especially raw recruits, arc much inconvenienced and annoyed by chafing at various points, particularly on the inside of the thighs and between the nates. This is promoted by pcrsj)iration and restrained by dusting-powder, zinc ointment, vaseline, and cleanliness. Wo<»dhul] advises against washing the face and neck in thv. morning while on the march, because the removal of the natural secretion makes the skin more susceptible to the influence of heat and dust. He recommends washing the eyes and mouth, and merely wi|)ing the face and neck with a damp clotTi, At night, the face, neck, and whole body should be washed, if possible ; but, foremost of all, the head, armpits, feet, and g(!nitids and adjacent parts. Care should be taken that the bowels are not neglected while on the march, any more than wdiile in garrison. If purgatives are required, those given should be mild in character, and not such as may require repeated operations at short intervals. The Soldier's Food; "Rations." The word " ration " is understood commonly to mean the amount of food issued to each soldier for a single meal. This, however, is far from being the truth. Under the regulations, " a ration is the allow- ance for sustenance of one person for one day, and consists of the meat, the bread, the vegetables, the coffee and sugar, the seasoning, and the soap and aindle components." Enlisted men and hospital matrons, and, when the circumstances of their service make it necessary*, civil- ians employed by the army, each draw one ration each day. The ration is not necessarily the diet, since parts of it may be exchanged for other things or for the cash equivalent with which to buy them. It is fixed by laAv, and can be changed only by legislative enactment. The different articles composing the ration for troops in garrison or in permanent camps, excepting in Alaska, and their amounts, are as follows : 640 MILITARY HYGIENE. Gakkison Kation.^ Component articles and quantities. Beef, fresh Flour Baking powder Beans .... Potatoes 2 , Prunes ' Coflfee, roasted and ground Sugar Milk,evaporated,unsweet- eued Vinegar Salt Pepper, black Cinnamon Lard Butter Syrup Flavoring extract, lemon 20 ounces . 18 ounces . .08 ounce 2.4 ounces 20 ounces . Substitutive articles and quantities. 1.28 ounces, 1.12 ounces 3.2 ounces . .5 ounce . .16 gill . . .64 ounce . .04 ounce . .014 ounce .64 ounce . .5 ounce . .32 gill . . .014 ounce f Mutton, fresh I Bacon ' Canned meat, when impracticable to I'uriiish fresh meat Hash, Corned beef, when impracticable to furnish fresh meat Fish, dried Fish, pickled Fish, canned Chicken or turkey, dressed, on national i holidays when practicable Soft bread Hard bread, to be ordered issued only when impracticable to use flour or soft bread [Corn meal JRice ( Hominy f Potatoes, canned I Onions, in lieu of an equal quantity of potatoes, but not exceeding 20 per I centum of total issue I Tomatoes, canned, in lieu of an equal quantity of potatoes, but not exceed- ! ing 20 per centum of total issue. Other fresh vegetables (not canned) when they can bo obtained in the vicinity or transported in a whole- some condition from a distance, in lieu of an equal quantity of potatoes, but not exceeding 30 per centum of [ total issue. f Apples, dried or evaporated .... I Peaches, dried or evaporated .... ■{ Jam, in lieu of an equal quantity of 1 prunes, but not exceeding 50 per [ centum of total issue. (Coffee, roasted, not ground -| Coflfee, green (Tea, black or green Pickles, cucumber, in lieu of an equal quantity of vinegar, but not exceed- ing 50 per centum of total issue. ( Cloves J Ginger . . . . (Nutmeg . . . . Oleomargarine Vanilla . . . . 20 ounces. 12 ounces. 16 ounces. 16 ounces. 14 ounces. 15 ounces. 16 ounces. 16 ounces. IS ounces. 16 ounces. 20 ounces. 1.6 ounces. 1.6 ounces. 15 ounces. 1.28 ounces. 128 ounces. 1.12 ounces. 1.4 ounces. .32 ounce. .014 ounce. .014 ounce. .014 ounce. .5 ounce. .014 ounce. ' In Alaska 16 ounces bacon or, when desired, 16 ounces salt pork, or 22 ounces salt beef 2 In Alaska the allowance of fresh vegetables will be 24 ounces instead of 20 ounces, or canned potatoes, 18 ounces instead of 15 ounces. ' At least 30 per centum of the issue to be prunes when practicable. Note. — Food for troops traveling on U. S. Army transports will be prepared from the articles of subsistence stores which compose the ration for troops in garrison, varied by the substitution of other articles of authorized subsistence stores, the total cost of the food consumed not to exceed 24 cents per man per day. The ration issued to troops in the field in active campaign is the same in amount, but is somewhat less elastic. Thus, the various forms of fish are eliminated, as also are peas and hominy, and when potatoes are not procurable locally the desiccated form is served. The fruit component consists of canned jam (1|- ounces). i221. General Orders No, 47,*War Department, Washington, April 3, 1908, Paragraph THE .SOLDI Kirs FOOD; "RATIONS." I'lKI.I) ItATION. Cdiiiixini'iil, arliclcH U)iroeiirable locally ,1n lieu of an ei)nul i|iiiintity of |it exceed- ing f)0 per centum of total issue. 20 oiin(u«. 10 ouncpends upon circumstances, and largely upon the discretion of company commanders guided by the advice of the medical officers, but, as said before, the actual food value is fixed by Congress, and is based on the experience and study of many years. Is the United States Ration Suited to the Tropics ? — The ques- tiou of the suitability of our ration to the tropics is one which has assumed great importance since the necessity arose for maintaining large armies iu our uew possessions, aud its discussion has been mai'ked by a much more temperate tone, and has, therefore, yielded better results. The beginning of the discussion may be said to have arisen from the fact that it became generally understood that bacon was a necessary 646 MILITARY HYGIENE. constituent of the daily food, both in caniji and in active operations, in- stead of an alternative, as may be gathered from the wording of the statute — fresh beef, or fresh mutton, etc., or pork, or bacon, or salt beef, or dried fish, or pickled fish, or fresli fish. Bacon lias its advan- tages at certain times, but is not eagerly sought after by those not in good health, nor is it acceptable in very hot climates as a regular diet any more than any other fatty food. Fats are much needed in cold climates for the production of heat ; in hot climates, the necessity for their use is but slight in comparison. But when fresh meat cannot be obtained either on the hoof or from cold storage, and when the appe- tite is cloyed by canned meats (and this is soon brought about), bacon is acceptable as an occasional substitute. To those at a distance and uniacquainted with local conditions, the ideal supply of fresh meat is cattle on the hoof. But the cattle of the tropics are not the same as those which we know, nor are they always to be had in even small numbers. Sending live cattle from home, to be driven along on the march to be killed as needed, is not always practicable, for even if landed in good condition, they cannot be kept on the march, and, unless the country traversed is good grazing land, they lose weight and die off rapidly. Canned meats are much inferior to fresh meats, and cannot long be eaten with relish. The canned so- called 7'oast beef is commonly the residue of meat after the extractives have been boiled out of it for the manufacture of meat extract, and it is, therefore, lacking in flavor, although not materially diminished in nutritive properties. It is often as tasteless and almost as difficult to chew as towelling, and is far from inviting in appearance, especially when the cans are opened at ordinary hot summer temperature. According to many experienced minds, the consumption of meat in any form should be much limited in the tropics. Koquemaure ' ad*^ises the European in the tropics to take nothing into his stomach, except articles easily digested ; mutton, beef, and pork only in moderation, and not too thoroughly cooked, and not regularly or too often ; birds, eggs, and fish are more to be commended ; especially to be relied upon are rice, dried vegetables, fresh vegetables, starchy foods, and ripe fruits in good condition. Kohlbriigge ^ places above all other influences in the deterioration of Europeans in the tropics the too extensive use of animal fats, which, he claims, are responsible for much of the diarrhoeal troubles of the tropics. He recommends the vegetable oils for supply- ing what fats are needed by the body. The observations of Dr. L. L. Seaman,^ in Porto Rico, lead, in part, to the same conclusion. He relates that, within a week after landing in the summer of 1898, in spite of the strictest sanitary precautions and personal hygiene, the entire force with which he was connected suffered from some form of intestinal catarrh from one cause and another, and that medication was of no avail, since the diet of bacon, ' Hygiene alimentaire aux pays chands, Bordeaux, 1895. "^ Die Acclimatisation der Europiier in den Tropen : Deutsche medicinische Wochen- Bchrift, 1898, Nos. 27 and 28. =* New York Medical Journal, March 18 and 25, 1899. Tni<: soLini'iiL's food; " nAT/oNS." C47 Hali.cd ]H'i)C, <:ii\\\U'(\ Ix'uiiK and pork, .and liurdia<;k- f)rovf'd U) ))('. a fon- tinuid ii-ritaril,, hy wliirJi ilic (loiiMcs w Tollowino; tivMo slunvs tlic monn nutrient of)mpositiV)n of i]w. four dietaries, and udniits of ready coMi[)ari.son of one witii another : Dietary. No. I. No. 11. No. III. No. IV. Average (iiijuitit.y, 52.9 .32.9 52.6 64.6 50.7 I'atH, 53.55 114.44 63.80 10.11 67.97 Carliohy- d rates, gruiuii. 630.39 666.94 617.24 69S.82 575.85 Protein, graiim. 123.19 106.69 106.88 104.26 109.76 Nitro(?ftn, graiuH. 18.78 16.92 16.95 10.71 17.34 Fuel value, [caloriefl. 3,677 3,825 3,063 2,947 3,.375 Total carbon, 350 grams; nitrogen to carbon, 1 : 20. The so-called "Filipino Ration" is as follows :^ Filipino Ration. Component articles and quantities. Substitutive articles and quantities. 12 ounces . 8 ounces . .32 ounce . 20 ounces . 8 ounces . 1 ounce . . 2 ounces . .08 gill . . .fi4 ounce . .02 ounce . ("Bacon 8 ounces. 8 ounces. Beef, fresh Flour 1 Fish, canned L Fish, fresh Hard bread 12 ounces. 12 ounces. 8 ounces. Baking powder, when in field and ovens are not Rice Potatoes Coftce, roasted and ground Onions 8 ounces. Salt Pepper, black Posts and Camps. Posts are permanent camps or those of position, and camps, in the usual sense, are temporary or incidental. At posts, the troops are housed in barracks, while at temporary camps they occupy tent* and ! It will be noticed that the first and sixth columns do not add up acconiing to (he totals expressed. The latter, however, being used in the table below, are retained unchanged. * General Ordei"s No. 47, War Depai-tment, Washington, April 3, 1908. 650 MILITARY HYGIENE. huts. The same sanitary considerations apply equally well to both, but choice of location of temporary camps in time of war is determined commonly by immediate and strategical considerations. Both should be laid out in such a manner as to insure proper air supply, cleanliness, Fig. 103. K'-.''l A Officer! Bath cul Sink Tent*. I*' Qffietn KItdMi, Held mi Staff Hc^ora ■f Non-Com staff Band o and Drum CorpiTent*. })* Battalion Offteert Tents, €!• • • • « "f Company OfffoenTinta W Wf\W W"- 'H' tt W' '9 '9' '9' in ''S """» • • • • • • • • •. Company Tenia. TJ 1 < I I t I I I ' ' ' Company KJtoAens. Ji * *■ ♦ Cempnny Bath and Sink Tentt. • • • • * * • * eoala64 t«tt •! tooh SV Explanation. •^ BTumlnff Wat«r ^^M Cooorote Fonndfttlon. Plan of camp (reduced so that scale of 64 feet to the inch no longer applies). and general salubrity, and should be as compact as is consistent with the principles of hygiene, for a compact camp is more easily cared for and defended, while one unnecessarily extended involves increased labor, slower delivery of orders and supplies, and greater difficulties in sani- tary policing. With the tactical and strategical requirements and gen- eral plan, which is a matter of regulation, the hygienist has nothing to do, and his interest lies only in the distances between different bodies rOSTS AN/) ('AMPS. 051 of men, tho sizo of oornjKuiy Jirciis, (Ik; (tiihic; Hp.'K;^ pfT rnuii, flif proper locution of, sinks, l.'ili'iiics, and iiriiiiils, llic nicuHuniH aiJoptcd for hurlatx; (lrainaji;sal (»(" scwaj^c, p;arl>af^c and Htiiblc rrijmurf, the watcr- HUj)])iy, and oilier niaUcrs having a hearin/j; on tlie liealtli of tlie trof»pH. ']'li(! ^cnei-id plan of a canip is shown in I*'i^. lO.'i, taken from flit* Jidiintry J)i'ill IJe^ulalion, and amended in (lie maltcr of distaiiees and intervals hy Dr. I*. (-. Harris, IT. S. A.,' since no distances and inter- vals arc f!;iven in the rej^idation, lor they rniiHt vary acc/»rdin^ lo the nature of the ^roinid and the strene;th of tin; (^onunand. The plan i.s made "on a basis of .'> men to a coriniion tent or 10 to a eonieal wall tent; the maxinnuii allowance; of tentaf^e is G men to a common tent and 20 to a conical wall." Sites. — One of the most important matters connected with military hygiene is the selection of a proper site for cam|)s. Kverythinj^ hear- ing on the health of those who are to occuj)y the camj) should he con- sidered important, and every eifort should Ik; made; to insure, so far a.s it is possible, that there is no ])oint of least resistance in the barriers against disease. If an unhealthy site is chosen, no amount of care can ward olf, though it may check the extent of, evil conse(|uences. In active wai'fare, choice of sites is not always a wide one, and convenience and necessity play a greater part than sanitary consideration. A\'hen practicable, they should be placed on high, well-drained ground Proximity to water is always necessary, and this may involve ex- posure to malarial infection ; but, other things being equal, the driest site should be selected. Where the choice is restricted, advantage should be taken, in cold weather, of any available protection from winds, and, in hot climates, from the burning sun. The general slope of the ground should be considered, so that surface drainage may be best provided for. The soil should be dry and porous ; clay and other soils of low permeability to air and moisture, but with high retentive power for the latter, should, if possible, be avoided. If the ground-water level is high, it should be lowered by tile draining or ditching, in case the camp is to be one of permanence. A clay soil or a soil underlaid at a short dis- tance by a clay soil is regarded commonly as the worst possible site for a camp, since it is retentive of water and is cold, and causes the atmos- phere immediately above to be damp. Old river bottoms, deep allu- vium, and marshy ground should be avoided. Grass land may com- monly be accepted as good camping ground, but ground covered with rank vegetation, as in the tropics, is not acceptable, because such is generally rich in decaying organic matter, and the presence of rank vegetation is in itself evidence either of a very humid atmosphere or of an undesirable degree of soil moisture. Lauds subject to periodical flooding, especially by salt water, should be avoided as unhealthy. Above all, it should be a rule to avoid old camp grounds, for these usually are left in a filthy condition by the previous occupants, and the soil is always contaminated extensively and, perhaps, infected. If an * Camps of Instruction, Reprint, Buffalo, Dec. 14, 189S. 652 MILITARY HYGIENE. old camp site is particularly desirable on account of the accessibility of wood, water, and g;rass (the three essentials demanded by the line officer), a position to windward and as near as is consistent with hy- gienic considerations may be selected. Dryness of the site and vicinity is of prime importance in its bear- ing on the health of troops, but too great dryness with much dust is hurtful to the eyes. A position on the side of a hill is warmer than one at the top and drier than one at the bottom, and is favorably situ- ated as regards that most essential provision in camp sanitation, drainage. Barracks. — Barracks are permanent structures for the lodgment of soldiers, and are built commonly of one or two stories, but not more. Each building of a group should be completely independent of the others and placed with reference to prevailing winds and exposure to the sun. It is essential that the site be dry ; the foundation walls solidly laid ; the walls, of whatever material constructed, dry and pro- tected against capillary moisture ; the floors, of hard wood, tightly laid ; and the ventilation efficient. Barrack rooms, which are the soldiers' living rooms as well as sleeping quarters, are generally made long and narrow, and each occupant has floor space and air space according to the regulations obtaining in the country which he serves. In this country, 600 cubic feet of air space per man are reckoned adequate, and this, in a room 12 feet from floor to ceiling, gives a floor space of 50 square feet. Cavalry and artillerymen are given somewhat more, on accoimt of the odors which cling to them from contact with horses. A less amount is allowed when troops are quartered in ordinary dwell- ings. At Southern posts, 800 cubic feet of air space and 70 square feet of floor space are allowed. In England, the allowances are the same as with us for infantrymen in the North ; in India, they are from 1500 cubic feet and 75 square feet to double those limits. In France, the cubic space allowed is 420 cubic feet for infantry and 500 for cavalry. In Germany, it is 500 cubic feet. The wash-rooms, urinals, and latrines should be placed with due regard to convenience and to general hygienic considerations. Ventilation should be planned with a view to the greatest possible reduction of the natural impurities due to occupancy, but with the pres- ent cubic space allowance, whatever the system employed, ideal results cannot be attained. Barrack life is necessarily one of overcrowding, but the conditions which now obtain are far superior to those which formerly prevailed. Tlie evils of overcrowding of soldiers were first brought to light by an investigation of the health of British soldiers in 1858. It was shown that, whereas the mortality rate of the popu- lation of England and Wales of the same age as the army was 9.2 for town and country and 7.7 for country alone, and 12.4 for the most unhealthy town (Manchester), that of the different arms of the service ranged from 11 for the household cavalry to 20.4 for the footguards. According to age periods, the mortality was distributed as follows : POSTS AND CAMI'S. fi-O.'J A >m , iir f nviliariH HA I iSi)l(|i('rn I/O . or , ..A f ( Iivili;iiiH '.i.'J, * I SoIiIhth ]H..i A .,,1 , .,r ( (Iivili:inH 10.2 " I SoldiciH IH.'l 1 .,r , iu I ( 'ivilillllH II.fi A^liH •'■' lo '10. ^ i. I I- II. •> Since tli(! soldiers wv.vv. picked men, all iipplicanls vvltli any evidence of weakness or tendency to diswise bein^ nijeetcd, tlie>i(! datn indicated a serions (condition of alVairs. CoinpMiison was made witli tlic rates obtainiiiji; amoiio; ili(« cImss (»!" ao;ri(Mllnial lahorer.-^, tlicir work, lik(! tliat of the soldiers, bein^ mainly <>iil <>( door.-^. It wonld be expect<;.'j tent be out out for a Hi)a(!(! 2 U'cX wide; on cadi Hide of tin; rid^*; an<] running; i\\v, c^iitin; Icii^tli of the ton!, cxrcpl 1 fool, front and rfjir, the (!aiiviis thus reinovf^l heiii/^ I'cplaecd hy heavy ro|K! netting' with a 2-inch mesh. Jn order heller- to reflect llie heiit niys, the fly slionld be made of white canvas, Ihe (enl ilself beinjf of d;nl< (janvaK, with a view to snlxhiiti^ the li^ht in lh(! inlerictr. An experinientid tent, mad(! nnd<\r orders of the Snr^eon-(jcneral, was j)il(h<(| within a few feet of a regrces coolei- than i\\v. rcgnlnr hospital tent, ('onipared with the conical wall tent, the tcmperatnre ranged 0.5 to ]8.5 degrees lower in the improved tent, which dilference " means in the tropi(;s all the difference between comfort and distress for the well and snch relief from great and depressing heat as wonld do miuih to bring abont recov- ery in the si(;k." The exjx'riniental tent demonstrates that no tent should be issued for use in the tropics without the protection afforded by a fly. The U. kS. A. Board of Equipment promptly adopted the imjirovcd hosjiital tent. Dr. Myles Standish, M. V. M./ first called attention to the intense white glare to which the occupant of the hospital tent is subjected from the covering above his head, and which must be a source of actual injury to eyes already in a pathological condition. Rea.soning from general laws, he recommends a jxile blue or an olive green as the safest color. In India, the British use a tent with a double fly, having an air space of 2373 cubic feet and accommodating 16 healthy or 8 sick men, which gives a far greater allowance of space than in the service else- where. For field service, tents of 686 cubic feet capacity, accommo- dating 16 British or 20 native soldiers, and smaller ones of 392 cubic feet capacity, accommodating 8 British or 10 native soldiers, are in use. Tents are arranged best in short single lines, the individual tents being distant from each other at least once and a half the tent's diam- eter ; the intervals are not fixed by regulation. If possible, the tent should face the east, so that when the day is advanced, the southern wall may be lifted so as to admit the sun's rays to the whole of the interior. Each tent should be ditched as soon as it is placed in position. The tent ditch should be 6 inches wide and 4 deep, and should con- nect with the company ditches, and these in turn with each other, forming a complete system of surface drainage. All surface drainage from higher ground should be prevented by being intercepted and turned aside. The floor of the tent should never be lowered by excavating, for 1 Color the Canvas of Hospital Tents. Reprint, Transactions of the Association of Military Surgeons of the United States, 1896, 656 MILITARY HYGIENE. nieu sboiild sleep above the level of the ground, and never below it. If the soil is not quite clean and lirni, it should be dug out to the depth of about a foot and replaced bv clean gravel or sand, if such is obtainable, and then covered with boards. Elevated platforms are eminently desirable, and tents not so provided should be moved eveiy week to the open spaces between, so that the sun may exert its purify- ing influence and, together with fresh air, may put the vacated sites again in a condition for occupancy. The floors of the tents should, when possible, be covered with loose boards, if these are obtainable ; and occasionally the surface of the soil should be scrajied and replaced with clean gravel or sand. In malarial and yellow fever districts, nettings to exclude mosquitoes, especially at night, and individual netting on light frame-work for the protection of the head, the other parts of the body being protected by clothing, will be found to have great influence in checking infection. Huts. — During cold "weather, wooden huts are much better adapted for occupation than tents, and have come into extensive use in the German, French, and English armies, both in war and in time of peace. The use of log cabins is advocated by Colonel Charles Smart, M.D., U. S. A., to house 4 men apiece. The inside dimensions given are 13 X 7 feet; walls, 6 feet; ridge, 10 feet from the floor; the door to open in the middle of one side ; the chimney opposite the door out- side the wall ; the roof consists of canvas 14X12 feet, with a larger fly. This is regarded as the best size and allowance, but the present tactics require squads of 8, for whom, according to Woi)dhull, " there should be two huts 8X11 feet end to end, 6 feet apart, with one con- tinuous roof and door in the adjacent ends, but not midway. The chimney should be in the middle of one long end. Two platforms each 6J X 4| feet, one lengthwise and one across the end, would ac- commodate 2 men, sleeping with their heads adjacent. The covered porch between the huts would be 6 X 9 feet in the clear, the sleeping platform be open beneath, and under no pretence should two-storied Ininks be allowed." On damp sites, the walls should be raised a foot from the surface ; but on dry soil, they may be built directly on the ground level, the soil well pounded down, covered with sand and gravel, and concreted. The floor of the huts raised from the ground is made best of split or dressed logs. The canvas roof and fly are attached in such a way that they may readily be removed when it is desired to admit the sun to the interior. Portable huts may be furnished, having frames of wood or iron. The German huts are made with wooden or iron frames covered Avith felt and lined with canvas. They are easily ventilated and Avarmed. The French huts are made circular in shape ; the walls are of boards wdth glass wdndows. They are easily ventilated and heated. The huts should be at least 10 feet apart at the ends, and the interspaces should be carefully protected from pollution. Water Supply. — It goes without saying, that one of the first consid- erations in the establishment of a permanent camp is an adequate sup- J'OSTS AND CAMI'S. fio? ply of |)otji])l(! wntcr, wliir.li Hiibjcci is prcsr-nlrd clscvvlK'n'. It, Ik ciiih- toinnry to iillow ;ii IcmsI, U ^.'iIIoms per <:;i|»it;i per dictii f'oi- all piirpoHOH, and iiH intKili more uh is j)riic-lic!il)l('. Watciw^loscfs and li.itliH r(;(jiiin', iiiiturully, u V(!ry ^(^ncroiis allowaiK^c. Ilospifals i((|iiirc tmifli nion; per capita tluin barnicks. I'oi- hoi-st's^ (Voin U to 10 ji^idlons j)fr diartment says on this point : " Sulphate of iron and other cheap antiseptics and deodorants may be used when necessary. But the necessity for their use is a reproach upon the sanitary police of a post, and should only be required under exceptional circumstances, The alvine discharges of healthy persons do not require disinfection, and when properly disposed of, do not require treatment with any chemical agent whatever. If water-closets or earth-closets are offen- sive, this is due to faulty construction, to insufficient supply of water or dry earth, or to neglect of ordinary cleanliness. The attempt to remedy such defects by the systematic use of antiseptics is expensive 42 658 MILITARY HYGIENE. and iinsatisfiictorv in its results. The same is true of foul drains, bad smelling urinals, accumulations of garbage, etc. The proper remedy for such conditions is cleanliness and strict sanitary police." AVhen there is reason to believe that infectious diseases are present in camps, the latrines and cesspools should be disinfected with milk of lime to the extent of one-twentieth of their contents, to which should be added every day an amount equal to at least a tenth of the daily addition of excrement. Hospital sewage is dangerous enough to warrant treatment on the spot with disinfectants. In the absence of a regular system of sewerage, Sternberg recom- mended cylindrical galvanized iron vessels 18 inches in depth and diameter, with a trough around the upper end 3 inches deep, filled with disinfectant. Into this, the cover fits, and thus serves as a valve and prevents the escape of foul odors and the entrance of flies. A second cover with a hole serves as a seat. The receptacle is to be partly filled with carbolic solution or the contents are to be treated with caustic lime, or ashes, or dry earth. These vessels should be removed at regular times, and clean ones should be substituted while they are removed, emptied, and cleaned. Sinks and Latrines. — A sink, in military parlance, is a cesspool or pri\y vault in a temporary camp ; usually, a trench from twelve to fifteen feet in length, about two feet in width and eight in depth, with the earth, which has been thrown up, piled along one side. The requi- site number should be dug before a camp is occupied or as quickly thereafter as possible. They should be placed to leeward, or in such position that the prevailing winds shall not convey the odor therefrom over the company areas, and they should never be placed near existing wells. They should not be placed any farther away from the men's quarters than is absolutely necessary. For convenience of use, a strong pole is laid horizontally on upright forks at the proper height and on the side opposite the excavated earth. The latter, kept as dry as possible, is thrown back each day over the deposited excreta, often with caustic lime, chlorinated lime, or ashes. Behring ' recommends, in case of necessity, from 5 to '7.5 liters of milk of lime for each 250 men ; Pfuhl ^ advises 400 cc. per man. The addition of chlorinated lime possesses a double advantage, since it not only acts as a disinfectant, but also serves to drive way flies, which otherwise collect and may become active agents in the spread of infec- tious disease. Small sinks for each company are regarded as much better on several accounts than one or more large ones for each regiment. They afford greater privacy when enclosed with brushwood, and are generally better looked after, since the responsibility for their care is more definitely fixed. When filled to within two feet of the surface, the remaining earth should be thrown in and rounded over, the site marked, and, at the same time, new trenches prepared. On breaking camp, all sinks, however little used, should be filled up and marked. X Zeitschrift fur Hygiene, IX., p. 395, ' Ibid., IV., p. 97. POSTS' AM) CAM/'S. 659 Wh(!ii (li(! |)f(il);il)l(' s(;iy ih \n l»c more lli.in of a [(;\v duyh' durution, the li()ri/(»nl;il |)<»l(:s uvc (•orimioiily r(|»l:H'(Ml l»v hox H(;alH, <>\)t:t] at tho hiU'.k. Ill wiiilcr, IIk; Irciiclics sIkhiM he ((Hiiplch-ly coycrcA by box H(!ii.t>t wil.li cdvcrs ; liiii^iiij^ oC lln' to|) oi- i-f;ii' >)(lc will !)<• iii;ceHHary for tlio |)r()|K!r throw iiifj:; in of" (lie cxt^avMlcd cMilii. TIh! vv<»I(I /(ilriiw is coiiiMioiily UHcd as syiioiiyiiioiis with Mink. It \h properly dcliiicd a.s " ji |)rivy or watcr-cloHct, ('spcfinlly in froiifrh form accommodating several at. th(! same tiiiK;."* A further deseriplion of a, lafcrino is clsevvliore ^iven (sec; paf^e 301). L;il lines are more eom- nionly installed in barracks or permanent camps. 'I hey n-«jnire fre- quent (lushing', if comiected with a system of" sewerage, and fn-qiient emptyinj*; and cleansiiiLT, il" iidt so connected. TIk; seats and floors should be kej)t thoroughly clean by periodical washing; twice daily Ih strongly recommended. TIrinals ajiart from sinks and latrines arc installed in both perma- nent and temj)orary camps, and in both it is essential that they be of easy access, and their use compelled on account of the nuisance arising from indiscriminate voiding of urine on the ground and of the possi- bility of the dissemination of typhoid fever by the urine; of ambula- tory cases of that disease and of convalescents therefrom. In inclement weather and at night, all parts of a camp, and especially the company areas, are liable to urinary contamination, which should be prevented as far as possible by stringent rules and constant vigilance. Inspections. — Under the Army Regulations, an amuial inspection of the buildings at every post is made by the commanding oftieer and quartermaster on the first day of March, and immediately afterward a report is submitted giving a description and showing the condition and capacity of each building, and the character and extent of any additions, alterations, and re})airs. Sanitary inspections are more fre- quent and more searching in character. The surgeon is required to ex- amine, at least once a month, and to note, in the medical history of the post, the sanitary condition of all public buildings, the drainage, sew- erage, amount and quality of water supply, clothing and the habits of the men, and character and cooking of the food, and immediately after such examination to report thereon in writing to the commanding officer, with such recommendations as he may deem projier. Su[)er- ficial inspection is not enough, for everything may look clean exter- nally and yet the general condition may be bad. The condition of the air is of much more importance during the sleeping hours than during the day ; therefore, ventilatiou should be investigated at night. AValls and floors should be ciirefully examined, especially if they are made of porous material. Walls found to be contaminated with organic filth should be scraped and then thoroughly whitewashed. The floors, whether of barracks, tents, or huts, should be scrupulously clean and dry ; the bedding should be free from damj>- ness ; the spare clothing and the men them^relves and their clothing in use should be clean. The site and inunediate surroundings of every 1 Standard Pictionarv. 660 MILITARY HYGIENE- permanent or temporary structure should be examined with particular reference to the drainage and general condition of the soil. Sanitary Police. — Exceedingly strict sanitary policing is necessary to keep a camp in a healthy condition. The responsibility for condition rests ^vith the commanding officer, but is shared in by the company officers, who must look after their quarters and men. Under the title of " officer of the day," company commanders serve in turn, each for a day, in charge of general sanitation, and each is responsible to his com- manding officer for the order and cleanliness of the camp on the day of his service. It has been demonstrated repeatedly that untrained or incx])erienced soldiers cannot be depended upon for thorough cleaning or keeping things clean, for they do not know how to take care of themselves, because at home they are looked after by others ; and unless sanitary police be very strict, a clean and everyway good natural site may quickly be contaminated and made unhealthy. Until discipline is well established, the enforcement of proper sanitary regulations is extremely difficult, for while they may be most carefully formulated, the neces- sary orders are difficult of enforcement. Even with the utmost care and vigilance, contamination of the site is only a question of time, but the more efficient the system, the longer is that time deferred. A camp in which no attention is paid to cleanliness of the company streets and to habits of personal clea»'iliness is sure to be an unhealthy one, and men who will permit such conditions to obtain are commonly bad soldiers in every sense of the word, with no esprit de corps, slovenly in all their habits, conspicuously attentive to sick call, and with no respect for themselves or their superiors. In such a camp, the development of epidemics of infectious diseases, particularly typhoid fever, is only a question of time, since it needs only the introduction of the specific germ and favorable opportunities for its dissemination. Since this disease is endemic in all parts of the country, it is not strange that among large numbers of men brought in from diffisrent quarters there should be one or more carriers of the infection. In any camp of whatever degree of efficiency in sanitar}^' police, unless such cases are recognized at once and their excreta com- pletely disinfected or otherwise disposed of, so that no danger shall be possible therefrom, the site is likely to become polluted and the bacilli to be distributed through the usual agencies. One of the first essentials of maintaining cleanliness in camp is good surface drainage. If the soil is damp, the site soon becomes an expanse of mud, owing to the constant impress of hundreds of feet. Mud assists in the conservation of refuse and filth which it envelops and masks, and hence arises the necessity for efficient and thorough ditching, and for filling up depressions likely to retain surface water. The usual pathways and sidewalks should be made as dry as possible by the appli- cation of gravel, and by such other methods as are applicable to each individual case. All refuse of whatsoever kind should be prevented from accumulating POSTS AND CAMf'S. 001 wltliin tlio liiKis; ovfTyiliiiip; slioiiM ]>(: proriijjily rfriiovod aiissil)l(', \>y hiiniinj^. Kifclicd icCiisc should f>c (l())0)-it< tlic well-known niiiiwoiiH mlor of swill, and tlins hcconK^ a nuisance, hiif if is an aflracfion for flif"<, wliifji, jjy tlieir invcsl iuation ofail sorts (»( lillli, Inclndinn- flic ficcal discharges in the Kinks, and tiicn of IIm' soldiers' Cood itotii in tin? kit^then and at iiichh, have arous forms of incinerators devised for the pur|)ose; Ijut on no account should it Ik; sprea|>iii('M, :\Y(' (;oiiiriiuiii(!iit<'(l hy I>r- (Jnciilciif. C" In plaiiiiiuf^ tiKiSc ciunps llic priiiiiiiy ohjccis wci'c In icinov tlif l> ilclMii- ji.s iiir an ])(),ssil)l(', IVoiii Ihc Inlriiics, \u |)r(»viiis, the food, its pre|)aration, (|iiality and method of serving, tlie latrines, urinals and sewers, and malving to the regimental (lommander a brief report of any unsanitary (conditions they may discover, this report to be forwarded the same day to the medical insjjeetor of the army at department headquarters. "One medical officer and one hosj)ital steward from each regiment will be recjuired to be present for duty with the regiment at all times of the day and night. "A daily siek call will be held, and slight eases of illness treated in quarters or in the regimental hosjiitalrs provided for that purpose, but all men who are likely to remain siek more than three days will be promptly sent to the General Hospital at the Presidio of San Fran- cisco. " If any case of infectious disease occurs, the fact ^vill l)e promjitly reported to the camp surgeon, who is authorized to make proper dispo- sition for its isolation and care. "An ambulance fully equipped with a team will be assigned to the camp by the commanding officer of the Presidio. This ambulance will report daily to the camp surgeon at sick call, remaining in the camp during the day, subject to his orders. Under no circumstances will this ambulance be used for any other ]nu'posc than the transportation of the sick, or medical supplies. The commanding oliicer of the Presidio wnll also cause another ambulance to be sent to the camp for service at night time. This ambulance mOI remain on duty from re- treat to reveille foj* uight emergency service. AVbeu the night ambu- lance reports for duty, the day ambulance will be relieved and returned to the post." " Company commanders will caution their mcu against exposure to the fogs and high winds that prevail here, especially in the early morning and evening, at which time overcoats avlII be worn. Riding on the ' dummy ' of the street cars, especially at night, is particularly hazardous to men recently returned from service in the tropics. GuaixJ duty and other military functions required at these hours will be held in overcoats, and at breakfast and supper the stoves in the dining-rooms will be providai with tires. The s;\le. by civilians, of food or di'iuk within the limits of the camp will be forbidden. " At retreat, urine tubs, two to each company, will be placed in each 664 MILITARY HYGIENE. company street, and men desiring to urinate at any time during the night will be required to use them. The tubs will be removed from the company street at reveille to a place convenient for tlie scavengers, who will remove, clean and place lime in them for use the next night. " The quartermaster's department will be required to provide an ample force of scavengers to clean the latrines and urinal troughs at least once daily, and to refill the troughs with milk of lime ; they will also remove all kitchen garbage, and either cremate it or dispose of it in such ]>lace as the quartermaster shall direct. Particular care will be enjoined on company cooks to keep grease traps clean, and to deposit all solid garbage in cans prepared for that purpose in time for its re- moval by the scavengers. " The quartermaster's department will furnish to each regiment an ample supply of necessary policing implements, to enable the men to thoroughly and effectively police the camp daily." These regulations, Dr. Greenleaf reports, were promptly carried out by officers and men, and, in spite of the fact that nearly every body of men brought some form of infectious disease, including typhoid fever, tropical dysentery, diphtheria, smallpox, measles, and mumps, not a single case of any infectious disease originated in the camps, all of the imported cases being promptly segregated from the command, all in- fected material disinfected or destroyed, and all men who had been exposed isolated and quarantined. In all these camps, the latrines and bath-houses were placed on the flanks and rear ; the kitchens and mess halls, in the central lines. In the rear of each mess hall, a zinc-lined wash trough, supplied with a dozen bib cocks, was placed to be used as a lavatory ; near the door of each kitchen was a grease trap connected with the sewer, and galva- nized cans for garbage and ashes were placed on the porch. Large caldrons for heating water for laundry and other purposes were set up in convenient places. Two galvanized wash-tubs were furnished to each company, and " night soil tubs were placed in every company street at ' tattoo ' for the use of the men during the night, a sentinel being posted in the street to see that the orders regarding their use were carried out." The construction of latrines and disposal of excreta were carried out according to the recommendations of a board of medical officers, consisting of Major Reed, U. S. A., and Majors Vaughan and Shakespeare, U. S. V., as follows : " A trough made of No. 22 galvanized iron, fourteen feet long, twenty-two inches wide at the top, parabolic in cross section, and with a maximum depth of eighteen inches, if set in a light wooden frame- work, which serves as a protective crate in transportation, gives sup- port to the ti^ough while in position, and serves for the attachment of a lid in two sections, furnished with seven seat holes. These holes are shaped so as to render soiling of the seat difficult, and a slanting board one foot wide, permanently fixed at a proper angle above the seat, pre- vents the men from getting up on it with their feet. When in position. 77//'; Df.'^h'Asns Of'' Tiff': s(>f,f>jRn. 666 one end of the troiifrh is nii.scrl four indnjH lii^li<;r ilian llu; otiicr. The troiifi;!! is plnccd in ,-in ordinary {'v;\\\u\ pr-ivv lion-c. Al tlic njtjKT (ind of ilu; iioufrli llicic is plar.cd a ^alviini/.id iron ^uttcrr of |)i(t|KT Ii((if;-Iit and inc^lination Icadinj^ inio llic tron;|li lo sfrvc as a urinal. '' TIk! rear- side (»(' llic ^iificr or tli;it attaclicd fo tlu- wall of tin- hnild- in^ is hif^her than llic (ronl, side, Id jircxcnl i-oilin^r ih,. jinildin^'-. 'I lie iron<.';li is prepared for llic rcccplion oC (!ic;il nmtlcr liy (illiii^ i( with water niilil a ccrlain level, indiealed liy a line on flic inside; of the trough, is reac,lie dry lime shonld also be placed in (he nrinal. The jinie in the trono'h is thoron()sing it to the flies and other insects. "Once a day the contents of these tronghs :ire pnmped out into an odorless excavator, carted away and jiroperly (lis))ose(l of The milk of lime destroys the typhoid bacillus, and the contents of the trough, if properly cared for, will be quite innocuous. Not only is the milk of lime and faical matter innocuous, but its value as a fertilizer is con- siderable." It may be stated, however, that these excellent results in sanitary police w^ere not brought about without outside assistance, for it was found advisable to employ a corps of civilian scavengers consisting of 2 overseers, 22 night scavengers, 54 day scavengers, and 17 teamsters, with 5 odorless excavating carts, 6 sanitary cars, and 12 dust carts. By means of this outside force, the camp was kept thoroughly clean, and the excreta were promptly removed and disposed of. The latrine troughs were emptied twice in twenty-four hours, and garbage and all manner of waste material were removed twice daily. The tent floors, kitchens, mess halls, and comj^any streets were swept daily by the soldiers themselves, and one man from each company did duty each day in the company latrine to keep it clean and stir the lime solutit)n frequently. During the past few years great im]irovements have been made in methods of disposing of garbage and human excrement tlu'ough the use of portable incinerators of different types, two of which have been tried out, with a large measure of success, by the United States War Department. The Diseases of the Soldier. While there are no diseases peculiar to the soldier, there are many to which the circumstances and conditions incident to camp life render him conspicuously susceptible. These are mainly of the preventable class, and may be largely checked by ]>roper regard to the principles of camp sanitation, by avoidance of polluted water, improper cooking, Q6Q MILITARY HYGIENE. overcrowding, and overwork, and, in some degree, by the incnlcation of the principles of moral living. It is difficult or imj)0ssible to determine how soldiers compare with civilians in the amount of sickness which they suffer, since we have no statistics of general morbidity, especially of corresponding age periods, of the civil population ; and even were such available, it would be necessary to bear in mind that the soldier is often on the sick list with ailments which, in civil life, wt)uld neither deter him from attending to his daily work nor cause him to go to the added expense of medical advice. The soldier has absolutely free medical attendance and care, and of this he freely avails himself, excepting, with many, in case of venereal troubles. Concerning the constitution of the medical corps, the hospital accom- modations, aild general administration, all of which are fixed by law and regulation, no descri]-)tion or discussion is necessary ; and a brief consideration of the prevalence and predisposing causes of the chief diseases of armies is all that lies within the scope of this work. It is a well-known fact that in both war and peace the greatest mor- tality among soldiers is from disease, and not from violence, the single exception which history records being afforded by the German army in the war of 1870 with France. In our war with Mexico, according to Woodhull, 935 of the regular force were killed or died of wounds, and 4714 died of disease in the field. .In the Civil War, 99,183 whites and 3417 negroes were killed or died of wounds, and 171,806 whites and 29,963 negroes died of disease. In our war with Spain and troubles in the Philippines, during the year from May 1, 1898, to April 30, 1899, according to the report of the Surgeon-General, 968 men were killed or died of wounds, injuries, and accidents, and 5438 died of disease. Typhoid fever was responsible for more than half the deaths from disease ; next in order came malaria, followed by pneu- monia, yellow fever, and smallpox. Tuberculosis. — In the large standing armies of the world, tubercu- losis has long played a leading part, due largely, as has been pointed out, to overcrowding and deficient ventilation, and to the enlistment of men in whom the disease is latent before entrance and developed by changes in habits of life, climate, etc. Yet, according to Colin,^ In- spector-General of Hygiene in the French Army, many persons with latent tuberculosis not only withstand the hardships of military service well, but even become stronger and generally healthier. According to a statement by Surgeon-General Schjerning at the Tuberculosis Con- gress in Berlin (1899), a decided decrease in tuberculosis has been observed in the German army, while in other armies an increase from year to year in loss of men from this cause may be looked for as a certainty, especially when large increases in enlistment necessitate the inclusion of many not fit for service. Colin's statistics of losses to the French array are corroborative of Schjerning's statement^ espe- cially those for the year 1895, when a large increase of the army, * Journal d'llygiene, March 1, 1900. TTiT': nis'i<:AS/':s' of 'rin<: sf)TJ)Ti-:n. (u;i noccHHitidinfT ;i rcdiKifion in ilic (|ii!ili(y (IciiiuiHlcd, wa.s fdllowi d li\' a nioi'c iiiiu'kcd iiicrcuHc in yearly Iohh. 'I'Ik; li^iiics follow : Year. IilH('lmi-K('H per 1000 Ii(!itMiH |j(!r 1000 uniiy Tot4il IrMN per IWIO armj iirtiiy HlniiiKlli. 'i.;5() HtriMiKtti. ilrciigth. 1888 1.18 6.48 1889 ■\.'M l.or, 6.99 IHDO 5.70 1.08 6.78 l,Si)l (i.IO 1. :',.'{ 7.4.'i ]S<)2 (•,j,r, 1. 01 7.59 18!).", (> '.')'.') 0.91 7.'J7 1 8!)1 ii'riry 1.01 7.50 1895 8.34 1.14 9.48 1896 7.34 0.94 8.'28 III \hc Knnlish scrNicc, plilliisis is the cliicC ciiiix' oC iiior(alit\' and invaliding, the annual lo.ss avera;ii't, over (inc li;il(" l<', <»!' sites near wliicli tlic coiiditionn are favorable to llic piiddlc-hrccdin!;- iiios«jiiilocs, (lie avoidance of nnncccs- surv ^oinji; about diiriiiL!,' tlie lioiii's when nioscjuitoes arc most active, prevention of access of iiios(|iiiloes lo tin; sicejjinj^ (juarters, ancl the sy.stcmiatic us(! ol" ))ro|)liyla(!(ic doses of •|iiiiiiiie morning and ni^lit. Whiskey is not lujcch'd as an adjiixaiit, ;iiid is more likely to be an injury liian an aid. Hot lea and eollce nre nioi'c hij/hly re- garded. Measles. — In all new levies of troops, measles is a seri(»ns imp<'di- ment to ciiieiency, for, once introduced, the disease s])reads rapidly througli the camp, es])eeially if the troops are hirgely from the c/)untiy, where they have esca])ed the diseases of childhood which ravage the population of cities and large towns. The importance of the disease appears, according to recent evidence, to be likely to be underrated by commanding olficers. Diarrhoeal Diseases in General. — Because of the lesser resistiince to specific infections, which appears to accompany even mild cf)nditions of diarrhwa, it is essential to take such measures and precautions as are ])ossible to prevent them. Among the prominent causes may be men- tioned the use of im]n-o])erly cooked, indigestible food, and chilling of the body, particularly at night while sleeping on the ground, even although separated from immediate contact therewith by rubber blan- kets. The prevention of the first cause needs hardly to be pointed out; for the prevention of the second, the habitual use of light flannel p-armcnts or abdominal bands is recommended. Sunstroke. — This consequence of extreme heat or over-cxertiou m high temperatures is very likely to be induced by imprudence in the matter of water supply, and by continuous work without periods for rest and recreation. According to Dr. Smart, U. S. A.,^ " If the allowance of water is scanty, it must, nevertheless, be used at regular intervals, but economically, lest it give out. There is manifestly less danger of a fulminant stroke with a stinted but steady supply than with full alloAvance for a given time followed by a period of enforced abstinence. On the other hand, if the supply is liberal, it may he in- dulged in freely and with advantage when the skin is acting well." He relates that, during a service of four years in the hot climate of Arizona, Avith commands of varying size, making long marches, often on scant allowance of water, he saw sunstroke on but one occasion, and in this instance, the rule to use the canteen in the early part of the march with caution, as if no more could be had until arrival in camp, 1 Philadelphia Medical Journal, January 19, 1901, p. 158. 670 MILITARY HYGIENE. was not followed. It was the rule, when a supply presented itself on the line of march, to use it freely, and then, on proceeding, to use the refilled canteens with the same caution as before. A canteen of tea, not necessarily strong, containing a little lemon juice, lime juice, or vinegar, is more desirable when obtainable than plain water. Venereal Diseases. — These are responsible for a very large amount of sickness in all armies, and their prevention has been the subject of much consideration by military authorities everywhei'e ; but the reme- dies against the prevailing high figures of morbidity, namely, scientific and practical control of prostitution, find ahvays and everywhere active ojjposition on the part of the public. (MIA l"IM<:il X. NAVAI. AND MARIN!-: IIVCIKNR TiiK ('(tndilioiis of lil'c at .sc^a in i-rhition lo liciiltli an; very difrcrcnt ill many rcspctits IVoni those \vlii<'li <»l)(ain asli(»r<'. Tin- K-Jifarin^ man, wIutc^ncm' lie g<»(' .'mSO mcii li:i\c ;i ciiiiiiikmi iiilcr'csl,, and ;iif ;il Iciiilcl lo l>y SGV(M1 ('(Mtks, (ilic of I he (irsi clilSH, I Wo oC tllC HOCOIld, ;iiis of the respiraiory organs (pail ietdarly tnherenlosis), rlienrna- tisni, diseases ol" the di vidcd, tlxy rriiiy he used in j)litc. \)v jipprovcd hy such olli(!(!r and lilted lo his Katislliction." VVlicn ai'tilicial heating is rwjuircd, use is made of"ht»jv<'s and nU^ixn heating'. ]ii Uu; lorwiaHtlc of Kuiling vcssoIh, Hmall s(|uar(! stovefl of cast iron wilh a ni(»\ahl(' cover an- cin|)loycd. 'V\n'y an; dirty, incori- veuicnt, and generally nnsatisliictory. GENERAL HYGIENE OF SHIPS. Of the very lirst ini|)orl;ince in IJie hygiene of ^liip- is {rciieral cleanliness of ship and pcisonncl. (Heanliness of the >lii|> retjuires constant watchfulness and nnieniillinjj^ iittention, ;iiid daily insj)eetion is necessary to insure that cleanliness is not wholly sujx-rlicial, since it often happens that, whereas tlu! decks and all visible portions are dean, parts which are out of si<^ht are not in a wholesome condition. Naval vessels of all countries are, as a class, much more carefully looked after in this respect than those of the merchant marine. In securino; cleanliness, it is a mistake to use wat(;r too frecjuently and in too great abundance, and great care should be taken that all sn|>er- fluous water is renioved as (juickly as possible from all parts below decks, since one of the cardinal directions is to keep dry, for damp ships are notoriously unhealthy. Tlie damjmess that condenses from the moist air u])on the surface of metal plates and overhead beams is a source of great annoyance from its constant dripping, and keej)s up a continual dampness. This can be remedied only by sheathing or coverings of non-conducting material, such as granulated cork or as- bestos fiber. The most difficult ]iarts to keep in even fairly sweet condition are the bilges, in which collects that most disagreeable and offensive liquid known as bifge-trafer, the internal drainage of the ship, much of which, in wooden ships, leaks from without inward, through the seams. The disgusting odor of bilge-water is due to the decomposition of the organic matters present, and to the reduction of sulphates of the salt water to sulphides. The bilges require periodical pumping, and are connected for this reason with pumps, known as bilge-pumps. The bilge-water removed is discharged into the sea, and after removal, the bilges are flushed ■with clean sea-water and again pumped out ; sometimes they are regularly deodorized and disinfected. Next in importance, on account of their commonly unwhole- some condition and the difficulty with Avhich they are made clean and kept so, are the peaks. In small vessels, the fore-peak very commonly causes fouling of the air of the crew's quarters in the fore- castle. From a hygienic standpoint, the stoke holds of steamers are of great importance, for here, in a very restricted space, exposed to excessive 680 NAVAL AND MARINE HYGIENE. heat from the furnaces, the stokers perform their exhausting office. The air of the stoke hohls is eonimonly not only excessively hot, but exceedingly foul, and these conditions can be abated only by proper ventilation, which may be secured either by means of mechanical appli- ances or windsails. Water-closets and latrines should be of as simple a type as possible and capable of effective flushing. The soil-pipes may dis- charge above or below the water line. Where closets mnst be located below the water line, s])ecial pum])ing arrangements are provided for their emptying and flushing. Their placing differs according to the size and character of the ships. Latrines for the crew are placed for- ward and completely disconnected from the forecastle. They are supplied at the rate of not less than three for every hundred men. Urinals are commonly a source of great nuisance, and hence require extra care. On passenger ships, three closets should be provided for every hun- dred persons carried, and they should be so located with reference to sleeping quarters that they may not give rise to nuisance. Whenever weather and other circumstances permit, all bedding should be thoroughly aired, each article being brought up from below and exposed separately, fastened to the rigging or upon the girt lines. Hammocks should be thoroughly cleaned and dried about once in every fortnight. Blankets should be washed with soap at least every six months; hammocks and all articles of bedding should be, when prac- ticable, exposed for part of each day to the direct action of the sunlight. For methods of disinfection and general cleansing, the reader is referred to the chapter on Quarantine. Personal cleanliness of the men is of even greater importance than cleanliness of their surroundings, and, indeed, the two go hand in hand, for men of cleanly habits will not permit their surroundings to be other- wise than wholesome, and those who are not naturally so inclined should be required to keep themselves clean. Each man should be allowed a sufficient supply of fresh water daily, and the necessary appliances for washing should be provided. In navies, the \yashing of the person is commonly made a part of the routine. Special provi- sion for the care of the person is required for those who have the dirt- iest work to perform, namely, the firemen and stokers, since their occupation precludes the use of much wearing apparel, and the air of the place where the work is laden with coal dust and so hot that their bodies are constantly bathed in perspiration. Short bath-tubs of gal- vanized iron, a sufficient number of wash-basins, and a reasonable allow- ance of water and soap, should be provided. Given the conveniences and encouragement to make use of them, the chances are that they will be appreciated and freely used. As in the case with soldiers, it is of very great importance that sailors should be kept busy and, at the same time, should have sufficient time for relaxation, which they should be encouraged to spend in such pur- suits as will conduce best to the promotion of cheerfulness and the pre- vention of ennui. nil A PTK/Il XT. 1^|{()I'I('AL lIVCIIvXK. THE SOLDIER AND THE CIVILIAN IN THE TROPICS. '^riMO Inllowiiiu; |);ii;'<'S, (Icnliiii:; with liy^ricnc in tlic trdjtif.-, Iiavo grcMlcr o'onci'iil ;i|>|)lic:il)ili(y lo the life nf i'i\ ili.iiis, who have ;i wide.' choice ill their mode of life and di.-t ril»iil ion of their time, hut the; Jiiaiii principles are c(]ually ap|)Iical)l(' to the life of the .\\\ (lie tropics; and Marjeod ^ (jilerH th(! same advi(',(! to niiyoiic whose lienil ;iiid l>Iood-veHHel8 an; not wliolly normal. It i.s also well to cIkio^c, if po,--il)le, the bcHt tim(! of year for land- ing. Tlier(! ar(;, it is true, only two sejisons in the tropieH, th(! :i\c\\ at all, i.s tal<(Mi nsnali}' in xci'v .small (|iianlilics, Asa rnlc, in hot rliinaU-H, it is not t('ne had or, at least, is didicnit to obtain. It speedily sours and beeornes unlit to drink. Condensed milk of irood quality is more to be de- pended upon. Vef^ctables slionld be thoroughly ettoked, or they will .seriously tax the digestive organs. Fruits shoidd be perfeetly ripe and sound; over-rij)eness is (juite as objee(ionabl(! as greenness. (Jver- indulgeuec^ in fruit, (!veu of the best quality, and especially in the sour fruits, is particularly to be avoided. Tea, coffee, and chocolate are advised in moderation. Lime juice with water or cold tea makes a most refreshing driidv. Tamarinds in water are also most grateful. If alcohol in any form is desired, the light wines diluted with ■water are recommended niore highly than beer. Spirits are generally con- demned, but there appears to be no valid reason why, when very largely diluted with water or soda water, they should exert a more pernicious intiueuce than wine only moderately extended. In any event, alcohol should be taken only with food. The Use of Alcohol in the Tropics. — Writers on tropical hygiene are almost unanimous in the opinion that, Avhatever may l)e said for and against the use of alcoholic drinks in other climates, their use in the tropics constitutes a distinct danger, and that much of disease commonly attributed to climate is due actually to alcohol. Especially is this true of the various renal and hepatic troubles. According to Treille,' the abuse of alcohol is the chief cause of the frequency of dis- eases of the liver, not alone among visiting Europeans, but among natives as Avell. Dr. Chr. Rasch,- speaking of the futility of talk about Euro]>eans getting accustomed to continued high temperature with liigh humidity, and describing the various steps in physical and meutal deterioration, to counteract which, one turns to alcohol and other stimulants, says that these, together with insomnia and enforced lack of exercise, bring about a general atonic condition, or, in other moixIs, a lowered physio- logical resistance to diseases in general. Dr. Breitenstern,^ who for ^ Principes d'Hygione coloniale. Paris, 1899. p. 272. * Allgemeine Zeitsehrift fiir Psvohiatrie, 1897, p. 7-15. •* Hygiene in deij Tropen, MiULTtiNSchrift fiir Gesnndheitspflege, 189S, 2^^os. 7 and 8. 686 , TROPICAL HYGIENE. twenty years serveil as an army surgeon in the Malay Archipelago, gives it as his o])inion, based on long observation, that total absti- nence from alcohol is far preferable to even the most moderate indul- gence. A writer in Manila has pointedly remarked couceruing the health of the American troops, "It is not so much the climate as the glass bottle Avhioh injures people out here/' which statement is corroborated by another who had seen actual service as a member of a company, many of whose members were total abstainers and the rest made up of moderate drinkers and those prone to excesses, the latter constitut- ing 20 to 25 per cent, of the whole. Of the latter class, only two returned home in approximately the same condition of health which they enjoyed at the time of enlistment. Of the moderate drinkers who coulined themselves to malt liquors, a large majority suffered more or less impairment of general health. But the total abstainers returned almost to a man in excellent health, having endured the same hardships of an active campaign. The same correspondent, speaking of the far greater harm induced by the stronger alcoholic drinks, relates that he had repeatedly seen American soldiers, after spending several hours under shelter, drinking round after round without perceptible harm, fall over with all the symptoms of sun- stroke as soon as they stepped into the glaring rays of the hot sun. On the other hand, in opposition to the general opinion adverse to even the moderate use of alcohol in the tropics. Dr. C. E. Woodruff,^ U. S. A., after a careful survey of the conditions obtaining in the Phil- ippines, declares that he would change the statement in the general order from headquarters of the army, July 2, 1898, "The history of other armies has demonstrated that in a hot climate abstinence from the use of intoxicating drink is essential to continued health and effi- ciency," to " Experience has demonstrated that in a hot climate the moderate use of intoxicating; drink is essential to continued health and efficiency." He asserts that the almost universal drinking must mean a natural defensive craving occasioned by the terrible nervous exhaus- tion, a true neurasthenia, due to long-continued exposure to great heat and atmospheric humidity, indicating that waste is greater than repair. He asserts that men who want no alcohol at home have this defen- sive craving for it in the Philippines, and cites Spanish authority that a daily ration of wane has been found necessary. Whiskey, when sufficiently diluted, is the equivalent of wine, and the Scotch variety is regarded by him as superior for the purpose to American, which soon occasions nausea. Beer, by reason of being conducive to colic, diarrhoea, headache, loss of appetite, and general distress, he regards as distinctly harmful. While advocating the moderate use of alcohol, he believes that the results of abuse are far more serious than at home. Concerning beer in the tropics, there is much divergence of opinion, some regarding it as a valuable safeguard against abuse of stronger ' Philadelphia Medical Journal, April 7, 1900, p. 768, 77//'; SOLDI Kit AND Till': < 'I VI LI AS IN Till-: Titni'ics. 'IH? alcolioIic.H, ()ili(!r,s a^nioiti^ with VVorKlrii(f (li:it, it is hiiniil'iil. It Ih Haid that the driiikln^ ofinucli hccr followed hy Inuivy Hlc('|»iii^^ |)rc(lisj»oHr!H to Hunntrokc: and licat a|)o|»l('xy. Clothing. — OiK! is advised to tal<r green material, and s|)e(^lacles with lne (•(ijored glasses. The head-covering shouhl he selected with (he douhle consideration of (^)mfort and protection for tlu! head and neck. The material of which it is made shouhl he chosen with regard to hieal climatic con- ditions. In a partictdarly (hy hot climate, ior instance, j)ith is the most suitahlo material, being lighter than cither cork or felt; but a hat made of this material is absolutely worthless in a wet climat<', since on being exposed to rain it absorbs water, becomes e.\eee(h"ngly h(javy therefrom, and is rechiced to a worthless, shapeless pulp. Hats should bo properly ventilated in the crown, and there should be a generou.s space for the free passage of air between the head-band and the inner side of the hat; that is to say, the head-band should be fastened to the crown of the hat at only a limited nmnber of points and with intervening small pieces of wood or other material, so that the band shall keep its proper shape. All head-covering of whatever form should alibrd pro[)cr protection for the sides of the head and the ears, as well as for the front and back. A pnggery affords additional pro- tection. The brim of the head-covering .should be lined with some material of a bluish or green color, as a relief to the eyes. The outside should be light in color. The head-band is made of leather, and is easily saturated with perspiration, and then hardens on drying; while it is yvQi, it is exceedingly uncomfortable. If covered with fine flannel, it will be found to be much more comfortable. Jackets and other outer garments should afford perfect freedom of action in both ridiug and walking. The Norfolk jacket is a favorite form, and may be made of duck, khaki, or similar niaterial. It is well to leave a few inches of the arm-scyes unstitched for the sake of ventilation. For shirts, a mixture of silk and wool, known as ka.shmir, is regarded as the best material, being very light in texture and j>er- fectly absorbent. Gauze undershirts with short sleeves, or with no sleeves at all, shoidd be worn beneath the .shirt. Elastic cotton and jean are the best materials, so far as comfort and durability are con- cerned, for drawers. If one is to do much ridiug, it is advised that as much care be ex- pended in the selection of a saddle as in selecting boots, since comfort in horseback riding in the tropics is very largely dependent upon the fit of the saddle. 688 TROPICAL HYGIENE. Care of the Person. — The irritating effect of hot winds, which fre- quently carry tine particles of sand and dust, and the iilare of the snu, Avhicli ettuduces to troubles with the eyes, should be guarded against. Not infrequently the ears, too, are affected injuriously by hot Avinds, but they are easily protected by external coverings or by cotton-wool plugs. The nose and lips are subject to cracking and uncomfortable dryness, which may be helped by cold cream or some similar a])])lica- tion. The nails should be kept closely pared, since they become bi'ittle and crack off. The skin, having a very important function to fulfil, should be kept thoroughly clean, if on no other account ; but bathing in too cold water or for too long a time should be avoided. Parasites abound in tro})ical climates, and should be looked for on the jjersou and removed with all care. Among these may be mentioned the chigoe, or jigger, an exceed- ingly troublesome small flea (^Sarcopsylla poietrans) which burrows beneath the skin, particularly of the feet, and beneath the nails. At first, it causes only itching, but if not then removed, sharp pain and inflammation ensue. A half teaspoouful of flowers of sulphur inside the shoe is said to be an efficient preventive. Another parasite of far greater im])ortance, especially to the troops in the Philippines, is that Avhicli occasions the dhobie itch, which can be avoided only by very great attention to personal cleanliness and frequent changing of under- clothes. It first attacks the perineum and axillae, and when the acute stage passes by and the inflammation somewhat subsides, the scales become rubbed off and reach the feet, where the trouble spreads rap- idly, causing intense itching with consequent scratching and the evil consequences thereof. Diarrhoea and constipation are alike to be avoided. The former should be checked at once, and should on no account be allowed to continue without treatment. It is easily brought on by imjiroper or ill-cooked foods, impure water, green and over-ripe fruit, sudden changes in the weather, and intemperance. Constipation should be avoided by the acquirement of a regular habit. Sometimes, a cup of tea or coffee on rising will act beneficially, and oatmeal and coarse bread, figs and prunes may be found to assist, but purgatives and enemata should be avoided, if possible to get along ^^dthout them. Tropical Diseases. — It is beyond the scope of this work to enter upon the field of tropical medicine, but it may be said, in general, that the diseases of hot climates are exceedingly varied. Some of them are peculiar to certain districts ; some are exaggerated forms of what we in the temperate zone regard as simple maladies. In general, it may be said that in the tropics one meets nearly all the diseases of the tem- perate zone plus a great variety of others, but some of our most com- mon diseases may be very rare in certain places. Thus, scarlet fever and diphtheria are rare in the tropics as a whole, tuberculosis is rare in parts of India and common and quickly fatal in other parts of the tropics. Pabies is more common in India than in England, and the victims are almost always Europeans. Eeprosy, beri-beri, and 77//'; ,s()ij)f/':n ani> Tifh' (HViuan /.v tiii-: thoi'ich. HMI) el(!|)li:inti;iHiM un; (U)iiiiii()ii -aiwdu^ IIk; ii;ili\cs, hut xcry nin- ainoii^ JOiir()|)(^juis. 'J'lir<)ii;:,li()iil, llic l-r()|)i('s, dyscnlcry kills iii:iiiy iddic |»c()|»jr; ;Miiiii;illy than cli()l(M';i, ;iii(l works jr|-c;ilcr liuvot; in armies lliaii flic coiit^rifiiii^ forocH. Typlioid i(!V(!r always apjicars sooner or later in camps of soldiers from temperate climates, aiirved to be tlu; most SMS(H'p(il)le. This disease and eliolera, ac<'ord- inj^ to Freeman, ranjly oeenr in India diirinj^ tlu- liotlcst mf)ntlis, when tlu! hurninc- rays of tlu; snn art as a ^ermi(;ide ; \)\\\ when tli(; niin.s conu! and swec;]) the accumulated surfaiu- dirt into the water courses, they (jui(!kly appear. For a most intcrestinf;; deserij)tion of the diseasc^s ol)serv'(!|>iy wen; the same lor all, and thai the onthnak was very limited in aks occur which are most diilicult or impossible U) trace to a water-borne cause, the water supply being in nuiny iust;ince.s above suspicion, and even of exceptional purity. During our war with Spain, investigation of tlie great prevalence of ty))hoid fever in the large (nimps in the South showed the abundant oj)])ortunity which exists for infection by flies, and demonstrated the necessity of thorough camp sanitation, and of excluding them from contact with both excreta and foods. Visiting the " sinks " at one time and the mess-tables at another, they have the widest opj>ortunity for spreading infection. The presence of plague bacilli in the intestines of flies lias been demonstrated repeatedly within recent years, first by Yersin in 1894, wlio, noting the large number of dead flies where the victims were being autopsied, crushed one fly and inoculated it into a guinea-pig, which died of the disease in forty-eight hours. Further investigiition showed the bacilli present in the intestines of the living fly, and led to the conclusion that they actually multiply therein. Nuttall ^ proved that flies may carry the disease, and that they themselves die of it. It is interesting to note that the statements of early writers to this eifect were, therefore, correct. Most of these were vague, and gave no intimation of how the contagion was carried ; but a Venetian, Mer- curialis, in 1577, wrote (De Pestilentia) that flies go to infected houses, alight upon the sick, and then convey the contagion to other houses and deposit it on bread and other foods. That flies may play a part in the s]>read of tuberculosis, too, seems probable, for the specific bacilli have repeatedly been found in virulent condition both in their intestines and in their excrements. Dr. Frederick T. Lord * came to the following conclusions : "1. Flies may ingest tubercular sputum and excrete tubercle bacilli, the virulence of which may last for at least fifteen days. 1 Berliner klinisclie Wochenschrift. 1892, p. 1213. ^ British IMedical Journal. Ansiust 10, 1895. 3 Centralblatt fiir Bakterioloa;ie, etc., XXII. (1897), Xo. 4, and XXIII. (1898), No. 15. ^ Boston Medical and Surgical Journal, Dec. 15, 1904. 694 THE RELATION OF INSECTS TO HUMAN DISEASES. " 2. The clanger of human infection from tubercalar fly-specks is by the ingestion of the specks on food. Spontaneous liberation of tubercle bacilli from fly-specks is unlikely. If mechanically disturbed, infec- tion of the surrounding air may occur. " As a corollary to these conclusions, it is suggested that — " 3. Tubercular material (sputum, pus from discharging sinuses, fecal matter from patients with intestinal tuberculosis, etc.) should be carefully protected from flies, lest they act as disseminators of the tubercle bacilli. " 4. During the fly season greater attention should be paid to the screening of rooms and hospital wards containing patients with tubercu- losis and laboratories where tubercular material is examined. " 5. As these precautions would not eliminate fly infection by patients at large, foodstuffs should be protected from flies which may already have ingested tubercular material." They are believed, also, to carry leprosy and various conjunctival diseases. According to Castellani and Chalmers ^ flies are capable of carrying the bacilli of dysentery and are, therefore, probably a prolific source of infection in tropical countries. The larvae of the common house-fly are sometimes found in the ali- mentary tract. Thus, Cohen ^ reports finding them in the dejections of a nursing infant, the ova having probably been deposited in its mouth ; and Bachmann ^ found them in the vomitus of a hard drinker, and later, after the administration of an infusion of pyrethrum, in large numbers in his fseces. Flies may also transport the eggs of Tcenia solium, Trichuris trichiura, Ascaris lumhricoides, and other parasites, and deposit them on foods. Other flies mentioned by Castellani and Chalmers are Stomoxys cal- citrans, the common stable fly found in houses, stables, and in the open near cattle. It bites all classes of mammals and is suspected of spread- ing trypanosomes, especially T. evansl. Glossina palpaUs (tse-tse-fly). The bite of this fly has long been known to be dangerous to animals, but Bruce first showed that it was responsible for the spread of Trypanosoma brucei and the cause of the disease nagana in horses. Furthermore, Bruce and Narbarro showed, in 1903, that Glossina p)alpalis is the means of transferring T. gamhi- ense, the cause of sleeping sickness. That T. gamhiense undergoes a cycle of development in Glossina palpalis has been shown through ex- periments recently by Kleine. FLEAS. In 1898, Siraonds^ advanced the idea that fleas from rats sick with plague might spread the disease to other rats, and even to man. He found the specific bacilli in such fleas, as did also Ogata.^ 1 Manual of Tropical Medicine, 1910, p. 992. 2 Deutsche medicinische Wochenschrift, March 24, 1898. ^ Ibid. * Annales de I'lnstitut Pasteur, XII., p. 625. ^ Centralblatt fiir Bakteriologie, etc., XXI., p. 769. liKDIiUaS. CDfj The rjiKistion wan iJioron^lily invcsli^Mtcd hy (lu; Iixliiui I'I.-i^ik; Coiriiriis.sioii in WH)^), and jiic riri(liii;^s (ifiliis ( 'orrwiiis.sioti :irc siuii/iiar- izcd by Jiliu; ' as Col lows : "That Ih'as (and Wiif^sj Uikcn (Vom pla^uc- sick ruts (iontain Jl. pcdlH, and tliat Honu! of tiicini n;rnain alivt; in the bodies of tho in.sil(>s of (leas vvlii(^li liavc previously fed on tli(; blood of animals Hullorinj^ vvil.li llic disease;; thai rat lleas bile man ; lliat nndc-r cxjtcri- montal conditions tin; infection i.s not traiisfcirrod from rat to rat in tlio absence of fleas," TIk; iKias most commonly res[)onsibl(! for this trans- fer are (JeratophylhM /(w-Mdua, the common rat flea of Knrojx! and the Unitcid States, and Lirniojtsy/fa c/icojh'x, tli(! eomnum rat fl llnixc in ;i tcnipcratnrc not too low for tliat of the tertian; and tlic lallcr will nol live at 05° F., which t<'(nperature is not too low lor llial of I lie (|nartan type. Malaria rarely o/-oc//.s/.v), U})on the surfitcc of which, clear spaces, ccntrovicrc.s, begin to apju-ar. Jn a short time, these become surrounded by minute spindle-shaped exjlls, fsporohlaMs, which divide into minute rods, sporozoitrfi, which soon fill the whole cyst, which bursts and liberates them through the outer wall into the abdominal cavity. They then rapidly jxnetrate the tissues to the salivary duct, and thence into the j)roboscis, from which they are di.s- charged with the salivary secretion into the blood of the next person bitten. From the time of entrance of the sexual forms into the mosquito to the completion of the ]irocess, about ten days elapse, and since the period of incubation in man is the same, it follows that, under favoring conditions of temperature (for in cool weather the process within the mosquito is slower), about twenty days must elapse between the appearance of a first case and that of another connected therewith. The inoculated sporozoites give rise to the successive asexual genera- tions above described. The tertian parasite invades the whole corpuscle; the quartan, nearly the whole ; the £estivo-autumnal, from a fifth to a fourth of its volume. The pigment granules in the tertian Ibrm are fine ; in the quartan, coarse ; in the wstivo-antumnal, very fine. Not alone man, bnt many of the lower animals, as cattle, sheep, monkeys, dogs, various species of birds, frogs, snakes, turtles, lizards, etc., are subject to malaria ; but the parasites are peculiar to each species, and are not transferable from one to another. Some yeare after Golgi and others of the Italian school had dif- ferentiated the several malarial parasites and traced their life cycle within the human subject, JSIanson, who had done much Avork in the investigation of mosquitoes as a causative agent of filariasis, announced, in 1894, his belief that malaria was caused by drinking water infected by mosquitoes or dust from the dried mud left on evaporation of the water in which they had bred. He believed that the female, ali-eady infested with the protozoon, laid her eggs and then died in the water, and was later devoured by the larvw. Bignami opposed this, and asserted that the infecticMi was conveyed directly by inoculation in the process of sucking blood. In 1895, Ross discovered the malarial crescents in the stomachs of 702 THE RELATION OF INSECTS TO HUMAN DISEASES. mosquitoes that had bitten a malarial subject, and followed them in their development into spheres and flagellated bodies, but was unable to find them in the body cavity or observe any metamorphosis there. For two years, Koss ^ endeavored to cultivate the parasite in mosquitoes, but without success, and he then ceased experimenting with the "brown and gray" species (Culex), and began anew with a few speci- mens of a larger kind having four black spots on the wings (^Anophelcny After these had fed on malarial blood, he observed, on examination of one of them, certain pigmented cells, "the pigment absolutely identiciil in appearance with the well-known characteristic pigment of the malarial parasite." In a second mosquito, killed a day later, the cells were observed to be larger. The supply of Anopheles having become ex- hausted, he worked with other kinds, but with no results ; but later ^ he announced that he had found the pigmented cells in a third " dapple- winged" mosquito fed on crescent-containing blood. In the mean- time, MacCallum, of Johns Hopkins,^ announced his discovery that with halteridum, a parasite of birds strictly analogous to the malarial parasite of man, the function of the flagellum is that of true sperma- tozoa. Ross then took up the study of bird parasites (Halteridium and Proteosoma), especially of the proteosoma of sparrows, larks, and crows, and was successful in growing the parasites in mosquitoes that had bitten sick sparrows, and in reproducing the disease in other bu-ds bitten by them. He observed the liberation of the sporozoites from the zygotes, their passage into the body cavity of the insects, and their presence in the salivary glands. His belief that Anopheles acts as a carrier of the malarial parasites was proved by Grassi, Bastianelli, and Bignami, who allowed different kinds of mosquitoes, including A. macu- lipennis, to bite persons afflicted with the sestivo-autumnal type of fever, and found only in the species mentioned the developmental changes described by him. Later, Bignami * reported that he, Grassi, and Bastianelli had cauglit a number of specimens of this mosquito in a malarious district twenty-two miles from Rome, and had re- leased them at the Santo Spirito Hospital in a room occupied for some years by a man who had been under constant observation and had had no kind of fever whatever. The experiment yielded positive re- sults, for the volunteer subject acquired the fever and yielded para- sites in his blood. The demonstration of the agency of these pests was thus complete, and the connection has been proved repeatedly on a much larger scale. Thus, Ross^ reports that of 21 persons in a camp near Calcutta, 17 who slept without the protection of mosquito- netting were seized with malaria, while the others who slept under nets escaped. Grassi's experience is equally convincing, although with- out a control. For eight consecutive days, accompanied by a family of seven, he left Rome each day at 5.30 in the afternoon and went to a 1 British Medical Journal, December 18, 1897, p. 1786. ^ Ibidem, February 26, 1898, p. 550. " Journal of Experimental Medicine, January 7, 1898. * BuUetino della E. Accad. Med. di Roma, XXV., 1898-1899. * British Medical Journal, July 22, 1899. MOSQUITOES. TO.'i cottajijo in a notoriously inaI:ir-ioiiH disfricl, hfiwc*'!! IJonif ;im<1 <^'ivil;i- vcccliiii, \vlicr<; (licy pjisscd tlic iii^lit.s in u (;ott;i;.n', flic \viii(ioWH ^^' which, ,sci'<:('iH'(l willi |)(!rroi;ilc(l y'ww,, WVWi \v\\ open all tin: time. Not OIK! of tli(! |>iii-ty was in the least an'rctcd. Tlic loii}i;Ar/r.s becfimini; inl'ecled. Koch and many others are .str()n(:;ly ol" the o|)inion that the ns(! of (juininc has had nif»rf; t^) do with the disappearance of malaria than anythinj^ else, but it is proiiablc tlmt there is some other as yet nm-ecooni/cd cause, and that all the influ- ences luentioucd have contributed in (lillcrent degrees. 'I'hat there is some such undiscovered local condition, nm-t be very evident when we consider the following' facts published by ( 'elli and CjIaspciHni :' Certain localities in Tuscany, which less than thirty years ajj^o were very mala- rious, are to-day, so iar as can be ascertained, in precisely the same geileral condition as obtained before malaria disajipeared tlierefnjm. The stagnant marsh-water swarms with Anopheles larvae, and the air above with myriads of the imagines. There is no lack of the malarial parasite for iniection of the mosquitoes, for the people go to other districts and retiu-n with malaria ; and yet, in spite of the presence of the essential factors for an extensive epidenn'c, no outbreak occurs. The children are robust and healthy, the adult population shows no effects of malaria, and many who have lived there all their lives have never had the slightest attack of the fever. This freedom is not due to acquired immunity, for the inhabitants take the disease when they go to malarious districts for work. The mosquitoes are not insusceptible to infection, for specimens captured there are readily infected by malarial blood in Rome. Quinine cannot be credited with being the cause of the exemption, for it is not used more extensively than elsewhere. In India, too, there are districts Avhich were formerly malarious, but are now com]iaratively healthy in spite of apparently unchanged conditions. But although Anopheles may exist where malaria is unknoMn, the converse is not true, for where malaria is, there, also, are mosquitoes. The assertion that in Java there are places where malaria abounds without mosquitoes, has been investigated by Koch, Avho found that mosquitoes were everywhere ]iresent where malaria prevailed. He found also a place in East Africa with all the conditions favorable to malaria excepting mosquitoes, but with no evidence of the disease. In many of the islands of Polynesia, where marshes are very extensive and all malarial conditions are present at their maximum, with the exception of mosquitoes, no malaria is known. It seems reasonable to assume that, given the necessary species of mosquitoes, the introduction of infected persons into a district would probably be followed by the appearance of other eases ; but there are, » Centralblatt fiir Bakteriologie, etc., Oct. 23, 1901, p. 523. 45 706 THE RELATION OF INSECTS TO HUMAN DISEASES. fortunately, a number of conditions which must be fulfiHotl in order to bring this about. First, the Anojjhch'i^ must be blood-drinkers ; sec- ond, they must bite the infected individuals ; third, they must then develop the pai-asite within themselves ; and, fourth, they must live to bite another person when the sporozoites are still present in the salivary duct. In addition, certain favoring conditions of temj^erature are required, both for the activity of the mosquito and for the development of the parasite. Should cold weather come on shortly after the malarial subject is bitten, no liarm might follow, for about ten days are required before the mos([uito becomes fully infective, and in a cold atmosphere she is sluggish and will not bite. Preventive Measures. — In order to prevent multiplication of Anoph- des, measures should be taken to diminish the number of breeding- places by drainage and other means, and the larv?e should be destroyed where it is not possible to accomplish removal of the water. The natural enemies of the larvae may be introduced at very slight expense and with a minimum of trouble. Among these, Howard mentions as most efficacious, sunfish, sticklebacks, and top-minnows. Where fish cannot be introduced, the application of the chea])est kerosene at regu- lar intervals will not only kill all larvse, but will prevent the impreg- nated female from laying her eggs. Kerosene spreads easily and does not evaporate too quickly, and a barrel will suffice for an area larger than two acres. A single application by means of mops or watering-pots — about an ounce to fifteen square feet, enough to give a very thin film — will remain for at least a week, and generally a fortnight ; and since a week must elapse for eggs to develop into pupae, a second appli- cation need not be made until about seventeen days have elapsed. The sick should be protected by mosquito-netting, and the same means should be employed to prevent access to the houses of the well, and for the protection of those who may be obliged to sleep in the open. Local applications to the skin (oil of pennyroyal, oil of eucalyptus, etc.) are not of much value. Fermi and Tonsini ^ have reported a noteworthy instance of diminu- tion in the amount of malaria after systematic destruction of the larvae of mosquitoes. The Island of Asinara, inhabited solely by convicts and their guards, has often been ravaged by malaria. The larvae of different species of mosquitoes were found in many wells and horse- ponds, and were treated with kerosene a number of times. Screens were placed in the windows and doors of the dormitories. The results were most satisfactory, only 9 cases of malaria occurring during the year, against 99 in the year preceding. If Anopheles gain access to houses, they may be destroyed by fumi- gation with sulphur dioxide, employing 1 pound of sulphur for each 1000 cubic feet of air space. For prophylaxis by means of quinine sulphate, the daily ingestion of 2.5 to 5 grains is advised. However efficacious this may be, it will have to be admitted that it is an expensive measure, for the mini- 1 Zeitschrift fiir Hygiene und Infectionskrankheiten, XXX., p. 534, MosQiJiroKS. 707 muni .S in l'liilad(l|)l)ia, and 77o;i in McmpliiH riS^f), '7.'}, '7.S, '70). liclAvccn I Mr, I jind I H,S;5, it cau-ed 2;{,;iP>« deaths at Kio dc Jancii-o, where, aeeordiiifr ti) (lonvea,^ previons t/» lH4f) it was unknown, heinn- introihieed in that year by the Jirazil from New Orleans and Havana, and by the Navarre from Bahia. From Rio it spread to all the towns in the bay. Between 1853 and HK)(), it ean.'^ed 35,952 deaths at Havana, where it had flonrislied eontinnou.'-lv for more than a eentury, and wliere, after a practical a])])lication rtf the knowledo;e concerning the method of its dissemination — the outcome of brilliant work on the part of Keed and his associates, of the United States Army — it was demonstrated that it could be completely eradicated, and that even thouo;h outbreaks shf)uld occur on shij)s arriving from in- fected jiorts, removal of the victims to the fever hos})itaI need give rise to no new cases. Inability to control the spread of the disease has hitherto been due to the fact that the manner of its dissemination was not known, and that all efforts to control it were exerted in tJie wrong directifm, in the belief, now shown to have been unfounded, that fomites, filth, and soil conditions were the distributing agencies. It was in 1848 that Dr. Josiab Nott, of Mobile, suggested that mosquitoes might be responsible for or connected Avith the spread of yellow fever, but the idea appears to have been received with indiffer- ence. In 1881, Dr. Finlay, of Havana, announced his theory- of mos- quito transference, and began his experiments, but it remained for Reed and his associates to demonstrate conclusively that mosquitoes are the principal, if not the sole, carriers of the exciting cause, and that fomites and filth have absolutely no influence whatever. The experiments proving both statements are exceedingly interest- ing. In October, 1900, Reed' reported positive results of exj^eri- ments conducted by himself and Drs. Carroll, Agramonte, and Lazear M'ith mosquitoes, Stcgomy'm. calopus, furnished by Dr. Finlav. Carrol) was bitten by one that had bitten four yellow fever patients, alternately severe and mild cases, respectively, twelve, six, four, and two days previously. Four days afterward he took to h."s bed, and on the fifth day his disease was diagnosed as yellow fever. Another subject was bitten by the same mosquito, and by three others that had previously bitten patients with the disease, and in seven days he also had the fever. Dr. Lazear was bitten without result by an infected mosquito 1 Medical Eeoord. October 26, IWl, p. 641. ■■^ Bulletin medical, Octoher 12, 1901, p. 861. ' Philadelphia Medical Journal, Octoher 27, 1900. 708 THE RELATION OF INSECTS TO HUMAN DISEASES. on August IGth, and bv anothei', an accidental stranger, on September 13th. In five days, he had a chill ; on the day following, the diagnosis of yellow fever was made, and in a week, the case terminated fatally. Between August 17th aud October 13th (fifty-seven days), these three were the only cases which occurred among 1400 non-immune Ameri- cans at Quemados. On November 20, 1900, an experiment station. Camp Lazear, was established at Columbia Barracks, Cuba, under tlie direction of Reed, who, with his former associates, continued the work with gratifying results. A very strict quarantine Mas established, and no non-immune was subjected to mosquito inoculation (with one exception) who had not passed the full period of incubation of yellow fever under close observation, nor was any non-immune who left the camp permitted to return under any circumstances. Twenty-one subjects presented themselves, mostly immigrant Spaniards seeking imnmnity, and the result in each case was positive. Experiments with fomites ^ were equally convincing in results. Three large boxes of sheets, pillow-slips, blankets, etc., contaminated with the discharges of yellow fever patients, many of them purposely soiled with black vomit, urine, and faces, were placed in a building of 2800 cubic feet capacity, tightly ceiled and battened, with small windows to prevent thorough circulation of air and wooden shutters to prevent the disinfectant action of sunlight. The windows were screened with wire gauze, and the entrance with a screen door. The articles were unpacked by Dr. Cooke and two privates, and they Avere shaken so that the specific agent might be disseminated throughout the room, if it were present. They were then used on the three beds ])ro- vided, and some were hung about the room and near the beds. For twenty consecutive nights, the three slept in the uninviting beds, and every morning they packed the filthy articles back into the boxes, and every evening unpacked and distributed tliem again. They passed their days in tents in quarantine. During their tour of service, other bedding, soiled with the bloody stools of a fatal case, was received in a most offensive stinking condition, and used with the rest. Then other non-immunes repeated the experiment for twenty-one nights, sleeping in the very garments which had be:'n used by patients. Then these subjects were followed l)y others, who, for fourteen nights out of twenty, slept with pillows covered with towels that had been thoroughly soiled with blood drawn from a case of well-marked yellow fever on the first day of the disease. The result of the exposure of these non- immunes in relays for nine weeks was wholly negative, for not one had the first symptom of yellow fever. Not so, however, in the case of a man who was exposed in a building of similar size, thoroughly ventilated, and containing only disinfected articles plus infected mos- quitoes. On December 15, 1900, 15 of the insects were set free, and he Avas soon bitten several times. Later, he was bitten again, and also on the following day. He contracted the disease ; but 2 men who ^ Kepoited in Medical Kecord, October 26, 1901, and in other American journals, M()H(/(!i'r<)i':s. 700 wlopt for ci^lilccii iiiL";!!!.^ in ;i li;il(' 'if l he i-ooni w liidi wa.s wirfMi''! IVoni the olJuii' . '111(1 (Voni llic rii()S(|iiil,oc.s hy iicltiiij/, had no ! lo lie deflniir'ly seliled that: it is not- Sanarelli's I',. U'lcroiilcH. The conchisions ari"i\-ed ;il 1)\- iw'ed, ^ ';nr()ll, ;ind .\i_M-atnonle, and re|)orLed to tlie A nieriean Medical Associal ion, are, in hricf, as foHous : '^rh(; interrn(>(liat(^ iiost is the Sl('(/()mi/i(t. ca.lo/»iis^ which is eajtahh; of transmit lino; Ihc disease alter an iiitci'va! of about twelve davs or h)n<:;ei" alter becomiiit;' eonfaminaled by biting a ]»erson ab'ea«lv sick. 'I'he disease can be caused by subetilaneous injection of blood from the o'cneral circulation during' the lirst or second day of si(;llaced about table legs to prevent inroads of red ants, horse-troughs, leaves of the Agave Americana, and generally in any collection of still water. The New Orleans IMosquito Commission' found the larvoe in 128 of 210 cisterns examined by them. According to this authority, the life cycle of Stegomyia is somewhat different from that of other genera, and these diiferences may necessitate more stringent measures than will suffice for the suppression of Culices and Anopheles, for the eggs hatch earlier (ten to twenty-four hours), and the larval (six and one-half to eight days) and pupal stages (two days) are much shorter, so that full development requires from two to four days less than for Cidex pungens, and two weeks less than for any species of Anopheles. According to Reed and Carroll, the eggs begin Fig. in. Fig. 112. Stegomyia fasciata. Male. (After Howard. Stegomyia fasciata. Female. (After Howard.) to hatch, as a rule, on the third day, and the process may last about a week ; the larval stage lasts seven or eight days and the pupal stage two days ; the shortest time for complete development observed by them was nine and one-half days. At an average temperature of 75° F. or higher, the species multiplies abundantly, but exposure to a lower temperature for even a short time daily causes much retardation, and eggs kept at 68° F. do not hatch. They found that newly hatched larvae kept at 68° F. develop slowly, and require twenty days to reach the pupal stage ; kept at 50° F., they fail to reach the pupal stage. Although low temperatures are destructive of the larvse, it is other- wise with the eggs, which Reed and Carroll found to be very resistant to the influence of dryness and cold. They observed that eggs which had been dried on filter-paper and kept ninety days hatched promptly ^ New Orleans Medical and Surgical Journal, January, 1902. M<)S(/iiiT()i<:s. 71 J on bciiifj^ j)I;u!('(l In walci'. hricd c^j^h, hr<>n/r|it. from Ilavnna to Wiifsliin^lon in l^'chniaiy, were easily liah-licd in iVIav, aixl f'nrnihlir;(l about ()() \)vv (Thl. of llic usual iiiinihcr' of larva; liat<'lu'- tr(»|)i(;:il (',(»iiMtri(!S, and in tliis (country as l;ir noitli a.-^ ( liarlc.slon, S. (,'. Jn many |»lac-(ss, a liall", and even niofc, (»!' the ]M»j)nlati(»n arc found fo bo infcstcid. Accord inl»s«'rvclasma. Flagellated forms were observed also in some cases when the blood had stood for some time. Further observation and study are obviously desirable and necessary. 1 Medical Record, February 8, 1902. CHAPTEK XIII. HYGIENE OF OCCUPATION. The influence of occupation on health and length of life has been the subject of much investigation since attention was first called to its importance by Professor Bernardino Kamazzini, of Padua, in 1700, but more particularly during the last half century. Although his work was translated anonymously into English as early as 1705, the subject appears to have been one that did not appeal with any special force to English social scientists and medical men, for the first English work of any importance was that by Mr. C. Turner Thackrah, a pnictitioner of Leeds, ou The Effects of the PrinGvpal Arbi, Trades and Professions, and of Civ'iG States and Habits of Living, on Health and Longevity, published in 1831. A French translation of the work of Ramazzini appeared in 1777, and formed the groundwork of P. Patissier's Traite des 3Ialad'ies des Artisans et de celles qui Resultent des Liverses Pro- fessions, d'apr^s Pamazzini, which was published at Paris in 1822. It was translated early also into German ; but the first work of any importance on the subject by a German writer was that of Halfort, Entstehung, Verlauf, und Behandlung der Krankheiten der Kunstler und Gewerbetreibenden, published at Berlin in 1845. Since the awakening of interest in the subject in England, France, Germany, and other European countries, and the United States, it has been extensively and minutely studied in all its aspects, and to-day its bibliogra]>hy includes thousands of titles, mostly, however, as would naturally be supposed, of monographs and memoranda pertaining to individual callings. From this vast amount of material from all sources, numerous tables have been constructed, showing, it is generally supposed, liow the various occupations stand relatively in the amount of influence which they exert on the longevity of those engaged in them. From these tables it appears, for example, that those who follow some particular calling are more prone to contract certain dis- eases than those engaged in another ; that in each hundred individuals of some one class, a greater number of deaths will occur in a year than in each hundred of another ; that the average age at death of those engaged in one employment is lower or higher than that of those in another, and so on. As in all findings based upon groups of units with, perha[)S, but one common bond, each unit being subject to a variety of outside influences, the conclusions drawn from this vast mass of material are influenced largely by fallacy, and include wheat and chaff, fact and fancy. In 716 IIYdlKNK OF OCaiirATION. 717 mnny cihcs, ^cihm'mI Hlnfcincrils iin; hnncd upon hii(;li ;i sli^lil, foiinda- tioii MM l(» iii(lii:i(c (hill, (iicir jiiitliorH an; po.s.scM.scd of tlial, dcj^rfc of p;(!iiiii,s wliicli lias hccn defined as tlic ability to ^reneralize Irotn a Hingl(! inslance. In many others, thon it, the length of time which one may serve before engaging in another, the peculiar conditions under which the calling is pursued, and the prob- able character of the influences which aifect the well-being of the in- dividual while he is not immediately engaged ; that is to say, his home surroundings, his personal habits, the nature of his relaxations, the quality of his food, and other factors. Tables based on foreign statis- tics should, furthermore, be not too freely accepted as applicable to home conditions, owing to differences in racial peculiarities and of conditions under which those engaged work and live, for one can hardly suppose that any one class works and lives under the same conditions in all countries. The conditions which govern the choice of an occupation are of very great importance. Many callings demand men of robust build and good health, and manifestly are unsuited to the weakling, who natu- rally is attracted to other occupations of a lighter character. On this score alone, statistics may be grossly fallacious. For example, in cer- tain tables it will be observed that the class designated as clerks have a low average age at death, and from this it may be inferred that the calling is one which is intrinsically incompatible with long life. But is it fraught with danger? Is it conducted under peculiar conditions which tend to bring its unfortunate followers to an early grave? Or is it not rather the fact that it is the refuge of a great number of those whose physical powers are such that they are unsuited to employments which call for greater robustness, and who, inevitably marked for an early death, regardless of their calling, reduce the average age at death of the entire class. On the other hand, certain occupations involving m^ch severe mus- cular effort appear to be conducive to long life, in spite of the condi- tions under which they are pursued. Here must be borne in mind that in these, the weaker individuals and those whose powers begin to fail are forced into other occupations, and that those who remain until the end show an average age at death which is eloquent of the benign influence of the calling. It is undoubtedly true that muscular efifbrt, carried to excess, will undermine the health ; but not forced beyond reasonable limits, and particularly if carried on under good hygienic surroundings, instead of being in itself prejudicial to health, is promotive of it. Those who are forced into lighter occupations may find the change advantageous ; or, on the other hand, entering upon them already broken in health, may help to reduce the average age at death of all those engaged therein. Another influence having a bearing on the choice of occupation is the high wage offered to attract workmen to trades which are properly IIYdlKNE OF OCrjdl'ATfON. 7 Hi conceded to Ix; dMii^crons lo li<;illli. Tlics*' mh' ii:i(iir;dly iiiirittractive to men of soniid body :iiif professors exceeds ')(). The manifest absurdity of attempting comparisons oi' the healthfidness of these two oc(;up;iti()ns is brouirht out still farther by reversing the case, and sup- posing the professors to die oif at 23 and the students at oO. Sinrje even advanced students in tlie professioiuil schools ])a-^s, as a rule, out of the student (;lass and into their chosen fields of usefulness long Itefore their thirtieth year, it cannot cause suqirise that those wdio die before their training is completed do uot show a high average age at death ; and, on the other hand, since men of learning are not ordinarily called ujion to assume the duties of professors until they have passed through the lower grades which lead to that rank, it is to be exjiected that their average age at death will be fairly high. To compare lieutenants and major-generals, shipping-clerks and retired merchants, apprentices and master carpenters, would be no more absurd. The average age at death of any one calling must be largely influenced l)y the relative number of individuals of the different age periods engaged therein, just as is the case with the population in general. Another fact that affects the age at which work is undertaken is a very low wage offered even in times of prosperity, so low as to be no inducement to heads of families, but sufficiently high to cause them to help out their financial condition by making use of their offspring. Before proceeding to a classification of occupations according to the circumstances which determine their healthfulness, it is desirable to consider the significance of the somewhat loosely applied term, occupa- tion diseases. Every form of occupation and every form of life of leisure has some attendant circumstances which may at some time, in one way or another, bring about a predisposition to some form of disease ; and to regard every disease of an artisan, tradesman, or pro- fessional man as attributable to his particular calling, is to fall into a common inexcusable error, for workers and drones have most diseases in common. It is beyond dispute that certain pathological conditions are caused and others promoted by certain occupations, and it is equally true that most diseases already acquired may be influenced for better or worse by one or another cjilling. 720 HYGIENE OF OCCUPATION. The true occupation disease is tliat which in all probabilit)'' would not have been acquired bad the individual not engaged in his par- ticular calling or some other in Avhich the conditions are essentially similar. As an instance, may be cited the lead jiaralysis of the house painter, potter, compositor, and file-cutter. Certain diseases of com- mon occurrence in tlve population at large are promoted by the condi- tions under which various callings are carried on, but these cannot properly be called occupation diseases, since the exciting cause is in no way a part of the business, and under better hygienic management, combined with more favorable outside influences, might be avoided. As a conspicuous instance of this class, may be cited the tuberculosis of dressmakers, cutlery grinders, and operatives in the cotton and flax industries, promoted by overcrowding and inhalation of dust while at work, and by all extraneous conditions tending to lower vitality. The plying of the needle is in itself in no way inimical to the in- tegrity of the lungs ; the grinding of the steel implement on the wheel and the running of the loom send forth none of the specific bacilli ; but the overcrowding in the one case, and the unavoidable inhalation of irritating dust in the others, bring about the conditions which ofier fertile soil to the germ of the disease. Certain conditions are influenced for better or worse by different occupations, as has been stated. Among these may be mentioned anaemia, which not uncommonly is classed among the diseases of occu- pation. Under the conditions of many indoor callings, this state is easily brought about, or, if already existing, increased ; but, on the other hand, under those of outdoor occupation, it is not likely to be induced, and, if already existing, may be made to disappear. Many occujwtions, for easily explainable reasons, draw their workers largely from that portion of the population which is, if not already diseased, predisposed by heredity, habit, and home surroundings to anaemia, tu- berculosis, and other disorders, the onset of which may be hastened or delayed, according to circumstances. In these, and in occupations in general, it is not an easy matter to determine correctly the amount of influence properly chargeable to the calling when disease appears, since the conditions under which a trade is carried on may be widely vari- able, and their influence for good or evil exceedingly complex. Among these conditions may be mentioned indoor confinement, nature of ma- terials, geographical location, and wages paid. Whether an occupation is carried on indoors or outdoors, is of much importance, for, other things being equal, outdoor employment is far more conducive to health than is confinement, even in well-venti- lated fiictories, in which, with the best of systems, the air cannot be maintained in the condition of purity which obtains outside. Even those callings which subject their followers to great vicissitudes of weather appear to be more conducive to robustness than those carried on indoors, particularly if tlie nature of the work is such as to call for freedom of movement and great bodily activity. The sailor, the letter-carrier, or the farm hand, for example, working in the open (![.A,SSlI<'l('y\'l'I(>N OF OCCIJI'ATIONS. 721 ;uf, in liciil ;iii arc |»ackcd into (piai'tcrs no larj^cr tliun absobitcly necessary for IIk; pcrCorinanfM; of their daily task, impossible of ])ro|)er ventilation witliont an exj)cn- sivc incclianical system, so great is the overcrowding, and, as i.s naturally to be supposed, overheated. Here, tlie unfortunatcH sjKjnd a fairly long day, leaving at night to go to homes |)erliap.s no less unsanitary. If not already so when they begin, they ix'come, aft<^r a time, anaiuiic, dyspeptic, and depressed, these conditions, as in many other callings, being promoted by lack of ex(u-cise, by ill-chosen and badly cooked food, and by absence of licahhful recreations. They become greatly susce])tiblc to cold, and hen(-e opposed to the admission of fresh air from without. Breathing cxcremental air l)y day and night, denying themselves proper food, their minds (lci)resscd, it is not to be wondered at that their condition invites disease, more particularly the one which stands forth conspicuously as a consequence of over- crowding; namely, ]iulmonary consumption. The onset is insidious. Beginning with a cold that resists being " thrown off," the cough be- comes chronic ; they continue to lose weight and strength, and the end can be foreseen. It is not to be understood that these callings are always or even usually associated with these conditions ; but when they are, the result is generally the same. 2. Occupations Involving Exposure to Irritating and Poisonous Gases and Fumes. This class includes a great variety of callings which may or may not be intrinsically dangerous, according t(i individual circumstances. In many cases, the danger may be much lessened by due regard to personal hygiene and by the use of respirators. These are simple pieces of apparatus designed to remove noxious matters from the air, on its way to the respiratory passages. It is the rule, however, that ^vorkmcn refuse to wear them after the first days, even though well aware of the possible consequences of laying them aside. One reason for this is that not one of the several forms invented can be worn with any degree of comfort. They demand faster respiration, soon get wet with expired moisture, and cause excessive perspirati<^n. Furthermore, they cannot be made to fit tightly, and so, even Avheu conscientiously w^orn, they only partially perform their office. The 724 HYGIENE OF OCCUPATION. mnjoritv of them are designed to filter out dust, but all are made on essentially the same prineiple, those intended for noxious fumes con- taining spongy or other absorbent material, wet witli agents which exert a neutralizing influence. One form consists of a muzzle of fine wire gauze, single or double, on a metallic frame. If made with a single layer, it is lined with cot- ton-Avool, .kept in place by a very loosely woven fabric stitched to the wire meshes ; if made double, the intervening space is occupied by a piece of thin flannel. Another form is made of woven or knitted stuff, instead of wire. This is said to be even hotter than the first mentioned, particularly in summer, and both are extremely uncomfortable. A third form, made of pieces of flat sponge large enough to cover the nose and mouth, interferes very much with free respiration. Another, consisting of a large bag of fine cambric, is said to be less objection- able, but is difficult to fasten tightly. Aside from the discomfort caused by respirators of whatever form, the operatives have another, a senseless, objection to their use, women complaining that they are made to " look ridiculous," and men being moved to discard them by the gibes of their more reckless fellows. {a) Irritating Gases and Fumes. — As examples of irritating gases or fumes, may be cited ammonia, chlorine, sulphur dioxide, hydro- chloric acid, and nitrous fumes. In small amounts, they cause, per- hajjs, no more disturbance than a slight tickling cough, but in large amounts, they bring about great discomfort and acute and chronic catarrhal conditions. Chlorine, which is used or given off very extensively in a number of industries, is unimportant when it is present in the air in very small traces ; but when in large amounts, it is said to cause minor catarrhal troubles and diminution or even loss of the sense of smell. It i^r said by Pettenkofer that from 1 to 5 parts of chlorine in 100,000 of air are sufficient to affect the lungs ; that 40 to 60 parts in 100,000 will pro- duce alarming symptoms ; and that more than 60 parts will cause death. It is given off in the processes of making and using bleaching powder, in the operation of glazing bricks, and in various other processes. Among the workmen who make use of bleaching powder, the occur- rence of bronchitis, asthma, and caries of the teeth, is noticeably frequent. Hydrochloric acid fumes are given off in various industries, and es- pecially from alkali works, the immediate neighborhood of which is likely to be barren of vegetation in consequence thereof. They are given off also in the process of galvanizing iron, the first part of the work consisting in "pickling" the iron in the acid to clean it and to prevent the presence of oxide on the surface when it is dipped into the molten zinc. These fumes act much less energetically on the respira- tory passages than chlorine. Pettenkofer states that as much as 1 part in 1,000 of air can be borne without difficulty by men who are accus- tomed to it, but that this amount cannot be exceeded. In the galvan- izing process, the workmen are exposed also to the dense fumes arising I'OISONOaS (I ASKS AND FUMhlS. 725 from tlui Kill iuninoiiiiKt wliirli is, IVoiri (iiiic lo litiic, lliivtwn ii|k»ii tlw HurfiKH! ()(" IIk! iiiollcii /inc. 'I'licsc urc more iii.'^ii|)|»iiil;il)|<- than llic a(!i(I Cnnics. Snl|)linf (lioxiflc is csoKcd in llic snicli inn of \;iiiriii- orcH, in pn-- |):u'in,tj;' Intps, in (lie niMiiiiliicI mi<' <>(' -iil|iliiiric ;i<'iil ;mmI oI' <»ri- niid nol iMri((|ii(iil ly in dcatli. I)catli hu\\u>{\i\m^ occnrs witliin a, (cvv lioin's ns(!(jii(^n(i(' of wliic.li IIk' |>r(i(ln<'t (•(int;iin(- globinuria. The symptoms snbsidcd in ;i lew days, leavin;.'- llic jcilicnts in a condition of aiiiumia and pronoinK-ed malnntrition. The vapors of" wooil ak',ohol have within reeent years attnicted eon- sich'rabh' nttention by renson of their disjistrons eneds npon vision. Since 1oisoiiiiij^ ariwH almost wlioUy in the W(»ik of decoration, the ])ovv(J(;r which i.s diiKt^(!l;il)l(^ "... " " iuiirniil "... " " riii.xcil "... " " iioii iliist V I i';i(lcs I'neumonla. 17.4 O.i) «.4 7.7 r,.o •I.e. I'hthlNlii. 28.0 2.').'2 20.8 22.fi II. I I>lgMtive dborden. 17.8 16.6 l.'i.7 20.2 10,2 16.0 Willi i'ct;;ir IIk' iiiniiciicc uC t lie (IIITcrcnl kinds of dust occw- jKitioiis, one iiiiisl not lose .sinlit of llic liict that <|ii;intity a.s well a.s ([uality sliould he considered, and that hieal eoiiditioiiH of ventilation luivc a, V(My decaded hearing. Ainoni>' th(^ <)c,('n|)ations in which nielalhc (hi.-t i.s ^iven off in not- able anionnts, that which stands foitii most con.sj)ic;nonsly a.s dan- gerous is stcel-o^rinding. In this work, the (hmgor varies invcr.sdy with the si/e of the object ground ; that is to .say, the smaller the object, the greater the danger. This is because largo objects can be ground in the wet way, but very small ones, as needles, must be ground dry and require constrained attitude and close inspection, and thus the grinder constantly inhales the very fine, sharp particles of steel that are thrown off in the process. These, by constant irritation of the mucous meml)ranes of tlie air-passages, prej)are them for the reception of the specific organisms of pneumonia and phthisis. At first, the cough is dry, but in a short time is accompanied by expectora- tion. Among those individuals who have followed the work for a year or longer under the usual conditions, a sound man is rare. Their average age ;it death is stated variously between twenty-five and forty years. The danger may be much reduced by the use of respirators, and by the employment of a blast of air to carry the dust away from the grinder into an a])propriate exit. Not all metallic dust is as irritating as that given off in cutler^-- grinding, and in some occu])ations in which it is given off even more abundantly, there is no noticeable tendency to phthisis, although, perhaps, the subject has not been investigated with sufficient thoroughness. In the operation of bronzing in the manufacture of show cards, Christmas cards, and the like, the br(Hize powder, which, under the microscojic shows sharp angles, is applied to the pattern, printed in sizing, by means of a soft pad worked largely by hand. The dust adheres tenaciously to the skin and causes much local irritation, and is inhaled and causes catarrh of the upjier air-passages. In addition, the workers suffer from headache, bad taste in the mouth, anorexia, nausea, vomiting, and diarrheea, from absorption and local action in the alimentary canal. When the operations of dusting on and off are done by machinery, the evolution of dust is very much lessened. The dusts of many of the metallic salts produce more or less serious local effects, aside from the results due to absorption into the system. In the manufacture and use of potassium dichromate, for example, great irritation of the nasal mucous membrane is caused, followed by ulceratiou, which in most instances ends in perforation of the septum. 734 HYGIENE OF OCCUPATION. Ulcers are produced wherever the skin is abraded, and especially on the scalp, where action is ])roraoted by the scratching which the irritation calls forth. Xo local effects appear to be caused in the lungs. As an example of a calling in which mineral dust is given off in abundance, that of glass-grinding may be mentioned. This is much like cutlerv-grinding, in a general way, and the dust produced is nearly, if not quite, as sharp and irritating. In addition, the workmen are often subject to lead-poisoning, due to the use of putty powder con- taining 70 per cent, of lead oxide. It is as rare to find sound men among this class, as among needle-grinders. Gem polishers and potters belong in this same category. Stonecutters and quarrymen are exjjosed to coarser kinds of mineral dust, but their work being conducted in the open air or in open sheds, they are by no means so prone to diseases of the lungs. Some stone is much dustier than others, and hence may cause more marked effects. Mica dust is exceedingly irritating, and, like the sharp particles of glass and steel, prepares indoor workers for the reception of the bacillus of tubercu- losis. In the wall-paper industry, it is applied to obtain the effect of " frosting," and assists or is assisted in its action on the opera- tives by another very fine dust made of finely chopped or ground lambs' wool, which is applied to the pattern printed in size in much the same manner as obtains in bronzing cards. The workei^s are very prone to phthisis. Vegetable dust is of very many varieties, which affect the system with varying degrees of intensity. Ordinary wood dust appears to be quite innocent of injurious action on the lungs of carpenters, whose employment is very largely out of doors, and of cabinet-makers, who, on the other hand, work in confinement. Grain threshers, millers, and many others exposed to vegetable dust present no great evidence that their callings are markedly inimical to health. Certain others, how- ever, offer important and interesting facts, indicating that, either alone or as one of a group of influences, some of the vegetable dusts are as disastrous in their effects as some of the most irritant of those of metallic nature. Among the most unhealthy classes of workpeople are those engaged in cotton and linen factories. Cotton dust, or '' flue," is very irritant to the upper air-passages, and causes dryness of the throat, followed by cough and expectoration. In some operations, a sized cotton thread containing kaolin is used, and then the air is laden also with this very irritating substance. Flax dust, or " ponce," is even more irritating than cotton. In the linen factories of Belfast, which, according to G. H. Ferris,^ employ 30,000 persons, five-sixths of whom are women, the deaths from phthisis and other respiratory diseases have been shown to out- number those from all other diseases by about two to one. Among the women below thirty years of age, the death-rate from phthisis is three or four times as high as among women of the same ages engaged in other employments. In 1892, the phthisis death-rate reached the ^ Journal of State Medicine, March, 1895, EXPOSnilK TO /NFJ'XrnVh' MATTKIL [N DUST. 7.*55 enormoiiH luti^lil <•(" ll.l |)(i- 1 0, ()()(), ;ijr;iir)sf 11.0 for flu- wliolc nf En^Iiuid ;ui(l VViih^s, ;iii<< many houses in proj)(>rti()n to tiu^ ))oj)ulation. Workers in tohnccc) arc exposed not alont; to irritatinjr .'ind poisonouH (hist, but to fumes as well. 'I'hey an; nnich subject to nasal and bron- chial catarrhs and disorders of the di^cstivi; ai)paratuH and nervouH system. The women eni;aocd arc said to abort very commonly, on account of the death of the fictus. Many assert tliat the r»ccupation in itself is not an unhealthy one, and (hat it possesses certain advantaj^OH in that it renders the individual less susceptible to infective agents. As evidence of this, it is said that, during the great eholeia ej)idemic at Hamburg, in 181)2, there were but 8 cases of the disease, with 4 death.s, among the 5,000 cigarmakers there resident. Animal dust is given oif in the numerous industries in wliich wool, silk, feathers, fur, bristles, hair, horn, bone, shell, ivory, and other sub- stances of animal origin are used. These substances are irritating to different extents, as would naturally be supposed frf>m their verj' diverse character, some, as wool, feathers, and silk, resembling in action cotton and flax, and others, as shell, bone, and ivory, acting more like the mineral dusts. The operatives in woollen mills, a})pear, on the whole, to be rather less subject to phthisis than those engaged in the cotton and flax industries. Among the others of this class, those making brushes and buttons, especially pearl buttons, are regarded as taking greater risks than the rest. Most statistics of these industries are faulty and inconclusive. 4. Occupations Involving Exposure to Infective Matter in Dust. This class includes those having to do with rags, wool, horsehair, hides, and other materials likely to be infected. The importance of rags as a vehicle for infection has been much overrated, but the danger is, nevertheless, a real one, as the experience of paper-makers has often demonstrated. The only method of insuring freedom from infection through the handling of rags is thorough disinfection, a proc- ess involving an expense, it is asserted, much disproportionate to the results achieved. The most common disease connected with infected raw material is anthrax, or '^ wool-sorters' disease," the spread of which is often traced to horsehair, wool, and hides. Nichols ^ reported 26 cases of this dis- ease as occurring in one curled hair flictory in three years. Ravenel' ' Second Annual Report of the State Board of Health of Massachusetts, p. 86. '^ Keport and Papers of the American Public Health Association, Vol. 24, p. 302. 736 HYGIENE OF OCCUPATION. collected 12 cases occurring in men and 60 iu cattle in three localities in Peunsylvania, during the summer and autumn of 1897. All of the men worked in tanneries, and all of the cattle were pastured in mead- ows watered by streams which received waste products from tanyards. The skins at fault came from China. According to Dr. S. Leduc/ imported horsehair is the most danger- ous material brought into France. The French market is su})plied by South America, whence it is shipped in bales compressed by hydraulic pressure. Unpacking the bales and sorting the contents according to color are alike regarded as dangerous. After being sorted, the hair is beaten, and in this process much dust is caused. It is then carded and spun into ropes. The precautions to be taken include removal of dust by special blower apparatus, perfect cleanliness, and great watch- fulness. Disinfection of the hair without impairing its commercial value or unduly increasing its cost is said to be impracticable. Naturally, the danger of infection by the spores of anthrax on hides, hair, and the many kinds of wools coming from countries where the disease is common cannot in any individual case be foreseen. From ordinary sheep's wool, the danger is slight, and from native wools is practically non-existent. When, for any reason, danger is appre- hended, M^orkmen with sores, cuts, or abrasions on their hands, arms, faces, or necks, should not be employed, ventilation should be thor- ough, and all precautions should be taken to prevent dissemination of the dust. 5. Occupations Involving the Inhalation of Offensive Gases and Vapors. This class of occupations includes a great variety of what are known as " offensive trades," having to do with organic matter largely of animal origin, such as tanning and currying, soap-making, glue-making, fertilizer-making, fat-rendering, bone-boiling, keeping animals, etc. While there can be no doubt that these offensive trades are a frequent source of nuisance to the community at large, evidence of injurious in- fluence on the health of those actively engaged and of the population in the immediate vicinity of the works is decidedly slender. There can be no doubt of the disadvantage of having such establishments located in the midst of thickly settled communities, and hence their supervision constitutes a most important part of the duty of public autliorities. The workmen are likely at first to suffer from nausea, vomiting, loss of a])petite, and headache, but these evidences of dis- turbance disappear within a short time, and do not recur. Contrary to general opinion, these occujjations not only do not appear to shorten life, but from such facts as are presented by the mortality statistics of occupations, it may be inferred that they con- duce to longevity, for, as a class, their average age at death is quite 1 Public Health Eeports, May 25, 1900, p. 1306. EXP()Sinii<: TO aunohmm. ATMosriiiinKi I'Iikssure. I'M hi^li. li, is liiirdly iicccssMry l.o j^k inlo llif .nc nddcd those of vitiated air, dnst, irritating fumes, and dampness, the, conse- quences may be very ^rave. Sndden chilling of the body and pro- longed exi)osnre without intervals of rest are es|)ecially to be guarded against. The woi'kmen of this class are commonly affeeti'd with catarrhal and rhenmatie, troubles, diseases of" the kl:i.li()ii.s <»(" lliis clasH briii^ ithitiit u varicly ol' sely interwoven with several of those already mentioned. For instance, a very large nnmher of indoor 0(v.n])ati()ns, carried on, pei'ha])s, under conditions ]ieenliar to them- selves, are at the same time sedentary in their natnre. The abnormal conditions brought about by sedentiiry life are those induced by a lack of general exercise of the body. This brings about a general sluggishness of the functions, which is ordinarilv most marked in those of the abdominal organs and heart. The eonscfjuences of too close coniiuement and lack of exercise are too well known to need detailed mention. Ordinarily, they can be expressed by the term "general debility." There is no particular reason why sedentary occupations should injure health, and it will be found in almost all in- stances of impaired function that the sedentary habit is not peculiar to the individual while at work, but during both work and leisure hours. The sedentary worker has the matter of prophylaxis in his own hands, and should take a reasonable amount of exercise daily, preferably in the open air. It is common to include brain-workers in this class, and to attribute to the sedentary side of their lives the con- sequences of overexertion of the mind. It must be remembered that activity of the mind has no shortening influence on life ; but abuse of the mental powers, and especially mental worry, conduce to headache, insomnia, and general breaking down of the nervous system and of the general health. PROPHYLAXIS IN GENERAL. In what has gone before, it will be noticed that the disastrous effects attributed to occupations are in very large part due to non-observance of the ]>rinciples of general hygiene, and chiefly to inattention to that most important sanitary measure, perfect ventilation. It will have been noted that in Groups 1, 2, 3, 4, 5, and ti, the conditions which bring about impairment of health may be reduced very largely by a con- stant supply of fresh air. With proper attention to this matter and 740 HYGIEyE OF OCCUPATION. improvement in the home and home influences, greater attention to the character and preparation of food, and a more general observance of the beneficial influence of active outdoor exercise, no very great differ- ences would be noted in the health of the various classes of work- people, and the expression occujjatioii dlaeaacs would lose whatever significance it now has. Employment of Women and Children. In view of the dangers and conditions incident to a great variety of occupations directly or indirectly inimical to health, it is of the utmost importance to protect the health of women and children by restricting them in the daily number of hours which they may give, and prohibit- ing their employment in distinctly dangerous surroundings, for women and children are more delicately organized and less resistant to weak- ening influences. Particularly should women be protected during the child-bearing age, so that they may be insured, so far as is possible, a hetilthy progeny. It hardly needs to be said that children should be protected most carefully during the period of their full development, in order that they may come to maturity in a fit condition to take on the responsibilities of the family. Inattention to the very great importance of conserving the health of women and children is bound sooner or later to result in degeneration, and this fact has received the attention of the law-making bodies of all, or nearly all, civilized countries. In this country, it is constitu- tionally a matter for legislation by individual States, in many of which not only is their physical welfare protected, but the moral aspects of trades as well receive due attention. As an example of such protective legislation may be given the fol- lowing rules, made by the State Board of Health of Massachusetts, to conserve the health of minors within the State. By reason of a law passed by the Legislature of 1910, the State Board of Health was given power to declare, from time to time, whether or not any partic- ular trade, process of manufacture, or occupation, or any particular method of carrying on such trade, process of manufacture, or occu- pation, is sufficiently injurious to the health of minors under 18 years of age employed therein to justify their exclusion therefrom. The processes named are given herewith : I. Processes Involving Exposure to Poisonous Dusts or Sub- stances : 1. Processes in the manufacture of white, red, orange, or yellow lead. 2. Processes in the manufacture of lead pipe, solder, and plumbers' supplies. 3. Cutting metal articles with a mixture of lead and tin, or lead alone. 4. Processes involving exposure to lead and the dust of plumbago in electrotyping. EMPfjOYMKNT OF H'Oy)//-;,V ANh dl I l.lillHy. 1\\ 5. I*r()r(!.s.s(!,s iiiv(»l\'iii^' (lie li:iiHlliii^ of" wliilc lend or lr-;i(i tnoiioxidc (lit liMrj^cj in nildicr (";iclorics. 0. LcikI piiini LMMiidiiijr. 7. \jv\u\ workiiit;' in IIh' ni;iniil;ict nif of -toraM-c haltfric-i. 8. File (Milling' by IkiikI. \). 'rypcsctlliij^, clcaiiinjj; or liandlinM 1\|)c in jtrintiii;^ olliccs. 10. (JIazinir in pottery cstahli-liimnts. II. Processes Involvirifr Ivxposnrc lo 1 1 ritat in;: i)iists: 1. J'rocu'sses involving exposure to (lie dnsl of ^rapliilc in tli(! inaniiiact(n"(; of stove polish. 2. 'V\u\ oj)eration of bronzing in tlic lithographie business, and the conse(|neiit exposnre to bronze ])o\vder. 3. Cutlery i>;rin(lin their reports regardless of the facts, and without the disagreeable necessity of going from house to house for information only slowly obtained. Ignorance on the part of the person questioned is doubtless a more fruitful source of error than intentional misstatement. Many persons do not know their age, and give, therefore, only a guess, which is most commonly expressed in multiples of five and ten. more especially the latter. This tendency appears, in general, only after the twenty-fifth year, and is showTi graphically by means of the accompanving diagram (Fig. 108) by INIr. R. H. Hooker, taken from Xewsholme's VitafSta- tistics. Again, many data concerning the occupants of a house are 744 VITAL STATISTICS. given by persons not qualified to know ; thus, the returns for a whole laiuily may be based upon the statement of a servant not long in the place. Intentional misstatement is most common with regard to age and occupation, many ^^•ishing to a})ix'ar younger, others older, than they reallv are, and many being reluctant to state correctly the occupations of themselves and of members of their households, preferring, perhaps, to record others more " genteel " or important. Other wilful misstate- ments are due very commonly to that over-development of the sense of humor that disposes its unfortunate possessor to regard extravagant lying as the acme of wit. The intentional misstatement of age is more commonly a fault of women than of men. Women are prone to understate their age after Fig. 113. 60 70 NO. AT EACH AGE 'Al WJ\ l\ JL 1000 Number of persons in Tasmania living at each year of age, according to the census schedule; showing the tendency to cluster at round decennial periods. passing twenty-five; with men, the tendency is to add rather than subtract. After twenty-five, many women become sensitive, and give their ages as under that age, and do not progress for several years. This is shown statistically by the British census returns, from which it appears that the girls of 10 to 15 years of one census, who become women of 20 to 25 years of the next census, reach these latter age periods without suifering any loss in number through death and emi- gration ; l)ut, on the contrary, with an augmentation, while the women of 20 to 25 years, who become 30 to 35 years old at the next census, show a very great diminution in number. Thus, as shown by Dr. Farr, the Registrar-General, in 1841, the number of girls of 10 to 15 years was 1,003,119, and in 1851, tl>e number of women of 20 to 25 years was 1,030,456, or 27,337 more, while the women of 20 to 25 years in 1841 numbered 973,696 and yielded in 1851 only 768,711— a loss of 204,985. It is inconceivable ESTIMATI'll) I'OI'tJLATION. 71-', that, tli(» loHHCH amoTi^ tlu; y<»uii^;('r j^nmp, y coriipari- Hon of th(! nstiiriis of any two coiiMcciitivc! siihscfjiKiut cnnnicratioiiH. Cluldrcn'H ajijcs an^ vciy (lotninonly ovt!rstiitc (iontitry jIIh- tri(!l:H (Voni wliidi liicy orininiiliy sprang; and a^^-iin, iimlcr (lie eoii- (JitioiiH ol)laiiiiii;j, in ciowdcfl conimunilies, men wear out, mon- rapidly than women. In (lie pi»|tnlalion a( l:ir<:;c, males are more nnmcroUH than AMiiales. A.\fv. (lis(iMl)iilion lias a, very impnrlani beariiifi; on tiic dralli-rate, Hincu, aH i,s vvcill Uiiown, tlu; lii^liest, deadi-rates, so far as af^e is ef)n- ccrncd, occur always in tlie earlier aj^c periods. 'J'liercfore, the prepon- derance of individuals of one and aiiotlua' age period haw a very great influence in demonsiraliiio- ap|>ai(n( dilTcrences in salubrity of different localities, wlusn the actual sanitary conditions are identical. With such agreement in sanitary conditions, a community which includes a much larger proportion of young (children will show a larger death-rate and a smaller marriage-rate than another in w hidi the population i.s made u|) more largely of young aihilts. In consecjucnee, it is necessar}-, in instituting comparisons between two localities, to take into accoinit (and make corrections therefor) the differences in age distribution, and to reduce the res]X'ctivc j^opulations to a common standard. Registrars' Returns. — Returns concerning births, marriages, deaths and causes thereof, and cases of infective diseases, are made to h)cal authorities, such as boards of health, and city or town clerks or regis- trars. In conjunction with census returns or estimates of population, they reveal the sanitary and sociological conditions obtaining from week to week, month to month, and year to year, in any community in which they arc made. Through tlicm we are enabled to watch the death-rate from all causes and from any one cause, the amount of pre- ventable disease, the probable fluctuations in populations, and other facts of interest concerning communities and groups thereof. They convey information as to sanitary conditions, and suggest wherein improvement in various directions is possible. The individual facts must, of course, be accurately observed and stated. This is particularly true of causes of death and distribution of infective diseases. The importance of proper groupings is well shown by the worthlessness of the lax returns not infrequently observed. For example, it is not unusual, especially in the older tables, to find " di'opsy " standing side by side with " heart disease," " kidney disease," Bright's disease, and other general or vague terms. The value of the aggregate facts depends very largely upon the length of time during which they have been g-athered, since only with the lapse of time can comparisons be instituted and the influence of temporary conditions eliminated or minimized. They must be suffi- ciently numerous to yield correct averages, for the larger the number of facts, the smaller the fluctuations caused by individual units ; and, conversely, the smaller the number, the greater the influence of single units, and the greater the chance of error ; or, more definitely stated, accuracy increases as the square root of the nmnber of units. Thus, 748 VITAL STATISTICS. 400 units will yield but half the error of 100, aud 900 will yield but a third. In no way, perha])s, ean the great iiifiueueeof individual eom- poneuts of a small aggregate and the small inliuenee of the unit when the aggregate progressively increases be better illustrated than by the daily Huetuatious in the comparative standing of a number of athletic organizations, such as ball clubs and bowling clubs, in competition among themselves for a ])rize or championshij). In the beginning, single events mav cause entire rearrangement, aud the Huctuations are wide and the curves most irregidar ; then, as the number of events increases, the fluctuations are less abrupt and the changes in the curves are gradual. In order that statistics may be useful, they must admit of compari- son with similar ligures obtained in other years and also at other places. But correct deductions can be drawu only when the conditions are at least apparently the same or when there is but one essential difference. One may not, for example, compare the death-rate of New York for the winter of 1898 with that of Detroit for the summer of 1875, and expect to obtain thereby information of value. In order to measure the full influence of any one important condition, the other conditions must be in agreement, or it must be possible to make correct allowance for any degree of divergence. Again one must not ignore the effect of temporary local conditions, such, for example, as an accident in a small community whereby a number of persons are killed at once and others die later from the effects of their injuries. The death-rate- of that town for that year would be abnormally high, and the sanitary condition of the place might be made by figures to appear much inferior to that of an adjoin- ing one where sickness and death from preventable diseases are much higher all the time. Marriage -rates. — Statistics as to marriage vary considerably from year to year, according to various circumstances, and especially with changing conditions in the prosperity of the general population. The rate is commonly greater in cities and towns than in country districts, not that country-bred people are less inclined to marry, but because large numbers of them are attracted to populous centers after arriving at the wage-earning age, aud there they marry. The marriage-rate is usually expressed as so many per 1,000 of pop- ulation ; but this is commonly open to objection, in that it may convey false impressions concerning inclination or disinclination to assume the new responsibilities, and also concerning the communal prosperity. Here, the importance of the population constitution as to age periods and sex is very clear, for in a community made up largely of old per- sons, young children, and domestic servants from without, the number of marriages occurring among the marriageable element might be very considerable, and yet the rate per 1,000 of population would be low. Therefore, a more instructive method of expression would be a state- ment of the rate obtaining among those of marriageable age. Again, the number per 1,000 of population does not admit of proper compari- i{iiLTii-n.\Ti':s. 740 son of (llfTrrciii c-ornrrmiiitics in tliis |»;iil inilnr, mile-- (licir |)<)|)iil;itl oC youths and maidens, the tinu^ comes when ;in iiini.^na! amoiinl of man-ia;_M-;il)I(; material becomes available, and the rate at onc(! advaiic<-s. A period oC nmisnal increase in the rate, from whatev(!r cause, is connnonly followed by a correspondinir decline, just as bitsiness pros- perity and depression arc marked by re<:nl;ir waves ; but the general trend is nmnistakably toward a diminntion. I'or nearly thirty years, a very gradual decline has obtained in nearly all highly civilized cf»nn- tries. That more women marry than men, sounds ])aradoxiea], 1>ut it is, nevertheless, true ; for men are more prone than women to second and third marriages, and statistics show that the tendency of widowers to marry spinsters is nuich more marked tlian tliat of bachelors to marry widows. The age at whi(^h marriage occurs has a very important bearing on the natural increase of population, since whether a woman marries early or late in the child-bearing period, determines, other conditions being the same, the extent of fruitfulness and, more particularly, the interval between successive generations. Statistics indicate that, among the native-born of this country, particularly in those parts longest settled, and in Great Britain and other countries in which the highest degree of civilization has been reached, the average age at mamage is steadily increasing. This has been attributed to an intelligent selfishness, 'ending to defer the assumption of responsibility for the maintenance of others, thus insuring an unrestricted enjoyment of the fruits of labor ; and to the wider opportunities for profitable employment of women, with consequent lessened dependence upon marriage as a means of support. Birth-rates. — Statistics as to births are expressed in the same manner as those concerning marriage ; namely, as so many per 1000 of popu- lation. This ratio is known as the crude birfh-rafe, and conveys no information concerning the proportion of women of the child-bearing age who have added to the population. Here, agjiin, a more accurate and instructive method of expression might be based upon a comparison of the number of legitimate births with the number of married women below forty-five years of age, and (^f the number of illegitimate births with the number of single women of the same limit of age. Under 750 VITAL STATISTICS. any system, still-births are not inchuled in either the births or deaths, although they are cert i tied. Birth-rates naturally vary very greatly in diiferent commimities, the same as marriage-rates, and for the same reasons. Ordinarily, they are higher in cities than in the country, and during and immediately iulldwing periods of prosperity than during times of depression. A higher rate iti to be expected of a manufacturing and commercial center than of a purely residential town, >vhere a large number of unmarried domestics, employed by the well-to-do and rich, swell the population and lower the rates of l)oth marriages and births in the manner already mentioned. In the latter case, the married inhabitants may be unusu- ally prolific, and the birth-rate, expressed per 1000 of married women below forty-tive, would be very high ; yet, the crude birth-rate would be low. So, in comparing two communities in respect to births, accuracy demands that they shall be reduced to a common basis. The higher birth-rate in cities and large towns is due to the greater proportion of women of child-bearing age, the higher marriage-rate, and the earlier marriage age that there obtain among people of the lower classes. Since the proportion of deaths in the earliest years of childhood is very high, it follows that a high birth-rate is always associated with a high death-rate ; but at the same time, a high birth-rate implies a large proportion of married persons in the full vigor of life at that age period which is associated with a low rate of mortality, and thus the influence on the death-rate is more or less corrected. A continued high birth- rate necessarily implies a large proportion of growing children who, year by year, swell the ranks of the reproductive. A low birth-rate, by causing a relative increase in the proportion of persons of the age periods of low mortality, may bring about a low death-rate ; but if it continues long enough to bring the population to a high average age, it will be succeeded by a raj)id increase in the death-rate due to diseases of advancing years. The birth-rates of many countries, like the marriage-rates, have for some years shown a steady decline. This is due somewhat to the in- creasing average age at marriage, which reduces the period of repro- duction, but largely to artificial restrictions and economic considera- tions. The great decline in the birth-rate of France has attracted widespread attention, and has become the subject of grave concern to the authorities and other thinking people of that country. A hundred years ago, \nore than a quarter of the population of what are known as the Great Pc vvers was French ; to-day, notwithstanding the marked disin- clination of that people to emigrate and seek new homes, the propor- tion has fallen to about one-eighth. In 1891, according to census returns, of every hundred families, 22 had but 2 children, and 24, but 1 child, apiece. The decline in births is not due to poverty, for it is among the poorest there, as elsewhere, that the largest families are raised. The same influences appear to have been in operation for some years in England and Wales, where, since 1876, when the birth-rate was 36.3, DEATII-liATI'lS. 7r>l it ("(ill |)f()^r(!Hsiv<'.]y in lw(!iil,y yciu-H to 2().7, and hIiowccI in \\\c hiHt ycui's of Ui(! <'cntiiry a nior'c slrikinj^ dcciv-asc llian in any of licr ff»nntry of I^jiiropc. Ill our own coiiiitry, aiiioiiH- the (|(;.i(;(;n(iant.s (jf the orij^inal colonistH and cailici' iiiiiiiinriuitH, tlic same dwsliiie is most (ividfiif. Wlicn-aH in colonial tiiiK'S and in (lie earlier years of nalional iiKlependeiife, farni- lieH of a do/(Mi, (ir((;en, aii1 percent, of the total births. The crude birth-rate was 27,77. Death-rates. — Death-rates are ealeiilated in the same way and ex- presses! ill the same terms as birth- and marriage-rates, that is, by mul- tiplying the number reported by 1000 and dividing the product by the population, or by dividing the reported number V)y the number of thousands of population, the result in either case being the rate per 1000 of population, This is known as the general, gi'oss, (»r crude death-rate, and is affected by so many factors that, without careful study and due allowance for disturbing influences, it may prove to be a very faulty index of the health of the people and of the sanitary con- dition of the place. When used as a basis for comparison of different places, the death-rates must first be corrected by making careful allowances for differences in age, sex, and race distribution, and for abnormal influences. Influence of Sex. — Sex exerts a decided influence, since, in general, females live longer than males and their mortality is lower at all age periods, excepting from the tenth to the twentieth year. So, of two places equal in sanitary and all other conditions excepting .sex consti- tution, the one with the greater proportion of females will have the lower death-rate. Except in newly settled places, there is, as a rule, a preponderance of females over males, although everywhere the births of males exceed in number those of females, the preponderance being the result of the higher mortality that obtains among males, except at the age periods above mentioned. Influence of Age. — The influence of age distribution is far greater than that of sex, since, for example, the mortality per 1000 of chil- dren under 5 years of age is more than ten times that of persons between 5 and 25, and more than six times that of adults between 25 and 45, Thus it may be seen that the greater the proportion of popu- lation belonging to the earliest and latest periods of life, the higher will be the death-rate. One would expect, for example, a higher mortality in a community made up largely of elderly people or young children than in one unusually rich in young adults, or, to reduce the 752 VITAL STATISTICS. matter to its simplest terms, in a foundling asylum or retreat for the aired than in a collecre for voung; men. iBfluence of Race. — To a certain extent, racial peculiarities have an influence on vitality, and especially on susceptibility to certain diseases. Thus, the negro is far less prone to some and far more susceptible to other morbid influences than the white. As between difl'ercnt peoples of the same race, tlie diflerences are not so wide. In those parts of this country where the negro population is considerable or preponder- ant, this influence can never be disregarded, and, indeed, it is com- monly the practice to calculate separate rates for the whites and for the blacks. According to Hoffman,^ the mortality of whites and blacks in ten southern cities, including Baltimore, Washington, Rich- mond, Memphis, Louisville, Atlanta, Savannah, Charleston, Mobile, and New Orleans, during the years 1890—94, was expressed as 20.1 and 32.6, respectively. This divergence, it is pointed out, would be still greater, if correction were made for age distribution. The excess of negro mortality obtaining at all age periods is espe- cially noticeable in the earlier ones. Thus, in 1890, in Washington and Baltimore, the death-rates of negro children under 5 and between 5 and 15 years of age were more than double those of white children of the same age periods ; in the age periods from the fifteenth to the forty-fifth year, the rates for both races naturally diminish very much, but the ratio is nearly the same. After the forty-fifth year, the dif- ference begins to be much less, but the excess is always with the negro. As instances of the differences in white and black death-rates, the following are presented : f December, 1899, White, 23.49 ; Colored, 28.59 New Orleans ■ ■ ■ \ January, 1900, " 28.28; " 44.80 Baltimore March, 1900, " 22.50; " 39.60 November, 1899, " 13.42; " 22.30 December, 1899, " 15.00; " 29.38 -January, 1900, " 17.90; " 30.60 L Whole vear, 1900, " 17.48; " 33.42 Atlanta Whole "vear, 1900, " 11.59; " 19.50 Augusta, Ga " '" 1899, " 10.50; " 31.00 5 wks. ending Jan. 6, 1900, " 15.70 ; " 33.23 Charleston ^ 4 " " Feb. 3, 1900, " 12.60 ; " 27.50 (, 2 " " Feb. 24, 1900, " 19.81 ; " 32.94 The difference between white and black mortality is believed to be due more largely to race degeneration than to sanitary conditions. In the North, the negro shows an excess of deaths over births, and holds his own only by influx of recruits from the South. According to Dr. Scale Harris,^ before the Civil War the negro death-rate in the South was less than that of the whites. For exam- ple, in Charleston, S. C, from 1822 to the beginning of the war the * Eace Traits and Tendencies of the American Negro. Publications of the Amer- ican Economic Association, New York, 1896. ' The Futuj-e of the Negro from the {Standpoint of the Southern Physician, Amer- ican Medicine, Sept. 7, 1901. INFLUI'lXdl': OF DFSSITY. 7.)') avcni^f! (!(';illi-r!it(! oC IIki whiles was 'J,~).UH, uihI of Uic l)l;u;ks 2 l.Oo ; but from I .SflT) (,o I M!) I, alllioii^li llic rate was hut nhghtly hi^hf-r iu the case of the vvliilcs (20.77), it hnd ncntly «louhh;(l (4'i.29) with the l)lu(!k.s. r^roui what has hcfii said, it iiiiisl he cviflcnl th.il ciiHic dcath-ratcH (jauuot h(! I'clicd upon as a hasis ol' uiortalily (Mtuipariscui of" two phux^, uulcss th(! n'S|)('(;(,ivc populafious ai'c in suhsfaiilial a^rccuioiit in aj^e, race, and s(!X (Muistilulion, nor (or conipiirisoii oi' dn; (;on latter, 2(12, whih; in London the rat(! was hnt 151). The chief fiictors in I he eansalion of lii^h infant mortality are prcmatnre births, heredily, inlemperan(;e, early marriages, neglect, carelessness, i<2;uoranee, improper food, nnsanitary surroundings, indus- trial conditions, illegitimacy, and, perbaj)s, infant life insurancx;. The immediate causes are (!hie(ly inanition, diarrh(eal diseases, measles, whooping-cough, and other infective diseases, and viohiuce. The influ- ence of prcimature birth, heredity, neglect, carelessness, ignorance, and unsanitary surroundings needs no elucidation. Industrial conditions figure largely in the neglect of infants, since mothers in employment return as soon as possible after confinement to their work, and entrust their offspring to the care of older childnin and others, by whom they are improperly fed and looked after. During pregnancy, also, the woman remains at work up to the last posbii)l(> moment, so tliat her absence is limited to that period during which she is absolutely in- capacitated. The age of the parents has much influence on the vitality of infants, those of mothers under 20 dying off appreciably faster than those of others between 20 and 30. Between ?>0 and 35, the vitality of the offspring is still greater ; but after this age period it begins to decline. The first children of very young fathers also are, as a general rule, weaker than tiiose begotten later. To this influence of the parents' age, conjoined with that of ignorance and inexperience, may be attributed the excessive mortality which obtains among the first-born. Illegitimacy has a very great influence on the chance of survival to even the early period of childhood, for the infant is in an unfavorable position as regards care and home surroundings from the beginning. Abandoned by the mother to the care of whomsoever may be willing to accept the charge, or " farmed out " among persons whose interest in its welfare is wholly financial and subject to innnediate decline on the cessation or tardiness of payments, it has even less chance, perhaps, than when kept at home, an unwelcome addition both to the family circle and to the expense account. Infant insurance is generally believed to be an influence in diminish- ing the amount of care and solicitude for the health of the very young, ^ These figures are taken from a comnuinioation from Dr. S. W. Abbott. Secretary of tlie State Board of Health of Massiichusetts. on " Infant Mortality in Massachusetts." Journal of the Massachusetts Association of Boards of Health, December, 1S9S, p. 13-L 756 VITAL STATISTICS. and, therefore, has been the subject of considerable legislation, by which the maximum amount of the policy is kept at a low figure, as, for instance, the actual expense of burial. Whether insurance has more than an insignificant bearing, cannot be determined by trustworthy statistics. Beyond doubt, the most fruitful single cause of high infant mortality is improper feeding, due partly to the necessity of supplying an arti- ficial substitute for brciist milk and partly to ignorance. The breast- fed infant, carelessly looked after, has a far better chance than the bottle-fed more carefully tended. The former receives its natural food at a uniform temperature and practically sterile ; the latter is fed upon another kind of milk, differently constituted and of a different degree of digestibility, which, under the best of circumstances, is com- paratively rich in ordinary bacteria, and is administered at different temperatures, sometimes very hot, sometimes cold. AVith lack of care, the danger is increased, for the milk may be stale and dirty, and act as the vehicle for the exciting cause of cholera infantum, which is respon- sible to a greater extent than any other morbid condition for the deaths in mill towns of infants whose mothers are employed in the various industries. Besides dirty and stale cows' milk, a variety of cereal and sugar substitutes are provided, which may or may not be digestible and nutritiotis. Ignorance of what is proper for introduction into an infant's stomach is responsible for much infantile mortality, even when breast-feeding is followed. Who has not seen fond, but ignorant, mothers, in public conveyances, keeping their infants quiet with bananas, seed cakes, cookies, and other food materials unsuited to a digestive system which can have difficulty enough with milk alone ? It seems unlikely that such practices are restricted to the time spent in travel, when consid- eration for the comfort of strangers suggests the avoidance of fretting and crying. Death-rates of children under five years of age are expressed in the same terms as infantile mortality, that is to say, as the proportion of deaths per 1000 children of that age period. High and Low Death-rates. — In the absence of any unusual general unsanitary condition or of unusual prevalence of epidemic diseases, an abrupt rise in, or a very higli, death-rate is not infrequently only apparent, being based upon an underestimated population. A very low death-rate is always open to suspicion, although sometimes, as in newly settled communities with a very high proportion of young male adults, for a limited term of years, it is perfectly ])ossible and natural. A rate of 15 per 1000, for example, in large cities, is so low as to suggest that the population has been very much overestimated. Within recent years, the authorities of a rapidly growing Western city noted with great pride the gigantic strides in the estimated population, and were naturally much elated to find that the death-rate based thereon entitled the city to a position in the first rank of the cities, lai^ge and small, of the whole world. The census of 1900 dispelled the illusion, CORRKCTfON OF IU'lATU-llATES. tor the population Ii;hI Ix'cn jrrosHly cxii^^^cnilcfl, ;iiii| ilic ;i((ii;i| (Ic-itli- rat(! w:iH (soinparalivcly liij^li. I)(iM(Ji-riii(!S as low as 10 ;uily, sanitary administration, and general sanitary condition, but discrepant as regards the distribution of the sexes, age periods, and race, may show very different death- rates, perhaps magnifying the salubrity of the one and exaggerating the unhealthiuess of the other, it becomes necessary to have some method of bringing them to a common basis. In the matter of race influence, the best plan is to separate the statistics absolutely, having one set for the white and another for the colored population, and to compare white with w^iite and negro with negro. The method commonly recommended for correcting according to sex and age is the one in use in the oflfice of the Registrar-General for England and Wales ; this may briefly be described as follows : The mean annual, death-rate of the country for each sex at each of the eleven age periods, namely, below 5, o-lO, 10—15, 15-20, 20—25, 25-35, 35-45, 45-55, 55-65, 65-75, and 75 and upward, during the last preceding ten years, is obtained and multiplied by the number of those of each sex at each corresponding age period in the temtory under consideration, according to the returns of the last preceding 758 VITAL STATISTICS. census. Each product thus obtaiuetl, divided by 1,000, gives the cal- euhited number of deatlis for the respective sex and age periods. These 22 results, added together, represent the calculated number of deaths for the place in question in one year. The total calculated number of deaths, divided by the number of thousands of population or multiplied by 1,000 and divided by the population, gives the i^tan- dard dcdth'-ratc. The next step is to obtain a factor for correction, by determining the ratio which the standard death-rate of the place bears to the death-rate of the whole country. This is obtained by the rule of simple propor- tion, the second mean being unity. The recorded death-rate for the year, multiplied by this factor, gives the corrected death-rate, which will, therefore, be above or below the recorded rate, according as the factor is above or below unity. By dividing the corrected death-rate by the death-rate of the whole country, and multiplying the quotient by 1,000, the comparative mortality figwe is obtained; that is to say, the number of deaths which Mill occur in the same number of the local population as, in the general population, will yield 1,000 deaths. Classification of Causes of Death. — In the registration of causes of death, a certain amount of error is inevitable, for several reasons. In the first place, even the most competent practitioners are not infallible in diagnosis, and it is not always possible, when one pathological state is complicated by the advent of another, to determine which was the actual cause of the fatal termination. Next, the nomenclature of dis- eases is still faulty, although many of the sources of confusion have been removed by the adoption of the international classification ^ of the causes of death, through which it is hoped to secure uniform and com- parable statistics of the causes of death for the whole world. Again, the true cause of death frequently is misrepresented intentionally for private or family reasons ; thus, apoplexy, instead of suicide, and peri- tonitis, when the actual cause of the peritonitis is criminal interference. Lastly, it is sometimes the case that no cause whatever is assignable, even after careful autopsy, and, obviously, such cannot be classified. With the existence of an indeterminate amount of error, it follows that caution should be exercised in comparing results representing a series of years, and allowances should be kept in mind with changes in nomenclature, when drawing deductions from what has been described as the classification of the more or less reliable guesses of a large num- ber of more or less skilled observers. Registration of Sickness, if it were possible, would afford a far more efficient index of the sanitary condition of the j^opulation than the registration of deaths, which gives us simply the number of cases of sickness which ended fatally, but no idea of the duration thereof or of the number of persons temporarily incapacitated. A disease ordinarily regarded as fairly dangerous may prevail very extensively in a mild form, and be attended by a very low death-rate, and, again, may exist 1 This classification can be obtained by applying to the Bureau of the Census, Washington, D. C. Ml'! AN DUliATION OF rJFK. 7 f>U to a leHsnr o.xivnt, l)ui in !in iiiiiisdaily Hc.vo.rc. form, witli u lii{.'li propfir- tioii of (!i,l;ilil,ics. Miiiiy (lis(;:i,scH, .-i^raiii, urc Icinponirlly dihiililiiitr and oflcn widely |»n;v:il<'n( , l.iit, pl.-iy ;i ,sni:dl |.;i(f in mortality nturiiH. Toii.silliti.s, for cxunipli!, is rcsponHihlc for nin
  • loyed to denote and measure the duration of life, a prohlem with which the science of vital statistics is largely engaged. One of the most falla- cious indications of longevity and sanitary condition is the ^fmn arje at Death or Mean Lifefliiie, which is the sum of the ages at deatli divided by the number of deaths. This is unreliable, because it fluctuates very widely, according to age distribution ; for in a community containing a larg(> proportion of children and in which the birth-rate and, conse- (pieutly, the infantile mortality are high, the average age at death will be lower than in another, equally healthy, in w^hich these conditions do not obtain. Hence, it can only be employed with any degree of safety where the population constitution is uniform in all respects, and when the observations are carried along over a long period. The mean age at death, not of a few hundreds or thousands of individuals, but of an entire generation of population, is necessary to show accurately the mean duration of life, and this is determined only by means of life tables. Probable Duration of Life signifies the age at which half of any num- ber of children born will have died, so that they have equal chances of dying before and after that age. It is also called the vie probable and the equation of Life ; but all of these terms are ill-chosen, for eveiy possible duration of life has a certain probability, which may be deter- mined by life tables. Mean Duration of Life is another ill-chosen term with which the last- mentioned is often confounded, but which has an entirely ditlerent meaning. It is meant to express the probable duration of life from the date of birth. In an ordinary population, subjected to the usual disturbing intiuences of migration, it means present age plus the prol>- able length of life after passing a given point, and is called commonly the expeetation of life or rnean a/tcr-lifetime. It is a term, which, by reason of its indefiuiteness and looseness of application, it would be well to eliminate alti>i>'ether. 760 VITAL STATISTICS. Expectation of Life, or Mean After-lifetime, is the average number of years which an individual at any given age will continue to live, as shown by a life table. As applied to whole communities, it is the mean duration of life of a generation of individuals from birth to death, and is regarded as the only true measure of the health of entire popu- lations. Like others which have gone before, it is an unfortunate exjiression tending to confusion. " The term does not imply that an individual may reasonably expect to live a given number of years. The excess of those who die late is distributed among those who die early, ' those who live longer enjoying as much more in proportion to their number as those who fall short enjoy less of life.' Thus the expectation of life has no relation whatever to the most probable life- time of any given individual." (Newsholme.) "Expectation of life is an incorrect term : the time which it is expected a person will live is the time which it is an even chance he will live ; it is the vie probable of the French, and is correctly expressed by ' probable lifetime.' The after-lifetime can only be the same as the prolxible lifetime on Demoivre's hypothesis — that the surviving form an arithmetical progression. The term ' expec cation of life,' first used by Demoivre, is correct, on that supposition, which is, however, in itself quite erroneous. The idea iatended to be expressed by ' expec- tation of life ' is the viean time which a number of persons at any instant of age will live after that instant : it is the French vie moyenne ; and this technical idea is strictly and shortly expressed by nfter-lifetime, a pure English word, formed on the same analogy as after-life, after- times, after-age, after-hours. The after-lifetime of men at the age of 30 is 33 years by the English Life Table : 33 years is not the precise time probably that anyone of that age will live, but the average time that a number of men of that age Mdll live, taken one with another. Age -f- after-lifetime = Lifetime. At 30 this is 30 -f 33 = 63, the average age which men now aged 30 will attain. At birth this is + 40 = 40 ; when lifetime and after-lifetime are the same thing. " The lifetime simply, without the addition at a given age, will serve to express in one w^orcl what is improperly called the expectation of life at birth ; thus the lifetime of males in England is 40 years, the lifetime of males in Manchester is 24 years. Those who, from habit, prefer ' expectation of life,' can always substitute it for after-lifetime ; from the use of which, in this paper, no ambiguity can arise." (Dr. William Farr, Eighth Annual Report of the Registrar-General, p. 279.) Life Tables. — A life table, according to Dr. Farr, is an instrument of precision. " It may be called a biometer, for it gives the exact measure of the duration of life under given circumstances. A life table represents a generation of men passing through time ; and time under this aspect, dating from birth, is called age. In the first column of a life table, age is expressed in years, commencing at (birth), and proceeding to 100 or 110 years, the extreme limit of observed lifetime." 1JFI-: TAIUJ'X 761 Til order to eoiisiriif!!, ;i lidr; lahl'-, i( is essciili.-il to li;iv<', jih rii;it<;rial, a lvii()\vl<;(l}:;(! oCtlu' size of the |)o|»iilalioi) and its age and h-x rc(jiiir(;rn(!iit, ;ui(l persons of" (:()iis))ic,iioii.-ly low mciiliil cajKirily may n;- ([iiin; Miiicli tnorc. It is jrf^ncrally accopUtd, liovvcivcr, that for tli<; repair of waste, tli. Against rain and eold wiixls, iinpi-rnu^bhi niatiTials aH'ord very grrjat protection. Wiixls act in two ways to (;hill the; body : by cf>n.stant removal of th(! air in (jontac^t with th(^ body and warnn-d by nuison of contact, and by hastening evaporation of tlie moisture within the .sul>- stancc of the ch)thiug. Heat Conductivity. — Materials vary widely in their power of he^it conduction. Atiiong the; textihis, linen and cotton are by far the be„st conductors, and wool lUv. j)()on!st ; l)ut since the conductivity of a g;ir- mcnt is governed mainly by the looseness of texture, it follows that the same amount of a good conductor, loosely woven, may be warmer than wool woven very closely. But the fabrics made of the best con- ductors are commonly very closely woven, and of wool are of varying degrees of looseness. Hygroscopicity. — Fabrics hold moisture in two ways : first, by retaining it in the interstices between the fibers ; and, secondly, by absorption directly into the substance of the fibers. The moisture held in the interstices gives the sensation of dampness or wetness, and may be largely removed by pressure, as in wringing; that absorlx^i into the fiber may be very large in amount without giving any sen- sation of dampness, and it cannot be expelled by pressure. The latter is known as hygroscopic moisture. Materials of animal origin are more hygroscopic than those from the vegetable world, and while they absorb water readily, they part with it more slowly by evaporation. Thus it happens that a person, sweat- ing to the same extent and under the same general conditions, feels less sensation of chill on resting from his exercise or work when clothed in woollen, than when his dress is linen or cotton. In the latter instance, the moisture is held more largely in the interstices, and the garment may be distinctly wet, and then adheres to the skin, which, as evaporation proceeds, becomes chilled through ra])id abstrac- tion of the heat required in the process ; whereas, in the former, the evaporation is gradual and the chilling much less perceptible or unnoticeable. But here, again, a hygroscopic material, very closely woven, may be incapable of holding as much moisture without im- parting the sensation of distinct wetness, as one of a loosely woven substance of low hygroscopicity. Materials. The materials employed in the making of clothing come mainly from the animal and vegetable worlds ; from the former are derived the 772 PERSOXAL HYGIENE. wools of various kinds, silk, furs, feathers and down, and leather ; from the latter, the principal derivatives are cotton and llax (linen), and, of lesser importance, straw, hemp, jute, and rubber. Wool. — AA'ool of various kinds is yielded by a number of different genera of animals. That in conmionest use and to which the name is very generally restricted is derived from the sheep. Other kinds include mohair from the Angora goat ; kashmir, or cashmere, from the Thibet goat ; camel's hair and alpaca, from Auchenia pacos, a cameloid ruminant of South America. But the terms mohair, cash- mere, and alpaca commonly refer to cotton and sheep's wool imitations containing no trace of either of these more expensive wools. Under the microscope, the fibers of wool are seen to be cylindrical and translucent, and covered with small imbricated scales which, like those of a fish or the feathers of a bird, run all in the same direction. Fig. 114. Woollen fibers. They are sharpest and smallest, and hence most numerous, in the finest sorts ; as many as 2800 and as few as 500 to the inch have been counted respectively in the best and very inferior kinds. They give to the fibers the tenacity with which they cling together when woven, and the readiness with which, when wet and subjected to pressure, as rubbing or wringing, they mat together and cause shrinking of the fabric. They are shown in Fig. 114, which is drawn from a specimen of fine Saxony crewel. Woollen goods, being poor conductors and containing much enmeshed air, are the most valuable of all textiles for general purposes in all climates, and particularly in those in which abrupt wide changes in temperature occur. In very hot climates, they are inferior as outer garments to cotton and linen, which, being better conductors and re- flectors, assist more in keeping the body comfortably cool. But for un- dergarments, wool is much better as a protection against chilling after sil.K. 77.'} active (!X(!r(!iH(!, on uocoiint of ils \\yiir<)i\r.()\)\c proy)f'rt,ics ; the vaynir from tlu; Ixxly is coiMhtiiscd and absorbed, and tii<; licat, wliicli lK;<:oinf,H latent wli<;n iJic nioisliin; is vaporized, in set free, and the evajKira- tion from tlu; I'ahric, to ihv. (;xt(:rnal air |)roceod.s nlowly and without the ohillinn; AXvri observed when on(! sits in c\\\\^\u^ wet eotton or linen, wiiicili feels cold in j)ro|)ortion to the rapidity with whi*-h it dric^-. Woolhwi fabries are niiieh subject to adulteration with cotton and other eheaj)er materials. What are known as Hanneiettes are very commonly made wholly of (sotton or with a very small perc<' from tli(! :uiim,'il world; iind iiny ;ilt(iM[)l on llw |):irl of an in«-x[M'- ri(!n(',(Hl |>('rson lo (lcU;rmin(! tlic p('Vi'ci\i;\^<- of hoddy, since only plain goods of a solid eoior yield fibers all of (jne shaarl-gray silk stockings, colored by repeated baths in a solution of zinc chloride. It was shown that a large amount of the salt was present in the finished goods when packed for the market, and that the danger therefrom by absorption was very great. A serious case of poisoning by anilin black is quoted by Cartaz,^ from a report of Landonzy and Brouardel to the Academy of ^ledicine of Paris. A child of seventeen months became suddenly unconscious and apparently asphyxiated, and, although restored, remained very ill for forty-eight hours. Then the brother of the child and a number of other children were seized in the same way. All of the victims wore shoes which gave off a peculiar penetratiug odor, and were found to * Lancet, December 6, 1898. *La Nature, August 4, 1900. 778 PERSONAL HYGIENE. have been dyed with aniliu black. Animal experimentation proved that absorption of this by the skin is favored by heat and moisture, which conditions are present in a tightly laced shoe, and may bring about alteration of the blood corjiuscles and asphyxia. Another case is reported by Besson/ of a child of six years, A\ho, after wearing a pair of new shoes during the forenoon while at play, became cold and cyanoscd in the afternoon, but Avas relieved by heat and stinuilants Avithin twenty-four hours. The shoes had been pol- ished Avith a preparation Avhich had a distinctly nauseating odor, and contained 91 per cent, of anilin, Laurent and Guillemin- report still another, in which six children, all of one family, were seized, after wearing new shoes upon which the anilin polish had not completely dried, with sudden symptoms of poisoning, which included pallor of the face, bluish discoloration of the lips and nails, dilated pupils, headache, vertigo, albuminuria, great muscular weakness, slow pulse, slight convulsive movements, and unconsciousness. Kecovery occurred in from one to three days. It is commonly believed that arsenic in dyed and printed textiles is present as an accidental impurity of various anilins, but this is far from being the truth, since white arsenic itself is used in several processes for the purpose of adding brilliancy to the colors. Thus, in the so-called arsenite of aluminum process, the dye, dissolved in acetic acid or water, is mixed with acetate of aluminum and white arsenic in glycerin, and the mixture is employed in printing the pattern ; next, the printed fabric is subjected to moist heat, and the anilin, in combination with the arsenite of aluminum formed, is fixed in the fibers in an insoluble form. Selection of Clothing. The properties of the various materials used in the manufacture of textiles have already been given in some detail, and further con- sideration of underclothing and outer garments, beyond a word of caution against unnecessary weight of clothing and undue constric- tion of any part of the body is, therefore, unnecessary. In the matter of constriction, no part of the human body is so abused as the foot, especially that of woman. Boots, shoes, and stockings should fit the foot, and there should be no such thing as the agony which many people expect as a matter of course in the process of " breaking in." The toe should be neither pointed nor cut square, and the whole sole should follow the natural outline of the foot. The sole should project a reasonable distance from the upper, in order to give firmer support and increased protection to the soft parts from contact with loose stones and other objects. The heels should be low and broad High heels are worn, not for comfort in walking, but to in- crease the height of the body and diminish the apparent length of the foot. For purposes of successful deception, they take about equal rank ' Journal des Sciences medicales de Lille, 1901, No. 10. '■^ Journal des Praciciens, March 2, 1901. HKlJCariON OF CLOTIIINd. 771i with liair (" (Ih' imisrlcs of llic li-{r, ini'l !i variety of other ul)ii(>nM;ilili(s. 'I'Ik' Ii<m- ninnity, not all of those whos(! systems an; invaded become stricken with the disea.se, even thoniih they may receive the sanu; dose of the organisms. Of a do/cn children exposed at the same time and for a like period to a pre-existint;- v\\^q of .scarlet fesc^r, perhaps one, or tliree, or six, or none at all may be .seized ; of a hundred consiimerH of typhoid-infected milk, ])erliaps a dozen may ])e infected ; in an entire community of a hundred thousand jx'rsons, all drinking water from a common sup|)ly, a few hundreds or thousands may be stricken with cholera in the event of extensive specific ])ollution of the supj)ly, the rest of the population esca])ing with no .symptoms whatever. The reason for this lies largely in diflf'ering susceptibility: one person may be very susceptible and others wholly resistant, regardless of the extent of exposure or of the number of exposures : some may resist a few exposures and later succumb. Some may be exposed without any resulting invasion. A\ hether or not a given individual will be attacked may depend also upon the number of organisms which enter his .'sys- tem ; for while a few disease germs may be overcome and destroyed, a larger dose may secure a foothold and cause injury. On the other hand, what might be an overwhelming dose to one may be doubled and trebled, and yet be ineffective against another. Susceptibility is influenced by a number of conditions, including age, race, family ])redisposition, cold, fatigue, etc. A person who to-day is insuscej>tible may, a few days hence, acquire susceptibility through any one of a number of causes which bring about a depressed condition of the system, such as lack of proper food, exposure to cold or extreme heat, exhaustion from overexertion, mental disturbance, loss of sleep, abuse of alcohol, overcrowding, mechanical injury, and constitutional disease. A person may carry virulent pneumococci in the respiratory tract and not be affected, because of the natural defensive properties of his cells ; he may for the .>^arae reason escape an attack of Asiatic cholera, although large numbers of the specific organisms have gained access to his intestinal tract ; and yet, in the foi'mer case, a bad cold, and in the latter, a derangement of digestion, may overcome his defence and he falls a victim. An individual who is insusceptible to the influence of a particular pathogenic organism is said to be immune, or to enjoy inmi unity. Im- munity may be either natural or acquired, and acquired immunity may be active or passive. Natural immunity is the inherent ability to resist 782 INFECTION, SUSCEPTIBILITY, IMMUNITY. infectioD when the system is invaded by disease germs : for example, the insusceptibility of man to hog cholera and rinderpest ; of carnivora to tuberculosis ; of rats, dogs, and birds to anthrax ; of horses and cattle to typhoid fever and cholera. In these and in many other instances that might be given, the respective organisms, on being introduced, find themselves opposed by conditions which are inimical to their existence and multiplication, and they soon succumb to the hostile influences. This form of immunity is, however, not always absolute : it can be overcome in various ways. Thus, while birds are naturally imnume to anthrax, it has been shown that certain species may be rendered sus- ceptible by starvation or cold ; and rats lose their immunity to the same disease when they are fed wholly on a vegetable diet. Acquired immunity is, as stated, of two kinds : active and passive. Active acquired immunity follows recovery from an attack of a disease which, except in rare instances, occurs but once in the same person (as yellow fever, scarlet fever, smallpox and chicken pox) ; or from a disease of an allied nature (as immunity to smallpox after cow pox) ; or it can be induced artificially by the injection of increasing doses of bacterial toxins or of bacteria which have been killed by heat or dimin- ished in virulence. It can be acquired not only against diseases, but against certain proteid vegetable poisons (ricin and abrin) and snake venoms (rattlesnake) ; but it cannot be acquired against the numerous alkaloidal poisons. In but few diseases does one attack confer a lasting immunity ; and even in these, second and even third attacks may some- times occur, but their severity is, as a rule, much diminished ; thus, smallpox and measles. Witii some diseases a single attack confers a temporary immunity (e. g., pneumonia, la grippe, and diphtheria), but subsequent attacks may be of equal or greater severity. With other diseases, notably malaria, immunity may be acquired ^Vith such extreme slowness that increased susceptibility may appear to become established. Passive acquired immunity is that which is brought about by the injection of serum obtained from the blood of an animal that has acquired an active immunity, the serum containing specific anti-bodies; and it may be acquired also through the milk of an immune mother, the anti-bodies being secreted therein. Passive immunity is acquired rapidly and with practically no danger or discomfort, but the protection conferred is only transient. On the other hand, active imnumity is a matter of much less rapid appearance, but its protective influence is much more lasting. The tolerance which the system develops toward a specific poison becomes established as a result of certain processes concerning which we have practically no actual knowledge. While we know that certain means employed produce certain results, the various changes which occur within the system during the process are matters concerning which thus far we can only theorize. We are met at the outset by the fact that protoplasm is a substance of extraordinarily complex composition, which defies exact analysis, and the products which it elaborates are, (50 far as we know, of equally compleJi nature. It combines with and KJlULICll'S Til 1:011 Y. 783 18 acted upon by vurioiiH matorinls, whicli, ncfonliiif^ to llicir nature, promote or di.stufl) nictjiholi.srn ; c. //., niilritivf rnatt<'rs and toxinw. It i.s with tli(! latlci- tliaf problems of immunity have to dral, for idtlioufj;!) under some eondilions pro(opl;ism is by them destroyed or di,sturb(!d iti its I'lmetions, under others it i- ;ible not only to witliHtand their inlluenee, but (o develop antajionislir- produets, whieli overeome them (iomplelcly and thus |)r(;vent disease or pivirnote reeovery. All oin- kuowleda;*' of what oeeiu-s in the establishment of immunity and all the lliei'apeutl<'al appliejitiouH based upon this knowled^^e we owe to animal ex|)erimenl:ilinn ol ;in exeeedin^ly ingenious and intercHting nature, whi(^h has j:;iven rise to several th(;ories. Of these, the "reten- tion theory " of Chativeau and the "exhaustion theory" of Pasteur have h)iig since been disproved and possess now merely an historical interest; and the only ones which have withstood the t«'st of time and investigation are the "humoral theory" of Ehrli('li and the "cellular theory" of Metschnlkofl', both of which will be considered below. EHRLICH'S THEORY. Ehrlich's lumioral or side-chain theory, which had its inception in 1897, explains first the action of the soluble bacterial toxins and their antitoxins, then deals with immunity against these poisons and the bacteria which secrete them, and finally embraces the far more com- plicated question of immunity against those pathogenic organisms which liberate no soluble toxins, but bring about results which in some way are dependent u]>on the actual presence of the bacterial cell. The analogy between l)a('teriolysis and haemolysis has made the experimental work much less laborious, since the latter can be employed to solve the problems of the former. Toxins and Antitoxins. — In their interference with metabolism, different species of jiathogenic bacteria act in very different ways ; they produce different kinds of poisons whose actual nature is as yet but little known, and these interfere with the cell functions, each in its own manner. They appear to possess certain definite chemical affinities, like the flir simpler inorganic compounds ; they are precipitated by certain agents and redissolved by others ; they combine with other complex compounds and form more or less stable inert substances. Whether the bacteria are within the tissues elaborating the poisons and sending them to distant parts of the body, or are grown in artificial culture media outside, the poisons which a given species produces appear to possess the same properties, so far as they can be studied. Bacterial diseases may be divided into two classes : (1) those in which the infective agents are localized and produce their effects through soluble poisons which they secrete and send through the system in the blood stream ; and (2) those in which, whether localized or not, the infective agents act not through soluble poisons, but in some manner depeudent upon their actual presence in the tissues and yet not explainable in all cases by mere mechanical presence. These bacteria, however, contain 784 IXFECTIOX, SUSCEPTIBILITY, IMMUNITY. poisons united Avith their protoj^lasm — intracellular toxins, some of \vhich have been separated and subjected to carefid chemical analysis; and it may be that they become effective on liberation from the bac- terial cells when these die and are disintegrated. Indeed, we know that, in the autolysis of cultures of B. ti/phosus, a toxin is liberated into the culture medium ; and Vaug-han and Wheeler' have obtained, in soluble form, highly poisonous material from the cell substance of colon, typhoid, and anthrax bacilli. That the last-named organism produces an intra- cellular poison was shown first by J. W. Vaughau,^ all prior investiga- tion having given negative results. Intracellular poisons have been demonstrated also by Detweiler' [B. prodigiosus, B.violaccus, Sarcina lufca, and Sarcina aurantica) and by Gelston.' As examples of the first class may be cited dij)htheria and tetanus ; and of the second, the true septicaemias, in which the bacteria are dis- tributed generally, and typhoid fever and pneumonia, in which the bacteria have a selective affinity for special organs. It is likely that in the establishment of immuuity to both classes of disease, the general principles of the process are the same, although the details may diifer. In the diseases of the first class (diphtheria and tetanus), acquired immunity depends upon the formation, within the system, of substances termed Antitoxins, which, while having no power to destroy the causative bacteria themselves, neutralize their toxic products (toxins). In the immunizing process a very small part of what, under ordinary circum- stances, would be a fatal dose of the specific toxin, or a small dose of a weakened toxin, is given subcutaneously to an animal, and this is re- peated at intervals of a few days. After a time, the dose is increased, and eventually the animal is capable of receiving without injury a nor- mally fatal dose, and is then possessed of an active acquired immunity. If now the animal be bled and its serum be injected into another, it will be found that the latter can resist infection by the organism which pro- duces the toxin, or that if infected before treatment, the injection will exert a curative influence. In 1890 Behring made this discovery as to diphtheria, after he and Kitasato had found it to be true of tetanus. In 1891, Ehrlich, working with abrin and ricin, found that these toxins treated in vitro with the serum of animals immunized therewith became neutralized and incapable of causing injury. The protection transferred from the actively immune animal to the other is passive acquired immunity. The serum of the immunized animal differs from that of the normal in that it contains the specific antitoxin, which is a substance believed, with good reason, to unite in a definitely chemical manner with the specific toxin to form an inert compound. How the antitoxin is formed in the system is an interesting question, which Ehrlich explains in the following manner : The bacterial toxins have special affinities for special cells, and if they are introduced in ^ .Journal of the American Medical Association, September 3, 1904. ^ Transtictions of the Association of American Physicians, 1902. ^ Ibidem. * Ibidem, Kiinijaii's 'nii.oiLY. 785 HiifUcii'Dt ;un()iiM(,H those, cttlls iirc; destroyed ; hut if" not, tliey are merely (Jiiriiiij^ed by IIk; union of tli(! toxin with ecTtiiin utoni-^M-oufw of the eell (or wiiieh it })OHsesseH tlie H|)(!f!i;d .'iflitiity. Thr- iitorn-j^roiij) with which th(; toxin unites is eiUled n, llccfjtlor or iSi/lr-r/inln. 'J'h(; cell, |)einji; d;un;ii;('d by the loss of tiiis portion of" its Hnhst;UK;e, proceeds to r(!|)iiir its(!l('l)y rephuting this rec(!ptor ; hiil, f"olh)Vvinj^ Weigert'.s law of 8njK!re,oni|)(!ns;i(ion, it |)ro(hi(!os un (sxcchh of nieeptors, whi(;h, not being needed, an; ciist out inio \\h\ blood slreani, where they an; f"n'e fo unito with any ("i-esli portions of" toxin with which they may efunc; in e its poison molecule has no cell upon which to work, and is consequently unable to produce harm. The receptor thus acts in two ways : it may attract the toxin to the cell, which thus may suffer, or it may protect the cell when it is no longer an integral part thereof. (See Fig. 118.)' It has been shown by Ehrlich and others that a specific proteid toxin differs in one very important respect from alkaloidal and other common poisons, namely, that the latter are possessed of no haptophore groups with which they can form chemical combinations with the body cells or with substances derived therefrom. A dose of morphine, for exam- ple, no matter how frequently it is repeated, is incapable of causing the ^Figure ll.'-! and the succeeding figures in this chapter are purely diagrammatic ; and in- order tliat no erroneous conception nia_v be formed concerning the various sub- stances which thev represent, shapes have been adopted which are not likelv to sug actual cellular or molecular forms. 50 786 ISFECTIOy, SUSCEPTIBILITY, IMMUSITY. formation of a substance with -which it can unite to form an inert body, although it can establish a tolerance for larger doses ; in other words, no morphine antitoxin can be produced. If one should attempt to immunize an animal against morphine, the serum of that animal when mixed with a fatal dose of mor})hine would not deprive the latter of its power to poison another, as will an antitoxic serum mixed in proper proportion with a lethal dose of its corresponding toxin. Ehrlich says that the term toxin should be applied only to those toxic products of metabolism with which, by animal experimentation, one can obtain a specific antitoxin. As examples of true toxins may be cited those of diplitheria and tetanus, snake-venoms, abrin (from the jequirity bean) and ricin (from the castor bean). In the case of any one of these, a reaction occurs in the body, whereby the toxin becomes bound firmly to the cell, instead of entering into loose combinations which are easily broken up, as in the case of alkaloids. It must not be supposed that the so-called receptors or side-chains are concerned merely with toxins and antitoxin formation. The cell protoplasm is an exceedingly complex substance and the cell is some- thing more than a mere molecule : it is made up of many very complex molecules. It is unfortunate that attempts to explain immunity with the aid of diagrams lead many to conceive that the words cell and mole- cule are in a sense synonymous. The smallest possible drop of water consists of many molecules, all of the same character ; but a cell is an aggregation of complex molecules of diverse natures and functions. The cell possesses certain atom-groups (receptors, side-chains) with aiSni- ties for nutritive materials which come within the range of their chemism, and through them it fixes within itself that which it needs for the carrying on of its functions. It possesses affinities also for the proteid toxins, which are believed to be similar to, though less complex in composition than, the nutritive materials. Doubtless, it possesses many other atom-complexes with other functions ; and doubtless, also, the number of each kind is such that the destruction of a few does not necessarily mean the death of the cell, which under favoring conditions may proceed to make good its loss by processes of repair. The side- chains which are concerned in the fixation of toxins and which are cast oif into the blood stream as antitoxin are denominated by Ehrlich TJniceptors ov Receptors of the first order, being of the simplest kind and possessing a single bond of attachment, the haptophore group. Other more complicated receptors than these will be considered presently. That the union of toxin with antitoxin is a purely chemical process, is believed by Ehrlich and most other investigators, and as proof are cited a number of facts. Thus, when a toxin is mixed with its cor- responding antitoxin in proper proportions in a test tube, it becomes neutralized and is then incapable of acting injuriously any longer. Like acids and alkalies, the two can be titrated against each other. Again, as with most chemical reactions, the union of the two is has- tened by warmth, and occurs more readily when concentrated solutions are employed. It appears, however, that with tetanus toxin, at least, I'liiiiLicirs 'I'lii'.onY. 787 tli(' union willi luit-iloxiti is ai lirsl, ;i sonicwliiit lor).so u."Hr)riation, wliif-li can l)(! (lisiiiplcd ; and tiiat, as titnc j^ocs on, tlu; combination hccorrifs fixed. Tliis lias been wliovvn in an iiitorcHtiii}^ cxiioririiont by A. Wa»- scrinaiin, vvlio, Iiavinfjj f'onnd thai a niixtiin! of" Ictaiins toxin and \i\\\xu".i- |)iii;-l)i'ain cirnilsion possc-sscd tio toxic, action for ^'iiinca-ftifr-, wiiilc niixttir'(!s willi cninlsions of oilier oiLfiins ol" tli(; hanie anitnal retained tlieir power, concluded that (lie toxin has u Kpccial aflinity for tlic n-Wn of the central iicrvoii.s systcitn, and thai these contain nornmlly the anti- toxic; side-chains, which arc the same as those existing in the serum of an imnunii/ed anitnal. Jt is known that tli(! tetamis toxin reaches the cells of the central nervous systcuii thron 5r»" ( /. ( I.JI " V.) or allowed t<) Htaiid lor a week or inoic. This j)ro[>- c.vty was awailn-d hy JJiieliiior, in 1892, to tin; iii(l(ieiiee oC HiihstaneeH wlii(;li ho. calhid A/cxlim (now known an ('oinjilrnicnlyy The living animal has the, same power when the organisms aro injeeted In not exeessive nnnihers. Tims, one can injeet small do.-es of ehoh-ra organisms indt a <;nin(a-pi<; willioiit eauHing any injnry, and if the dose bc! gradually increased the animal heeomcH so resistant that it can with- Kland a single dose of many times the ainonnl that, in an nntn-atcd animal, wonid inevitahlv oanse death. In oth(;r words, the animal becomes immune to cholera ; its .system has undergone changes which enable it to destroy the specific organism in ordinarily overwhelming doses. If its scrum is injected in very small amounts into other guinea- pigs, llui latter also ae(juire the same imnnmity. It was shown by Pfeiiler, in 18!)-1,that aniiuals thus ai'tificially ininuuiizecl could receive without harm into their peritoneal cavities doses of cholera germs, which within 20 minutes would be dissolved by the peritoneal exudate ; and he asserted that the result was due to a substance different from JiiK^hner's alexins and produced in the body during the j)rocess of immunization. He showed also that a non-imnmnized guinea-j)ig, which would be killed by the intraperitoneal injection of a certain dose of cholera germs, could withstand the same if some heated immune serum (thus depi-ived of its eonijilement) were introduced at the same time ; and he concluded therefrom that the immuniziug material, although it had been exposed to heat, had not lost its bactericidal ])roperty, and that it had influenced the organization in some way so that it could destroy the bacteria. I^ater, it w^as discovered by Bordet that the bactericidal power can be restored by the addition to the heated serum of a small amount of normal serum from anou-immunized guinea-pig, thus she^v- ing that, for the solution of the bacteria, two substances are required, one of which (complement) is a normal constituent of the blood, and the other (immune body) a substance called forth by the immunizing process. While the perfectly fresh immune scrum, like fresh normal serum, has power to dissolve cholera organisms in vitro, so, too, on keep- ing, it loses it ; but the addition of some fresh normal serum or of some peritoneal exudate restores the property ; that is, it reactivates the inactive serum. This was shown by jNIetschnikoff and by Bordet (in 1896) prior to the beginning of experimental work in haemolysis. It is thus evident that, with both normal and immune serum, two .sub- stances are involved in the process of bacteriolysis : one, the comple- ment, is thermolabile (destroyed at 55° C.) ; the other, the immune body, capable of conferring immunity, is thermostable (resistant to heat). Haemolysis. — The abandonment of transfusion of blood was aiused so long ago as 1869 by the fact that marked destruction of the red cells was found to occur, as was sho'^ni by the ha?moglobinuria which followed the (Operation ; but transfusic^n can be practised without injury between animals of the same species and between certain animals closely 790 INFECTION, SUSCEPTIBILITY, IMMUNITY. related, as, for example, between the dog and the wolf; but not between unrelated species, as the dog and rabbit, or the dog and horse. Rabbit serum will dissolve the red corpuscles of the horse, ox, pig, monkey, and man, but not those of the hare ; guinea-pig serum acts against the corpuscles of rats and mice, but not against those of rabbits ; human corpuscles are dissolved by the serum of the horse, monkey, ox,- sheep, etc. Although transfusion was abandoned at the time and for the reason stated, the hemolytic action of blood serum attracted but little attention until 1898, when it Avas shown by Belfanti and Carbone that the blood serum of horses which had been treated with injections of rabbit blood was poisonous to rabbits, while that of horses not so treated had no such property. Later, Bordet announced that guinea-pigs, after a similar course of treatment with rabbit blood, yield a serum which will dissolve the red corpuscles of a rabbit with great rapidity. The same solvent action was found to be exerted by the serum of other animals treated similarly with alien blood, and it was shown that it is a specific action ; that is, that it is exerted (with certain few exceptions) only against the red corpuscles of the particular species whose blood is used for injection. In other words, if species A is injected with the blood of species B, A's serum will acquire the property of dissolving B's corpuscles, but not those of species C or D. This destruction of blood cells is known as Hcemolysis, and the agents which bring it about are termed Hcemolysins. The nature of the h?emolytic substance has been the subject of much investigation, which has proved that the solution is effected not by one single constituent of the serum acting alone, but by two acting together, each being powerless in the absence of the other. Ten years previously, in 1888, Nuttall had pointed out that many normal serums possess the property of destroying bacteria, and that this ceases on exposure of the serum to a temperature of 55° C. (131° F.). Investigating haemolysis, Bordet found that in this process, too, the property disappears at this temperature, but can be restored by the addition of a very small amount of serum of another animal of the same species, that has not been subjected to treatment ; that is to say, of a normal animal. Later, it was discovered that an inactivated normal or immune serum can be reactivated, not only by normal serum from the same species, but also by that of other animals not necessarily nearly related. Thus, goat serum, which is hemolytic for guinea-pig and rabbit blood, loses this property on being heated to 55° C, but gains it again on the addition of horse serum, which itself has no action whatever on rabbit blood. It was clear, then, that at least two substances are required in haemolysis; one unable to resist exposure to 55° C, but existing in both normal and immunized animals, and the other, resistant to 55° and even 65° and 70° C, and existing only in the serum of those immunized. To the former, common to both kinds of serum, Bordet applied the term Alexin, invented in 1892 by Buchner for the bacteri- cidal substances which Nuttall had shown to exist in normal blood ; to the other, found only in the serum of the immunized animal, he applied ll/KMOI.YSIS. 71)1 tlio U'vm f^nhsfd/iice HcnsihUiwiiricc. Tlicsc Icrnirt ami riiar)y oIIkth that hav(! hrcii coined as siil)sl iliitImi) [)i(j)ar(;H tin; rcfl corpii.stjK.'.s through M»rne nicaus of its ovvu, fixing itscK", Mccordinji; to I^hilirh aud Morjrcriroth, in th(! r(!(l ct^lls Ihcinscivc^s. 'V\\(: (;oiu|)h;in<'iit is not only lf;.s.s n-.si.stant to heat than tlu; ininiiiiic body, but is less persistent on Htonige of the serum. Invcstiiration by JOhrli(!h and Morj^enroth of thr; power of normal blood seriun to dissolve ali(!n oorjuiscles deraonHtrated that this, too, does not dcjx'nd upon a sint^de sul)slancf, as was maintained by Konu!, but ujjon two substan(;es acting together, as had Ix^en proved to be the case with immune serum. The second substance analogou.** to the immune body is now known as the JnUrhodii, Go-hdveen, or Zwischciikorpcr. Ehrlieh and Morgenroth proved also that a normal serum whi(^h will destroy tiu^ red cells of more; than one animal sj)ecie8 possesses an interbody for each spe(ties, and dillerent complements as well. A hemolytic serum is intensely poisonous to the animal spe<;ie8 whose blood has been em])loye(l in its produ(^tion, injections of a few cubic centimetres (causing destruction of the blood cells in corpore. It acts like a toxin, and similarly an artificial immunity to its action can be produced, an antihsemolysin being formed instead of an anti- toxin. In attempting to discover the relationship of the active constituents of hemolytic sernm to the blood-cells which it dissolves, and to deter- mine upon what its specific action depends, Ehrlich and Morgenroth had recoui'se to a most ingenious experiment, by which they proved that the immune body combines with the corpuscles, and that the combination is of a chemical nature and resists attempts to break it apart.^ The specificity of the union was shown by the fact that the combination does not occur when blood is used other than that for which the serum is hemolytic. They proved also that a similar com- bination between the blood corpuscles and complement does not occur, and that the immune body possesses two affinities ; one, very strong, for the corpuscle, and one, less strong, for the comjilement. Since the latter, as proved, has no combining affinity for the red corpuscle, its action must be dependent upon the interposition of some agent which has ; and this is the immune body, with its two combining groups. Therefore, it is plain that the function of the immune body is to enable ^They destroyed the complement of a goat senim tliat was haemolytic for sheep blood by heating it for a half-hour at 5o° C, then added 4 volumes of a 5 per cent, mixture of sheep blood in 0.75 per cent, salt solution, and after letting the mixture stand for 15 minutes at 40° C. they caused all the corpuscles to separate as a sediment by centrifu- gation. That none of the inmiime body was present in the supernatant fluid they proved by adding to the latter some more sheep blood and normal serum (containing complement) and tinding that the corpuscles were not dissolved, as they would have been in the presence of the immune body. The sediment of corpuscles which had com- bined with the immune body was mixed with normal (complement-containing) serum, and after a time the corpuscles were dissolved. 792 INFECTION, SUSCEPTIBILITY, IMMUNITY. the complement to attack aud dissolve the corpuscle, and this it does by acting as a coupling-link between the two. Its r6le is the same in bacteriolysis, binding the complement to the bacterial cell in the same way. Diagrammatically, it may be shown as in Figure 119. It will be seen that the same relations exist between the immune body and the blood corpuscle or bacterial cell as between a toxin and its antitoxin. Both the immune body and the antitoxin possess haptophorcs, which fit respectively the receptors of the blood corpuscle and the haptophore of the toxin. They are analogous products — free side-chains. c Fig. 119. ^ywoto;(ic group -COMPLEMENT H»-pt"opbore -Corr)plemcT7topbile qroup LIMMUNE BODY _V~^_ -Cy^o p b i I e c/Youp J^eceproYs The importance of the study of the phenomena of haemolysis lies in the fact that analogous, if not identical, processes occur in bacteriolysis ; and it happens, too, that experiments with blood cells are more simple and convenient in several respects, among which is the fact that they can be carried out in vitro, and they are also better adapted to accuracy. Although the study of bacteriolysis antedates that of haemolysis by ten years, it is to the latter that our knowledge of immunity is especially due. The side-chain theory, which originally applied to the production of specific antitoxins and was then extended to the formation of specific bacteriolysins and haemolysins, was finally broadened so as to apply as well to the production of all other antibodies of whatever nature caused by the introduction of any substance which can combine with receptors in the body and bring about the overproliferation and setting free of the same. It is not to be supposed that the body cells are of such simple structure that they have affinities for only nutritive mate- rials, toxins, alien bloods, and pathogenic bacteria. As has been pointed out, the living cells are enormously complex aggregations of exceed- ingly complex molecules, and Ehrlich holds that the atom-complexes have a great diversity of functions and combine with whatever sub- stances, and only those, for which they have receptors ; and these sub- stances naturally must possess atom groups (haptophores) which can link themselves to the cell receptors. The haptophores of the im- munizing substances are quite distinct from the atom complexes which COMI'LEMICNTS. 703 liavc fuiH!tioiial j)oculi;iriti('H ; for example, flie ioxophorc gronjj.s (jf toxins, and the zyinoplion; groups of" leniiciits. Illustrative of the (toinplcx natiin; of body eclls and of iIk- mnlti- plieity of ;itoin {j^ronps vviiiitli tlu^y jkihschs, may he eit<(| the pioduetion of vaiMous oflicr eyloloxins.' Thus, th(! injcelion of" alien s|M'rmato/^)a causes the ])r(KhH;tion, in the serum of tiie animals injeeted, of f^fK-cific substances termed tSj/cniiof.o.vlnn, which have the prtwer to immohilizr', if tluiy do not dissolve, tlie spermatozoa of the species f"roni which they arc derived, and also to iiu'iiioly/e its red corpuscles. A^'ain, in the same way, a serum can he ohlaiiK^d by injection of ciliated epithe- lium from the trachea of the ox which will have a similar action on this form of cells, and this serum also is iKcmolytic (7rlrMolrixiii»). By injeetin<]^ material from the central nervous system, from the liver, from tile kidneys, from the mesenleric tz;l:inds, and from boiu; marrow, specific serums have been obtained which are j)oisonous respectively to tiie nerve cells (^Neurotoxins), liver substance {I[rpatotoxinn), kidney substance (^Nephrotoxins), and leucocytes (^Leucotoxhifi). Each of all these pos- sesses a thermolable complement (destroyed by exj)osure to 55° C.) and a thermostable imnume body. But this is not all. The study of the production of antibodies has gone much farther, and it has been proved that, proceeding in the same way as in immunizing animals against toxins, a variety of antibodies can be produced. Thus, by be- ginning with very small doses of specific ha?molysin and gradually in- creasing the amount of the injection, an antiha?molytic serum can be produced, which, when added to the hsemolytic serum, will inhibit the latter's action. Investigation has demonstrated the existence in anti- haemolytic serums of anticom])lement and anti-immune bodies, both of which are specific. In the same way can be produced antispermo- toxins, antileucotoxins, and even antibodies to these antibodies. An enormous amount of research work of a most complicated and ingen- ious nature is going on constantly, having for its object the solution of the many problems of immunity, and these few facts are given merely as examples, for a general survey of the subject in all its branches is beyond the scope of a work of this nature, particularly until a wider practical application can be made of the numerous discoveries. Complements. — The elements of blood serum, which, through the intermediation of the immune body, bring about the destruction of alieu blood cells or bacteria, are not ]iroduced as a result of an immun- izing process, but are normal constituents of the blood. As stated elsewhere, Ehrlich has demonstrated that the blood contains not one, but a multiplicity of complements, and that they may differ in their resistance to heat. Thus, the serum of a goat immunized with sheep blood lost, on being heated to 55° C, the power which it possesses normally to dissolve rabbit corpuscles, but was baemolytic for sheep ^" Cytoiorin is used for anv substance in serum, venom, or bacterial cultures, or of plant origin, which destroys cellular elements, either animal or vegetable. The haemo- lysins and other toxic substances which kill but do not dissolve cellular elements are included under CS'totoxins. also the bacteriolvsins (bactericidal substance, alexin)." Nuttall, Blood Immunity and Relationship, p. 14. 794 INFECTION, SUSCEPTIBILITY, IMMUNITY. blood until it was heated to 65° C. Most complements, however, are destroyed at the former tcmjiorature. The multiplicity of comple- ments is, however, a matter of disagreement between Ehrlich and Mor- genroth aud others, on the one hand, and Gruber, Bordet and their followers, on the other ; but the weight of experimental evidence ap- pears to be with the former, who maintain that a diiferent complement is required "to link itself to immune bodies that are specifically haemo- lytic for difierent kinds of blood corpuscles. Complements are believed to exert a sort of digestive fermentative action upon the cells (blood or bacteria) to which they are linked by the immune body. They lose this property, as a rule, when they are heated to 55° C. They are believed to contain two imjiortaut atom complexes : one, the haptophore, with an affinity for a similar group in the immune body ; the other, the zymotoxic group, is the functional (digestive) part. It is the latter that is affected by exposure to 55° C, the former still possessing the power of combining with the immune body and of stimulating the production of anticomplement when the heated normal serum is injected. Complements that have been deprived of their zymotoxic groups are analogous to toxoids, and are known as complementoids. An immune serum, while it acquires a large amount of immune body, does not, as a rule, gain any additional amount of complement ; and inasmuch as the two work together, it cannot exert its full power in test-tube experiments without the addition of a sufficiency of com- plement, which can be supplied in such experiments by the addition of normal serum. In the practical therapeutical application, however, of a bactericidal serum, the necessary complement may exist already in the blood of the patient ; and inasmuch as such a serum may contain many thousand times as much immune body as complement, it follows that a relatively small dose will be sufficient to furnish an enormous number of linking bodies to enable the complement of the blood to perform its office ; but, as will appear, there may be an insufficient sup- ply of complement for the attainment of the desired result, and in practice the deficiency cannot easily be made up. Moreover, an excess of immune body, as also will appear, may act to the disadvantage of the subject. (See page 803-) As to the source of the complements, there is considerable disagree- ment. By some they are believed to be secretory products of the leucocytes and of other kinds of cells, many of which have been shown to have phagocytic properties ; Metschnikoff believes that they are not secretory, but decomposition, products of the leucocytes ; Pfeiffer and others believe that the leucocytes are in no way concerned in their pro- duction, and Wassermann asserts that these are practically their only source. While the process of immunization appears to have no influence in increasing the amount of complement, it is doubtless the case that their amount in normal serum is subject to more or less fluctuation in the same individual from day to day under varying conditions of health IMMUNIC no DIES. 796 Fk;. VZO. COMPLE- riENT ANTICOMPLEr, EMT and (li.slm-bntHU' of ilic body Cimclioiis. Thus, Klirlicli and M()r{.M-iirolh h;iv(! proved (lie di.s;i|)|)(ai':MH;<; of coinitlcniciil in jxdhonin^ l>y J)Ii«)h- plionis, and Mctsc.lmikon" iLs diniimilion (ol lowing .suppuration. It in j)(),ssil)lo tlial, rcducisd Hisistance Lo iidcclion may dcfUTKl upon t\\e reduction of coinjjlcnicnt hy tlio HpontiUKsoiiH ])roduf;t.ion of anticom- plcnicnl, in iJu; system. Allliou^li (liis Kj)on(Mneous prodiwtion lias not yet been d(;monstral(;d, it lias been proved by Wassermann that the injection of anticomj)lement,s increaKcs HU.sceptibility to infection. Anti(!()mph'inent v.ux be produced (]}ord(!t) by injection of cf)mj(Iement (normal sei'um of another spe(Mes), thus causing the production of a serum which is antagonistic to ha-molysis and bactei-iolysis, .since the anticomplement pos.sesses a haptophon' ^rouj), which links itself to the corre.spondinfr group of the complement and thus prevents a similar union of the com- plement and immune i)ody. This action is shown diajj^rammatically in Fi 120. Except in those ciises in which the com- plements of the two species possess identical combining groups, the anticomjilcmcnts are specific bodies ; that is, they combine only with their specific complements. The union of complement and anticomplement is very firm, as has been shown by Bordet, who found that it caniiot be broken up by heat. Immune Bodies. — The immune bodies, believed by the Ehrlich school to originate through the saturation of some particular atom complexes (side-chains) of some par- ticular cells, are specific bodies ; for exam- ple, that which links complement to one kind of blood cell will not act for that of another species ; that \\ hich makes possible the destruction of a cholera germ will exert no action against the bacillus of typhoid fever. That they exist in one form and another in the system under normal conditions is generally admitted, for in the normal metabolism of the cells it is assumed that various substances — nutritive substances, for example — stimulate the over- production and liberation of side-chains, among which may be some that are identical with those which originate in consequence of the introduction of alien bloods, bacteria, and other foreign substances. Whether each immune body is a single definite substance or a com- bination of substances having special affinities for different materials is a matter in dispute, the former view being held by Bordet and Metschni- koff and the latter by Ehrlich and Morgenroth, who bring forward certain experimental proof of the correctness of their view. It has been shown that different kinds of blood cells possess some similar receptors, and that each cell appears to have these atom complexes in great variety, so that a given cell may be able to link itself to the receptor of this or that immune body and not to tliat of some other ; 796 INFECTION, SUSCEPTIBILITY, IMMUNITY. aud Ehrlich and Morgenroth regard the immune body of a serum as the sum total of its athnities for diiferent cells, each corresponding to one partial immune body. A particular khid of blood cell or species of bacteria introduced into an animal's system may or may not find corre- sponding receptors for each of its many different combining atom complexes or haptophores. If it should not iind them, then only a part of the possible number of })artial immune bodies will be produced by the animal. In another species of animal, other receptors may be, and are, present ; and in consequence the immune bodies produced by the two must differ to some extent in their composition, each containing certain atom groups or partial immune bodies that the other lacks, and each differing in similar respects from those produced by other sj^ecies of animals subjected to the same and to different stimuli. If Ehrlich and Morgenroth are correct — and the weight of experimental evidence appears to indicate that they are — the employment of bacteriolytiic serums made by combiuing a number of serums derived from different species of animals ought to give better therapeutical results than one derived from one species, and hence containing a smaller assortment of possible combining groups. The greater the variety of these groups, the greater the possibility for the human system to bring its complements into action ; and these cannot exercise their functions unless they find the necessary intermediary agents — the immune or partial immune bodies. Indeed, it appears certain that in many experiments with lysins a number of different immune bodies or partial immune bodies are concerned. Inasmuch as the atom complexes or combiuing groups of the molecules that make up the bacterial cell may not be absolutely alike in different races of the same bacterial species, it is reasonable to believe that an immune serum produced through the employment of one particular culture will not affect all different cultures of that organism equally. In fact, that is what often is seen in actual prac- tice : a bactericidal serum is active in a certain number of cases and of no value in others. Hence, as pointed out by Wassermann,^ the way out of the difficulty is to employ, not a single culture, but a number of different cultures of the same bacterium in the preparation of a serum, in this way securing a very large number and variety of partial groups. Such a serum Wassermann would call multipartial. In the same way that anticomplement can be produced by the injection of normal serum, so, also, can one bring about the formation of anti- immune body by injecting an immune serum into an animal in small and gradually increasing doses, after the method followed in immuni- zation. The resulting serum will contain both anti-immune body and anticomplement. Agglutinins. — It was observed so long ago as 1869 by Creite, and in 1875 by Landois, that the blood serum of an animal when mixed with the red corpuscles of many other species causes them to come together in clumps. In his experiments in haemolysis, Bordet observed that in a hsemolytic serum this property is increased ; that the agglutination ' New York Medical Journal and Philadelphia Medical Journal, October 15, 1904. A(j(;LirnNiN.s. 797 prnondcH tlu; Holiilion oC I Ik; ca-.Uh ; uiid tli.il \\u-. iiicrcM.sf! in a^^liitiiiiitiiif^ |tr()|)(!rly i,s s[)(!ci('ic, — llinl is t/» wiy, il i- iiicrcnsj-d wiffi r(')^\u-(:t lo the Isliid (»(' l)l(»()(| (•,(»i|)iis<;l('S llijil liiivc l)C('ii ciiiplriycd ill tlic |)nKH'f-s rif |)r()(liiy exposure to 00° C., and it may resist even 70" (J. ; and so a ha-molytie sernm whieh hfw been heated to tliat temperatnre, wiiiie i( loses its lia-niolylie profierty, is still enpahic; o(" eaiisinj:; a^'ulnt inalion. TIk; exciting canse of" its genesis is supposed to reside in tli(; stroma of the injected corpiiHclcfl. Aeeordinii; lo Stewart,' the injection of the stroma oi' an alien blood stiimdalcs {\u\ |)r()dnction of a;z<>;luti nation with whicih \vc are most familiar is that which is cmj)loycd as a means of diagnosis in susj)ected typhoifl fever — the Gruber-Widal n^action. The serum of a person ill with that disease, diluted with bouillon and mixed with a culture of typhf)id germs will cause the latter to clump together. This happens whether the bacilli are living or dead. The agglutinin may ])ersist in the system for many months or years after an attack of typhoid fever, suggesting a persistence also of the specific bacilli, which we know to be often the case, since they may be discharged in the urine continuously for many months after recovery. The bacterial agglutinins were studied first by Gruberwho concluded that in some way they affect the bacteria, so that they can l)e killed and dissolved ; but experimental evidence tends to show that they are not necessarily injured, and that, on the contrary, they can even continue to multiply, even though agglutinated. It has been shown by Bordet and MalkofP that the bacterial agglutinins and the haemagglutinins combine with the bacterial cells or blood cells in the same way as the go-betweens (Zwischenkorper) of normal serum. The agglutinins are comjilex substances ])ossessed of haptophores, which combine with haptophores in the blood cells and bacteria, and other atom groups which cause the clumping. The cells ujion which they act (blood corpuscles and bacteria) contain what is called ^'agglutin- able substance," which also is made up of at least two atom complexes, one of which is a haptophore, as mentioned above, and the other is sensitive to the atom group which causes the clumping. Thus, the phenomenon of agglutination is analogous to the chemism of haemolysis and bacteriolysis ; but the one is apparently not dependent upon the other, for haemolysis and bacteriolysis may occur without agglutination, and agglutination may occur without subsequent solution. Thus, dog serum will agglutinate but not destroy anthrax bacilli, and rat serum will destroy but not agglutinate them. ' American Journal of Physiology, XL, Xo 3., June, 1904, p. 250. 798 IXFECTION, SUSCEPTIBILITY, IMMUNITY. Ehrlieh reg-ard.s the ngglutinins as s])ecial products in an immune serum, analogous to the bactoriolysins and luemolysins. The atom complex that causes agglutiuation is very susceptible to the action of acids and other substances, and when it is deprived of its functional power, the result is the same as with toxins that have lost their toxophore groups : the agglutinin retaining its ha])to])}iore group is converted to an agglutinoid, just as a toxin becomes a toxoid ; it still can combine, but it cannot agglutinate. Precipitins. — If the serum of one species of animal be injected into an animal of another not closely related species, the serum of the latter will acquire the property of precipitating part of the proteid material of that of the former when the two are mixed together. For example, if we mix normal rabbit serum and horse serum, we observe no reac- tion ; but if we inject a rabbit with horse serum at proper intervals, after a time its serum will acquire the property of causing a precipitate when it is mixed with horse serum. The substance which is developed in this process of immunization and which brings about the reaction is known as a Precipitin. Precipitins are not wholly specific in their action. A serum obtained by immunizing with the serum of species A may precipitate the latter and also that of some other closely related species. This was pointed out first by Nuttaiy whose extraordinarily extensive researches, conducted with hundreds of difi'erent kinds of blood and involving the making of many thousands of tests, have been very rich in results valuable alike to students of zoology, physiology, and immunity, and also to those who have to do with medico-legal investigation of suspected blood stains. The use of these facts concerning precipitins in the detection of ani- mal flesh of various kinds has already been referred to on page 34 of Chapter I., where a method for the detection of horse-meat has been, described. This method has, however, its limitations. For instance, it is said to be difficult, if not impossible, to distinguish by this test between the flesh of sheep and that of goats. Precipitins have been found in certain normal serums. Thus, ox serum will precipitate that of man and also that of a number of other species, and the same is true of the serum of dogs, goats, and other animals. They have been found also in the serum of animals immu- nized with bacterial cultures ; these are known as bacterio-precipitins, and are specific for the culture filtrates of the germs employed and for solutions of the material within the bacterial cell. Precipitins, like agglutinins, are far more resistant to heat than the other immune substances, their functional property being not com- pletely destroyed under 70° C. They combine in a definite chemical way with the substances precipitated, but the reaction is prevented by acetic acid. They are believed to contain two essential atom groups : one, unstable and functional ; the other, a stable combining (hapto- phore) group. Precipitoids analogous to agglutinoids are known. There is another form of precipitin, called Coagulin, which is de- ^ Blood Immunity and Blood Jtielution&hip, Cambridge, 1904, riii'iaii'i'i'is's. 799 volojMid in lli- scrnms are, in some substano(!S, also spr-ei/icallv hicrnolvtic and sj)(!rn)otoxic. The agglutinins and the precipitins are more fiomple-x than the toxins and less so than the haTnolysiriH and haoteriolysins. Khrli(;h con(^eives of the individuals of this group of imrmme suhstanees UH ])ossesse(l of two atoin-eumpiexes, on(; of whi|)liyl;K!tic or uh a cnrative agent. The )>;i(ho!^'enic, or<;;niisnis other tli;in those (»f" diphtheria and tetanus n-tain their toxins within their cell snhstance, ;ind the innnnnc scrnnrs prodncr-d hy theii" introduction into livinjj:; animals arc; not antito.xic, hnt bac- teriolytic, and exert only temporary jjrotection and but siigiit curative a<^ti()n. The lack of success in the treatment of diseases caused by this class of bacteria is due probably to tlu; disparity in the amount of amijo- ceptor and complement in the immune serum. As has been pointed out, a bacteriolytic immune serum contains an enormous increa.se in the amount of specific amboceptor (sometimes 100,000 times as much), but no increase in complement. Inasnmch as the conjoint action of both is necessary for the destruction of the bacterial cells, it follows that, unless the patient can furnish the necessary amount of complement, the treatment must fail. To supply the needed additional complement is not an easy matter, even if normal serum be injected, on account of the multiplicity of complements ; for, according to Ehrlich and Mor- genroth, each kind of amboceptor re(piires a different specific comple- ment ; and hence they recommend the immunization of different species of animals with the same kind of bacteria and the utilization of a mixture of the several serums, thus bringing into action amboceptors and complements which, although differing according to the species in w'hich they are produced, are, nevertheless, specific against the same organism, and some of them, at least, may satisfy the needs of the human system. Not only does a deficiency of complement in itself present an insuperable obstacle to successful treatment, but the excess of amboceptor may also work injuriously by preventing the availal)le com}ilemeut from exercising its function, as has been shown by Xeisser and Wechsberg, who proved that it may unite directly with the com- plement, which has a greater affinity for free amboceptor than for that which has linked itself to the bacteria ; whereas, in the absence of an excess, the complement will unite with that which already has engaged the bacteria. Thus it happens that successful treatment depends U]X)n the very difficult problem of bringing together in the diseased system the proper amounts of ambocejitor and complement to cope with the specific bacteria. An excess of complement is not to be thought of, but a material excess, either of amboceptor on the one hand or of specific bacteria on the other, is fatal to success. 80-4 IXFECTION, SUSCEPTIBILITY, IMMUNITY. DIPHTHERIA. As has been stated, the disease in Avhieh the most brilliant results have been achieved in the application of an immune serum is Diphtheria, against which the agent may be employed either as a means of cui'e or as a prophylactic. Its introduction its a curative agent, in 1894, met at first with much adverse criticism, but its value was soon firmly established, and statistics of cases to the number of hundreds of thousands testify that the mortality has been reduced from about 40 per cent, to about 1 5 per cent, or lower. The statistics of the Boston City Hospital show that of 3067 cases treated during the period 1888- 1894, 43 per cent, resulted fatally ; while with antitoxic treatment the death-rate of 14,910 received during the period 1895—1904 was but 11.84 per cent. During the year ending December 31, 1904, the death-rate was 9.57 per cent., and if those cases which ended fatally within "twenty-four hours of admission are eliminated, this figure is reduced to 6.95 per cent. Preventive treatment has been practised exten- sively in schools, hospitals, and other institutions for children, but the immunity thus conferred is but transient. In a children's hospital in which an outbreak of diphtheria occurred, Lohr^ immunized 460 inmates and the outbreak was checked, no cases occurring within three weeks of the operation. Later, a few cases occurred, wdiich illustrated the temporary nature of the immunity. Of 99 patients with measles, treated because of the special danger of diphtherial supervention, not one was attacked. Similar outbreaks in children's institutions have repeatedly been checked, but since the protection conferred is so tran- sient, reappearance of cases is likely to occur, as in the instance cited ; and tS" guard against this, it is advisable to remove the inmates long enough to give the premises a thorough disinfection. According to Xetter,^ immunity begins after 24 hours and wears off within 3 or 4 weeks. JHe recommends that, when a case of the dis- ease occurs in a school, hospital, or other institution for children, the other inmates be treated. The treatment is advised also in measles and scarlet fever wards as a preventive of possible diphtherial complication. An instance is given in which the disease was a frequent complication in a measles ward, 2 to 4 cases occurring during each of 4 months, and 19 in the next succeeding 6 weeks, after which period each child was treated on entrance and no further cases occurred. The employment of the immunizing treatment as a routine practice is advocated by CailM' for young schoolchildren, for the purpose of preventing primary infec- tion and diphtherial complication of scarlet fever and measles. He recommends two treatments during the school year. Fig. 123, published by Park, shows the extraordinary influence of diphtheria antitoxin upon deaths from diphtheria in nineteen large cities of the world, from 1878 to 1905. It will be noted that the * .Jahrbuch fiir Kinderheilknnrle und physische Erziehung, September, 1896. ' Bulletin de I'Academie de Medecine, March 18, 1902. 3 Archives of Paediatrics, October, 1903. TF/rANUS HAY FhV/JJC sot •im 'MO •2'J) 2(10 180 ICO 110 120 100 80 60 40 20 fjb rr '80 '65 '90 95 00 r '05 ~~ i — — f \ 1 ♦ m ^ - 1 \ mi\ . / P 1 yi / p H 11 i A ^ 7 V A i « \ h ft) 1 \i h V 4 1 f vj ^ :i r 1 L A ^ 1 ^ ^ y I f i A \ '\ r \ k \ \ X A l~ i V ^ V ^ / b V !K 1 ^ t t u ^ § ■> d t^ \ ^ ^ / ^ ^ i; \ C ^ _,<^ jS 1 >^*^ i ^ ■=5 _ ..--t S e 5 LJ Deaths per 100,000 from croup and diphtheria in nineteen hirgc cities (l.S7S-190.'.|. (Park.) year 1894, which is shaded, was the year in which diphtheria antitoxin was first introduced. TETANUS. Like diphtheria, tetanus is due to extracellular toxins which are produced by the localized bacilli. They are conveyed in the blood stream to the cells of the central nervous system, for which, as has been shown, they have a selective affinity, and with which they form a very close union. Although it is possible to ])roduce an antitoxic serum which, in test-tube experiments, acts equally well with the diphtheria antitoxin in neutralizing the specific toxins, the antitoxic treatment of the disease luis failed signally in fulfilling expectations. This is because before the diagnosis am be established, the injury to the cells has been effected beyond the possibility of repair. The antitoxin is, however, valuable in aborting possible attack, and its injection liys become a routine practice in cases of gunshot wounds and similar accidents, especially after the annual observance of Independence Day. HAY FEVER. In hay fever we have a true intoxication, but the toxin is not of bacterial origin. The discovery of the cause of this exceedingly annoying condition is due to the investigations of Professor AVilliam 806 lyPSCTtON, SUSCEPTIBILITY, IMMUNITY. Dunbar, of Hamburg, who proved that the disease is due not to bacteria, but to the poison contained in the pollen grains of various grasses. In his first comnnmication ^ he showed the difference in the way susceptible and non-snseeptible persons react to the dissolved toxin ; 9 of the former subjected to its influence developed typical symptoms, and 20 of the latter were in no way affected. In a later paper- he showed that the autinnnal catarrh, which is peculiar to this continent, is caused by the pollen of goldenrod, ragweed and other weeds not indigenous to Europe. In the same way that diphtheria antitoxin is produced, Dunbar obtains a horse scrum which neutralizes the pollen toxin completely. This toxin is so powerful that one-forty- thousandth part of a milligram (corresponding to 2 or 3 pollen grains) is sufficient, when placed in the conjunctival sac of a susceptible per- son, to cause an attack lasting several hours, but it will yield readily to the antitoxin. Although the toxin of the grass pollens differs from those of the pollens of goldenrod, ragweed, etc., the grass-pollen anti- toxin neutralizes them all. Statistics collected by various writers abroad and in this country show most favorable results of treatment. Unlike diphtheria antitoxin, Dunbar's preparations (liquid and pow- dered forms) cannot be employed subcutaneously, but are applied locally. The serum, evaporated to dryness and converted to a fine powder with sugar of milk, is administered as a snuff in very small doses. It does not confer lasting immunity, and must be resorted to during the season at intervals of a day or two, or, if the outdoor air be unusually rich in pollen, at intervals of a few hours. For application to the eyes, the serum itself is preferred. It is said that in the majority of unsuccessful cases either the antitoxin is not used sufficiently often or is taken in excessive amounts, which aggravate the difficulty. In some cases the mucous membranes are in such swollen condition as not to permit absorption. DYSENTERY. Specific therapy has made a great deal of progress in this disease. Considerable confusion has arisen because of the varying types of bacillus found in different epidemics. The Shiga-Kruse variety has been found to be more virulent than the Flexner type and more effi- cient in the production of an anti-serum. A polyvalent serum pro- duced by inoculation with both types of bacilli has been suggested, and would seem to have the best outlook. The serum is both bactericidal and antitoxic. Good results cannot be expected unless the patient is injected with serum corresponding to the serum infecting organism. Bacteriological diagnosis is, therefore, very important, unless a poly- valent serum be available. As to the efficacy of the serum, reports from Japan, Austria, France, Russia, and England agree in according it marked power. Shiga ^ 1 Deutsche medicinische Wochenschrift, February 26, 1903. 2 Berliner klinische Wochenschrift, June 15, 22, and 29, 1903. 3 Osier, Modern Medicine. TY 1-1 10 1 1) FKVKR. 807 tr('<'it(!(l 21)8 cuH(!H, with ii dciitli-ratc of to 12 per ccni. Thr- Icrifrth of tli(! rtality was 22 to 2() per cent. Tlio.sc who reeovereii were Hi(;k I'orty (Jayn ; those who (lied eleven dayw. In UiiHHiu UoHenthul guvc Hcrum treat- ment to loT ersons, no less than 057 per thousand died in a single week (the third week of September, 1899). At Kirkee (India) the plague broke out in a small camp ; 671 persons were inoculated and 859 were left unprotected. Thirty-two cases occurred among the inoculated and 143 among the uninoculated. The mortality among the inoculatetl was 2.0v5, and among the uninoculated, 11.40, per cent. In another camp, » Ann. de I'Inst. Pasteur, Jan. 25, 1910. 2 Bulletin of the Johns Hopkins Hospital. November, 1903. 810 IXFECTTOX, SUSCEPTIBILITY, IMMUNITY. 324 persons were inoculated and 300 left unprotected. Fourteen cases occurred among the uninoculated and none among those protected. From further statistics which demonstrate the value of the treat- ment, the following may be quoted : In the Bombay Presidency, in one connnunity, among 3G5 persons who were inoculated there Avere 13 cases with 3 deaths, Avhile among 413 not inoculated, there were 48 cases with 36 deaths. In another community thei'c were 7 deaths among 5,184 inoculated, and 177 among 8,146 not inoculated. At Lanowli, among 323 who were inoculated, there were 14 cases with 7 deaths, and among 377 not inoculated, 78 cases Avith 58 deaths. Immunity appears to be prolonged by a second inoculation within ten days of the first, as is shown by the following figures : At ShaAvar, among 5,614 persons not inoculated, there Avere 957 cases with 756 deaths; among 5,712 Avho Avere inoculated but once, there Avere 69 cases Avith 31 deaths; but among 3,349 who were inoculated twice, there were only 9 cases with 5 deaths. Prior to the discovery of the Haifkine prophylactic, Yersin's anti- pest serum, Avhich is the only knoAvu remedy for the cure of the disease, was employed as an immunizing agent, but the duration of immunity Avas found rarely to exceed tAvo Aveeks, and hence the treatment must be repeated cA^ery fourteen days in order to insure protection. It is claimed by Calmette that the serum confers an immunity, certain and ciFectiA'c, almost immediately after the injection ; that the injection is not painful and is never harmful ; and that the serum, properly pre- pared, retains its poAver almost indefinitely. On the other hand, the disadvantages are the short duration of immunity, the great cost of production, the difficulty of obtaining a supply sufficient for the repeated treatment of entire populations, and the difficulty of inducing the natiA'^es to submit even once to the operation. It takes from seven months to a year to immunize a horse to the point that his serum acquires preventive and curative properties, and many of the horses die before the process of immunization is completed. According to Assistant Surgeon-General Greenleaf, protective inoculation by means of the Yersin serum is not practical for the following reasons : The enormous plant necessary for the production of the material ; the large Avorking force necessary for conducting the inoculations ; the opposition of the people to the treatment ; and the short duration of the benefit conferred. Cairns,^ Avho used the serum Avith some success in the treatment of cases at Glasgow, concludes that it is both antitoxic and bactericidal, and that it produces its best effects when the injection is made early and both subcutaneously and intravenously, the total initial dose rang- ing from 150 to 300 cc, according to the circumstances of the case. Both the Yersin serum and the Haffkine prophylactic are very un- popular with the natives of India. The Hindoos suspect that the materials are of animal origin, and the injection of such matters into the body constitutes an offence against their religion. 1 Therapeutische Monatshefte, May, 1904. ANTIHTni<:i"r<>(!()(!(ins SKIHIMS TUI'.EIiaULOSIS. 811 ANTISTREPTOCOCCUS SERUMS. Ant.iHtr(>{)t()(;()(!(;iis scrurus of" various kinds have l)<(rii (■rn[)l')V«''i in tlie treatment of Erysipelas, Puerperal Sepsis, Malignant Endocarditis and other Htniptoeocfiie infections and Scarlet Fever, hut thns far they have not fi^iven nvsnlts that intr, with cultures obtained from a numlxM' of subjects with difT'crcnt diseases, and also with cul- tures taken directly from a nnnilx-r of individuals with the same disease, as is the method followed by Moscr in the preparation of his jKjly- valent serum for scarlet fever. They have been prepared als^» by inoculating with organisms rendered unusually virulent by being passed througli a series of animals. How these various serums produce such results as have been observed Is a matter of some disagreement. It is believed by some that they are bactericidal, but this is denied by others, who believe that they act as stimuli to the j)hag()cytic cells. However they may act, the hoped- for results have not been attained, and innnunity to streptococcic invasion is evidently a very complex problem. The use of streptococcus vaccines in the prevention of scarlet fever has been practised very extensively in Russia, following lines laid down especially by Gabritschewsky and other Russians. They point out that the streptococcus is present in many scarlet fever throats ; that streptococcus vaccines cause scarlatiniform eruptions ; that complement deviation shows streptococcus amboceptors in scarlet fever blood ; that the mortality in scarlet fever has been markedly re- duced by the use of a serum jiroduced by inoculation of a scarlet fever streptococcus (Moser) ; and, finally, that by inoculation of streptococcus vaccines efficient prophylaxis against scarlet fever has been secured. This whole subject was reviewed by Smith,^ who concluded that from the published accounts it would seem that — 1. The streptococcus vaccines, used as advocated by Gabritschewsky, have some influence in controlling epidemics of scarlet fever. 2. Their use, with proper care, is attended by no harmful results. 3. They should be given a wider application in this country to prove or disprove the contentions of the Russian physicians. TUBERCULOSIS. Through ignorance of its dangers, sjiecitic therapy in tuberculosis received in its infancy a setback which it has taken years for it to recover from. Gradually, however, its laws and limitations have become better known and its great value is now recognized the Morld over. The favorable opinion refers now especially to active immunization produced by direct inoculation of the tubercle bacillus or its products. 1 Boston Med. and Surg. Jour., Feb. 24, 1910. 812 INFECTION, SUSCEPTIBILITY, IMMUNITY. It makes little difference apparently what variety of tuberculin is useil. More depends upon the method and skill of the physician. In- asmuch as, in animal experimentiition, inoculation with the living- bacillus produces the strongest immunity, we should, theoretically at least, aim to approach, as nearly as possible, these conditions in human treatment. This would lie secured approximately by a combination of living filtrate (Tuberculin B. F. of Denys) with bacillary emulsion (Tuberculin B. E. of Koch). Corresponding tuberculins of the bovine type are much used by Spengler, who claims that there is a mutual antagonism between the two varieties of bacilli and their pathological processes. Thus, he says, puiJmonary tuberculosis is the result of infection with the human types ofbacillus and must be treated with bovine tuberculin, whereas, tuber- culosis of bones, joints, and glands, being due to bovine bacilli, is best treated with human tuberculin. Be that as it may, bovine tuberculins may be tried in those cases which do not improve on the human varieties. The whole question of tuberculin treatment has been much clarified through the work of Denys and Trudeau, and has been well summed up by Ringer in the dicta that " time and tolerance " are the essential things, and that the word " haste " has no place in treatment with tuber- culins. Although in the past a careful selection of cases for tuberculin treatment has been deemed essential, the opinion seems to grow that practically any case can be inoculated if sufficient care be exercised. Allen has recommended in tuberculosis a vaccine made from tuber- culous sputum. Such a vaccine has a number of theoretical advan- tages. It is a mixed vaccine, contains primary and secondary invaders, the bacteria concerned are autogenous, and their fighting powers have not been diminished by artificial cultivation. Specific antisera have been used, especially in Europe. The best known are those of Marmorek and Maragliano. Opinions of these in their own countries have been, on the whole, favorable, but as tried in this country, at the Phipps Institute and at Saranac, the results Lave shown them to be of doubtful value. CEREBROSPINAL MENINGITIS. In no disease has serum treatment made more advance in recent years than in cerebrospinal meningitis. Most important in tiiis advance has been the work of Flexner ^ and his associates. Briefly, the serum is produced in horses by subcutaneous inoculation of dead cultures, living cultures, and autolysates of dead cultures. Many different strains of the meningococcus are used. After a year of immunization the serum of such a horse has been used intradurally after lumbar puncture in 130 cases, with 35 deaths, a mortality of 27 per cent. The dose is 20 to 30 cc, and may be repeated daily for four to five days if necessary. When cases are treated within the first twenty-four hours the results are most brilliant.' The serum seems to act by stimulating phagocytosis, which destroys cocci and renders harmless their endotoxins. ^ Flexner and Jobling, Jour. Exper. Med., 1908, No. 1. ^ Dunn, Boston Med. and Surg. J^ur., March 19, 1908. (lI'ULl'lUnosriNAI, MENINdlTlS. Mi;j Qiiiio Kiriiil.'ir n^siills liavc Itccii sffti in Ofrniaiiy. I'or iii.-laii<«-, L(!Vy/ iisinjf u scniin |>r<'|)ar, 1908. 2 Med. Record, Marcli 11, 1008. 3 Brit. I\red. .Jour., Juno 15," 1907. ■♦ The Lancet, July 27, 1907. 6 Miincli. med. Wocii., July 4, 1907. CHAPTER XVII. VACCINATION AND SMALLPOX. Prior to the discovery of vaccination by Jenner, toward the close of the eighteenth century, smallpox -vvas one of the principal scourges of the world. It killed, on an average, nearly half a million people in Europe alone, and about once in three years was more than ordi- narily severe. In England, Germany, France, Sweden, and other countries of Europe, the yearly mortality from smallpox was about two thousand per million inhabitants. More than half the cases of blindness throughout Europe were attributed to the disease, and about a third of the population showed in their faces evidences of having had it. It was well known that those who recovered enjoyed protection from recurrence of the disease, and consequently it had long been the prac- tice to produce immunity by causing the disease intentionally by inocu- lation when it prevailed in a modified form, favorable to recovery. For more than a thousand years, the Chinese and other Eastern peoples had produced the disease by blowing dried smallpox matter in pow- dered form into the nostrils. The discovery that the inoculation of material from a smallpox pustule was more certain and quick in its results led to the widespread practice of inoculation. This was begun in England in 1721, and toward the end of the century was em- ployed very extensively ; and even after the discovery of the beneficent results of vaccination, was practised to a certain extent, until, in 1840, it was prohibited by law. The first successful vaccination was performed by Benjamin Jesty, a Dorsetshire farmer, who inoculated his wife and two sons from the teats of cows aflflicted with cowpox. The inoculation was successful in all three cases, although the wife had a badly inflamed arm. Fif- teen years later, the two sons were inoculated with smallpox, but noth- ing resulted. It is said that Heim^ had noted as early as 1763 that the accidental inoculation of cowpox was followed by smallpox immunity. The practice of vaccination is, however, due to the w^ork of Jenner, who, on May 14, 1796, performed his first successful operation. After some very strong opposition, intelligent people began to adopt the practice, and the uneducated classes began to fall gradually into line. The practice was adopted in America, France, Germany, and, in fiict, the entire civilized world, and everywhere proved to be of the greatest benefit. In 1802, the English Parliament awarded Jenner ^ Nothnagel's Specielle Pathologie and Therapie, ly,, H. 2. 814 VAddrNATION AND SMAfJJ'OX. HIO 4,000 pounds .sicrlliiu;, ;in ho wjw tlie honorcid <^\U'.si. oC the .Icniicrian S(»ci<;ty. TIk! |)ra(!(i(^( was in(r(»du(;cd info this counlry l>y I>i". I>;et that you have lived. Future nations will know by history alone that the loathsome smallpox has existed, and by you has been extirpated." The beneficent results of the introduction of vaccination into this country are well shown by a comparison of the conditions ol)tainin<:^ in the early part of the eio:htcenth century and in the correspond iiif^ perif>d of the nineteenth in Boston. In 1721, Boston, with a population of about 11,000, had 5,989 cases of smallpox with 850 deaths. In 17:30, in a population of about 15,000, there were about 4,000 cases with 509 deaths ; but between 1811 and 1830, in a very much larger popu- lation, there were but 14 cases of the disease. In London, during the third quarter of the seventeenth century, the average annual mortality from smallpox per million was 4,000. A hundred years later, between 1770 and 1780, it was more than 5,000 ; in the first years of vaccination, it was more than 2,000 ; by the mid- dle of the nineteenth century it fell to about 500, and in the last decade of the century, to less than 75. In the whole of England, during the peroid of optional vaccination, the mortality-rate fell from about 2,000 to 417, and after the practice was made compulsory in 1850, it fell to 53. In August, 1898, the "conscientiously believes" clause was en- acted in deference to the anti-vaccinationists, and by December 31, 230,147 persons were exempted. The result of this modification of the law has recently been shown in extensive epidemics in London and elsewhere. In Sweden, where very accurate records have been kept since 1774, the average mortality per million of population, between 1774 and 1801, Avas 2,045. During the yciirs of optional vaccination, 1802—181(3, it fell to 480. In 1817, when vaccination was made obligatory, the rate began to fall still lower, and up to 1893 the average mortality was 155. During the last nine years of this period, under more stringent regulations, it was never more than 5, and in one year it was as low as 0.2. 816 VACCINATION AND SMALLPOX. In Prussia, during the period of optional vaccination, the mortality rate fell from more than 2,000 to about 300. During the Franco- Prussian War, there were among the million well-vaccinated German troops but 459 deaths, while in the smaller, imperfectly vaccinated French army there were no less than 23,400. Between 1874, when vac- cination was made obligatory, and 1896, there was but one death from smallpox in the whole German array. In 1899, the total deaths in 285 German cities and toM'ns, Avith a population of nearly 16,000,000, amounted to only 4. In the same year, in France, where vaccination is not universal, there were 600 deaths in 116 communities with a population of 8,500,000. In Austria, Hungary, and Belgium, where the practice is nf)t re- quired, the death-rates were, in 1886, respectively 81, 687, and 48 times that which obtained in Germany. In Spain, where, also, the practice is optional, the death-rate in six provinces, in 1889, was 12,050 per million against one of 4 per million in Germany. In Denmark, where vaccination was made obligatory in 1816, not a single case was known up to 1826. In Porto Rico, before the Sijanish War, the annual mortality from smallpox was about 600 ; but since the wholesale vaccination by the United States authorities, the disease has virtually disappeared. In all countries where vaccination has, at different periods, been optional and then required, a remarkable drop has occurred both in morbidity- and mortality-rates, and those countries in which, to-day, vaccination is not compulsory, suffer periodical visitations of the dis- ease and lose thousands of lives. In 1889, for instance, the death- rate from smallpox in Spain was nearly as great as obtained a century before in the principal countries of Europe, while in the same year, in Germany, the disease was practically non-existent. In France, in the tw^enty-five years from 1870 to 1895, more than 20,000 people died from smallpox in Paris alone, the epidemics of 1871 and 1872 being exceptionally severe and fatal. No epidemic has occurred in Germany since 1871, when the disease was brought in by French prisoners, although a few scattered cases have appeared occasionally. The Director of Health of the Philippines, in his annual report for the fiscal year 1907, states : ^ " During the year there has been unques- tionably less smallpox in the Philippines than has been the case for a great many years previous. In the provinces of Cavite, Batangas, Cebu, Bataan, La Union, Rizal, and La Laguna, where heretofore there have been more than 6000 deaths annually from this one cause alone, it is most satisfactory to report that since the completion of the vaccination in the aforesaid provinces, more than a year ago, not a single death from smallpox has been reported. So thoroughly are the Philippines saturated with the contagion of smallpox that probably 25 per cent, of the residents would soon succumb to this disease if it were not for the ability to protect the inhabitants against it by vaccination." 1 Quoted by Trask, American .Journal of Public Hygiene, Vol. XX., No. 1, Feb., 1910. VACCINATTON ANT) SMAIJ.I'OX. 817 III spiles <»(" ilic i'ciii;iil<;il)lf (fstiiiioiiy (■(Hicfniinp I In \;iliic dC v;ir- cination in Mi;il create. ;i. |M>|nil;ir ;iiil;iniiiii,-,iii to llic |»i:iclicc ;iii<| ff» f{\'i-c\ rcfwal of existing- laws. In Faitjjland, ;is li:is liccn noted, they havn Iwon partiiilly sncccssfnl in coinpcllina; the p.-issn^c of a l;i\v wliicli cxetnptH parents who have " consciciilions scniplcH" :ifrain.'«f having.' ihcir chil- dren vaceinaled. In progressive .Japan, where tlu; government lisw decided io coiii|»el \';iceiiialionbcfbr(! thea^c of" fen nionths, and revae- eination at I lie at;'c of .'-i.x and aL^'iin at twelve, the anti-vaeeiiiationlHt is unknown. Tlu! tbllowinji; fable shows flic smallpox niortalify of the several conntries named, in which vaccination is cither not comi)n].sorv or irn- porfectly pcrtbrmed, as compared with that ot'Ticrmany, which in each year is represented by 1 : Switzerland England . France . . Austria . . Belgium Holland. . Germany . 1898. 1894. 1895. 1896. 8 96 3 17 24 108 19 23 34 261 201 1,176 67 132 28 177 158 145 25 57 640 81 147 i 1 1 1 1897. 1898. 16 123 247 21 7 1 25 4 22 121 86 5 1 1889. 42 231 67 174 It cannot be claimed that vaccination confers absolute immunity against smallpox, but it is true that those who have been vaccinated and then acquire the disease have it in a much milder form and are more likely to recover than those who have not been vaccinated. In- vestigation of 11,036 cases of smallpox in England showe'>rt, because in P^ngland she had not been held for a definite j>erir)d at quar- antine. As an example of quarantine absurdity of a minor character, but indicative of what might be imposed in ease opportunity presented itself, may be cited an experience witli the municipal authorities at a. Southern port, who required thorough disinfection oi' a Ijarrel of car- bolic acid before it w^as allowed to be landed. Far more and almost incredibly absurd is the following instance : On November 3, 1893, the steamship Caho Machichaco, laden in part with dynauAte, blew up at her dock at Santauder, Spain, after having been on fire for some hours. The burning cargo was thrown about in all directions and started a general conflagration. It happened that the entire fire department was, at the time of the explosion, engaged in attempting to overcome the fire raging in the ship's hold, and in the ex]>losi(Hi was completely wrecked. Word was sent to Bilbao, and aid was urgently requested. Two steamships were sent with fire engines, firemen, surgeons, nurses, laborers, and others, and arrived in six hours. The provisional governor refused to jiermit the vessels to dock and discharge the much-needed apparatus and other aid, because quar- antine had not been observed, and he insisted that they should comply with the regulations, which would involve several days' detention out- side the harbor. It was several hours before a way was found to overcome the strict interpretation of the rules. The first action taken by any official organization in this country looking to the establishment of a uniform system of quarantine regu- lations was at a conference of boards of health at Philadelphia in 1857, called on account of the excitement caused by the breaking out of yellow fever at Bay Ridge in the previous year ; but in spite of this and other attempts, the various quarantines of the country were administered 822 QUARANTINE. with no uniformity until after the passage of the Act of FeT^ruary 15, 1893, entitled '^ An Act granting additional quarantine powers and imposing additional duties upon the INIarine Hospital Service." This act established a national system of quarantine, but in no way limited State and municipal authorities in their right to prescribe and enforce additional measures ; and, indeed, it is beyond the power of Congress to interfere with local authorities so long as the minimum requirements of the national law are complied with. Quarantine Law of 1893. Section 1 makes it unlawful for a vessel from a foreign port to enter any port of the United States, except in accordance with the provisions of the act and Avith such rules and regulations of State or nuinicipal health authorities made in pursuance of or consistent therewith, under penalty of not exceeding $5,000. Section 2 provides that a vessel at a foreign port, clearing for any port in the United States, shall obtain from the consular or medical officer of the United States at that place a bill of health in duplicate, in the form prescribed by the Secretary of the Treasury, setting forth its sanitary history and condition, and that it has complied with the rules and regulations prescribed for securing the best sanitary condi- tion of the vessel and its cargo, passengers, and crew. Penalty for clearing and sailing without such bill of health and entering any port of the United States, not exceeding $5,000. By an amendment approved August 18, 1894, it is provided that the provisions of this section shall not apply to vessels plying between foreign ports on or near the frontiers of the United States and ports of the United States adjacent thereto. But the Secretary of the Treasury is authorized, when, in his discretion, it is expedient for the preservation of the public health, to establish regulations governing such vessels. Section 3 directs the Supervising Surgeon-General of the U. S. Public Health and Marine-Hospital Service to cooperate with and aid State and municipal boards of health in the execution and enforcement of the rules and regulations of such boards and of those made by the vSecretary of the Treasury to prevent the introduction of contagious or infectious diseases into the United States and into one State, Territory, or the District of Columbia from another. It provides that all rules and regulations made by the Secretary of the Treasury shall operate uniformly and in no manner discriminate against port or place. Where no State or municipal quarantine regu- lations exist, and in the opinion of the Secretary' of the Treasury are necessary to prevent the introduction of such diseases, and M^here existing regulations are in his opinion insufficient, he shall make such additional rules and regulations as he may deem necessary, and they shall be enforced by the respective sanitary authorities ; failing which, the President shall execute and enforce the same and adopt such meas- ures as in his judgment are necessaiy, and may detail or appoint QlfAnANTlNJ'J LAW OF ixtifi. «2.''» officicrH for iliut i)ur|>()H(!. TIk; S(;c,r(!liiry of \\\i'. TrciiHiiry hIuiII iiiak'- siicJi rules ;iii:i,sH(Mij^<'rK, :iiiii I Ik; .SupcrviHluj; Sur^e<>H-(jr«;nr'raI U) |)(!r('(>nn ;ill llic diilics in respect to (|ii:iniiit iric ami (|ii:irantiiin n-^rn- liiiioiiK, !iii(l to ol)t:iiii iiiCoriiiMtion tlintii^li coiisiihir ofliccrs of tin; sani- tary eondilion oC Corci^in ports :ni<' ini|)orense to the nearest national or other quar- antine station where accommodations and appliances are provided for the necessary disinfection and treatment of vessel, passengers, and cargo. After treatment of such vessel and after certificatir a j)rinted copy thereof. As they stand at present, the regulations prescribe forms for bills of health, methods of inspection of passengers, crew, baggage, cargo, food and water supplies, and of the vessel itself; requirements as to cleanliness of vessels, and as to ventilation; m(!thods of disposal of bedding ; location and arrangement of the " sick bay " ; what may not be tidvcn on board at ports infected with certain diseases ; what must be di.siufected, and how ; Avhat persons may not be shipped, and periods of detention according to the nature of the disease to which they have been exposed; and general and particular rules to apply in certain cases. The regulations prescribe, also, requirements as to clean- liness and ventilation at sea ; isolation of the sick ; disinfection and disposal of the dead ; and give in detail the methods to be followed in disinfection of all parts of a ship, of various kinds of cargoes, and of personal eifects. The regulations to be observed at ports and on the frontiers of the United States provide for the establishment of quarantine stations at or convenient to the principal ports of the country, and prescril^e methods of inspection according to the circumstances of each case, as, for instance, for vessels from healthy or infected ports, and for vessels suspected of being infected with plague or yellow fever. Quaran- tinable diseases are named as follows : cholera and cholerine, yellow fever, smallpox, typhus, leprosy, and plague ; and rules are laid down for the government of vessels on which any of these diseases have occurred (hiring the voyage, and for the treatment and detention of passengers, crew, bagg-age, and cargo. Following the passage of the quarantine law of 1S93 and the promulgation of the regulations made in accordance therewith, at 826 QUARANTINE. many ports the quarantine service was surrendered voluntarily to the national government, and at others it was taken over by the same au- thority, because of non-compliance with the regulations. At others, the regulations have been ado])ted and efficiently enforced by the local authorities, but these and all others are inspected regularly by the Public Health and Marine-Hospital Service, to insure efficiency of administration aud correction of faults in methods and defects in ap])liauces. In 1900, there were in the United States no less than 120 quaran- tine and inspection stations, of which number, 81 were on the Atlantic coast, 17 on the Pacific coast, and 22 on the Gulf of Mexico. They vary, naturally, very widely in importance and equipment, the most important one beiug that of New York, the chief gate of entrance of immigrants aud of foreign commerce, and the least important being several with practically no arrivals of vessels from foreign ports. Only a small proportion are equipped with extensive disinfecting ap- pliances, aud but 8 are provided with quarters for the detention of persons held for observation. Interstate Quarantine. To prevent the introduction of contagious diseases from one State to another. Congress, on March 27, 1890, passed an Act providing that whenever the President is satisfied that cholera, yellow fever, small- pox, or plague exists in any part of the United States, and that there is danger of the spread thereof into other States, Territories, or the District of Columbia, he is authorized to cause the Secretary of the Treasury to promulgate such preventive rules and regulations as he may deem necessary, and to employ such inspectors and other persons as may be necessary to enforce them. These rules and regulations shall be prepared by the Supervising Surgeon-General of the Public Health and Marine-Hospital Service, under the direction of the Secretary of the Treasury, and any violation thereof entails a fine of not exceeding $500, or imprisonment for not more than two years, or both, in the discretion of the Court. In the case of any officer or other person employed to prevent the spread of said diseases, wilful violation of any of the quarantine laws of the United States or of any of the rules and regulations made and promul- gated as above, or of any lawful order of his superior officer or officers, the penalty is a fine not exceeding $300 or imprisonment for not exceeding one year, or both, in the discretion of the Court. Any common carrier or servant thereof who shall wilfully violate any of the same, shall be liable to a fine of not exceeding $500, or imprisonment for not exceeding two years, or both, in the discretion of the Court. State Quarantine. The national quarantine law and the rules and regulations made thereunder are, as has been said, intended only as minimum require- STATI-: qi J AHA NT INK. 827 monts, to vvlii<^li St'iic! or iniiiiici|):il iiiilliorily may rnako siidi ay a llmilid p( ri(jd, ili<' following-, ad(»pteoiiisiaiia, with releTeiic«; to vessels cn- ^'A\r,vx\ in the tropical iriiit trade; durinjr tin; Heason of 1899, may l>e eited. "All vessels eno-a^cd in (lie tropical I'niit trade between Central Ameriean, South Amcriean, and West Indian ports and New Orleanw will bo allowed to pass tiio MisslHsipjn Jiiver (inarantine Stjition with- out detention Ion<^er than is m^eessaiy for a thoron^di inspection by day by the (piarantine ol1i(u'rs, so lonjr as a proj)erly aeer<;dit<'d meil)lme iiutreasod indelinilcjy. In hospitals, on the otiier hand, whei'c indiscriminate ejrrcss and iiij^ress are under control and fa(;iliti(!S for the disiiilrcliven then, they should he kept under surveillance for a time equal to the period of incuhation. Jn times of epidemics of yellow fever in the South, house (piarantiuc of entire fuuilies has proved to be the cause of much hardship and anythiuu; hut an unqualified success. It causes great pojMdar dissatisfiu^tiou, l(>ads to (concealment of cases, and tends, tiierefore, to spread rather than restrict the disease. Treatment of the sick in isolatiou hospitals and removal of those who have been exposed to infection to camps of detention for five full days have Ix-cn found to give far better results. In some outbreaks of infectious diseases, it is necessary or advisal)le to conduct a house-to-h(nise inspection for the discovery and isolation of unreported cases. When such a course is undertaken, the visits should be repeated at intervals equal to the period of incubation. The making of regulations for municipal quarantine and inspection is subject to no general rule, each local authority lieing a law unto itself. In some cities, the rules governing notification, isolation, and disinfection are exceedingly thorough and strictly enforced ; in others, they are inadequate in varying degrees and enforced M-ith laxity. Camps of Detention. — Camps of detention are places set apart for the reception and observation of persons who have been cx]ie strictly prevented. At the expiration of the proper ]>eriod. in each case the clothing and other personal effects should be thoroughly dis- infected before dischariie. CHAPTER XIX. DISPOSAL OF THE DEAD. The public health reqiures that the bodies of the dead shall be disposed of" in such a way as not to be a menace to the living, and as soon as possible, with due consideration of the feelings of those bereaved. In the case of those dead of infections diseases, disposal should not be delayed by sentimental considerations, but should be accomplished with as little delay as possible, on account of the risk to which the living may be subjected by the retention of the body in the home. Concerning methods of disposal, consideration may be limited to the two in use by most civilized peoples and by most others as well ; namely, earth-burial and cremation. Earth-burial. — Interment of the dead has ever been the principal mode of disposal among Christians, Jews, and Mussulmans. Within comparatively recent years, the results of overcrowding of ancient churchyards and cemeteries, and the necessity of dedicating great areas of valuable land to be held in perpetuity for the accommodation of the dead, have brought about an economic sentiment against the practice, and to it has been added a feeling of danger to the public health from the decomposing tissues, particularly of those who have died of infectious diseases. Buried in soil of suitable character, a body gives off for a number of months — six to nine may be regarded as reasonable limits — foul gases of decomposition which are not evolved in the later stages. The rate of decomposition is influenced not alone by the nature of the soil, its pore volume, and its degree of moisture, but also by the character of the coffin, the depth of interment, and the processes to which the body has been subjected before burial. After some years, the period varying within very wide limits according to circumstances, decomposition is complete and but little remains besides bones, more or less crumbly in character. It is charged against earth-burial, that the places used for the pur- pose are offensive ; that the air becomes poisoned ; that the soil be- comes laden with disease germs of all descriptions, which are pre- served indefinitely, and that water supplies are converted to dilute poisons of great potency ; that is to say, cemeteries predispose to and act as direct causes of disease. As proof, numerous cases which will not bear close scrutiny are cited, but the whole mass of what is m J'JA 11 Til- li (nil A L. H.'J 1 r('|i;;if(l('(l ;i,h ((vidciicc of llic coinicction of ffiiK't^-rifH with tlio outhn-jik of (IIh(:;is(! Iiiis hill little ir:il wi'ImIiI ;iii<| is iiiic.oiiviriciiif^. It lias boon Siiid, lor cMiiiipIc, tli;i(. typliiis :iner examination. In some States, legal provision has been made, forbid- 53 834 DISPOSAL OF Tin-: DEAD. diner ernbalining in case of dcatli by violence, until the body has been *' viewed" by the proper authority, and providing ibr proper certifica- tion before incineration. History of Modern Cremation. — According to Ja])anese authoi-i- ties, crematiou, as at present practised among ci\ilized nations, had its origin in their country many years ago. Until 1871, however, no special crematories were installed, the body in its coffin being placed on stones surroui'ided by wood or other inflanimable material. In that year, crematories were erected ; and since then, the practice of incineration has increased to such an extent that, in 1897, in Tokio, of 34,000 per- sons who died, 15,000, or 44 per cent., were cremated. In 1898, the percentage was about the same. In this country, the first movement in favor of cremation occurred in New York, in 1873, but the first crematory was not erected until Pig. 124. 187G-'83 'Si '85 '8C '4i7 '88 '89 '90 '91 ■'92 '93 '91 '95 '90 '97 '98 YEAR Curve showing number of crematiDns in the United States. (After Abbott.) 187G. This was built at Washington, Pa., by Dr. J. T. LeMoyne, for the disposal of his own body, and was the only one in the country until 1884, when another was established at Lancaster, Pa. During this interval of eight years, the use of his crematory was allowed by Dr. LeMoyne for others, and 25 incinerations were performed. Be- tween 1884 and 1900, the number of crematories increased to 26, which growth indicates a steady increase in public sentiment in favor of the process. The number of cremations performed in the United States from 1884 to 1899 is shown in Figure 124 from the monograph lIlsrollY or MODKIIJS CnJJMATION. 835 sr: 2: iliiiimiS^ii^iiii^ii^^- 10 . . jr^ ►£ . t-'COCO*' to g- • ^8- ""*■ • fe' ■ £2t'^' OlfcJ 1- CO — o 00 tc o-'Oiooci-i-''y- ■~J 1 !-• OC (C •— 03 » — CO 3; • Cs CO I-' -J *■ m ^ J- o c. CI — w' c. J >- ae - ■-' 5 *». O — SMC^'OtJtO'^g'J^t'^''^'^'"^^'^'''^''^ 2; ciS cotO'-"-^c^oo^^ oh_o-j>£^^^c^»'&-^>— C)£ ^1 I CO to Q-i -^ tc o o tc — ic 3C ^ -; K- ^1 £ 3 I ia>t2 agS" StaslsxgSi^ggScc £g: S I ^ - n: X =; i^" ,--! - « tS I S&50 SoWCJ S O .6- C-^ - ^ --' O X - '^±:l£^ ^jH^co*.. .CO. .o>c>. ot/tigc to -vi CO 5 E o5 —>» tcib- Ci*-~ic^ iJ ■ CO i" 'ocoS-iot3t^^ octci-'iccnoic ' n o o 50 w >• H o GO o GO H o c! CD l-H ^ csucjco. t::52??§gS^§5 ggi^t^ggl^ i M. 83G DISPOSAL OF THE DEAD. I— ( O H ^oco-ro50-:ro so i-< Ol 00 1 g|§^S°'§S82S22 i -1^ sssss'°|3ss:s'°s g S rH 5; «5 |S^^SS|2SS?53«' CO 1 §SSSS''|S§IS°'^'- i s §g§S§S'^S'*2 • • • • rH 1 CO .-1 ^ s MtOOOOl^T-1 s;^'^^" lO 5 s —J 3 O 00 C^ '^ CO CO §i8S?? i C-l 00 -^ _, ^J J^ 1-1 ^ ^ ^ <» en 1 H CO ^i o I> lO 1-1 rH ' ' o OO r^ cj o C3 i CO O .H *"* in _ _ i §o"^ ■^ s c^ -^ T— 1 CO O CO *"* ■1-1 -^ rfs o 1-1 o ' ^ § en en CO 3 s :::;::::::: : 1 CO «5 OO 00 ^ s :;:::::;:;: : l- CO to s s ::■■.::;:: : ■-( i CO CO r-H a.aoo. 'c'-ws .;_,.2'i> 1 1 5 .> = S c -s .S 2 -S g ^ "cS o H IllSTOliV OF MOIHCliN CILKMATIOS. 8.'i7 l)y Dr. S.'itriiicl VV. AhhoK,' roritriWiitcd hy flu; (.'oriirnoriwfaltli of M!iss;i(!liiiH(!llH l.o tlu! lliiilf'd St.'ilcs Social Iv-onoiriy Kxliibit at tin; Paris Pjxpositioii. Diiriiifj^ tliis period 'S88r> cniruatioiis ofir.iirn^J. TIk; tabic oil |).'if^o "i^Wr) shows tin- fiirtlicr progrcsH of" tlie luovcriicnt ill tli(( Uiiitwl States. Tlic ^rowlli oC the inovctnoiit in Gn^at IJrifain lip to 11)10 is sliowri oil paj^c H.'iO." A inovctncnt toward (TCMiialioii Ix'gaii in Italy in 1857 ; liut nothing was ac(!oinplisli(!d until 1807, (line years after legal sanction waH rth- tained. In 1JK)1 tluTc; wen- in Ilaly 22 cr«imatorie.s in ofK^ration. Germany liad, in 11)01, 7 estaMislimcnts, the first of whi(;li was in- stalled at Dresden in 1871; (Jreal liritain had 7, the first of whir-h was eslahlished in London in 1880; I^'i-ance had 2, Switzerland had 3, Sweden had 2, and Denmark had 1. According to Sir Henry Thomjison,' there were in tin; United States during 1901, no less than 2,(505 incinerations; in Germany, 693 ; in England, 445 ; in Paris, 297 ; in Italy, at 12 of the 22 institutions, 243; in Switzerland, at 2 of tin; .'> institutions, 144. In the destruction of the body, the apparatus is so constructed that, while reduction to ashes is (iomplete within three hours, no offensive fumes are given off. Commonly, the l)ody, incloswl in a simple wooden cotlin, is placed in the retort, which is then intensely heated by an oil ilanie, with which air under pressure is mixed ))y a blower. 1 The Past and Present Condition of Public Hygiene and State Medicine in the United States, Boston, 1900. = British Medical Journal, Mar. 5, 1910, p. 579. 3 Tlie Lancet, July 5, 190'J. INDEX. AllDOMlNAt. I);ui(1h, 01^2 Ahywsiiii.'i.n vvtIIh, I5S7 Acctylctid Ki'M '" illiiiiiiriM.1 ion, ')()() Acid, l)<)ri(^ 'i.lS cITccI, of, on (iii^cslion, 'JtlO in milk, IIS delect ion of, HiO (carbolic, TjSI) hypochlorouH, as disinfcclanl, T)?? oxalic, 24 standard solution, 304 phonic, as disinfectant, 586 salicylic, 2()l detection of, in beer, 2:5:} in wines, 240 in milk, 120 detection of, KiO Acids, mineral, as disinfectants, 585 organic, 24 Actinomycosis, milk afTected by, 128 Age in vital stalistics, 751 statement of, 744 Agglutinins in serum, 796 Air, 269 disinfection of, 612 examination of, 297 bacteriological, 314 filtration of, 493 humidity of, relative determination of, 299 infection carried by, 290 pollution of, through lighting, 501 saturation of, 279 in soil, 329 vitiated, effects of, 286 occupations exposing to, 723 in water, 371 water capacity of, 299 Albuminoid ammonia in water, 375 detection of, 445 Albuminoids, 23 Albumins, 20 Alcohol as disinfectant, 591 in beer, percentage of, 223 in ration, 643 in tropical hygiene, 685 in wines, 236 Alcoholic beverages, distilled, 241 fermented, 217 Aldehyde catalase, 105 Alga\ destruction of, in water, 412 Alkaline potassium permanganate, 445 soils, 3 IS Alkalinity indicator, 304 Alkaloid.s in b(;vc;rag(«, 210 Allspic*!, 251 Almonds, 194 Aluminum dilorido iw diHinfcctant, 5S1 kitclicnwarc, 2(>H in soil, :>1.S American wells, 3S7 Ammonia in air, 275 permanent staiidard.s of, 449 in soil, 319 in water, 373 determination of, 445 Ammonia-fr(M! water, 446 Ammonium chloride, standard solutions, 445 Amykose, 104 Aniiin orange, 160 Ankylostomum duodenalo in water, 442 Annatto, 158 Anthrax, milk affected by, 128 soil relation to, 349 Antistreptococcus serum, 811 Antitoxins, 783 Aiiplcs, 201 Apricots, 202 _ Aqueous vapor in air, 276 . determination of, 298 Arachnids, relation of, to diseases, 696 Argand burners, 498 Argon in air, 272 Arrowroot, 193 Artesian wells, 3S9 Artichokes, 199 Ascaris lumbricoides in water, 441 Aspirating cowls, 480 Aspiration in ventilation, 479 Attitudes in hygiene, 738 Aurate of sodium as disinfectant, 585 B. Babcock asbestos test, 151 centrifugal test, 150 Bacillol as disinfectant, 590 Bacon, smoked, 30 Bacteria in air, 2SS in milk, 105 conditions affecting, 110 nvmiber of, 107 source of, 110 of soil, 340 in water, 379 Bacterial action in purification of water, 397 S39 840 INDEX. Bacterial diseases in animals, 45 poisoning of foods, Go toxins, 783 Bacteriological exaniiualion of air, 314 of soil, 302 of water, 462 Bactcriolj'sis, 788 Baler's test, 104 Baker's chemicals, 246 Baking powders, 251 Bananas, 204 Bands, abdominal, 632 Barium hydrate solution, 303 Barley, 180 malt, substitutes for, in beer, 220 Barracks, 652 Bathing, 752 Bath-tubs, 532 Beans, 191 Bed-bugs, relation of, to diseases, 695 Bed linen, disinfection of, 611 Beef, composition of, 29 good, characteristics of, 27 poisoning by, 84 poisonous, characteristics of, 71 Beer, 217 acidity of, 233 adulteration of, 222 alcohol in, determination of, 223 barley malt in, substitutes for, 220 composition of, 222 ash, 234 extract of, determination of, 232 hops in, substitutes for, 221 manufacture of, 219 methyl alcohol in, determination of, 229 physical properties of, 222 preservatives in, 233 specific gravity of, 224, 232 Beets, 199 Bernstein's test, 163 Berries, 204 Beverages, 210 alcoholic, distilled, 241 fermented, 217 Bicarbonate of sodium, 264 Bichloride of mercury as disinfectant, 582 Bilharzia haematobia in water, 442 Biological agencies afTecting soils, 328 Birth-rates, 749 Biscuits, 183 Bisulphate of sodium in purification of water, 403 Blackberries, 204 Blackboards, school, 473 Blankets, waterproof, 632 Bleaching powder as disinfectant, 575 Body louse, relation of, to disease, 696 measurements of, 621 Boiling meat, 26 in purification of water, 404 water as disinfectant, 568 Books, disinfection of, 616 Boots, 630 Borax. See Boric acid. Bored wells, 388 Boric acid, 258 elToct of, on digestion, 260 in milk, 118 detection of, 160 Bovine tuberculosis, human tuberculosis and, 50 Brand's test, 233 Brandy, 242 Bread, 180 pulled, 183 Broiling meat, 26 Bromine as disinfectant, 577 in i^urification of water, 401 Bubonic plague, air as carrier of, 295 immunization in, 809 soil relation to, 846 Buckwheat, 189 Burial of dead, 830 Butter, 164 Butyric ferments, 107 Butyro-refractometer, 171 Caffeine, 210 Calcium, 24 chloride, standard solution of, 453 oxide as disinfectant, 580 Cameron tank, 554 Camps of detention, 829 military, 649 Cane sugar, 205 Canned fish, 38 meats, 30 Canning, preservation of food by, 254 Canteen, army, 644 Capillarity of soil, determination of, 359 Caramel, 159 Carbohydrates, 22 Carbolic acid, 586 Carbon dioxide in air, 272 determination of, 303 in soil-air, determination of, 360 in water, 372 monoxide in air, 280 determination of, 311 Carbonate of sodium, 120 Carbonates in soil, 218 Carbonic acid. See Carbon dioxide. Care of person, 762 Carrots, 199 Cassia, 251 Catalase, 105 Cayenne pepper, 251 Celery, typhoid fever transmitted by, 64 Cellulose, 23 Cemeteries, 832 Census, 743 Cereals, 178 Chafing, care of and prevention of, 639 Chairs, school, 472 Cheerfulness, 627 Cheese, 173 Chemical agencies affecting soils, 328 agents as disinfectants, 571 iM)/':x. 841 Ohorriion,! [)r(!f;ii)il,;i,(,i()ri of HowaKo, fil'i l)iii'ili('.,'i,li()n <>( wii.lcr, .'{9X Cluitnicids, hiikcrH', 2U'> pn^HcrviiXioti of food liy, 'jriCi of inilk hy, IIS Ch(!rri((H, 202 Ch(iHt, r:\.])nc\ly , (^x.'Uiiinjilioii of, (i2() m(^iiHiir(;iii(M)l,H, <'»2l (;ii(i.slrMit,H, l!)4 ('liicory, 214 Cliildrrti, (lc;i,l,li-r;iJcH of, 7r)(l (MiipioyifK^il- of, 740 (!lil(>ri(l(^ of limn iiH iS ill wa,ti'r, ;i77 (leUinirmal ion of, 452 (lliocolal.o, 217 CHiolcra, air as carrier of, 296 food as l)(>arcr of, 58 iminunizalion in, SOS infantiiin, mill< as licaivr of, 144 milk as bearer of, 1 .'i7 8oil relation to, .'i4() wai.er reflation to, 4l!() Chroinates, 122 deteetion of, in milk, 162 Cider, 240 vine{i;ar, 247 Cinnamon, 251 Circulation in active exercise, 765 Clays, 316 Cleanliness, personal, 627 Closets, 520 disinfec^tion of, 616 Clothing, 770 adulteration of, 776 disinfection of, 611, 615 selection of, 778 of soldier, 628 in tropics, 687 under, 631 Clouds, 279 Cloves, 250 Coagulated proteins, 21 Coal-gas in illumination, 499 Coal-tar colors in wine, detection of, 239 Cocoa, 215 Cocoanuts, 194 Coffee, 213 Cold as disinfectant, 569 preservation of food bv, 254 of milk by, 114 Color in clothinc;, 629, 770 Colostrum, 102 " Complements in serum, 793 Condensed milk, 124 Condiments, 246 Confectionery, 209 Constitution of population, 746 Constrained attitudes, occupations in- volving, 738 Contact filtration of sewage, 550 Contusion, 7HI ( loritfrritrricrif , 627 (yorivectioii in vritilatinK, 4H0 Cr)okiiig rnc'ilH, 26 Cop|)<;r, forxl r^oiitHminjilerJ by, 2<>4 Hulphiilc iiH (JiHitifcctarit, 5H2 Cordon, Hanitury, H2H (;orri, 1H7 ('orncrd b«'cf, 30 Corrosiv*^ subliinate ;lm (liHinf'Ttunt, 5S2 Cotton, 774 rlotliiiig, 62S Cotlr)ri-H<'r-(| oil, 19t> Cowls for ventilation, 479 ('rackcTH, 183 (^raribf-rries, 204 ('r.'iwfisli, tyjilioid fever tranHmittwl by, 64 Cream, 124 gclalin ill, detection of, 16.''» sucrat,e of lime in, detection of, 161 Cremation, 832 apparatus for, 837 history of, 833 statistics of, 834 Creolin a,s disinfectant, 589 Cresol jin^parations a.s disinfectants, 587 Cucumbers, 201 Currants, 204 Cyanide of mercury a.s disinfectant, 584 Cysticercus in meat, 39 D. Dampness, occupations exposing to, 737 Dead, disposal of, 830 Death, causes of, 758 Death-rates, 751, 754, 756 weekly, 754 Dcceco closet, 527 Dengue, relations of mosquitos to, 714 Densitj^ of population, 753 Desks, school, 472 Detention camps, 829 Dew-point, 301 Dextrose, 23, 206 Diarrhoea, epidemic, soil relation to, 354 infantile, air as carrier of, 296 Diarrhoeal diseases in army, 669 Diastase, 104 Diet, regulation of, 764 in tropics, 684 Diffusion in ventilation, 476 Digestibility, comparative, of meats, 28 Digestion, effect of exercise on, 767 Dioxide of sulphur as disinfectant, 577 Diphtheria, air as carrier of, 295 immunization in, 804 milk as bearer of. 136 soil relation to, 347 Discharges, disinfection of, 611 Disease, air as carrier of, 290 butter as carrier of, 167 dissemination of, 609 occupations exposing to, 735 exciting causes of, 780 84-2 INDEX. Disease, food as bearer of. 44 insect relation to, 690 soil dampness and, 342 relations to, 342 susceptibility to, 781 water relations to, 420 Diseases of sailors, 677 of soldiers, 665 tropical, 6S8 Disinfectants, 560, 571 alcohol as, 791 carbolic acid as, 586 chemical, 571 cresol preparations as, 587 essential oil as, 593 fonnaldeh3'tle as, 598 iodine as, 577 metallic salts as, 581 mineral acids as, 585 non-metal, 572 physical, 560 soap as, 594 Disinfection, 609 by formaldehj'de, 599 special, 610 Disposal of dead, 830 Dissemination of infectious material, 609 Distillation in purification of water, 404 Distilled alcoholic beverages, 241 Distilling apparatus, 446 Distomatosis, 43 Domestic filters, 404 Dracunculus medinensis in water, 441 Drainage areas, 391 Drains, 504 Dress coats, 629 Driven wells, 387 Drying, preservation of food by, 254 Duration of life, 759 Dust in air, 278, 288 determination of, 313 poisonous, 729 occupations exposing to, 740 Dwellings, 470 Dyes, poisonous, 777 Dysentery in army, 668 immunization in, 806 Earth-btjrial, 830 Eating utensils, disinfection of, 611 Egg-plant, 201 Eggs, 91 Ehrlich's theory, 783 Electric lighting, 502 Emergency ration, 642 Enamelled kitchenware, 268 Endocarditis, immunization in, 811 Enteritis, specific, milk affected by, 128 Epidemic poisoning by food, signs of, 68 Erysipelas, air as carrier of, 295 immunization in, 811 Essential oils as disinfectants, 593 Evaporation from oil, 335 Examination of recruit, 625 Exercise, 765 amount required, 768 kinds of, 769 over-, of parts, 739 of soldier, 63)5 Expectation of life, 760 Fabrics, chemical analysis of, 777 microscopical examination of, 777 Fieces, disinfection of, 610 Farinaceous preparations, 193 seeds, 178 Fats, 22 in butter, determination of, 169 in milk, 97 determination of, 148 vegetable, 195 Fatty seeds, 193 Feces, disinfection of, 610 Feet, care of, 638 Fehling's test, 152 Felt in clothing, 776 Fermented alcoholic beverages, 217 Ferments, butyric, 107 lactic, 106 of milk, 103 peptonizing, 107 salol-splitting, 105 Ferric chloride as disinfectant, 581 test, 161 sulphate as disinfectant, 681 Ferrous sulphate as disinfectant, 581 Field ration, 641 Figs, 204 Filaria sanguinis hominis in water, 442 Filarial disease, relation of mosquitos to, 712 Filipino ration, 649 Filter galleries, 393 Filters, 404, 412 Filtration of air, 493 contact, 550 of public water supplies, 406 in purification of water, 404 in sewage disposal, 548 Fish, 35 composition of, 38 disease transmitted by, 44 parasitic, transmitted by, 38 poisoning, 64 preserved, 38 Fitz's test, 310 Flame, luminosity of, 497 Fleas, relation of, to disease, 694 Flies, relation of, to disease, 691 Flour, adulteration of, 184 bleaching of, 185 wheat, 179 preparations of, 180 Fluke in animals, 43 life history of, 43 Fluoride of sodium, 264 Fluorides, detection of, in beer, 233 Fog, 279 INDEX. 843 FoK, v\U-(:\H of, 2!)7 K()()(Ih, juiioiiiit. ii(!(;(!HHiiry, IS .'iriiiri;i,l, 24 oiiloriinclric! v.'iliu- of, IN (•(niipo.sitioii of, I'.) colli, .■iiniiiii,!. ion of, l>,\' iiicI.'lIs, 'Zi'A luil-rilivi' v.'iliK^ of, 17 |)r('|);uii,f ion of, (111 l)r('M('rval ion of, 25.'$ (ilicinic!!,! 2r)() rations of, for .sol(li<'r, G.''.!) vcnc(.ii,i)!c, 177 F()ot-a.n(l-tiioul li iliflcasc, niilk affcftfcd l)y, 127 I'\)nnal(lchyi':x. 845 M,'ui(i;;uH!,s(', in soil, I'. IS Miinihiii^!;, ('):{:'. M:i,rii)(! \\y\i^\v.w, ()7I MiirlH, 'Ml M,•u•^i!W-^l,l.(^M, 7'1.S Mmitow, Ix^cf, ;>() MjimMUh, mills ;iJTcc(.(;(l hy, I2S Mill rl.n'SH(^H, (lisiiirccl ion of, 015 Mc:ui ;i,ri,(T-lilr l-iiric, 7<)() (liirjilion of life, Tf)'.) M(',iisl(« in urrny, (iCiU Mousurninrnis of hoily, ('i21 M(siil)ilil.y of, compjiralivc, 25 disease 1,ranHniiU,e(l by, 44 extracts, 83 good, charactorisl i(\s of, 27 inspection of, S*.) tubonMilosia and, 48 poisoning, 04 from diseases of animals, 40 powder, 33 texture of, 26 Mechanical filters, 412 ventilation, 485 Medicated soaps as disinfectants, 590 Melons, 203 Meningitis, epidemic, air as carrier of, 295 immunization in, 812 Mercuric chloride as disinfectant, 582 cyanide as disinfectant, 584 Metakaline as disinfectant, 598 Metals, foods contaminated by, 264 Metaproteins, 21 Metchnikoff's theory, 801 Methyl alcohol, deterniination of, in beer, 229 Micro-organisms in air, 278, 283, 288 in soil, 319 Military hygiene, 617 Milk, 95 adulteration of, 122 analysis of, 140 bacteria in, 105 coiiditions affecting, 110 source of, 110 bactericidal properties of, 103 biological properties of, 103 condensed, 124 constituents of, 97 cooked, detection of, 162 detection of added water in, 154 of coloring matter in, 158 of preservatives in. 160 determination of ash in, 153 of constituents of, 151 of fats in, 148 of specific gravity of, 147 diseases transmitted by, 125 ferments of, 103 Milk from diHf;iHed rrowH, 127 inffrctiotiH, acute, IranMinif ti'dby, 136 I)l)yHi(;al prri|)fTtifH of, 99 poiHorK)iiH, 125 lircHcrviilion of, 1 14 clicfni(;al, I IS produclH, 10! rc'iction of, '.)'.) slrrilizalion of, 1 14 Mineral acids .-us (\'\»\\\U'V.\m\\h, 5K5 tiiatters, diw^iiHf; and, 421 in watfT, 37S Mist,, 279 Moisture, detfrmination of, by w«-i((hinp;, 298 needed in healing, 491 of soil, df^tenninalion of, 359 Mohisses, 207 vinegar, 248 Mos((uitoeH, relation of, to diseauo, 696 Moulds in air, 288 Muck soil, 318 Mulberries, 204 Municipal ciuarantine, 828 Mushrooms, 205 Mussels, poisoning by, 72 Mustard, 2.50 Mutton, composition of, 31 good, characteristics of, 27 N. Naphthol, a-, test, 103 Nai)hthylamine solution, 4.50 Naval hygiene, 671 Nervous system, exerci.se and, eflfect of, 766 Nesslerizing tubes, 447 Ncssler's reagent, 445 Nickel, food contamination by, 267 kitchenware, 268 Nitrates in .soil, 319 in water, 375 determination of, 450, 451 Nitrifying organisms in purification of water, 409 Nitrite, permanent standards, 451 Nitrogen in air, 271 compounds in air, 275 in soil, 318 Norton's tube wells, 387 Nucleoproteins, 21 Nutmeg, 251 Nuts, 193 0. Oatmeal, 187 Oats, 186 Occupations, classification of, 721 hygiene of, 716 of women and children, 740 Oil, cotton-seed, 196 essential, as disinfectant, 593 olive, 195 Olein, 22 84G ISDEX. Oleomargarine, 166 Olive oil, U. S. Standard for, 195 Open closets, 525 fires, 4S7 Opsonins in serum, 802 Oranges, 202 Organic matters in air, 286 in soil, detection of, 360 in water, 372 pollutions of water, relation of, to disease, 423 Overcrowding, 2SG Overexercise of parts, 739 Oxalic acid, 24 standard solution of, 304, 454 Oxidation in purification of water, 396 in soil, 319 Oxytlascs, 105 Oxygen in air, 269 as disinfectant, 572 required for decomposition of organic matters in water, determination of, 454 Oxvuris vermicularis in water, 441 Oyster plant, 199 Oysters, infection transmitted by, 58 poisoning by, 75 Ozone in air, 274 determination of, 312 in purification of water, 402 P. Pail system of sewage disposal, 541 Palmitin, 22 Pan closet, 523 Paper coil extraction test, 148 Paralysol as disinfectant, 598 Parasitic disease, fish and, 38 meat and, 38 water and, 441 Parsnips, 199 Pasteurization of milk, 114 Peaches, 202 Peanuts, 194 Pears, 202 Peas, 191 Peat soil, 317 Pectin, 23 Pectose, 23 Pepper, 250 Cayenne, 251 Pepsin, 104 Peptides, 22 Peptones, 22 Peptonizing ferments, 107 Perflation in ventilation, 479 Permanganate of potassium as disinfect- ant, 582 Permeability of soils, 320 conditions affecting, 323 determination of, 356 Peroxide of hydrogen, 120, 263 in air, 275 as disinfectant, 574 Peroxydase, 105 Perry, 241 Person, care of, 762 in tropics, 688 Personal cleanliness, 627 of sailors, 680 hygiene, 762 Phaseomannite, 23 Phenic acid as disinfectant, 586 Phenol as (Hsinfcctant, 586 Phenoldisulj^honic acid solution, 451 PlK'nolphthulein solution, 304 Phloroglucin test, 161 Phosphates, 24 in soil, 318 Phosphoproteins, 21 Pike, poisoning bv, 75 Pimento, 251 Pin worms in water, 441 Plague, air as carrier of, 295 immunization in, 809 soil relation to, 346 Plumbing, 502 testing of, 537 Plums, 202 Plunger closets, 524 Pneumonia, air as carrier of, 295 Poisoning by beef, 84 by carbon monoxide, 281 by cheese, 177 by fish, 64 by herrings, 73 by horse meat, 86 by kid meat, 89 by meat, 64 diagnosis of, 69 postmortem appearance in, 69 symptoms of, 68 by milk, 126 by mussels, 72 by oysters, 75 by pike, 75 by pork, 78 by potatoes, 198 by salmon, 74 by sausages, 87 by veal, 76 Poisonous bacterial products in foods, 65 beef, 71 cheese, 176 dusts, 729 occupations exposing to, 740 dyes, 777 fumes, occupations exposing to, 723, 741 gases, occupations exposing to, 723, 741 milk, 125 sausage, 71 species, 64 veal, 70 Polariscopic tests, 153 Police, sanitary, 660 Pollution of air by lighting, 501 of soil, 338 of water, disease and, 423 of wells, 391 INDEX. 817 P()|)iil;il.i()ii, cHl-irii.'ilioM of, 745 Porc-voluirH; of Hoilw, :'. I'.» (l(!t.(U'initi;i,l-iori ol', '.'u)h Pork, coinpoHit.ion of, ;>() (rood (tluiDLct.criHlicH of, 27 jjoiHoriin^!; by, 7.S NaJl,, :i() PohI.h, inilif.'U'v, M\) PoUiHHiiiiii clifoni;i,l,(^ Holul.ion, 4r)2 iiiLraLc .4(.!Ui(l;inl Holulion, 451 pcrmaiiKHiiaUi \va (lisinfcctMnl, 582 Holulion, 454 sulphaicr IchI,, I()2 Polaiocs, 1<)() HWCCi,, I'M) Poultry, (toinposilioii of, 'XI Pr(>c.ipit,!i(.ioii in ncwa|!;'' disiiosal, 542 Precipitins in scrum, 7'.I.S Preparation of food, (144 Preservation of food, 253 oheini(!al, 25(5 of milk, 114 chcMTiical, 1 IS Preserved (isli, .'{S Pressure, higli, o(Huipa(iona exposing (o, 7:37 Prevent ion of dissemination of infectious matter, G09 of malaria, 70G of yellow fever, 71 1 Probable duration of life, 759 Proportion of body measurements, 621 Protamines, 21 Proteids, 19, 99 in soil, 319 Proteins, 20 Proteoses, 21 Psychrometer, 299 Puerperal sepsis, immunization in, 811 Pulled bread, 183 Pumpkins, 201 Purification of water, 396, 404 algir in, destruction of, 412 limitations of, 401 Pyrocatechin test, 163 Q. Quarantine, 820 detention camps, 829 interstate, 826 municipal, 828 State, 826 Quicklime as disinfectant, 580 R. Rabies, milk affected by, 128 Race in vital statistics, 752 Radiation in ventilating, 486 Radishes, 199 Rain, 279 Rain-water, 363 stored, 3S2 Raspberries, 204 Rations, naval, 672 of soldier, various, 639 Rations, tro|)ical, 645 R(!cr(!ation, 764 Itecruit, <)!9 naval, (»71 ited meatH, 28 HiiductiiHCH, 105 RcdiKttion in narba^e diH{)OH!il, 550 iicnistrar'H retiirns, 747 ll(!KiiiatinK tcmpcratiin-, \'M) Residencr; in tro|)icH, (iS3 Respiralioii in active; exerclMC, 765 Rest, 7()4 Ribb(!s, 201 Touffuo, b(!(^f, 'M) ToxiiiH, 7S:} Traps for grc-'iso, 514 pluinhinfT, r,07, 510 seal of, 511, 516 ventilation of, 516 Travel ration, 641 Tri(;hina spiralis, 39 Trichinosis, 41 diagnosis of, 42 Trichocephalua dispar in water, 442 Tripe, beef, 30 Tropical dietary, 648 diseases, 688 hygiene, 681 rations, 645 Trousers, 629 Truffles, 205 Trypsin, 104 Tuberculin tests of cattle, 47 therapy, 812 Tuberculosis, air as carrier of, 293 animal experimentation in, 50 in animals, 46 in army, 666 danger from carcasses affected with, 49 immunization in, 811 milk affected by, 130 relation between human and bovine, 50 of soil to, 343 Tubers, 196 Tubs, laundry, 535 Turnips, 199 Typhoid fever, air as carrier of, 294 in army, 667 celery as bearer of, 64 crawfish as carrier of, 64 food as bearer of, 58 immunization in, 807 milk as bearer of, 139 relation of soil to, 343 water-cress as bearer of, 64 supplies infected with, 425 rates, influence of water supplies on, 426 54 U. l!i/t'itA-vif)r,KT rayH in purification of water, 403 Ihicinaria dufxifiialiH in wat\ good, 27 poisonous, 70, 76 Vegetaljli! fats, 195 foods, classification of, 177 marrow, 201 Vegetal)l(!3, disease transmitted by, 44 fruit products as, 201 Vegetation, effect of, on soil, 336, 337 on water, 397 Venereal disease in army, 670 Ventilating cowls, 479 pipes in plumbing, 508, 516 Ventilation, 473 aspiration in, 479 diffusion in, 476 filtration in, 493 gravity in, 476 heat conduction in, 486 inlets, 482 mechanical, 485 natural, 481 outlets, 482 perflation in, 479 radiation in, 486 rates, 475, 482 determination of, 493 space required, 475 of traps, 516 of vessels, 677 with heating, 485 Vermicelli, 183 Vessels, ventilation of, 677 Vinegar, adulteration of, 248 examination of, 248 Mnegars, 246 Vital statistics, 742 Vitiated air, effects of, 286 occupation exposing to, 723 W. Walnuts, 194 Waring system of irrigation, 547 Wasli basins, 530 Washing soda as disinfectant, 579 Wash-out closets, 525 850 INDEX. Wassermann reaction, SOO ^\■aste pipes, 509 \\'ater, 363 action of, on metals, 414 bacteria in, 379 diseases related to, 420 examination of, 444 bacteriolofiic, 462, 467 chemical 444, 467 inferences from, 459 gases in, 371 hardness of, 378 determination of, 453 removal of, 413 mineral contents of, disease and, 421 matters in, 377 organic matters in, 372 parasites in, 441 physical characters of, 3G7 determination of, 455 purification of, 396 by boiling, 404 chemical, 398 destruction of algse in, 412 by distillation, 404 by filtration, 404 by light rays, 403 limitations of, 401 removal of iron in, 414 reaction of, 369 determination of, 455 residue in, determination of, 453 sanitary classification of, 394 in soil, 332 sources of, 335 substances normally found in, 371 supplies, 382 filtration of, 406 military, 656 naval, 675 typhoid infection of, 425 vapor in air, 276 determination of, 276 Water-closets, 520 connections of, 529 disinfection of, 616 flushing apparatus for, 528 in ships, 680 Water-gas in illumination, 499 \\'atcr-proof blankets, 632 Weight, rlTcct of exercise on, 767 height and, 621 Wells, 386 deep, pollution of, 393 drainage area of, 391 pollution of, 391 Welsbach burners, 498 Werner-Schmidt test, 149 Wheat, 178 composition of, 179 flour, 179 adulteration of, 184 bleaching of, .185 preparations of, 180 Wheeling, 770 Whip worms in water, 442 Whiskey, 243 factitious, 244 White meats, 28 Wind, action of, 330 Wine vinegar, 247 Wines, 234 acidity of, 238 adulterations of, 396 analysis of, 238 classification of, 235 coal-tar colors in, 237 detection of, 239 composition of, 236 preservatives in, 237 detection of, 240 Wolpert's test, 309 Women, employment of, 740 Wool clothing, 628, 772 Work. 633 Yellow fever, prevention of, 711 relations of mosquitoes to, 707 of soil to, 348 Zinc, action of water on, 418 chloride as disinfectant, 581 food contaminated by, 267 in water, detection of, 458 Zymotic diseases, 754 V^>.;>; ;;^'sj^^<«5i$K*^^:*t^ .; jt^gj tSSSSSSSSSi "> ^^wgW^M >! ibhbbbhBBiI ■H ..■■rnm. * M'; ^.. yi,:'-,L>i^:aLi-:i-i^.