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 ANALYSIS 
 
 OF 
 
 Milk, Condensed Milk, 
 
 AND 
 
 INFANTS' MILK-FOODS. 
 
 J>r. JV. aJERBES.. 
 
 5F253 
 
CHEMICAL AND PHYSICAL ANALYSIS 
 
 — OF — 
 
 Milk, Condensed Milk, 
 
 — AND — 
 
 INFANTS' MILK-FOODS, 
 
 WITH SPECIAL REGARD TO 
 
 HYGIENE AND SANITARY MILK INSPECTION. 
 
 A Laboratory Guide, developed from Practical Experience^ 
 
 INTENDED FOR 
 
 Chemists, Physicians, Sanitarians, Students, etc. 
 
 By Dr. NICHOLAS GERBER, 
 
 Manager of the American-Swiss Milk Product Company (Limited) in New York ; Member of the 
 Chemical Societies of Berlin, New York, Paris, etc. 
 
 Translated fro?n the Revised German Edition, and Edited by 
 
 Dr. HERMANN ENDEMANN, 
 
 Editor of the Journal of the American Chemical Society ; Member of the Chemical Societies of 
 Berlin, New York, etc., etc. 
 
 ILLUSTRATED BY 19 PLATES. 
 
 New York, 1882. 
 
Entered according to Act of Congress, in the year 1882, by the proprietors, 
 Dr. NICHOLAS GERBER, of Little Falls, N. Y., 
 Dr. HERMANN ENDEMANN, of 3^ Nassau St., New York City, 
 in the Office of the Librarian of Congress, at Washington. 
 
 4^/ 
 
 ^J 
 
 LEHMAIER & BRO. PRINT, 
 95. 97, FULTON STREET, N. Y. 
 
EDITOR'S PREFACE. 
 
 In preparing this book for the English-speaking public, the 
 undersigned desires to state that he has undertaken this task for 
 the purpose of supplying a long-felt want. Most books published 
 of late contain merely a collection of all the methods of analysis, 
 or the selection of a number, put side by side without criticism. 
 
 The book in its present shape is a laboratory guide, which 
 enables even beginners, and all such who cannot make the subject 
 of milk analysis a speciality, to cope with this otherwise compli- 
 cated task. 
 
 The selection of the proper method of analysis is taken off 
 their hands and has been supplied by a man of practical experi- 
 ence, who has for many years made this subject a specialty. 
 
 Even chemists will find this book valuable, the more so as they 
 are the best able to judge the advantages derived from the proper 
 selection of the method adapted for the execution of an analysis. 
 
 The original has been carefully revised and many of the 
 plates which illustrate the work have been substituted by better 
 ones taken from the best publications on this subject, while others 
 not contained in the original have been added. 
 
 IT. ENDEMANN, Ph.D. 
 
 New York City, January, 1882. 
 
PREFACE. 
 
 The undersigned has been engaged, scientifically and practically, 
 in the dairy industry in all its branches for a number of years, and 
 thus has had, frequently, occasion to seriously feel the want of a 
 uniform method of analysis for milk and its products, which would 
 not only satisfy practical wants, but would also possess scientific 
 accuracy. 
 
 The author has made it his task to present in this small volume 
 a short and exact method of analysis for the examination of the 
 various milks and infants' milk foods, and hopes to soon complete 
 his undertaking by the issue of a similar volume which shall com- 
 prise the examination of the otiier milk products and such other 
 substances as are employed in the dairy industry. 
 
 As may be seen by the contents, undersigned has not endeav- 
 ored to criticise the various older methods, as yet generally in use, 
 as this would have been beyond the range of his self-imposed task. 
 
 Moreover, there is no want of such books. Undersigned 
 therefore refers to those previously published by Yieth, Raden- 
 hausen and himself. 
 
 It is a peculiar fact, that even in the latest chemical, medical 
 and pharmaceutical works, old and abandoned methods are con- 
 tinually republished, the authors considering it aj^parently unnec- 
 essary to test them for their reliabilit3\ 
 
 Likewise, in the adducing of average figures regarding the 
 composition of milk, these authors seem to be prepossessed in 
 favor of the oldest and least exact investigations, while they 
 neglect the more exact and, therefore, more valuable examinations 
 of the present period. 
 
This copying without examination (book manufacturing) is 
 especiallj dangerous in analytical chemistry, and more so if the 
 results must stand test before a court of justice, which in examina- 
 tions of this kind is frequently required. 
 
 The position of an expert who has employed acknowledged 
 inaccurate methods for his examination, is certainly not an envia- 
 ble one. 
 
 The author of this small volume has therefore collected therein, 
 for the first time, those methods which are acknowledged as being 
 the best for scientific and practical purposes. 
 
 They excel the methods known before 1877. 
 
 1st. For their greater accuracy. 
 
 2d. For greater simplicity. 
 
 3d. For cheapness and economy of time. 
 
 The views expressed in this book no doubt may be modified in 
 time, and undersigned will, therefore, at all times, be pleased to 
 receive suggestions from others. 
 
 Dk. NICHOLAS GERBER, 
 
 Manager of the Ameiican Swiss Milk Product Co. {Limited), 
 New York City. 
 
 Little Falls, N. Y., January, 1883. 
 
CONTENTS. 
 
 
 
 PAGE. 
 1 
 
 NORMAL COWS' 
 
 General Definition 
 
 Colostrum 
 
 MILK. 
 
 . 3 
 
 Market Milk 
 
 
 . 8 
 
 Physiological and Other Causes 
 Influencing the Secretion. 
 
 Period of Lactation 3 
 
 Age of Cow 4 
 
 Cows in Heat 4 
 
 Race and Individuality 4 
 
 Food and Treatment 5 
 
 Seasons 5 
 
 Influence of Temperature 5 
 
 Influence of Weather 5 
 
 Exercise 5 
 
 General Physical Properties 6 
 
 Chemical Constittutits 6 
 
 Composition of other Milk Compared 
 
 with Cows' Milk 8 
 
 PHYSICAL ANALYSIS OF 
 MILK. 
 
 Color— '^ormaX 9 
 
 Red 9 
 
 Yellow 10 
 
 Blue 10 
 
 Consistency— "^ormsiX 11 
 
 Watery 11 
 
 Colostrum 11 
 
 Phlegmy and Stringy. . 12 
 
 Sandy 12 
 
 Of/^r— Normal 13 
 
 Aromatic 13 
 
 Putrid 13 
 
 Medicinal 13 
 
 Trtj/^— Normal 13 
 
 Bitter 14 
 
 Medicinal 14 
 
 Putrid 14 
 
 Sour 14 
 
 Microscopical Examination. 
 
 PAGE. 
 
 Normal Milk (with plate) 14 
 
 Butter Globules 14 
 
 Colostrum (with plate) 15 
 
 Pus and Epithelial Cells (with plate). 16 
 
 Lower Organisms 16 
 
 Specific Gravity. 
 
 Definition 17 
 
 Apparatus for Its Determination. . . 17 
 Weighing in a Flask (Pycnometer) 
 (with table.) 18 
 
 CHEMICAL ANALYSIS OF 
 MILK. 
 
 General Rules 21 
 
 Reaction of Milk 22 
 
 Determination of Water and Solids. 22 
 
 Determination of Ashes 23 
 
 Detei-mination of Phosphoric Acid . 23 
 Determination of Albuminates and 
 
 Fat (with plate) 24 
 
 Determination of Milk Sugar 27 
 
 ABNORMAL COWS' MILK. 
 
 Colostrum 30 
 
 Poisoned Milk 31 
 
 Milk Containing Medicines . 33 
 
 Milk as the Cause of Disease (2 plates) 33 
 
 Typhus 34 
 
 Scarlatina 34 
 
 Tuberculosis 34 
 
 Anthrax 35 
 
 Aphtha epizootica (with plate) 35 
 
 Ittfluence of Food, etc 37 
 
 Potato Distillery Swill 37 
 
 Brewers' Grains 38 
 
 Milk in Fermentation 38 
 
 Pus 38 
 
 Mucus 38 
 
 Adulteration of Cows' Milk 38 
 
 Watery Milk , 39 
 
 Normal Market Milk 40 
 
 Sour Milk 41 
 
 Foreign Substances 41 
 
 Preservatives 42 
 
Vlll 
 
 MILK OF OTHER ANIMALS. 
 
 PAGE. 
 
 Goats' Milk 44 
 
 Sheep's Milk 44 
 
 Asses' Milk 45 
 
 Mares' Milk 45 
 
 CONDENSED AND PRESERVED 
 MILKS. 
 
 Condensed Milk, with Sugar 47 
 
 Physical Analysis 48 
 
 Chemical Analysis 49 
 
 Other Milk Preserves 50 
 
 Hygienic Demands 51 
 
 WOMAN'S MILK. 
 
 Various Influences upon the Se- 
 cretion 52 
 
 Taking the Sample 55 
 
 Physical Examination (2 plates) 55 
 
 Chemical Analysis 57 
 
 Milk from the Breasts of Newly-born 
 Infants 60 
 
 INFANTS' MILK FOODS IN 
 POWDER. 
 
 History, Definition 61 
 
 Physical Properties 61 
 
 Microscopical Examination (5 plates). 62 
 
 Chemical Analysis 65 
 
 Determination of Water 65 
 
 of Ash and Phos- 
 phoric Acid 66 
 
 Determination of Fat 66 
 
 "' of Soluble Car- 
 bohydrates 67 
 
 Determination of Insoluble Car- 
 bohydrates 68 
 
 Determination of Albuminates. 69 
 Reports on Milk Foods 69 
 
 Infants' Milk Foods in Vowd^h— Continued. 
 
 PAGE, 
 
 Hygienic Demands of ike Manufac- 
 turers 70 
 
 GOVERNMENT CONTROL OF 
 THE MILK SUPPLY 73 
 
 Determination of Specific G7-avity. ... 76 
 Quevenne's Lactodensimeter and 
 
 the Lactometer (2 plates) 78 
 
 And 2 tables 81 and 82 
 
 Examination of Skimmed Milk 83 
 
 Stable Test 84 
 
 Estimation of the Quality of 
 Milk by the specific gravity. . 85 
 Determination of the Fat 
 
 (with plate and table) 85 
 
 Properties of Normal Cows' 
 
 Milk and Market Milk 92 
 
 The Aim of Governmental 
 Control of the Quality of 
 
 the Milk Supply 92 
 
 General Rules for a Rational 
 
 Milk Inspection 94 
 
 In Cities 94 
 
 In the Stable 96 
 
 Proposition stating the Main 
 Points for an Ordinance 
 Regulating the Sale of 
 
 Milk in Large Cities 97 
 
 Propositions for Regulations 
 Governing Producers of 
 Milk and Milk Dealers 98 
 
 LIST OF APPARATUS AND 
 CHEMICALS REQUIRED 
 FOR THE ANALYSIS OF 
 MILK and INFANTS' MILK 
 
 FOODS 100 
 
INTRODUCTION. 
 
 Of all articles of food, none requires so much of our attention as 
 milk. While it engages the scientist on account of its relation to 
 physiology and pathology, the public are interested in milk by 
 the place it occupies as a food of so general application, and by 
 the fact that it forms an important article of commerce and a base 
 for manifold industries. Cows' milk, and of late, infants' milk-foods 
 and condensed milk, are of more special interest by the fact, that in 
 the case of an insufficient or wholly wanting supply of breast milk, 
 they are destined to form, for a considerable period of time, the 
 sole food for infants. We should, therefore, be well acquainted 
 with the quality of these articles as they reach the consumer. 
 
 To insure a supply of healthy and unadulterated food, the gov- 
 ernments of many countries have passed laws for the punishment 
 of adulterations, and in order to detect them, have taken the ex- 
 amination of the various food substances in hand. Milk, being 
 more exposed to adulteration than many other foods, has of late re- 
 ceived a considerable share of this attention. 
 
 The control which a government exerts, protects the public 
 against fraud by preventing the sale of goods of inferior value at 
 high prices ; but more important is the protection which, by gov- 
 ernment interference, is gained for the health of the consumer by 
 the absolute prevention of the sale of specifically altered, spoiled 
 and adulterated milk. The poorer and working classes, and espec- 
 ially the children, suffer most, if the milk is not of the best 
 quality. 
 
 Chemical analysis, even if carried out according to the best ap- 
 proved methods, would not bring us nearer to a satisfactory solu- 
 tion of this question, unless exact science has thoroughly investi- 
 
gated this field, and has, based upon such investigation, determined 
 the limits of the composition of a normal food. Without this, the 
 position of an expert before a court of justice would be untenable. 
 
 The examination of the milk differs according to the question 
 which is to be decided. It may be made to ascertain the relative 
 quantities of the normal constituents of milk, or to determine the 
 admixture and nature of foreign substances which may, or may not, 
 be dangerous to the health of the consumers. 
 
 Each chemical examination is preceded by an examination with 
 the senses — eye, smell and taste. Hereby many admixtures and 
 qualities of milk may be directly ascertained, which, for the fol- 
 lowing chemical examination, may not only furnish hints, but 
 which may serve to corroborate the results obtained by it. 
 
 The physiological part of the milk question has been included 
 for the reason that in cases before tiie courts such questions fre- 
 quently arise, and because the knowledge of them will aid in the 
 formation of a more correct opinion. 
 
 To facilitate the examination of milk and milk products, a num- 
 ber of plates from microscopic objects have been introduced into 
 the text. 
 
 The chemical and physical analysis of infants' milk-foods and 
 their hygienic value, has in no previous work been treated as 
 thoroughly. The method of analysis given is based upon the exact 
 investigations made by Dr. P. Radenhausen and the author, and is 
 given in this work in an improved shape. The author desires to 
 recommend to the consideration of the medical profession the 
 chapter entitled, " Hygienic demands upon the manufacturers of 
 infants' milk-foods." Humanity demands that we know and ex- 
 amine which foods should be recommended and can be relied upon. 
 Much hardship and sickness of mankind can be prevented, if by 
 rational food the organism, especially of infants, be strengthened. 
 The author sincerely desires that the contents of this book will not 
 fail to improve our knowledge of food hygiene, and thus fulfil the 
 expectations with which it has been written. 
 
NORMAL COWS' MILK. 
 
 GENERAL DEFINITION. 
 
 Milk is the secretion of tlie mammary glands, in which it is 
 produced by certain processes of diffusion from the blood, accom- 
 panied by a dissolution of the gland cells. Lactation commences a 
 few days after birth, and lasts for a period of time, the length of 
 which depends on various circumstances. C. Yon Yoit says : 
 "Milk consists of liquified cells. All mammals are, therefore, 
 carnivorge, for they sustain themselves by consuming a portion of 
 .the body of their mother." 
 
 Colostrum : The first milk yielded by a cow, either before, or 
 from the fourth to seventh day after calving, is called 'beastings,' 
 or ' colostrum. ' 
 
 Market iniUc is generally the milk of several cows mixed. For 
 the examination of the milk, as it reaches our markets, this is 
 a point of great importance — many irregularities, frequently met 
 with in the milk of single cows, being thereby compensated. 
 
 The substances composing milk are for all mammals essentially 
 the same. So is the general character of the milks. The differ- 
 ence of the various milks consists, therefore, only in the respective 
 quantities in which the constituents are present, as also in taste, 
 flavor and color. 
 
 Physiological and other Causes Influencing 
 the Secretion. 
 
 The period of lactation generally lasts three hundred days, 
 one cow giving during this time from six to ten quarts of milk 
 per day. When the animal ceases to give milk, we say that it 
 stands dry. 
 
The following circumstances are of influence on lactation : 
 
 Age of cow : When a cow has its first calf, it does not pro- 
 duce the maximum quantity of milk, but the quantity increases 
 from year to year until a certain limit is reached, when, with fur- 
 ther increasing age, the quantity is reduced, at first slowly and 
 more quickly later on. 
 
 The age to which it pays to keep cows for milking differs 
 according to individuality, race and treatment. It is generally 
 accepted that cows are the most profitable from their third to their 
 tenth year. 
 
 Cows in heat: "We know but little of the changes which oc- 
 cur in milk at the return of the periods when cows get in heat. 
 
 From the feeding experiments made by G. Kuehn and Fleischer, 
 a characteristic change of the milk, during these periods, cannot be 
 deduced. Such milk, it has been stated, will sometimes curdle on 
 boiling. A normal course of this process, which lasts but a few 
 .days, should not influence normal lactation for any length of time. 
 
 It may be remarked that also cows which have undergone the 
 process of castration, may produce milk. It is, however, not con- 
 sidered profitable to keep such cows longer than two years. They 
 fatten up rapidly, and their milk-producing qualities suffer in con- 
 sequence. 
 
 Race and individuality : Good milk-producing qualities de- 
 pend principally on a strong and healthy development of the udder. 
 A defect in this can never be remedied by the best and most 
 nutritious food. The yield and quality of the milk depends directly 
 on individual properties of the animal and, therefore, also on its 
 race. 
 
 Comparative investigations regarding the yield and quality of 
 the milk of different races have frequently been made, but they are 
 incomplete and little trustworthy. They have either been under- 
 taken with but few animals for a longer period, or if really on a 
 large scale, but for a short period. In some cases select stock has 
 been observed for longer periods. Average figures deduced from 
 such incomplete and heterogeneous observations are, therefore, of 
 little value. The yield and quality of the milk of various races and 
 breeds of cattle, cannot be determined without the collection of 
 copious and well selected statistics in the countries of which these 
 cattle are indigenous. Few investigations have been made to 
 which chemistry has contributed as largely as it should have done. 
 
Food and treatment: To keep the production of milk dur- 
 ing the whole period of lactation in a satisfactory state, good 
 housing and treatment, and food answering the circumstances, as 
 regards quantity, volume, preparation and chemical composition, 
 are requisite. 
 
 It may be regarded as a fact, that the quantities of milk and 
 butter are increased with the amount of nitrogenous material in 
 the food. Uniformity of treatment and food are to be recom- 
 mended, and sudden changes in this regard be avoided, since ex- 
 perience has proved that they are invariably followed by disadvan- 
 tageous influences upon the secretion of milk. The production of 
 milk is greatly fostered by healthy water of an even temperature, 
 neither too high nor too low, charitable treatment of the cattle, and 
 punctuality in attending to their wants. 
 
 Seasons : The yield of milk differs with the changes of weather 
 and food in the several seasons. Most, but often also thinnest, 
 milk is produced during the spring, on account of the food which 
 then consists mainly of young luxurious herbs. The more nourish- 
 ing after-growths on the meadows and fields during summer and 
 fall, as also the dry food during winter, are the cause of a smaller 
 yield of milk which, however, is richer. 
 
 Influence of temperature: The yield of milk of the cows 
 differs with the geographical latitude. From this alone we may 
 assume that the temperature exerts a decided influence. An aver- 
 age annual temperature of 15° C. is considered to be the most ad- 
 vantageous. Too high temperatures (in the stable) debilitate and 
 predispose the cows to colds, influence disadvantageously the yield 
 of milk, and sometimes even its quality. 
 
 Influence of tveather : Eain, humidity of air and winds doubt- 
 less exert an influence on the general well-being and the various 
 physiological processes. Exact investigations as regards the in- 
 fluence of these meteorological phenomena on yield and quality of 
 milk, have not yet been made. 
 
 Exercise : Moderate exercise in the open air and on the pas- 
 ture is advisable. Hard work and long journeys diminish yield 
 and quality of milk. Milk of such cows is apt to curdle on 
 boiling. 
 
 The constitution of the animal is reproduced in the milk it 
 yields. The milk of stronger animals is, therefore, on the average, 
 
richer than the milk from the weaker. The use of inferior food 
 and unhealthy water, and certain diseases, cause also the produc- 
 tion of an inferior milk. Particulars regarding this will be given 
 in the chapter on " Abnormal cows' milk." 
 
 General Physical Properties. 
 
 Milk is an opaque, white or more or less yellowish fluid. Be- 
 tween the lingers it feels greasy. It has a weak, mild, sweetish 
 taste, and flavor to con-espond. The raicroscoj^e reveals the 
 presence of innumerable small <4lobules suspended in a pelucid fluid. 
 Sometimes epithelial cells, gland cells and lower organisms may 
 be recognized. The specific gravity varies from 1.025 to 1.038. 
 
 Chemical Constituents. 
 
 I. The main constituent of milk is tvater, of which, on the 
 average, 87.5 per cent, is present. 
 
 II. The albitminates of milk are, according to the latest inves- 
 tigations of Danilewsky and Kadenhausen, as folloAVS : 
 
 1. Albumen, probably identical with blood albumen. 
 
 2. Protalbumens, which Danilewsky obtained some time since 
 
 by peptonizing various albuminates with alkali and pan- 
 creatine. These give to casein its acid character. Albu- 
 men and the protalbumens together form the so-called 
 casein, which is, therefore, not a single body,but a mix- 
 ture. 
 
 3. Orropkotein, which is an albumen with albuminoid char- 
 
 acteristics. 
 
 4. Synto-protalbumens, which, according to Danilewsky, are 
 
 obtained from albuminates by the action of acids and 
 pepsin. 
 
 5. Peptones, or digested albuminates, were found by D. and 
 
 R. in the serum of coagulated milk, together with the ex- 
 tractive substances. 
 
 Milk contains, therefore, according to Danilewsky and 
 Kadenhausen, large quantities of incompletely digested 
 albuminates which, according to their characteristics, 
 were called jorotalhtmens and synto-protalbumens. 
 
The protalhumens are acid, bodies, soluble in 50 per 
 cent, alcoliol, insoluble or little soluble in water. At 
 ordinary temperature they saturate alkalies but not acids. 
 
 The sy7ito-])rotalhumens have a neutral reaction. At 
 ordinary temperature they do not unite with alkalies, 
 but mineral acids. They act, therefore, as bases. They 
 are insoluble in water, soluble in hot 50 per cent, al- 
 cohol, from which solution they may be obtained on 
 cooling. The main constituent of the albumen of former 
 investigation, is identical with the stroma albumen which 
 envelopes the butter globules. 
 
 These investigations give us an entirely new picture 
 of the constitution of milk. The hitherto known casein, 
 albumen and lacto-protein, do not exist, and these names 
 should, therefore, not be used in repoi'ting the results of 
 the analysis ; instead, it is better to class them under the 
 general denomination of " albuminates." 
 
 III. The milk-fats appear as minute globules which can be re- 
 cognized merely with the aid of the microscope. Each of these 
 globules is surrounded by a thin film of stroma albumen (not ca- 
 sein). Their diameter varies considerably. Specific gravity and 
 melting point vary likewise with race and quality. 
 
 The fats are triglycerides, derived mainly from stearic, jpal- 
 mitinic and oleic acids ; aside from these the following are to be 
 mentioned : myristine, hutine, hutyrine, ca])ronine and capryline. 
 The chemical composition varies considerably with the food on 
 which the animal is kept, likewise the color, which, during the sum- 
 mer is yellow, while during the winter it appears more white. 
 Fresh milk-fat is a semi-fluid mass of faint taste and odor. 
 
 IV. Milk stigar (CisHagOu -f- HjO) crystallizes when pure in 
 rhombic prisms, which are not changed when kept in dry air. It 
 feels hard and gritty between the teeth. It is insoluble in absolute 
 alcohol and ether, soluble in 6 pts. of cold, and 2.5 pts. of boiling 
 water. Its taste is only slightly sweet. Its si3ecific gravity varies 
 from 1.543 to 1.548. In the polariscope it shows birotation. 
 
8 
 
 V. The Milk ashes consist, according to Fleischmann, in the 
 average, of 
 
 Phosphoric anhydride, (PjOj) 28.31 
 
 Chlorine, (CI) 16.34 
 
 Lime, (CaO) 27.00 
 
 Potassa, (KjO) 17.34 
 
 Soda, (Na,0) 10.00 
 
 Magnesia, (MgO) 4.07 
 
 Iron sesquioxide, (FcjOg) 0.62 
 
 103.68 
 Deduct for corresponding CI, 3.68 
 
 100.00 
 The quantity of salts in the milk ranges from 0.4 to 0.8 per 
 cent. They contain generally all those nutritive salts which have 
 been taken with the food. 
 
 YI. The gases of milk are carbon-dioxide, nitrogen and 
 oxygen, the first predominating. They are of little importance. 
 
 YII. The extractive substances: They have been found in 
 small quantities in the milk, and include the following substances : 
 urea, kreatinine, leucine, tyrosine and lecithine. 
 
 VIII. In small quantities, coloring substances, and such which 
 
 give to milk its characteristic flavor. They vary with the season 
 
 and food, and are met with in larger quantities during the summer 
 
 season. 
 
 Composition of Other Milks compared 
 
 ^vith Cows' Milk. 
 
 Milks from other animals differ from cows' milk in composition 
 according to the position occupied by the animals in the zoological 
 system, and according to their food (herbivora or carnivora). 
 
 The following tabulated statement gives average values derived 
 from a series of exact analyses of normal milks : 
 
 Species. Sp. gr. 
 
 White -woman 1.025-1.035 
 
 Negro " 1.025-1.037 
 
 Milk of single cows.. 1.025-1.038 
 
 Mare 1.031-1.036 
 
 Ass 1.030-1.036 
 
 Goat 1.028-1.036 
 
 Sheep 1.034-1.042 
 
 Hog 
 
 Camel 1.035-1.042 
 
 Of the milk of other animals only a few, and then often incom- 
 plete analyses of doubtful value could be found ; their mention 
 has therefore been omitted. 
 
 Water. 
 
 Salts. 
 
 Albumen. 
 
 Fat. 
 
 Sugar 
 of Milk. 
 
 
 
 
 
 88-90 
 
 0.20-0.50 
 
 2.0-4.0 
 
 2.0-4.0 
 
 4.0-6.0 
 
 86-90 
 
 0.30-0.75 
 
 3.0-4.0 
 
 4.0-5.0 
 
 5.0-6.0 
 
 86-89 
 
 0.50-0.75 
 
 3.5-5.0 
 
 3.0-4.5 
 
 3.5-5.0 
 
 90-92.5 
 
 0.25-0.50 
 
 1.5-3.0 
 
 0.5-1.5 
 
 4.5-6.5 
 
 89-92 
 
 0.25-0.50 
 
 1.5-3.0 
 
 1.0-2.5 
 
 4.5-6.0 
 
 85-87 
 
 0.50-0.75 
 
 4.0-6.0 
 
 3.5-5.0 
 
 3.5-5.5 
 
 80-85 
 
 0.50-1.25 
 
 4.0-6.5 
 
 4.0-7.0 
 
 4.0-6.0 
 
 82-85 
 
 0.75-1.25 
 
 5.0-7.0 
 
 5.5-7.0 
 
 2.0-5.0 
 
 85-87 
 
 0.50-0.75 
 
 3.0-4.0 
 
 2.5-3.5 
 
 5.0-6.5 
 
Physical Analysis of Milk. 
 
 COLOR. 
 
 Normal : Milk in its normal state is opaque white to yellow. 
 During winter it is more white, while in summer the color is more 
 or less yellow, produced by the richness of the food in chloro- 
 phyll. Plants containing certain coloring substances, may impart 
 certain hues to the color of milk. Peculiarities of color may, how- 
 ever, be produced by other causes. 
 
 B,ed: Red milk is mainly caused by a general diseased condition 
 of the cow, and has been found in cases of anthrax, as an accom- 
 panying symptom of red murrain, and after the use of acrid and 
 resinous remedies. 
 
 Such milk contains many blood corpuscles and gives on standing, 
 a sediment. 
 
 Milk appears sometimes irregularly colored, the color appearing 
 in streaks or attached to coagulated masses, which collect rapidly 
 at the bottom of the vessels. The occurrence of such milk is fre- 
 quently confined to certain parts of the udder, and is then caused 
 by congestion, inflammation, and mechanical injuries inflicted upon 
 the udder. 
 
 Detection : Blood corpuscles are easily detected by the micro- 
 scope. They are recognized by their yellowish color and their 
 shape. They present themselves as small disks, slightly indented 
 in the centre. This can best be seen on single corpuscles. They 
 are frequently united, forming bodies similar to rolls of specie. 
 The accompanying cut represents milk containing blood corpuscles. 
 
10 
 
 Milk containing blood will, on boiling, change its color from red 
 to brown, since hsemoglobine is decomposed on the application of 
 heat. Rennet and madder will color milk uniformly, and the color 
 thus produced does not undergo change on boiling. 
 
 Yellow: The yellow color may be produced by certain vegetable 
 pigments. It is said to also accompany certain changes which are 
 characterized by the formation of stringy, skinny and lumpy 
 coagula, which sink to the bottom on standing. The supernatant 
 milk appears opalescent and stringy . This color is also observed 
 in jaundice. Cause: congestion and inflammation of the udder. 
 
 Blue : A blue color in milk has rarely been observed at the 
 time of milking, unless it be produced by blue vegetable pigments. 
 The milk is in this case uniformly colored. Milk may, however, 
 after some time turn blue under the influence of certain ferments. 
 On the surface of the milk or the cream, beautiful indigo-blue 
 spots appear which gradually enlarge. After some time the color 
 ceases to increase, and then, even with the naked eye, the growth 
 of fungi can be observed. Already long before this the micro- 
 scope shows the presence of mycelium, vibrios and bacteria in such 
 milk. The original cause of this milk infection has been traced to 
 the growth of a certain fungus described by Fuerstenberg (see cut), 
 whereby the constituents of the milk are decomposed, giving rise, 
 as some believe, to the formation of aniline blue (triphenyl- 
 rosaniline). 
 
n 
 
 This has as yet not been established as a certainty. Spectro- 
 scopic investigations, however, point to a dye-stuff standing in near 
 relati6n to the aniline djes. When and why this fungus makes its 
 appearance is not known. This milk disease can be banished by 
 extreme cleanliness and the use of disinfectants. 
 
 As to the duration, appearance and propagation of this ab- 
 normity in one place, or in comparison with other places, no rules 
 could be established. It has likewise been found that the use of 
 preventatives was not always followed by the same results. 
 
 It is therefore easily understood why so many theories as to its 
 cause should be given. While one looks for the cause to the cow, 
 others find it in the food, until we know now that this abnormity 
 is produced by a ferment. (Peterson, Forschungen, 1881, p. Y8.) 
 
 CONSISTENCY. 
 
 Normal milk : Normal whole milk is a fatty, homogeneous, 
 opaque liquid, which is always heavier than water. Its consistency 
 is influenced by the milking, the first milk being always more 
 watery than the last. This circumstance is of considerable im- 
 portance when an examination is to be made of the milk furnished 
 by a certain animal, or all such as are housed together or supply a 
 dairy. The following abnormal conditions have been observed : 
 
 Watery milk : Watery milk is strikingly fluid and of a bluish- 
 white color. It is poor in solids, especially fat, and its specific 
 gravity is below the normal. 
 
 Causes: Indigestion, unsuitable food and housing. Indigestion 
 may be caused by the animal getting in heat. This normal exist- 
 ence of watery milk must be well considered in milk inspection. 
 It will rarely affect more than a few cows in the same stable at one 
 time, and if such milk is mixed with the normal milk of the other 
 cows, its characteristics, notably its low specific gravity, will be 
 compensated. It can therefore but rarely be the cause of serious 
 complaints. 
 
 Colostrum: Colostrum, by milkmen and farmers called beast- 
 ings, is decidedly phlegmy and glutinous. It possesses a peculiar 
 stale taste. On boiling, it curdles. Its specific gravity is very 
 high =1.08, it being very rich in solids. This milk is not an 
 article of trade. 
 
12 
 
 PJUegmy and stringy milk shows its characteristics only some 
 time after milking. It is thick and of flat taste, and shows its 
 stringy consistency if it is observed while it runs from the finger 
 after immersion. It creams slowly, and it is difficult to obtain 
 butter from it, which, when obtained, has a disagreeable taste. 
 Investigations regarding this process are incomplete, but it seems 
 that it is produced by some process of fermentation. Phlegmy 
 milk is said to curdle sooner than normal milk, the curd presenting 
 likewise an abnormal appearance and phlegmy consistency. 
 
 Such milk is said to infect normal milk. Its occurrence is caused 
 by indigestion, the use of poor and spoiled food, colds, and, accord- 
 ing to the latest investigations, also inefiicient ventilation of the 
 dairies. 
 
 In Norway, Sweden and Finland, an herb, Pinguicula vulgaris, 
 is added to the milk as a preservative. It is known to make milk 
 likewise stringy. 
 
 Sandy milk : Sandy milk contains solid mineral granules, 
 which are often so large and occur in such quantities, that the teats 
 become clogged. 
 
 Fuerstenberg, who examined such milks very thoroughly, distin- 
 guishes three kinds of milk stones or galactites. 
 
 1. Keal galactites consist of small granules, around which 
 amorphous salts of the alkaline earths have formed in concentric 
 layers. They are in shape globular, elongated, and occasionally 
 angular. Their surface is either smooth or rough, and their color 
 whitish to gray. In size they range from the size of a millet grain 
 to the size of a bean. 
 
 2. PsEUDO GALACTITES are in appearance similar to the former ; 
 they consist, however, of a hollow and compact curd of casein, 
 which is covered with crusts of salt. 
 
 3. CoNCREMENTS are amorphous, comparatively large, irregularly 
 shaped masses of organic matter, without concentric structure. 
 Their surfaces are rough white and lustreless like chalk. When 
 brought in water they swell and become soft. 
 
 Cause: Food and water, rich in salts of the alkaline earths, es- 
 pecially lime. 
 
13 
 
 Chemical composition, according to Fuerstenberg : 
 
 Galactites. 
 Real. Pseudo. Concre- 
 ments. 
 
 Calcium carbonate 91.03 92.30 17.45 
 
 Phosphates of alkaline earths 1.13 2.78 55.98 
 
 Fats 1.30 0.93 2.60 
 
 Other organic substances 5.40 3.14 18.55 
 
 "W"aters 1.14 o.85 5.83 
 
 Specific gravity 2.192 2.281 2.1 14 
 
 ODOR. 
 
 Normal: Milk possesses a peculiar odor, especially at the 
 time when it comes from the udder. 
 
 This is similar to the exhalation of the skin, and must not be 
 confounded with the milk flavor or aroma. It seems to be a pe- 
 culiar substance, and not to belong to one of the recognized con- 
 stituents of milk. 
 
 Milk filtered over animal charcoal is said to lose this smell. 
 It is therefore considered a substance for itself. 
 
 This animal odor is stronger during the heat of summer than 
 in winter time, and is apt, if present in quantity, to adhere even to 
 the preparations manufactured from milk. Milk should, there- 
 fore, be frequently aired to free it from this odor. 
 
 Aromatic : The essential oils of certain herbs contained in the 
 food are also easily recognized by the peculiar flavor which they 
 impart to milk. 
 
 Putrid : Putrid decomposition of milk has been observed as 
 consequence of untidy handling, keeping, and feeding with tainted 
 food and crude rancid bone dust, which at one time had been re- 
 commended as tending to increase the yield of milk. The cream 
 of such milk is o3-color, and breaks, in consequence of ascending 
 gas, which contains sulphuretted hydrogen. 
 
 Medicinal odor : An abnormal odor in milk may also be 
 caused by the odor of substances contained in food or medicines. 
 
 TASTE. 
 
 Normal ; Normal milk has a mild, sweetish taste. That cows' 
 milk does not taste like goats' milk, is owing to the peculiar odor 
 which is observed when it is tasted. 
 
14 
 
 Bitter : Bitter milk developes its taste onlj some time after it 
 was uiilked, and is accompanied by souring. The chemical changes 
 which take jDlace in such milk are not known, but the development 
 of gas seems to indicate a fermentation, the whole being, perhaps, 
 merely an incipient state of putrid decomposition. 
 
 Milk is said to become bitter also after the feeding with bitter 
 herbs, like dbsynthum. 
 
 Medicinal: Medicines may likewise impart to milk a pe- 
 culiar taste. 
 
 Futrid: The taste of milk in putrid fermentation. 
 
 Sour: Milk sours most frequently in sultry weather during 
 the summer. It may also be caused by diseases of the udder, or 
 when the cows have not been completely milked. Such milk cur- 
 dles when heated. 
 
 The Microscopical Examination. 
 
 This examination is to determine qualitatively whether a milk 
 is normal, diseased, or partially adulterated. For the construction 
 and use of the microscope we must refer to such works as treat 
 this branch of science as a specialty. 
 
 Normal milk: Milk, like blood, is an emulsion containing 
 some substances in solution, while others, the so-called milk globules, 
 are held in suspension, thus producing the color and opacity pe- 
 culiar to milk. 
 
 Butter globules: The butter or milk globules are highly re- 
 fracting globules, with an average diameter of 0.017 to 0.025 m.m. 
 
16 
 
 They appear with well marked outlines, dark at the edges, and 
 bright in the centre. They are simply fat globules which are pre- 
 vented from uniting by being immersed in milk plasma, which con- 
 tains casein in a swelled state. We distinguish three sizes of glob- 
 ules. 
 
 1. The very large^ and comparatively lightest, which, on ac- 
 count of their larger volurae, rise first, and form the first cream 
 on the milk. They are said to contain the fats of lowest melting 
 points. 
 
 2. The medium size form the main constituent of a good milk. 
 ^3. The smallest, of which good milk contains but few, and 
 
 poor milk large quantities. 
 
 "White milk contains more of these butter globules than blue 
 milk. 
 
 A normal milk should contain these globules moderately dense ; 
 they should be well-formed and separate, and should form the only 
 shaped portion of the milk. Milk of older cows is generally richer 
 in large globules. 
 
 If the majority of the globules is small and poorly shaped, it 
 indicates that the milk is poor in fat, and lacks in nutritive 
 qualities. 
 
 Watered and skimmed milk : The watered milk contains 
 the fat globules in the same proportion, as far as size is concerned, 
 as they are found in normal milk. The number of globules in the 
 field differs according to the quantity of water added. 
 
 Skimmed milk generally contains none of the larger butter 
 globules, these having been removed with the cream. 
 
 Value of microscopical examination : The value of milk 
 can never be determined by means of the microscope. Author 
 concurs here with Yieth, who says : " The microscopical exam- 
 ination of milk may, under circumstances, furnish valuable indica- 
 tions, il used for the detection of abnormal qualities in appearance 
 or behavior, or the determination of foreign substances added to 
 the milk. As a control for the determination of the fat, it has no 
 more value than other, even the best optical methods." 
 
 Colostrum corpuscles : Colostrum corpuscles are globules of 
 from four to five times the diameter of the fat globules. They 
 consist of proto-plasma which encloses fat globules. Occasionally 
 an eccentric nucleus may be observed (see cut, page 16). 
 
16 
 
 Pus : Pus corpuscles in milk appear as pale globular bodies of 
 varying size. They possess a slightly granulated surface, which 
 disappears on addition of acetic acid, while the corpuscles get con- 
 siderably enlarged. 
 
 Pus corpuscles and epithelial cells. 
 
 Epithelial cells are found in milk but rarely, and then, per- 
 haps, accidentally. 
 
 Lower oi'ganisnis: The presence oi fungi in milk can be de- 
 tected with the naked eye only when they are grouped together in 
 one place in dense masses. They have received considerable atten- 
 tion of late. It is, therefore, indicated to determine whether, in 
 the dairy industry, they are of equal importance as we know them 
 to be in other industries. The development of fungi is generally 
 a very complicated process, embracing a cyclus of the most hetero. 
 geneous shapes. Moreover, these various forms depend for their 
 
17 
 
 development on the nature of the substance upon which they 
 grow. The air contains, normally, fungi ; but it contains far more 
 in damp and badly-ventilated stables. It is, therefore, but natural 
 that milk should contain them also, since the air cannot be ex- 
 cluded. When milk, on standing, sours or decomposes, we find, 
 therefore, always fungi, whether the process is a normal or an ab- 
 normal one. It is not absolutely, but at least reasonably certain, 
 that these changes are produced by fermentation, from the fact 
 that Appert's milk-preserving process is successfully applied in 
 dairies. 
 
 The following species of fungi have been found in milk which 
 is undergoing decomposition : 
 
 1. Oidium lactis^ now known as mycoderma laciis, milk yeast. 
 
 2. Mucor racemosus Fres. 
 
 3. PeniciUium glaucum Link. 
 
 4. Dictyostelium mucoroides Bref. 
 
 "With these we always find bacteria and various species ot 
 vibrio, zoogloea and raonades. 
 
 Speefie Gravity. 
 
 Definition : Specific gravity is the figure which indicates the 
 relation of the weight of a body, as compared with the weight of 
 an equal volume of distilled water at the same temperature. The 
 specific gravity of milk, determined at 15° C, depends upon its 
 composition, and varies between certain limits. Albuminates, 
 milk sugar, and salts increase its specific gravity, fat diminishes it. 
 
 The difference in the specific gravit}' of milk, just after milk- 
 ing, or after standing for some time, or boiling, is, perhaps, due to 
 the air which dissolves in the milk during the milking, when it is 
 thus in thin layers exposed and thoroughly mixed into it. 
 
 The butter globules may be liquid or solid, according to their 
 temperature and composition, and the specific gravity of milk may 
 by this be influenced ; but how and to what extent this is done, 
 has not yet been investigated. 
 
 Apparatus for the determination of the specific gravity : 
 The specific gravity of milk is determined — 
 
 1. For scientific purposes, by weighing the milk in a flask of 
 known contents (pycnoraeter). 
 
18 
 
 2. For practical purposes, by the use of an areometer (lacto- 
 deusimeter). 
 
 Weighing in a flask : The flask used for tlie determination 
 of tlie specific gravity is of thin glass, and is closed with a care- 
 fully ground, solid glass stopper, or one consisting of a thermometer. 
 The latter are, for convenience sake, to be preferred. This flask 
 should hold from 30 c.c. to 50 c.c, and the edge of its neck should 
 not be laid outward and rounded, but cut off straight. To clean 
 these flasks after use, they should be rinsed with caustic soda solu- 
 tion, then with water and absolute alcohol, and finally with ether. 
 Cloth should be used, instead of paper, to dry and clean them ex- 
 ternally. 
 
 It must be avoided to touch the flask with the hands while it is 
 used, to prevent changes to temperature, which, by the consequent 
 expansion of the fluid, would lead to inaccurate results. The tem- 
 perature of fluids, the specific gravity of which is thus to be de- 
 termined, should not vary more than 2° from the temperature of 
 the air in the balance-room. Should it be warmer, it would hap- 
 pen, especially in the case of milk, that the fluid at the sides be- 
 comes colder and commences to contract, while in the interior, 
 around the mercury bulb of the thermometer, the fluid retains its 
 original temperature. It is necessary, therefore, to determine the 
 temperature of the room by another thermometer. The tempera- 
 ture exerts a considerable influence upon the results. Therefore, 
 to obtain exact readings, the bulb of the thermometer should remain 
 in the fluid for at least one or two minutes, and then be read to 
 0.1 degree. The specific gravity found is corrected by the use 
 of Kopp's tables. 
 
 YOLUMINA AND SPECIFIC GrAVITY OF WatER, ACCORDING TO 
 
 H. Kopp. 
 
 S/fc. Cr. of the Water 
 at 0° C. = I. 
 
 1.000000 
 
 1.000053 
 1.000092 
 1.000115 
 1.000123 
 1.000117 
 1.000097 
 
 TEMPERATURE. 
 Centigrade. Fahrenheit. 
 
 0. 32.0 
 
 Volume of the Water 
 
 at o° C. = I. 
 
 1.00000 
 
 1. 
 
 33.8 
 
 0.99995 
 
 2. 
 
 35.6 
 
 0.99991 
 
 3. 
 
 37.4 
 
 0.99989 
 
 4. 
 
 39.2 
 
 0.99988 
 
 5. 
 
 41.0 
 
 0.99988 
 
 6. 
 
 42.8 
 
 0.99990 
 
19 
 
 
 
 TABLE CONTINUED. 
 
 
 TEMPERATURE. 
 Centigrade. Fahj-enheit, 
 
 Volume of the Water 
 at o°C. = I. 
 
 spec. Gr. of the Water 
 at o° C. = 1. 
 
 7. 
 
 44.6 
 
 0.99994 
 
 1.0000G2 
 
 8. 
 
 46,4 
 
 0.99999 
 
 1.000014 
 
 9. 
 
 48.2 
 
 1.00005 
 
 0.999952 
 
 10. 
 
 50.0 
 
 1.00012 
 
 0.999876 
 
 11. 
 
 51.8 
 
 1.00021 
 
 0.999785 
 
 12. 
 
 53.6 
 
 1.00031 
 
 0.999686 
 
 13. 
 
 55.4 
 
 1.00045- 
 
 0.999572 
 
 14. 
 
 57.2 
 
 1.00056 
 
 0.999445 
 
 15. 
 
 59.0 
 
 . 1.00070 
 
 0.999306 
 
 16. 
 
 60.8 
 
 1.00085 
 
 0.999155 
 
 17. 
 
 62.6 
 
 1.00101 
 
 0.998989 
 
 18. 
 
 64.4 
 
 1.00118 
 
 0.998817 
 
 19. 
 
 66.2 
 
 1.00137 
 
 0.998631 
 
 20. , 
 
 68.0 
 
 1.00157 
 
 0.998435 
 
 21. 
 
 69.8 
 
 1.00178 
 
 0.998228 
 
 22. 
 
 71.6 
 
 1.00200 
 
 0.998010 
 
 23. 
 
 73.4 
 
 1.00223 
 
 0.997780 
 
 24. 
 
 75.2 
 
 1.00247 
 
 0.997541 
 
 25. 
 
 77.0 
 
 1.00271 
 
 9.997293 
 
 26. 
 
 78.8 
 
 1.00295 
 
 0.997035 
 
 27. 
 
 80.6 
 
 1.00319 
 
 0.996767 
 
 28. 
 
 82.4 
 
 1.00347 
 
 0.996489 
 
 29. 
 
 84.2 
 
 • 1.00376 
 
 0.996202 
 
 30. 
 
 86.0 
 
 1.00406 
 
 0.995908 
 
 Determination : The flask, after having been thoronghlj 
 cleaned, is dried at 100° C, and left to cool in the desiccator. It 
 is then weighed, and after that filled with water which has previ- 
 ously been freed from air by boiling, and been left to cool in a 
 covered flask. Care must be taken that no air bubbles adhere to 
 the glass. The stopper is then adjusted, and the outside carefully 
 dried. It is then re-weighed, and the temperature observed. The 
 contents of the flask, at a certain temperature, are thus deter- 
 mined. 
 
 After removing the water and drying, the bottle is filled with 
 the milk, which has first been well mixed, using throughout the 
 same precautions. If the temperature of water and milk are not 
 
the same, the observed weights must be corrected by the above 
 table in the following manner : 
 
 Found, weight of empty bottle 15.235 
 
 " " bottle -I- water at 18° C 46.327 
 
 Weight of water at 18° C 31.092 
 
 Weight of bottle f milk at 16° C 47.226 
 
 " " " empty 15.235 
 
 Weight of milk at 16° C 31.991 
 
 The water having been weighed at 18° C, we have to deter- 
 mine the quantity of water required to fill the flask at 16° C. The 
 respective specific gravities of water are : 
 
 At 18° C, 0.998817 ; at 16° C, 0.999155. 
 
 The weight of the water required to fill the flask at 16° C. is, 
 therefore, 
 
 0.998817: 31.092 = 0.999155 : X 
 X = 31.102 grs. 
 
 31.991 
 
 The specific gravity of the milk is, therefore, = 1.028. 
 
 31.102 
 This is the specific gravity of the milk at 16° C, compared with 
 water at 16° C. 
 
 Since the coefficients of expansion of milk and water differ cer- 
 tainly not considerably, we can also consider the specific gravity of 
 this milk to be =• 1.028 at 15° C, if compared Avith water of this 
 temperature. 
 
 If once the contents of the flask are known, it is unnecessary 
 to repeat the weighing with water for each determination. It is 
 only necessary, from time to time, to examine the weight of the 
 flask, to ascertain whether it has not lost in weight by the removal 
 of, small splinters of glass or by scratches. 
 
 Lactodensirneter : For ordinary determinations an areometer 
 or lactodensimeter may be emplo^^ed to ascertain the specific 
 gravity. Quevenne's lactodensimeter is the most exact, and the 
 one most generally used. For description and use of this instru- 
 ment, we refer to the chapter treating on " Milk inspection." 
 
21 
 
 Chemical Analysis of Milk. 
 
 GENERAL RULES. 
 
 For the examination of milk one must be enabled to coitimence 
 the examination at once, and to carry it thi'ou^h without loss of 
 time. It is, therefore, absolutely necessai-y that the laboratory be 
 well supplied with all the apparatus mentioned at the end of this 
 book, in such quantity that no time is lost by preparations of any 
 kind. 
 
 The first process taken in hand consists in the coagulation of 
 the milk. When this is in progress the determination of the 
 solids and salts is commenced. After the filtration from the co- 
 agulated albuminates is finished, and while the milk is drying on 
 the water bath, the physical properties and the reaction of the milk 
 are determined. 
 
 Milk should be thoroughly mixed before samples for the various 
 determinations are removed. For exact analyses it is also necessary 
 not only to measnre the milk, but to verify and correct the figures 
 obtained by measurement by actual weighing in a covered vessel. 
 
 A careful and exact record of all data concerning the analysis 
 is indispensable. Measures should be given in cubic centimeters 
 and weights in grammes ; and for the measurement of the temper- 
 ature, the Celsius or Centigrade thermometer should be employed. 
 
 In case that the temperature has been observed on a Fahren- 
 heit thermometer, the corresponding degrees of the Celsius ther- 
 mometer may be found by the table given on page 18. For higher 
 temperatures than those given in this table, the corresponding 
 temperature on the Centigrade thermometer may be found by 
 deducting 32 from the degrees read, dividing the rest by 9, and 
 multiplying by 5. For instance : 
 
 (185—32) X 5 
 
 185° F = = 85° C. 
 
 9 
 
 and, vice mrsa^ we may convert Celsius degrees into degrees 
 Fahrenheit hy the following equation : 
 
 85 X 9 
 85° C. = + 32 = 185° F. 
 
Reaction of Milk. 
 
 "While former investigators assign to milk always either an acid, 
 alkaline or neutral reaction, later investigations have proved its re- 
 action to be amphotere. Soxhlet states that a milk of only acid or 
 alkaline reaction is an impossibility, since basic, neutral or acid 
 phosphates never show a neutral reaction. To add to milk alkali 
 until no acid reaction can be observed, would produce a milk of 
 strongly alkaline reaction. The opposite takes place when, with 
 the aid of acids, we desire to extinguish the alkaline reaction. 
 
 This amphotere reaction can, however, only be proved by the 
 use of specially prepared litmus paper (see Fresenius, Qual. Analy- 
 sis), or better yet, with Liebreich's litmus plaster plates {Berl. Ber.^ 
 I, 48). 
 
 To test for the reaction, one drop of milk is brought by means 
 of a glass rod upon the test paper (blue or red). If the red is 
 turned blue, we have an alkaline reaction, or if the blue be turned 
 red, an acid reaction. Xo change on either would prove a neutral 
 reaction. 
 
 The reaction most generally observed and reported is the neutral 
 reaction. 
 
 Determination of Water and Solids. 
 
 The solids are determined as follows : 
 
 10 CO. milk are carefully weighed in a dry, counterpoised 
 and covered platinum dish. To this absolute alcohol sufficient for 
 coagulation is added. The coagulated mass is then dried on a 
 water bath ; and, before it has lost all its moisture, it is, by means 
 of a spatule, carefully spread over the sides of the dish to increase 
 its surface, whereby drying is greatly facilitated. It is then 
 brought into an air bath, and dried to constant weight at from 100 
 to 110° C. To this end the weighings are repeated every hour^ 
 the dish, with cover, being allowed to cool in a desiccator before 
 each weighing. We thus have : 
 
 Platinum dish + cover + dry solids, 
 Minus platinum dish cover, 
 
 Leaves dry solids. 
 
23 
 
 Difference between milk taken and dry solids = water + vola- 
 tile substances. 
 
 Good milk should have 12.5 per cent, of solids. 
 
 Determination of ashes and phosphoric acid : The residue 
 from the determination of solids is then heated first over a small 
 flame, and finally at a dull-red heat, until complete incineration is 
 effected. It is advisable to incinerate, if possible, in a muffle. 
 The dish is then covered, and allowed to cool in the desiccator, and 
 finally weighed. 
 
 Platinum dish + cover -{- ashes, 
 Less platinum dish + cover. 
 
 Leaves ashes. 
 
 The ashes of milk vary from 0.5 to 0.75 per cent. More than 
 0.75 per cent, found in an analysis would indicate the addition of 
 alkalies, which are frequently used during the hot season in the larger 
 cities to retard souring. The reaction of such ashes is then alkaline, 
 and will show effervescence on the addition of acid. The ashes of 
 normal milk show a neutral reaction, and do not effervesce with 
 acids. 
 
 The phosphoric acid is easily and accurately determined by 
 the following method : In the manner stated above, 50 c.c. milk are 
 dried and incinerated. The salts are then dissolved with some 
 hydrochloric acid, and the solution is brought to 20 c.c. To 10 
 c.c. of the cold solution, ammonia or caustic soda is added until 
 the reaction of the fluid has become alkaline. This is then acidi- 
 fied with acetic acid. The solution thus treated contains but 
 little acetates, which would interfere with the delicacy of the end 
 reaction of ferrocyanide of potassium and uranium. To this solu- 
 tion a standardized solution of uranium is added. When the pre- 
 cipitate ceases to increase, the whole is boiled for a few minutes, 
 and one drop of the clear supernatant liquid is brought on a porce- 
 lain plate, and tested with a solution of ferrocyanide of potas- 
 sium. A brown coloration indicates the presence of an excess of 
 uranium solution, which, however,, may disappear again on con- 
 tinued boiling. The addition of uranium solution is continued 
 until the reaction remains. It is of advantage to make two titra- 
 tions at a time, using in one 0.5 c.c, between the tests, and in the 
 other, 0.1 c.c. 
 
24 
 
 The uranium solution is made of such strength that 1 c.c. = 
 0.005 gr. phosphoric anhydride. As regards the composition of 
 milk ashes, we refer to page 8, 
 
 For a complete analysis of the ashes, not less than 500 c.c. of 
 milk should be taken. For the method of analysis to be pursued, 
 we refer to Fresenius, Quantitative Analysis. 
 
 Coagu4ation and Determination of Albu- 
 minates and Fats. 
 
 In the method until now commonly used, the coagulation was 
 effected by acetic acid or carbonic anhydride. This method orig- 
 inates with Hoppe-Seyler, but gives inaccurate results, as has been 
 proved by the investigations of Liebermann, Manetti, Musso, 
 V. Nencki, and the author (see Kritik der Verscliiedenen Methoden 
 zur Bestimmung der Albuminate und Fette, Fresenius' Zeitschrift, 
 1880, and Petersen's Forschungen, 1879, 7, 301. 
 
 A very reliable and quick method is Ritthausen's, who proposes 
 to effect the precipitation of the albuminates and fats by means of 
 sulphate of copper solution. From a neutral or slightly acid solu- 
 tion, the coagulation is easily effected in the cold. The accuracy 
 of the method has been verified by a long series of examinations 
 of milk in which it has been employed. 
 
 Ritthausen proposes to dissolve 63.5 grs. pure sulphate of cop- 
 per in crystals to 1 liter. 10 c.c. of this solution contain 0.2 gr. 
 CuO. A second solution contains 60 grs. caustic potash in 1 liter 
 of water. Its specific gravity is 1.048. Author uses the same 
 solutions, but has modified Ritthausen's method by using a smaller 
 quantity of sulphate of copper. 
 
 The coagulation is carried out as follows : 10 c.c. milk are 
 weighed in a beaker covered with a watch-glass, and then diluted 
 with 100 c.c. water. After mixing well, the solution of sulphate 
 of copper is gradually added until the precipitate settles well, 
 while the liquid becomes perfectly clear. For this 2.5 to 3 c.c. of 
 copper solution are required, while Ritthausen uses 5 c.c. 
 
 Then potash solution is added to decompose the excessive 
 quantity of cupric sulphate. For this, one-half the volume of the 
 copper solution is required. The coagulated albumen enclosing 
 
25 
 
 the fat globules settles quickly, leaving the fluid perfectly clear. 
 The fluid is decanted through a filter which had previously been 
 dried at 110° C, and weighed between two watch-glasses. The 
 precipitate is then stirred up with 100 c.c. of water. After al- 
 lowing to settle, the water is likewise decanted through the filter, 
 and finally the precipitate is brought upon it. The beaker is then 
 cleaned by means of a rubber washer, and washed with water until 
 everything is transferred to the filter. Thus, about 240 c.c. of 
 filtrate are obtained, which are diluted to make it exactly 250 c.c 
 This filtrate is used for the determination of milk sugar. 
 
 The beaker contains always some fat, which must be added to 
 the fat obtained from the albumen precipitate, and is, therefore, 
 set aside until this operation is in order. The copper casein pre- 
 cipitate, containing all the albuminates and the fat of the milk, ex- 
 cepting that portion which was left on the beaker, is then, by 
 means of a small spatule, well distributed over the whole surface 
 of the filter, which had been previously transferred to a large watch- 
 glass. This aids the evaporation of the water considerably, and 
 becomes necessary from the fact that the application of higher 
 temperatures must jbe avoided. To effect drying, the filter may 
 be exposed to the sun, or the watch-glass may be placed where it is 
 exposed to a moderate temperature. From time to time the pre- 
 cipitate is again worked with the spatule, care being taken that 
 the filter is not injured. After some time the residue becomes a 
 finely divided dry powder, which can easily be collected in the 
 point of the filter, and from which the fat can be extracted. 
 
 Determination of fat : The ordinary open extraction of the 
 fat, consisting in the washing of the precipitate with warm ether 
 on an open funnel, until the precipitate is exhausted, has disadvan- 
 tages, resulting not only in a loss of fat by effervescence, but also 
 in the waste of a considerable quantity of ether. Far more eco- 
 nomical is the use of a closed apparatus for the extraction of fat. 
 
26 
 
 The apparatus constructed for this purpose bj the author is ar- 
 ranged as follows : 
 
 ^ is a flask of from 5 to 6 centimeters in width and 6 to 7 cen- 
 timeters in height. On this stands the funnel B^ the neck of the 
 funnel being carefully adjusted into the neck of the flask by 
 grinding. The funnel is from 6 to 8 centimeters wide and from 
 8 to 10 centimeters high. The upper edges, d d, of the funnel 
 are bent outward to allow of an easy adjustment of the cork, and 
 the lower aperture must remain of full width, and should not 
 be narrowed down, as is often done.* The filter containing the 
 precipitate is then loosely inserted into the funnel, which then is 
 adjusted to the previously weighed 'flask. The filter is now washed 
 with some absolute alcohol to remove the last traces of moisture 
 from the precipitate. The beaker, which had been used for the 
 coagulation, and which had been set aside, is now freed from fat 
 by repeatedly washing it with small quantities of ether, which are 
 poured upon the filter. This is continued until the flask is filled 
 to about one-half with ether. 
 
 The apjDaratus is then, by means of a good cork, free from 
 poresjf connected with an inverted Liebig's cooler, and put upon a 
 
 * An ordinary wide-necked flask, to which the funnel is attached by means 
 of a good cork, may serve in the place of the complete apparatus, as described. 
 
 t Corks may be prepared by covering the outer surface with silicate of 
 soda. 
 
27 
 
 sand bath, whicli is cautiously heated by means of a Bunsen 
 burner. The heat must be so regulated that the filter swims con- 
 tinually to one-half its height in condensed ether, and the cooling 
 must be sufficient to prevent the escape of ether. Thus the com- 
 plete extraction of the fat may be effected in about one hour. The 
 funnel is then removed, and the flask is connected with a cooler, 
 and the ether, which contains alcohol, recovered by distillation at 
 very low temperature. The flask is then put in an air bath, laying 
 it on its side, and dried for one or two hours at a temperature of 
 100 to 105° C. After cooling in a desiccator, it is weighed. 
 
 The increase of weight corresponds to the amount of fat con- 
 tained in the quantity of milk taken for analysis. The residue in 
 the filter is then dried for two hours at from 110 to 120° C, and 
 weighed between two watch-glasses. After this it is transferred 
 to a porcelain or platinum crucible, and incinerated. 
 
 Weight of filter + dry coagulum. 
 Minus weight of filter + ashes. 
 
 Leaves albuminous substance. 
 
 The nitrogen determination in this substance, if required, must 
 be made by Dumas' method, on account of the presence of cupric 
 oxide, which, in an attempt to use Will Yarrentrape's method, 
 would cause a loss by the partial destruction of the ammonia. The 
 determination of albuminates by simple incineration, is, however, 
 sufficiently exact. 
 
 For a description of Dumas' method for the determination of 
 nitrogen, we refer to Fresenius, Quantitative Analysis. 
 
 A separation of so-called albumen and casein is wrong ; a de. 
 termination of the sum of all albuminous substances is, generally^ 
 all that is required, if the investigation is not to go into such de- 
 tails as those mentioned on pages 6 and 7. 
 
 Determination of Milk Sugar. 
 
 The sugar of milk is determined in the 250 c.c. fluid which 
 have been filtered from the coagulum obtained by the addition of 
 cupric sulphate to milk. The method adopted by the author con- 
 sists in the titration by means of Fehling's solution. 
 
28 
 
 It is well here to mention that sugar of tnilk is the only sugar 
 which can accurately be determined by tlie use of this method, 
 provided the original plan of manipulation is adliered to. 
 
 The author proposes to prepare two separate solutions to avoid 
 the changes which Fehling's solution always undergoes. To this 
 end he prepares a standard copper solution, containing in 1 liter at 
 15° C. 34.64 cupric sulphate, purified by repeated crystallizations, 
 grinding, and drying between filter papers. The second solution 
 is prepared by dissolving 173 grs. of rochelle salts in 350 c.c. of 
 water, and boiling. After cooling, 600 c.c. of sodium hydrate solu- 
 tion (sodium hydrate purified by crj-stallization from alcohol) of 1.12 
 specific gravity, which had likewise been heated to boiling, are 
 added. The mixture is finally brought to 1 liter at 15° C. 
 
 These two solutions are kept separate in a number of small 
 well-corked bottles, and are only mixed when used. 
 
 For the titration of the sugar, the following plan has been 
 adopted : 5 c.c. of each of these solutions are brought into a por- 
 celain dish, with 20 c.c. of water, and heated to boiling. The sugar 
 solution is then gradually added from a burette, care being taken 
 that the solution is kept boiling constantly. 
 
 Evaporated water should, from time to time, be replaced by 
 the addition of distilled water. The formation of dry crusts on 
 any part of the dish must be prevented. They are likely to get 
 overheated, and thus may give rise to the formation of products 
 which also reduce copper solution. The titration shonld be re- 
 peated at least once, and must be completed within five to ten 
 minutes. The process is at an end when all the copper is thrown 
 down as red cuprous oxide, which is best determined by the com- 
 plete disappearance of the blue color in the liquid. To observe 
 this better, the dish is slightly inclined, so as to enable one to ex- 
 amine the color against a white background. In doubtful cases, a 
 trace of the fluid is filtered through a very small filter, acidified 
 and tested with potassium ferrocyanide. A red color indicates the 
 presence of copper, and a few more drops of the sugar solution 
 are added, the boiling being continued until the precipitation of 
 the copper has been completed. Care should also be exercised that 
 no sugar remains in the fluid. If, therefore, no copper reaction 
 ensues, we must always test for sugar in a separate portion by the 
 addition of copper solution, and boiling. 
 
29 
 
 It is to be observed yet, that the decolorized sohition, on stand- 
 ing over the cuprous oxide, absorbs oxygen from the air, and be- 
 comes again blue. For this reason each tritration must be carried 
 to an end in the shortest time, and a subsequent coloration is not 
 to be taken into account. We, therefore, determine the exact 
 quantity by two to three titrations. The first titration is only used 
 to determine the i-educing qualities roughly. 
 
 1 c.c. Fehling's solution = 0.00676 grs. milk sugar. 
 
 It is not advisable, as some propose, to take a drop of the fluid 
 out by means of a glass rod, and to test this on a porcelain plate 
 for copper, as described above. Finely divided cuprous oxide re- 
 mains frequently for a long time suspended in the fluid, and the 
 least trace of it in the fluid is apt to deceive. 
 
 The calculation is as follows : 
 
 Provided we used 18.2 c.c. of the sugar solution to reduce 5 c.c 
 copper solution, we have : • 
 
 18.2 : 250 = 0.0338 : X 
 X = 0.464 milk sugar. 
 
 Occasionally the sugar of milk is determined by difference. 
 
 According to the method of Soxhlet, 25 c.c. milk are diluted 
 with 400 c.c. water, and coagulated by means of a solution of sul- 
 phate of copper; the precipitate is filtered off, and the fluid is 
 brought to 500 c.c. 
 
 100 c.c. of this solution are then transferred to a beaker, and, 
 after adding 50 c.c. of Fehling's solution, are boiled over double 
 wire netting, while the glass is kept covered to prevent loss. After 
 six minutes' boiling, the sub-oxide of copper is collected on an 
 asbestos filter, dried, and reduced by heating in a current of hydro- 
 gen gas. The method is said to give quick (?) and accurate re- 
 sults. According to Soxhlet's investigations, 
 
 mgrs. of copper weighed correspond to mgrs. milk sugar : 
 
 393.7 300 
 363.6 275 
 333.0 250 
 
 300.8 225 
 269.6 200 
 237.5 175 
 204.0 150 
 171.4 125 
 138.3 100 
 
80 
 
 ABNORMAL COWS' MILK. 
 
 Abnormal cows' milk is not merely an adulterated milk, but 
 all milk which is not fit to be used as food without detriment to 
 the interest of the consumer. 
 
 Colostrum Milk. 
 
 The colostrum is the first nourishment for the young animal, 
 and, as such, of considerable importance ; but it is not suited for 
 dairy use. All dairy societies, for this reason, prohibit its sale. 
 Condensed milk factories refuse the milk until the sixth day after 
 calving, while in cheeseries they accept it only on the eighth day, 
 since colostrum is said to interfere with the curdling and the sub- 
 sequent process of ripening of the cheese. 
 
 Eiigling has made very thorough investigations regarding this 
 milk. He says : " The first three to four liters of the beastings milked 
 " after calving, are a yellowish-white mucilaginous fluid, which is 
 " frequently colored by blood, exhibiting a reddish-brown tint. It 
 " possesses a peculiar odor, and has, at 15° C, a specific gravity of 
 " from 1,06 to 1.08, 
 
 " The cream rises very slowly ; but, after long standing, where- 
 " by a skin of dry albuminates forms on the surface, from 50 to 75 
 " per cent,, by volume, of cream is obtained. The boundary be- 
 " tween milk and cream is not well marked. 
 
 " Colostrum is, on heating, converted into a solid cake. It pos- 
 " sesses originally an acid reaction, and keeps well, especially after 
 " a dry albumen skin has formed on its surface. It then appears un- 
 " changed, even after two weeks' standing. The casein, on curd- 
 " hng, developes a gas, and between the heavy flocks remains a red- 
 " dish-colored, opalescent serum, which bears great similarity to 
 " blood serum. The products obtained after this first milking as- 
 " sume gradually the character of cows' milk, until, after four days, 
 " the secretion of the glands shows all the properties of normal 
 " milk." 
 
 The change from colostrum to milk which may be used for in- 
 dustrial purposes, is, therefore, effected in a comparatively short 
 
31 
 
 time. It is slower with younger animals and such which are of 
 inferior development, as far as production of milk is concerned. 
 Good milking cows will generally on the third or fourth day 
 after calving, produce milk which can be boiled without sho-wing 
 any coagulation of albuminous matter ; while young animals will 
 furnish, even on the sixth and seventh day, a milk which will 
 show partial coagulation on boiling, and in w^hich colostrum cor- 
 puscles can be found with the aid of the microscope. 
 
 Beside blood, albumen, casein, fat, and ashes, we find the fol- 
 lowing substances as normal constituents of colostrum : sugar, 
 globuline, nucleine, urea, lecithine, and cholesterine. The pres- 
 ence of milk sugar has, as yet, not with certainty been demon- 
 strated. Eugling found the colostrum of twenty-tM'o cows, of the 
 ages from three to thirteen years, composed as follows : 
 
 Specific gravity 1.058 1.079 
 
 Ashes 1.180 2.310 
 
 Fat 1.880 4.680 
 
 Albuminates 11.180 20.210 
 
 Casein 2.650 7.140 
 
 Sugar 1.340 2.830 
 
 Colostrum milk is especially characterized by comparatively 
 large (0.005 to 0.025 m.m. diameter) granulated corpuscles. Aside 
 of these, fragments in various degrees of dissolution are found, 
 which frequently consist only of conglomerates of fat globules. 
 Bunches of cells from the lactiferous ducts, generally larger than 
 the colostrum corpuscles, are also occasionally met with (see fig., 
 page 16). 
 
 Poisoned Milk. 
 
 Metallic poisons: Milk may occasionally contain poisonous 
 metallic substances. These are derived either from sour food 
 kept in metallic vessels and consumed by the cow, or may be im- 
 parted to souring milk Avhich is kept in metallic vessels. (Taylor, 
 On Poison<i, p. 412.) The acids which are formed during souring 
 dissolve the oxides of copper, lead and zinc easily. It is said that 
 zinc vessels are used in some localities to delay the souring. 
 
 Examinations for Metallic Poisons : If the presence of 
 large quantities of metallic substances is suspected, the examina- 
 tion may be carried on in the following manner : 
 
32 
 
 From 50 to 100 c.c. of milk are precipitated with a few drops 
 of muriatic acid. After heating to boiling, the solution is filtered 
 from the precipitate, and the latter washed. The solution is then 
 evaporated to about 25 c.c, and again filtered to remove some 
 albumen and fat, which have become insoluble during the concen- 
 tration of the liquid. The concentration of the fluid is then con- 
 tinued until about 10 c.c. remain. These are distributed into 
 three test tubes, one being used for the determination of the 
 presence of zinc, another for copper, and the last for lead. 
 
 The presence of zinc is determined by means of sulphuretted 
 hydrogen passed through the almost neutralized solution. A 
 white precipitate would indicate the presence of zinc. Frequently 
 sulphur is precipitated, which, however, on heating on platinum 
 foil, burns without leaving a residue. The precipitate is there- 
 fore to be more closely examined. The hydrochloric solution 
 is made alkaline with ammonia, and sulphide of ammonia added, 
 when a white flocculent precipitate will be formed in the presence 
 of zinc. In case that only small quantities of zinc are present, 
 white turbidity ensues, and the precipitate becomes flocculent only 
 after long standing. 
 
 Lead is found in the hydrochloric solution by passing sulphu- 
 retted hydrogen through it, which produces a grayish-black pre- 
 cipitate. Chromate of potassium produces a yellow precipitate of 
 chromate of lead. 
 
 In the presence of coj?pe?', ammonia produces a dirty gray 
 color; potassium ferrocyanide a brownish-red color, or precipitate. 
 If some of the solution be brought on a clean piece of platinum 
 foil, and a clean knife be laid upon it, the latter becomes, in the 
 course of several hours, coated with a layer of red metallic copper 
 
 If these metals are present in only minute quantities, it is bet- 
 ter to destroy the albuminous matter by means of hydrochloric 
 acid and chlorate of potassium. The rest of the operation remains 
 the same. 
 
 Vegetable poisons: A case is on record wherein, in the City 
 of Rome, twenty-one persons were poisoned, in the year 1875, by 
 the milk of goats which had fed upon momordica, the fruits of 
 which are known to possess highly purgative properties. The pa- 
 tients recovered under medical treatment. 
 
83 
 
 Milk Containing Medicines. 
 
 Lewald's experiments have proved that medicinal substances 
 are rapidly conve^'^ed by the milk ; so, for instance, lead, arsenic, 
 oxide of zinc, sub-nitrate of bismuth, tincture of iodine and iron, 
 antimony, and mercury salts. 
 
 It has not been determined that milk suffers, under the influ- 
 ence of these substances, also a quantitative change ; but the expe- 
 rience of physicians has demonstrated that medicines administered 
 to the mother act, through the medium of milk, upon the suck- 
 ling. 
 
 Milk as the Cause of Disease. 
 
 It is a well-known fact that the use of milk, especially during 
 the hot season, when it undergoes changes quite rapidly, is attended 
 with some risk. Only later investigations have proved that milk 
 may also cause specific diseases. Milk has, in many cases, proved 
 to be the bearer of disease germs, and thus has caused the trans- 
 mission of contagious and infectious diseases. 
 
 Without reference to special cases, we will, to avoid prolixity, 
 only describe the diseases and their causes. 
 
 The milk may be the cause of infection : 
 
 Milk containing algae, obtained from 
 
 a cow which drank stagnant 
 
 water. According to Low. 
 
 1, By direct communication of the infection, derived mainly 
 from impure water, used either for watering cattle or as adulter^ 
 
84 
 
 ant of milk, or for cleansing the vessels used for keeping the 
 milk. John Ojle observed that cattle using stagnant water during 
 summer, became feverish. The microscoiDic examination of blood 
 and milk proved, in both, the presence of large numbers of micro- 
 scopical organisms, the same as were found in the water. The 
 milk was unfit for use, and normal milk mixed with a few drops 
 of the same water would undergo the same changes. 
 
 So may bacteria or spirilla, by reason of the use of impure water, 
 or other means, enter the milk, where they produce putrid fer- 
 mentation, which only in its latter stages is easily recognized by 
 odor and taste. These smallest organisms, variously magnified, are 
 represented in the cut given on page 33. 
 
 2. By absorption of the infectious material from the air of 
 the stable and dairy, or by contact with sick persons, 
 
 3. By abnormalities pre-existing in the milk, from the fact 
 that it is derived from sick animals. 
 
 Considering that a contagion finds in milk not only the condi- 
 tions for its preservation, but also for its propagation, we must 
 admit the possibility that, by the use of infected water for rinsing 
 milk vessels, the small quantity of water adhering to the sides of 
 the vessel may well suffice as a cause of disease. The same is true 
 for infection by air. 
 
 In England, many epidemics occurred which have been traced 
 to the milk as cause ; and, amongst these, impure water, employed 
 in the manner described, seems, in most cases, to have been the 
 originator. 
 
 Robinson mentions one case where milk, which was stored in 
 the sick-room of a typhus patient, caused an epidemic of typhus. 
 
 Bell relates an epidemic of scarlatina, which was caused 
 amongst the customers of a certain dealer whose cows had been 
 milked by scarlet fever convalescents. 
 
 A similar case is mentioned by Taylor. 
 
 Gerlach was the first who called attention to the dangers to 
 which consumers of milk are exposed, which is derived from cows 
 sick with tuberculosis. This chronic disease attacks mainly stable- 
 fed animals, which transmit this disease to hogs, sheep, calves and 
 rabbits fed upon their milk, 
 
 Stang mentions the case of a child which died with all symp- 
 toms of tuberculosis, and which had been infected by the use of 
 
35 
 
 the milk of a tuberculous cow. Experiments of Klebs have 
 proved that the contagion is not destroyed by the ordinary boiling 
 of the milk. Ballinger has lately corroborated these observations. 
 The milk of tuberculous animals is said to be thicker than 
 ordinary milk. The reaction is alkaline. The cream rises quickly. 
 Cream and milk are apt to putrefy in a short time. The milk is 
 not easily curdled by rennet or by heating. 
 
 Anthrax : Milk of cows sick with anthrax is said to become 
 stringy, and in this state it breaks easily. Infected milk should 
 not be used. It is said that cattle are predisposed to this disease 
 when fed on distillery swill or the refuse of starch and beet-sugar 
 factories. 
 
 Aphtha epizootica : Anaker says : " In some cases of aphtha 
 " epizootica (hoof and mouth disease), especially when the mucous 
 " membranes of the lacteal ducts are affected, or when the contents 
 " of the bladder find their way into the milk during the milking, 
 " the milk appears thicker, phlegmy, more yellow, lumpy, and 
 " blood-streaked. It emits a putrid odor, and possesses a repug- 
 " nant taste. Such milk will part, on standing, into a yellow se- 
 " rum, and a sediment which contains pus corpuscles and finely 
 " granulated masses in a state of dissolution. Such admixtures 
 " increase the specific gravity of such milk, while the percentage 
 " of fat, casein, and sugar are diminished. 
 
 " The amount of salts is increased. The reaction of the. milk 
 " is acid when the disease is at its height. It, therefore, curdles 
 " easy when heated to boiling. The cream yields often no butter • 
 " but butter made from such milk shows an unnatural yellow color. 
 " Whether such milk will prove injurious to the health of con- 
 " sumers, depends upon the nature of the abnormal constituents. 
 
 " Boiling does not always remedy the injurious properties of 
 " such milk. The use of such milk has been the cause of the fol- 
 " lowing symptoms : fever, blisters on the mouth and feet and the 
 
" hands, of the milkers, headache, and rheumatic pains affecting 
 " the whole body." 
 
 ]Milk of cows sick with the mouth and hoof disease. Acccording to G. T. Brown. 
 
 Aside of tlie easily recognized butter globules, it contains large, dark, 
 
 and granulated cells, vibrios connected to strings, and small 
 
 elliptic bodies, of which always two are connected 
 
 and show motion {bacteria). 
 
 The infection through milk is considered to be partially caused 
 by small blisters on the teats, the exudation of which becomes ad- 
 mixed to the milk. 
 
 C. Monin examined the milk of a cow sick with cattle plague, 
 and found its composition very variable : 
 
 Water and volatile 81.22 to 86.53 
 
 Salts 1.18 " 1.54 
 
 Albuminates 9.07 " 11.19 
 
 Fat 1.T7 " 3.75 
 
 Sugar of milk 0.46 " 1.85 
 
 Specific gravity 1.002 '' 1.05T 
 
 The milk in this affection is very rich in albuminates and salts, 
 but poor in fat and milk sugar. 
 
37 
 
 Influence of Food, etc. 
 
 The influence of food upon the milk of animals is a subject of 
 some importance, and should engage the attention of physicians, 
 since many waste products of important manufactures are at pres- 
 ent utilized for feeding purposes, either alone or in combination 
 with other food. 
 
 By means of such foods, substances may enter into the compo- 
 sition of milk, which make it totally unfit to serve as nourishment 
 for infants. 
 
 Much has been written and said to defend the use of such 
 waste products as food, yet nobody prefers such milk to milk from 
 cows which have been normally fed on good pasture. 
 
 Being constantly housed can, likewise, not be of advantage to 
 the well-being of an animal, especially if the stables are damp and 
 badly ventilated. 
 
 Potato distillery swill: Only a few fragmentary investiga- 
 tions have been made to determine the influence which is exerted 
 on the quality of the milk of cows M'hich are fed on potato distil- 
 lery swill. That the milk of such cows cannot be good may be 
 presumed, if we consider that the swill is not always fresh, nor 
 free from alcohol. 
 
 Ried found that such milk did not contain alcohol, but that it 
 is very poor in fat (1 to 1^ per cent.) The swill is poor in carbo- 
 hydrates, since the conversion of the starch into sugar, and finally 
 alcohol, is the object of the treatment. 
 
 Albuminates, acids and salts predominate ; hence, such milk is 
 richer in casein and salts, and comparatively poor in sugar and fat. 
 
 Clark found that the fat globules of such milk are small and 
 few, and that they are disposed to adhere together, forming aggre- 
 gates of considerable size. In two specimens, uncommon numbers 
 of epithelial cells were observed, some of which showed a peculiar 
 granulation, while others were colored. ' Some of these were \ery 
 small and enclosed butter globules, thus showing that they had 
 formed the coating of the lacteal ducts, and that they Lad loosened 
 before their inner structure had been completed. The deleterious 
 influence on the health of consumers, especially that of children, 
 which is caused by such milk, has been traced to the circumstance 
 
38 
 
 that SDch milk does not easily coagulate, and that the butter 
 globules are frequently united to large masses. Retarded coagula- 
 tion prevents easy digestion, and causes through an overloading of 
 the stomach, symptoms of irritation. (See Petersen, IRlchzeitung, 
 1877, No. 21, Ueber die schaedlichen Folgen der Branntwein- 
 schlempefuetterung fuer das Yieh.) 
 
 Brewers' grains : The investigations regarding the influence 
 upon the milk of cows fed with brewers' grains are not conclusive ; 
 yet we know that such milk is inferior, unless the grains are fed 
 quite fresh. 
 
 Milk in fermentation : E. Reichardt mentions a case of rapid 
 fermentation of mUh in a village in the neighborhood of Jena, 
 Germany. He looked upon the high temperature of the store-room 
 as the main cause for this rapid fermentation. Everything that 
 may induce fermentation should be excluded from the dairies as 
 well as stables. Fermentation might also be caused by feeding 
 cows on fermenting brewers' and distillers' grains and wash. Pus 
 has occasionally been found in milk ; it is derived from ulcers in the 
 interior of the udder. Other diseased conditions of the lacteal 
 glands may cause the presence of mucus in milk. 
 
 The facts related in the foregoing chapter are of great import- 
 ance, since they justify the so much needed sanitary inspection of 
 the milk as it reaches the markets, especially in larger cities ; but 
 such supervision should be extended to include the animals them- 
 selves, their food, water and housing. 
 
 Observations as to sickness amongst cows, inferior drinking water 
 for the cows, and untidy handling of the milk, may frequently 
 help to explain cases of sickness, especially amongst children. 
 
 Adulteration of Cows' Milk. 
 
 The adulteration of milk — in our climate, cows' milk — is in 
 larger cities an every day occurrence. The consequences of this 
 practice are the more to be deplored, as they mainly befall the in- 
 fants, who often depend upon milk as their sole nourishment. In 
 consequence of this, many children are committed to a sickly and 
 languishing existence, while many perish. It is for this reason 
 that city governments experienced the necessity to prevent these 
 practices, by an inspection of the article as it reaches the market. 
 
The adulterations are as follows : 
 
 1. Addition of water. 
 
 2. Partial removal of cream, skimming. 
 
 3. Skimming and watering. 
 
 4. Mixing of partially skimmed (evening or morning) milk 
 with whole milk. 
 
 5. Foreign substances to disguise the altered or unnatural ap- 
 pearance of milk. 
 
 Most cases of adulteration are to be classed under 1 to 4, those 
 under 5 being used to reestablish a normal appearance of adulter- 
 ated milk. 
 
 The following substances are known to be used for this purpose : 
 sugar, gum arabie, starch, dextrine, egg albumen, yolk of eggs, 
 earthy substances, alkalies and dyes, to blend the blue color of skim 
 milk. 
 
 Most of these adulterants exist more in books than that they 
 are actually met witli, for substances which can easily be found 
 by simple chemical reactions, or even by mechanical means, or 
 which may easily be discovered by taste or smell, are not those 
 which fraudulent dealers would be apt to choose. 
 
 Those who adulterate know well that chemists possess all the 
 means to detect such coarse adulteration ; they therefore confine 
 their operations mainly to watering, and the mixing of skim milk 
 with whole milk, in various proportions. 
 
 Watery milk: Watery milk of a bluish-white color, poor in 
 fats and solids, is generally derived from cows under inferior treat- 
 ment, or when fed with extraordinarily poor and watery food. A 
 measure for the value of such milk is its specific gravity. This is, 
 however, governed by the quantities in which the various constit- 
 uents are present, for while salts, albuminates and milk sugar tend 
 to increase the specific gravity, the fat tends to diminish it. 
 
 If whole milk be mixed with water, the specific gravity will be 
 reduced, and analysis will show an excess of water and, correspond- 
 ingly, a diminished quantity of solids. 
 
 if milk be more or less skimmed, the specific gravity is in- 
 creased. By means of the lactometer or lactodensi meter, dealers 
 are enabled to dilute it with water to such an extent, that the spe- 
 cific gravity reached is within the limits of the law. A determina- 
 
40 
 
 tion of the fat will shoM' whether this has been practised, as it will 
 also in the case of mixtures of skim milk and whole milk. 
 
 To determine whether an abnormally watery milk or a watered 
 milk is before us, we may use chemical or mechanical means. For 
 scientific investigations only the former are used, and must consist 
 in a complete quantitative analysis. For practical purposes, we can 
 confine ourselves to a determination of fat and total solids. 
 
 Physical examination: The physical examination of milk 
 consists mainly in the determination of. the specific gravity. The 
 microscoj/ical examination is not fit for quantitative results, but can 
 merely be used for the determination of abnormalities, as blood, 
 pus, and colostrum corpuscles, or solid adulterants. It cannot be 
 used to determine with certainty the adulteration with water, 
 though it is a fact, that watered milk contains the larger and smaller 
 fat globules in the same proportion as whole milk, though further 
 separated from one another. The want, or deficiency, of the larger 
 or medium size globules, would indicate skimming. 
 
 Conrad has shown how difficult it is to obtain a good sample on 
 a slide, representing really an average of the milk to be examined ; 
 the same milk well mixed furnishing, by all the care that can be 
 bestowed, samples which show differences as regards the number, 
 size and distribution of the fat globules. 
 
 The estimation of the number of fat globules in the field is also 
 quite arbitrary. 
 
 Later on, in the chapter entitled " Milk inspection," a method 
 for the determination of the fat will be described, which, if not 
 absolutely accurate, admits at least of safe deductions. The spe- 
 cific gravity of normal market milk (such which I'epresents the milk 
 of several cows mixed), which possesses an average composition as 
 follows : 
 
 Water and volatile substances 87.50 
 
 Salts 0.50 
 
 Fat 3.50 
 
 Albuminates 4.00 
 
 Sugar of milk 4.50 
 
 100.00 
 ranges, according to many thousand examinations, in different 
 countries, from 1.029 to 1.033. A milk, therefore, which contains 
 
41 
 
 more than 87.5 per cent, of water, and which has a lower or higher 
 specific grav-itj than 1.029 to 1.033, must be considered as inferior 
 or adulterated ; also when it contains less than 3 per cent, of fat, 
 and when it otherwise shows considerable deviations from the 
 figures given above. 
 
 Yet such a milk cannot be directly considered as adulterated, 
 unless the sources of the milk have been examined, and until it 
 has been clearly demonstrated that the milk produced by the cow 
 does not show the same deviations from the average, as the milk 
 offered for sale. 
 
 Sour milk : The sale of sour milk, i. e., such which will curdle 
 on heating, should be prevented. 
 
 It happens frequently, especially during the summer, that milk 
 curdles before the examination could be commenced. Schroeder 
 and Dietzsch have stated that a simple determination of the specific 
 gravity of the whey is sufficient to establish an adulteration by 
 water. The specific gravity of pure whey is 1.026, and a lower 
 specific gravity would indicate addition of water. It would be 
 exceedingly desirable and would greatly aid in the inspection of 
 milk, if this statement could be verified by investigations in other 
 localities. 
 
 The following substances are used as adulterants : 
 
 StarcJi and flours : Such admixtures thicken the milk; the 
 taste and flavor of flour is easily distinguished. Such milks form, 
 on standing, a pasty sediment. After boiling or curdling, the milk 
 appears thready. The addition of starch is proved either by means 
 of the microscope, or by testing the whey after filtration and con- 
 centration fo one-quarter its volume, with tincture of iodine, when 
 a blue color will ensue. 
 
 Dextrine : Milk containing dextrine has a sweetish taste ; the 
 concentrated whey with tincture of iodine, becomes light violet or 
 the color of red wine. 
 
 Gum arable : The presence of gum arabic is determined in 
 milk by coagulation with acetic acid, filtering and concentrating 
 the serum to one-fifth its volume. Absolute alcohol precipitates 
 the gum as a white flocculent mass resembling casein (may con- 
 tain albuminates). Chevalier and Lassaigne state that this precip- 
 itate presents a 'streaky appearance. 
 
42 
 
 Coloring matters : The use of colors for the coloring of butter 
 and cheese has become so common in dairies, that now we find 
 them occasionally used for the coloring of poor blue milk. They 
 may be detected in the following manner : 
 
 500 c.c. of milk are coagulated with acid, or better, by the addi- 
 tion of YO per cent, alcohol. 
 
 The liquid is then filtered oflE and evaporated to 50 c.c. Addi- 
 tion of soda or ammonia produces a dark brown color in the pres- 
 ence of turmeric. 
 
 Annato : A blue coloration on addition of concentrated sul- 
 phuric acid, would indicate the presence of annato. 
 
 Preservatives : To prevent the souring of milk during the hot 
 season, various substances have been recommended. The appli- 
 cation of these by producers and dealers should not be tolerated, 
 but should be left to the consumer's choice. 
 
 Producer and dealer should attend solely to cleanliness of treat- 
 ment and the cooling of the milk, which even during the summer 
 is suflBcient to allow the safe transportation of the milk for con- 
 siderable distances. To prevent souring, the use of carbonate or 
 bi-carbonate of soda or potash is tolerated in France and England. 
 
 To demonstrate their presence, 50 c.c. milk are coagulated with 
 70 per cent, alcohol. The fluid is filtered and evaporated to 
 dryness. The residue, on addition of hydrochloric acid, will 
 effervesce when these salts had been used. 
 
 Neither normal whey nor milk ashes contain alkaline carbonates. 
 
 For a qualitative and quantitative determination of the alkalies 
 in milk, at least 500 c.c. are required. In some cases, viilJc of lime 
 has been used as a means of preserving milk. The reaction of 
 such milk is alkaline. After coagulation with acetic acid, the 
 whey is evaporated to one-sixth of its volume, filtered, and tested 
 with sulphuric acid, which, in the case of lime having been used, 
 will produce a precipitate of gypsum. {Chalk has also been em- 
 ployed. Of about 300 samples examined by Editor for the Metro- 
 politan Board of Healtli, in New York, only one sample contained 
 chalk.) 
 
 Salicylic acid and salicylate of soda have, of late, been 
 recommended and used for the preservation of milk. To deter- 
 mine its presence, 100 c.c. of milk are coagulated by the addition 
 of 70 per cent, alcohol. The whey is filtered off, and evaporated to 
 
43 
 
 one-eighth its volume. It is again filtered, and then shaken with 
 ether. Perchloride of iron added to the ether solution, will produce 
 a violet color if salycilic acid is present. Schulz states that a solu- 
 tion of salicylic acid in water, with some cupric sulphate solution, 
 becomes a beautiful emerald green. This reaction is even more 
 brilliant when the sodium salt is used, and can be easil}'- recognized 
 when dissolved in the proportion of 1 : 2000 parts of water. Al- 
 cohol hastens the appearance of the color. Acids and ammonia 
 prevent the reaction. 
 
 Boric acid and borax being more easily soluble, more active 
 and cheaper than salicylic acid, are used quite frequently as preser- 
 vatives. To determine their presence, 50 c.c. of milk are coagulated 
 with some acetic acid, and the filtrate evaporated in a platinum 
 dish. The residue, after drying, is incinerated. The ashes are 
 then heated with some alcohol containing from 1 to 2 per cent, of 
 cone, sulphuric acid. When the alcohol is then lighted, it will 
 burn with a flame which appears green colored at the edges, if 
 boracic acid be present. II. Gilm proposes to use the following 
 method, which is said to have the advantage of not only pro- 
 ducing a greener flame, but one which appears uniformly colored. 
 The boric ether vapors produced by the boiling of boric acid, 
 concentrated sulphuric acid and alcohol, are passed through a 
 narrow tube into a wider tube standing in vertical position. The 
 mixture of air and vapors is then ignited at the upper end of the 
 wider tube. 
 
 Quack preservatives, at very high prices, are also in use, and 
 widely advertised. The most widely known are : 
 
 Aseptine, which is recommended for the preservation of milk and 
 cream, and which, according to Nettl and Fleck, consists merely of 
 finely pulverized boracic acid. 
 
 Glacialine is a mixture said to contain mainly boracic acid 
 and borax. 
 
44 
 
 MILK OP OTHER ANIMALS. 
 
 Goats' Milk. 
 
 Goats' milk is for the mountaineers what cows' milk is for the 
 inhabitants of the flat lands, for the reason that at places where 
 cows fail to obtain sufficient nourishment on pasture, or where this 
 could be obtained only under great danger, the goats will yet 
 thrive. The goat serves as the poor man's cow. The properties of 
 goats' milk are as follows : 
 
 Appearance: Color, white to yellowish. 
 Consistency : Generally thicker than cows' milk. 
 Odor: Specific and strong, especially developed in the milk of 
 goats which are kept in the stable. 
 Taste : Specific and sweetish. 
 
 Specific gravity: Varies considerably and averages from 1.028 
 to 1.036. 
 
 Chemical composition : It is richer than cows' milk, but vari- 
 able in composition. 
 
 Specific gravity average, 1.032. 
 
 "Water and volatile substances 85.0 - 87.00 
 
 Salts 0.5 - 0.75 
 
 Albuminates 4.0 - 6.00 
 
 Fat 3.5 - 5.00 
 
 Milk sugar 3.5 - 5.50 
 
 Sheeps' Milk. 
 
 Similar to the goats, the sheep are indigenous to mountainous 
 countries. It is in such countries only that sheep are kept, mainly 
 on account of the milk which they furnish ; so for instance, in the 
 Lozi^re, the Appenine and the Karpathian mountains. The many 
 points which mountain dairies and the dairies of the marshy flat 
 lands have in common, is also illustrated by the fact that sheep are 
 kept for their milk in Holland (Martiny). 
 
 Appearance : Color, yellowish-white. 
 
45 
 
 Consistency : It is richer than cows' or goats' milk ; the cream 
 rises slowlj, and the batter made from it is soft, greasy, and does 
 not keep well. 
 
 Odor and taste are similar to cows' milk. 
 Specific gravity: 1.034 to 1.042. 
 Chemical composition: 
 
 Water and volatile substances 80.0 - 85.00 
 
 Salts 0.5 - 1.25 
 
 Albuminates 4.0 - 6.50 
 
 Fat 4.0 - 7.00 
 
 Milk sugar 4.0 - 6.00 
 
 Asses' Milk. 
 
 Apart from the milks previously mentioned, asses' milk is often- 
 est used as a substitute for breast milk, especially in France. The 
 properties are : 
 
 Appearance: Color, white. 
 
 Consistency: More water than any of the milks previously 
 described. 
 
 Taste and odor are similar to cows' milk, but sweeter. 
 Specific gravity: 1.030 to 1.036. 
 Chemical composition : 
 
 "Water and volatile substances 89.00 - 92.0 
 
 Salts 0.25 - 0.5 
 
 Albuminates 1.50 - 3.0 
 
 Fat...- 1.00 - 2.5 
 
 Milk sugar 4.50- 6.0 
 
 Mares' Milk. 
 
 The keeping of mares for the purpose of utilizing their milk, is 
 at present practised only by some half cultivated races, and in the 
 kumyss establishments, where it is used for the manufacture of an 
 intoxicating drink, called kumyss. 
 
 Mares' milk possesses the following properties : 
 Appearance and consistency : Whitish and watery, like asses' 
 milk. 
 
46 
 
 Odor and taste : Similar to asses' milk, but sweeter on account 
 of a frequent preponderance of milk sugar. 
 
 Specific gravity: 1.031 to 1.036. 
 
 Chemical composition : 
 
 Water and volatile substances ... 90.00 - 92.5 
 
 Salts 0.25 - 0.5 
 
 Albuminates 1.50 - 1.0 
 
 Fat 0.50 - 1.5 
 
 Milk sugar 4.50 - 6.5 
 
 The description of other kinds of milk, apart of those already 
 mentioned, are of little value. The examination of such milks is 
 based upon the same principles as have been prescribed in the case 
 of cows' milk. 
 
47 
 
 CONDENSED AND PRESERVED MILKS, 
 WITH AND WITHOUT SUGAR. 
 
 Condensed Milk with Sugar. 
 
 Condensed milk and milk preserves have until lately been 
 prepared from cows' milk only. 
 
 Historical remarks : It is frequently, but erroneously, stated 
 that Gail Borden was the inventor of condensed milk. This is, 
 however, not so. The process of milk condensation is a European 
 and not an American invention, for long before Gail Borden were 
 condensed milks prepared by various processes known in France. 
 So that of Adolphe Anaclet Nalbec (1S26), Braconnot (1830), 
 Grimaud (1835), J. M. de Lignac (1847). Simultaneously this 
 subject received attention in Germany and England. Gail Borden's 
 patent dates from the year 1856. He can, therefore, not be called 
 the inventor of condensed milk ; but to him belongs the merit of 
 having first prepared condensed milk by a rational process and in 
 a practicable form. In later years this process was first employed 
 in the United States, but its use extended rapidly to other countries. 
 Switzerland, England, Germany and many other countries, possess 
 now establishments manufacturing this modern commodit}--, which, 
 apart of cheese and butter, is at present not only the most popular 
 milk-food, but one which finds more consumers from day to day. 
 
 The condensed milk containing sugar finds its waj^ into the 
 market, packed in tin boxes containing from 450 to 500 grms. of 
 the product. 
 
 Such condensed milk, evaporated, with the addition of more or 
 less sugar, in a vacuum pan, contains, if the process is properly 
 carried out, all the constituents of the milk unchanged as far as 
 their chemical and physical properties are concerned ; it differs 
 from cows' milk merely by having lost some of the water, and the 
 whole of the natural milk flavor. It is simply a prejudice that 
 Swiss condensed milk should, as regards richness, possess superior 
 qualities. Considerable stress is laid on the superior quality, 
 
48 
 
 especially as regards flavor, of the milk of cattle fed on Alp- 
 raountain pasture. 
 
 If we consider, however, that the establishments which manu- 
 facture condensed milk are not only situated in the valleys, but use 
 exclusively, as they do everywhere else, milk produced in the 
 valleys, the ridiculousness of the claims made for the purpose of 
 reclame are at once apparent. These claims are equalled only by 
 those proffered by the manufacturers of infants' milk-foods, "who 
 claim that their manufactures may fully compensate for the lack 
 of breast milk. Provided that only good cows' milk is used, and 
 that with an unvarying addition of sugar it is condensed to a 
 proper and equal degree, no good reason exists why condensed 
 milk produced in any other country- should not be equal to that 
 produced in Switzerland. 
 
 According to the season in which this milk is manufactui'ed, the 
 product differs in color. It is obtained whiter during the winter, 
 more yellow during the summer. Condensed to a proper degree, 
 it has the consistency of honey, and must, even after the boxes 
 have been opened, remain in good condition, without change. 
 Under such circumstances it should form a skin, consisting merely 
 of dried milk constituents and sugar crystals, while the milk 
 underneath should remain unchanged. 
 
 Sometimes such milk shows the consistency of cheese. This is 
 produced by carrying the condensation too far. It shows then, 
 frequently, odor and taste of rancid butter. Such milk is not 
 completely disintegrated by water. 
 
 Physical Analysis. 
 
 The condensed milk boxes are generally opened on that end 
 which is closed by one single tin sheet. For the purpose of ex- 
 amination, the boxes should be opened at the end where, through 
 a hole in the center, the milk had been filled in, and which then 
 had been closed by a separate cover, soldered air-tight to the box. 
 We do this to ascertain whether the soldering has been perfect 
 and has been performed without scorching the contents. To this 
 end the cover is removed by cutting it on the circumference for 
 about three-quarters. 
 
 The appearance of the milk is examined by removing some of 
 the contents by means of a knife or spatule, and by observing it 
 
49 
 
 against the light while it is allowed to run in a broad sheet back 
 into the box. 
 
 Any imperfections, as the existence of more or less granules, of 
 which good milk should contain but few, can thus be observed. 
 
 A good normal condensed milk should be of the consistency of 
 honey ; it should possess an agreeable flavor, and must be easily dis- 
 integrated, without the separation of a flocculent residue, by mixing 
 it with from four to five parts of water. Only products prepared 
 by deficient processes sJiow abnormalities. 
 
 The microscope reveals the ]Dresence of butter globules, crystals 
 of sugar, and groups of normal milk salt crystals. 
 
 Crystals of a moss-like structure are found in milk only when 
 the process of condensation has been carelessly performed. 
 
 The microscopical observation is greatly facilitated if the con- 
 densed milk is brought upon the slide with a drop of oil, which 
 will not affect the sugar crystals and salts. Cane sugar appears in 
 large monocHnic prisms ; milk sugar in four-sided tri-metric prisms ; 
 calcium lactate forms tufts of fine needles. 
 
 The specific gravity is determined in a flask of known weight 
 and contents, in the manner described above. 
 
 Chemical Examination. 
 
 For the determination of the solids and asJi, two to three 
 grms. of condensed milk are accurately weighed in a covered 
 platinum crucible, coagulated by means of absolute alcohol, and 
 treated as described on page 22. 
 
 Care must be taken that the sample is perfectly free from solder. 
 Its presence would not only produce inaccurate results, but would 
 destroy the platinum crucible when the solids are incinerated. 
 
 The albuminates and the fat are determined in two to three 
 grms. accurately weighed in a covered beaker ; 100 to 150 grms. 
 of water are then added, the whole mixed thoroughly and precipi- 
 tated with copper solution, as usual. From 1.5 to 2 c.c. of copper 
 solution, and O.Yo to 1 c.c. alkali solution are required. The 
 remaining part of the process of manipulation is the same as 
 previously described (see page 24). 
 
 The determination of the cane sugar and milk sugar is made in 
 such a manner that the latter is directly determined by means of 
 
50 
 
 Fehling's solution, while the former is calculated. This method 
 of determination b}' difference may well be accepted, considering 
 the fact, that the rest of the constituents is determined by very 
 accurate methods. 
 
 Well-preserved condensed milk of commerce varies in its com- 
 position according to the degree of concentration, the addition 
 of cane sugar, and the season in which it has been manufactured. 
 
 The composition of condensed milk from different establish- 
 ments varies as follows : 
 
 Water and volatile substances 20.0 - 30, 
 
 Salts 1.5 - 3. 
 
 Fat 8.0 - 12. 
 
 Albuminates 10.0 - 13. 
 
 Milk sugar 10.0 - 15. 
 
 Cane sugar 30.0 - 45. 
 
 Other Milk Preserves. 
 
 Condensed milk free from sugar, which is in general use in 
 many large cities of the United States, where it is sold by measure 
 from house to house, contains : 
 
 Water and volatile substances 46.5 - 55. 
 
 Salts 2.0 - 3. 
 
 Fat 13.0 - 20. 
 
 Albuminates 13.5 - 27. 
 
 Milk sugar l2.5 - 18. 
 
 The following specialties are also to be found in the market : 
 cacao milk, coffee milk, medicated milk (N. G.), malt milk (N. G.) 
 and salt milk, in which part of the cane sugar is replaced by salt. 
 This latter is said to be employed in the manufacture of oleo- 
 margarine. 
 
 Lately, also, an article has been brought into the market, which 
 is known in France as condensed Goudron m.iik, which is milk con- 
 densed with the addition of tar. 
 
 Condensed goats' milk, prepared by Gebr. Sigmond of Klaus- 
 enburg, Germany, has, according toaa analysis made by Godeffroy, 
 the following composition : 
 
61 
 
 Water and volatile substances 20.98 
 
 Salts 3.60 
 
 Fat 16.95 
 
 Albuminates 17.00 
 
 Milk sugar 15.72 
 
 Cane sugar 25.75 
 
 Preserved milk is generally prepared by Apperfs process, 
 which is known for the last forty years, and which consists mainly 
 in boiling the milk, to destroy ferments, and keeping it then in her- 
 metically sealed vessels. 
 
 Some methods of preservation by the use of chemicals are also 
 practically employed. 
 
 The report of an analyst on the analysis of preserved milk 
 should state : 
 
 1. Weight of can and milk, and weight of milk net, and 
 if possible, the price of the article. 
 
 2. Trade mark and remarks as concerns untruthful claims 
 made, etc. 
 
 3. Statement as regards the burning or scorching of the 
 milk, when packed. 
 
 4. Consistency, color and flavor. 
 
 5. Results of the physical examination, including that by 
 the microscope. 
 
 6. Eesults of the chemical analysis, arranged as given above. 
 
 Hygienic Demands. 
 
 The manufacturer should guarantee a certain chemical com- 
 position. Statements giving the average values in which the con- 
 stituents are present, should be given with each package. 
 
 As yet, condensed milk has never been found to have been 
 adulterated. 
 
WOMAN'S MILK. 
 
 Woman's milk differs from the milk of animals, especially 
 cows, not merely as regards the relative proportions in which the 
 various constituents are present. There exist in eome of these 
 constituents marked differences regarding their chemical proj)er- 
 ties. The albuminates of woman's milk, for instance, behave dif- 
 ferently towards precipitants. Woman's milk contains, according 
 to the latest investigations of P. Kadenhausen, no casein, but albu- 
 men, protalburaen and peptone, as they are found in the blood. 
 This is the cause of the alkaline reaction of woman's milk. The 
 milk loses its alkalinity, and shows then an amphotere reaction 
 only, when larger quantities of protalbumen occur. The butter 
 globules are in greater part free. With regard to these two points, 
 woman's milk differs considerably from cows' milk, which is very 
 rich in protalbumen. To these differences must be added, that 
 woman's milk sours but slowly on account of its great alkalinity, 
 and that the sugar predominates over the albumen. 
 
 The keeping qualities of woman's milk are such, that author 
 has kept such milk during the summer, and during the winter near 
 a stove, for from six to eight days before it curdled. 
 
 The appearance and composition of woman's milk differ con- 
 siderably. Figures stating the composition are necessarily aver- 
 ages from a large number of examinations. 
 
 The secretion of woman's milk and its composition are con- 
 siderably influenced by many circumstances, and more so than in 
 the case of animals. 
 
 L. Fleischmann (Klinik der Paediatrik, vol. 1.) mentions the 
 following : 
 
 1. Individual differences exert a certain but not a great influ- 
 ence upon the secretion and composition of the milk. Large breasts 
 by no means indicate that the milk secreted by them is of good qual- 
 ity, as has been clearly demonstrated by the milk examinations un- 
 tertaken by the author at the Bureau Central des Nourrices in Paris. 
 Lean but well-nourished wet nurses produce frequently a richer 
 
53 
 
 milk than fat nurses. Not much value should be attached to the 
 color of the hair. A good healthy appearance and a happy dispo- 
 sition are of far greater importance, 
 
 2. The age : Women of the age of 20 to 30 years furnish 
 generally the best milk. 
 
 3. The question of food, as regards its influence upon the 
 milk, should be considered from various points. Unaccustomed 
 but good food, taken for the purpose of exerting an influence upon 
 the secretion of milk, has rarely accomplished what has been ex- 
 pected, i. e., the secretion of better and richer milk. Different it is 
 with animals, where a change in the food, from vegetable to an- 
 imal diet, for instance, is at once followed by decided changes in 
 the composition of milk. 
 
 If, however, the consumption of food is below the normal, and 
 insufficient for the wants of infant and mother, either the one or 
 the other must suffer. 
 
 4. Menstruation : The influence of menstruation upon the se- 
 cretion of milk has long been overestimated. Even physicians con- 
 sider it their duty to forbid the continuance of nursing on its 
 recurrence. The examinations of Vernois and Becquerel have 
 proved that such milk is richer in salts, albuminates and fat, and is, 
 therefore, better. Only the quantity of the secretion is diminished. 
 
 5. Pregnancy : The continuance of nursing after the mother 
 has again become pregnant is accompanied by grave consequences. 
 ISTot only the mother and the child which she bears suffer, in conse- 
 quence of the greater demands made upon the mother, but also the 
 infant, whose supply of milk may be greatly diminished, if it does 
 not fail altogether. An additional danger to the nursing child has also 
 been found in the fact that such milk is apt to pass again through 
 the stage where colostrum is the natural secretion (Bouchut). 
 According to Davis' examinations, the solids which the milk con- 
 tains are, with progressing pregnancy, gradually diminished, es- 
 pecially so the albuminates, fat and sugar. 
 
 6. T/ie milk in various periods after hirth is not equal in its 
 composition. The first milk obtained at any one time from the 
 breasts is generally thinner, while the last is the richest. A few 
 days after birth the breasts yield colostrum, containing as yet gran- 
 ulated corpuscles, mucus and groups of butter globules. The 
 
54 
 
 colostrum acts as a purgative. After the eighth day the milk ap- 
 pears normal to the naked eye, though it may contain a few colos- 
 trum corpuscles. 
 
 Y. Sic/cness increases, in all cases, the milk solids, especially so 
 in cases of chronic disease. 
 
 8. The influence of all kinds of psychic emotion upon the 
 secretion of milk is well recognized. 
 
 9. The quality of the milk depends also on the number of 
 children which the mother has borne, as also on the age of the 
 previously horn child, and the surroundings and circumstances of 
 the mother. The milk from each of the two breasts differs, also. 
 
 All these circumstances must be considered and stated, if the 
 examinations make claim to scientific accuracy. 
 
 10. Medicines taken by the mother may pass into the milk as 
 they pass into cows' milk. 
 
 Abnormalities in milk are either caused by the lack or pre- 
 ponderance of one or more constituents, or by the presence of 
 substances not found in normal milk. 
 
 Woman's milk has the following properties : 
 
 Smell : Hardly perceptible when from white women, but pe- 
 culiar, and similar to the exhalations of the skin, in the case of 
 women of the African race (Mott). 
 
 Taste : Sweeter than cows' milk , occasionally salty. 
 
 Color : Bluish-opaque. 
 
 Consistency : It is more watery than the milk of animals. 
 Author found the milk, a few days or weeks after birth, rather 
 rich in fat. The fat collects often in small globules on the sur- 
 face; they possess an intensely yellow color, and are of such size 
 that they may be seen with the naked eye. 
 
 Reaction : The reaction is, according to the latest investiga- 
 tions — which embraced the examination of one hundred and fifty 
 samples — alkaline, provided the milk was tested directly after it 
 had been obtained (Conrad, L. Fleischmann). 
 
 The specific gravity ranged in 130 observations from 1.025 to 
 1.039, at 15° C. (Conrad.) 
 
55 
 
 Taking the Sample. 
 
 The time when a sample of milk is taken is by no means un- 
 important, and, in the case of woman's milk, presents some diffi- 
 culties. Herbivora give their milk generally at stated periods ; in 
 the case of woman, however, it is different, and the taking of the 
 sample is more difficult. With the report on an exact analysis, 
 such data, giving the details with regard to the sampling, are in- 
 dispensable. 
 
 Conrad proposes that the sampling be done, if possible, by the 
 analyst himself, to prevent intentional or unintentional delusion. 
 The best time for this is from two to three hours after the last 
 nursing, when the breasts have filled again, and are ready for 
 another nursing. The w^hole of the milk is then drawn, either by 
 means of a breast pump, or by the use of forefinger and thumb, 
 when it is collected in a clean, dry beaker. This latter manipula- 
 tion can, with some practice, be conducted without causing the 
 least pain, and is preferable to the use of the breast pump, since it 
 brings the milk quicker, and because it furnishes better indications 
 regarding the quantity of milk, and also its quahty and consis- 
 tency. By observing if the .milk flows in thicker or thinner strains, 
 faluable hints regarding the explanation of certain irregularities 
 with reference to the nursing of the infant, and its digestion, may 
 be obtained. 
 
 Thus, from 30 to 50 or 100, and sometimes even 200 c.c, of 
 milk may be obtained. For really exact investigations, the milk 
 from both breasts should be drawn and intimately mixed before 
 the examination. 
 
 Physical Examination. 
 
 The specific gravity is determined for scientific purposes by 
 means of a bottle of known weight and contents. For ordinary 
 purposes, a lactodensimeter of Quevenne, of reduced size, may be 
 used (Conrad's). They allow the determination of the specific grav- 
 ity in from 30 to 40 c.c. of milk. The manipulation and calcula- 
 tion are the same as -will later be mentioned in the chapter treating 
 on "Milk inspection." For a better estimation of the quality of 
 woman's milk, a determination of the fat by means of the lacto- 
 butyrometer should be made. 
 
56 
 
 An apparatus for this and the determination of the specific grav- 
 ity, neatly packed in a case and ready for use in hospitals, has been 
 devised by Dr. F. Conrad, and its application been described by 
 him in a pamphlet entitled "Die Untersuchungen der Frauen- 
 milch fuer die Beduerfnisse der aerztlichen Praxis," Bern, 1880, J. 
 Dalp. 
 
 Microscopical Examination. 
 
 It must not be attempted to determine the quantity of fat in 
 woman's milk by means of the microscope. The difficulties which 
 present themselves here are even greater than in the case of cows' 
 milk. 
 
 The butter globules are scarce on the second day after delivery, 
 while the granulated colostrum corpuscles predominate. Gradually 
 the latter disappear while the former increase, until at about the 
 sixth to eighth day after birth, they fill the whole field of vision 
 quite densely. They appear of nearly uniform size, are round and 
 highly refracting. The nourishing qualities of a milk depend on 
 the quantity of fat globules, since milk sugar and albuminates in- 
 crease in proportion. The presence and preponderance of very large 
 butter globules indicates richness in fat. Such milk is more diffi- 
 cult to digest. Milk which contains badly-formed globules is lack- 
 ing in nourishing quahties. 
 
 Woman's Milk. — The butter globules at the right upper part of 
 the drawing appear irregularly shaped, produced 
 by the action of acetic acid upon them. 
 
57 
 
 Large globules are generally observed after a protracted period 
 of nursing, and if the mother is advanced in age, an increase of 
 the size of the globules has also been observed, and is then accom- 
 panied bj the appearance of colostrum corpuscles at the period of 
 menstruation, as also in cases of sickness accompanied by fever. 
 
 Yery small globules predominate in the milk of insufficiently 
 nourished or sick mothers. The children show then frequently 
 symptoms indicating an insufficiency of food, as rachitis, atrophia, 
 anaemia, leucaemia, etc. 
 
 Colostrum corpuscles may often appear in the milk, and betraj', 
 generally, sickness of the mother (feverish emotion, menstruation, 
 etc.) If present in large numbers, they cause dyspepsia. Their 
 occasional appearance is of no consequence. 
 
 Woman's Colostrum. 
 
 Blood Corpuscles are found in cases of inflammation of the 
 breasts, excoriation, ulceration, etc. 
 
 Pus is found in cases of abscess of the parenchym of the 
 glands. 
 
 Chemical Analysis. 
 
 The reaction is determined in such manner as has been de- 
 scribed in cows' milk. 
 
 The methods of coagulation of albuminates and fat, as de- 
 scribed by Hoppe-Seyler, Tolmatschoff, Brunner, Schukoffsky, 
 
58 
 
 Christena and others, are well known and have been sufficiently 
 discussed, that we may consider that our readers are sufficiently 
 acquainted with their drawbacks, consisting partly in very tedious 
 operations, partly in unreliable results. (See Fresenius' Zeit- 
 schrift, 18S0; Petersen's i^<??•5<?/iw;^^^;^, 1879; Gerber und Raden- 
 hausen's Vorschlaege zu einer einheitlichen Untersuchungsmethode 
 der Milch, Schweizer Wochenschrift f. Pharmacie, 1879.) The 
 method employed by the author is a modification of the one pro- 
 posed by Ritthausenfor cows' milk. The albuminates of woman's 
 milk differ from those found in other milks, especially, also, 
 in their behavior to precipitants. A few c.c. of cupric sulphate 
 solution precipitate the albuminates in 10 c.c. of cows' milk easily 
 and completely, while in woman's milk but a part of the albumi- 
 nates can thus be coagulated. By a modification of the process, 
 Jjowever, complete coagulation can be obtained. To this end 
 it is necessary to neutralize the acid in tlie sulphate almost or 
 completely. Thus a fine flocculent precipitate is formed, which 
 contains the fat and all the albuminates. 
 
 After a great many experiments the following method was 
 adopted : 
 
 5 c.c. of woman's milk are diluted with 100 c.c. of distilled 
 water, and after mixing well 3 c.c. (sometimes, perhaps more) of 
 cupric sulphate solution are added, and then at once 2.5 to 3 c.c. 
 of the alkali solution (strength of the respective solutions as 
 given in the article on cows' milk). A precipitate is produced 
 which sinks easily to the bottom of the beaker. For its further 
 treatment we refer to the detailed description given in the chapter 
 on the " Chemical analysis of cows' milk," p. 24:. 
 
 The determination of the solids and ashes is made in 10 c.c. 
 of accurately weighed woman's milk. The particulars for the ex- 
 amination of this milk do not differ from those described in the 
 chapter on the " Analysis of cows' milk," to which we refer. 
 
 The difference in the composition of the milk of white women 
 compared wdth that of women of the African race, has been 
 given by II. A. Mott, jr. According to his statement, the secretion 
 of the milk commences on the seventh or eighth day. The color 
 of this milk is yellowish-white, resembling cows' milk. It is richer 
 in solids than the milk of white women, and, on evaporation, 
 
69 
 
 shows a distinct odor. The colostrum is similar to that observed 
 with white women. 
 
 Albumi- Milk 
 
 Milk of while women. Water. Salts. Fat. nates. Sugar 
 
 Average of 14 Analyses (Tidy) 87.806 0.285 4.021 3.523 4.265 
 
 "89 " (Vernois and Bec- 
 
 querel) 88.908 0.138 2.666 3.924 4.364 
 
 Average of 14 Analyses (Simon) 88.360 0.230 2.530 3.430 4.820 
 
 Milk of colored women. 
 
 Average of 18 Analyses (Mott) 86.340 0.600 4.030 3.320 5.710 
 
 AVEKAGE. 
 
 WOMEN. 
 White. Colored. 
 
 Specific gravity 1 .028 — 1.035 1.025 — 1.037 
 
 Water and volatile subst 88.0 — 90.0 8C.0 — 90.0 
 
 Salts 0.2— 0.5 0.3— 0.75 
 
 Albuminates 2.0 — 4.0 1.3 — 4.0 
 
 Fat 2.5— 5.0 4.0— 5.0 
 
 Milk sugar 4.0 — 6.0 5.0 — 6.0 
 
 Average composition of colostrum : 
 
 Water 80.0 — 86.0 
 
 Salts 0.3— 0.5 
 
 Albuminates 8.0 — 10.0 
 
 Fat 2.5— 5.0 
 
 Milk sugar 4.0 — 5.0 
 
 Tlie reports on the results of tlie examination of woman's 
 milk must contain the items given, and also : 
 
 1. Specific gravity. 
 
 2. Reaction. 
 
 3. Age of woman, race, and color of hair. 
 
 4. Period of lactation ; also, if the sample examined is 
 
 from the right or left breast, or an average from 
 both ; quantity of milk obtained, and at what time 
 after last nursing ; time of day. 
 
 5. How often delivered. 
 
 6. Is menstruation present, or sickness ? 
 
 7. Constitution. 
 
 8. Mother's support. 
 
 9. Health of infant. 
 
 10. Weight of infant, if it can possibly be obtained. 
 
60 
 
 Milk from the Breasts of Newly-born 
 Infants. 
 
 It frequently occurs that the breasts of newlj-born infants con- 
 tain considerable quantities of a secretion of the characteristics of 
 milk (Hexenmilch). Slight pressure will furnish it in single drops. 
 The microscope reveals the presence of real fat or milk globules, 
 together with detached cells and colostrum corpuscles. It contains, 
 according to an analysis made by Schlossberger : 
 
 Water 98.750 
 
 Salts 0.050 
 
 Albuminates 0.365 
 
 Fat 0.082 
 
 Milk sugar 0.065 
 
 99.312 
 It has likewise been observed that men and male animals, in 
 rare cases, yield a secretion from the breasts, resembling milk 
 (Bock's milch). 
 
61 
 
 INFANTS' MILK-FOODS 
 
 IN POWDER. 
 
 History : For the last ten or twelve jears a food for infants, 
 ^called milk-food, has been in the market. This was first prepared 
 by a German, H. Nestle, in Yevej, Switzerland, and consists of 
 prepared wheat flour and condensed milk. At the present time 
 quite a number of milk-food factories are in existence, mainly in 
 Switzerland, Germany and England, each of which works by 
 a method of its own. The United States possesses but one estab- 
 lishment, and this only since 1881, under the management of the 
 author. 
 
 Definition: All milk-foods are combinations of milk with 
 specially prepared cereals and other flours. Other preparations, as 
 maizena, flours of arrowroot, leguminosae, barley, rye and oats, 
 should be sold as such to prevent the formation of the erroneous 
 impression that they contain milk, and are intended as food for in- 
 fants. 
 
 The following substances constitute the milk-foods of commerce : 
 
 1. Water and volatile (aromatic) substances. 
 
 2. Salts, especially alkalies and earths. 
 
 3. Milk fat and vegetable fat. 
 
 4. Milk albuminates and vegetable albuminates. 
 
 5. Soluble carbohydrates: milk and cane sugar, glucose, dex- 
 trine and soluble starch. 
 
 6. Insoluble carbohydrates and starch. 
 
 7. Cellulose in very small quantity. 
 The properties of milk-food are : 
 Odor normal : Agreeable, pastry-like. 
 
 Abnormal only when spoiled by age or exposure ; it is then 
 sour or mouldy. It may be decidedly rancid (tallow-like) from ex- 
 posure or the use of moist flour in the manufacture. A slightly 
 rancid odor disappears easily on boiling, and does in no way 
 impair the use of the food. This odor is produced by the presence 
 
62 
 
 of volatile acids of the fatty series, and forms readily in all milk 
 products, especially those which are prepared with the aid of flour. 
 
 Taste : More or less sweet, mainly derived from the admixed 
 condensed milk. 
 
 External normal aj>pearance : Most foods appear as a more 
 or less line powder of a whitish to yellow color ; lately they have 
 also been brought into the shape of tablets, obtained by the appli- 
 cation of high pressure. 
 
 Abnormal appearances : Yegetable mould and animalculse 
 are met with only in very old and carelessly exposed articles, 
 especially when it had been packed in defective boxes, or when it 
 had been kept in damp places. 
 
 Microscopical Examination. 
 
 This aims to recognize : 
 
 1. The general structure of the powder. 
 
 2. The butter globules of the milk. 
 
 3. Probable abnormal qualities. 
 
 The bulk of these milk-foods consists of carbohydi-ates which 
 appear differently, according to their preparation previous to the 
 admixture of the milk. They are either used in the crude state, or 
 after being diastasized or baked. 
 
 Without going into the details of the questions of physiology 
 and chemistry of starch, it will be well to give a few foots relating 
 to this substance. 
 
 Starch heated with much water loses, already at a temperature 
 of from 60 to 70° C, its peculiar characteristics by which it can, 
 otherwise, easily be recognized under the microscope. Some kinds 
 of starch show after careful roasting plainer and more easily recog- 
 nizable properties than they possess when they are in the raw state. 
 In examining a starch we can, therefore, use this process for the 
 determination of their origin. The starch granules in bread gener- 
 ally retain their characteristics. 
 
 Careful heating to 100° C. increases the size of the granules. 
 The structure and the navel become more distinct, and the shape 
 becomes more round. Under the influence of a temperature of 
 150*^ C, most granules burst, and then the characteristic structure 
 
disappears ; those -which stand the temperature -without bursting, 
 appear then smaller ; structure and navel become indistinct and often 
 unrecognizable. 
 
 The starch granules from the crust of English biscuits are gener- 
 ally somewhat smaller than those from the center, on account of the 
 more direct influence of the heat upon the outside during baking. 
 The same is the case with bread. The straight lines marking the 
 strata appear, after roasting, wavy, caused by the irregular expansion 
 of the layers. The presence of these wavy lines, when well defined, 
 is decisive in the question -^-hether the starch had been roasted or 
 not. Frequently it is easier to decide whether a starch had been 
 roasted at between 100 to 150° C, than to come to a decision re- 
 garding the origin of the starch. 
 
 The magnifying power of the microscope should, for these ex- 
 aminations, be not too small, since often minute details must be ob- 
 served. It is also advisable to make all observations with the same 
 lenses. The size of the granules is thus easier remembered and rec- 
 ognized, and the diagnosis thereby greatly facilitated. 
 
 A magnifying power of from 400 to 500 diameters is sufficient 
 for all purposes. 
 
 Microscopical Examination for 
 Carbohydrates. 
 
 To prepare a sample of milk-food for examination, the fat should 
 first be removed from 0.5 to 1 grm. in tlie apparatus devised for 
 fat determination, and described on page 26. Some of the sub- 
 stance is then brought on a slide, and mixed with one drop of a 
 mixture of equal parts of glycerine and water. This mixture is 
 preferred, since in pure water the granules swell too rapidly, while 
 with pure glycerine no distinct picture can be obtained. Milk-food 
 is very finely-ground, and it is, therefore, natural that not all the 
 particles in the field of vision will show the required character- 
 istics. These can safely be neglected, and it is, therefore, only 
 necessarj' to observe such as will present sufficient characteristics 
 for classification. 
 
 A microscopical examination is to be considered only as a qual- 
 itative, and never a quantitative, test in the case of milk- food. 
 
 The presence of starch can also be determined by the iodine 
 reaction. The result thus reached is, however, too general and, 
 
64 
 
 therefore, of little value. The charaoteristic forms of kinds of 
 starch met with in the composition of milk-foods, are the following : 
 
 SAAfPLES OF STARCH AS SEEN BY MEANS OP THE MICROSCOPE. 
 MAGNIFYING POWER, 300 DIAMETERS. 
 
 
 starch of Wheat. 
 
 0_0 G 
 O 
 
 Starch of Barley, 
 
 O "O 
 
 A0@ 
 
 
 Q % 
 
 Starch of Peas. 
 
 0. 
 
 Starch of Beans. 
 This does not exclude that other kinds of starch and flours may 
 be used. In exceptional cases it would, therefore, be well to make 
 comparisons with the cuts as given in Hager, Die pharmaceutische 
 Praxis ; Konig, Nahrungs and Genussmittel, II. ; Hassall, Adulter- 
 ation of Food. 
 
 Microscopical Examination for Butter 
 Globules. 
 
 The presence of condensed milk in milk-foods is easily recog- 
 nized by thepreseace of butter globules. They appear under the 
 
65 
 
 microscope as strongly refractive fat globules of varying size, 
 which, on account of the protection afforded by the flour, do not 
 easily unite, even after dilution with water. 
 
 To better distinguish them, a small quantity of the flour is 
 brought on the slide, and then a solution of iodine in water (1 : 50) 
 is added. Starch and dextrine are both distinctly colored, while 
 the fat globules assume but a very slight yellowish tint on their 
 extreme edge, and are easily recognized by their strong refractive 
 powers. It occasionally happens that even starch granules are not 
 colored by iodine, and may then be taken for fat globules. Addi- 
 tion of potash will swell these and dissolve them gradually, while 
 the fat glol)ules remain unaltered behind. 
 
 Eliza McDonogh, in her dissertation on milk-food, considered 
 herself justified to conclude from the absence of sugar crystals in 
 these foods, that no condensed milk had been used in their prepar- 
 ation, since this always shows sugar crystals. Miss McDonogh and 
 Prof. Wyss would not have come to this conclusion if they had 
 considered the method of manufacturing these foods, which totally 
 differs from that of condensed milk. They even neglected to test 
 these foods qualitatively for fat, and failed, on their microscopical 
 examination, to recognize the butter globules. Their views are, 
 therefore, without value. Owing to the process of manufacture, 
 the butter globules are very finely divided and may, therefore, be 
 easily taken for starch. 
 
 Beside the amylnm and fat globules, the microscope Avill also re- 
 veal other normal constituents, the vegetable albumen and cellulose 
 fragments. 
 
 Abnormal Constituents. 
 
 As abnormal constituents, fungi and the meal-mite may be 
 found, which have their origin in the use of inferior flour. 
 
 Chemical Analysis. 
 
 The reaction of milk-food, after boiling with water, is acid. 
 This is caused by the presence of large quantities of phosphates, 
 and also by the presence of acids of the fatty series. 
 
 Determination of Water. 
 
 3 to 4 grms. of milk-food are taken from the center of a box 
 
66 
 
 and accurately weighed in a previously weighed and covered plati- 
 num dish. They are carefully spread out by means of a spatule, 
 which after use must always be cleaned by means of a small brush. 
 They are then dried in an air bath at from 100 to 110° C, under 
 frequent stirring. The dish and cover are placed in a dessicator 
 to cool, and then weighed. This must be repeated until the weight 
 remains constant. 
 
 Determination of the Ash and Phosphoric 
 Acid. 
 
 The combustion for the determination of the ash must be carried 
 out at as low a temperature as possible, so that none of the more 
 volatile constituents of the ash are lost by volatilization. It is best 
 to operate as follows : The whole is heated to complete carboniza- 
 tion of the contents, which are then transferred to a porcelain dish 
 and extracted with water. The solution is then filtered off. The 
 filter and the residue upon it are then again ti-ansf erred to the 
 platinum dish and, after drying, incinerated. The water solution, 
 unless it be preferred to determine it separately, is then, together 
 with the ashes, evaporated to dryness, then heated to a dull red 
 heat, and allowed to cool in a dessicator. It is then weighed. 
 
 The determination of the phosphoric acid is carried out after 
 the manner described on page 23. 
 
 Determination of Fat. 
 
 Some of the milk-food from the center of the box is placed 
 into a dry stoppered test tube, which is weighed. From 2 to 
 3 grms. are then brought upon a dry filter resting in a small fun- 
 nel. The tube is then re-weighed, the difference being equal to 
 the quantity placed upon the filter. The funnel, with contents, is 
 then dried in an air bath, at from 80 to 100° C, for a short time, 
 to remove the bulk of the moisture. Filter and substance are then 
 transferred from the funnel to the funnel belonging to the appa- 
 ratus described by the author for the determination of the fat. 
 This funnel is then adjusted to the weighed flask, and ether, free 
 from alcohol, is poured upon the filter, care being taken that none 
 of the food is carried over the edges of the filter. When the flask 
 is about half filled with ether, the apparatus is connected, and the 
 
67 
 
 flask heated so that the filter is continually immersed to about one- 
 half its height in condensed ether. The complete extraction of 
 the fat requires from one to two hours' treatment. The ether is 
 then carefully distilled off, the last traces being removed by heat- 
 ing in an air bath at from 100 to 110° C, while the flask is placed 
 into a horizontal position. After cooling in the dessicator, the 
 flask is weighed, the increase corresponding to the amount of 
 fat contained in the quantity of sample taken. 
 
 Determination of the Soluble Carbo- 
 hydrates. 
 
 In the determination of the soluble carbohydrates, it is of im- 
 portance that the directions for use, as established by the manu- 
 facturer, should be carefully considered. The manufacturer's 
 claim in regard to this is fully justified by the fact that more sol- 
 uble carbohydrates are contained in the food after its preparation, 
 according to the directions, than are contained in the food previous 
 to such preparation. The value of an analysis which gives the 
 composition of the food as it is employed, is, likewise, the only 
 guide which a physician has for the determination of the value of 
 a milk-food. 
 
 In the case of milk-foods containing diastase, we take 1 part of 
 milk-food and 10 parts of distilled water, and treat this mixture 
 carefully according to directions. In other respects, the method 
 of analysis is the same as for other milk-foods. 
 
 In the case of ordinary milk-foods, we take for 1 part 10 parts of 
 water, or for from 2 to 3 grms., the ordinary quantity taken, from 20 
 to 30 c.c. water. The mixture is then heated to boiling, and kept 
 boiling for five minutes with continual stirring. It is then allowed 
 to cool. This process should be accelerated by blowing and stirr- 
 ing, to prevent the formation of a skin on the surface. This part 
 of the operation is best carried out in a porcelain or platinum dish, 
 which should be large enough to conveniently hold the double 
 quantity of the fluid used. After cooling, the contents are trans- 
 ferred to a beaker of 150 to 200 c.c. contents, the material adher- 
 ing to the sides of the vessel being carefully washed with 100 c.c. 
 alcohol, of 50° Tr., into the beaker, so that the sediment therein 
 is not disturbed. The whole is allowed to stand over night. The 
 clear fluid is then first drawn off by means of a siphon and filtered 
 through a dry filter. Finally the precipitate is washed on the filter 
 
with 100 c.c. alcohol of 50° Tr. The filtrate is thus brought to 
 about 220 c.c. It is then carefully evaporated on a -water batli to 
 about 50 c.c, refiltered, when necessary, and finally evaporated to 
 dryness in a weighed platinum dish. The drying is finished in an 
 air bath at from 100 to 110° C, and is to be continued until no 
 further loss of weight is observed. To facilitate the drying, it is 
 well to add to the solution, which has been concentrated to about 
 10 c.c, some absolute alcohol fi'om time to time, whereby the carbo- 
 hydrates are precipitated, and then to spread the mass over the sides 
 of the dish by means of a spatule. Evaporation is thus greatlj' accel- 
 erated. When constant weight has been reached, the contents of 
 the dish are incinerated, and, after deducting weight of dish and 
 ashes from the weight first determined, we obtain the weight of 
 the soluble carbohydrates. 
 
 Determination of Insoluble Carbohydrates. 
 
 The residue from the alcohol treatment is transferred into a 
 flask of 400 c.c contents, and then 200 c.c of'M^ater and 20 c.c. 
 pure hydrochloric acid are added. Loosely covered with a cork, 
 the flask is inserted into the water of a boiling water bath, and 
 kept there for from three to four hours. The inversion will be 
 completed by this time. The contents of the flask are then care- 
 fully neutralized, whereby any albumen which may have gone into 
 solution under the influence of heat and acid, is precipitated. The 
 neutralized solution is then filtered through a ribbed filter, flask 
 and filter being wasl)ed until the filtrate measures 500 c.c. The 
 amount of sugar in this solution is determined by Fehling's solu- 
 tion as previously described. For the calculation of starch, 
 Sachsse's figures, 108 glucose = 99 starch, have been accepted. 
 
 CALCULATION. 
 
 Supposing that 2.093 grms. substance had been used for the de- 
 termination of soluble and insoluble carbohydrates, and that, of the 
 sugar solution obtained by inversion, 2S c.c had been required for 
 5 c.c Fehling's solution, we would find the starch by the following 
 equations : 
 
 28 : 0.025 == 500 : X or X = O.U 
 108 : 99 = 0.44 : X or X = 0.403 
 
 2.093 : 0.403 = 100 : X or X = 19.24 
 per cent, of insoluble carbohydrates (amylum). 
 
69 
 
 Cellulose : A method for the accurate determination of cellu- 
 lose is not known. For practical purposes, it is generally sufficient 
 to estimate it as being present to the extent of 0.5 per cent. 
 
 Determination of the Albuminates. 
 
 It has been customary to calculate the albumen and albumi- 
 noids in milk-foods by determining the nitrogen. The figure ob- 
 tained for nitrogen was then multiplied by (J. 25, it having been 
 accepted that the nitrogenous part contained 16. per cent, of nitro- 
 gen. This presumption is false. The nitrogenous substances go- 
 ing into the composition of milk-food contain from 15.5 to 18.5 
 per cent, of nitrogen. From this it is evident that results reached 
 by the determination of the nitrogen cannot be accurate, and it is, 
 therefore, useless to speculate as to the method, which in this case 
 is to be preferred, Dnmas' or Will-Yarrentrapp's. For all the other 
 constituents sufficiently accurate methods exist. Albumen is, 
 therefore, here as in the case of condensed milk, determined by 
 difference. 
 
 Reports on Milk-foods. 
 
 must contain : 
 
 General description : Gross and net weight of packages, their 
 suitability, and, if possible, the price. 
 
 description of trade mark : Remarks on fancy claims upon 
 the labels, as would be, for instance, the claim of a complete sub- 
 stitute for breast milk, etc. 
 
 Physical description: Ap]3earance, odor, taste, microscop- 
 ical examination. 
 
 The chemical analysis shoiUd state: 
 
 Water and volatile substances. 
 
 Salts (phosphoric acid). 
 
 Fat. 
 
 Albuminates. 
 
 Soluble carbohydrates. 
 
 Insoluble carboliyd rates. 
 
 Cellulose. 
 
 Statement giving the analytical method by which these results 
 were obtained. 
 
70 
 
 Hygienic Demands of the Manufacturers of 
 Milk-foods. 
 
 The German society', "Fuer oeffentliche Gesundheitspflege," 
 has rightfully demanded that each manufacturer of milk-food shall 
 attach to each package of his food an analysis stating the average 
 quantities in which its constituents are present. It would be very 
 desirable if the sanitary authorities of all countries would adopt 
 and carry out such measures for the benefit of the health of infants, 
 who depend upon this food. Why should the manufacturer of 
 milk-food not be held equally responsible as dealers in milk and 
 other food substances ? 
 
 The various milk-foods in the market vary in composition as 
 follows : 
 
 A verage. 
 
 Water 5.0 to 10. per cent. 7.50 
 
 Salts 1.5 to 3. '' 2.25 
 
 Fat 4.0 to 7. " 5.50 
 
 Albumen 9.5 to 18. " 13.25 
 
 Sol. carbohydrates. ... 35.0 to 55. " 45.00 
 
 Insol. " ... 15.0 to 35. " 25.00 
 
 Cellulose 0.5 to 1. " 0.75 
 
 99.25 
 From this it is evident that the various brands of milk-food 
 vary considerably. The greatest variations among solids exists in 
 the albuminates and insoluble carbohydrates, which differ in the 
 first almost, and in the second over, loO per cent. This is, no 
 doubt, a considerable difference, and must greatly influence the 
 prosperity of the infant depending on these foods for nourish- 
 ment, as it should the buyer, who, in most cases, will have to pay 
 the same price, be the food a good or an inferior article. 
 
 This desired interference of the sanitary authorities is, however, 
 not meant as consisting in the upholding of ideal desires, which 
 practically cannot be realized. What is wanted is a food which in 
 its composition, i. (?., the relations of the constituents, resembles 
 breast milk, and which is distinguished by its stability. 
 
 In considering what has practically been done in this field of 
 manufacture, we can safely say that the possibility of the solution 
 
n 
 
 of this problem has practically been proved by some manufacturers 
 in Switzerland and Germany. It is also a fact that itovr even bet- 
 ter preparations are in the market than correspond to the average 
 composition given above. 
 
 In the face of these facts, it is astonishing that the milk-food 
 of least rational composition, Nestle's, is yet the one which phy- 
 sicians generally recommend. Analyses of five chemists : F. Hof- 
 mann, J. Konig, Miiller, P. Radenhausen and N. Gerber, give for 
 the same, on the average, the following composition : 
 
 Average of 
 Nestle' s. all Milk-foods. 
 
 Water 6.74 7.50 
 
 Salts 1.77 2.25 
 
 Fat 4.20 5.50 
 
 Albuminates 9.75 ]3.25 
 
 Carbohydrates 76.92 70.00 
 
 The difference in the most important factor, the albumen, is 
 sufficient to show the great improvements made by others. 
 
 Author considers it of vital importance tliat a rationally com- 
 pounded infants' milk-food should contain at least 
 
 2 per cent, salts, 
 5 per cent, fat, and 
 13 per cent, albiiminates, 
 
 and that manufacturers should be compelled to adopt this standard. 
 
 Practice has taught that such milk-foods can be manufactured. 
 Careful investigations have proved that, for a rational food, it is 
 of greater importance to adhere to a certain proportion of albu- 
 men, fat, and salts, to the carbohydrates, than to consider the 
 shape in which these carbohydrates are presented. It is for this 
 reason that the author is in favor of the relations of the main con- 
 stituents as they have been given above. 
 
 Indigestion with children will increase, when a food is lacking 
 in albumen, but contains, in its place, soluble carbohydrates ; the 
 first is, therefore, of greater importance than the latter. 
 
 If a sanitary governmental control of milk-foods should be in- 
 troduced, as it has been done already for milk, it is evident that 
 each manufacturer will be compelled to work better and on a more 
 rational plan, than is frequently done at the present time. It is 
 
72 
 
 then to be hoped that the expressions of Albu, of Berlin, and 
 Jaeobi, of New York, to the effect tliat these manufacturers work, 
 not for the welfare of mankind, but for their own purse, will 
 cease to be true. 
 
 It is evident that these two physicians do not value the com- 
 bined efforts of chemical science and capital very highly; yet those 
 who think differently should be on their guard, that they do not 
 allow themselves to be blinded by either reclame or fame of manu- 
 facturers who have failed to adapt their products to the progress of 
 our knowledge. 
 
 The packing of the article should be such that it reaches the 
 market in good condition in every respect. 
 
 If, on the statement of pliysicians or sanitarians, the article is 
 found to be not in a perfect condition, the manufacturer ought to 
 be notified before the results of such inspection are made public, 
 since it frequently happens that these preparations are not stored 
 with those precautions which are required to insure that they reach 
 the consumer in a good state. 
 
78 
 
 GOVERNMENTAL CONTROL OF THE 
 MILK SUPPLY. 
 
 The question of how the milk supply of cities should be 
 brought under government control, has of late so frequently been 
 discussed, that we propose to give here merely fundamental expla- 
 nations, but based upon extended experience of the matters con- 
 nected with the hygiene of milk. The milk reaches our markets 
 in a variety of conditions; sometimes it is the natural product; 
 sometimes it has been skimmed or watered ; sometimes both pro- 
 cesses have been resorted to; sometimes the milk is fresh, good- 
 flavored, and shows good keeping qualities ; but frequently it is 
 stale, of bad taste, and apt to get sour. The vessels used for 
 transporting it are not always the cleanest, and often no precau- 
 tions are taken to keep it cool while it is transported or stored. 
 
 For these reasons, it is not to be wondered that the inhabitants 
 of cities do not use this otherwise excellent food to such an extent 
 as they should and might, if they had the guarantee that only a 
 rich, cleanly-treated, well-flavored, and unchanged milk would be 
 offered them. 
 
 Milk is a product of rather complicated composition ; and it is, 
 by no means, an easy task to ascertain the quantities of the valu- 
 able constituents which it contains. It is, therefore, of the great- 
 est importance to the inhabitants of especially the larger cities to 
 know that the products which reach the market have to pass sani- 
 tary inspection. 
 
 In most of the larger cities, this control has been assumed by 
 the government ; but it is frequently carried out, not only in an 
 unrational, but also a very superficial manner. Science and justice 
 are certainly not furthered when, even now, milk is passed or con- 
 demned merely upon the results obtained by the use of the lacto- 
 densimeter alone, or in combination with a cremometer. While 
 many dealers, by the use of such primitive methods, have escaped 
 the deserved punishment, others, who were entirely innocent, have 
 been punished. It is, therefore, at the time, and, in the interest 
 
of sanitary welfare, that the composition of a normal milk be de- 
 fined, for the purpose of establishing a sure guide for rational 
 milk inspection. 
 
 It is our purpose to establish such points as may be deduced 
 from many years' practical experience and a strictly scientific treat- 
 ment of tlie entire subject. 
 
 To pronounce a milk as good, bad, or adulterated, can, doubt- 
 less, be done only by regarding special laws, which must be ob- 
 tained by careful observation and thousands of examinations, in- 
 cluding the different races living under varying circumstances in 
 various countries, and under the influence of different climates. 
 But despite this well-acknowledged requirement, we meet every- 
 where with the passage and promulgation of ordinances which are 
 in direct opposition to this only rational plan. Such ordinances, 
 therefore, not only cause the drawing of false deductions, but, also, 
 the use of more serious adulterants. 
 
 This wrong is frequently committed by professors and others, 
 who, proud of their general learning, are frequently ignorant even 
 of the most exact methods of analysis, or of the latest investiga- 
 tions regarding milk, or the practice of dairy industry. The dairy 
 industry and governmental milk control require, at the present 
 time, as well specialists as there exist in other branches of applied 
 chemistry. 
 
 It is the practical specialist, and not the professor, who must de- 
 cide in cases before the courts. In the examination of milk, it must 
 always be considered that a difference exists between milk, in its 
 physiological bearing, and market milk ; for while, in the first, the 
 constituents may be present in greatly varying proportions, we 
 may demand, in the latter, a maximum and minimum quantity of 
 the whole, and all the single food substances which constitute milk. 
 
 The question how a market milk — which is generally the yield 
 of several cows mixed — may vary, has, for many localities, not yet 
 been determined. It is, therefore, of importance, when it is con- 
 templated to introduce government control, that the milk of many 
 cows and whole dairies be frequently examined, so that, for these 
 localities, average figures may be obtained, which may serve as a 
 guide. Average figures should, however, be only calculated from 
 such examinations as comprise the yield of whole dairies, and not 
 only examinations which are made of the milk of single cows. 
 
15 
 
 While, as yet, the average figures obtained by the examination of 
 the mixed milk of cows supplying one dairy, has, in all countries, 
 been the same, we find frequently in the milk of single com^s great 
 abnormalities, caused by the influence of race, age, constitution, 
 food, time of milking, heat, quantity, season, or whether the cows 
 are on pasture or housed. 
 
 Another desideratum of importance is the method by which 
 analytical results are obtained. They must naturally be exact, and 
 the examinations must be continued for a considerable time, care 
 being taken that physiological and pathological data are carefully 
 noted. This is, unfortunately, frequently omitted. 
 
 To facilitate a control of the market milk, on the part of the 
 authorities, it becomes, therefore, necessary that the limits of com- 
 position of a normal milk, and its physical properties, be defined, 
 in order to avoid reproach and tedious explanation. To fix such 
 limits is, however, not without danger. If we aslt. too much, we 
 risk that unjust sentences are administered, and, moreover, that 
 the judge will be tempted to be exceedingly lenient in such cases. 
 If we lower the standard too much, we risk that adulterations of 
 minor extent escape punishment. 
 
 Our own standard, which is based upon thousands of examina- 
 tions made by various investigators, and which has been practically 
 proved as good and just, will be given further on. 
 
 It has previously (see page 39) been stated that the adulteration 
 of milk may be practised by the following means : 
 
 1. Addition of water. 
 
 2. Skimming. 
 
 3. Skimming and addition of water. 
 
 4. Mixing of skimmed milk with whole milk. 
 
 5. Addition of foreign substances, to prevent detection of milk 
 adulterated by any of the processes in 1 to 4. 
 
 Watering and skimming, and the mixing together of such de- 
 teriorated products, or the mixing with whole milk, are the ordi- 
 narily practised means of adulteration. Other substances than 
 water are rarely employed, and then only when it is intended to 
 re-establish a normal appearance of milk which has either been 
 adulterated or which is naturally inferior. The substances used 
 for this purpose have been enumerated on pages 41-43, where 
 also the methods are given by which they may be detected. 
 
76 
 
 The so frequently praised microscopical examination is of little 
 value unless it be for the determination of foreign substances, as 
 blood, pus, colostrum, detritus, etc., or solid adulterants. For the 
 determination of the percentage of fat, it is without value, though 
 it is correct, that a milk shows the butter globules in all the sizes 
 as they are recognized to occur in normal milk, but further apart, 
 when it had simply been watered. The want of the larger and 
 medium-sized globules may indicate skimming, since the larger 
 globules are known to rise sooner and easier. They are the lirst 
 to form the cream, and disappear, tiierefore, with the removal of 
 thi.-> first-formed cream. 
 
 The greatest difficulty exists in getting uniform samples for 
 microscopical examination, as was first shown by Conrad, who has 
 proved that, in examining woman's milk, even the same sample, 
 carefully mixed and sampled by an arrangement to control the 
 quantity taken for one slide, will give results showing differences 
 in number, size and distribution of the fat globules. The methods 
 used for estimating the number of globules are, moreover, arbi- 
 trary and uncertain. Wc will later on give a more satisfactory 
 method for the determination of fat. 
 
 Determination of Specific Gravity. 
 
 The specific gravity of milk depends upon three points: The 
 substances, as milk sugai', salts and albuminates, dissolved or con- 
 tained in the water which forms part of the milk, in a diffused, 
 gelatinous condition, increase the specific gravity, while the sus- 
 pended fat globules diminish it. Increase of temperature dimin- 
 ishes the specific gravity likewise, while decrease of temperature 
 ■will increase it. The specific gravity is determined, for practical 
 purposes, with sufiicient accuracy, by the use of a milk areometer, 
 the so-called lactodensimeter. 
 
 It should be remarked here that the name lactom.etei\ ^hicli 
 has been given to these instruments, is wrong, and should cer- 
 tainly not be used by scientifically educated persons. It conveys 
 a wrong impression ; for, to this day, we have no instrument, and 
 least in the lactodensimeter, which furnishes us a direct measure 
 for the quality of the milk. 
 
 The best and most exact instruments are those of Quevenne, 
 the inventor of the lactodensimeter, which give, in abbreviated 
 
11 
 
 figures, directly the specific gravity. All other instruments, witli 
 scales differing from this, have been abolished on the European 
 continent. It is only in England, and through English influence 
 in America, that instruments with arbitrary scales are as yet in 
 U6e. The principle upon which' these are constructed is a wrong 
 one, and they possess, moreover, useless appendages. It is never 
 required to use the lactodensimeter for degrees below a specific 
 gravity of 1.015, and all those degrees below this are, therefore, 
 useless. The scale appears long, but its actually useful part is ex- 
 ceedingly short. 
 
 Quevenne's areometer has, for the specific gravities of from 
 1.015 to 1.040, on a scale of 5.5 era. length, 25 degrees, and 
 allows thus easily the reading of half degrees ; while a so-called 
 lactometer has, on a scale of 7.8 cm., 120 degrees, with a space of 
 0.065 cm. for each degree. For milk, this subdivision lays below 
 the actual possibility of accurate reading. 
 
 The reason that such areometers, with arbitrary scales, have 
 remained in use for so long a time, is explained by the fact, that men 
 without intimate knowledge of the subject, and without desire to 
 obtain it, find it easier to go on with their investigation by making 
 a so-called authority responsible for their results, without consider- 
 ing that many of these so-called authorities frequently adhere to 
 and defend their wrong positions, even after they have been 
 proved to be untenable. 
 
 Another drawback for the practical application of those lacto- 
 meters is to be found in the fact that no tables exist for the correc- 
 tion of the error created by the reading of the instrument at a 
 temperature which is not the normal temperature. Every saniple 
 mufit be cooled or warmed to 60° F. The usefulness of the in- 
 strument is thereby considerably lessened. 
 
 Description of Quevenne's Lactodensimeter. 
 
 The lactodensimeter of Quevenne is an ordinary areometer. 
 It is made of glass, and is 22 cm. long. It consists of a hollow 
 body, kept in an upright position by a weighted globe at its under 
 end ; above, it carries the 6 cm. long stem which bears the scale. 
 
IS 
 
 The dimensions of the instrument are chosen to insnre suflBcient 
 ease of motion and to prevent unnecessary length of stem. 
 
 Centesimal Galactometer, or Lactometer. Quevenne's Lactodeusimeter. 
 It is weighted to such an extent, that it sinks in a salt solution 
 of 1.042 specific gravity, at 15° C, to a point which is marked 42. 
 Milk mixed with half its volume of water lias a specific gravity 
 of 1.014 to 1.016. Therefore, a second point is determined by 
 putting the areometer in a salt solution of 1.014 specific gravity, 
 at 15° C. This point is marked 14. The space between 14 and 
 42 is then divided by lines in 28 equal parts, or degrees. The dis- 
 tance between each two degrees is about 2 m.m. It is, therefore, 
 not difficult to read the specific gravity easily to 0.0005 with suf- 
 ficient accuracy. 
 
79 
 
 The lactodensimeter of Quevenne-Miiller bears the scale in a 
 brass tube, and is, therefore, preferred by those who find the work- 
 ing with glass instruments unprofitable. It bears two scales — the 
 one to the right to be used for whole milk, and the one to the left 
 for skim milk. 
 
 The meaning of the fractions on the right — iV (29 — 26), ts 
 (26 — 23), etc. — is that the addition of water to whole milk is about 
 as corresponds to these fractions. On the left of the scale the 
 same is repeated, but the fractions appear in different places, 32.5 — 
 36.5, corresponding to normal unwatered skim milk. The fractions 
 on the left stand about 4 degrees lower on the scale, for the reason 
 that the specific gravity of milk gains 4 degrees by the process of 
 skimming. 
 
 This double scale allows of a far more extended application 
 of the lactodensimeter than those which only give the specific 
 gravity. 
 
 It would, perhaps, be even better to construct the densimeters 
 with a scale ranging from 1.020 to 1.040, and divide these 20 de- 
 grees over the space occupied by 28 degrees. The reading of 
 subdivisions of degrees would thereby be greatly facilitated. This, 
 from a practical point of view, is easily justified by the fact that, 
 in doubtful cases, at any rate, all milks showing specific gravities 
 outside of the limits 1.027 to 1.033, must be analyzed. 
 
 It is, likewise, to bs recommended to have the thermometer 
 inclosed into the areometer, as is done with those which are manu- 
 factured in Germany. 
 
 Each lactodensimeter must be carefully examined for its accu- 
 racy, by comparing the results obtained with it with those obtained 
 by means of a specific gravity bottle, and only instruments giving 
 correct readings for at least three decimals should be employed. 
 
 Determination of the specific gravity : The apparatus neces- 
 sary for this are : 
 
 1. A well adjusted and examined lactodensimeter of Quevenne, 
 with or without inclosed thermometer. 
 
 2. An accurate Celsius thermometer. 
 
 3. Glass cylinders sufficiently high and wide to admit of the 
 introduction and use of the lactodensimeters. 
 
80 
 
 A. — Exatniriation of whole milk and market 7nilk: 1. The 
 
 inilk is well mixed and poured into a cylinder, care being taken 
 that the milk runs slowlj' down its sides, by holding it in a some- 
 what inclined position. Thus the formation of foam, which would 
 materially interfere with accurate readings, is prevented. 
 
 2. The thermometer remains in the milk for about two minutes 
 before the temperature is quickly read and noted. If the milk be 
 fresh from the cow, it should be cooled by holding the cylinder 
 containing it in cold water. The thermometer is thereby used for 
 stirring the milk slowly, and for observing the gradual reduction 
 of temperature, which is brought as near as practicable to 15° C. 
 (59° F.) If, on the other hand, the temperature of the milk, as 
 during winter time, is very low, it must be gradually raised to 
 from 15 to 20° C. 
 
 3. The stem of the lactodensimeter, which bears the scale, is, 
 to prevent adhesion and to enable a more accurate reading, drawn 
 between the closed lips, and then inserted into the milk until its 
 surface reaches the degree marked 30. It is then liberated to find 
 its level. If it should swim without changing its position, it is 
 pushed from one to two degrees deeper, and again liberated to find 
 its level. If the same reading is obtained, the degree is noted. 
 
 4. All readings of the lactodensimeter give accurate density 
 only at a temperature of 15° C. AVarmer milk is lighter ; colder, 
 on the contrary, heavier. If the density has been observed at an- 
 other temperature, the actual density is found in the following 
 first table for whole milk, by using it in the following manner : 
 
 The first vertical column of figures gives the degrees of the 
 lactodensimeters read directly. The fii-st horizontal line gives the 
 degrees of the Fahrenheit thermometer, the second the correspond- 
 ing degrees on the Celsius thermometer. In order to find the real 
 density, we pass from the degree of the lactodensimeters read, to the 
 right, until we reach the column headed by the degree of tempera- 
 ture observed. The figure at the intersection of both lines gives 
 actual density at 15° C. If, for instance, we found 28°- on the 
 lactodensimeter, at 18° C, we would thus find actual density at 
 15° C. =28.6° = to a specific gravity of 1.0286. 
 
81 
 
 Degrees obskrvbd on the Lactodensimkter. 
 
 
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82 
 
 Degrees observed on the Lactodensimeter, 
 
 
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83 
 
 Good market milk should have a specific gravity ranging from 
 1.029 to 1.033 (29 to 33°). A specific gravity differing from this 
 may indicate either skimming or watering, and in such cases the 
 dairy milk supply should be investigated. 
 
 The simple determination of the specific gravity above is, how- 
 ever, not decisive. Milk consists of substances which are dissolved 
 in water, and which increase its specific weight, and suspended fat, 
 which decreases its specific weight. A skimmed milk will, there- 
 fore, be heavier, and when adulterated with water, may have the 
 same specific gravity as a milk which is ricli in cream. To decide 
 in such cases, it becomes, therefore, necessary to make an additional 
 determination of the quantity of fat present. 
 
 B. — Examination of skimmed milk : The milk under in- 
 vestigation is brought into a wide vessel (tea cup shape), ahd 
 allowed to remain in a cool place (to prevent souring) for 24 
 hours. The cream which has collected on the surface, is then care- 
 fully removed, and the specific gravity of the remainder deter- 
 mined. For temperature corrections the second table (for skimmed 
 milk) should be employed. 
 
 Unadulterated skimmed milk should have a specific gravity 
 ranging from 1.032 to 1.036 (32 to 36°); specific gravities under 
 1.032 indicate adulteration with water. 
 
 On the basis of this observation Quevenne has given the follow- 
 ing table : 
 
 A. 
 
 Whole milk. 
 
 
 B. Skimmed milk. 
 
 Water added. 
 
 1.029 - 
 
 - 1.026 
 
 (29°- 
 
 -26°) 
 
 1.032 (32°) 
 
 10% 
 
 
 Lactodensimeter 
 
 Lactodensimeter 
 
 
 1.026 ■ 
 
 - 1.023 
 
 
 
 1.029 
 
 20% 
 
 1.023 - 
 
 - 1.020 
 
 
 
 1.026 
 
 so% 
 
 1.020 - 
 
 - 1.017 
 
 
 
 1.0236 
 
 Wo 
 
 1.017 - 
 
 - 1.014 
 
 
 
 1.0195 
 
 50^ 
 
 Schroeder and Dietzel found that the specific gravity of the 
 serum of coagulated milk may likewise be used as an indicator for 
 the adulteration with water. A specific gravity less than 1.026 
 indicates adulteration with water. Further investigations regard- 
 ing this point are greatly to be desired. 
 
 The fact that milk, after such investigations as have been 
 described, does not appear normal, may indicate adulteration, but 
 
84 
 
 this may also be caused by pliysiological and pathological pro- 
 cesses. If, therefore, an exact chemical and physical analysis 
 shows deviation from a normal composition, a milk-dealer can, 
 simply, on this fact, not he pronoiiii'ied gidlUj of adulteration^ 
 unless his dairy supply has heen shown to he of a normal compo- 
 sition. 
 
 The so-called "stable test" is applied only M-hen sufficient 
 cause for suspicion is given. It consists in a comparison of the 
 properties of the milk produced by the cows, with those of the 
 one which has been sold. The cows, to this end, are milked in 
 the presence of the inspector and witnesses, if possible on tiie 
 on the same day, or latest, the day after the suspected milk has 
 been found in the market. As it is rarely required to get a 
 thorough knowledge of its composition, the examination is gen- 
 erally confined to the following parts : 
 
 1. Determinations of specific gravity of the whole milk by Que- 
 venne's lactodensimeter, reduced to the normal temperature, 15° C. 
 
 2. The same, of milk which has been skimmed, after 24 hours' 
 standing. 
 
 3. Determination of the fat by means of the lactobutyrometer 
 (not creamometer). 
 
 The milking of the cows must be done at the usual hour, 
 and care must be taken that the udders are well emptied. The 
 milk of all the cows thus milked is then mixed. Yet aside of this, 
 and when the time allows, the milk of each cow may be examined 
 separately. It is well to use for the milking of the cows, a disin- 
 terested person, to be sure that the udder has been completely 
 emptied. Since, however, it frequently happens that cows milked 
 b}' strangers yield less milk, it is as well to let the stable attendants 
 milk fii'st and to let the other merely ascertain whether they have 
 done their duty, and if not, to let him complete the milking. 
 The milk which is at first drawn is always more watery than the 
 one drawn last. There is even a difference in the quality df the 
 milk drawn from the different teats. For this reason, and also to 
 insure complete emptying of the udder, the milking is done cross- 
 ways, milking two teats in diagonal position at a time. Thus the 
 complete emptying of the udder can be best effected. 
 
 After all the milk thus obtained has been well mixed, the tests 
 described above are applied. About one pint is taken for subse- 
 
85 
 
 quent chemical examination in the laboratory, which includes, in 
 the first place, an accurate determination of the fat, and determina- 
 tion of the specific gravity of the milk after skimming. Differ- 
 ences in the properties of the milk for sale and the milk thus obtain- 
 ed, indicate the use of adulterants, and the rest of the sample should 
 then be given to a chemist for further examination, to insure a 
 good case when it should be brought before the courts. Water, 
 solids and fat should be determined. 
 
 The talcing of samples^ and the examination in the stahle, should 
 he done in the presence of witnesses. 
 
 Estimation of the quality of the milk by the specific 
 gravity: The determination of the specific gravity of the whole 
 and skimmed milk, establishes the degree of adulteration by water. 
 
 The percentage of fat establishes the fact whether we have a 
 normal or abnormal milk before us. 
 
 The percentage of water added may be inferred by the use of 
 the table previously given (p. 83). Whole milk should have a 
 specific gravity ranging from 1.029 to 1.033. If the specific grav- 
 ity be less than 1.029, the milk must be considered adulterated if 
 a sample taken from the stable should show a different (higher) 
 gravity. If the specific gravity should be found higher than 1.033, 
 it may indicate the partial removal of the cream. 
 
 If the milk, skimmed after 24 hours' standing, shows a specific 
 gravity of less than 1.032, while unskimmed its specific gravity 
 appears normal, we conclude that the milk under examination had 
 been skimmed and watered. 
 
 The quantity of cream removed is inferred from a 
 
 Determination of the Fat. 
 
 It is to be regretted that as yet for the estimation of fat in 
 milk, Chevalier's creamometer is frequently used. When using 
 this apparatus, the milk is allowed to stand for 24 hours, after 
 which the amount of cream which has risen to the surface, is de- 
 termined. The results obtained from this instrument are very 
 uncertain, and should never be used in proceedings before a court 
 of justice, for the following reasons : 
 
 1. The cream, even under the same conditions, does not rise 
 evenly. 
 
2. Addition of water to milk makes milk appear richer, for the 
 greater consistency of pure milk prevents the easy formation of 
 cream. 
 
 3. The cream rises quicker or slower according to the tempera- 
 ture at which the milk is kept. Moreover, the layer of cream 
 appears larger at lower, and smaller at higher temperatures. 
 
 4. Milk frequently sours, and therefore coagulates before the 
 cream has all risen. 
 
 6. The manner of transporting the milk influences the process 
 of creaming considerably. 
 
 6. The cream constantly varies in percentage of fat. Often it is 
 very rich, then again thinner; sometimes it collects and rises 
 easily, and at other times less completely. 
 
 For comparative quantitative fat determinations, it is advisable 
 to use, in the place of the costly creamometei*, the simpler and 
 cheaper apparatus of Schatzmann (to be obtained through the 
 "Schweizer Molkerei Yersuchsstation, at Lausanne"). 
 
 The points mentioned above do not influence the results, which 
 may be obtained by means of the improved lactobutyrometrictest, 
 whereby the percentage of fat can be determined in milk in from 
 one-half to one hour's time, sufficiently exact, while with Chevalier's 
 crcamometer, we ai-e obliged to wait 24 hours before the very 
 unexact results can be obtained. 
 
 The results obtainable by the lactobutyrometer are not so exact 
 as those which are obtained by a careful chemical analysis, but suf- 
 ficiently accurate for the purpose, differing from the truth in the 
 average not more than 0.2 to 0.3 per cent. Small errors do not, 
 however, influence the usefulness of the test, if we consider the 
 value arising from a quick determination of the fat. 
 
 The following apparatus are required for the application of 
 this test : 
 
 1. Glass rods for stirring the milk. 
 
 2. A water bath to prepare water of 40° C, consisting of a high 
 cylinder of metal, which rests on a dish upon which alcohol maybe 
 poured and ignited, to heat the water to the required temperature. 
 
 3. A glass or metallic cylinder for the water of 20° C. 
 
 4. A Centigrade thermometer. 
 
 5. A drop glass for potash solution. 
 
 6. 3 bottles, one containing ordinary alcohol for burning, another 
 
87 
 
 7. An alcohometer (Tralles) for testing the alcohol. 
 
 8. A tested laotobutjrometer with stopper. 
 
 9. Pipettes for alcohol of 90 to 92° Tralles, and ether, discharg- 
 ing 10 c.c. or 5 c.c. when blown out. 
 
 10. Pipettes for milk adjusted to give 10 c.c. or 5 c.c. between 
 two marks or divisions. 
 
 The whole lactobutyrometric apparatus is generally for sale 
 put up in a case. (See below " Utensils.") 
 
 The principle of the lactobutyrometer is based upon the obser- 
 vation, that alcohol separates from milk which has been mixed 
 with ether, an etheric fat solution, the volume of which stands in 
 au intimate relation to the quantity of fat dissolved in the ether. 
 The method and apparatus were invented by Marchand, and the 
 latter was called by him the lactobutyrometer. 
 
 The lactobutyrometer is a tube of equal width throughout 
 (10 to 12 ra.m.), closed at one end. From this point on the lacto- 
 butyrometer is divided into three equal parts, each being 10 c.c. 
 or 5 c.c. A space equal to about 1 of these parts must remain to 
 allow the contents to be well mixed by shaking. The space be- 
 tween the two upper marks is subdivided into tV c.c. 
 
 While the lactobutyrometer may he used by the inspectors, its 
 results should always be verified by actual analysis, when a case 
 is to be bro\Lght before the courts. 
 
 Lactobutyrometer. 
 
Determination of Fat hj the Lactohutyrometer. 
 
 1. The milk must be thoroughly mixed, by sliaking the bottle, 
 or otherwise by agitation with a glass rod, immediately before it 
 is sampled. If it should be sour, it must be neutralized or made 
 slightly alkaline with potash solution. The pipette marked milk 
 is then filled with the milk above the mark, by suction ; it is then 
 quickly removed from the mouth, and the upper opening closed by 
 the slightly moistened forefinger. By slightly decreasing the 
 pressure, the milk may be made to flow out at the bottom. As 
 soon as the surface of the milk becomes even with the upper mark, 
 the pressure of the finger is again increased, and thereby the out- 
 flow stopped. The under end of the pipette is then brought into 
 the mouth of the lactohutyrometer, and the milk allowed to flow 
 out until its surface becomes even with the under mark. 
 
 If an ordinary pipette is used with only one mark, the last 
 drop is removed by blowing it out. 
 
 2. The pipette marked ether is then filled in a similar manner 
 as described above, with pure ether, and its contents are allowed 
 to flow on the milk in the lactohutyrometer, care being taken that 
 the last drop is brought into the apparatus by blowing it out. 
 
 The tube is then closed with a well-fitting cork, and the whole 
 shaken, lifting the cork from time to time, until milk and ether 
 form a uniform liquid. This takes several minutes. 
 
 During this time the water of 40° C. may be prepared. The 
 cylinder containing the water is placed upon a dish upon which 
 some alcohol is poured and ignited. The alcohol is allowed to 
 burn until the water has reached a temperature of from 40 to 
 42° C, which is observed by a thermometer suspended in the 
 water. The alcohol is then quickly extinguished. 
 
 3. While yet the water is heating, and after the uniform mix- 
 ture of ether and milk has been obtained, the third pipette is filled 
 with alcohol, and the alcohol added to this mixture. The shaking 
 of the tube is then continued, opening the cork from time to time, 
 until all lumps have disappeared, and the precipitate, which has 
 been formed, appears finely flocculent. The lactohutyrometer is 
 then put into the cylinder, filled with water of 40° 0. After 10 
 minutes standing, the fat solution has well separated from the rest. 
 
89 
 
 and appears in that part of the tube which is divided into tenths 
 of cubic centimeters. 
 
 With the aid of cold water and the water 40° C. warm, water 
 of 20° C. is then prepared, and tlie lactobutyrometer is inserted 
 into this. There it remains for from one-quarter to one-half hour. 
 The layer of fat is thereby gonerally yet increased. 
 
 Over the solution containing the undissolved albuminates, an 
 etheric fat solution of high refractive power has accumulated, the 
 volume of which is read by means of the divisions on the tube. 
 
 To this end, the reading is taken from the lower meniscus at the 
 surface down to the even plane where the lower and upper liquid 
 meet. 
 
 The amount of fat corresponding to the tenths of cubic centi- 
 meters of solution read, is found in the following tables. 
 
 The upper portion of the lactobutyrometer contains 5 c.c. sub- 
 divided into tenths, therefore, 50 degrees. Provided the reading 
 at the upper end (lower meniscus) had given 45° = 4.5 c.c, and at 
 the lower end of the fat solution, 31° = 3.1 c.c, the height of the 
 solution would be equal to 14° = 1.4 c.c. 
 
 According to the tables we find the amount of fat = 3.991 
 per cent. 
 
 Remarh : The cleaning of the milk pipette and the lactobutyro- 
 meter is easiest effected in the following manner : Rinse first with 
 concentrated soda solution ; then with water, strong alcohol, and 
 ether, successively. 
 
 Though this determination of the percentage of fat in milk 
 requires more manipulation and time than Feser's lactoscopic 
 method, it must be considered that this latter instrument is ex- 
 pected to give only satisfactory results, when it is in the hands of 
 men well acquainted with analytical chemistry and the handling of 
 the apparatus. As an easy test to be used by milk inspectors, the 
 lactobutyi'ometer is, therefore, to be preferred. 
 
 It requires neither special knowledge nor expertness in its use, 
 and is, therefore, always to be recommended when it is required to 
 make practically accurate determination in the sliortest possible 
 time. The place of an accurate determination of the fat by chem- 
 ical analysis it can, however, not take ; but it will always find its 
 place of usefulness M^hen physicians, inspectors, or dairymen desire 
 to make a fat determination, in case that the lactodensimeter test is 
 insufficient to decide the question of adulteration with certainty. 
 
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91 
 
 Prof. Soxhlet has lately changed the test, in so far as he re- 
 quires a determination of the specific gravity of the etheric fat 
 solution. 
 
 For practical purposes Soxhiet's method is too complicated and 
 costly, on account of the price of the apparatus and the large quan- 
 tities of ether required. For laboratories it is much to be recom- 
 mended. 
 
 Marchand's improved method gives also satisfactory results, 
 and would, for practical purposes, have to be preferred to Soxhiet's, 
 since the apparatus is less complicated and costly. 
 
 Hides regarding the Execution of the Lactohutyrometric Ted. 
 
 1. Milk, ether, and alcohol must be exactly measured in pipettes, 
 each of which is to be used for one of the fluids only. The fluids 
 must be brought into the lactobutyrometer directly from the pi- 
 pettes. 
 
 2. The lactobutyrometer should be well gauged, as in tlie case 
 of these instruments like inaccuracies are liable to occur as in the 
 lactodensimeters. 
 
 3. A large number of experiments have proved that the strength 
 of the alcohol need not be absolutely of a certain standard. Some 
 propose alcohol of 90° Tr., others 91 and 92° Tr. It is certain 
 that an alcohol of from 90 to 92° Tr. gives the best results, and, 
 while the use of an alcohol of less strength is indicated for richer 
 milks, one of greater strength would be required for the examina- 
 tion of a more watery article. 
 
 4. The ether should be very pure 65° = 0.725 specific gravity. 
 
 5. The alkali solution should be 36° B., and not more than one 
 drop of it should be used for each 10 c.c. milk. It should never be 
 added to the alcohol and ether mixture, but to the milk before any 
 of these I'eagents have been added. 
 
 Using these precautions in the examination of a whole milk, the 
 results will always be found to be almost accurate. In examining 
 a milk which has been skimmed, the difference is easily perceptible. 
 A milk, which by the use of the lactobutyrometric test, contains 
 less than 3 per cent, of fat in each of two determinations, should 
 be examined in the laboratory by exact analysis. 
 
 Skimminff and addition of tvater become evident from the 
 decrease in fat and increase of water. It is referred here to the 
 
92 
 
 table previously given on skimmed milk and its percentage of 
 fat. The inspector's report is to be verified by an exact determi- 
 nation of fat and solids. 
 
 Mixing of whole and shimmed milk may be inferred by the 
 data given above. 
 
 Foreign substances in milk: The substances most generally 
 applied have been given on pages 41-43. Also the methods used 
 for their detection. 
 
 Properties of Normal Cows' Milk and 
 Market Milk. 
 
 Normal coivs' tnilJc and milk of commerce must possess an 
 agreeable normal odor and taste — i. e., it should not emit a dis- 
 agreeable odor or possess an alkaline or sour taste. The whole and 
 normal milk of commerce, obtained by mixing the milk of a num- 
 ber of cows, has an average composition as follows : 
 
 Water and volatile substances 87.5 per cent. 
 
 Salts 0.5 " 
 
 Fat 3.5 '' 
 
 Albuminates 4.0 " 
 
 Milk sugar 4.5 " 
 
 Its average specific gravity, according to many thousands of ex- 
 periments, ranges from 1.029 (29°) to 1.033 (33°). It contains in 
 the minimum 3 per cent, of fat and 12.5 per cent, total solids. 
 
 For good and normal cows' milk, these points constitute an in- 
 disputable truth. Each milk which does not come up to this 
 standard is a poor article. 
 
 11 per cent, of solids, 2 to 1^ per cent, of fat, and a specific 
 gravity of from 1.031 to 1.035, indicates that such milk has suffered 
 the loss of one-half its cream. 
 
 9^ to 9 per cent, solids, 1 to |^ per cent, fat, and a specific 
 gravity of from 1.0325 to 1.036, indicates thai the milk is skimmed 
 entirely of its cream. 
 
 The Aim of Governmental Control of the 
 Quality of the Milk Supply. 
 
 The inspection of the ujilk brought upon the market aims not 
 only at the detection of the adulterations, but must be instituted 
 to guarantee to the public that the article which they receive is of 
 
undoubtedly ^ood quality. That the measures used for its dispen- 
 sation are correct, should likewise fall within the scope of the 
 examination. Aside of real adulterations, many other changes 
 occur which are of importance, and which are caused either by 
 sickness, inadequate food and treatment of the animals, but also 
 by the careless handling of the milk. 
 
 For the detection of the first-mentioned causes, the health au- 
 thorities should confer with a veterinarian. 
 
 The question arises here whethei" producers of an inferior arti- 
 cle should not be prevented from selling their milk, and should in- 
 stead be held to find another application for such milk. 
 
 The interest of the public undoubtedly demands that we insist 
 upon such restriction, especially since our advanced knowledge 
 enables the farmer to remedy, by rational treatment, any abnormal- 
 ities thus discovered. If, therefore, any man has made it his business, 
 for the sake of its profitability, to supply milk, he should also be 
 held to bestow all necessary care upon the production of a good 
 article, in the same M'ay as it is exacted from the producers of other 
 food. 
 
 One of the best safeguards would be, if the dealers were strict- 
 ly held to sell their milk for what it is, whole milk, half skimmed, 
 and wholly skimmed milk, with gradation of prices accordingly, 
 and that not, as is generally done, they exact the same price, irre- 
 spective of quality. The sale of a milk at a higher price than 
 would correspond to its grade, should be considered a fraud. Ordi- 
 nances to this effect woxild prevent much wrong-doing^ inany prose- 
 cutions, and also much unnecessary expense of time and money for 
 the entertainment of a large force of milk inspectors. 
 
 Prof. Dr. I. Feser, of Munich, an authority in this branch, says : 
 " The farmer is compelled to remedy existing evils if he is cc»m- 
 " pelled to bring a normal article to market. But I desire to call 
 " attention to the fact, that it is equally desirable to prevent the 
 " sale of milk which is below a certain standard as good milk, even 
 "if it be simply the unadulterated product of single animals re- 
 " duced through insufficient and faulty feeding. The inspection 
 " is, therefore, not only instituted to prevent adulteration, but like- 
 " wise for the exclusion of an article of inferior value. Ordinances 
 " passed for the prevention of adulteration would be powerless, if 
 " it be lawful that milk may be adulterated before its production, 
 " in the body of the animal, by injudicious treatment and feeding." 
 
94 
 
 R. Scliatzniann, in Lausanne, says : " It is not clear, why, at the 
 "present day, the sale of skimmed milk should in many places be 
 " interdicted. Everybody knows that cream and butter are sold 
 " by the same parties who profess that they send so-called good 
 "milk to market. Thus restrained, many producers are led to 
 "commit a fraud, as they may not be able to utilize the skimmed 
 " milk in their own household or for the manufacture of cheese. 
 " And why should the public be prevented from buying a yet ex- 
 " cellent food, if it can be had at a lower price ? The producers 
 " will then not be compelled to commit a fraud, nor will the con- 
 " sumer be defrauded, when he pays for skimmed milk as such." 
 
 Milk-dealers should, therefore, be held to sell their goods for 
 what they are, and at prices ranging according to their quality. 
 
 For larger cities, ordinances to this effect would be of consider- 
 able value, especially as it is, in such cases, frequently impossible 
 to examine the milk at its source. Each dealer in food must know 
 the quality of the article he sells, and if defrauded himself, he is 
 not less liable if he defrauds others. 
 
 General Rules for a Rational Milk Inspection. 
 
 ^.--IN CITIES. 
 
 1. The inspection includes the milk as furnished by the 
 producers as well as the dealers. 
 
 2. At the inspection at the place of sale, the following points 
 should be observed : 
 
 a. Cleanliness in the handling of the milk and the vessels in 
 which it is carried. For transportation as well as storage the use of 
 only such vessels should be permitted, which allow an easy and 
 thorough cleaning. They should have, therefore, sufficiently wide 
 openings. They should neither be made of copper nor zinc, and 
 should not be kept in places which are used as dwelling rooms, or 
 in such places where garbage or other bad smelling substances are 
 near. 
 
 l. The correctness of the measure for retail sales should be 
 verified. 
 
 c. Note should be taken of the quantity of the milk brought 
 to market, and the number of cows which have contributed to this 
 
95 
 
 supply, since it frequently happens that the figures thus obtained 
 are quite out of proportion. 
 
 d. Examine appearance, odor, taste, and reaction. A strongly 
 alkaline or acid milk, or one with bad taste, should be confiscated. 
 The use of preservatives should be considered an adulteration. 
 
 e. Determination of temperature to ascertain M'hether heat has 
 been applied to preserve the milk. A temperature of over 35° C. 
 would indicate that such has been done. 
 
 f. Statements as to quantity and price of the milk. 
 
 g. Each sample taken is given a number, and on the record 
 book the following facts must be stated : 
 
 Name of seller. • 
 
 Occupation of same (producer or dealer). 
 
 Age of same, and residence. 
 
 If the seller be merely dealer, he must state name of producer, 
 and number of cows kept by tlie same. 
 
 h. The sampling of suspicious milk is done after it has been 
 well mixed by a dry and clean rod. One-half liter is then bot- 
 tled, sealed, and labeled in the presence of witnesses. The label 
 on the bottle gives merely the number under which the sample 
 lias been entered in the inspector's book, to avoid that the chemist 
 may be charged with partiality. The samples should be paid for, 
 and, on demand, a similar sample, sealed and labeled, should be 
 prepared for the dealer, that he may have an analysis made at his 
 own expense. 
 
 3. At the laboratory the following tests are made : 
 
 If a sample is to be forwarded to an expert at some distance, it is 
 well to insert the bottle containing it into boiling water for one- 
 half or one hour. It is then sealed and labeled. Milk thus treated 
 will bear transportation easily without souring. 
 
 a. Determination of the reaction of the milk with litmus or 
 turmeric paper. 
 
 h. Boiling of the onilk when strongly acid. 
 
 c. Determination of the specific gravity by means of an ac- 
 curate Quevenne's lactodensimeter, on the fresh milk, and on the 
 milk skimmed after 24 hours standing. 
 
 cl. Determination of the fat by means'of an accurate improved 
 Marchand's lactobutyrometer, or by some other sufficiently accurate 
 method (the creamometer cannot be counted amongst these). 
 
96 
 
 e. Determination of solids b}' approved chemical metjiod. 
 
 The accuracy of the apparatus is of the greatest importance, 
 and the utmost pains should be taken to insure it. It would be 
 well, if from the part of the government, steps be taken to insure 
 that only accurate instruments be brouglit into the market, by ap- 
 pointing a person, whose duty it shall be to test and mark all such 
 instruments which Jiave stood the test. That the instruments, 
 which are sold without this precaution, are almost without excep- 
 tion incorrect, is a notorious fact. 
 
 The work of verifying the correctness is by no means an easy 
 task, and should be given into proper hands. 
 
 JB.— IN THE STABLE. 
 
 The stable test, which can be easily made in smaller cities and 
 villages, is frequently not applicable in larger cities, owing to the 
 distances from which the milk is brought. In such cases an ordi- 
 nance binding the dealer to sell the milk only under such names as 
 indicate its real character, should be substituted. 
 
 Wherever the stable test can be made, and is in use, the fol- 
 lowing rules should be observed. 
 
 a. The milking is to be done, if possible, at the usual time and 
 with the assistance of a disinterested person. 
 
 I. The specific gravity is determined by means of the lactoden- 
 simeter, at a temperature as near as possible to 15° C. 
 
 c. The reaction of the milk is taken. 
 
 d. Samples of about 1 pint are taken for the determination of 
 the fat and specific gravity of the milk skimmed after 24 hours 
 standing. 
 
 e. The number of cows, their age, period of lactation, health 
 and feed, etc., are to be noted. 
 
 f. The book stating the sales during two weeks past, is to be 
 examined, and thus the quantity ascertained compared with the 
 quantity of milk obtained at the time of examination. 
 
 g. General information from attendants as to the feeding of 
 the cows, handling of milk vessels and milk, and quantities of milk 
 used for obtaining cream, is also to be obtained. 
 
 The correctness of the notes taken is to be verified by the sig- 
 nature of a witness. 
 
97 
 
 Proposition Stating the Main Points for an 
 
 Ordinance Regulating the Sale of 
 
 Milk in Large Cities. 
 
 For the protection of the public against fraud and injury to 
 health, the following points suggest themselves. 
 
 1. All dealers in milk should be licensed, and licenses be grant- 
 ed only to responsible parties. The sale of milk by unlicensed 
 parties is prohibited. 
 
 2. A record should be kept of the names, residences and places 
 of business of all licensed dealers. 
 
 3. Dealers should be acquainted with the use of the lactoden- 
 simeter, lactobutyrometer and litmus paper. 
 
 The government should aid this education by free lessons and 
 printed statements explaining the use of these instruments. 
 
 4. Only fresh milk should be brought to market, and it should 
 not be sold under the general denomination of "milk," but from 
 vessels marked clearly and in large letters, at a part easily seen, 
 stating their contents as : 
 
 "Whole milk. 
 
 Milk half creamed. 
 
 Skimmed milk. 
 
 6. Excluded from sale be all milk from cows sick with pulmo- 
 nary fever, anthrax, tuberculosis, and aphtha epizootica (hoof and 
 mouth disease), likewise, bitter, salty, mucous, abnormally col- 
 ored, spoiled or adulterated milk. 
 
 6. The greatest cleanliness shall be observed regarding the 
 vessels and measures for the milk, as well as the stores, which 
 must be airy, dry and cool, and which should in no wise be used 
 whereby the purity of the milk be endangered. It should never 
 be kept in places used for sleeping rooms. 
 
 7. Inspectors are entitled to take samples from all stores or 
 other places where milk is sold, against receipt or payment. 
 
 8. The inspection must always be done in the presence of at 
 least one witness, who must countersign the record. 
 
98 
 
 Propositions for Regulations Governing 
 Producers of Milk and Milk-Dealers. 
 
 The fanner should know what he brings to market. M. 
 Fleischmann says with reference to this : 
 
 " The farmer, whose intention it is to better himself by bring- 
 " ing his husbandry upon a rational basis, must know the value of 
 " his cows. To this end he requires aids which allow him, without 
 " being a scientist himself, to ascertain whether the milk of cer- 
 " tain cows be watery or rich in solids, and what the yield of 
 " cream is in special cases. He is more interested in comparing 
 " one milk Avith another, than in knowing the actual difference by 
 " percentage." 
 
 Considering this, it cannot be considered as asking too much if 
 it be required that farmers and dairymen should be held to regula- 
 tions as follows : 
 
 a. Strict supervision over the cattle, stables and feed. 
 
 h. Occasional examination of the milk of single cows, and the 
 yield of all mixed, with the aid of the lactodensimeter, Schatzmann's 
 cream test or lactobutyrometer. 
 
 c. Abnormal or spoiled milk shall not be sold. 
 
 d. Regularity in the time of milking must be observed. 
 
 e. The milk is to be properly cooled by putting the vessels 
 containing it in cold water, and stirring it slowly until it has 
 reached the temperature of the water. 
 
 f. The cooled milk must be kept in a cool place. 
 
 g. The farmer shall keep notes respecting number of cows and 
 daily yield of morning and evening milk. 
 
 Ti. ISTo milk drawn before the eighth day after calving shall be 
 brought to market. Likewise none from sick animals, or such 
 under medical treatment, or of cows which have to be watered 
 with unhealthy stagnant water. 
 
 i. The greatest cleanliness must be practiced during milking, 
 storing, or transporting the milk. 
 
Considering the consequences wrought by adulterated or other- 
 wise unhealthy milk, upon the health of consumers, it is certainly 
 not asking too much if, in the interests of humanity, exemplary 
 punishment for this crime is demanded, and that, especially, the 
 highest punishments which are possible under the law, be dealt 
 out to such persons, which have been held before for the same 
 offence. 
 
100 
 
 LIST OF APPARATUS AND CHEMICALS 
 
 REQUIRED FOR THE ANALYSIS OF 
 
 MILK AND INFANTS' MILK-FOODS. 
 
 Blue and red litmus paper, tunneric paper, distilled water, 
 absolute alcohol and ether. 
 
 Chemically pure hydrochloric, nitric, sulphuric and acetic 
 acids. 
 
 Sulphuric acid of commerce {Q&° B), and calcium fluoride in 
 powder, for cleaning platinum vessels. 
 
 Dilute sodium or potassiutn hydrate solution of known 
 strength, to neutralize the hydrochloric acid used for inversion. 
 
 Potassium hydrate solution of 1.048 specific gravity (50 potas- 
 sium hydrate and 1000 water), to neutralize Ritthausens' cupric sul- 
 phate solution. 
 
 Cupric sulphate solution (63.5 gi-ras. crystallized cupric sulphate 
 dissolved to 1 liter). 
 
 Fehling's solution (see page 28). 
 
 Uranium solution according to IS'eubauer, see Fresenius' Quan- 
 titative Analysis. 
 
 Iodine solution (1 iodine to 50 water). 
 
 JPhenolpJitalein as indicator in volumetric analysis. Dissolve 
 1 part in 30 parts of alcohol, and use from 1 to 2 drops at a time. 
 
 Potassium ferrocyanide soiution as a test for copper, in Feh- 
 ling's volumetric sugar determination. 
 
 Glazed paper, 
 
 Swedish filter paper, free from ashes, is obtained according 
 to P. T. Austen, by soaking for from 4 to 5 days the filters, 
 which had previously been washed with diluted hydrochloric acid, 
 in a mixture of 30 c.c. concentrated hydrochloric acid, 15 c.c. com- 
 mercial hydrofluoric acid, and 500 c.c. distilled water. The fluid 
 is then poured off, and the filters are washed with warm water 
 until no muriatic acid reaction is obtained. They are then dried. 
 The following manufacturers prepare paper free from ashes ; 
 Schleicher & Schuell, Darren, Prussia ; Linke and Rosala, Bruenn. 
 
 A fine chemical balance ?Ln^ >r ig^its. 
 
 Microscope, magnifying power to 400 or 500 linear dimension. 
 
 Thermometer (Celsius). 
 
 Specific gravity bottle tvith thermometer) Geissler, in Bonn, 
 Prussia. 
 
101 
 
 Platinum dishes and crucibles with covers and spatules. 
 Porcelain crucibles ivith cover, for the incineration of the 
 albuminate copper precipitate. 
 
 Glass cylinders with foot, of from 250 to 1000 c.c. contents. 
 
 Liter and 1-2 liter flasks. 
 
 Several nests of beaker glasses. 
 
 Several nests of porcelain dishes. 
 
 Glass flasks of from 50 to 500 c.c. contents. 
 
 Pipettes of from 5 to 50 c.c. contents divided into iV c.c. 
 
 Burettes, 50 c.c. contents, divided into tV c.c, with pinch cocks 
 or glass cocks, together with supports of wood or iron. 
 
 Wash-bottles for distilled water, alcohol and ether. 
 
 Large watch glasses, well fitting, and clamps to hold them. 
 They serve to hold the filters which are to be weighed. 
 
 Larger and smaller dessicators, with chloride of calcium or sul- 
 phuric acid. 
 
 Forceps of wood and of brass, platinum pointed. 
 
 Glass rods of various sizes and thickness. 
 
 Glass covers. 
 
 Feather brushes (black and stiff). 
 
 Rubber covered rods for removing precipitates. 
 
 Platinum or clay pipe stem, triangles. 
 
 Ring stands. 
 
 Muffle. 
 
 Water baths, with rings and covers. 
 
 Air bath, with thermometer and temperature regulator. 
 
 Water aspirator, 
 
 Liebig's coolers and stand. 
 
 Areometer, according to Tralles. 
 
 Lactodensimeter, with thermometers and glass cylinders. Manu- 
 factured by Alt, Eberhard and Jaeger, Ilmenau, Germany, or 
 Greiner and Friedrichs, Stuetzerbach. 
 
 Lactobutyrotneter, same manufacturers. 
 
 Schafzmann's cream tester, K. Schatzmann, Milch Versuchs- 
 station, Lausanne. 
 
 Gerber's apparatus for the determination of the fat, Greiner 
 and Friedrichs, Stuetzerbach, also Alt, Eberhardt and Jaeger, Il- 
 menau, Germany ; Freres Alvergniat, rue de la Sorbonne, Paris. 
 
 Gerber's set of apparatus for home use and milk inspection, in 
 case, as well as all other instruments used for milk testing, may be 
 obtained from the author. Correctness guaranteed. 
 
LEHN & FINK, 
 
 Wholesale Druggists, 
 
 IMPORTERS AND EXPORTERS, 
 
 No. 160 ^Villiam Street, 
 
 NEW YORK. 
 
 We call ttie attention of tlie Profession to onr 
 large and complete stock of strictly pure 
 
 CHEMICALS, 
 
 ACIDS, 
 
 METALS, 
 
 MINERALS, 
 ALCALOIDS, etc., etc., 
 constantljr imported direct from the most reliable 
 sources in Europe, in suitable original packages 
 to meet tlie "vvants of Laboratories, Manufacturers, 
 Colleges and Chemists in general. 
 
 RARE AND NEW ARTICLES A SPECIALTY. 
 
 Collections of Minerals, Alcaloids and Physio- 
 logical Preparations on band and imported to 
 order. 
 
 Quantity Supplies for Institutions, Schools, etc., 
 imported to order at special rates. 
 
 All orders will be executed witb utmost care 
 and promptness at lowest market prices. 
 
 LEHN & FINK, 
 
 P. O. Box 3 1 1 4, N. Y. 
 
Established 1850. 
 
 J.& H.BERGE, 
 
 Importers, Manufacturers and Dealers in 
 
 Chemical jiND PhysicjilJIpparjitus 
 
 — FOR — 
 
 CHEMISTS, ASSAYERS, COLLEGES, LABORATORIES, Etc. 
 
 Best Bohemian Glassware, 
 
 BEST GERMAN PORCELAIN AND GLASSWARE, 
 Crucibles of every descrij^tion. 
 
 Pure Chemicals and Reagents, 
 
 PLATINUM WIRE, FOIL, DISHES, CRUCIBLES, ETC 
 
 Improved Bunsen Burners, all styles, 
 Improved Bunsen Blast Lamps & Combustion Furnaces. 
 
 Furnaces, Blowpipes of all kinds ; Lamps, all kinds ; 
 
 Quevenne's Lactodensimeters, Lactobutyro- 
 
 METERS, and all other apparatus required 
 
 for the examination of Milk, 
 
 etc., etc., etc. 
 
 95 John Street, and 191 Greenwich Street, 
 
 p. o. Box 401. NEV/ YORK. 
 
 Apparatus of all kinds made to order and repaired in a superior 
 manner at moderate prices. 
 
This book is a preservation facsimile. 
 
 It is made in compliance with copyright law 
 
 and produced on acid-free archival 
 
 60# book weight paper 
 
 which meets the requirements of 
 
 ANSI/NISO Z39.48-1992 (permanence of paper) 
 
 Preservation facsimile printing and binding 
 
 by 
 
 Acme Bookbinding 
 
 Charlestown, Massachusetts 
 
 2004