mididi: GHIM C. iffliBEEf LIBRARY OF CONGRESS. UNITED STATES OF AMERICA. H ■^^■^■■9 T&i' I % s I ifc>;$ ■ ^H M ED1CAL C HEMISTRY > INCLUDING THE OUTLINES OF Organic §1 Physiological Chemistry. BASED IN PART UPON RICHES MANUAL DE CHIMIE. C. Gilbert Wheeler, Professor of Chemistry in the University of Chicago, and in the Hahnemann Medical College. 4 S. J. WHEELER, Chicago. 1879. I n ~ OTHER WORKS by PROF. WHEELER. DETERMINATIVE MINERALOGY. A practical guide to the recogni- tion of mineral species, chiefly by physical characteristics. Price $1.00. NATURAL HISTORY CHARTS. Five in number, one each of the fol- lowing: Mammalia; Birds; Reptiles and Fishes ; Invertebrates; Minerals, Rocks and Fossils. In all, over TOO illustrations. Wholly hand colored • Price of each chart, $7.00. The set, $30.00. NATURAL HISTORY PRIMER. A concise descriptive work on Zool- ogy aud Mineralogy. Price $1.00. CATALOGUS POLYGLOTTUS, Or classified list of the more important animals, minerals aud fossils in Latin, English, French, German and Spanish: for Scientific Travelers, Collectors, Curators of Museums and others. Price $2.00. IN PREPARATION. THE CHEMISTRY OF BUILDING MATERIALS. COPYRIGHT C. GILBERT WHEELER, 1878. CONTENTS. PAGE Introductory, - - = 7 Classification of Organic Compounds, 10 Homologous Series, - 12 Hydrocarbons, - - - 18 Alcohols, ~ 44 " Monatomic, - . - 46 " Diatomic, _ 58 " Triatomic, - = - 64 Ethers, - 69 Aldehyds, - - - 85 Acids, - 90 " MONATOMIC, . - - 96 w Polyatomic, - - 112 Alkaloids or Bases, - - - 127 " Artificial, - 132 i, 170 " Natural, - - - 137 Neutral Fatty Bodies, - 174 Sugars, - - - 181 Glycosides, _ 193 Vegetable Chemistry, - . - - 199 Cellulose, - - 205 Starch, - - - 210 Dextrin, - 214 Gums, - • - - - - 216 PAGE. Animal Chemistry, - 221 Albuminoids, - 225 Fibrin, - - - 231 Casein, .. 233 Digestion, - 236 Saliva, - 237 Gastric Juice, - 242 Bile, - 250 Pancreatic Juice, - 261 Chyle, Lymph, _ 270 Blood, - - 272 H^EMOGLOBULIN, • - 285 Chemical Pathology of the Blood, 294 Respiration, - 301 Animal Heat — Muscular Power, 316 Assimilation, - 321 Secretion — 'The Urine, - 333 Chemistry of Normal Urine, - 339 " " Abnormal " - 347 Urinary Sediments, - 352 " Calculi, = 353 Analysis of Urine, » 356 " " Urinary Deposits, - 364 " Calculi, - - 368 Sweat, - - - 370 Milk, « 376 The Soft Tissues, - 383 Osseous Tissue, - 396 Dental " . - 403 Exudations, - 407 PREFACE. Medical chemistry has not as yet secured in Ameri- can colleges sufficiently pronounced attention to create a demand for text-books of considerable size or ex- tended scope. In these simple Outlines, therefore, no more has been attempted than this circumstance would appear to warrant. It is hoped that the necessary conciseness in method and form of expression has not resulted in any important sacrifice of perspicuity in thought or arrangement. It would have been easier to prepare a larger work. From the bewildering wealth of results afforded by the labors of investigators in this branch of science, the ap- propriate selection of that suited to the wants of stu- dents was by no means an easy task. It is assumed in these Outlines that those entering upon the study of Medical Chemistry have previously made themselves acquainted with Inorganic Chemistry as taught by some recent author, such as Miller or Barker, or have at least become familiar with the gen- eral principles of modern chemical philosophy. The author taking this for granted, has not, therefore, en- cumbered the work with a restatement of that which appertains to the theory of chemistry in general. In addition to the organic portion of Eiche's Man- uel de Chimie, a translation of which by the author PREFACE. has served in part as basis for these Outlines, the works of Miller, Fownes, Williamson, Roscoe, and others have been freely used, while the chemical journals of Europe and America, including their latest numbers, have been consulted and the data which they aiforded utilized. "Where the excerpta have been from journals of too recent issue to be found in standard authors, a reference in brackets has been made to the original source. Of the three series of numbers thus employed, the first has reference to the list of journals given at the close of this work, the second usually refers to the number of the volume, though sometimes to the year, the third indicates the page. Lest any regard the number of characteristic re- actions of the more important compounds as insuffi- cient, it should be stated, that it was not within the plan of the author to adapt this work to the requirements of an analytical manual. Not more than two or three analytical tests are therefore given as a rule, and even this number only in the case of the leading compounds. A similar explanation might be proffered to any who may miss the full technical de- tails relative to certain compounds which are usually given in works on applied, or technological chemistry. Throughout the work, the centigrade thermometer and the metric system of weights and measures are employed, unless otherwise specifically stated. C. Gilbert Wheeler. University of Chicago, December, 1878. ORGANIC CHEMISTRY. LNTKODUCTOKY. Organic chemistry is the science of the compounds of carbon. Only a small number of other elements are met with in natural organic substances; they are hydrogen, oxygen and nitrogen, sometimes also, sulphur, phos- phorus, and very rarely certain other elements. Chemists have succeeded in incorporating most of the elemental substances in organic bodies, yet the larger number even of the artificial compounds include only the four elements first named. Paraifine is found by analysis to contain only carbon and hydrogen, and is therefore called a hydrogen- carbide. The hydrocarbides are compounds so stable and fundamental that some chemists, as Schorlemmer for instance, have even defined organic chemistry as " the chemistry of hydrocarbons and their derivatives." From alcohol, or sugar, we may obtain carbon and water. These bodies therefore are composed of three elements : carbon, hydrogen and oxygen, and are called carbohydrates ; though by some chemists, this term is restricted to those compounds containing car- 8 ORGANIC CHEMISTRY. bon with hydrogen, and oxygen in such proportions as would form water. If albumen is decomposed by heat, the result is not only carbon and water, but also ammonia ; this sub- stance accordingly is nitrogenous. The number of organic bodies is very great. As they are composed of a small number of elements only, it may be concluded that the latter unite in a very great variety of proportions ; it is therefore of much impor- tance to know the molecular grouping of these ele- ments. The mere fact that the kind and number of elements entering into a compound are known, is not sufficient proof that its molecular structure is really determined. Synthesis must often be employed to confirm the results of analysis. Berthelot has specially occupied himself with the synthesis of organic bodies, and has artificially produced a great number of them. Other chemists have experimented in the same direction during the last 15 or 20 years. However, Gerhard t's opinion advanced in 1854; viz., " The vital force alone operates by syn- thesis and reconstructs the edifice demolished by chemical affinity," has ceased to be held as true. ISOMERISM. Carbon, hydrogen, oxygen and nitrogen are not only capable of uniting in a great variety of proportions, but these elements also furnish numerous isomeric bodies ; these comprise substances which, while com- ISOMERISM. y posed of the same elements, have different properties. Sometimes the physical properties alone are different ; we then have physical isomerism. When the chemical properties themselves are modi- fied, this is denominated chemical isomerism. Of the latter, two kinds are recognized. I. Polymerism / cyanogen and paracyanogen are examples of this variety of isomerism ; the latter is to be considered as cyanogen, GN condensed, thns (CN)n ; it is a polymeride of cyanogen. The weight of the molecule of these two substances is therefore dif- ferent. II. Metamerism. At other times the isomerism results from a different grouping of elements in the compound, the molecular weight remaining the same. We will illustrate this by two examples : a) Methyl acetate, aud b) Ethyl formiate. Acetic acid = H-0-C 3 H 3 0. Methyl hydrate, or methyl alcohol=H-0-CH 3 . When these two bodies react they furnish water and methyl acetate, CH 3 -0-C 2 H 3 0==C 3 H 6 2 . Formic acid=H-0-CHQ. Ethyl hydrate, or ethyl alcohol=H-0-C 2 H 5 . JNow formic acid contains CH 2 less than acetic acid, and hydrate of ethyl contains one molecule of OH 2 more than does hydrate of methyl. As these substan- ces in reacting lose one molecule of water, it is there- fore clear that the compound obtained will have, like the preceding one, the formula C 3 H 6 3 . But these 10 ORGANIC CHEMISTRY. two products are not identical substances, for the for- mer treated with alkalies regains the molecule of water which it had lost, reforming acetic acid and methyl hy- drate, while the latter regenerates formic acid and ethyl hydrate. These bodies accordingly differ in the arrangement of their molecule ; they are called metameric bodies. Finally there exist bodies which are isomeric, prop- erly so-called, possessing the same formula, having the same general reactions, the same chemical functions, and which differ only in a very few, chiefly physical, properties : such are oil of turpentine and oil of lemon, each having the formula C 10 H 16 . CLASSIFICATION OF ORGANIC COM- POUNDS. Chemical Types. — The idea of referring organic bod- ies to some simple model, or type, was originally work- ed out by Laurent and Gerhardt, 1846-53. though the germs of their ideas on classification are to be found in the earlier papers of the distinguished American chemist T. S terry Hunt. (Am. Jour. Sci. [2] xxxi.) The four principal types are : H' ) I. The hydrogen type, -p-, VorH 2 . II. The oxide or water type, tt' [ O' ' orH 2 0. H'j III. The nitride or ammonia type,H ' \ N ' ' ' or H 3 N. ORGANIC TYPES. 11 H' TT / IV. The marsh gas type tt t H' VC 1Y orELC. Of the leading groups of organic bodies, we refer to the hydrogen type: hydrocarbides, aldehyds and the compounds of metals and metalloids with organic radicals. To the water type are referred the alcohols, ethers, mercaptans and anhydrides. To the ammonia type belong the amides, amines, and alkalamides, all of which are denominated com- pound ammonias. Marsh-gas is the type to which carbon dioxide is referred, as well as some of the more complex organo- metallic bodies. Further details as to the relation of each of these classes of compounds to their respective types will be given as each particular class is studied. Besides the simple type, Kekule has proposed com- pound types formed by the combination of two of the four types already given. Thus the types of ammonia and water combined serve as a pattern for carbamic and oxamic acids: JJ ' "\ Carbamic acid. Oxamic Acid. S "'"■ i}>, IK g: o- %\o < c '% o 12 ORGANIC CHEMISTRY, HOMOLOGOUS SERIES. The members of a series of compounds which have the common difference of CIT 3 are said to be homolo- gous. Two or more such homologous series are termed isologous. The first idea of progressive series in organic chemistry was enunciated by James Schiel, of St. Louis, Mo., in 1842. It was afterwards adopted by Gerhardt unchanged, save only in name. (100-5-195.) The subjoined table will illustrate the nature of these series. Each vertical column forms a homologous series in which the terms differ by CH 2 , and each hori- zontal line an isologous series in which the successive terms differ by H 2 . The bodies of these last series are designated as the monocarbon, dicarbon group, etc. C H 4 C H 3 C 2 H 6 C 2 H 4 C 2 H 3 ^3^8 C 3 H 6 C 3 H 4 C 3 H 3 C 4 H 10 C 4 H 8 C 4 H 6 C 4 H 4 C 4 H 3 C 5 H 12 C 5 H 10 C 5 H 8 C 5 H 6 C 5 H 4 C 5 H< C 6 H 14 C 6 H 12 C 6 H 1C i C 6 H 8 C 6 H 6 C 6 H The terms of the same homologous series resemble one another in many respects, exhibiting similar trans- formations under the action of given re-agents, and a regular gradation of properties from the lowest to the highest ; thus, of the hydro-carbons, C n H 2n42j the low- est terms CH 4i C 2 H 6i and C 3 H 8i are gaseous at ordinary temperatures, the highest containing 20 or more car- HOMOLOGOUS SERIES. 13 bon-atoms, are solid, while the intermediate com- pounds are liquids, becoming more and more viscid and less volatile, as they contain a greater number of car- bon-atoms, and exhibiting a constant rise of about 20° C. (36° F-) in their boiling points for each addition of CH 2 to the molecule. The individual series are given in the following ta- ble, witb the names proposed for them by A. W. Hoffmann: Methane Methene CH 4 CH 2 Ethane Ethene Ethine C 2 H 6 C 2 H 4 C 2 H 2 Propane Propene Propine Propone C 3 H 8 C 3 H 6 C 3 H 4 C 3 H 2 Quartane Q uar ten e Quartine Quartone Quartune C 4 H 10 C 4 H 8 C 4 H 6 C4Q.4 4 XX 2 Quintane Quintene Quintine Quintone Quintune 5 H I2 C 5 H 10 C 5 H 8 C 5 H 6 C5H4 Sextane Sextene Sextine Sextone Sexto ne ^6-t44 C 6 H 12 C 6 H 10 C 6 H 8 C 6 H 6 The formula in the preceding tables represent hydro- carbons all of which are capable of existing in the separate state, and many of which have been actually obtained. They are all derived from saturated mole- cules, C n H 2n+2i by abstraction of one or more pairs of hydrogen- atoms. But a saturated hydrocarbon, CH 4i for example, may 14 ORGANIC CHEMISTRY. give up 1, 2, 3, or any number of hydrogen-atoms in exchange for other elements ; thus marsh gas, CH 4i subjected to the action of chlorine under various cir- cumstances, yields the substitution-products, CHaOl, CH 2 C1 2 , CHC1 3 , CC1 4 , which may be regarded as compounds of chlorine with the radicles, (CH 3 )', (CH 2 )", (CH)'", C»; and in like manner each hydrocarbon of the series, C n H 2n+2 , uiay yield a series of radicles of the forms, (QAm)', (CH*)", (C„H„)'" (C n H 2n _ 2 )*&c. each of which has an equivalent value, or combining power, corresponding with the number of hydrogen- atoms abstracted from the original hydrocarbon. Those of even equivalence contain even numbers of hydro- gen-atoms, and are identical in composition with those in the table above given ; but those of uneven equiva- lence contain odd numbers of hydrogen-atoms, and are incapable of existing in the separate state, except, perhaps, as double molecules. These hydrocarbon radicles of uneven equivalence are designated by Hoffmann, with names ending in yl, those of the univalent radicles being formed from methane, ethane, &c, by changing the termination HOMOLOGOUS SERIES. 15 ane into yl ; those of the trivalent radicles by chang- ing the final e in the names of the bivalent radicles, methene, &c. , into yl; and similarly for the rest. The names of the whole series will therefore be as follows : CH 4 (OH 3 )' (CH 2 )" (OH)'" Methane Methyl Methene Methenyl C,H 6 (W (C 2 H 4 )" (C 2 H 3 )'" Ethane Ethyl Ethene Ethenyl C 3 H 8 (C 3 H 7 )' (C 3 H 6 )" (e 3 H 5 )'" Propane Propyl Propene Propenyl &c. &c. &c. From these hydrocarbon radicles, others of the same degree of equivalence may be derived by partial or. total replacement of the hydrogen by other elements, or compound radicles. Thus from propyl, C 3 H 7 , may be derived the following univalent radicles : — C 3 H 6 01 3 H S 01 4 8 H 5 Chloropropvl Tetrachloropropyl Oxypropyl c 3 h 2 ci 3 6 c 3 H 6 ((m) - c 3 H 6 (]sro 2 ) Trichloroxy propyl Cyanopropyl. Mtropropyl C 3 H 4 (^TH 2 )0 C 3 H 6 (CH 3 ) . C 3 H 3 (C 2 H 5 ) 2 Amidoxypropyl Methylpropyl Diethylpropyl. From the radicles above mentioned, all well-defined organic compounds may be supposed to be formed by combination and substitution, each radicle entering into combination, just like an elementary body of the same degree of equivalence. 16 ORGANIC CHEMISTRY. TABLE TO ILLUSTRATE THE ARRANGEMENT OF THE MORE Series. Hydro- carbons. Sulphides. Chlorides or Haloid Ethers. Alcohols. General Formula. CriRzn CreH2«+i | q CnB.2Ji+i f & CrcH2W+iCl CriH.211+1 \q i. C H2 2. C2 H4 3. C 3 H 6 4. C 4 H 8 5. C5 Hio • 6. C 6 H12 7. C7 H14 8. Cg H16 9. C 9 H18 10. C10H20 (C H 3 )2S (C2Hs)2S (C5Hn)2S C H3 CI C2H5 CI C3H7 CI C4H9 CI C5HIIC1 C8HI7C1 C H3 HO C2H5 HO C3H7 HO C4H9 HO C5H11HO C 6 Hi 3 HO CSH17HO Types §} g}0 Hf l\° OEGANIC COMPOUNDS. 1? IMPORTANT ORGANIC COMPOUNDS IN HOMOLOGOUS SERIES. Mercaptans. Aldehyds. Acids. Simple Ethers. Compound Ethers. CnB.2n+i | c H f S CWH271-1 O ) h r C;zH2«-iO ) C?lH27l+I } n CwH2w+if u CwH2n+i J n Cn,B.2n-iOS C H3 HS C H 0,H HC H O2 (C H 3 )20 C H3 C H O2 1. C2H5 HS C2 H3 0,H HC2 H3 O2 (C2Hs)20 C2HS C2 H3 O2 2. C3 H5 0,H HC3 H5 O2 C2HS C3 H S O2 3. C4H9HS C4 H7 0,H HC4 H7 O2 C2HS C4 H7 O2 4. CsHnHS C5 H9 O.H HC5 H9 Os (C 5 Hii) 2 CSH11C5 H9 O2 5. C6 HnO,H HC 6 H11O2 C2HS C 6 H11O2 6. C7 Hi30,H HC7 H13O2 HC 8 H15O2 HC9 H17O2 C8H5 C7 H13O2 7. C2H5 Cg H1SO2 8. C2H5 C9 H17O2 9. CioHi9H,0 HC10H19O2 (CioH2i)30 C2H5 C10H19O2 10. g[o H i i}o Hf° Ih 18 OBGANIC CHEMISTRY. CAKBIDES OF HYDEOGEK Tlie origin or preparation of these compounds, also called hydrocarbides, and their properties, physical and chemical, all differ largely. They are unlike the hydrogen combinations studied in inorganic chemistry inasmuch as they possess but feeble chemical energy Among the carbides are: acetylene, marsh-gas or methane, ethylene, oil of tur_ pentine and of lemon, benzol, naphthalin, petroleum, caoutchouc, gutta-percha, etc. The hydrocarbides will be divided into six series, they are all built upon the type of a molecule of hy- drogen, or H' ) w\- FIBST SEEIES. General Formula, CnH2 n — g. ACETYLENE, OR DIHYDROGEN DICARBIDE. Discovered by Davy and composition determined by Berthelot. Formula, C2H2. Specific Gravity, 0.92. Density, 13. Molecular weight, 26. Direct combination of Carbon and Hydrogen. Up to comparatively recent times it has been con- sidered impossible to unite earbon and hydrogen di- rectly. Berthelot, however, succeeded in doing this in the year 1863. Preparation. — The apparatus which he employed CAEBIDES OF HYDKOGEJS. 19 in this remarkable synthesis, consisted of a glass flask, provided with two lateral tubulures through which passed two metallic rods, terminating in carbon points, and which approached so as to form, when connected with a powerful battery, an electric arc. The corks through which these rods passed were provided with another opening each, to which a tube was adapted. Through one of these tubes hydrogen was admitted and through the other the products of the reaction passed as they were formed. The gas was collected in a solution of cuprous chloride in ammonia. A red-precipitate, acetylide of copper was formed, which was thrown upon a filter and treated with hydrochloric acid in a flask, whereupon acetylene was set free. Many organic compounds produce acetylene on subjecting their vapors to the action of electric dis- charges. Acetylene is also produced, as a rule, whenever or- ganic matter is decomposed by heat. Peopeeties. — Acetylene is a colorless gas, having a disagreeable odor. It is moderately soluble in water, and is difficultly liquified. It is decomposed, at about the temperature at which glass melts, into carbon, hydrogen, ethylene, ethyl hydride and condensed hydrocarbides, among which Berthelot has found ben- zol. Thenard has recently obtained it both as a liquid and a vitreous solid. (9 — 78 — 219.) Acetylene burns with a fuliginous flame. It de- tonates violently and without residue when mixed with 20 ORGANIC CHEMISTRY. 2.5 volumes of oxygen. Cuprous acetylide is an ex- plosive body. It is sometimes formed in brass gas- pipes, and has been the cause of fatal accidents. Chlorine acts upon acetylene with extreme energy; there is often detonation accompanied by light. On moderating the action the compound C 2 H 2 C1 2 can be obtained, which, as well as the body C 2 H 2 C1 4 , can also be prepared by the action of antimonic chlo- ride upon acetylene. As acetylene is not uncommonly studied in con- nection with inorganic compounds, a more detailed ac- count of this hydrocarbide need not be given here. Acetylene is the prototype of a homologous series of hydrocarbides, of which the general formula is, C n H 2n _ 2# The following members of this series are known: Allylene, - - - - C 3 H 4 Crotonylene, - - - C 4 H 6 Valerylene, - - - C 5 H 8 Rutylene, - C 10 H t8 Benzylene, - C 15 H 38 . ETHYLENE. 21 SECOND SEEIES. General formula, C n H2n. ETHYLENE. Synonyms: Elayl, Olefiant gas. Formula C 3 H 4 . Sp. Gr. 0.97. Molecular weight, 28. This gas, for no good reason other than custom, is always studied in inorganic chemistry, usually in con- nection" with the consideration of illuminating gas, of which, with methane, it forms a prominent constit- uent. Ethylene is the type of a class of homologous hydro- carbides, of which the general formula is : Each member of the series is related to an alcohol from which it may be obtained on treatment with bodies having a great affinity for water, as sulphuric acid or zinc chloride. C n H 2n+2 + 2 — H 2 = C n H 3n . 22 ORGANIC CHEMISTRY. We note the following members of this series Ethylene, - - - C 2 H 4 Propylene, _ C 3 H 6 JButylene, - - - C 4 H 8 Amylene, - C 5 H 10 Hexylene, - - C 6 H 12 Heptylene, - C, H 14 Octylene, - - - C 8 H 16 Nonylene, - C 9 Hl8 Paramylene, - - C 10 H 30 Cetene, - - CiiH 33 Duodecylene, - 12 H 24 Tridecylene, (Paraffin?)* ^13^26 Tetradecylene, - C 14 H 28 . *A. (x. Pouchet(66— [3] 4 — 868) lias prepared from paraffin, by oxydation with nitric acid, paraffin acid, C24H43O2, from which he deduces C24H50 as the formula for paraffin. METHANE. 23 THIKD SEEIES. General formula, C n H-an+a* METHANE. Discovered by Volta in 1778. Synonyms; Methyl hydride, Marsh gas, Formene. Formula CH 4 or CH 3 , H. Sp. Gr. 0.559. Molecular weight, 16. Permanent gas, not liquifiable, neutral. Not discussed in detail here for the same reasons as given under Ethylene. Methane is the first member of the following very important homologous series : C H 4 methyl hydride, or methane. C 2 H 6 ethyl a " ethane. C 3 H 8 propyl a " propane. C 4 H 10 butyl a " butane. C 5 H 12 amyl a " amane. C 6 H 14 hexyl a " hexane. C 7 H 16 heptyl a " heptane. C 8 H 18 octyl « " octane. G9H20 nonyl a " nonane. ^ioH-22 decyl u " decane. C11H24 undecyl a " undecane. C^H^ bidecyl u " bidecane. 24 OEGANIC CHEMISTRY. a tridecane. " tetradecane. " pentadecane. " hexadecane. C 13 H28 trideeyl " C^Hgo tetradecyl " C 15 H32 pentadecyl " C 16 R M hexadecyl " Nearly all the members of this series have been found in American petroleum, mixed with members of the preceding, or ethylene, series. Crude petroleum, refined by fractional distillation, is still a mixture of various hydrocarbons. The commercial names given to the products sep- arated at the different boiling points, do not appertain to chemical compounds, or bodies having a definite composition. Subjoined is a table based on Dr. C. F. Chandler's Eeport on Petroleum, (100 — '72-41) showing the PKODUCTS OF THE DISTILLATION OF CRUDE PETROLEUM.* NAME. O a a 3 si Pm 2! pq CHIEF USES. Cymogene . . IK , 4 55 19% .625 .665 .706 .724 .742 .804 .847 .833 Solid. 0°C. 18.3 48.8 82.2 104. 4 148.8 176.6 218.3 301.6 j Generally nncondensed — used in j ice machines. j Condensed by ice and salt— used as \ an anaesthetic. Used in making "air-gas. " ( Used for oil-cloths, cleaning, adul- •< terating kerosene, etc. For paints ( and varnishes, Used to adulterate kerosene oil. C Naphtha B Naphtha.., A Naphtha Kerosene oil Mineral sperm Lubricating oil Paraffin Ordinary oil for lamps. Lubricating machinery. *Re-arrangedfrom Dr. C. F. Chandler's Report on Petroleum, presented to the Board of Health, of the City of New York, 1870. METHANE. 25 UNSAFE KEROSENE. Many accidents occur by explosion of lamps, when kerosene oil contains too much of the lighter oils, ben- zine and naphtha. This makes the oil too readily in- flammable, for the lighter oils are driven out by heat- ing (as when a lamp or kerosene stove is burning), and their vapors mixed with the oxygen of the air form a dangerous explosive mixture. There is a law requir- ing manufacturers to keep kerosene oil free from these lighter oils, unfortunately not always faithfully en- forced. The temperature at which kerosene, on heating in an open vessel, emits vapors which readily catch fire on approaching a burning body, is called, technically, the "flash point/' and that at which the kerosene itself inflames is called the "burning point." FOSSIL RESINS, AND BITUMEN. These substances include amber, retinasphalt, as- phalt, retinite, and many other allied bodies which are chiefly contained in the tertiary strata. In many in- stances they are the products of the action of an ele- vated temperature upon vegetable bodies; and when this is the case, they form irregular deposits which im- pregnate the strata around. In many cases the bitu- mens occur in regular beds, which appear to have been formed in a manner similar to the deposits of true coal. Certain important building stones have been found to be more or less impregnated with bitumen. Such is the limestone obtained at the artesian well 26 ORGANIC CHEMISTRY. quarry in the city of Chicago, and the celebrated Buena Yista, (Ohio,) sandstone used extensively in Cincinnati; also employed at Chicago in various prominent public buildings, as the post-office and Chamber of Commerce. The author, in making a chemical examination of the latter stone for the United States Treasury Department, found it to con- tain 2.3 per cent, bituminous matter. BENZOL. 27 FOUETH SEKIES. General formula C n H2n-6. BENZOL. Synonyms ; Benzene, Benzine. Formula C6H 6 . Sp. Gr. 0.88. Molecular weight, 78. Sp. Gr. of vapor 2.70. Density" " 39. Solid at 4°. Boils at 80.5°. Benzol is obtained, with acetylene and ethylene, in the decomposition of organic substances by heat, and its production is especially favored when the temperature is kept at a high point for some time. Ethylene and methane form at a tolerably low temperature. Acetylene, which is richer in carbon, is produced at a higher temperature. Benzol and especially napthalin, being still more carbonaceous, are formed at an extremely high temperature. Berthelot has prepared benzol synthetically by con- ducting methane tribromide, CHBr 3 , over red-hot copper : 6(CHBr 3 )+9Cu=C 6 H 6 +9CuBr 2 . Benzol may be considered as condensed acetylene: C 6 H 6 =(C 2 Ha) 3 . 28 ORGANIC CHEMISTRY. Originally, benzol was prepared by a process analo- gous to that which furnishes methane, i. e., by distill- ing benzoic acid with lime, C 7 H 6 3 +CaO = Ca C O s +C 6 H 6 . At present it is obtained in immense quantities from the tar which is formed as an accessory product in the manufacture of illuminating gas. At the high temperature of the gas-retort other pro- ducts, homologous with benzol, are formed as well; viz.: Toluene C 7 H 8 boils at 110° Xylene ^8 H t0 u ic 139 o Cumene C 9 H 12 " " 165° Cymene C10H14 " " 180° and other hydrocarbides, as napthalin C 10 H 8 , anthra- cene, also various sulphur compounds, notably carbon bisulphide; several oxygenated compounds, as phenol C 6 H 6 0, cresylol C^H 8 ; nitrogenous compounds, as aniline C 6 H 7 N, and various members of its homologous series. Benzol is a colorless, neutral liquid, with a specific gravity of 0.89, almost insoluble in water but soluble in alcohol and ether. It dissolves sulphur, phosphorus, iodine, the differ- ent resins, and fatty substances ; this latter property causes it to be employed similarly with commercial " benzine' ' for cleansing purposes. Care must be taken to rub with a piece of cloth having an open texture, BENZOL. 29 that it may remove the benzol by absorption, without which the spot would reappear after evaporation of the solvent. Benzol burns with a fuliginous flame. Nascent oxygen gives with it various products, and notably oxalic acid and carbon dioxide. Chlorine and bromine yield crystalline compounds with benzol. Benzol is the simplest member of a group of bodies known as the aromatic compounds, of which we shall proceed to describe some of the more important. For distinguishing benzol from the benzine of com- merce, which is made from petroleum, Brandberg recommends to place a small piece of pitch in a test tube, and pour over it some of the substance to be ex- amined. Benzol will immediately dissolve the pitch to a tar-like mass, while benzine will scarcely be col- ored. Nitro-benzol C 6 H 5 ]Sr0 2 . This body is obtained by treating benzol with fuming nitric acid. 6 H 6 +HN0 3 = C 6 H 5 (N0 2 )+H 2 0. Nitro-benzol is a yellowish oil, crystallizing at 37°, has a sweet taste and an odor which has led to its use in perfumery under the name of essence of mirbane. Taken internally it acts as a poison. On treatment of nitro-benzol with nascent hydrogen, hydrogen sulphide, or other reducing agent, we obtain 30 ORGANIC CHEMISTRY. aniline, which is a colorless liquid, boiling at 182°. It does not act upon litmus, yet combines with the acids, forming crystallizable compounds. Aniline gives with chlorine, bromine and nitric acid products of substitution which are very numerous and well denned. It reacts upon the iodides of methyl, ethyl, etc., forming the corresponding amines, or bodies constructed on the type of ammonia, having one or more of the hydrogen atoms replaced by an organic compound radicle: C„H 5 Aniline C 6 H 7 JSr = N" { H Methylaniline C 7 H 9 lSr = N \ CH* ! Cells CH 3 . C 2 H 5 C 6 H 5 or, when free, (C 6 H 5 ) 2 , is the radicle phenyl, hence aniline is properly phenylamine. Aniline has, during the last score of years, acquired great importance, as, under the influence of oxydizing bodies, it forms most remarkable tinctorial com- pounds. If a small quantity of aniline is added to a solution of chloride of lime, the liquid is colored violet, which color disappears in a few moments. In 1858, Perkins obtained, by the action of potassium bichromate and sulphuric acid, a beautiful purple, which is known in BENZOL. 31 commerce as mauve. Shortly after, Yerguin obtained a magnificent red coloring matter on heating aniline with tin dichloride. This substance, known under the names of aniline- red, fuchsin, magenta, etc., is now very economi- cally obtained with arsenic oxide in place of the tin dichloride, which is reduced to arsenous oxide by the reaction. Hoffmann has shown that aniline-red is a* salt of a colorless base, which he calls rosaniline; this substance has the formula C20H21N3O, or CaoH 19 N3,H 2 0. In the past few years there have been produced green, yellow and black colors, all originating from aniline. These substances dissolve in alcohol, and dye wool and silk without in any way weakening the fabric. They have a magnificent lustre, but their permanency is rot of the highest grade. The consumption of aniline for dyeing has now come to something enormous, amounting in Germany alone to over 15,000 tons per annum. The aniline colors are employed in injecting tissues for microscopic preparations. For a fuller account of the aniline colors, a larger work should be consulted. The history of aniline affords one of the most re- markable instances of the value of scientific chemical research, when perseveringly and skillfully applied, for at first few substances seemed to promise less; and the gigantic manufacturing industry at present connected with this compound, in its applications as a 32 ORGANIC CHEMISTRY. tinctorial agent, offers a singular contrast to the earlj experiments upon this body, when a few ounces fur- nished a supply which exceeded the most sanguine ex- pectations of the early discoverers of this body. Phenol, C 6 H 6 0. Synonyms: Hydrate-of phenyl, carbolic acid or phenic acid. It occurs in castoreum, though usually procured from the portions of coal-tar distilling over between 170° and 195°. They are agitated with caustic soda, water added to separate the insoluble oils, and the phenol dissolved in the alkali is liberated as a crys- talline mass, on decomposing the potassium compound with hydrochloric acid. Salicylic acid, distilled with an excess of lime, also furnishes phenol; C 7 H 6 3 + CaO = CaC0 3 + C^O. Ifphenyl-sulphuricacid, V 5 > S0 4 , obtained by di- rect action of sulphuric acid uj>on phenol, is heated with potassium hydrate to about 300 ° , potassic phenol CglLsKO is obtained. Phenol is therefore obtained from benzol under the same conditions as alcohol is obtained from ethylene, the corresponding hydro- carbide. Phenol crystallizes in handsome needles, fusible at 34° and boiling at 188°. It is little soluble in water, PHENOL. 33 very soluble in alcohol and ether. Phenol furnishes with chlorine, bromine and iodine numerous substitu- tion products. Phenol has come, like alcohol, to have a generic signification, there being a number of analogous com- pounds, though only this, the ordinary phenol, is an important body. Heated with concentrated nitric acid, it furnishes yellow, very bitter, crystals of the body known as Picric or Carb azotic acid. Picric acid is also formed when silk, benzoin, aloes, indigo, etc., are treated with nitric acid. This acid is very largely used in dyeing, either di- rectly to produce a yellow color, or, combined with in- digo, to produce a green. Phenol, though called carbolic acid, does not decom- pose the carbonates, or combine with the metals to form true salts. Phenol dissolves in sulphuric acid without coloration, if pure, and forms phenyl-sulphuric acid or sulpho-carbolic acid ° 6 l 5 }so 4! which gives definite salts with the metals. One of these, the phenyl- sulphate or sulpho-carbolate of so- dium NaC 6 H 6 S0 4 , is claimed to have valuable proper- ties as a prophylactic against scarlet fever. Phenol gives certain reactions of the alcohols ; this 34 ORGANIC CHEMISTRY. somewhat explains the origin of the name given it by Berthelot. This "body is the type of a class of com- pounds which contains: Cresylol obtained from creosote C? H 8 O Phlorylol s < " " . C 8 H 10 O Thymol " " essence of thyme Ci H 14 O. PHYSIOLOGICAL ACTION OF PHENOL. Phenol attacks the skin, producing a white stain. It coagulates albumen and is employed with great success as an antiseptic and disinfectant. It is used externally in a diluted state to dress wounds which suppurate, also in many surgical cases. It is sometimes used internally. Large doses of it are poisonous. Carbonate and especially saccharate of calcium are considered as antidotes for phenol. Grace Calvert has announced that olive or almond oil is a still better antidote. OIL OF TUKPENTINE. 85 FIFTH SEKIES. General Formula, C n H2n— 4. ESSENCE, OK OIL OF TURPENTINE. Formula C10H16. Density of vapor compared with air 4.7. Molecular weight, 136. Boils at 160° Turpentine is extracted from several varieties of the family of Conifer^ notably from the pine, fir and larch. The products vary somewhat with the nature of the tree, but they have many common characteristics; their composition is the same, their density is nearly identical and their boiling point very nearly so. Their rotary action on the solar ray varies largely. Isomeric carbides are found in other families of plants, in the aurantiacece family for instance, as the lemons and oranges. These contain carbides very dif- ferent, as evidenced by their odors and other physical properties, also different in certain chemical relations, yet having the same composition as oil of turpentine. There are also various polymers of this carbide. This entire series of hydrocarbons can be divided into three groups. The first contains carbides having 36 ORGANIC CHEMISTRY. the formula C 10 H 16 , their boiling points being below 200°, and including : Density. Boiling at Oil' of turpentine, .0.86 157° to -160°. " cloves, 0.92 140° " 145°. " lemon, 0.85 170° " 175°. u orange, 0.83 175° " 180°. " juniper, 0.84 about 160°. " bergamot, 0.85 " 183°. " P e PP er > 0.86 " 167°. " elemi, 0.85 " 180°. The carbides of the second group have the formula C^H^ their boiling point is above 200°, they are: Oil of copaiva, 0.91 245°. " cubebs, 0.93 240°. The third group contains the non- volatile carbides, such as Density Caoutchouc, - 0.92. Gutta-percha, - - - 0.98. The rotary power, constant for each, varies with the different species. French oil of turpentine causes the plane of polar- ization to deviate to the left; the American variety turns it 13° to the right; oil of lemon causes a devia- tion of 50° to the right; in the case of essence of elemi the deviation amounts to 100°. Some of the OIL OF TURPENTINE. 37 essential oils of the first group contain oxygen com- pounds as well as the carbohjdrides. The principal chemical differences between the members of the group are the facility with which they are oxydized and their reaction with hydrochloric acid. Essence of turpentine becomes resinous rapidly when exposed to the air and finally solidifies. Es- sence of lemon becomes viscid after a considerable time. Hydrochloric acid produces, with essence of turpentine, a liquid and a solid compound, having each the same composition, O 10 H 16 , HC1, which, after a few weeks, becomes a dichlorhydride, (by some denomi- nated a dichlorhydrate), C 10 H 16 ,2HC1. Essence of lemon also gives two dichlorhydrides at once, one liquid, the other solid. Oil of turpentine may be obtained in a pure state, on distilling the commercial article in a vacuum. Thus obtained, turpentine is colorlesSj limpid, very volatile, and has a characteristic odor. It is insoluble in water; very soluble in alcohol and ether. It burns with a smoky flame; on exposure to the air it oxydizes and becomes resinous. The same effect is produced more rapidly with oxide of lead and some other ox- ides which render the oil siccative and suitable for use in painting. J. M. Merrick (100-4-289) has noticed the circumstance, important in its technical applica- tions, that oil of turpentine attacks metallic lead quite strongly; tin, on the other hand, not at all. Turpen- tine, if exposed to the air, mixed with a solution of indigo, absorbs oxygen and transfers it to the indigo, 38 ORGANIC CHEMISTRY. which loses its color, yielding a product of oxydation called isatin. Under these circumstances, the turpen- tine does not change, and a given quantity of the es- sence can absorb several hundred times its volume of oxygen, and oxydize an indefinite quantity of indigo. This oxygen is probably the active modification, or ozone. Heated to 300° in a hermetically sealed tube, it changes into two products, one, isomeric, called iso- turjpentine, which boils at 177°, and which exerts a rotatory power of 10° to 15° to the left; the other, a polymer called onetartereberithene^ C20H32 boiling at 360°. OTHER SERIES OF HYDROCARBIDES. Cinnamene C 8 H 8 is a very refractive liquid with a density of 0.924, boiling at 146°. Styrol which is produced from storax is converted at 205°, into a polymeric solid, termed Meta-styrol or Draconyl. If styrol is made to act upon acetylene, or ethylene, at a red heat, there is obtained the very important hydro- carbide naphthalin Ci H 8 . This is a body crystalliz- able in very handsome plates, and is ordinarily obtained from coal tar by distillation between 200° and 300°; heavy oils pass over, out of which naphtha- lin crystallizes; on cooling, the mass is pressed and purified by sublimation. It fuses at 79° and distils at 220°. Naphthalin is associated in coal tar with a hydro- carbide, beautifully crystallizing in long needles, fus- ing at 93° and boiling at 285°. This is acenaphtene ALIZARIN. 39 C 12 H 10 . Another hydrocarbide is also found in this tar, anthracene. Its formula is O 14 H 10 . It forms very diminutive crystalline plates fusing at 210° and boil- ing at 360°. Its vapOr is extremely acrid. This body has recently enabled chemists to repro- duce the coloring principle of madder; alizarin C I4 H 8 4 . It is obtained on oxydizing anthracene by means of a mixture of bichromate of potassium and sulphuric acid, which." gives oxy anthracene C 14 H 8 2 . This, with fused potassa, furnishes a combination of potassium and alizarin, from which the latter is pre- cipitated by an acid. It has the form of brilliant bronze-colored needles, identical with natural alizarin obtained from madder. Alizarin sublimes at 215° and is very stable, little soluble in cold water, but readily soluble in boiling water. It is easily dissolved in alcohol, ether, and car- bon bisulphide. Its chemical character, not quite well defined as yet, appears to place it among the phenols. (See page 33.) The artificial production of alizarin from anthra- cene, thus furnishing a cheap substitute for madder, the chief dye-stuff used in printing calicoes, is one of the latest and most noteworthy triumphs of organic chemistry. Thousands of acres of land in Europe, especially in Alsatia, now devoted to the culture of madder, may be restored to cereal or other food agri- culture. Before leaving the hydrocarbons proper, it should 40 ORGANIC CHEMISTRY. be stated that compounds of carbon and hydrogen of extra-terrestrial origin have been found in certain met- eorites, by J. Lawrence Smith. (80-76-388.) CAMPHOR. Camphor is usually considered at this point, on ac- count of its intimate relation to the oxydized essential oils in composition, and to turpentine in many chemical reactions. Berthelot regards camphor as an aldehyd. Kekule places it among the ketones. Camphor exists in various parts of the Laurus camphora. To obtain it, the wood is finely divided and heated with water in a metallic vessel, closed by a cover filled with straw. The camphor is condensed in grayish crystals on the straw, forming the crude cam- phor of commerce ; it is afterwards sublimed in a glass retort as a further purification. Camphor is a crystallized body, having a burning taste and an aromatic odor. Its density is 0.99 at 10°. It is elastic and with difficulty pulverized, which can, however, be easily effected on moistening with a few drops of alcohol. Water dissolves only about -^-^ part of it ; thrown upon pure water it floats on the surface with a gyratory motion. It is soluble in alco- hol, ether, acetic acid and essential oils ; it is sublimed at ordinary temperatures where kept in close vessels, and deposits again on the cooler side of the recep- tacle. It burns with a smoky flame and oxydizes on being RESINS, BALSAMS, GUM-RESINS. 41 boiled with nitric acid, yielding camphoric acid O 10 H 16 O 4 which is bibasic. Heated with zinc chloride or anhydrous phosphoric acid, it furnishes Cymol C 10 H 14 . The author found (1-146-73; that on treatment of camphor with hypochlorous acid he obtained the new body, C 10 H 15 ClO, which he denominates monochlor- camphor\ this, on treatment with alcoholic potassium hydrate, yielded oxy camphor C 10 H 16 O 2 . Camphor is very extensively employed in medicine and pharmacy. RESINS, BALSAMS, GUM-RESINS. These bodies are products of the oxidation of essen- tial or volatile oils. The name of gum-resin is applied to those which contain a gum, and balsam to those which contain essential oils and an acid, usually cin- namic or benzoic, in addition to the resin which is presented in both. A. B. Prescott, the eminent au- thority on proximate analysis, defines balsams as " natu- ral mixtures of volatile oils with their oxidation pro- ducts, — resins and solid volatile acids. " They are substances more or less colored, hard and brittle. They are fusible, n on- volatile, and burn with a fuliginous flame. They are insoluble in water, gen- erally soluble in alcohol, ether and essential oils. Several of them are acid. This is the case with the most important of them, as the resin of the pine, called colophony, from which three isomeric acids have been obtained — the pinic, sylvic, and pimaric, C20H30O2. 42 ORGANIC CHEMISTRY. This resin constitutes the fixed residue obtained on distilling crude turpentine* It is used for preparing varnish, in soldering, and in certain combinations with the alkalies, called resin-soaps. Subjoined are given the names and the origin of the principal resins, oleo-resins, gum-resins and balsams. "With some, the position assigned them in this classi- fication is not definitely settled. EESINS. Amber is found in the lignites and in the alluvial sands of the Baltic. Arnicin, the active principle of Arnica Root. Cannabin, the active principle of Indian Hemp* Castorin, a secretion of the Beaver {Castor). Ergotin(?), the active principle of Ergot of common rye. Mastic, a resinous exudation of the Mastic, or Lent- isk tree. Burgundy Pitch, an exudation of the Spruce Fir, Abies excelsa. Pyrethrin, the active principle of the Pellitory root. Pottlerin, a crystalline resin from Kamala, the min- ute glands which cover the capsules of Bottler a tinc- toria. OLEO -EESINS. Copaiva, a resinous juice of the eopaifera officinalis found in Spanish America. Wood-oil, an oleo-resin from the Dipt ero carpus turbinates. RESINS, BALSAMS, GUM-RESLTSTS. 43 Elemi, an exudation of an unknown tree, (probably C armarium commune). Common Frankincense, a concrete turpentine of the Pinus tceda. Canada balsam, the turpentine of the Balm of Grilead Fir, (Abies balsamea). Storax, from the Liquidambar orientale. GUM-RESINS. Ammoniacum, an exudation of the Dorema ammo- niacum. Assafoetida, a gum resin obtained by incision from the living root of the JVarthex assafoztida. Gamboge, obtained from the Garcinia morella. G-albanum, from the galbanum officinale. Myrrh,an exudation of the Balsamodendronmyrrha. BALSAMS. Benzoin, obtained from incisions of the bark of Styrax benzoin. Balsam of Peru, from the Myroxylon Pereirm. Balsam of Tolu, obtained from incisions of the bark of Myroxylon tuluifera. Caoutchouc is the hardened juice of Ficus elastica^ Jatropha elastica, Siphonia eahuchu, and other plants. Grutta-percha is the concrete juice of the peroha (Malay) tree the Isonandra percha, a sapotaceous plant. 44 ORGANIC CHEMISTRY, ALCOHOLS. GENERAL DEFINITION AND CHARACTERISTICS. This name is given to a class of neutral bodies as important as they are numerous. Their essential characteristic is that of reacting upon acids so as to form water and a class of bodies called ethers. The number of alcohols is very considerable. There are several distinct varieties of alcohol recognized. I. Those built on the type of one molecule of water: Vr 5 [ O, ethyl or common alcohol. II. On two molecules of water : 2 tt 4 [ 2 , ethylene alcohol or glycol. III. On three molecules of water : V 5 j- 3 , glycerine and thus on. They may be defined as bodies built on the type of one or more molecules of water having one-half of the hydrogen replaced by a hydrocarbide radicle. MONATOMIC ALCOHOLS, or those formed on the type of one molecule of water, ALCOHOLS. 45 of which ordinary alcohol is the best studied, are characterized by the fact that they contain one atom of oxygen only, and that by reaction with the mono- basic acids they form but a single ether. They may be obtained synthetically, as well as by various indirect processes. Subjoined is a classified list of the more important monatomic alcohols: FIRST SERIES, C n H 2n + 2 0. Methyl alcohol (wood spirit), C H 4 O Ethyl alcohol, (spirit of wine) C 2 H 6 O Propyl alcohol - - C 3 H 8 O Butyl alcohol, - - - C 4 H 10 O Amyl alcohol, - - C 5 H 12 Setyl alcohol - - - C 6 H 14 Octyl alcohol - - C 8 H 18 Sexdecyl alcohol - - - C^H^ O Ceryl alcohol - - C 27 H 56 O Myricyl alcohol - - - C 30 H 62 O . SECOND SERIES, C n H 2n O. Yinyl alcohol - - C 2 H 4 O Allyl alcohol - - - C 3 H 6 0. THIRD SERIES, C n H 2n _ 2 0. Borneol alcohol - - C 10 H 18 O. 46 ORGANIC CHEMISTRY. FOURTH SERIES, C n H 2n _ 6 0. Benzyl alcohol C 7 H 8 Xylyl alcohol C 8 H 10 O Cumol alcohol C 9 H 12 Cymol alcohol - C 10 H u O FIFTH SERIES, C n H 2n _80. Cinnyl alcohol C 9 H 10 O Cholesteryl alcohol - C 26 H^O MoNATOMIC ALCOHOLS HAYING THE GENERAL FORMULA, C n Ii 2n+2 0. METHYL ALCOHOL, OR WOOD-SPIRIT. CH 4 = C ^ 3 1 O. This substance is found in the liquid obtained on distilling wood. The distillate contains in addition, water, acetic acid, tar, and various oils. In order to extract the methyl alcohol, it is again distilled and that portion which passes over at 90° is collected ; this is diluted with water, the oil which precipitates sepa- rated, and the liquid agitated for a considerable time with olive oil. This oil is then removed, the liquid redistilled several times and only that portion collected which passes over above 70°. On being again ALCOHOLS. 47 distilled with calcium chloride it furnishes methyl al- cohol, nearly pure, boiling at 66.5°. There are other methods of rectifying besides the one here given. This body possesses most of the general properties of ordinary alcohol. Under the action of the oxides it furnishes an aldehyd and formic acid. Witih the acids it produces ethers; viz., with PIT I hydrochloric acid, methyl chloride, CH 3 C1= ™ 3 f 5 with acetic acid, "R j methyl acetic ether, C 3 H 6 2 =p Tin \® m Chloroform, CHC1 3 . Methyl chloride produces with chlorine a regular series of products of substitution. One of these terms, CHC1 3 , is the very important body, chloroform, dis- covered in 1831 by Soubeiran and Liebig. To prepare this compound, 40 litres of water, 5 kilos of recently slacked lime, and 10 kilos of chloride of lime are heated to 40°; 1500 grams of 90 per cent, alcohol are then added and the retort luted with clay. It is now heated for a moment to the boiling point and the fire then at once slackened. The ebullition having ceased there will be found two layers in the receiver. The upper layer is formed of water and alcohol, the lower one is chloroform nearly pure. The latter is washed with water, agitated with a dilute solution of potassium carbonate, or with fused 48 ORGANIC CHEMISTRY. calcium chloride for twenty-four hours, and distilled to four-fifths. Chloroform is a colorless liquid. When first pre- pared it has a sweetish penetrating taste, and an agree- able, ethereal odor. Its density is 1.48; it boils at 60.5°, is soluble in alcohol and ether and difficultly so in water. It burns, though not readily; its flame having a green margin. It dissolves iodine, sulphur, phos- phorus, fatty substances and resins. An alcoholic solution of potassa decomposes it into chloride and formiate : CHC1 3 + 4KHO = 3KC1 + CHK0 2 + 2H 2 0. Physiological Action. Chloroform is at present very generally used as an anesthetic. Opinions as to its manner of acting are divided. Formerly it was thought that the insensi- bility produced was the commencement of asphyxia. Since then it has been ascertained that the heart, in case of poisoning by chloroform, immediately loses all power of contraction, and it is now generally admitted that paralysis of the muscles and nerves of the heart is produced. As the vapor of chloroform is very dense, care should be taken that in its use, access of air to the lungs be not wholly prevented, or serious consequences may re- sult. Probably the fatal accidents that have occurred ALCOHOLS. 49 may, in some instances at least, be attributed to lack of care in this regard. It is of great importance that the chloroform used should be quite pure. In some cases it has been found to have undergone spontaneous decomposition after exposure to a strong light. It ought to communicate no color to oil of vitriol when agitated with it. The liquid itself should be free from color or any chlorous odor. When a few drops are allowed to evaporate on the hand no unpleasant odor should remain. Shuttleworth (100, 4, 339) states that partially de- composed chloroform can be rectified by agitating it with a solution of sodium hypo-sulphite. OKDINAKY ALCOHOL. Ethtlic, ok Yinic Alcohol. Formula: C2H 6 0. Density of vapor 23. Density .81. Boils at 78.4o. Cannot be solidified. It is prepared by the fermentation of saccharine liquids at a temperature of 25° to 30°, in the presence of a small quantity of a ferment. Cane sugar does not directly, become alcohol under the influence of a ferment. It is first transformed into two other sugars, glucose and levulose. 50 ORGANIC CHEMISTRY. C 12 H 22 O n + H 2 0=C 6 H 1 A+C 6 H 1 o - 6 . Glucose. Levulose. In its final fermentation nearly all the sugar is changed into alcohol and carbon dioxide, C 6 H 2 G =2C 2 H 6 0+4C0 2 . This equation accounts for the transformation of 94 to 96 per cent, of the sugar employed, but besides alcohol and carbon dioxide, succinic acid is always formed as well as glycerine, and in most cases " fusel oil," consisting chiefly of amyl alcohol. Fermentation is a phenomenon correlative with the development and growth of cells of the fungus My co- derma (Torula) cerevisice which constitutes yeast. Sometimes the sugar is furnished as a natural product by fruits ; often glucose is produced from the starch of cereals, potatoes, etc., and then changed into alcohol afterwards. Corn is the leading original source in this country. Alcohol obtained by fermentation is concentrated by distillation. This operation is performed in retorts, the construction of which is based upon a principle developed by A. de Montpellier, and improved by Derosne, Dubrunfaut and others. The object is to prevent the distilling over of the water with the alco- hol, and is quite well accomplished by the improved methods now employed. The details are not suited to the scope of this work. The application of this rational method of distilling ALCOHOLS. 51 admits of obtaining liquids containing xip to 90 per cent, of alcohol, but it is difficult to go beyond that point of concentration. In order to prepare alcohol more concentrated, sub- stances having a great avidity for water must be used. Calcium chloride is not suitable, as it unites with the alcohol. Anhydrous sulphate of copper, carbon- ate of potassium or quicklime do not produce absolute alcohol. But it is very rare that perfectly anhydrous alcohol is required. Alcohol of 97 per cent, is obtained in treating alcohol of 85 per cent, during two days with lime, or better, with a sixth or seventh part of its weight of dry potassium carbonate, and then distilling. If it is desired to procure absolute alcohol, very concen- trated alcohol is treated with caustic baryta until the liquid is colored yellow and then distilled. Alcohol in fresh bread made with yeast has been found by Bolas (8-27-271) to the amount of .314 per cent. Slices of bread a week old contained .12 to .13 per cent. Absolute alcohol is a colorless liquid, more limpid than water, of an agreeable odor and a burning taste. It boils at 78.4°, is neutral, combustible and burns with a flame but little luminous. It heats on coming in contact with water, and attracts the moisture of the air very rapidly. It contracts upon mixing with water; the max- imum of contraction takes place at a temperature of 15° when 52.3 vol. of absolute alcohol are mixed with 47.7 vol. of water; instead 100 vol. one obtains 20 per cent 14 to 16 75 to 12 10 to 12 10 to 16 2 to 1 1 to 8 b2 ORGANIC CHEMISTKY 96.3 vol. At the moment of admixture numerous air bubbles escape and the mixture becomes heated. The alcoholic strength of the liquids consumed as beverages varies considerably. Madeira wines, about Malaga " Bordeaux " " Khine " " California " " Cider " " Beer " " Spirits are distilled from fermented liquids; hrandy from wine ; whisky from a mash of corn or rye ; rum from molasses, etc. They contain about 50 per cent, of alcohol. The term proof spirits was originally given to al- cohol sufficiently strong to fire gunpowder when lighted. The strength of proof spirits now varies in different localities, and it would be well were this ambiguous designation no longer employed. Alcohol dissolves the caustic alkalies, certain ni- trates, chlorides and other salts, also various gases. With some of these, genuine chemical combinations are produced, and not mere solutions; this is the case with calcium chloride and magnesium nitrate. Alcohol can be mixed with ether in all proportions; it dissolves the resins, essential oils, and a great num- ber of other organic bodies. The chemical properties of alcohol are very inter- ALCOHOLS. 53 esting. Vapor of alcohol is decomposed on passing through a tube heated to redness; hydrogen, marsh- gas, oxide of carbon, small quantities of naphthalin, benzol, and phenol are formed. In presence of air and water it slowly oxidizes and yields acid com- pounds. This action is rapid, if a hot spiral of plati- num is placed in the alcoholic vapor. Experiment. — Place a small platinum spiral in the wick of an alcohol lamp, light and theu blow out the flame. It will be seen that the spiral remains incan- descent. Spongy platinum acts still more energetically; if very concentrated alcohol is poured drop by drop into a capsule containing spongy platinum, or platinum black, it will be seen to redden, fumes are produced and an acid liquid is formed containing chiefly aldehyd and acetic acid. The same oxidation occurs if diluted alcohol is exposed to the air in the presence of mother of vinegar, a cryptogamic plant, (Mycoderma aceti). In fact, this is the basis of the manufacture of wine-vin- egar and alcohol. Fuming nitric acid reacts upon alcohol with ex- plosive energy. Aldehyd is formed, also acetic ether, nitrous ether and acetic, formic, gly collie, oxalic and carbonic acids. Alkaline hydrates attack alcohol even in the cold potassium acetate being the chief product formed. If alcoholic vapor is made to pass over lime heated to 250°, hydrogen gas and calcium acetate are produced; the latter is decomposed at a more elevated temperature into marsh gas and water. If silver or mercury is dissolved in nitric acid, and 90 per cent, alcohol added to the cooled solutions, a 54 ORGANIC CHEMISTRY. lively ebullition results, and a crystalline precipitate is deposited which explodes at 185°, or by percussion. This body is the fulminate of silver or mercury, re- spectively, which is considered as derived from methyl cyanide, CH 3 Cy, by the substitution of 1 molecule of nitryl, and of 1 atom of mercury, or 2 of silver for 3 atoms of hydrogen. The formulae are C(N0 2 )HgCy; C(N0 2 )Ag,Cy. Potassium attacks absolute alcohol, and is dissolved liberating hydrogen; on cooling, potassium ethylate is deposited. Sodium acts in the same manner. These compounds, if brought in contact with water, regenerate alcohol and the respective alkaline hydrates. Acids attack alcohol and furnish compound ethers, which we will study later. Ozone, according to A. W. Wright, (80 — 1_3]7 — 181) oxydizes alcohol to acetic acid. Physiological Action of Alcohol. Uses of Al- cohol. — Alcohol coagulates the blood; injected into the veins it produces instantaneous death. It is a very powerful poison, as are all alcohols of the series CnH^O. Rabuteau (9 — 81 — 631) has shown that they are more poisonous in proportion as their mole- cules are complex. Cases have been observed where a large dose of alcohol has caused death in half an hour. The worse than worthless character of distilled liquors as beverages is no longer an open question. With regard to their value as food or medicine, a more authoritative or competent expression of opinion can- not be desired than that of the International Medical Congress, which at its session in Philadelphia in 1876, said: ALCOHOLS. 55 "1. Alcohol is not shown to have a definite food value by any of the usual methods of chemical analy- sis or physiological investigation. " 2. Its use as a medicine is chiefly that of a cardiac stimulant, and often admits of substitution. " 3. As a medicine, it is not well fitted for self-pre- scription by the laity, and the medical profession is not accountable for such administration, or for the enormous evils arising therefrom. " 4. The purity of alcoholic liquors is, in general, not as well assured as that of articles used for medicine should be. The various mixtures when used as medi- cine, should have definite and known composition, and should not be interchanged promiscuously." The dissolving power of alcohol renders it very ser- viceable in the arts. Solutions in this menstruum are called alcoholic tinctures. Only the purest alcohol ought to be used in pharmacy, though of course, various strengths are requisite, as it should be of a degree to suit the nature of the matter to be dissolved. If the substance to be treated is a resin, or some substance absolutely insoluble in water, a very concentrated alco- hol is preferable. A weaker alcohol is made use of, if the matter is one that is soluble, both in alcohol and water. Alcohol acts not only as a solvent, but also as a pre- ventative of decay. This is a property which renders it especially valuable in the preparation of remedies. 56 ORGANIC CHEMISTRY AMTL ALCOHOL. C 3 H 12 = C 5 H„ H Synonyms: Fotjsel (oe Fusel) Oil, Potato Spieit. The amylic compounds derive their name from Amylum, starch, the chief constituent of the potato. They are formed in some proportion in almost every in- stance of alcoholic fermentation of sugar. Amylic alcohol is usually prepared on fractionally redistilling the oil which remains when the alcohol, prepared from potatoes, barley, corn, etc. , is distilled. The pro- duct which comes over at 132°, is that collected. Cahours and Balard first established the analogy, in constitution and properties, of this compound with ordinary alcohol. It is a monatomic alcohol, giving with oxidizing re-agents, valeric acid. C 5 H 12 0+0 2 = C 5 H 10 O 2 +H 2 O, Amylic alcohol. Valeric acid. and with acids, compound ethers, as Chloride of amyl, C 5 H n Cl. Acetate of amy] or amyl-acetic ether, n 5 ^ 1 /! r ®' ALCOHOLS. 57 MONATOMIC ALCOHOLS. Having the general Formula C n H 2n O. Allylic Alcohol, C 3 H 6 === C§H 5 ) n H f U * This is a body giving the same reactions as ordinary alcohol. The radicle it contains is the same as that in the triatomic alcohol, glycerine. Among its deriva- tives there are two which are of considerable impor- tance : Allyl sulphide, ^ 5 i S. Sulpho-cyanide, C^ \ ®' The former is oil of garlic; the latter oil of mustard. Oil of garlic is prepared by the following method: allylic alcohol is treated with phosphorus iodide which furnishes allyl iodide C 3 H 5 I. This iodide is afterwards mixed with an alcoholic solution of potassium sulphide and the whole is distilled; the product which passes over is identical with the essential oil obtained in dis- tilling garlic, onions, assafoetida, etc., with water. OIL OF MUSTARD, OR SULPHO-CYANIDE OF ALLYL. This body is prepared by causing iodide of allyl to react upon potassium sulpho-cyanide, xr f S, and may be regarded as sulpho-cyanic acid, o f S, having the 58 ORGANIC CHEMISTRY. hydrogen replaced by the radicle of allyl alcohol, C 3 H 5 . The product which distills over is an irritating liquid which boils at 145°, like the oil prepared from mus- tard directly. This substance may also be obtained by the action of allylic alcohol upon potassium sul- pho-cyairide. It is likewise obtained by the fermenta- tion of mustard seeds. Sulpho-cyanide of allyl does not exist already formed in black mustard (Sinapis nigra), but according to Bussy, its formation is due to a particular ferment. Oil of mustard combines directly with ammonia, forming a crystalline substance called thiosinnamine, C 4 H 8 N 2 S, which, in contact with mercuric oxide, changes into an alkaloid called sinnamine, of which the composition is C 4 H 6 N 2 . It reacts upon lead oxide producing a substance called sinapoline whose formula is c 7 H 12 ]sr 2 o. BORNEO CAMPHOR, OR BORNEOL C 10 Hi 8 O. This body exudes from the Dry obalcmops camphor a (Borneo). It is crystalline and has an odor between that of camphor and pepper. It fuses at 195°, and boils at about 220°. It is dextrogyrate. Heated with nitric acid it furnishes common camphor C 10 Hi 6 O. DIATOMIC ALCOHOLS OR GLYCOLS. Ordinary Glycol, (C S H 4 ) — 3 — H 3 =C 3 H 6 3 Propyl " (C 3 H 6 ) _0 2 -H 2 =C 3 H 8 2 ALCOHOLS. Butyl Glycol, Amyl Hexyl " Octyl (C 4 H 8 )-O 3 -H 3 =C 4 H 10 O 3 (C 5 H 10 )-O 3 -H 3 =C 5 H 12 O 2 (C 6 H 12 )-0 2 -H 2 =C 6 H 14 2 (C 8 H 16 )— 2 — H 2 =C 8 H 18 2 59 TRIATOMIC ALCOHOLS. Glycerine, (C 3 H 5 )-0 3 -H3=C 3 H 8 03. TETRATOMIC ALCOHOLS. Erythrite, (C 4 H 6 )— 4 — H 4 =C 4 H 10 O 4 . OTHER COMPLEX ALCOHOLS. Glucose and its isomerides, (C 6 H 6 ) — 6 — H 6 =C 6 H 12 6 . Mannite, - - (C 6 H 8 )— 6 — H 6 =C 6 H 14 6 . Dulcite, - - - (C 9 H 8 )-0 6 -H 6 -C 6 H 14 6 . ORDINARY GLYCOL. C 2 H 6 2 =( C g 2 }0 2 . The discovery of the glycols was an event of great importance. It was achieved by Wurtz in 1856, and the glycol of which we are treating was the first discovered. In a flask surmounted by a condenser, two parts of potassium or sodium acetate, are dissolved in weak alcohol and one part of ethylene bromide added. This 60 ORGANIC CHEMISTRY. mixture is heated in a water bath as long as the pre- cipitate of alkaline bromide continues to form, care being taken at the same time to keep the worm well cooled, in order that the vapors of alcohol may contin- ually now back into the flask. The alcohol is* distilled off in a water bath, and the residue afterwards also distilled at a higher temperature, and that part col- lected which passes over between 140° and 200° . This portion which contains monacetic glycol, is heated with a saturated solution of baryta until the liquid acquires a strong alkaline reaction. The excess of baryta is removed by passing carbon dioxide through the solution which is then filtered and evaporated. The barium acetate is precipitated completely by strong alcohol, and the alcohol subsequently removed by dis- tillation. The retort is now heated in an oil bath, and that portion set aside which boils above 150° . This is redistilled and the distillate between 190° and 198° is the product sought. Zeller and Huefner have lately (18, 10,270) obtained the purest glycol by simply heat- ing a solution of potassium carbonate with ethylene bromide. Glycol is a colorless, odorless liquid, somewhat viscid and having a sweetish taste. Its density is 1.12; water and alcohol dissolve it in all proportions. Ether dissolves it with difficulty. It is not oxydized in the air under ordinary con- ditions, but if dilute glycol be made to fall on plati- num black, it becomes heated and is transformed into gly colic acid. Its equivalence is shown by the follow- ALCOHOLS. 61 ing : glycol attacks sodium forming two sodium glycols; C 2 H 4 ) n C 2 H 4 ) n JSTaH | U2 ' NaJ 2 * These glycols furnish two ethyl glycols on being heated with ethyl iodide. C2H4 \ r\ C 2 H 4 ) ^ C 2 H 5) Hf°^ (0 2 H 5 ).J° 2 - Ethyl-glycol. Diethyl-glycol. "With hydrogen bromide it furnishes two different products according to the number of molecules of HBr taken. C 2 H 6 2 + HBr = C 2 H 5 BrO + H 2 0. Monobromhydric ether. C 2 H 6 2 + 2HBr=C 2 H 4 Br2f 2H 2 0. Ethylene bromide . It is evident that mixed ethers may be obtained by treating glycol not with two molecules of the same acid, but with two molecules of different acids. Thus O TT ) aceto-chlorhydric glycol is formed ,p tt Q\pi 4 r O. 62 ORGANIC CHEMISTRY. These ethers, in the presence of alkalies, are re- formed into their respective acids and glycol, in the same manner in which ethers of ordinary alcohol regenerate alcohol. Monochlorhydric and aceto-chlorhydric glycol form an exception to this rule ; they form oxide of ethylene in presence of alkalies. OXIDE OF ETHYLENE, C 2 H 4 0, a polymer of (CalX^C^, is related to glycol as ordinary ether to alcohol. It is not obtained like the latter by the action of hydrogen sulphate on the alcoholic compound, but is produced by the action of potassa on mono- chlorhydric glycol. A solution of potassa is gradually poured into chlorhydric glycol placed in a glass, or a tubulated retort. KHO + C 2 H 5 C10 = KC1 + H 2 + C 2 H 4 0. The oxide of ethylene distills over with the water; the latter is absorbed by causing the vapors to pass through a flask containing anhydrous calcium chloride, and the oxide is condensed in a receptacle placed in a refrigerating mixture. It is a colorless, ethereal, fragrant liquid; boiling at 13°. Its density is 0.89. Ethylene oxide is very solu- ble in water, alcohol and ether. It burns with a lumin- ous flame and reduces silver salts. It has the compo- sition but not the properties of aldehyd, of which it is an isomeride. ALCOHOLS. 63 Oxide of ethylene is a very remarkable body. It combines directly with oxygen, hydrogen, chlorine and bromine, also combines directly with acids, often even with the disengagement of heat, forming the ethers of glycol and polyethylenic alcohols. This body is there- fore a true non-nitrogenous basic oxide. 64 ORGANIC CHEMISTRY. TKIATOMIC ALCOHOLS OE GLYCEEDTES. Ordinary Glycerine, C 3 H 8 3 = 3 tt 5 [ O, . This body, discovered by Scheele, in 1779, and called by him, on account of its sweet taste, the sweet principle of oils, has been specially studied by Chevreul and by Pelouze. Berthelot discovered its real nature and proved it to be a tri atomic alcohol. Glycerine is prepared by decomposing neutral fatty bodies, in the soap and candle industry by alka- lies, or better still by superheated steam. {TilghmarCs process.) It is obtained in pharmacy, whenever lead plaster is prepared and remains in the water with which the latter is washed. It is much employed in pharmacy and perfumery and as a solvent for many substances. Crude glycer- ine may be purified by boiling with animal charcoal and filtering before being evaporated to the required consistency. The best process consists in distilling the crude condensed glycerine in a current of steam. Pas- teur has shown that glycerine is produced in a very small quantity in alcoholic fermentation. We owe to "Wurtz, a remarkable synthetical reproduction of glycer- ine. Propylene C 3 H 6 furnishes an iodide C 3 H 5 I, called iodide of allyl. This body produces with bromine the ALCOHOLS. 65 compound C 3 IL;Br 3 which, treated with potassa, or oxide of silver, yields glycerine. C 3 H 5 Br 3 +3KHO = 3 KBr.+C 8 H 8 8 . Glycerine . Glycerine is a syrupy liquid, colorless, of a sweetish taste and destitute of odor; its density is 1.28 at 15°. Sarg has obtained crystals of glycerine, whose angles have been measured by Victor Lang (2-152-637). They are rhombic in form and very deliquescent. Glyc- erine is soluble in alcohol and water in all propor- tions; it is not dissolved by ether. It dissolves alka- lies, alkaline sulphates, chlorides and nitrates, copper sulpnate, silver nitrate and many other salts. Glycerine distills at 280°, but is thereby partially decomposed. It may, however, be distilled in a vacuum without change. It is decomposed at a tem- perature above 300°, and oils, inflammable gases, carbon dioxide, and a product very irritating to the eyes, called acrolein* acrylic aldehyd, are formed; this last substance may be obtained pure by distilling glycerine with, sulphuric, or phosphoric acid. The formula of acrolein is C 3 H 4 2 ; it is also produced in the dry distillation of all fatty bodies which contain glycerine. If glycerine be made to fall drop by drop upon platinum black, it unites, like alcohol and glycol, with 2 and glyceric acid is formed. C 3 H 8 3 + O a =C 8 H 6 4 + H 2 0. The oxidation of the glycerine does not stop here; 66 ORGANIC CHEMISTRY. there is subsequently formed, acetic, formic, and car- bonic, but chiefly oxalic acid. The action of acids on glycerine demonstrates two facts; first, that glycerine is an alcohol; second, that it is a triatomic alcohol. On treating glycerine with hydrochloric acid the first reaction is similar to that between alcohol and this acid, HC1+C 3 H 8 3 =C 3 H 7 C10 2 +H 2 0. Monochlorhydric ether, or Monochlorhydrin. The continued action of phosphorous perchloride upon glycerine, or the dichlorhydrate of glycerine, effects the elimination of additional molecules of water and the formation of trichlorhydrin. 3HC1+C S H 8 3 =C 8 H 5 C1 S + 3(H 2 0). Trichlorhydrin. Berthelot has studied the acetines. butyrines (tri- butyrine exists in butter), valerines, and many other ethers of glycerine. If glycerine is mixed with cold nitric acid, and sulphuric acid added drop by drop, an oily substance separates out which is tr dnitro glycerine, C 3 H 3 (]^Oo) 3 3 . This body detonates with great vio- lence. It acts very energetically on the system. A few drops placed on the tongue produce violent me- grim. Glycerine forms compounds with lime anal- ogous to those formed by sugar, according to P. Car- les, (1-174-87). ALCOHOLS. 67 Uses. — The uses of glycerine in the arts, and especially in pharmacy, are numerous and important, many of which are based upon the solvent power of this compound. Henry Wurtz (31-195-58) has made valuable suggestions as to its economical applications. TABLE SHOWING THE SOLUBILITY OP SOME CHEMICALS IN GLYCERINE, (FROM KLEVER.) ONE HUNDRED PARTS OP GLYCERINE DISSOLVE THE ANNEXED QUANTITIES OP THE FOLLOWING CHEMICALS: Arsenous oxide, 20.00 Arsenic oxide, 20.00 Acid, benzoic, 10.00 " oxalic, 15.00 " tannic, 50.00 Alum, 40.00 Ammonium carbonate, 20.00 " chloride, 20.00 Antimony and potassium tartrate, 5.50 Atropia, 3.00 Atropia sulphate, 33.00 Barium chloride, 10.00 Brucia, 2.25 Cinchonia, 0.50 " sulphate, 6.70 Copper acetate, 10.00 " sulphate, 30.00 Iron and potassium tartrate, 8.00 " lactate, 16.00 " sulphate, 25.00 Mercuric chloride, 7.50 Mercurous chloride, 27.00 Iodine, 1.90 Morphia, 0.45 Morphia acetate, 20.00 " chlorhydrate, 20.00 Phosphorus, 0.20 Plumbic acetate, 20.00 Potassium arsenate, 50.00 " chlorate, 3.50 " bromide, 25.00 " cyanide, 32.00 " iodide, 40.00 Quinia, 0.50 " tannate, 0.25 68 ORGANIC CHEMISTRY. Sodium arsenate. 50.00 " bicarbonate, 8.00 " borate, 60.00 " carbonate, 98.00 41 cblorate, 20.00 Sulpbur, 0.10 Strychnia, 0.25 " nitrate, 4.00 " sulphate, 22.50 Urea, 50.00 Veratria, 1.00 Zinc chloride, 50.00 " iodide, 40.00 " sulphate, S5.00 ETHERS* 69 ETHERS. SIMPLE ETHEKS. Ethers are products formed by the action of alcohols upon acids. By most chemists they are looked upon as referable to the oxides of metals ; thus p-rr 3 [ O and p 2 -rr 5 [ O, may be regarded as the oxides respectively of methyl and ethyl. They bear the same relation to alcohols that oxides of the metals do to the hydrates. Potassium hydrate KOH. Ethyl hydrate, or ethyl alcohol C 2 H 5 OH. Potassium oxide ^ I 0. Ethyl oxide or ethyl ether ^ 2 ^ 5 l O. The simple ethers are mostly liquid. They are very slightly soluble in water, while they are readily soluble in alcohol. Exposed to the action of alkaline solu- tions they regenerate alcohol. C 4 H 8 2 +KHO = C 2 H 6 0+KC 2 H 3 2 . 70 OKGANIC CHEMISTRY. ETHYL ETHER. Synonyms : Vinic ether, sulphuric ether, common ether. Density .736. Density of vapor, 37. Specific gravity of vapor, 2.586. Boiling point, 35.5°. To prepare this compound, sulphuric acid is heated with alcohol in a retort, placed in a sand-bath. The ether distills, its vapor being received in a well cooled condenser, provided with a long tube which conducts the uncondensed vapor into a chimney. The cork adapted to the tubulure of the retort is provided with two openings ; in one is fixed a ther- mometer, through the other a tube passes which fur- nishes the supply of alcohol. All the connections should close perfectly. When the apparatus is arranged in this manner, pour TOO grams of 85 percent, or 90 per cent, alcohol into the retort, and add, little by little, 100 grams sulphuric acid of 1.84 sp. gr., then heat. When the thermometer attains 130°, cause the alcohol to flow from the upper vessel at a rate sufficient to keep the temperature between 130° and 140°. The weight of alcohol capable of being transformed into ether is from 13 to 15 times the weight of the mixture first in- troduced into the retort. The distilled liquid is mixed ETHEKS. 71 with 12 parts, to every 100 of its weight, of a solution of soda having a specific gravity of 1.32, and agitated from time to time, during 18 hours. The ether is decanted by means of a glass siphon, redistilled and four-fifths of the liquid collected. The remainder may serve for a future operation. This furnishes ordinary ether. To further purify, wash with water, decant and treat for two days with equal parts of quick lime and fused calcium chloride. "Wil- liamson has clearly shown that etherification takes place in two stages or successive reactions as follows: C 2 H 6 + H 2 S0 4 = H 2 + (C 2 H 5 )HS0 4 . Ethylsulphuric acid. (C 2 H 5 )HS0 4 + C 2 H 6 = C 4 H 10 O + H 2 S0 4 . This explains how a small quantity of sulphuric acid etherizes a large amount of alcohol, since sul- phuric acid is constantly regenerated. This is con- firmed by the following experiment. Iodide of ethyl is made to react upon potassium alcohol ; ether is obtained as indicated by the reaction; C 2 H 5 I + C 2 H 5 OK = C 4 H 10 O + KI. Ether is a neutral, volatile liquid, colorless, having a burning taste and a strong agreeable odor. When agitated with water it rises to the surface, but the water dissolves about one ninth of its own weight of the ether. It is miscible with alcohol in all propor- 72 ORGANIC CHEMISTRY. tions and with wood spirit. Ether is frequently adul- terated with the latter substance. Next to alcohol it is the most generally employed solvent for organic substances. It dissolves resin, oils and most com- pounds rich in carbon and hydrogen. Bromine, iodine, chloride of gold and corrosive sub- limate are soluble in this liquid. It dissolves phos- phorus and sulphur in small quantity. "W. Skey (8 — Aug. 3, '77,) has shown that contrary to the usual statement in standard works, ether dissolves notable quantities of the alkalies. At a red heat it is decomposed and furnishes carbon monoxide, water, marsh gas and acetylene. It is exceedingly inflammable, and burns with a bright flame. Its extreme volatility, the density of its vapor, its insolubility in water and its great inflammability render its use dangerous, and explosions caused by it are of frequent occurrence. It should never be brought near a fire or light in open vessels. In case ether inflames, it is best, if possible, to at once close the vessel con- taining it, and thus avoid the more serious conse- quences ensuing from an explosion. Exposed to the air it experiences a slow combustion as in the case of alcohol, and the same compounds are the result. Chlorine acts violently upon it; in moderating the action, the whole or a part of the hydrogen may be replaced atom for atom by chlorine. Uses. — It is used in pharmacy in preparing etherial ETHEES. 73 tinctures, and as an antispasmodic and stimulant in the well-known Hoffmann's anodyne. Its most impor- tant use in medicine is as an anesthetic, than which none is safer or more reliable in efficient hands. It is extensively employed in the laboratory and in photography. COMPOUND ETHEES are bodies built up on the type of water, having one half the hydrogen replaced by a hydrocarbide and the other half by a compound radicle containing oxygen, or, in other words, by the radicle of an acid. (OHO ) n ACETIC ETHER, )p tr Q\ \ O. To prepare this ether 8 parts of very concentrated alcohol are distilled with 7 parts of sulphuric acid and 10 parts of anhydrous sodium acetate, which may be replaced by 20 parts of dry lead acetate. The distil- late is agitated with a solution of calcium chloride containing milk of lime, decanted, dried over calcium chloride and finally distilled. Seven parts of water dissolve one part of this body. Alcohol and ether dissolve it in all proportions. It is a solvent for many organic bodies. It is easily de- composed on contact with water. Potassa also effects this decomposition very readily. A prolonged action of ammonia transforms it into acetamide and alcohol. 74 ORG-AXIC CHEMISTRY. OXALIC ETHEES. Oxalic acid, being a bibasic acid, furnishes with alcohol two combinations, one being acid and capable of combining with bases ; the other is neutral. C.H :0 O 4 . Only the latter is of interest. It may be prepared by introducing four parts of 90 per cent, alcohol and four parts of oxalic acid into a retort, adding to this mixture three to six parts of sulphuric acid and then rapidly distnling ; the product is washed several times. dried, then redistilled, collecting only the liquid which passes over at 184°. This ether is aromatic, oily, and gradually decomposes in water. Potassium changes it into carbonic ether. If oxalic ether is agitated with ammonia, a white powder, oxamide. and ethyl alcohol are produced. (CoH 5 \ j , N ^ rr 2 _ H Oxamide may be considered as derived from two molecules of ammonia, and belongs to a class of bodies called d (amides. It is a white substance, insoluble in cold water and alcohol. Heated with mercuric oxide it is transformed into carbon dioxide and urea. (Williamson.) ETHERS. 75 Oxalic ether treated with ammonia in solution in alcohol furnishes oxamic ether. In this connection the compounds of the organic radicles with the haloid elements are usually studied: they are not unfrequently denominated ethers of the hydracids. Their type is a molecule of hydrogen, ^ I . CHLORIDE OF ETHYL OR CHLORHYDRIC ETHEK. ,H 5 C1— C 2 H 5 CI ( This body is formed in small quantity when ethy- lene is made to react upon hydrochloric acid. To prepare it, alcohol contained in a flask sur- rounded by cold water, is saturated with hydrochloric acid gas and the mixture then distilled. C3H 6 0+HC1=C 2 H 5 C1+H,0. It is also obtained by pouring into a flask contain- ing 2 parts common salt, a mixture of 1 part alcohol, and 1 part sulphuric acid : it is then gently heated and the ether collected as previously shown. It is a liquid of an agreeable odor, and very volatile, having a boiling point of 12° and a vapor density of 64°. A red heat decomposes it into ethylene and hydrochloric acid gas. It is combustible and burns with a green, smoky flame ; water dissolves the fif- tieth part of its volume, alcohol dissolves it completely. 76 ORGANIC CHEMISTRY. With chlorine it furnishes a complete and regular series of products of substitution which are not iden- tical, but isomeric with the chlorine products of ethene. Their formulae are: CgH 4 Cl 2 C 2 H 3 C1 3 CgH 2 Cl 4 C 2 H CI, C 2 Cl 6 . 2THYL OR HTD] C 2 H 5 I = C ^ i] is obtained on causing alcohol to react upon iodide of phosphorus; the action is violent with white phos- phorus, considerably less so with red phosphorus. Six hundred grams of concentrated alcohol are intro- duced into a retort with 140 grains of amorphous phosphorus, and to this mixture 450 grams of iodine are added. The distilling is carried nearly to dryness. The product, condensed in the receiver, is washed with water containing a little potassa ; afterwards with pure water. It is then dried over calcium chloride and again distilled. Iodide of ethyl is a colorless liquid. Its density is 1.975. It becomes colored on exposure to light, being slightly decomposed ; it is again rendered colorless on agitating it with an alkaline solution, which absorbs the ETHERS. 77 acid formed. It burns with a green flame, leaving a resi- due of iodine. Ammonium compounds in alcoholic, or aqueous solution, furnish ethylamine. This amine can be attacked in its turn by iodide of ethyl and yields diethylamine and oxide of tetrethylammonium. The knowledge of these reactions and their application to other iodides are the basis of a general mode for the preparation of organic bases originated by Hoffmann. Iodide of ethyl, unlike the chloride, is readily decom- posed by solutions of silver nitrate, giving a precipi- tate of silver iodide. (W + AgNO, = (C 2 H 5 ) N0 8 +Agl. CYANIDE OF ETHYL, OR CYANHYDRIC ETHER. C s H 5 N = 2 H 5 )_ This ether is obtained on distilling in an oil-bath 1 part of potassium cyanide, with 1-5 part of an alkaline sulpho-vinate. To the product, redistilled in a bath of salt-water, nitric acid is slowly added in excess ; it is then subjected to another distillation. Finally, it is dried over calcium chloride, and that which passes over from 195° to 200° is collected on redistillation. Cyanide of ethyl is a colorless liquid of an alliaceous odor, boiling at 97?. Cyanide of ethyl is decomposed by potassium hy- drate; ammonia is produced, and the acid obtained corresponds with a higher homologous alcohol. 78 ORGANIC CHEMISTRY. CK(0 2 H 5 ) + 2H 2 = JSTH 3 + C 3 H 6 2 . Propionic acid. M. Meyer observed some years ago, that if cyanide of silver is treated with iodide of ethyl, a liquid is formed, boiling at 82°, of an odor which is not that of ordinary cyanhydric ether. Gautier has shown that this is an isomeric body, and that there are two isomeric series of cyanhydric ethers. Hoffmann has given a dis- tinctive character to these bodies: under the influence of the alkalies they produce a fixed substance, but this is formic acid and not ammonia, and a volatile substance which is a compound ammonia. H ) CN(C 2 H 5 ) + 2H 2 0= CHA + C 2 H S } N. — H ) Formic acid. Ethylamine. Oegano-metallic Compounds. Iodide of ethyl attacks the metals and furnishes a class of bodies called organo-metalliG radicles. None of these bodies are found in nature. They are formed from the iodohydric ethers by the substitution of a metal for the iodine; Zn + 2(C 2 H 5 I) = (C 2 H 5 ) 2 Zn + ZnI 2 , 2Sn + 2(C 2 H 5 I) = (C 2 H 5 ) 2 Sn + Snl 2 . Practically these metallic radicles are obtained by various reactions: ORGANO-METALLIC COMPOUNDS. 79 1. By the action of the metal upon the iodide, for example; 2C 2 H 5 I + Zn 2 =(C 2 H 5 ) 2 Zn + Znl 2 . In certain cases, with tin for instance, the reaction is not as distinct, and there is formed in addition to stan- nethyl iodide, stannethyl iodides variously condensed. 2d. The metal is treated with another radicle; thus sodium-ethyl is prepared by the action of sodium upon zinc ethyl, (C 2 H 5 ) 2 Zn + Na 2 = Zn + 2C 2 H 5 ]Sra. 3d. On decomposing a metalloid compound radicle with a metallic chloride, 3ZnCl 2 +2(C 2 H 5 ) 3 P=3(C 2 H 5 )Zn + 2PC1 3 . 4th. Stannethyl is obtained by plunging a plate of zinc into a soluble salt of this radicle: the radicle is precipitated in the form of an oily liquid. Cacodyl, As(CH 3 ) 2 was the first discovered of this class of bodies. It was obtained by Bunsen on distilling arsenous acid with potassium acetate. The organic radicles combine with metalloids with more or less energy ; zinc -ethyl and cacodyl take fire in the air ; they also decompose water. The products of oxida- tion vary with the nature of the compounds employed; zinc-ethyl furnishes the body, CJI 5 ZnO, zinc-ethyl- ate, which, in contact with water, produces alcohol and oxide of zinc. The metals which are less readily oxy- 80 OEGAWIC CHEMISTEY. dized, such as tin, lead and mercury, give oxides which play the parts of bases, and these latter com- port themselves like the oxides of the metals they con- tain. Finally, the radicles formed by the elements, phosphorus, arsenic, and antimony, give, with oxy- gen, compounds which generally have the character of acids. Some of the organic derivatives containing phos- phorus are very complex. For instance, J. Auanoff (60-75-493) has obtained a body he denominates, methyldiethyljphosphoniuniphenyloxidehydrate! To prepare zinc-ethyl, we introduce into a flask connected with a condenser inclined in such a manner that the vapors find their way back into the flask, 100 grams iodide of ethyl, 75 grams of zinc, and 6 to 7 grams of an alloy of zinc and sodium, and heat in the water bath until the zinc is dissolved ; then the condenser is inclined as usual, and the distilling is effected over a direct fire, collecting the liquid pro- duct in a flask filled with dry carbon dioxide. Finally it is again distilled in this gas, and that col- lected which passes over from 116° to 120°. All the vessels and all the substances should be absolutely dry, and it should always be collected and distilled in vacuo, or in carbon dioxide. It is a colorless liquid, whose density is 1.182, boiling at 118°, inflammable on exposure to the air. With sodium this body furnishes sodium-ethyl, and with chloride of phosphorus or arsenic, it furnishes triethyl phosphine, P(C 2 H 5 ) 3 , and triethyl arsine, As (C a H 3 ) 8 . ETHERS. 81 Mercury-methyl, treated with iodine, furnishes a hydro-carbide which has the formula of methyl, CH 3 . Professors Crafts and Friedel (72-[4]19-334) have prepared a large number of compounds of silicon with compound radicles, from which they have deduced valuable theoretical considerations. MISCELLANEOUS ETHEKS. Formic, butyric, valerianic ether, and other ethers of the fatty series are prepared in the same manner as acetic ether, and have the general properties of this ether. The odor of these ethers is agreeable. Bu- tyric ether has the odor of pine-apple, and valerianic ether that of pears ; cenanthylic ether has the aroma of wine, etc. They are used in the manufacture of syrups, flavoring extracts, and for imparting an odor to liquors. If the difference between the points of ebullition of these ethers is examined it will be seen that the addition of the elements. CH 2 causes an elevation of about 20° in the point of ebullition. Kopp has shown that this fact is a general one and applies to the alcohols, and acids of the same series, and to the homologous bodies in general. Point of ebullition. Difference. Formic ether, - - 55° 1QO Acetic " - - 74° i% Propionic " - - 95° ^ Butyric " - - 119° ~* Valerianic" - - 133° * 82 ORGANIC CHEMISTRY. The boiling point of one of these bodies may accord- ingly be predicted, if that of one of its homologous substances is known. There is a certain close relation between the point of ebullition of an ether and that of the acid whose radicle it contains : Point of ebullition. Difference. Formic acid, ' - 105° ) - 55° [ " ether, 50° Acetic acid - 118° ( " ether, 74° j" U° Propionic acid, - H0° ) 95°) " ether, - 45° Butyric acid, 163° ) " ether, - - 119° \ 4A° The solubility in water of the ether formed by homologous acids varies with the molecular weight ; thus formic ether is quite soluble, acetic ether is less soluble, butyric ether is but slightly so, and valerianic ether, which follows it, is nearly insoluble. MERCAPTANS AND THEIR ETHERS. Od substituting sulphur, selenium, or tellurium for oxygen in the alcohols of different atomicity, sulphur, selenium, or tellurium alcohols are obtained, which are designated as mercaptans, selenium mercaptans, and tellurium mercaptans. Ethers proper correspond to these as to ordinary al- cohols. These ethers are derived either by the substi- ETHERS. 83 tution of an alcohol radicle for the typical hydrogen, as happens with monatomic mercaptans, or by the elimination of H 2 S, as is the case with biatomic mer- captans. One only of each of these two classes will be alluded to here. Ethyl sulphide, or hydrosulphu- Lnn = C 2 H 5 \ g ric ether, j 4 10 C 2 H 5 j Ethyl mercaptan, C 4 H 6 S= C2 g 5 j- S. To prepare the sulphide a current of ethyl chloride, is passed into an alcoholic solution of potassium sulphide. The mercaptan is prepared by the action of potass- ium hydro-sulphide on ethyl sulphide. In either case potassium chloride is formed. K 2 S +2C 2 H 5 C]==C 4 H 10 S-I-2KC1 KHS + C 2 H 5 C1=C 2 H 6 S + KC1. These bodies are afterwards separated by distillation. Like all the sulphur derivatives of alcohol, they have a nauseous odor. The sulphide boils at 91° the mer- captan at 36°. MIXED ETHERS containing two different radicles, are obtained by act- 84 ORGANIC CHEMISTRY. ing, for instance, with ethyl iodide upon potassium me thy late, thus : ethyl iodide, potassium potassium methyl-ethyl methylate. iodide. ether. or by acting on hydric methyl sulphate rr 8 \ S0 4 with ethyl alcohol. The following is a list of some of the more important mixed ethers of the monatomic series; TABLE OF MIXED ETHERS. BOILING POINT. Methyl-ethyl ether C 3 H 8 0= £j |[ 3 | O + 11° Methyl-amyl ether C 6 H 14 =£ § 3 1 O 92° Ethyl-butyl ether C 6 H u O = ^|* 5 \ O 80° Ethyl-amyl ether C 7 H 16 = ^ 2 ^ 5 \ O 112° Ethyl-hexyl ether C 8 H 18 - £?| 5 | O 132°. ALDEHYDS. 85 ALDEHYDS. The following are the principal aldehyds, arranged in series: C n H 2n O. Formic aldehyd C H 2 Ethylic aldehyd C 2 H 4 Propylic aldehyd - - 3 H 6 O Butylic aldehyd - C 4 H 8 Valeric aldehyd C 5 H 10 O OEnanthylic aldehyd - C? H14O Caprylic aldehyd - - C 8 H 16 Caproic aldehyd C 10 H 20 O Eutic aldehyd CnH 22 Ethalic aldehyd CjeH^O CnH 2n . 2 0. • Allylic aldehyd {acrolein) - C 3 H 4 C n H 2n . 4 0. Campholic aldehyd {camphor) C 10 H 16 O 86 ORGANIC CHEMISTRY. C n H 2n ^O. Benzoic aldehyd (oil of hitter almonds) C 7 H 6 O Toluic aldehyd - - - - C 8 H 8 Cuminic aldehyd - C 10 H 12 O Sycocerylic aldehyd - - - C 18 H 28 C n H 2n .. 10 O. Cinnamic aldehyd (oil of cinnamon) - C 9 H 8 0. Aldehyds may be regarded as bodies built upon the type of one or more molecules of hydrogen, in which one half the hydrogen atoms are replaced by one or more molecules of an oxidized carbohydride. The formation of aldehyd, ($Zcohol dehydrogensited), may be illustrated by the following equation: C 2 H 6 — H 2 = C 2 H 4 Ethyl alcohol. Ethyl aldehyd. Aldehyds are obtained by the oxydation of alcohols, but they are only the first products of oxydation. They are capable of combining with an additional molecule of oxygen, forming acids; hence the aldehyds are inter- mediate between alcohols and acids. ORDINARY ALDEHYD. C 2 H 4 O=0 2 H 3 O 'H This substance is formed by the slow oxydation of alcohol. ALDEHYDS. 87 Alcohol is treated with, a mixture of manganese binoxide, or of potassium bichromate, and sulphuric acid, and distilled, care being taken to keep the re- ceiver well cooled. Besides aldehyd, acetyl, acetic ether, acetic acid and water are formed. The product is again distilled, care being taken to collect only that portion which passes over above 60°. This liquid is mixed with ether, and, when cool, a stream of dry ammonia gas is caused to pass through the solution. Crystals of ammonium aldehyd are formed, C 2 H 3 (]S T H4)0, which are decomposed by dilute sul- phuric acid. The mixture is then distilled. Aldehyd is a colorless, very volatile liquid. It is soluble in water, alcohol and ether, and possesses a strong, somewhat stifling odor. The salient property of aldehyd is its avidity for oxygen. If a few drops are poured into water the latter becomes acid; it is therefore a valuable reduc- ing agent. If aldehyd, or ammonium aldehyd, VrVr f is poured into an ammoniacal solution of silver nitrate, on slightly elevating the temperature, metallic silver is deposited. This silver adheres to the sides of the tube, and covers it with a mirror-like coating. This prop- erty is the basis of a process of silvering glass globes and other hollow articles of glass. Aldehyd is attacked by chlorine and bromine, and furnishes, by substitution, various products, of which Chloral C 2 HC1 3 0, is the most important. Ily. SO ORGANIC CHEMISTRY. drate of chloral, or C 2 HC1 3 + H 2 0, liasbeen prepared now for several years in very large quantities, for medicinal purposes. Its name is derived from chlor- ine alcohol. Absolute alcohol is saturated, first cold, then hot, with dry chlorine. The liquid obtained is mixed with its volume of concentrated sulphuric acid. The supernatant liquid is decanted, and distilled in an earthern retort, with one-fourth its weight of sulphuric acid. The anhydrous chloral obtained is re-distilled twice with calcium carbonate and 7 to 8 per cent, of water. The hydrate is then obtained in handsome crystals, C 2 HC1 3 + H 2 0, soluble in water. It has been known for some time that this body is decom- posed in presence of alkalies or alkaline carbonates, into chloroform and formic acid, CJBCLO + HoO + KHO = KCHO, + CHC1, + H 2 0. Potassium Chloroform, formiate. The question appeared pertinent whether a similar transformation' would be effected in the human body, under the action of the alkaline fluids there present, notably those of the blood, and thus develop chloro- form. Liebreich was the first to administer chloral, and he at once obtained the anesthetic effects of chloroform. His experiments were repeated in different countries, and hydrate of chloral soon came into general use as a hyponotic. ALDEHYDS. 89 Chloral hydrate for medical use must be crystalline and possess the following properties: it should be col- orless, transparent, and have an aromatic odor, a caus- tic taste, readily soluble in water without furnishing drops of oil, also soluble in alcohol, ether, naphtha, benzol, and carbon bisulphide; it should fuse at 56° to 58°, solidify at about 15°, boil and volatilize completely at 95°. With caustic potassa it should furnish chloro- form, and with sulphuric acid, chloral, without becom- ing brown. Its aqueous solution should be neutral and not produce any turbidity with silver nitrate and nitric acid. Exposed to the air it should not become moist. According to recent investigations by Liebreieh, (60-69-673) chloral produces the opposite physiolog- ical effects of strychnine, hence, these bodies may be used as antidotes one for the other. The remaining aldehyds are not sufficiently im- portant for a work of this scope. Camphor has al- ready been considered in connection with turpentine. 90 OEGANIO CHEMISTRY. OKGANTC ACIDS. ACIDS CONTAINING TWO ATOMS OF OXYGEN. FATTY ACID SERIES. C n H 2n 2 . Formic acid, - C H 2 2 Acetic u C 2 H 4 2 Propionic a C 3 H 6 2 Butyric a 4 H 8 O, Yaleric a C 5 H, O 2 Caproic u - C 6 Hi,0 2 (Enantlrylic u C 7 H 14 0. 2 Caprylic a _ C 8 H 16 2 Pelargonic a C 9 Hi 8 2 Capric a CioH 20 2 Laurie a O u H,A Coccinic a Ci 3 H 26 2 My ri stic « - Ci4H 28 2 Palmitic " Ci 6 H 32 2 Margaric a C 1T H 34 2 Stearic a ^18-^-36^2 Arachidic " " ^20^40^2 Cerotic " O^H^Oa Melissic " . CsqILqqO^ ORGANIC ACIDS. 93 C n H2n-2^2- Acrylic acid - O3H4O2 Crotonic " C 4 H.O a Angelic " - C 5 H 8 2 Pyroterebic " C 6 H 10 O 2 Campholic " - CioH 18 2 Moringic " • C 15 H 28 2 Physetoleic " - Ci 6 H 30 O 2 Oleic " Ci 8 H 34 2 Doeglic '' ^1Q^-B&^2 Erucic " C 22 H420 2 . C n H 2n _40 2 . Sorbic acid C 6 H 8 2 Camphic " C 10 H 16 O 2 - AROMATIC ACID SERIES. CiAn-sOa. Benzoic acid C 7 H 6 2 Toluic " C 8 H 8 2 Xylic " C 9 H 10 O 2 Cumic " C 10 H 12 O 2 Alpha-cymic acid CnH 14 2 « C n II 2n _ 10 O 2 . Cinnamic acid - - . C 9 H 8 2 Pinic " - . - C^HsqO^ 92 ORGANIC CHEMISTRY. ACIDS CONTAINING THREE ATOMS OF OXYGEN. C n H 2n 3 . Carbonic acid C H 2 3 Glycolic " - C 2 H 4 3 Lactic " - C 3 H 6 0, Oxybutyric " C 4 H 8 3 Oxy valeric " C 5 H 10 O 3 Leucic " - C 6 H 12 3 CEnanthic " C^H^Os. C n H 2n _20 3 . • Pyruvic acid C 3 H 4 3 Scammonic " C 15 H 28 3 Ricinoleic " - C 18 H340 3 . ^n-U-2n— 4^3* Ouaiacic acid 6 H 8 0, Lichenstearic " - - C 9 H 14 3 . CnH 2n _60 3 . Pyromeconic acid C 5 H 4 O s . CnH 2n _80 3 . Salicylic acid - C 7 H 6 3 Anisic " C 8 H,0 3 Pliloretic " - C 9 H :0 O, Oxycuminic " C I0 H 12 O 3 Thymotic " - - C n H 14 3 . OBGANTC ACIDS. 93 Coumaric acid - - C 9 H 8 3 . ACIDS CONTAINING FOUR ATOMS OF OXYGEN. C n H 2n 4 . Glyceric acid C 3 H 6 4 . C n H 2n _ 2 4 , Oxalic acid 0,H,O 4 Malonic u C 3 H 4 4 Succinic a 4 H 6 4 Pyrotartaric a 5 H 8 O 4 Adipic a 6 H 10 O 4 Pimelic a C? H 12 4 Suberic a C 8 H 14 4 Anchoic a C 9 H 16 4 Sebic a Ci H 18 O 4 Eoccellic u CnH 2n _ 4 4 . C 17 H 32 4 . Fumaric acid C 4 H 4 4 Citraconic u C 5 H 6 4 Terebic u O,H 10 O 4 Camphoric u Ci H 16 O 4 Lithofellic a ^20^-26^^ 94 OEGANIC CHEMISTET. CnH2 n _60 4 . Mellitic Terechrysic acid u C n H 2n _804. CflO, C 6 H 6 4 . Yeratric acid C n H 2n _io04. C 9 H 10 O 4 . Phtalic Insolinic Choloidic acid u G n H2n-14^'4- C 8 H 6 4 C 9 H 8 4 Oxynaphthalic acid Piperic " Ci H 6 4 C 12 H 10 O 4 . ACIDS CONTAINING 5, 6, 7 AND 8 ATOMS OF OXYGEN. C n H 2n _20 5 . Tartronic acid C 3 H 4 5 Malic " C 4 H 6 5 . C n H 2n _40 5 . Mesoxalic acid C 3 H 2 O g . CnH^^Os. ORGANIC ACIDS. Cholesteric acid C 8 Hi Og. CnH 2n _ 8 5 . Croconic acid C 5 H 2 5 Comenic u C 6 H 4 5 Gallic u 7 H 6 O 5 Cholalic C n H 2n _ 2 6 . C^H^C^. Tartaric acid 4 H 6 O 6 Quinic " C n H2n-40 6 . C 7 H 12 6 . Carballylic acid C 6 H 8 6 . C n H 2n _60 6 . Aconitic acid C n H 2n _ 10 O 6 . C 6 H 6 6 . Chelidonic acid C n H 2n _ 10 O 7 . 0,H 4 O 6 Meconic acid C7II4 Of Citric acid C 6 H 8 7 Mueic u C 6 H 10 O 8 . 95 Org anic acids are bodies built upon the type of one or more molecules of water , having one half the hy- drogen replaced by an organic compound radicle con- 96 ORGANIC CHEMISTRY. taining oxygen. There are some acids whose compo- sition is not definitely fixed. We shall first examine the monatomic acids, and study the other series in the order of their atomicity. The organic acids possess the general properties of the mineral acids. Many among them, like acetic acid, have a very decided action upon litmus. Generally, they are solid and crystallizable; however, formic, pro- pionic, butyric acids, etc., are liquid. Acids whose molecules are comparatively simple, are ordinarily sol- uble in water — the others are little, or not at all, soluble in this solvent. The monobasic acids are volatile, at least where their molecules are not very complex. The polybasic acids are decomposed by heat. Their salts are ordinarily crystallizable. METHODS OF PREPARATION. ' I. The acids of the so-called fatty series are ob- tained by the oxidation of the corresponding alcohol, or aldehyd, which latter is the first product of oxida- tion of the respective alcohol. C 2 H 6 + O =C 2 H 4 + H 2 0. Y Acetic aldehyd. C 2 H 4 + 0=C 2 H 4 0, Acetic acid. II. These acids are also produced by the action of alkalies upon the cyanide of the radicle appertaining to the homologous inferior alcohol. ORGANIC ACIDS. 97 (CH 3 )(m + KHO + H 2 0=NH 3 + KC 2 H 3 2 . Methyl cyanide. Potassium acetate. III. Acids are likewise formed by the union of the elements of carbon monoxide and carbon dioxide with hydrogen carbides and water. The remarkable syn- thesis of formic acid by Berthelot is, according to this method : CO + H 2 0=CH 2 2 . Pelouze has shown that heat, carefully applied to polyatomic acids, causes them to part with a certain number of molecules of water, of carbon dioxide, or of both, and furnishes acids more simple and of a lower equivalence, which he designates by the name oipyro- acids. 2C 4 H 6 6 =C 5 H 8 4 + 2H 2 + 3C0 2 . v Tartaric acid. Pyro-tartaric acid. Of all the series of acids, the most numerous and the most important are those of the so-called fatty series- We shall presently indicate the methods by which they are obtained. Their boiling point increases from 15° to 20° with each addition of Cli 2 to their molecule. Certain of their salts, those of calcium, for instance, are decom- posed by heat, furnishing compounds called acetones. 98 ORGANIC CHEMISTRY. Ca(C 2 H 3 2 ) 2 =CaC0 3 + C 3 H 6 0. Calcium acetate. Ordinary acetone. FORMIC ACID. CH,0 2 =CH O ) Q Red ants made to pass over moistened blue litmus paper produce red stains. The acid secreted by these insects was first obtained bj Gehlen, and has re- ceived the name of formic acid. I. Berthelot has obtained it from carbon mon- oxide by synthesis. II. It is prepared by distilling a mixture of 10 parts of starch, 30 parts of sulphuric acid, 20 parts of water, and 37 parts of manganese binoxide in a large retort connected with a condenser. The mass swells considerably, and at first must be heated but gently. The formic acid is distilled over and saturated with lead carbonate. The fbrmiate of lead is caused to crystallize in boiling water, then placed in a retort and decomposed by a current of hy- drogen sulphide and thereupon heated; the formic acid is then distilled off. III. One kilo of glycerine, 150 to 200 grams of water and 1 kilo, of oxalic acid are introduced into a retort and heated for 15 hours at a temperature of about 100°. The oxalic acid is decomposed, but only carbon di- oxide is disengaged. "Water is added from time to ACETIC ACID. 99 time, and the mixture then distilled until 8 litres have passed over. The glycerine remains unchanged in the retort, and can again be used. Formic acid is a colorless liquid, of a very acid re- action, a pungent odor and crystallizing at about 0° and boiling at 10i°. It reduces oxide of mercury, furnishing mercury, as a brown powder, also carbon dioxide and water. Its salts are usually soluble, though that of lead is very little soluble in cold water, but quite soluble in boil- ing water. On heating with sulphuric acid, carbon monoxide and water are formed. Experiment. — Introduce into a test-tube a small quantity of formic acid or a formiate. Add sulphuric acid and heat; a regular liberation of a gas takes place, which may be ignited, producing a blue flame. CH 2 2 = CO-f-H 2 0. ACETIC ACID. C 2 H 4 2 =C 2 H 3 0) a Sp. Gr. 1.08. Density, of vapor 30. Glacial acetic acid melts at 17° ; boils at 118°. This is the acid of vinegar, and of which it forms the essential part. It is found in the juices of many plants and in certain fluids of the body. It is formed by synthesis from methyl, sodium, or potassium for- 100 ORGANIC CHEMISTRY. miate, and by the oxidation of acetylene; also by the action of nitric acid upon fatty substances, and by the reaction of potassa upon tartaric, malic and citric acids. It is further produced : I. By the oxidation of alcohol in the following way: Wine in vats, or casks, is placed in a cellar main- tained at a temperature of about 30°; every sixth or eighth day several litres of vinegar are withdrawn and replaced by an equal quantity of wine. Pasteur has established that the oxydation of alco- hol is produced by a minute plant, the Mycoderma aceti. In fact, acetification commences only when this plant has been formed in the liquid. If its development is interrupted the oxydation stops; it renders the service of taking oxygen from the air and transferring it to the alcohol. This process is very slow. It may be rendered more rapid by pouring dilute alcohol on beach-wood shav- ings placed in barrels. The air penetrates through openings made in the lower portion. The alcohol, after having been passed over the shavings four times, will be found sufficiently acetified, if the temperature is maintained at about 25°. II. Distillation of wood. Pyeoligneotts acid. Wood is distilled in retorts , yielding vapors and gases. The former are condensed by causing them to pass through a condenser ; the gases are conducted under the retorts, where they are burned, and the heat util- ized in the distillation of the wood. The condensed liquids are water, acetic acid, wood ACETIC ACID. 101 spirit and tar ; the greater portion of the tar is me- chanically removed and the remaining liquid distilled in a water bath. The wood spirit, which boils at 63° passes into the receiver. The water and acetic acid- remaining in the retort are saturated with sodium carbonate, the product is evaporated to dryness and heated from 250° to 350° ; this temperature, while not effecting the decomposition of the sodium acetate is sufficient to carbonize the tarry substance remaining in solution. The mass is thereupon dissolved in water, filtered, and the acetate allowed to crystallize. If it is desired to obtain the acetic acid uncombined, the solu- tion of the salt is distilled with a slight excess of sul- phuric acid. The acetic acid which distils over contains 'a large amount of water. JSTormal, or anhydrous acid may be obtained from it by saturating half of the liquid with sodium carbonate, then adding the remainder to this solution; acid sodium acetate is thereby produced, which is evaporated to dryness and distilled with sul- phuric acid. This liquid, cooled with ice, gives crystals of normal acetic acid, which can be separated on de- canting the liquid, furnishing the so-called glacial acetic acid. Acetic acid is liquid above 17°; below that it crys- tallizes in handsome plates. It is a strong acid, has a pronounced odor, and is very caustic, producing blis- ters on the skin. It is soluble in water, alcohol and ether in all proportions. It dissolves resin and cam- phor, also fibrin and coagulated albumen. On uniting 102 ORGANIC CHEMISTRY. with, water it contracts in volume. A red heat de- stroys it, many products being formed; methane, acetylene, acetone, benzol, naphthalin, etc. , also car- bon, which remains in the retort. If a flask containing chlorine gas and a small quan- tity of acetic acid, is exposed to the sunlight, trichlor- acetic acid is formed, 2 Vr [• O. This experi- ment of Dumas served as a basis for the theory of substitution. Le Blanc has also obtained monochlor- acetic acid C 2 H 2 C10 j Q Thege chlorine products are reduced to the state of acetic acid by reducing agents, such as sodium amalgam in presence of water, (H 2 ) 3 +C 2 HCl 3 2 =3HCl+CoH 4 2 . In the same manner as acetic acid, heated with an excess of a base, furnishes marsh gas, trichlor, acetic acid produces trichlorinated marsh gas, which is chloroform, 2 HA+BaO=BaCO 8 + CH 4 C 2 HCl 3 2 +BaO=BaC0 3 + CHC1 3 . Perchloride of phosphorus, in the hands of Gerhardt, has become the means of an important discovery, that of acetic anhydride and in general of the anhydrides of the monobasic acids. If dry sodium acetate (3 parts) is mixed with the perchloride, or better, with oxy- VINEGAK. 103 chloride of phosphorus, (1 part), and then distilled, a chloride is obtained called acetyl chloride, C 2 H 3 0C1=C 2 H 3 CI acetyl being the radicle of acetic acid. This chloride, subjected to the action of an excess of sodium acetate, is decomposed and furnishes acetic anhydride, C 2 H s O C 2 H 3 O, (also called acetate of acetyl) or acetic oxide, which boils at 139°. Water destroys it, acetic acid being produced. Chloride of acetyl is an irritating liquid, boiling at about 158°, decomposable by water into acetic and hydrochloric acids. A derivative of acetic acid of considerable theoretical importance is cyanacetic acid C 3 H 3 N02=C 2 H 3 j n CN[ U ' a crystalline body forming salts with the metals, which have been studied by T. Menies. On acting with sul- phuric acid and zinc on cyanacetic acid, the author [82-67-69] obtained formic and acetic acids and am- monia. Yinegar. This name is given to the mixture which is obtained by the acetification of wine, whiskey, infu- sion of malt, etc. Good acetic vinegar is of an agree- able taste and aroma. Wood vinegar has a very strong disagreeable taste and odor. It is frequently 104 OEGANIC CHEMISTEY. adulterated with sulphuric acid. An addition of -j^tf of its weight of this acid is, however, not considered fraudulent, as its presence is regarded necessary to prevent moulding. A ready method of detecting mineral acids, pro- posed by M. Witz (77-75-268), is based upon the use of methyl-aniline, which undergoes no change in con- tact with acetic acid, but promptly changes to a green- ish-blue in presence of the least trace of mineral acid. "Vinegar and concentrated acetic acid are employed in medicine as stimulants. An acetate, or acetic acid, can be recognized by heat- ing it slightly with sulphuric acid and alcohol ; a fragrant odor, characteristic of acetic ether, is observed. Heated with sulphuric acid alone, the acetates liberate a vapor which has the odor of vinegar. The following reaction permits of the detection of mere traces of acetic acid; it is saturated with potas- sium carbonate and heated with arsenous oxide in a test tube; fumes and a nauseating odor are given off. The author finds that one of the simplest tests for acetic acid, is to direct a fine, yet powerful stream of water into a test-tube, containing a few drops of the liquid to be tested. The very fine, white efferves- cence resulting is entirely characteristic of this acid, none of the other ordinary acids producing the same effect. Alcohol should not be present, as it causes a similar effervesence. If the acetic acid is combined it should be set free with a strong mineral acid. By this test, ACETATES. 105 perhaps more physical than chemical, acetic acid, di- luted with 1000 parts of water, can be readily recog- nized, and with practice, one part in 1500. ACETATES. Acetic acid is monobasic; there are, however, alka- line biacetates and some basic acetates of copper and lead. POTASSIUM ACETATE. KC 2 H 3 2 = C 2 H 3 0) This salt, distilled with its weight of arsenous oxide, furnishes a very inflammable liquid, formerly called the "liquor of Cadet," and in which Bunsen has found a radicle spontaneously inflammable, cacodyl, C 4 IT 12 As 2 . Potassium acetate forms, as well as sodium acetate, an acid acetate when treated with acetic acid. It is a very deliquescent salt, difficultly crystallizable. AMMONIUM ACETATE, NH 4 C 2 H 8 2 , Is prepared by saturating ammonium carbon- ate with acetic acid. Its solution constitutes the spirit of Mindererus ; treated with phosphoric oxide it forms cyanide of methyl. There is also an acid salt, NH 4 C 2 H 3 2 C 2 H 4 2< In compounds of this character, 106 ORGANIC CHEMISTRY. acetic acid must be considered as acting the same part as the water of crystallization in salts. SODIUM ACETATE. ]STaC 2 HA+3H 2 0. This is used in preparing marsh gas and concentrated acetic acid. It is recommended by Tommase (52-72- 23), as a solvent for plumbic iodide, of which two grams are readily dissolved in 0.5 c. c. of a strong solution of sodium acetate. CALCIUM ACETATE. Ca(C 2 H 3 2 ) 2 . This salt, subjected to distillation, furnishes a liquid containing a large proportion of acetone C 3 H 6 0- ALUMINUM ACETATE. A1(C 2 H 3 2 ) 3 . This body is employed at present by dyers, as a mor- dant. It is prepared by causing aluminum sulphate to react upon lead acetate. Lead sulphate, which is insoluble, is separated on filtering the liquid. FEEKIC ACETATE. This salt {pyrolignite) has been, and is still, somewhat employed for the preservation of wood. ACETATES. 107 COPPER ACETATES. Normal acetate Cn(C 2 H 3 2 )o is called verditer. It forms beautiful green crystals (crystals of Venus), which, subjected to distillation, furnish acetic acid mixed with acetone. During this operation, a white sublimate is formed, which deposits in the neck of the retort. This latter is cuprous acetate, and is car- ried over into the receiver, oxydizes, and changes into cupric acetate, which colors the distillate blue. There remains in the retort, after this decomposition, very finely divided copper which takes lire when slightly heated in the air. Solutions of this acetate reduce the salts of the oxide, CuO, and serve to prepare the sub- oxide, Cu 2 0. A basic acetate, designated by the name of verdigris, is obtained by exposing to the air sheets of copper moistened with vinegar, or surrounded by the marc of grapes. The metal becomes covered with a greenish incrustation whose formula is, Cu(C 2 H 3 2 ) 2 ,CuO+6H 2 0. LEAD ACETATE. The normal acetate Pb(C 2 H 3 2 ) 2 is prepared by treat- ing litharge with acetic acid in slight excess. This salt, known by the name of sugar of lead, crystallizes in oblique rhombic prisms, soluble in two parts of water and eight parts of 95 per cent, alcohol. It has a sweet taste, and is very poisonous. It is employed as a re- 108 ORGANIC CHEMISTRY. agent, also to prepare aluminum acetate and lead chro- mate. In digesting acetic acid with an excess of litharge, it furnishes a hexabasic acetate of lead. If ten parts of normal acetate, with seven parts of litharge are taken and this mixture digested with 30 parts of water, there are formed minute needles of a tribasic salt Pb(C 2 H 3 2 ) 2 , Pb02, H 2 0. Finally this salt, dissolved in normal ace- tate, gives a sesquibasic acetate, which is deposited in crystals, 2(Pb2C 2 H 3 2 ),PbO,H 2 0. Goulard's exteact is a solution containing a mix- ture of normal and of sesquibasic acetate of lead, which is prepared by boiling 30 parts of water, 7 parts of litharge and 6 j^arts of normal acetate of lead. BUTYRIC ACID. C 4 H 8 2 = C4H £i0. H It is usually prepared as follows: a mixture of 10 parts of sugar, 1 part of white cheese, 10 parts of chalk, and some water, is maintained at a temperature of 30° to 35°. First, lactate of lime is formed, which causes the mass to thicken, then that salt changes into buty- rate, disengaging hydrogen and carbon dioxide. "When the mixture has become clear, the liquor is evaporated and the butyrate separated with a skimmer. This salt is decomposed by concentrated hydrochloric acid which separates the butyric acid in the form of an oil, which is distilled off. It boils at 163°. It is of a fetid odor, and soluble in water, alcohol and ether. VALERIC ACID. 109 Valerianic, ok Valeeic Acid C 5 H 10 O 2 = 5 tt f O- It can be obtained by oxydizing amylic alcohol by a mixture of potassium bichromate and sulphuric acid v or by distilling valerian root with water acidulated with sulphuric acid. The best method is to boil por- poise oil with water and lime. The oil saponifies and the valerianate of calcium alone is dissolved. This liquid is concentrated and hydrochloric acid added in excess. The valerianic acid separates out in the form of an oil which is distilled, and that portion collected which passes over at 175°. Pierre and Puchot have lately devised a process for preparing valeric acid from amyl alcohol. (3-[3] 5-40. ) BENZOIC ACID, C 7 H 6 2 . Density, 61. Density of its vapor compared with air, 4.27. Melts at 120°; boils at 250°. It is obtained by a dry, as also by a wet process. To prepare it by the former method, equal weights of sand and gum benzoin are placed in an earthen ves- sel, the mixture covered with a sheet of filter paper, which is pasted down round the edge, and a long cone of white cardboard placed over the whole. The earthen vessel is then heated over a slow fire for two hours, and when cool the cone is removed. The ben- zoic acid is found to have condensed on the interior of the cone in handsome blades, or needles. 110 ORGANIC CHEMISTRY. It is obtained, in the wet way, by pulverizing gum benzoin, mixing it with half its weight of lime, and boiling for half an hour in a cast-iron kettle, with six times its weight of water, care being taken to agitate the mixture. It is thrown upon a piece of linen and the residue treated twice with water. The liquids are reduced in volume to two-thirds that of the water used during the first treatment, then saturated with hydro- chloric acid. The benzoic acid separates out, and is recrystallized from a solution in boiling water. It is also procured from the urine of herbivorous animals. This secretion, evaporated to a small bulk and treated with hydrochloric acid, yields a deposit of hippuric acid, which, on being heated with dilute sul- phuric acid, is transformed into benzoic acid. Benzoic acid is also produced on a large scale from naphthalin. Benzoic acid crystallizes in lustrous blades, or need- les, is little soluble in cold water, quite soluble in boiling water, and still more so in alcohol and ether. On passing its vapors through a tube heated to redness, it is decomposed into benzol and carbon dioxide, C 7 H 6 2 = C 6 H 6 +C0 2 . Chlorine, bromine and nitric acid transform it into substitution products. Chlorbenzoic acid, C 7 H 5 C10. Dinitrobenzoic " C 7 E 4 (N0 2 ) 2 2 . Ammonium benzoate furnishes, on distillation, ben- zonitrile C 7 NH 9 2 = C 7 H 5 N" + 2H 2 0. The alkaline benzoates heated with chloride, or BENZOIC ACID. Ill oxychloride of phosphorus, furnish benzyl chloride, which, submitted to the action of potassium benzoate in excess, gives benzoic anhydride, 3(KC 7 H 5 2 )+P0C1 3 - 3(C 7 H 5 0C1)+K 3 P0 4 . v j Y Chloride of benzyl. 0^3*001 + KC 7 H 5 2 = C 14 H 10 O 3 + KCl. Benzoic anhydride. The rational formula of benzoic anhydride is, c,n 5 o) C 7 H 5 \ u - Calcium benzoate heated to a high temperature furnishes benzone, Ca(C 7 H 5 2 ) 2 = CaC0 3 +CO(C 6 H 5 ) 2 . Calciumbenzoate. Benzone. Benzoic acid is monobasic, and the benzoates are generally soluble. Benzoic acid taken into the stom- ach, is transformed into hippuric acid. Kolbe and von Meyer have observed that benzoic acid has antiseptic power, though less than salicylic acid, (18-[2]12-133). cinnamio acid. In certain balsams there exists an acid called cinnamic acid, whose formula is C 9 H 8 2 . It exists in the balsams of Peru, benzoin, tolu and in liquid storax. It fuses at 129° and boils at 290°. It 112 ORGANIC CHEMISTRY. has striking features of resemblance to benzoic acid, and is produced like the latter bj the oxjdation of an aldehyd. This aldehyd is the essence of cinnamon prepared by distilling cinnamon with water. POLYATOMIC ACIDS. * OXALIC ACID. Preparation. In the burdock and sorrel is found an acid salt, commonly called salt of sorrel, which is a mixture of binoxalate and quadroxalate of potas- sium. Sodium oxalate is found in several marine plants, calcium oxalate in the roots of the gentian and rhubarb, and in certain lichens. Salt of sorrel is extracted from the burdock {Prunex\ in Switzerland, and in the Black Forest of Germany, by expressing the plant, clarifying the expressed liquid by boiling with clay, and evaporating ; crystals of salt of sorrel are deposited. The oxalic acid may be obtained free by decompos- ing a solution of these crystals with lead acetate ; the oxalate of lead which precipitates is treated with a suitable quantity of sulphuric acid ; the lead is com- pletely precipitated as lead sulphate ; this is filtered off, and the liquid evaporated and allowed to crys- tallize. At present this acid is chiefly prepared by the action of oxydizing agents upon certain organic substances^ the substances best suited for this purpose are those OXALIC ACID. 113 which contain oxygen and hydrogen in the proportion to form water. One part of starch, or sugar, is boiled with eight parts of nitric acid diluted with ten parts of water, until nitrous vapors cease to be disen- gaged, and the liquid then evaporated. The crys- tals of oxalic acid which separate out are freed from the excess of nitric acid, by being several times re- crystallized in water. It is also obtained on a large scale by the action, at a high temperature, of potass- ium or sodium hydrate on saw dust. Oxalic acid has been obtained synthetically, by Drechel,on passing carbon dioxide over sodium heated to 320°. 2C0 2 +Na 2 =ISra 2 C 2 4 . Properties. — Oxalic acid crystallizes in prisms, which effloresce in the air, and which are very soluble in water and alcohol. It fumes at 9S°; at 170° to 180° it is partially sub- limed, but the greater portion is decomposed into car- bon monoxide, carbon dioxide, formic acid and water. 2(C 2 H 2 4 )=CO +2C0 2 +CH 2 2 +H 2 0. Chlorine, hypochlorous acid, fuming nitric acid and hydrogen peroxide, convert oxalic acid into carbon dioxide. Sulphuric acid causes it to split up into carbon mon- 114 ORGANIC CHEMISTRY. oxide and carbon dioxide, and this reaction is made use of in preparing the former gas. Oxalic acid is bibasic. Normal potassium oxalate, K 2 =0 2 =C 2 2 . Acid potassium oxalate, KH=0 2 = : C202. Uses. — Oxalic acid is employed in removing ink spots from cloth, and in cleaning copper. It owes these properties to the fact that it forms with iron and copper soluble salts, hence it is also employed in calico-works for removing colors. Toxic action of oxalic acid. On account of the use of oxalic acid in the arts, and its physical resemblance to certain salts, particularly to magnesium sulphate, poisoning with it has often occurred, either through design or imprudence. It acts powerfully upon the system. Tardieu. men- tions the case of a young man, sixteen years of age, who was poisoned by two grams of this substance. The symptoms observed are similar to those pro- duced by other corrosive agents; great prostration fol- lowed by unconsciousness and a persistent numbness in the lower extremities. The blood of the patient be- comes abnormally red. In cases of poisoning, the acid should be removed from the stomach with promptness, and milk of lime, or magnesium, or ferric hydrate administered. Lime is to be preferred, as it forms a salt completely insol- uble in vegetable acids. SUCCINIC ACID. 115 SUCCINIC ACID. C 4 H 6 4 = C 4 H 4 2 ) o This acid is produced by the oxydation of butyric acid, and by subjecting amber, suceinum, to dry distil- lation or by the action of iodhydric acid on malic or tartaric acids. Succinic acid crystallizes in rhomboidal prisms which melt at 180° and boil at about 235°, at a higher tem- perature they are decomposed into water and succinic anhydride C 4 H 4 3 . It is soluble in 5 times its weight of cold water, soluble in ether and very soluble in alco- hol. It is used in the artificial preparation of malic and tartaric acids. Succinic acid has been found in the fluid of the hydrocele and of certain hydatids. MALIC ACID. C 4 H 3 2 ) n This acid, discovered by Scheele in sour apples, is found in many plants ; in the berries of the service- tree, in cherries, raspberries, gooseberries, rhubarb, to- bacco, etc. Malic acid is levogjrrate, deliquescent and crystallizable; it is soluble in alcohol and fuses at about 100°. At a temperature above 130°, it is decomposed into 116 ORGANIC CHEMISTRY. various acids and especially paramalic acid, C 4 II 4 4 , which is identical with the acid of the fumaria. It is bibasic like oxalic acid, but triatomic and is dis- tinguished from this acid by not producing a turbid- ity with calcium compounds. TARTARIC ACID. This acid, obtained from wine tartar by Scheele, in 1770, occurs free and combined with potassium in many vegetable products ; in the sorrel, berries of the service-tree and tamarind, in the gherkin, potato, Jerusalem artichoke, etc. The grape is the chief original source of this acid. One method of preparing tartaric acid is to purify crude tartar by dissolving and clarifying with clay, which throws down the coloring matters: then filter- ing and adding calcium carbonate, which precipitates half of the tartaric acid as a calcium salt. 2KHC 4 H 4 O 6 +CaCO3=CaC 4 H 4 O 6 +KAH 4 O 6 +CO 2 +H 2 Hydro-potassic Calcium Calcium tartrate. Potassium tartrate. carbonate. tartrate. The solution which contains the potassium tartrate, is filtered and calcium chloride added : the remainder of the tartaric acid is thus precipitated as a tartrate and added to the preceding. TARTARIC ACID. 117 K 2 C 4 HA + CaCl 2 = CaC 4 H 4 6 + 2 KOI. Potassium tartrate Calcium tartrate. These precipitates are washed and decomposed with sulphuric acid, the calcium sulphate is filtered off, and the liquid evaporated to the point of crystallization. This acid is also called right tartaric, or dextroracemic, as it turns the plane of polarization to the right. Kistner has obtained from certain tartrates a tartaric acid which is optically inactive. This acid, called^wm- tartaric or racemic acid, is somewhat less soluble than dextrotartaric acid, while the reverse is the case with its salts. It contains, moreover, one molecule of water of crystallization, but does not crystallize, as does the dextrogyrate acid, in hemihedral crystals. Levogyrate tartaric acid is prepared by evaporating a solution of racemate of cinchonia; the levogyrate tartrate precipitates while the dextrogyrate remains in solution; or a solution of racemic acid is allowed to stand with a small quantity of calcium phosphate, and a few spores of the .Pencilium glaucwn; fermenta- tion sets in, which destroys the dextroracemic acid. Dextrotartaric acid crystallizes in beautiful oblique prisms with a rhombic base. Cold water dissolves twice its weight of this acid; alcohol dissolves it with equal facility. It is insoluble in ether. Tartaric acid melts at about 180°; and furnishes dif- ferent pyrogenous acids, chiefly: Tartaric anhydride, or Tartrelio acid, C 4 H 4 5 , and Pyrotartario acid, C 5 H 8 4 . 118 ORGANIC CHEMISTRY. Simpson synthesized pyrotartaric acid and Lebedeff has recently (60-75-100) shown that this acid is iden- tical with that obtained by heating tartaric acid. Tartaric acid does not precipitate calcium, salts. It produces a turbidity with lime water, but an excess of acid dissolves it; by these reactions it may be distin- guished from malic and oxalic acids. Tartrates. Tartaric acid is bibasic. The two tartrates of potassium are : formal potassium tartrate, IC^H^Oe Hydro " " KC 4 H 5 6 . This latter salt is obtained by purifying the tartar of wine casks, and is called cream of tartar. It is used in the preparation of black flux, white flux, potassium carbonate, and tartaric acid, also largely in baking powders. Eochelle Salt. KNaC 4 H 4 6 +4aq. This salt is a double tartrate of potassium and sodium, which was formerly much used as a purgative. It may be pre- pared by mixing in a porcelain dish, 3500 grams of water and 1000 grams of cream of tartar, this is brought to boiling and sodium carbonate added as long as ef- fervescence is produced. This solution is then filtered and evaporated until it has a density of 1.38. The salt crystallizes in regular rhomboidal prisms; it is soluble in 2J- times its weight of water, but in- soluble in alcohol. Tartar emetic. Tartaric acid forms, with bases, a EMETICS. 119 a class of salts called emetics, the type upon which they are formed being that of tartar emetic. The ordinary^ tartar emetic has been generally assigned the formula (SbO)'K=0 2 =C 4 H 4 04, in which the monad radicle stibyl takes the place of one of the basic hydro- gen atoms. It is prepared by boiling for an hour in 100 parts of water, 12 parts of cream of tartar, and 10 parts of antimony oxide. This mixture is then filtered, evaporated and allowed to crystallize. This salt crystallizes in rhombic octahedrons ; it has a me- tallic taste, a slight acidity, and is soluble in 14 parts of cold, and about 2 parts of boiling water. Crystals of tartar emetic effloresce on exposure to the air. A strip of tin precipitates the antimony as a brown powder. Tannin, and most astringents, precipitate the antimony, hence tartar emetic should not be ad- ministered in connection with this class of bodies. This salt is the most used of the antimony compounds. Feero -potassium taeteate. — Cream of tartar is di- gested with ferrous hydrate for two hours at a tem- perature of 60°. For every 100 parts of cream of tar- tar, a quantity of hydrate should be used containing 43 parts of ferrous oxide. The product is filtered, the liquid received in shallow plates, and kept at a temperature of about 45°; the salt thus crystallizes in brilliant scales of a garnet red color. It dissolves in water, but is insoluble in strong alcohol. Tartaric acid is often adulterated with alum, potassium bisulphate and cream of tartar ; these substances may 120 ORGANIC CHEMISTRY. all be detected by means of alcohol, in which they are not soluble. Tartaric acid is used in making effervescing drinks, and as a discharge by calico printers. Tartaric acid produces the same toxical effects as oxalic acid, though requiring much larger doses. The blood of the poisoned person becomes red and very fluid. CTTKIC ACID. nun — ^6H 4 3 ) ^ This acid is found associated with oxalic and tartaric acids in many plants. It occurs in cherries, currants, raspberries, oranges and lemons. It is ordinarily extracted from the juice of lemons. This juice is allowed to stand until fermentation com- mences, then filtered and treated with chalk and milk of lime ; an insoluble citrate of calcium is formed, which is decomposed by sulphuric acid; the calcium sul- phate is filtered off and the filtrate evaporated and left to crystallize. Citric acid crystallizes in regular rhombic prisms; it is soluble in three fourths its weight of cold water; this solution, in time, becomes covered with mould. Citric acid is soluble in alcohol and ether. Heated to about 175° it furnishes aconitic acid, C 6 H 6 6 = C 6 H 3 Oc }0 3 , CITEIC ACID. 121 losing H 2 on increasing the temperature. Another pyrogenous acid, itaconie acid C 5 H 6 4 is formed, which, if heated, is transformed into citraconic acid isomeric with the last mentioned. Oxydizing bodies destroy citric acid, carbon dioxide, acetone, etc., being produced. Fused caustic potassa resolves it into acetic and oxalic acids. C 6 H A + H 2 0=C 2 H 2 4 + 2C 2 HA • Oxalic acid. Acetic acid. Citric acid is tetratomic and tri basic. It may be distinguished from oxalic and tartaric acids by its ac- tion on lime water, which it does not precipitate in the cold, but if boiled with an excess of lime water, a pre- cipitate of basic calcium citrate is obtained. Magnesium citeate. — This salt is prepared by treat- ing magnesium carbonate with a strong solution of citric acid and precipitating this salt with alcohol. It is much used in medicine as a purgative. Citrate of iron. — Hydrated ferric oxide is dissolved in a luke-warm solution of citric acid, and the liquid evaporated to dryness. This body varies in its composition ; it occurs in brilliant amorphous scales, of a garnet-red color. Ammonia cerate of iron. — One hundred grams citric acid are digested for some time with a quantity of ferric hydrate, representing 53 grams of iron, and 16 to 20 grams of aqua ammonia. The liquid is then filtered and evaporated to the consistency of a syrup, 122 ORGANIC CHEMISTRY. and transferred to very shallow vessels which are placed in drying ovens. This substance solidifies in scales, if the temperature at which it is dried is not too high and the layers of liquid are extremely thin. LACTIC ACID. C 3 H 6 3 = C 3 H 4 ) g H.H \ U ' This acid was discovered by Scheele, who extracted it from sour milk. It exists in many products after fermentation, as sauerkraut, beet juice, and various vegetables, also nux vomica. It is found in many ani- mal fluids, in the blood and in the fluids which per- meate the muscular tissues. It is to this body that the acid reaction of sour milk is due. Lactic acid extracted from flesh forms, with certain bases, salts which differ in solubility, etc., from those formed with ordinary lactic acid, hence this acid is sometimes called paralac- tic acid, also sarko-lactic acid, from Gapxo* flesh. Lactic acid may be prepared by dissolving sugar of milk in butter-milk, adding chalk to the mixture, and allowing it to stand for eight or ten days at a tem- perature of 30° to 35° The sugar of milk is sometimes replaced by glucose, or cane sugar and fermentation favored by the addi- tion of cheese. A special ferment (lactic ferment) is developed which is transformed into sugar and lactic acid, but the fermentation is arrested as soon as the liquid LACTIC ACID. 123 becomes acid, and it is in order to prevent this acidity that an excess of calcium carbonate or sodium bicar- bonate is always maintained. Wurtz has produced this acid artificially by the action of platinum black on propylglycol. O a + CsIIsO.^CsHA + H 2 0. Propylglycol. Lactic acid is a colorless, syrupy liquid ; at about 130° it is changed into the anhydride of lactic acid, C 6 H 10 O 5 , and at about 250° it furnishes a crystalline body called lactide whose formula is C 3 H 4 2 . Lactic acid posseses the property of dissolving cal- cium phosphate. The lactates are soluble in water. Lactate of iron, (C 3 H 5 3 ) 2 Fe, is employed in medicine. URIC OR LITHTC ACID, (^H^N^Oa. Discovered in 1716, by Scheele. This acid exists in human excretions, and in those of the carnivora. In the excretions of herbivora, the uric acid is replaced by hippuric acid. Uric acid is present in normal human urine only in small quantity. The urine of sedentary persons, and of those whose food is very nitrogenous and quite substantial, contains more of this substance than that of individuals who lead an active life, and whose diet is less nourishing. In the latter case the uric acid is oxydizecl and converted into urea, hence, the proportion of the acid decreases as the quantity of urea increases : whereas calculi of 124 OEGANIC CHEMISTEY. uric acid are frequently formed in persons whose diet is very nourishing, and whose occupation necessitates but little muscular exertion. The excreta of birds contains a large proportion of uric acid, and that of snakes is formed almost exclusively of this body. This acid may be prepared by boiling a dilute al- kaline solution with guano, excreta of the boa con- strictor, or uric calculi finely pulverized. The liquid is filtered and the filtrate supersaturated with hydrochloric acid ; the uric acid precipitates in flakes, which become crystalline on standing. The author having had occasion in 1858 to prepare large quantities of uric acid from guano, found that in order to obtain the purest product, as free from color- ing matter as possible, it was preferable to use sod- dium hydrate as a solvent, and carbon dioxide as a pre- cipitant, the latter in sufficient excess to transform the hydrate into bicarbonate. . Crystals of uric acid are colorless and odorless. They are nearly insoluble in ether and alcohol. About 1500 parts of boiling water are necessary to dissolve one part of the acid. ' On distillation uric acid yields urea and other cy- anic compounds. Uric acid heated with water and lead dioxide furnishes urea and a substance called al- lantoin, which has been found in the urine of sucking calves. Its formula is C 4 H 6 E" 4 3 . The same derivative of uric acid was obtained by the author in 1858, also parabanic acid, on heating uric acid with manganese dioxide and sulphuric acid. (80-[2]44-218.) URIC ACID. 125 If 1 part of uric acid be added to 4 times its weight of nitric acid of a specific gravity of 1.45, the solution being kept cool, small crystals of a substance called alloxan separate out, whose formula is C 4 H 4 lSr 2 5 +3H 2 0. Woehler and Liebig obtained from this body a num- ber of very interesting derivations, alloxantin, al- loxanic acid, parabanio acid, thionuric acid, dia- luric acid, and finally a magnificent purple crystalline body, murexide. A large number of various deriva- tives have also been obtained by other chemists, especially Bayer. The rich color, murexide, is made use of in detecting uric acid. For this purpose, traces of uric acid are heated in a watch glass for a few minutes, with one or two drops of nitric acid ; the ex- cess of acid is evaporated, and the dry residue exposed to the vapors of ammonia, when a purple, or very beautiful rose color, will appear. HIPPURIC acid. C 9 H 9 N0 3 . The urine of herbivora contains a large percentage of this acid, which also exists in a small quantity in human urine. A frugivorous diet augments the pro- portion of this body. It is prepared by boiling the fresh urine of the horse (hence the name, from innos, a horse), or better from that of a cow, with milk of 126 ORGANIC CHEMISTRY. lime, which is then filtered and evaporated to one- tenth its volume; this is mixed with a large excess of hydrochloric acid and left to stand 10 or 12 hours. The impure hippuric acid which precipitates is re-dis- solved in soda and re-precipitated with hydrochloric acid. Animal charcoal may be added to the saline so- lution if the brown color still remains. Putrid urine yields only benzoic acid. Dessaignes has prepared this acid artificially by causing zincic glycocol to act on benzoyl chloride. Zn(C 2 H 4 N0 2 ) 2 + 2C 7 H 5 0C1= ZnCl 2 + 2C 2 H 3 [NH(C 7 H 5 OJ0 2 . Hippuric acid crystallizes in colorless crystals, Avhich require 600 parts of cold water for their solution, but are very soluble in hot water and alcohol. It is decomposed at 240°, benzoic and cyanhydric acids being found among the products of distillation. Under the action of oxydizing agents it furnishes ben- zoic compounds; with nitrous acid it yields benzo-gly- colic acid. ALKALOIDS. 127 ALKALOIDS. ARTIFICIAL BASES OK ALKALOIDS. PRIMARY. C n H 2n+3 N. Methylamine - - - CH 5 N Ethylamine - - - C 2 H 7 E" Propylamine - - ■ - C 3 H 9 N Butylamine - C 4 H n lS" Amylamine - - - C 5 H 13 N Caprylamine - - - 8 H 19 ]Sr. 4 c n H 2n+1 isr. Acetylamine - C 2 H 5 N Allylamine - - - C 3 H 7 N. Plienylamine, aniline - - C 6 H 7 N Toluidine - C T H 9 N Xylidine - C 8 H U N Cumidine - C 9 H 13 N. C n H 2n _ 7 K Phtalidaimne - - - (lEUST. 128 ORGANIC CHEMISTRr. C n H 2n _ n K Naphthalamine - (WN. SECONDARY. Dimethylamine Methylethylaraine - Diethylamine C 3 H 9 N C 4 H n K TEENAEY. Trim ethylamine Dimethylethylamine Methylethylamylamine C 3 H 9 ^ C 4 H n ^ C 8 H 9 K PHOSPHINES. Methylphosphine Dimethylphosphine Trimethylphosphine - CH 5 P • C 2 H 7 P C 3 H 9 P. AESINES. Triethylarsme C 6 H 15 As. STIBINES. Triethylstibine 6 H 15 Sb. NATURAL ALKALOIDS. 129 PKINCIPAL NATUKAL ALKALOIDS. OF THE CINCHONAS. Quinia,Quinicia and QumidiaQjoHyN^ Cinchonia and Cinchonidia O20H24N2O Aricina - - - CasH-j^C^. OF OPIUM. Morphia - c 17 H 19 isro3 Codeia - - C 18 H 21 N 3 Thebaia - C 19 H 21 N0 3 Narcotina - - cano 7 Papaverine - - CA^o 4 Narceia - - C23H29N 9 . OF THE STEYCHNOS. Strychnia - - CaHaNA Brucia - - CJE{ 2 qN 2 0^ OF THE SOLANACE^E. Nicotina - CioH 14 E"2 Atropia - - - 0„H a N 3 Hyosciamine - OnHaNO, Solania - - C 43 H n N 16 . OF THE HEMLOCK. Conylia - - - C 8 H 15 N. 130 OEGANIC CHEMISTRY. OF PEPPER. Piperidine - - - C 5 H U K MISCELLANEOUS. Aconitina - - - C 2T H 40 1^ O Yeratria - - - C 32 H 52 K 2 8 Theobromine - - C 7 H 8 N 4 2 Caffeia - - - C 8 H 1Q N 4 2 . The first organic base isolated was morphia, obtained in 1816, by Sertuerner. In 1819, Pelletier and Ca- ventou extracted quiniafrom cinchona bark, and showed that the very active plants used in pharmacy owed their energy to compounds capable of uniting with the acids, and of forming with them definite crystallizable salts. From that epoch, the number of organic alkaloids has become very considerably augmented ; and methods have been discovered by which many of the alkaloids are prepared artificially, It was Fritsche who, in 1840, obtained the first artificial alkaloid on distilling indigo with potassa ; he named it aniline. Gerhardt by similar methods prepared quinoleine, Cahours piperidine, and Chantard toluidine. The distillation of organic matter also furnishes al- kaloids. Thus several of them have been obtained from a product of the distillation of bones, the oil of Dippel ; also as products of the distillation of various other organic compounds. COMPOUND AMMONIAS. 131 A very general method is due to Zinin, which, con- sists in causing a reducing substance to act upon nitrous compounds as nitrobenzol, for example. The nitrous compound is introduced into an alcoholic solu- tion of ammonium sulphide, and the mixture allowed to stand ; sulphur is soon deposited, and the hydrogen of the hydrogen sulphide combines with the oxygen of the nitrous compound. Example: C 6 H 5 N0 2 + 3H 2 S=2H 2 + 3S + C 6 H 7 K Nitrobenzol. Aniline. For this mode of reduction, as it is not very prac- tical, and is tedious in execution, there is at present substituted the action of iron upon acetic acid, or that of zinc or tin, on hydrochloric acid. Wurtz has given a very interesting method, which has led to the discovery of alkaloids much resembling ammonia, for that reason called compound ammonias. It consists in causing potassa to react upon the cyanic ethers, these bodies being decomposed much like cy- anic acid. Thus methylamine is obtained by the action of potassium hydrate upon cyanate of methyl : CO ) 0H s| ^ s Vn+2Kho=k 2 co 3 + h [isr. Cyanate Potassium Methyl- of methyl. carbonate. amine. Hofmann made known, very shortly after the pub- 132 ORGANIC CHEMISTRY. lication of "Wurtz' process, a method for the prepara- tion of the compound ammonias, by which not only a simple equivalent of hydrogen is replaced by the radicles (CH 3 ), (C 2 H 3 ), etc., but all the hydrogen of the ammonia. Hofmann's method consists in causing ammonia to react upon hydrochloric as well as brom- hydric or iodhydric ethers, particularly the latter. Let us take, as an example, iodide of ethyl in con- nection with the study of ETHYLAMINE. Ten to 15 grams of iodide of ethyl and 50 grams of aqua ammonia are heated in sealed tubes of green glass placed in a water bath. The following reaction occurs: C 2 H 5 I + ]SrH 3 =C 2 H 8 NL When the liquid has become homogeneous it is allowed to cool, then decomposed by a solution of po- tassium h} r drate, the vapors being collected in water, containing hydrochloric acid. The hydrochloric acid solution is evaporated to dryness, and the residue treated with pure alcohol, which dissolves the chlorhydride of ethylamine and leaves in an insoluble state the ammo- nium chloride derived from the excess of ammonia used. The solution of chlorhydride of ethylamine is evaporated to dryness, and the deliquescent crystals obtained decomposed by potassium hydrate, with the aid of a gentle heat. The volatilized product is con- densed in a cooled receiver. In this reaction there is CLASSIFICATION OF THE ALKALOIDS. 133 also formed diethylamine, triethylamine and oxide of tetrethylammonium from which the ethylamine is separated by distillation. It may be obtained more readily by first distilling 1 part potassium cyanate with 2 parts potassium siilphovinate, then by decomposing the cyanic ether obtained with a boiling solution of potassium hydrate contained in a flask connected with a cool receiver. Ethylamine is a limpid liquid, with a strong odor resembling that of ammonia. It has not been solidi- fied. It boils at 18. 7°, and dissolves in water, producing a very caustic solution. Ethylamine is equally soluble in alcohol and ether. It is combustible, burning with a blue flame, yellow at the margin. It displaces ammonia from its combinations. Its solutions give reactions similar to those of ammonia; for instance, with salts of copper it gives a bluish white precipitate, which is dissolved in an excess producing a deep-blue solution. It differs from ammonia in the following reaction: ethylamine precipitates alumina from its salts, and the precipitate is soluble in an excess of ethylamine, which is not the case with ammonia. CLASSIFICATION OF THE ALKALOIDS, OK OKGANIC BASES. Amines. — Hofmann has given the names of primary amines, or monamines, to ethylamine, which we have just studied, and the compound ammonias in which a single atom of hydrogen has been replaced by a radicle. 2 H 5 ( a H 5 K +CJ3£= =N- 2 H 5 ,H1 H H 134 ORGANIC CHEMISTRY. The same chemist, having prepared ethylamine by the action of ethyl iodide upon ammonia, subse- quently succeeded in obtaining diethylamine by similar means. The reaction is the following : N This hydroiodide obtained, treated with potassium hydrate or lime, furnishes a second base, which is biethylammonia, or diethylamine ; Diethylamine C 4 H 11 ^"=:]Sr A similar compound is, f H TT Ethylaniline C 8 H n N=N"^ C 3 hJ. l-H These bases have been given the name of secondary amines or imides. The secondary ammonias are attacked by ethyl iodide and other ethers, and a reaction takes place, iden- tical with that which gives rise to the primary and secondary amines and tertiary amines, also called nitrile bases, are thus obtained. AMINES. 135 Such bodies are: fC 2 H g Trietkylamine C 6 H 15 N=:N^ C 2 H 5 . tC 2 H s fCH 3 Methylethylphenylamine C 9 H 13 N=N^ C 2 H 5 . IC 6 H 5 These bases are related to the alcohols in the same manner as the primary amines. Thus diethylamine is derived from the action of 2 molecules of alcohol on 1 molecule of ammonia and the elimination of 2 mole- cules of water: 2(C 2 H 6 0) + NH 3 -2H 2 0=C 4 H u ]Sr. In like manner the ternary amines may be consid- ered as derived from 3 molecules of alcohol and 1 mole- cule of ammonia with the elimination of 3 molecules of water. There are also bodies built upon the type of two and three condensed molecules of ammonia, and are denominated, respectively, di-amines and tri-amines; as ( (C 2 H 4 )" Secondary ethylene diamine N 2 < (C 2 H 4 )' ; , H IT 4 ' Ternary ethylene diamine N 2 •< (C 2 H4)\ I (0 2 H 4 )" 136 ORGANIC CHEMISTRY. Trieth ylamine attacks hydroiodic ether, and there is formed the compound C 8 H M NI=]S"(C 2 H 5 ) 4 L This body treated with oxide of silver, furnishes an oxy- genated quaternary base, CsH^JSTI + Ag HO=Ag I + C 8 H 21 NO. This substance is very caustic, soluble in water and acts as an in organic alkaline base like potassium hydrate, with which body it is also analagous in com- position. KJ Q (W| a Amides, Alkalamides. — The amides are bodies built upon the type of ammonia, in which one or more of the hydrogen atoms are replaced by an acid compound radicle; thus, ( C 2 H s O acetamide IIH . (H There are also mixed combinations of amides and amines, called alkalamides, as C 6 H 5 acetanilide N" ■{ C 2 H 3 0. H ALKALOIDS. 137 JSTATUEAL ALKALOIDS. Many of the natural alkaloids appear to possess a composition analogous to that of the compound am- monias. Some are not attacked by iodide of ethyl, and should be classified among the ammoniums, bodies having the same relation to the compound ammonias as does ordinary ammonium hydrate to ammonia. Others are acted upon by iodide of ethyl, and, from the number of bases furnished, it may be ascertained whether they belong to the primary, secondary or ter- nary compound ammonias. The properties of the natural alkaloids in general, resemble those of the artificial bases or alkaloids. They contain nitrogen ; those that do not contain oxy- gen are ordinarily volatile, while those with oxygen are non- volatile ; they are very soluble in alcohol, ether and chloroform. Certain ones are dissolved by the hydrocarbides, which are now considerably used in the preparation of the alkaloids. Water does not dissolve any of the artificial alkaloids, except those having a very low molecular weight, like ethylamine; this liquid, how- ever, dissolves codeia and narceia quite readily. With the exception of quinia and cinchonia, they turn the plane of a polarized ray of light to the left. They react like ammonia, or potassa, with vegetable 138 ORGANIC CHEMISTRY. colors, and furnish, with platinum bichloride, crystal- lizable double chlorides, little soluble and yellow in color. They combine equally well with auric and mer- curic chlorides. The natural alkaloids have ordinarily a bitter taste. Among their salts the sulphates, nitrates, chlorides and acetates are mostly soluble, while the oxalates, tartrates and tannates are insoluble. The harmless character of tannic acid, and the in- solubility of the compounds formed by it, with the al- kaloids, render tannin and astringent vegetable sub- stances generally very efficacious antidotes. The precipitates they produce are soluble in acid and alkaline liquids. The alkaloids are partially precipitated from their solutions by potassa, soda and ammonia. Iodine water and solutions of iodine in potassium iodide, precipitate them completely. According to Schultze, the liquid obtained by add- ing antimony perchloride to a solution of phosphoric acid, is a re-agent which precipitates most of the or- ganic bases. A delicate re-agent for the alkaloids is the double iodide potassium and mercury. According to Meyer, the best proportions are 49 grams of potassium iodide and 135 grams of mercury dichloride, to 1 litre of water. It is best to add the re-agent to xhe solution of the alkaloid, which may be neutral, acid, or even feebly alkaline. It must be borne in mind that the presence of NICOTINA. 139 sugar, tartaric acid and of albumen may mask the reac- tions of a number of alkaloids. NICOTINA OR NICOTYLIA. C 10 H 14 N 2 . Nicotina is obtained from tobacco (Nicotina taba- cum.) For this purpose a decoction of tobacco is made, and the liquor evaporated to a syrup. The extract is treated with twice its volume of 85 per cent, alcohol, which precipitates the salts present and certain organ- ic substances. . The alcoholic solution is distilled and the residue submitted to a second similar treatment. The alco- holic extract thus obtained, is mixed with a concen- trated solution of potassium hydrate, and the nicotina liberated is re-dissolved in ether. This ethereal solu- tion is evaporated in a water bath, and the residue distilled in an oil bath, in an atmosphere of hydrogen. Nicotina is a colorless liquid when pure, remaining liquid at -10°, boiling at about 215°, with decomposi- tion. It has the odor of an old pipe. Exposed to the air it becomes brown, then resinous; water, alcohol and ether dissolve it ; its solutions are strongly levogyrate. Nicotina is a powerful base; it fumes when a rod moistened with hydrochloric acid is brought near it; it precipitates the metallic oxides. Nicotina requires two molecules of a monobasic acid for saturation. The chloride, C 10 H 14 N 2 ^HC1, is crystallizable, though 140 ORGANIC CHEMISTRY. deliquescent. The hydrogen it contains is not replace- able by methyl, ethyl, etc. It may be considered as having the rational formula, iri( 2*3". CD p so So . on S3 Wheat, ,14.0 59.5 7 1.7 14 1.2 i.5 Eye, 16.0 57.5 10 3.0 9 2.0 2.0 Oats, 14.0 53.5 8 4.0 12 5.5 4.0 Bice, 14.5 rr.o 0.5 7 0.5 0.7 The sticky, elastic substance found with starch in flour is gluten (called also glutin), and is a mixture of various proximate compounds, but chiefly of three; legumin, or vegetable casein, fibrin and gelatine. Flour of good quality is dry and soft to the touch; it forms with water an elastic, non-adhesive dough. The value of flour depends largely upon the gluten it contains, though not as stated in most authors upon the percentage of this substance, but upon the quality rather, as shown by recent investigations of R. "W. Kunis (26-74-1487). The modern "patent process," originating in Min- nesota, is mainly a method of grinding which intro- duces into the flour more gluten than in older pro- cesses. GUM. CfiHmOt;. This substance is very widely distributed in the vegetable kingdom. Gums either swell in water or GUM. 217 are dissolved, imparting to it a mucilaginous consis- tency. From a chemical standpoint they are essentially characterized by giving a precipitate of mucic acid on being boiled with nitric acid, and by precipitating lead subacetate. Gum-arabic, ARABiN. This gum exudes from dif- ferent species of acacias, as Acacia arahica, A. sene- galensis, A. vera / it is obtained from Arabia and Senegal. According to Fremy, gum-arabic is a salt formed by the combination of an acid, gummic or arable acid, with lime and potassa. This acid may be isolated by pouring hydrochloric acid into a solution of gum, and adding alcohol; an amphorous deposit is formed which, dried at 120°, has the formula C 6 H 10 O 5 . This acid is very soluble in water. Its solution is levogyrate, like that of gum-arabic. On being heated to 150° it is transformed into a substance insoluble in water called meta-gummic acid, whose salts are likewise insoluble. Gum-arabic gives with ferric salts an orange-colored, floculent precipitate soluble in acids. Ceeasin. The gum which exudes from cherry and plum trees is a mixture of soluble gummates and in- soluble meta-gummates ; hence it is only partially soluble in water. Cerasin becomes soluble on being boiled with water, as the meta-gummates are transformed into gummates by the action of boiling water. These gums heated with dilute sulphuric acid furnish a dextrogyrate sugar. 218 OEGANIC CHEMISTEY. Gum-tragacanth often contains starch. Mucilage or Bassorin. There exists in the seeds of the quince and flax, in the roots of the marsh-mal- low and in portions of many other plants, a substance or substances, which, exposed to the action of boiling water, furnish a thick mucilage, which appears to con- sist of a soluble, together with an insoluble substance. Nitric acid converts this mucilage into mucic and ox- alic acids. Gum and mucilage are frequently em- ployed as emollients, and in syrups, also extensively in confectionery. Pectin Group. Many roots, as the carrot, beet, etc., also green fruits, contain a neutral gelatinous substance, insoluble in water, alcohol and ether, called pectose. It is that which gives to green fruits their harshness. This substance is modified during the ripening of the fruit and becomes soluble, vegetable jelly, or pectin (from ar/KriS, a jelly), to which Fremy assigns the formula C 32 H 48 3 2. Pectinj submitted to the action of a ferment found in the cellular tissues of vegetables, called pectase, or of cold, very dilute, alkaline solutions, is changed into a gelatinous acid called pectosic acid, then into another substance likewise gelatinous, which is known by the name of pectie acid. All these substances are amorphous, and non -nitrogenous. Their formulae are not yet definitely determined. According to Fremy, to whom we are indebted for the foregoing facts, the jelly obtained from the current and other fruits is due to the action of the pectase on the pectin of these fruits. LEGUMHST. 219 These substances resemble gums in producing, on boiling with nitric acid, a precipitate of mucic acid. Much doubt still exists respecting the composition of the pectin group. LEG-UMIN OR VEGETABLE CASEIN. Legumin is found in most leguminous seeds, such as sweet and bitter almonds; also in beans, peas, etc., the latter containing about 25 per cent. It is con- sidered to be identical with casein by Liebig and Wbehler. It may be obtained by digesting coarsely powdered peas in cold or tepid water for two hours, allowing the starch and fibrous matter to subside^ and then filtering the liquid. It forms a clear, viscid solution, which is not coagulated by heat unless albumen is also present, but, like emulsin and unlike albumen, it is precipitated by acetic acid. It is coagulated by lactic acid, also by alcohol; in the latter case the precipitate is redissolved by water. Acetic acid, diluted with 8 to 10 parts of water, is carefully dropped into the filtered solution obtained above, and the legumin is precipitated; an excess of the acid should be avoided, as this would dissolve the precipitate. It falls in the shape of white flakes, and after having been washed on a filter should be dried, pulverized and freed from adhering fat by digestion in ether. Legumin may be obtained from lentils with the same facility as from peas; but it is 220 ORGANIC CHEMISTRY. less easily procured from beans (haricots), in con- sequence of their containing a gummy matter which interferes with its precipitation and with the filtration of the liquids. The chemical properties of legumin are identical with those of casein. Liebig supposes that grape-juice and other vegetable juices which are deficient in albumen, derive their fermentation power from soluble legumin. This principle is soluble in tartaric acid, and to its presence he ascribes the tendency of sugar to form alcohol and carbon dioxide instead of mucilage and lactic acid. VEGETABLE ALBUMEN. Vegetable albumen is contained in many plant- juices and is deposited in flocculi on applying heat to such liquids. It can also be precipitated by nitric acid, tannin and mercuric chloride precisely like animal albumen. Vegetable albumen is composed of carbon, hydrogen, nitrogen, oxygen and sulphur. There is no trustworthy formula for this substance. ANIMAL CHEMISTRY ANIMAL CHEMISTRY. The substances serving as materials to build up the structure of animals are of a varied nature ; they may, however, be grouped into four classes : I. FARINACEOUS AND SACCHARINE. II. FATTY. III. NITROGENOUS. IV. MINERAL. We have already studied the first, second, and fourth of these classes ; we will now proceed to examine those of the third. NITBOGKENOUS SUBSTANCES. It is generally considered that these substances act a different part in the organism from that of the saccharine and fatty bodies, these latter serving ex- clusively as heat producers, and being decomposed and ultimately consumed (oxidized) in the respiratory process, have therefore received the name of respiratory foods. The nitrogenous principles (albumen, casein, fibrin, etc.) serving to form the tissues have, likewise, 224 ANIMAL CHEMISTRY. received the denomination plastic foods. The distinc- tion thus made is too restricted, as we shall show later. Dumas and Oahours have proven that the cereals and other plants employed as food contain similar principles to those found in flesh, and especially that albuminoid matter exists in plants as well as animals. The albumen of the blood and that of wheat are alike. In the gluten of wheat albuminoid substances are found which are hardly distinguishable from animal albumen, fibrin, and casein. These substances are characterized : 1st. By their amorphous structure. The three sub- stances mentioned never crystallize ; and as they are also non- volatile, it is difficult to form an idea of their constitution, and represent them by a formula. This formula must necessarily be very complex, as sulphur forms a constituent, though present only in very small quantity. Lieberkuhn represents their composition by the expression C 72 H 112 N 18 S0 22 . 2nd. By their extreme instability. The apparently most insignificant circumstance causes them to pass from a soluble to an insoluble condition, or vice versa, and produces their transformation. They are decom- posed with great facility under the action of air and water. This very exceptional instability constitutes a property of the greatest interest, as it permits these NITROGENOUS SUBSTANCES. 225 substances to take part in a wonderful manner in the varied transformations which occur in living organisms, and it might be said that they are the principal agents of development in animals and plants. We shall pre- sently see that, whatever this real albuminoid sub- stance may be, it is transformed in the stomach into identical substances — peptones; also, that during the incubation of the egg the albumen is seemingly changed into fibrin. Classification. — The albuminoid substances are very numerous, and may be classed into two groups. Those of the first group contain : Carbon . . . . .53.5 Hydrogen 6.9 Nitrogen . . . . .15.6 Oxygen 24.0 100.0 They contain, besides, 0.4 to 0.5 per cent, of sulphur, unlike those of the second group, which usually contain no sulphur. In addition, they often contain small quantities of mineral substances. The first are more specially designated by the name of albuminoid substances, as albumen is the most characteristic member of the group. They are also known by the name of protein substances, because Mulder claimed they might be considered as formed of a single radical protein, to which are united variable proportions of sulphur, phosphorus, etc. 226 ANIMAL CHEMISTEY. The principal members of this group are : albumen, of which several modifications are recognized — the paralbumen, metalbumen, etc. ; fibrin, of which there are several kinds — the fibrin of the blood, fibrin of the muscles or myosin ; casein, regarded by some as a com- bination of albumen and alkali ; hemoglobin or hemato- crystallin, the colouring matter of the blood, which is distinguished from most other albuminoid substances by its property of crystallizing ; vitellin, the principle of the yolk of an egg ; also, several principles, icthin, icthlin (IxQvs, a fish), emydin, the first two obtained by Valenciennes and Fremy from fishes' eggs, the latter from the eggs of the turtle. The composition of these substances is identical or very similar; a formula cannot be given with pre- cision. The substances of the second group generally contain less sulphur, often none, and appear to be derived from the first by the addition of nitrogen and oxygen. They contain in per cent. : Carbon . . • . . . 50.0 Hydrogen . . • . 6.3 Nitrogen 16.8 Oxygen ;--...... 26.6 100.0 In this group we find — ossein, the organic substance of bones, which is converted into gelatin by the action of boiling water ; cartilage, a substance very analogous NITROGENOUS SUBSTANCES. 227 to the latter, and which is transformed by boiling water into chondrin ; various principles concerned in the digestive phenomena, as the ptyalin of the saliva, the pepsin of the gastric juice, the mucin of the mucus, the pyin of pus, etc.; together with different pro- ducts which result from the action of the gastric juice upon nitrogenous substances, and which are called albuminoses or peptones. General Characteristics. — The substances of these two groups on being heated give off an odour of burnt feathers. On distillation they produce water, empy- reumatic oils, and ammonium carbonate, sulphide, and cyanide. Carbon remains in the retort. The substances of the first group, on being heated to 50° — 60° with a solution of potassium hydrate, lose their sulphur and are dissolved. If we add acetic acid to this liquid, dark grey flakes of a substance (protein of Mulder) are thrown down. The substances of the second group do not possess this property. On pro- tracted boiling with a caustic alkali they yield : Tyrosin . „ . . C 9 H n NO s Leucin .... C 6 H 13 N0 2 Glycocol .... C 2 H 5 N0 2 Some are soluble, others insoluble, in water ; they are, in general, insoluble in alcohol, ether, and chloroform. Hydrochloric acid diluted with 1,000 times its weight of water dissolves some, a few swell up simply ; upon others it has no effect. Hot concentrated hydrochloric 228 ANIMAL CHEMISTRY. acid attacks all these substances, and the resulting pro- ducts are the same as those which are obtained (and more readily) with sulphuric acid. These products are chiefly glycocol, leucin, and tyrosin. Nitric acid colours them yellow (xanthoproteic acid). Ordinary phosphoric and acetic acids do not precipitate the substances of the second group, but redissolve them even when coagulated. Solutions of albuminoid substances in potassium hydrate do not precipitate copper salts. Heated with oxidizing reagents, as a mixture of potassium bichro- mate and sulphuric acid, they furnish several members of the series of fatty acids, and the aldehyds corre- sponding to these acids. The albuminoid substances are decomposed during the process of respiration in the same manner as when under the action of oxidizing agents. Ammoniacal solutions of copper dissolve albuminoid substances as they dissolve cellulose, which fact would seem to connect the albuminoid substances with cellu- lose, and to give certain weight to a theory of Hunt, which considers the albuminoid substances as cellulose which has combined with the elements of ammonia and parted with the elements of water. ALBUMEN. This substance is found both in vegetable organisms (cereals) and in animal organisms (serum of the blood, white of egg, lymph, chyle). ALBUMEN. 229 Wurtz obtains it by mixing white of eggs with twice its weight of water, straining and precipitating the albumen with a solution of lead acetate. The precipitate is washed with cold water and decomposed with a current of carbon dioxide, which precipitates the lead, while the albumen remains in solution. If this liquid be evaporated at a temperature below 59°, it is deposited in a soluble state ; if a quantity be heated to 63°, a portion of the albumen is coagulated ; but if the temperature is not raised above 74°, four-fifths remain dissolved ; consequently it would seem as though there were several kinds of albumen, but the nature and amount of foreign substances present are the principal causes of these differences. If the solution is very dilute, coagulation will not take place. Heating is not the only mode of producing this change ; alcohol, acids — with the exception of a few, such as hydrogen phos- phate, H 3 P0 4 , hydrogen tartrate and hydrogen acetate — the metallic salts, creosote, tannin, etc., also effect it. The alkalies prevent this action. Gautier obtains albu- men by dialysis. Soluble albumen is without odour, and is more soluble in saline than in pure water. Very dilute hydrogen chloride precipitates solutions of albumen, the precipi- tate being redissolved by an excess of the acid. This solution does not contain albumen, but a substance probably isomeric with it, which is, however, more easily obtained from muscular tissue : it is called syntonin. Among the products of the putrefaction of albumen, 230 ANIMAL CHEMISTRY. Nencki (18- 7 8-71) has obtained butyric and vale- rianic acids. Insoluble albumen heated with water in a sealed tube to 150° or 160°, dissolves, but this modification is not coagulated again by heat. Animal albumen containing 1.5 per cent, of soda may be regarded as a weak acid, and in presence of alkaline solutions it dissolves. A few drops of potassium hydrate are sufficient to form with albumen a gela- tinous compound, called potassium albuminate, which is soluble in water and no longer coagulable by heat. This liquid, diluted with water, is rendered turbid by acetic acid, but the precipitate is redissolved by an excess of acid. Albumen of the Serum. — This is easily soluble in con- centrated hydrochloric acid, and is not precipitated by ether. Injected into the veins it is absorbed. Egg Albumen. — This is more difficultly soluble in concentrated hydrochloric acid, and is precipitated by ether. Injected into the veins it is absorbed in very minute quantities, and can be found again in the urine. Albuminoid substances (fibrino-plastic substance, flbrinogene) are found in the blood; they have the general characteristics of albumen, but are distinguished from it by being precipitated with carbon dioxide. The soluble matter of the crystalline lens of the eye also possesses this property. The coagulation of albumen by alcohol, tannin, and heat, and the consequent formation of a sort of net- FIBRIN. 231 work which fills the whole liquid, and which precipi- tates all matters held in suspension, as well as certain substances in solution, explains the employment of white of egg for the clarifying of wine, syrups, also as a mordant, and the use of blood in sugar refining. FIBRIN. The blood of animals coagulates spontaneously shortly after leaving the body. This is due to the solidification of a substance called fibrin, which, on solidifying, forms a sort of net- work, imprisoning the globules of the blood, and gives rise to a gelatinous mass (clot). The researches made to explain this process of coagulation will be mentioned further on. Ether accelerates this coagulation. Sodium sulphate and glycerine retard or even arrest it. Pure fibrin may be obtained by beating fresh blood with twigs. It attaches itself to the twigs, and if then washed with water, and afterwards with alcohol, we obtain a dark- grey filamentous substance, which is insoluble fibrin. It may also be obtained by working clotted blood in water as long as it colours the water. Fibrin is insoluble in water, hot or cold, but if heated with it in close vessels it gradually loses its property of solidifying. It is soluble in alkaline solu- tions, and precipitable again by acids. Lehman has concluded from his analyses that fibrin is oxidized albumen, Smee affirms that if oxygen be passed into defibrinated serum, heated to about 232 ANIMAL CHEMISTRY. 36°, the albumen is gradually transformed into flocks of fibrin. This subject needs further investi- gation. Fibrin of blood swells when treated with water con- taining 1- 1000th part of hydrochloric acid. It is dissolved in stronger hydrochloric acid, and is then converted into syntonin. Freshly precipitated fibrin is dissolved at 35° to 40° in water containing certain salts, and notably in that containing potassium nitrate or sodium sulphate ; it decomposes hydrogen peroxide. The albumen in the egg is transformed into fibrin during incubation ; inversely, if fibrin be kept under water, it gradually becomes soluble, and this liquid, like albumen, is coagulated by the action of heat. Varieties of Fibrin. — The gluten which constitutes the plastic substance of cereals, has the composition and general properties of fibrin. When well-washed, muscular tissue is macerated with water containing ten parts in 100 of sea salt, it is partially dissolved; if this solution is poured into water a gelatinous mass is obtained on agitation. This substance washed on a filter has received the name of myosin, or musculin. It is soluble in acids, in dilute alkalies, and in a solution of sea salt ; this last solution coagulates at about 60°. Myosin, on dissolving in dilute acids, is changed into syntonin, which, like myosin, is soluble in acids and alkalies, but from which it is distinguished by its insolubility in salt water. Syntonin is more easily ob- tained by macerating flesh, which has been completely CASEIN. 233 deprived of blood by prolonged washing with water, containing 0.01 of hydrogen chloride. The macerated flesh is almost entirely dissolved. This solution is filtered and exactly neutralized with sodium carbo- nate ; the syntonin is precipitated in a grey, flocculent form. Blood fibrin contains about : C = 52.6 ; H = 7.0 ; N = 16.6; S = 1.2 to 1.6; = the difference, authors not agreeing very closely as to its exact com- position. CASEIN. Casein is the nitrogenous principle of milk. To extract it, milk is brought to boiling, and a few drops of acetic acid added. An abundant coagulum of casein mixed with butter (caseum) is formed. The pure casein is separated by washing this coagulum several times with water, alcohol, and ether. Casein is difficultly soluble in water, but is dissolved by alkalies. It forms with the alkalies soluble com- pounds, and with the other bases insoluble salts. Casein has the composition of the albuminates of soda, differing, however, from these by various re- actions, and by the amount of its levogyrate action on the polarized ray of light. Solutions of casein are not coagulated by heat, they simply become covered with a white film. They are precipitated by acetic and other organic acids ; milk curdles spontaneously, on account of the lactic acid formed in it. 234 ANIMAL CHEMISTRY. Many substances such as tannin, alcohol, plants with acid reactions and several others, the flowers of the artichoke, of the thistle, of the butterwort (Pinguicula vulgaris), and, above all, rennet from the stomach of a sucking calf, cause coagulation in milk. LEGUMIN, OR VEGETABLE CASEIN. Braconnot extracted, by means of water, from the seeds of leguminous plants (beans, peas) a substance called tegumin, and which has a close analogy to casein. VITELLIN. This substance is prepared by treating boiled yolk of egg with ether, which extracts the fatty matters. There remains a white substance insoluble in water. It can be obtained in a soluble state by mixing fresh yolk of egg with water. The clear liquid coagulates at about 70°, like albumen, of which it possesses the general properties. OSSEIN, GELATIN, CHONDRIN. The compounds of this second group are probably formed of a single substance, whose elements are differently aggregated, and also mixed with variable quantities of mineral substances. They are insoluble in water, alcohol, and acetic acid ; they swell in cold and dissolve in hot alkaline solutions. The organic substance of bones (ossein), treated with OSSEIN, GELATIN, CHONDRIN. 235 boiling water, furnishes gelatin. The cartilages, under the same circumstances, furnish a product which has most of the properties of gelatin, but which differs from it in being precipitated by acids and by alum ; it is called chondrin. To prepare gelatin, bones are treated with boiling water to remove the grease, then macerated with water acidulated with hydrochloric acid, which dissolves the mineral portions (calcium carbonate and phosphate). The organic portions remain undissolved, retaining the form of the bone, yet flexible and elastic. The solu- tion is poured off and employed in the manufacture of calcium hypophosphite, or of composts. The organic substance, well freed from acid by washing in milk of lime or a weak solution of sodium carbonate, is put into boilers with water, which is gradually raised to the boiling point. The organic matter gradually enters into solution. It is now decanted into a vat heated over a water bath, where various undissolved substances are deposited, and whence it is drawn into wooden moulds, where it solidifies. The gela- tin is removed from the moulds, cut into thin slices, dried on nets, and is now the glue of commerce. The tendons, skin, horns, and clippings of hides are also employed for the manufacture of glue; they are simply treated with boiling water. Darcet showed in 1817 that gelatin could be made directly from bones by digesting them with steam heated to 104°. The solution obtained has the appearance of soup, and it was hoped to thus pro- 236 ANIMAL CHEMISTRY. duce a very substantial nutriment quite cheaply ; but it has been found that the nutritive power of this substance is very small, and the use of " gelatine food " has been abandoned. The purest gelatin is the ichthyocol, or isinglass. It is made chiefly in Moldavia and on the borders of the Caspian Sea, from the swimming bladders of the sturgeon and of the acipenseres. Pure gelatin is solid, colourless, and transparent. Boiling water dissolves it in large quantities. The liquid solidifies to a jelly on cooling : one per cent, is sufficient to give water a gelatinous consistency. Continued boiling with water deprives it of the pro- perty of solidifying in the cold, or gelatinizing. Boiled with dilute sulphuric acid, it is transformed into glycocol. DIGESTION. 237 DIGESTION. An organized being cannot live without nourishment, that is, without obtaining from the bodies which surround it the materials necessary for the formation and the metamorphoses of its tissues. The food of animals is rarely assimilable in the state in which it is found in nature ; therefore it must undergo a preparation which shall render it absorb- able. Hence the existence of a particular function, digestion. This function is performed by the digestive organs. They vary in complexity with different animals ; they differ in form according to the nature of the food. In man the digestive apparatus is very complex. If the food is solid it must be dissolved. Every liquid, however, is not immediately assimilable ; it often also must be transformed in chemical and physical charac- ter. We shall now follow the food through the process of digestion, and explain the manner in which each class of aliments becomes soluble and absorbed. SALIVA. In the mouth the food is subjected to mechanical action under the influence of a liquid secreted by glands 238 SALIVA. situated in pairs on each side of the mouth (parotid, submaxillary, and sublingual). Tubes have been introduced into the ducts of the parotid and submaxillary glands, and by exciting secretion, the products of these glands have been separately examined. The salivas are not alike, and have different digestive properties, their combination, mingled with mucus, constituting " mixed saliva." The parotid secretion is a clear liquid, not viscous, and slightly alkaline, containing 1.0 to 1.6 per cent, of solid substances, among which are alkaline chlorides and phosphates; an organic substance soluble in alcohol and water ; another, ptyalin, which is the most important principle of the saliva ; and finally, potassium sulphocyanide. Ptyalin contains potassium, sodium, and calcium. It resembles compounds of albumen with these bases, is, however, gelatinous and not coagulable by heat or by most metallic salts. It is precipitated by mercury bichloride, lead acetate, and tannin. The submaxillary glands are dependent upon the chorda tympani nerve, and the branches of the great sympathetic nerve. The secretion varies as it is excited by the one or the other of these nerves. The liquid secreted after an excitement of the great sympathetic nerve is thick, alkaline, and rich in solid substances. The liquid obtained by the excitement of the chorda tympani is less concentrated. It is alkaline, and contains epithelial cells, small quantities of albumen, globulin, and a substance (mucin) to which SALIVA, 239 its mucilaginous appearance is due, and which is not found in the parotid secretion. The liquid of the sublingual glands has not as yet "been obtained pure ; concerning it we know only that it is a viscous solution. Buccal mucus has a slight acid reaction. Mixed saliva is a turbid, ropy, inodorous, tasteless liquid. It deposits debris of epithelium. In man its density varies from 1.007 to 1.008. It has an alkaline reaction, and contains from 0.7 to 1.0 per cent, of solid substances, of which about one-third is inorganic, chiefly alkaline carbonates, phosphates, and chlorides. It contains in solution more carbon dioxide than even venous blood. 1,000 parts of saliva contain : — Mitscherlich. Jacubowitsch. Water . . . 984.50 992.16 Solid substances . . 10.50 4.84 Ptyalin . . . 5.25 1.34 Mucus and epithelium 0.05 1.62 Sulphocyanogen . . ... 0.06 According to Longet, potassium sulphocyanide is a normal product of the saliva. It is recognized by placing in the saliva a ferric salt, which is coloured red. This salt does not exist in the blood, perspiration, lacrymal fluid, or pancreatic juice. Its amount is always very small, and its presence in saliva is doubted by Grautier. 240 ANIMAL CHEMISTRY. On boiling saliva it becomes opalescent, on account of the precipitation of albumen. Nitric acid colours it yellow by attacking the albuminoid substances. Alcohol precipitates from it ptyalin, mixed with nitrogenous compounds. Saliva exposed to the air becomes covered with a film of calcium carbonate, and concretions of this substance are often found in the salivary ducts and on the teeth. An adult can secrete about 1,200 to 1,500 grains of saliva in twenty-four hours ; the actual quantity varies with the dryness of the food. The saliva possesses evident mechanical functions in digestion. It facilitates mastication by impregnating the food ; it lubricates the bolus, and renders degluti- tion possible ; and finally, by virtue of its viscous and frothy consistency, it imprisons air, which passes into the oesophagus with the food. Deglutition is favoured much more by the mucus than by the saliva proper ; this mucus is secreted by glands found in the walls of the mouth and pharynx. It has been contested that the saliva has for a chemical function the saccharification of starch, as the food does not remain but for an instant in contact with it, and as the amount of saliva secreted is independent of the amount of starch in the food. The proportion of saliva increases when the food is dry or hard, and diminishes when it is soft, even when it is formed of boiled starch ; in short, it seems to vary inversely with the humidity of the food. SALIVA. 241 It lias been remarked that salivary glands exist in a rudimentary state in animals which, do not masticate their food. Mialhe indicates the following experiment : Chew some unleavened bread, then place it on Berzelius test paper. Eub another portion of the same bread with water, and filter the liquid. The first is not coloured by iodine, and * becomes brown on being boiled with potassa. The second turns blue with iodine. According to the same chemist this action is due to ptyalin, an amorphous substance insoluble in alcohol, of which 1 to 2 per cent, is present in the saliva, and which is able to saccharify as much as 2,000 times its own weight of starch ; it also effects this change with extreme rapidity. This substance has then the property of vegetable diastase-. It has also been shown directly by Messrs. Mialhe, Longet, and SchLf, that even if pure gastric juice itself does not have the property of saccharifying starch, this saccharification by the saliva is not arrested by the acidity of the gastric juice, and consequently the saliva which is carried into the stomach can continue to saccharify the starchy food in this organ. It is then very probable that the saliva performs this service in the process of digestion, though some claim that this ac- tion is only on food not yet thoroughly mixed with gas- tric juice. It appears to have no action on sugar, gum, cellulose, or albuminoid compounds. In inflammatory diseases of the mouth, as in the thrush, the saliva becomes acid, and weak alkaline 242 ANIMAL CHEMISTRYo beverages are prescribed. In Bright's disease urea is found in the saliva. Mercury is also present in cases of mercurial salivation. After the use of preparations containing iodine and bromine, these substances are found in this secretion. The tartar of the teeth contains, in 100 parts, 25 of organic substances, 75 of inorganic substances, formed chiefly of calcium phosphate ; the remainder is calcium carbonate, iron, and silica. GASTRIC JUICE. The gastric juice is secreted in the mucous mem- brane of the stomach by an immense number of glandular follicles, though not secreted when the stomach is empty. As soon as food enters the stomach, the mucous membrane swells, assumes a blood-red colour, and the gastric juice is at once secreted. The secretion can also be excited by irritating this membrane by ice, cold water, wine, gall, coffee, bismuth subnitrate, sodium bicarbonate, and alkaline substances in general. According to L. Corvisart, gastric juice secreted by mechanical irritation is most rich in digestive principles. We can easily procure gastric juice, or rather a mixed liquid, formed of this juice, stomachic mucus, and saliva, by making an aperture in the stomach of an animal, and it may be obtained free from saliva by previously ligating the oesophagus. GASTRIC JUICE. 243 The gastric juice may be freed, to a great extent, from the mucus by filtration. The mucus is alkaline. When the stomach has not received food for a long time, the mucous secre- tion alone is produced, and the liquid in the stomach may become alkaline. The gastric juice forms an almost colourless liquid, with a faint odour, decidedly acid reaction, and is somewhat denser than water. It may be preserved for a very long time without alteration, it loses its digestive properties on ebulli- tion, but is not altered by cold. Schmidt obtained the following analysis of gastric juice mixed with saliva : — Man. Dog. Organic matter 8.79 17.12 Hydrochloric acid 0.20 3.05 Potassium chloride 0.55 1.12 Sodium „ . 1.46 2.50 Calcium „ . 0.06 .62 Ammonium „ . .47 Calcium phosphate l ( 1.73 Magnesium „ . 0.14 0.23 Iron „ . 1 ( 0.08 Water . . 988.80 973.08 1000.00 1000.00 These analyses are the mean of several. It is, moreover, very evident that the composition of this liquid, as well as that of others in the body, must 244 ANIMAL CHEMISTRY. vary, not only in the quantity, but sometimes even in the nature of their constituents. All analyses of the gastric juice show that it is an acid substance. The nature of this acid has been the object of much discussion between different experimenters, and principally between Messrs. Blond- lot and Schmidt. According to the first, the acidity is due to acid calcium phosphate ; according to the second, to hydrochloric acid. It is true that calcium phosphate is found in the gastric juice, but according to Lehmann and Schiff, this salt is formed by the action of the gastric juice on the substance of the bones, and does not exist in the gastric juice of animals de- prived of this food. Consequently this substance is not a normal and constant constituent of gastric juice. Schmidt points to the following experiment. He determines the amount of chlorine in a known weight of gastric juice, by means of silver nitrate, and also determines the bases. Now, the quantity of hydro- chloric acid corresponding to the weight of chlorine determined by analysis, is always more than suffi- cient to neutralize the bases found; hence he con- cludes that hydrochloric acid exists in a free state in the gastric juice. Moreover, having determined the amount of free acid by saturating the gastric juice with a standard solution of a base, he found that the amount of free acid was about equal to the weight of the excess GASTRIC JUICE. 245 of hydrochloric acid resulting from the previous determination. Lactic acid is generally found in the gastric juice, and, according to Messrs. Bernard and Barreswill, this is probably the acidifying principle ; according to others, it exists there only when starchy food is used. Thus, recently, Eabuteau (9-80-61), by neutralizing gastric juice with quinia evaporating, treating with amy 1- alcohol, and obtaining the crystallized quinia, salt dissolved in the amyl-alcohol, found the free acid of the stomach to be hydrochloric acid; he was not able to discover lactic acid in the gastric juice. Butyric and acetic acids have also been detected in the gastric juice. When lactic acid is distilled with a dilute solution of a chloride, hydrochloric acid is found in the pro- duct : possibly the hydrochloric acid is produced in the stomach by the reaction of the lactic acid on the alkaline chlorides (?). It is difficult, according to Eiche, to admit that the hydrochloric acid is present in an absolutely free state, for calcium carbonate does not completely remove the acidity of the gastric juice ; and if this be submitted to distillation, the hydrochloric acid comes over only as one of the final products. The fact has also been directly established that the albuminoid substances unite with mineral acids, forming com- pounds possessing an acid reaction, and which have lost certain properties of free acids. B,. Maly (1 — 173, 227) has come to the conclusion, 246 ANIMAL CHEMISTRY. through experiments lately made as to the origin of the acid in gastric juice, that pure gastric juice con- tains no lactic acid, and that the origin of the hydro- chloric acid of the stomach is not due to the decom- position of the chlorides present by lactic acid. The source of the free hydrochloric acid of the stomach is, according to Maly, to be sought in a disasso- ciation of the chlorides, without the intervention of an acid. Charles Bichet, however (62 — '77), has been studying the properties of the human gastric juice upon the person of the patient on whom Yerneuil successfully performed gastrotomy. He has reached the following conclusions : 1. The acidity of the gastric juice, whether pure or mixed with food, is equivalent to 1*7 grammes of hydrochloric acid to a thousand grammes of fluid. 2. Acidity increases slightly at the end of digestion, and is independent of the quantity of liquid contained in the stomach. Wine and alcohol increase, but cane- sugar diminishes it. 3. If acid or alkaline matters are introduced, the gastric juice tends to return to its normal acidity. 4. The mean duration of digestion is from three to four and a half hours or more. Food does not pass successively, but in masses. 5. Accord- ing to four analyses made by a modification of Schmidt's method, it was proved that free hydrochloric acid exists in the gastric juice. 6. It is possible to extract all the lactic acid contained in the stomach, and to prove that there is one part lactic acid to nine parts hydrochloric acid. 7. Following the method of Berthe- GASTRIC JUICE. 247 lot, that is, by agitation with anhydrous ether and deprived of alcohol, it can he shown that lactic acid is free in the gastric juice. 8. The question so long in controversy as to the nature of the free acid in the stomach seems, according to Pichet, almost solved, and it may be said that in every 1,000 grammes of gastric juice there are 1*53 grammes of hydrochloric acid and 0*43 of lactic acid. Pepsin. — Observation has shown that if an infusion of the mucous membrane of the stomach be made, and the liquid acidified, it dissolves albuminoid substances as well as the gastric juice. The mucous membranes of the other organs do not possess this property. Wasman was the first to extract from the mucous membrane of the- stomach the active agent of this transformation. It is an albuminoid substance known by the names of pepsin, chymosin, and gasterase pepsin. The best method of preparing pepsin is that of Schmidt. Gastric juice is neutralized with lime-water, filtered, evaporated to the consistency of syrup, and precipitated with concentrated alcohol. The pepsin is re-dissolved in water, precipitated with lead acetate ; the precipitate is collected and decomposed by a current of hydrogen sulphide. The sulphur is separated by filtering, and the liquid containing pepsin is evaporated to dryness at a low temperature. The method by Bruecke we omit, as it appears to give a less pure product. Pepsin is a yellowish gummy substance, soluble in water. Dissolved in 50,000 — 60,000 parts of acidu- 248 ANIMAL CHEMISTRY. lated water, it dissolves coagulated white of egg in six or eight hours. Alone it does not possess this dis- solving power. Heat does not coagulate pepsin, but destroys its digestive properties. The union of pepsin and an acid is necessary for diges- tion. The acids of the stomach have been replaced by most of the other acids, with success. Artificial diges- tion may be very easily produced with pepsin and an appropriate amount of acid, or better, with gastric juice itself. If the proportion of acid is too large the action is stopped. The most suitable temperature is 38° to 40° ; the action is very slow at 50° and at 12° ; no action takes place at 100° or at 5°. Liquid albumen does not coagulate in the stomach, it is dissolved, and the solution is not coagulable by heat or acids. Coagulated albumen is converted into a soft, nacreous substance, then into a sort of pulp, which is gradually dissolved. According to some chemists, albumen is absorbed directly. Fibrin is more energetically attacked by this secre- tion than ordinary albumen, which seems to prove that fibrin is neutral, while the alkali of the albumen, by saturating the acidity of the gastric juice, retards its action. Fibrin of the blood is attacked more rapidly than that of the muscles. At first it swells, then changes into a grey powder, which is finally dissolved. Grluten is dissolved very readily. Liquid casein co- agulates, and afterwards dissolves in the same manner as coagulated albumen. GASTRIC JUICE. 249 The name peptones is given to the products of the transformation of albuminoid substances by the action of gastric juice. J. Murk has lately observed the pre- sence in saliva of a peptone ferment (60-'7 6-1800). Peptones are soluble in water, coagulated by alcohol, lead acetate, mercury bichloride, and tannin. They differ from albumen, inasmuch as their solutions are not coagulable by heat; peptones obtained from osseous and gelatinous tissues are not precipitated by potassium ferrocyanide. According to Meissner, the gastric juice produces with albumen, at first, a substance, parapeptone, identical with syntonin, which afterwards forms various other peptones. Peptone (a) is precipitated by nitric acid, also by potassium ferrocyanide, acidified with acetic acid. Peptone (b) is precipitated by the latter of these reagents. Peptone (c) is precipitated by neither reagent. Hoppe-Seyler and Grautier doubt the existence of these peptones. The gastric juice does not dissolve all the nitrogenous substances of the food. A portion escapes its action, and is subsequently transformed in the intestines. It is generally admitted that gastric juice has no action on fatty substances. Starch is not affected by the gastric juice, but it seems to be substantiated that the saliva continues its action on these substances in presence of the gastric juice. (Bruecke, Gautier, Besanez. Ed. of 1878, p. 831.) 250 ANIMAL CHEMISTRY. In catarrh of the stomach the mucous secretion is very abundant, and various organic acids are formed. LIVER. BILE. Besides bile there have been extracted from the liver glucose, a substance analogous to starch, called glycogene, fatty substances, and various nitrogenous products, viz., leucin, tyrosin, and xanthanin. The quantity of bile secreted is quite large, Gruinea- pigs secrete in twenty-four hours a quantity of bile amounting often to several times the weight of their liver. In order to extract it from these or other animals the gall bladder is emptied, or the biliary ducts are ligatured, and an opening made in them. The bile before entering the gall-bladder is odourless. On remaining in this vesicle it acquires a strong odour, a bitter taste, becomes concentrated, and forms a viscous greenish or brown liquid. Its density varies from 1.025 to 1.033. Its normal reaction is slightly alkaline. It is co- agulated by acids ; the coagulum is formed of two acids, taurocholic and cholic, or glycocholic acids. Human bile contains from 9 to 18 per cent, of solid substances ; a less quantity is found in the bile of the ox and pig. More than half of this residue is formed of combinations of the acids just named, with different bases, though mainly with soda. The bile may therefore be regarded as essentially a saponaceous compound. The other solid constituents COMPOSITION OF BILE. 251 of the bile are — a neutral organic substance called cholesterin, a colouring matter, neutral fatty substances and salts ; urea is sometimes found in it. Strecker has extracted a base from bile which he calls cholin. This substance is identical with neurin, which has been extracted from the brain and yolk of egg. Its formula is C 5 H 15 N0 2 . COMPOSITION OF BILE. (Gorup-Besanez.) Water Fatty substances Salts of the biliary acids Fat . Cholesterin Mucus, colouring- matters Mineral salts Man of 49 years, de- capitated. 822.7 177.3 107.9 47.3 22 1 10.8 Woman of Man of 68 Child ° f • *f •29 years, de- years, killed, 5 ^ 7 /' G1< capitated. 898.1 lul.9 56.5 30.9 14.5 6.3 by a fall. 908.7 91.3 73.7 17.6 of an injury. 828.1 171.9 148.0 23.9 ae ash of ox gall contains ; — Sodium chloride o • 27.70 Sodium phosphate , o • 16.00 Potassium „ e o 7.50 Calcium „ o • 3.02 Magnesium „ CI • 1.52 Ferric oxide o • 1.52 Silica . 3 8 0.36 Small quantities of nitrogen have also been found, 252 ANIMAL CHEMISTRY. and considerable proportions of carbon dioxide ; this last gas may be extracted by a mercury pump. Animal food augments the quantity of carbon dioxide. Acids of the Bile. — Human bile contains much more taurocholic than glycocholic acid. The former alone exists in the bile of the dog ; it abounds in the bile of serpents and fishes. Grlycocholic acid is wanting in carnivorous animals. Both exist abundantly in the bile of the ox. The bile of the pig contains special acids : hyoglyco- cholic acid, and taurohyocholalic acid. In order to obtain the two acids of the bile, neutral lead acetate is added to ox-gall, which precipitates the glycocholic acid as a lead salt. This compound is col- lected, washed, boiled with 85 per cent, alcohol, and the boiling liquid filtered. It is then exposed to a current of hydrogen sulphide while yet warm ; the lead sul- phide is thrown on a filter and washed until the liquid becomes turbid. The glycocholic acid precipitates out of the solution, and is purified with boiling water. The alkaline taurocholate is not precipitated by the lead acetate. To the first liquor lead subacetate is added until the precipitate takes on a fatty consistency ; this precipitate is collected, washed, and suspended in water. A current of hydrogen sulphide is passed through the water, the liquid filtered and evaporated. The taurocholic acid is deposited as a white powder. Gtlycooholic Acid, C 2g H 43 N0 6 , forms white needles moderately soluble in alcohol. One part is soluble in TAUROCHOLIC ACID. 253 100 parts of boiling and 300 parts of cold water. "With alkalies and barium it forms soluble crystalline salts. Boiling alkaline solutions and dilute acids, separate it into cholalic acid and glycoeol by combining with water. C 26 H 43 N0 6 + H 2 = C 24 H 40 O 5 + C 2 H 6 N0 2 Glycocholic acid. Water. Cholalic acid. Glycocol. On being boiled with concentrated hydrochloric acid or sulphuric acid, it furnishes the following products : Cholonic acid . . C 26 H 41 N0 5 Cholo'idic . • C 24 H 38 4 Dyslisin 2 4-ri 36 (J3 Taurocholic Acid, C 26 H 45 N0 7 S, has not yet been obtained crystalline. It dissolves in alcohol and water, imparting to these an acid reaction. It is partly destroyed by the evaporation of its aqueous solution. It combines with one molecule of water on being boiled with alkaline solutions, cholalic acid and taurin being formed. C 26 H 45 N0 7 S + H 2 = C 24 H 40 O 5 + C 2 H 7 N0 3 S Taurocholic acid. Cholalic acid. Taurin. The Bile Ferment. — "W. Epstein and J. Miiller 254 ANIMAL CHEMISTRY. (60-1875-679) have lately investigated the influence of different substances upon the action of the ferment of the liver. Dilute aqueous solutions of carbolic acid (1 : 300) do not prevent the transformation of the glycogen into sugar if brought into contact with fresh, finely-chopped liver; yet this carbolic acid solution protects the liver from putrefaction for a long time. Five per cent, solutions of sodium chloride and sodium sulphate do not prevent or influence the transformation of the glycogen of the liver. Alkalies render the change slower, acids prevent it entirely ; even when very dilute they greatly retard it. The action of acids, however, is only tran- sitory ; on neutralizing them the action of the ferment at once begins. Whether carbon dioxide prevents fermentation or not, has not been ascertained with certainty. The supposition of Tiegel that the change of the glycogen of the liver into sugar is connected with the destruction of the blood -corpuscles was not confirmed by the experiments of Epstein and Mtiller. They prepared from liver — moistening it with carbolic acid, drying at 30°, extracting with glycerine, and precipitating with alcohol — a ferment peculiar to liver, which converts glycogen into sugar very rapidly and easily. Taurin, C 2 H 7 N0 3 S. — This substance may be pre- pared by boiling ox-gall with an excess of hydrochloric acid for several hours. Filter and add to the liquid five or six times its weight of boiling alcohol, and allow to cool slowly. The taurin, which is almost CHOLESTERIN. 255 insoluble in alcohol, will separate out in colourless rhoniboidal prisms. Taurin has been produced artificially by Strecker, on heating isethionate of ammonia at 200°. This salt loses one molecule of water, and taurin remains. (C 2 H 4 ,S0 2 )" |-0 2 = H 2 + [(C 2 H 4 , S0 2 )", HO]' 1 Hj 1N This substance is, therefore, an amide like glycocol. Taurin is found in the muscles of certain mollusks. Cholesterin. — C 26 H 44 0,H 2 0. — This substance is widely diffused in the animal organism. Biliary cal- culi are almost entirely formed of it ; it is found in the blood, yolk of eggs, spleen, mis, in various tumours, in the nerves and brain. It is easily extracted from biliary calculi, which are pulverized, suspended in alco- liol with animal charcoal, and the mixture brought to boiling ; after some time, the liquid is filtered. The cholesterin deposits on cooling. Berth elot has shown that cholesterin has been wrongly classed among the neutral fatty substances ; it is not saponifiable. He considers it a monatomic alcohol. C 26 H 43 ) n Hj u * He has prepared the ethers of cholesterin by the action of acids : — 256 ANIMAL CHEMISTRY. Acetic ether q 2 |^ q! 0. This alcohol is dehydrated by anhydrous phosphoric acid, producing the carbo-hydride : — C 26 H 42 cholesterilene. Cholesterilene is colourless, odourless, and tasteless, crystallizable in brilliant rhomboidal tablets, fusible at 145°, and volatile at 360°. Water does not dissolve it ; it is slightly soluble in cold alcohol, and quite soluble in boiling alcohol and ether. It is soluble in the taurochlorates. It turns the plane of polarization to the left. Heated with a few drops of nitric acid it becomes yellow, and this yellow substance, on being touched with a drop of ammonium hydrate, turns red. Sul- phuric acid colours cholesterin red ; if chloroform is added, a blood-red colour is obtained which, before disappearing, becomes successively violet, blue, and green. According to Flint, cholesterin is an excrementitious substance, which results from the disintegration of nervous tissue, as it is not found in the blood entering the brain, but is found in the blood of the veins which leave it. Also, though absent in muscular tissue, it is always found in the nerves. It is absorbed by the blood and eliminated by the liver, as it is abundant in the blood of the hepatic artery and the vena porta, COLOURING MATTERS OF THE BILE. 257 while little or none is found in the blood of the sub- hepatic veins. During digestion it is changed into a substance called stercorin, and evacuated in this state ; also, when cholesterin is not discharged into the in- testines, a decrease in the production of stercorin is observed. The retention of cholesterin in the blood gives rise to the serious malady cholesteremia. Colouring Matters of the Bile. — The bile fur- nishes two colouring matters : one brown, called bilirubin, cholepyrrhin, or bilifalvin ; the other green, called biliverdin. Bilirubin, C 16 H 18 N 2 3 . — This substance may be pre- pared by agitating fresh bile with water, ether, and dilute hydrochloric acid, which do not dissolve it, then with chloroform ; the bilirubin dissolves, and is de- posited on evaporation in orange-red crystals. This body is dissolved by alkalies. It forms with lime a sort of lake, sometimes also found in the body (biliary pigment). This substance has been found not only in the liver, but also in the brain, in cases of haemorrhage, and in the placenta of dogs. Biliverdin, C 16 H 20 N 2 O 5 , appears to be a product of alteration of bilirubin. It is first formed in the putre- faction of bile, is then changed spontaneously into biliprasin, C 16 H 22 N 2 6 (?). Biliverdin may be prepared by allowing an alkaline solution to stand for a time in the open air ; this solu- tion is then precipitated with hydrochloric acid. Both colouring matters are precipitated in this manner, and 258 ANIMAL CHEMISTRY. the biliverdin may be removed by treating the precipi- tate with alcohol, which dissolves this substance alone. Stoedler announces that he has extracted from bile two other colouring matters — bilifuscin and bilihumin. The former has been recently studied by Simony (111-73-181). Action of the Bile on Food. — The bile is not simply extracted from the blood by the liver, but is elaborated by it ; the biliary acids are not found in any other part of the body, and the blood, in passing through the liver, loses its fibrin and a portion of its albumen. It has also been proved that the bile is formed in the liver, by removing this organ from frogs ; when, after this operation, biliary acids were no longer found. Lehmann believes that the fibrin, wholly or in part, taken up by the liver, is transformed into glycogen. The bile neutralizes the gastric juice, yet this satu- ration is not complete ; the acids of the bile thus liberated have perhaps a certain utility in the intestines. The bile has no digestive action on amylaceous matters, but assists in the digestion of fatty substances. Messrs. Schmidt and Bidder have shown that dogs assimilate, per kilogramme and per hour, under ordi- nary conditions, 0.465 gramme of fat, while only 0.093 gramme is absorbed when the bile has been removed through a fistula. The chyle of a dog fed with fat contains at least 3 per cent, of this matter ; if the action of the bile be prevented by a fistula, this quan- tity will fall below 1 per cent. On agitating bile with oil, it forms a rapid and ACTION OF THE BILE ON FOOD. 259 persistent emulsion. Oils rise higher in a capillary tube when moistened with bile than when moistened with water. Bile has no action on albuminoid substances in their ordinary condition. It precipitates acid solutions of albuminoid matter, but an excess of bile re-dissolves these precipitates. It is therefore not impossible that the bile takes part in the digestion of the albuminoid substances, acidified but not absorbed in the stomach. Bile is found throughout the smaller intestines ; it attaches itself to their folds, and by its adhesive charac- ter retains the non-absorbed food, and facilitates the action of the intestinal fluids. Bile is not found in the large intestine, although we find there cholalic acid, taurin, and dislysin ; glycocol has not been found. The excrements contain also taurin, dislysin, and cholalic acid, but Hoppe-Seyler, by determining the amount of this latter acid in the excrements, has shown that the greater part disappears in the intestine. The bile appears to prevent putrefaction of the con- tents of the intestine. The bile, therefore, after what we have stated, would seem to be a secretion, and also an excretion. But little is known in regard to the formation of the immediate principles of the bile. We owe to Lehman an ingenious and probable hypothesis regarding the formation of the acids of the bile. According to his theory the fatty substances, espe- cially olein, play an important part in their produc- 260 ANIMAL CHEMISTRY. tion. In fact, the cholalic acid, like oleic acid in contact with alkalies, is broken up into an acetate and palmitate. Also the blood in passing through the liver loses fat ; the amount of bile increases when the food is rich in fatty and nitrogenous substances, and the amount of fat increases as the bile diminishes and diminishes as the bile increases. The bases to which these acids are united are derived from the blood, for it has been proved that the blood contains less salts on leaving the liver than on entering it. The nitrogen of these acids, in the taurin and glycocol, is obtained from the albuminoid matters, as the blood, in passing through the liver, leaves behind a notable quantity of these substances. The sulphur of these products has the same origin. Bilirubin appears to have great analogy with hsematoidin, which results from the alteration of the colouring matter of the blood ; hence it would seem rational to admit that the colouring matter of the bile is derived from that of the blood, and that the haemo- globin is destroyed in the liver. This explains why no blood is found in the bile. The biliary secretion augments two or three hours after eating, and increases up to the thirteenth or fourteenth hour. Vegetable food produces bile in less quantity and less concentrated than animal food. Fatty aliments, mixed with nitrogenous substances, increase both the amount of the bile and its richness in solids. PANCREATIC JUICE. 261 The injection of calomel increases the secretion of bile. The biliary substances diminish in diabetes, in tuberculous affections, in dropsy, and typhus ; increase in choleric persons, and in diseases of the heart and abdomen. The biliary secretion diminishes in fevers. Biliary Calculi. — These are divided into biliary or cystic, hepatic, and hepato- cystic calculi, according to their origin. They are composed of cholesterin, mixed with the colouring matters of bile and mucus. Cholesterin forms 80 per cent, of these calculi. To extract the cholesterin the powdered calculus is treated with boiling alcohol ; on cooling, beautiful nacreous blades of cholesterin separate out. Ox bile (gall) is employed for removing grease. It may be prevented from putrefying by evaporating to the consistency of syrup. We shall speak of glycogen under the head of nutrition. PANCREATIC JUICE. The pancreatic juice is a liquid, colourless and some- what viscous, having a saline taste. Its density is not uniform, as it contains variable proportions of solid matter, which have been found to amount to as high as 11 per cent. Its reaction is alkaline, and due to sodium hydrate. The most important proximate principle of this juice is 262 ANIMAL CHEMISTRY. an albuminoid substance called pancreatin. In it is likewise found a fatty substance, also leucin, tyrosin, xanthin, and several salts, among which are sulphates and chlorides. This juice owes to the pancreatin present its property of coagulating with heat, alcohol, and acids. This fact led to the belief, formerly, that the albuminoid principle of this juice was albumen ; this is not true, however, as the coagulum formed by alcohol re-dissolves in water and re-assumes the viscous appearance and the charac- teristics of pancreatic juice. Pancreatin is prepared by pouring 85 per cent, al- cohol into pancreatic juice. White flakes are formed, which are soluble in water, yielding a solution which possesses, to a high degree, the property of converting starch into sugar. Jenneret states (18-77-389) that the action does not require oxygen. Pancreatic concretions contain variable proportions of nitrogenous organic matter and calcium carbonate and phosphate. Action of Pancreatic Juice. — This juice appears to act upon the three classes of organic aliments ; it promptly forms an emulsion with neutral, fatty sub- stances, and is even capable of saponifying them. Its action is most rapid at about 35° ; its action is arrested by acids, even the acidity of the gastric juice retarding its action. It has been found, also, that in chyle neutral fatty substances predominate over acid fats, and it is therefore believed that the pancreatic juice renders fats assimilable by forming an emulsion witk ACTION OF PANCREATIC JUICE. 263 them. The bile and intestinal secretion share with the pancreatic juice this property, for it has been shown that the chyle contains emulsions of fat, after the ligature of the pancreatic duct : their action, however, is very weak, as Bernard found that if the pancreatic juice be prevented from entering the intestines, the greater part of the fatty substances are found unchanged in the excrements. Corvisart, Kuhne, and others have shown that this juice dissolves fibrin and coagulates albumen, trans- forming them into assimilable products, analogous to the peptones. It, however, will act alone, whatever may be the state of the liquid, while pepsine requires the co-operation of an acid. According to Schiff the functions of the spleen are connected with those of the pancreas, as the pancreatic juice has no action on albu- minoid substances after the spleen has been removed. Moreover, and this, according to Bouchard at and Sandras, is its principal role, the pancreatic juice is the chief agent in effecting the transformation of farinaceous food. The transformation of starch into glucose is slow, as farinaceous mattex has been found in the intestines twenty-four hours after eating. It is probable that only a small quantity of the starch is absorbed in the form of glucose, the greater part being normally absorbed in the form of dextrine. The transformation continues, absorption having been accomplished, under the action of the ferment absorbed at the same time, with the dextrine. 264 ANIMAL CHEMISTRY. Pancreatic juice is rapidly decomposed in contact with the air. Claude Bernard states that an infusion of pancreas, or a solution of pancreatic juice, after having stood in the air for some time, assumes an intense red colour on the addition of chlorine water. Nencki (18-'78-79) is of the opinion that pancreatic digestion is essentially a process of putrefaction. INTESTINAL FLUIDS. These liquids are complex products even when the ducts conducting the bile and pancreatic juice to the intestines are closed, as there are several varieties of glandular apparatus which secrete liquids throughout the length of the intestinal canal. Colin has shown that mucus is also secreted. This physiologist, by binding the intestine at two points, about two metres apart, was enabled to obtain about one hundred grammes of the liquid secreted by the glands of Lieberkuhn, and having removed the mucus by deposition and filtration, he examined its properties. It is a limpid liquid, slightly yellowish, secretion, whose density is 1.010 and reaction very alkaline. Saturated with an acid it is coagulated by heat. It is also coagulated by alcohol and precipitated by lead acetate. This fluid continues the transformation of farinaceous substances into dextrine and sugar, and forms emulsions INTESTINAL FLUIDS. 265 with fatty matters. Although possessing an alkaline reaction, it acts upon albuminoid substances. Thus, according to Bidder and Schmidt, flesh and albumen coagulated by heat, and enclosed in the intestines by ligature, soften, dissolve, and are digested ; consequently, the intestinal fluid completes the digestion of nitro- genous substances : it is not known what constitutes its active principle. Thiry found in pure intestinal fluid from a dog : Water • . 97.585 Albuminates .... 0.802 Other organic substances 0.734 Inorganic substances 0.879 The gases of the smaller intestines are chiefly carbon dioxide and hydrogen. In the larger intestine these gases are mingled with methane, and traces of hydrogen sulphide ; the methane amounts to as high as 50 per cent, of this volume when the food is vegetableo The excrements contain 10 to 15 per cent, of solid substance, of which 6 to 7 per cent, are mineral. In them has been found stercorin or serolin, which is a fatty non-saponifiable matter, a product of the decomposition of cholesterin, also a white crystalline substance, called excretin, which contains sulphur, and which probably effects the elimination of this element from the system. Calcareous and magnesian phosphates, sodium 266 ANIMAL CHEMISTRY. chloride, a small quantity of silica, fatty matter, pro- ducts of the decomposition of the acids of the bile, of the epithelium, and the tissues of the vegetables are also found. The use of iron preparations colours the excrements blackish- green (iron sulphide). Calomel gives them a light green colour. If they contain blood the colour will be dark or nearly black. Cholera excrements contain coagulated albumen, cystoid corpuscles, and chlorides ; common salt amount- ing sometimes to over one-half the total weight. In dysentery and in Bright's disease mucus is found. In certain excrements the presence of alloxan, a pro- duct of the oxidation of urea, has been detected. In typhoid fever they are mostly fluid and alkaline. On standing a viscous mass deposits, containing mucus, food debris, and generally crystals of magnesio-ammonium phosphate. The fluid above the deposit contains albumen, various soluble salts and biliary constituents. Addition of nitric acid produces a rose-red coloration, as is also the case in cholera stools. Subjoined are the results of two analyses of human excrements, which from the inherent difficulties of such investigations cannot be regarded as exhibiting their composition with very complete accuracy. The one by Wehsarg is of recent date : — SUMMARY OF DIGESTION. 267 3erzelius Water • • 75.30 Biliary salts . . 0.90 Mucus and biliary resins 14.00 Albumen . 0.90 Extractive matters . 5.70 Aqueous extract 5.340 Alcoholic „ 4.165 Etherous „ 3.070 Food debris . 7.00 8.300 Mineral salts . . 1.20 Earthy phosphates . 1.095 Total salts 29.70 Wehsarg. 73.300 21.970 Intestinal Concretions. — These contain a large proportion of fatty matter, a substance analogous with fibrin, calcium phosphate, and sodium chloride. The name bezoar is given to the intestinal concretions found in gazelles and goats. They are formed some- times of an organic (lithiofellic) acid, sometimes of calcium and ammonio-magnesium phosphates. SUMMARY OF DIGESTION. To recapitulate, the food is mechanically divided in the mouth by the action of the tongue, teeth, and the saliva, which latter commences the transformation of the starchy matter. The bolus formed passes through the oesophagus, and arrives in the stomach, where the 268 ANIMAL CHEMISTRY. digestion of the greater part of the nitrogenous sub- stances is effected by the action of the gastric juice. The majority of these substances having become assimilable, are absorbed by the walls of the stomach, and the remainder of the food passes into the duodenum. There the emulsion of the fatty matter is prepared, and the transformation of the starch into glucose effected by the action of the bile, pancreatic juice, etc. This latter ffuid also effects the digestion of the nitrogenous matters. The food as modified by these different changes forms chyme. It now enters the jejunum, and moves forward by peristaltic and muscular motions. It here receives the secretions, which complete the transforma- tion of starch into sugar, the solution of the albuminoid matter, and the emulsion of the fats. The chyliferous vessels absorb almost exclusively these latter substances, while the intestinal veins absorb the products of the transformation of the fluids and albuminoid bodies. The absorption of the liquid products of digestion, and, in general, the absorption of liquids, is effected by means of a very complex mechanism. Diffusion takes the principal part in this process ; in fact the animal membranes are lined with colloid cells, through which diffusion takes place with great rapidity, and we have seen that, although albuminoid substances are but slightly dialyzable in a natural state, they become quite readily so on being transformed into peptones. ABSORPTION. 269 ABSORPTION. CHYLE, LYMPH. A very considerable quantity of lymph and chyle is constantly poured into the blood. These fluids are very analogous in character ; they have a circulatory movement; they are formed of a liquid (serum) in which float globules capable of uniting to form a clot or coagulum ; their composition is also similar, there being, in fact, little difference, except in the proportion of their elements. The chyle is a lactescent fluid contained in special lymphatic vessels, into which it passes directly from the intestines ; it accumulates in the mesenteric glands, whence it passes into the thoracic duct. It may be ob- tained by opening this duct and ligating the same near where it enters the sub-clavian vein. However, at this point it has already undergone elaboration, and is mingled with lymph coming from different points in the body. Before describing the chyle, it should be remarked that the knowledge we possess of this fluid is based chiefly upon investigations among the lower animals. 270 ANIMAL CHEMISTRY. The chyle of an animal deprived of food is yel- lowish ; during digestion, especially of fatty food, it is lactescent. This appearance is due to the fatty bodies present, for if it be agitated with ether it loses its milky appearance. It has a feeble odour, a slight taste, and its reaction is faintly alkaline. Chyle contains fibrin, albumen, and urea. The pre- sence of casein" is suspected, but not certain ; yet the albumen of the chyle is more alkaline than ordinary albumen. The serum of chyle becomes covered with a film during evaporation ; it coagulates only in small flakes, and acetic acid precipitates it but partially. Chyle separated from the body coagulates in ten to fifteen minutes, producing a clot floating in an albu- minous liquid ; this coagulation is due to the fibrin present. Lymph is a colourless, or nearly colourless, liquid. It reaction is alkaline, which appears due, like the alkalinity of chyle, to a matter analogous with casein. It contains white globules, fibrin, albumen, urea, fatty bodies, and salts, which are chiefly lactates. It coagulates after being exposed to the air for a few minutes, producing a thin, soft clot, coloured red by globules of blood. Hobin found the composition of human lymph and chyle to be, in 1000 parts, as follows : — LYMPH, CHYLE. ^71 Lymph.. Chyle. "Water 960 to 965 900 to 990 Sodium chloride 4 „ 6 5 „ 7 ^ Sodium carbonate 1 „ 2 not determined Calcium carbonate Alkaline and calcare- ^0.05 „ 2 0.80 to 3 ous phosphates Alkaline sulphates . 0.23 „ 0.50 not determined Crystallized organic } principles (urea, r 3 „ 8 5 to 9 glucose) . . ) Fatty bodies . 2 „ 9 10 „ 36 Albumen . 33 „ 60 30 „ 40 Fibrin 1 „ 5 3 „ 4 Peptone . 3 „ 4.5 6 „ 8 Hematosin 0-6 0.6 Wurtz has found urea in the lymph of various animals. The above analyses do not wholly agree with those of other chemists, and from the variable character of these two fluids, and the inherent difficulty of their analysis, the foregoing figures must be considered as giving only an approximative idea of their chemical composition. The variations in composition are greater, however, in chyle than in lymph. 272 ANIMAL CHEMISTRY. EESPIEATION. THE BLOOD. The blood is at once the nutritive and the purifying fluid of the body. From one part of the body it gathers the liquids elaborated by digestion, and in another it takes from the air its vital principle, oxygen, to act upon these liquids ; also it collects in different parts of the body the various effete products, and carries them to the organs destined to eliminate them. The blood also serves to distribute heat throughout the body. It circulates incessantly in the capillaries, arteries, and veins. Arterial blood is vermilion red; venous blood is reddish brown. Its odour varies somewhat with the species, and seems more marked in the male than in the female. According to Barruel, sulphuric acid increases its odour. Its taste is slightly saline. Its density varies be- tween 1.045 and 1.075. It has an alkaline reaction, which is due to sodium compounds. On placing under the microscope a very thin mem- THE BLOOD. 273 brane like the foot of a frog, it may be seen that the blood has a rapid circulatory movement, and that it is formed of a colourless liquid (plasma), in which floats an immense number of globules, drawn with it in the circulating current. The globules are microscopic in size, the majority are red, yet there are some which are colourless. A great many analyses of blood have been made. The results vary according to the physiological con- ditions of the subject, but the following tables give an average result: — Venous BloocL Man. Woman. "Water . • 780.00 791.00 Grlobules 140.00 127.00 Albumen 69.00 70.00 Fibrin . 2.20 2.20 Extractive matter salts . and ) 6.80 7.40 Serolin . 0.02 0.02 Fatty matters containing ) phosphorus . . jj 0.49 0.46 Cholesterin . 0.09 0.07 Salts of fatty acids 1.00 1.05 Loss .40 .80 1000.00 1000.00 274 ANIMAL CHEMISTRY. Salts contained in 1000 grammes of blood :- Sodium chloride . 3.10 3.90 Other soluble salts . 2.50 2.90 Iron o . 0.565 0.541 Phosphates . 0.330 354 (Becquerel and Rodier.) The blood on leaving the body loses its fluidity in a few minutes, becomes viscous, and changes into a gelatinous mass which gradually contracts and forces out drops of liquid, serum, which unite around the coagwlum or clot. This clot gains in consistency, and after ten to thirty hours it ceases to contract. Composition,, Serum . 870 Clot ...... 130 1000 Each of the 'two parts composing the blood has the following composition : — THE BLOOD. 275 Clot i Fibrin . i Griobules. /Water . Albumen Oxygen . Nitrogen Carbon dioxide Extractive matter . Phosphorated fat . Cholesterin Serolin . Margaric acid. Sodium chloride Potassium chloride . Serum ( Ammonium chloride Sodium carbonate . Calcium carbonate . Magnesium carbonate Calcium phosphate . Sodium phosphate . Magnesium phosphate Potassium phosphate Sodium lactate Salts of fixed fatty acids Salts of volatile fatty acids Yellow colouring matter. ia?l 180 790 70 > 10 1000 (Dumas). 276 ANIMAL CHEMISTRY. Many other substances also exist in the blood. We may say, in a general way, that it contains most of the immediate principles which compose the tissues and liquids of the body. Coagulation of the Blood — Serum. — The blood, we have said, coagulates on being removed from the body. This coagulation seems to be due to the fibrin, for if the blood be beaten with twigs, the fibrin is seen to attach itself to the branches, and the blood has lost its property of coagulating. The serum of the coagulum is not therefore identical with the plasma. This latter contains fibrin, and the former has been freed of it. The fibrin imprisons the globules of the blood, and these together form the coagulum. Coagulation is net due to the fact that the blood remains at rest on leaving the body of the animal, or because it becomes cooled, for by keeping the blood in motion and maintaining the temperature of the body, solidification is not arrested. It is not due to the presence of air, as coagulation takes place in other gases and in a vacuum. Acids coagulate blood. The rapidity of coagulation varies from a few minutes to several hours. It is slower in the blood of the vigorous than in that of weak persons. It is accelerated by raising the temperature from 30° to 48°. It is retarded several hours by lowering the tempera- ture to 0°. The addition of albumen, sugar, and solution of alkaline salts produces the same effect, and coagulation is even arrested by concentrated solutions of certain salts, especially sodium sulphate. If pulverized sodium chloride be added to this liquid COAGULATION OF THE BLOOD — SERUM. 277 it furnislies flakes of an albuminoid substance, which, according to Dennis, is different from albumen and fibrin. He has given it the name ofplasmin. It is very soluble in water, and is easily decomposed into soluble and insoluble fibrin, which, according to this chemist, is the cause of coagulation. Yirchow and Schmidt regard fibrin as produced by the combination of two albuminoid principles of the blood, the fib rino-plastic substance or paraglobullne and fibrinogen or metaglobuline, at the moment when the blood is removed from the body. These two bodies may be obtained by passing a current of carbon dioxide through plasma, diluted with ten times its volume of water at 0°. The fibrino- plastic substance is immediately precipitated in white flakes, which are collected on a filter and washed with water, charged with carbon dioxide, as aerated water dissolves it. The stream of carbon dioxide is now allowed to pass through the liquor for a long time. At first an abundant foam is formed, then the fibrogene separates out as a glutinous mass. If these two substances are separately dissolved in water which is slightly alkaline, and are then mixed, a gelatinous matter separates out which soon forms into filaments, analogous in appearance to fibrin. According to Schmidt these two substances require for their action the presence of a ferment, which is not developed in blood during circulation, but which is produced as soon as the blood is removed from the body; this ferment has not been isolated — whence is it derived ? 278 ANIMAL CHEMISTRY. According to others, the fibrin is already formed and solid in the blood, and coagulation is simply the result of the aggregation of these solid particles. Supposing it to be proved that the fibrin exists in a solid state in the blood, it yet remains to determine the cause of this aggregation in air. It has been said that the fibrin surrounds or exists in the globules ; since, however, we can separate the globules and still have a coagulable plasma, this hypothesis is not admissible. Smee considers fibrin as oxidized albumen. But how can it be supposed that this oxidation takes place in a few seconds ? Notwithstanding all that has been written concerning the probable cause of the coagulation of the blood, it must be confessed that the causes thus far assigned are not wholly satisfactory. They are, for the most part, mere hypotheses. Serum is chiefly a solution of albumen. But this albumen is found in different states, free and combined with soda ; also, in the analyses above cited, the albu- minoid substances (fibrogene and fibrino- plastic sub- stance,) which are precipitated by carbon dioxide, have been considered as albumen. E. Mathieu and Y. Urbain (9-79, 665 and 698) seem to have established, though disputed by A. Grautier (9-83-277), that the coagulation of blood is caused by the carbon dioxide, which, when blood is exposed to the air, is expelled from the blood globules, in which it is contained during life, by the oxygen of SERUM. 279 the air. Hence it is clear why alkalies and ammonium hydrate, as well as concentrated solutions of certain salts which absorb carbon dioxide, prevent the coagu- lation of blood. Yenous serum contains somewhat more water than that of the arteries, the serum of women containing, according to C. Schmidt, more water than that of men. The proportion of water increases in most diseases ; the reverse is seldom observed except in certain fevers and in cholera. The abundance of albumen in the serum and in the blood in general proves that this substance is the prin- cipal constituent of the albuminoid fluids and nitro- genous tissues of the body. Its proportion ranges between 63 and 70 in 1000 parts ; it increases at the moment of digestion. Yenous blood contains more albumen than arterial blood. Its quantity generally diminishes in disease ; yet it increases, as does the fibrin from other causes, in inflammatory fevers. The fatty bodies of the serum are often crystallizable, and it was a mixture of these substances which was formerly called seroline. There is a small quantity of olein and oleic acid in the serum. There is also found in it stearin, margarin, the two corresponding acids, and cholesterin. The venous blood contains more of this last body than the arterial blood ; the blood of the vena porta contains more than that of any other vessel. The amount of fatty bodies increases during diges- tion. They diminish in general during disease, with 280 ANIMAL CHEMISTRY. the exception of cholesterin, which often increases. The blood of women contains a little more than that of men. Griucose always exists in the serum ; its proportion is very small ; it increases during digestion if the food is very starchy. The blood of the hepatic veins contains a considerable proportion of this substance, while the blood of the vena porta hardly contains any whatever. The blood of diabetic persons scarcely furnishes 0.05 per cent ; normal blood contains at the most 0.0020 per cent. The blood which is most rich in salts is that of the vena porta ; arterial blood in general contains more than venous blood. A considerable diminution in the quantity of sodium chloride in food affects health seriously. Many other substances have been found in the serum. Some are constantly met with ; these are urea, uric acid, hippuric acid, creatin, creatinin, casein, acetic acid, dextrin, and glucose, the peptones, sodium and potassium chlorides, sodium carbonate and phos- phate, sodium and potassium sulphates. Neither glycocol, leucin, taurin, nor tyrosin has been found. Prevost and Dumas detected the presence of urea in the blood after the suppression of the urinary secretion. The existence of this body in the blood has been proved by Bechamp and other experimenters. According to Picard, normal blood contains 0.017 of urea ; twice as much is found in the renal artery as in the renal vein. THE COAGULTTM. 281 Casein exists principally in the blood of pregnant women, nurses, and nurslings. In leucocythsemia the blood contains gelatin, hypo- xanthin, lactic and formic acids : biliary acids in diseases of the liver, ammonium carbonate in persons having cholera. The coagulum — crassamentum or clot — is red and somewhat elastic. It is formed principally of fibrin and globules, and incloses about one-fifth of its volume of serum. It seems to form more rapidly in the blood of a child than in that of an adult, in that of women sooner than in that of men ; its com- pactness is in inverse proportion to the rapidity of its formation. In some pathological states the separation of the clot and serum does not take place, and a gelatinous mass remains. In others the blood is rich in fibrin, and a whitish matter called " buff," or buffy coat, is observed on the surface, which is fibrin nearly free from globules. On agitating coagulum in a bag placed in a stream of water the globules and other proximate principles, with the exception of the fibrin, are carried away by the water, and the latter remains in the cloth in the form of greyish filaments. Globules. —Blood globules may be obtained by receiving fresh blood in a saturated solution of sodium sulphate, then filtering ; the globules remain on the filter mingled with the solution of the salts. The red globules of the blood of mammalia are 282 ANIMAL CHEMISTRY. minute circular disks, slightly thickened at the margin. It is generally admitted that they are formed of a colourless membrane ; they would, therefore, be verit- able cells. Yet some observers regard them as an agglomerated gelatinous substance destitute of exterior membrane. This latter view is not probable, for on placing a drop of blood on the slide of a microscope and adding a little water the globules are seen to swell, also the margins become yellow in contact with a solution of iodine. According to Bechamp and Estor, there exists in the blood on leaving the body an immense number of movable granulations of extreme minuteness, capable of development, of uniting and even of changing into bacteria and bacterides. These microscopic beings — called microcosms —are said to form the globules by their aggregation^?) These savants affirm that they have seen them form new cells, and that the blood- globules in the body are the result of the activity of the microcosms. The blood-globules in fishes, reptiles, and birds have an elliptic form. Milne-Edwards has shown that no connection exists between the size of animals and the size of their blood-globules, but that they are smaller as the organ- ism is more perfect and respiration more active 6 Globules have a greater density than serum. Placed in contact with water they absorb the same, swell, and become spherical. At the same time a quantity of the colouring liquid of the globules is extravasated and GLOBULES. 283 colours the water. Change of form exerts a great influence upon their colour. On swelling, they take on a darker tint. On losing water they become clear and red ; this takes place when they come in contact with sugar and alkaline liquids. The globules cannot, therefore, be collected on a filter and washed with water without becoming altered. A solution of sodium sulphate of 18° Baume does not attack them, and if a mixture of one volume of blood and two volumes of this solution be thrown upon a filter, they may be sepa- rated from the serum without being destroyed. This result is better obtained by adding to defibrinated blood ten times its volume of a concentrated solution of common salt ; the globules are precipitated, and may be washed with salt water. Besides red globules there exist in the blood white corpuscles ; their number is much smaller (about 1 in 400). There appear to be two kinds. The most abundant, the plasmic, lymphatic, and fibrinous globules, have a spherical form. Their border is very well defined ; they contain a viscid matter in which float little nuclei, which refract light strongly. They are larger than the red globules (diameter =0.01 13 millimetre), also lighter than these latter. They may be distinguished from the coloured globules by their different reactions. Water distends without destroying them, and dissolves them only after a long time. Acetic acid simply causes them to contract. 284 ANIMAL CHEMISTRY. These globules are not, like the preceding ones, specially characteristic of the blood, for thej are found in most of the other fluids of the system. The name gtobulines has been given to certain white corpuscles, not numerous, whose diameter is about -j-^- of a millimetre. They are small spherical nuclei, which are probably derived from the chyle. The number of globules in a cubic millimetre of blood has been estimated at four to* five millions. ANALYSIS OF DKIED GLOBULES. Human Blood of a blood. dog. Haemoglobin . 86.79 86.50 Albuminoid -matter . 12.24 12.55 Lecithin 0.72 . 0.59 Cholesterin . .25 0.36 (Hoppe-Seyler) The albuminoid matters appear to be constituted chiefly, if not wholly, of fibrino-plastic substance. Bed globules treated with water become spherical and distended, the colouring matter and other elements pass into the water, and there remains a gelatinous mass of a pale tint called stroma, which is formed chiefly of albuminoid substances. Haemoglobin. — This substance is prepared by mixing defibrinated blood with an equal volume of HAEMOGLOBIN. 285 water, and adding to this liquid one-fourth its volume of 80 per cent, alcohol ; this mixture is allowed to stand twenty-four hours exposed to a temperature of 0°. Crystals then form in the liquid, which are pressed out on a filter and purified by re-dissolving in water and re-precipitating by adding to the solution one-fourth its volume of alcohol and exposing to a temperature below 0°. It may be easily obtained in an impure state by adding ether, drop by drop, to defibrinated blood. The colour of the blood darkens on account of the destruc- tion of the globules, and the liquid deposits crystals on exposure to a low temperature. This substance is also known as hcematocrystallin. The haemoglobin of human blood forms regular rec- tangular prisms ; the same is true of that of the dog, cat, horse, and lion. That of guinea-pigs and mice crystal- lizes in tetrahedrons, and that of squirrels in hexagons. It is insoluble in absolute alcohol, ether, chloroform, carbon bisulphide, and essential oils. Acids decompose it without dissolving. Alkalies dissolve it by altering its nature. It has a slightly acid reaction. It may be preserved after having been dried at a low temperature. In aqueous solutions it is slowly destroyed at ordinary temperatures, and instantly at 100°. It absorbs oxygen at ordinary temperatures, one gramme of haemoglobin dried at 0° absorbing more than 1 c.c. In a vacuum nearly the whole of this gas again escapes. Haemoglobin may therefore be considered as that constituent of the globules which fixes oxygen. E 286 ANIMAL CHEMISTRY. Haemoglobin contains, besides carbon, hydrogen, oxygen, and nitrogen, small quantities of sulphur and phosphorus, and about 0.5 per cent, of iron. Haematin — H^emin. — An aqueous solution of haemo- globin heated to about 75° or 80° is decomposed into another colouring matter, haematin, and an albuminoid matter which coagulates. This decomposition takes place gradually at ordinary temperatures, in presence of acids or alkalies in solution. Haematin represents only about four per cent, by weight of haemoglobin. If a small quantity of sodium chloride and strong acetic acid is added to haemoglobin or blood, and after having heated this mixture over a water-bath, it is allowed to slowly cool, hydrochlorate of haematin (haemin) is precipitated in rhomboidal crystals of a brown colour ; this is also a characteristic test in medico-legal investigations. Yirchow, also Robin, have designated as hcematoidin a crystalline matter, containing neither iron, sulphur, nor phosphorus, and which results from the destruction of haematin in sanguinary effusions. This body is, however, now generally recognized as bilirubin. Haemoglobin forms with carbonic oxide a crystalline compound, which may be prepared in the same manner as haemoglobin, by employing blood previously agitated with carbon oxide. These crystals have the same form as the haemoglobulin. F. Hoppe-Seyler (60-1874-1065) has lately care- fully investigated the colouring matter prepared from haematin, by reducing substances, and proved its IRON IN THE BLOOD. 287 identity with the urobilin of Jaffe (36-1869-815), and the hydrobiliruUn of Maly (36-1872-836). It should be observed that Thudichum and Kingzett have quite recently (32-' 76-255) made an analysis of hsemin, and finding the same to contain 7.65 per cent, iron, 3.02 chlorine, and 0.60 phosphorus, have come to the conclusion that haemin is in reality a substance consisting of hsematin, chlorhydrate of hsematin, and a crystalline compound containing phosphorus, which they regard as identical with myelin, a body claimed by Virchow as existing in the brain. C. Husson (9-81-477) states that crystalline com- pounds may be formed between hsematin and phenol, oxalic acid, valerianic acid, tartaric acid, citric acid, and silica. Haemoglobin forms crystalline compounds with nitrogen dioxide and cyanhydric acid. Eed globules are not attacked by albumen, gum, or sugar solutions, carbon dioxide, or neutral salts of the alkaline metals. Alum, chlorine, sulphuric acid, and nitric acid cause them to contract ; water, organic, and phosphoric acids, and alkaline solutions dissolve them. Milne-Edwards (9-79-1 268) remarks that the respira- tory power of the blood depends upon the number of red blood- corpuscles present. Iron in the Blood. — Boussingault determined this metal among the elements of cow's blood. In 100 parts he obtained : 288 ANIMAL CHEMISTRY. Total Mineral Substances. Iron. Dry fibrin . 2.151 grammes 0.0466 grammes Dry albumen . 8.715 „ 0.0863 „ Dry globules . 1.325 „ 0.3500 „ The colouring matter of tbe blood owes its colour mainly to tbe large proportion of iron in the globules, which, dried, gives : 10.750 per cent, ash, containing 9.043 „ ferric oxide, 1.707 „ other mineral substances, formed almost entirely of lime and phosphoric acid. P. Picard (9-79-1266) found the proportion of iron in the blood of dogs to be quite variable and pro- portional to the amount of oxygen the blood was capable of absorbing. In his investigations regarding the amount of iron in the human body, the spleen gave higher proportions than any other organ. Jolly has very lately (61 -'78) made analyses that appear to show that the iron in blood exists as ferrous phosphate. GASES OF THE BLOOD. Magnus was the first to make, in 1837, an extended study of the gases contained in the blood. A flask con- taining blood was agitated violently, in order to coagu- late the fibrin. The defibrinated blood was transferred GASES OF THE BLOOD. 289 into a bell glass, filled with mercury. He obtained the following composition of the gases liberated : — Venous Blood. Arterial Blood. Carbon dioxide Oxygen . Nitrogen 71.6 62.3 15.3 23.2 13.1 14.5 100.0 100.0 His methods of collecting the mixed gases were not, however, complete, and later analyses may be regarded as more reliable. C. Bernard determined the amount of oxygen in the blood, profiting from a fact discovered by him that carbon oxide displaces the oxygen. The blood is taken directly from the body by a syringe, and immediately introduced into a graduated tube half-filled with carbon oxide. This is agitated, and kept at a tem- perature of 40°, after which the amount of oxygen in the gas is determined. Yenous and arterial blood dissolve variable quanti- ties of oxygen. 100 volumes of blood from a young dog contained : In the left ventricle, 23.0 vol. of oxygen. Animal fasting. In the left ventricle, 17.6 vol. of oxygen. Animal digesting. In the right ventricle, 10.0 vol. of oxygen. Animal fasting. 290 ANIMAL CHEMISTRY. In the right ventricle, 10.2 vol. of oxygen, digesting. Animal The gases from the blood of a dog gave, in 100 parts : Nitrogen. Oxygen, , Carbon Carbon di- dioxide. oxide combined. Arterial rl.61 blood 12.30 20.05 34.8 traces. 22.2 35.3 0.88 Venous rl.32 12.1 43.5 4.40 blood 11.64 11.6 42.8 5.30 When venous blood is agitated with oxygen it takes on the red colour of arterial blood. ? If, on the contrary, arterial blood be agitated with carbon dioxide, hydrogen, or nitrogen, it assumes the dark brown tint of venous blood. P. Bert (9-80-733) found, in his investigations upon the power of blood to absorb oxygen at different pres- sures, that a compound of haemoglobin with oxygen (oxyhemoglobin,) is obtained when blood is agitated with air at ordinary pressure. Increase of pressure in- creases the proportion of oxygen in this compound ; it also remains constant until the pressure is lowered to one-eighth of an atmosphere at 16°, but at the tem- perature of the bodies of mammalia it decomposes as the pressure is further removed. The blood on leaving the lungs does not contain as much oxygen as it is capable of absorbing. Grrehant has found that in agitating blood with oxygen the quantity which it is capable of absorbing is to the ACTION OF OZONE ON THE BLOOD. 291 quantity ordinarily found in it as about 26 to 16. But there is a great difference in this regard between indi- viduals, their state of health, etc. The opinion has been expressed that the blood con- tains ozone, but this cannot be admitted, as the blood, like all organic matter, destroys ozone. It is only necessary to agitate blood in a vessel with ozone to obtain proof that these two bodies are incompatible, for the odour of ozone disappears immediately. J. Dogiel (75-24-431) states, as the result of his recent researches regarding the action of ozone upon the blood, that the action of the ozone is chiefly upon the red blood-corpuscles; their colouring matter is expelled, and they become darker within fifteen minutes. After this change alcohol, ether, or chloroform pro- duces no separation of crystals of haemoglobin. Upon passing ozone through defibrinated blood for a long time, flakes separate out, which, after washing with water, are not to be distinguished from fibrin. By continued action of ozone blood becomes first of a dirty, yellowish-green colour, and, finally, colourless. Hsema- tin is likewise rendered colourless by ozone. Blood poisoned with carbon oxide attains in a short time the properties of normal blood on exposure to the action of ozone, carbon dioxide being given off. Blood contain- ing carbon oxide is discoloured less quickly than normal blood, and does not so quickly lose its property of depositing crystals of haemoglobin. The change of the blood corpuscles produced by ozone should not be confounded with the change produced by carbon dioxide. 292 ANIMAL CHEMISTRY. Carbon oxide displaces the oxygen of the blood, and is very deleterious when inhaled. Chlorine coagulates blood, removes the iron which enters into the composition of its colouring matter, and subsequently destroys the organic matter. The iron is changed into ferric chloride, capable of being detected with reagents. Arsenide of hydrogen completely changes the nature of blood, which assumes the colour of ochre. Defibrinated blood becomes brown and then dark green under the action of hydrogen sulphide; the colouring matter is attacked and the globules de- stroyed. Certain neutral salts, the alkaline sulphates, phos- phates, and nitrates, redden the blood in the same manner as oxygen. Ore (9-31-833, 990) asserts that acetic acid, sul- phuric acid, nitric acid, hydrochloric acid, phosphoric acid, or alcohol after being diluted with water, may be injected into the blood-vessels of a living animal with- out producing coagulation of the blood. DIFFERENCES BETWEEN ARTERIAL AND VENOUS BLOOD. We have incidentally noticed these differences in studying the various constituents of the blood. Longet sums them up as follows : INDUSTRIAL USES OF BLOOD. 293 Arterial Blood. 1st. Vermilion red. 2nd. Rich in fibrin. 3rd. „ „ globules. ? 4th. 5th. 6th. 7th. 8th. , , , , SclltS. Contains about 30 parts of oxygen to 100 of carbon dioxide. More coagulable. Less abundant in fatty matters. ? Has the same com- position in all parts of the arterial system. 4th. 5th. 6th. 7th. 8th. Venous Blood. 1st. Brown red. 2nd. Rich in albumen. ? 3rd. Has less water. „ „ extractive matters. Contains about 22 parts of oxygen to 100 of carbon dioxide. Less coagulable. Grlobules more abun- dant in fatty matter. ? Has a different com- position in different parts of the venal system. We have indicated by ? such items in Longet's tabula- tion as are doubtful, or at least are not constant. Industrial Uses of Blood.— Coagulated blood serves as food in certain countries, as Grermany, Sweden, and Italy. Freshly drawn blood is highly nutritious, and not unfrequently used by emaciated and greatly enfeebled invalids. The large quantity of albumen contained in the blood and the property which albumen possesses of coagulating on heating, causes blood to be employed in sugar refineries for the clarification of 294 ANIMAL CHEMISTRY. CHEMICAL PATHOLOGY OF THE BLOOD. Since the blood circulates throughout the entire body, it is evident that diseases which manifest them- selves at any point necessarily produce modifications in the blood, hence it may be asserted that an examina- tion of the blood furnishes a valuable basis of dia- gnosis. Yet, from the fact that only blood taken from a superficial vein can be experimented with, and that the blood becomes contaminated in its passage through the body, the small quantity, therefore, of abnormal or noxious matter is often found to be too slight for the determination of its amount, or in some cases even for its detection. The chemical facts which we possess in regard to the variations of the blood in different diseases are few. It is only known that in such and such states there is a diminution or increase of this or that principle. We are not sufficiently informed as to the genesis of these substances to be able to decide, whether the morbid condition appertains to one organ rather than to an- other, or whether the disease is due to a given cause or to some other. The proximate principles of the blood may also seem to increase, without this increase being either real or as great as would appear ; this may be due to a diminution in the total mass of blood. ANOSMIA. 295 Plethora. — Plethora may be due either to an increase in the proportion of globules, or an augmenta- tion in the volume of the blood ; therefore we distin- guish between globular and sanguinary plethora. In the former the globules increase. In sanguinary plethora — that is, in the augmentation of the mass of the blood — the reverse occurs, as the quantity of blood may increase in greater proportion than the globules. Anosmia. — Here also there may be either diminution of the mass of the globules or a diminution in the total amount of the blood. In the first case, an increase of water and fibrin is noticed in the blood, and often the number of colourless globules increases. The clot is firm and often produces « buff." The anaemic state occurs when the body does not repair the losses which it has undergone ; it is pro- duced during growth, at the time of puberty, or after diseases which impede digestion. Iron and its prepa- rations have a very favourable influence on the develop- ment of globules. We have just stated that certain anaemic conditions correspond to an increase of colourless globules. The spleen then increases in size ; the blood which remains in the spleen is very rich in white globules, contain- ing 1 to 49 of the coloured globules. The blood of the splenic vein also contains large numbers of these globules. The coagulum of the blood of this vein is 296 ANIMAL CHEMISTRY. but slightly compact ; the serum which separates there- from coagulates after a short time. The following hypothesis based upon these facts has been proposed: The spleen is an organ which destroys red globules, changing them into white globules which are carried along into the circulation and afterwards again transformed into red globules. These views are, however, not regarded as established. Leucocythjemia. — This name is given to a morbid state characterized by the abundance of white globules : the number of these may amount to one-fourth and more of the total number of globules. The blood is then milky, and often acid from the formation of acetic or lactic acid. Cholera — Typhoid. Fever. — The globules assume irregular forms, and unite together during cholera and typhus. In this latter disease, and in tuberculosis in its advanced stages, the blood loses its property of becoming red in contact with oxygen, since this gas no longer unites with the globules. The blood of typhus patients contains ammonium carbonate, pro- duced by the transformation of urea, and it is probably this compound which leads to the alteration of the globules, as the same phenomenon is observed when ammonia is introduced into the blood. Ammonia and many toxic agents attack the enve- lopes of the globules ; hence, whenever these substances are present in the blood, the globules become ruptured, and death ensues in the absence of prompt antidotes. The blood is thick, and resembles gooseberry jelly in DISEASES IN WHICH THE FIBRIN DIMINISHES. 297 cholera ; globules, as well as albumen and extractive substances abound. The serum is deficient, is dense, and generally poor in salts, jet the potassa compounds and phosphates increase. As the urinary secretion is diminished or suppressed, the urea increases in the blood, and there is produced ammonium carbonate. Scurvy. — The change in the blood is quite marked in this morbid state. It is disorganized on account of the dissolution of the globules, and the diminution of albumen and salts. Albuminuria. — The blood does not seem to change in the amount of fibrin. The proportion of globules and albumen is greatly diminished. Dropsy. — The globules and albumen diminish, and the serum is extravasated. Inflammatory Diseases. — The fibrin increases in these affections, in pleurisy, pneumonia, and acute articular rheumatism. The proportion of this body, which, in normal blood, is 2 to 2.3, rises to 7.8 and even 9 parts in 1000. The fatty matters augment, and the albumen and globules diminish slightly. The blood is charged with carbon dioxide, which fact explains the retarding of the coagulation, as a large proportion of this gas prevents coagulation. Diseases in which the Fibrin Diminishes. — When food is insufficient, also in cases of syphilis, in prolonged suppuration, in typhoid fever, and in scurvy, the fibrin generally diminishes, or loses its property of coagulating. The coagulation of the blood is very slow in diseases of the respiratory organs, when the hematosis is incom- 298 ANIMAL CHEMISTRY. plete, and after death by syncope. It does not occur in. the blood of persons asphyxiated, killed by lightning, or poisoned with cyanhydric acid, narcotics, hydrogen sulphide, or ammonia. Usually in a fatal* result there is a complete destruction of the globules. In this case, oxygen ceased to unite with the blood, and the serum becomes coloured. The blood of persons who have died from the bite of a serpent coagulates very rapidly. It should be remarked that a decrease in the amount of fibrin in the blood does not always occur in the cases as cited above, and, indeed, it is claimed by Gorup-Besanez (21-364) that in no disease whatever is there uniformly a diminution in the fibrin. Variation in the Albumen. — The blood becomes poor in albumen under a great many circumstances : after loss of blood, prolonged suppuration, in albuminuria and dropsy, in malarial fevers, in typhoid fever, and scurvy. The albumen seems to diminish in proportion as the fibrin increases. Variations in Alkalinity. — Normal blood is alkaline This alkalinity increases in typhoid and putrid fevers, which is probably due to the formation in the blood of ammonium carbonate from urea. The blood has been known to become acid after an abnormal production of lactic acid. The globules are then dissolved by this body, and death rapidly ensues. The alkalinity seems to diminish in inflammatory diseases. Variations in the Fatty Bodies. — The drinking of large quantities of fluids augments the proportion of the fatty bodies, and it seems certain that corpulent VARIATIONS IN SUGAR. 299 persons would grow thin on diminishing the quantity of liquid which they imbibe. The fatty matters generally augment during affec- tions of the liver, in phlegmasia, Bright's disease, and in the first stage of some acute diseases. Z. Pupier (9-80-1146) has lately found by extended researches that the use of sodium bicarbonate or alkaline mineral waters tends to increase the number of red blood-corpuscles both in man and animals. Other Variations. — The extractive vnatters become abundant in puerperal fever and scurvy. Claude Bernard recently (9-83-407) set forth the following, based upon his investigations regarding the quantity of sugar in the blood. The sugar of the blood is soon decomposed on the removal of the latter from the body. After death the sugar also rapidly decomposes, even when retained \v the blood-vessels. The presence of sugar is independent of the nature of the food ; in the arteries it is uniform in quantity, while in the veins, except in the hepatic, though variable, it is yet less than in the arterial system . The amount of sugar increases in diabetes. To extract the sugar of the blood, the latter is first defibrinated. To the serum is ao'ded its triple volume of alcohol ; the coagulum is separated and washed with water containing an equal volume of alcohol. It is now evaporated to dryness, and the residue treated with alcohol, which dissolves the sugar. V. Eeltz (9-80-553, 1338) recently ascertained by his investigations upon the action of putrefying blood upon animals, that injection of the same into a vein of 300 ANIMAL CHEMISTRY. an animal produced septicemia. The poisonous pro- perties of putrefied blood are not changed by passing air through the same, but are lessened by the action of pure oxygen. If the gases of the blood are removed with a pump and the blood allowed to remain in a vacuum for some time, it loses its poisonous properties. Feltz is of the opinion that the poisonous body is a gas. In all stages of putrefaction, even after being dried in the air, blood retains the property of produc- ing septicaemia. Uric acid'is sometimes observed to increase in the blood. The blood of icterical persons contains the colouring matter and other constituents of the bile. Urea accumulates in the blood when the kidneys perform their functions badly ; this condition is known by the name of urcemia. The urea which accumulates in the blood is partially decomposed, producing ammonium carbonate. Von Grorup Besanez (75-23-135) found in the blood of a man suffering with atrophy of the liver, besides the normal constituents, a body closely related to gluten, but very different in its optical properties, hypoxanthin in not inappreciable quantity, formic acid, and volatile fatty acids, rich in carbon, also a non- volatile strong organic acid, soluble in water, alcohol, and ether, which, however, is not lactic acid. Uric acid, xanthin, leucin, and tyrosin could not be found. The proportion of salts diminishes in intermittent fevers, scurvy, Bright's disease, dysentery, and typhoid states. It augments in intermittent fevers and cholera. RESPIRATION. 301 EESPIEATION. The atmosphere penetrates certain special organs, which are the • lungs in man, branchia in fishes, and trachea in insects. There is thus established a continual exchange between the blood and the air, which is called respiration. The oxygen of the air coming in contact with the membranous walls of the respiratory organ, which are very thin and very permeable, traverses them aud penetrates the blood. It is not dissolved in the serum of this liquid, but it fastens itself upon the globules, and forms with their substance a very unstable combi- nation. Inversely, the carbon dioxide and aqueous vapour on reaching the lungs in the venous blood escape through the same membranes, and are exhaled into the atmosphere to be again shortly decomposed by the green portions of plants. 302 ANIMAL CHEMISTRY. THEOEY OF BESPIKATION. Different methods have been employed for studying the phenomena of respiration. Lavoisier was the first to solve the problem; his method, which has since been perfected by Regnault and Eeiset, consists in placing the subject to be experimented upon in a known volume of oxygen, absorbing the carbon dioxide ex- haled and renewing the oxygen, in a continuous manner. A second method consists in placing the subject in a confined space and analyzing this air> determining the volume of gas exhaled at each expiration, counting the number of respirations made during a certain time, and analyzing the air exhaled during this time. By this method absolute results cannot be obtained, as nitrogen is also exhaled during respiration, and thus we have two unknown data : the weight of the nitrogen exhaled, and that of the oxygen consumed to form water. Boussingault made use of an indirect method, which consisted in feeding the animal in such a manner that its weight remained constant, also weighing and analyz- ing the food, as well as the excrements, and subtract- ing the weight of the latter from the former. It is clear that the difference between these two weights represents what had been lost by pulmonary and cutaneous respiration. THEORY OF RESPIRATION. 303 Boussingault experimented on horses, cows, and doves. The quantity of oxygen consumed is proportional to the energy with which the vital functions are executed. Dumas, experimenting on himself, found that the absorption of oxygen was at the maximum 23 litres or 33 grammes per hour, or about 800 grammes for 24 hours ; 13 litres of carbon dioxide are produced ; the air expired contains 4 per cent, of this gas. Substantially, the amount of oxygen consumed varies between 20 and 25 litres per hour, or 29 to 36 grammes for an adult man in a state of repose. We are indebted to Scharling, Andral, and Gravarret, also to Pettenkolfer, Eegnault, and Eeiset for important researches on respiration. The apparatus of Scharling consists of a chamber of one cubic metre capacity, made absolutely tight by a covering of sized paper. The subject is placed in this for half an hour to one hour. The air enters the chamber through an orifice in the lower portion, and is drawn in by £ water aspirator. The products of respi- ration pass into a series of flasks, the first of which contains sulphuric acid, which retains the moisture, the remainder containing alkaline substances to absorb the carbon dioxide formed. Two important objections to this method may be stated. The air is not sufficiently renewed, and the chamber is too small. It results, therefore, that the air of the box becomes charged with carbon dioxide and aqueous vapour, and becomes elevated in temperature 804 . ANIMAL CHEMISTRY. in an unnatural manner. These circumstances exert a deleterious influence upon respiration, and must neces- sarily bring about abnormal conditions. Scharling found that in the respiration of a man 34 grammes or 17 to 18 litres of carbon dioxide are pro- per hour. Andra'l and Gavarret took special care not to effect any modification of the normal conditions of respiration. A mask of thin copper, the edges of which were furnished with a cushion of caoutchouc in order to prevent any escape of gas, is fixed firmly to the face of the subject, which it covers without binding. This mask is large enough to receive the product of an entire respiration, and opposite the eyes it is j)ierced with two orifices closed with glass. The air penetrates the mask by two tubes, which enter the mask at the height of the corners of the lips. The air expired does not pass out through these tubes, as they contain two little balls of elder-pith, which serve as valves. The air escapes through an opening situated opposite the mouth, and enters into three flasks, from which the air has been exhausted, and whose capacity is 140 litres. The chief difficulty consisted in regulating the open- ing of the cock which separates the flasks from the opening in the mask, in such a manner that respiration could take place easily, both for inspiration and expira- tion. The operation lasted from eight to thirteen minutes, and the gas collected was about 130 litres. THEORY OF RESPIRATION. 305 The cock was closed, the air was permitted to cool in the flasks, and the pressure and temperature determined. Then these flasks were placed in connection with three others exhausted, but separated from the first by tubes arranged for absorbing moisture and carbon dioxide. The gas was made to pass through the tubes slowly by opening progressively the cocks, and when the gas ceased to pass through the tubes the pressure in the first flask was again measured, the difference giving the amount of air which escaped. The increase in weight of the tubes containing the alkaline solutions represents the amount of carbon dioxide in this air. The experimenters operated on 37 men and 26 women of various ages, with results which we will now state. The respiratory phenomena attain their maximum energy at about thirty years of age ; they increase up to this age, then decrease until death. From 20 to 30 years the quantity of carbon dioxide exhaled is 18 to 20 litres per hour. Respiration is more active in men than in women. The production of carbon dioxide is greater during digestion than when fasting ; the relation increases from 24 to 33, and even more. At the age of puberty there is a great increase in the production of carbon dioxide in man. This increase is arrested in woman at the age when menstruation sets in, and returns during several years after the critical age. It likewise increases during gestation. Respiration is feebler during sleep, and, according to Scharling, the quantity of carbon dioxide produced during sleep is one-fourth less than when awake. 306 ANIMAL CHEMISTRY. Exhaled air contains aqueous vapour ; this fact was observed by the ancients, for, on breathing upon glass, or other polished surface, a condensation of droplets of water was observed. This water was considered as exclusively derived from that introduced into the body with the food. Lavoisier distinguished water of pulmonary transpiration, proceeding from the lungs, from the water of respiration formed by the combination of oxygen with hydrogen. According to Valentin, the weight of water exhaled from the lungs during 24 hours is, in the mean, 540 grammes, whiie, according to Barral, it attains to nearly 650 grammes. It seems certain that expired air removes from the body a small amount more of nitrogen than the air in- haled introduces. According to Edwards, animals absorb nitrogen from the air, and disengage a small quantity of the nitrogen of their own substance. The researches of Regnault and Reiset, however, have demonstrated that the nitrogen of the air is not ordinarily absorbed during respiration, and, consequently, does not assist in nutrition under normal conditions. Among other principal conclusions of their important investigation were the following : — 1st. When warm-blooded animals are submitted to their habitual alimentary regimen, they always dis- engage nitrogen ; but the quantity of this gas is very small ; it never amounts to more than -^-^ of the weight of oxygen consumed, and is often less than t ±-q. 2nd. When the animals are in a state of inanition they often absorb nitrogen, and the proportion varies THEORY OF RESPIRATION. 307 between the same limits as that of the nitrogen exhaled in the case where they are subjected to their natural regimen. The absorption of nitrogen almost always occurs in starving birds, but very rarely in mammalia. 3rd. The relation between the quantity of oxygen contained in the carbon dioxide and the total quantity of oxygen consumed seems to depend much more upon the nature of the food than upon the class to which the animal belongs. This proportion is greater when the animals are fed with grain, and in this case exceeds the normal or unity. When they are fed exclusively with meat, this proportion becomes less, and varies from 0.62 to 0.80. With a diet of vegetables, the relation is in general intermediate between the two just given. 4th. The relation between the oxygen contained in the carbon dioxide and the total oxygen consumed varies for the same animal from 0.62 to 1.04, according to the diet to which it is subjected. It is therefore far from being constant. 5th. The quantities of oxygen consumed by the same animal in equal times vary much, according to the different periods of digestion, the amount of activity, and many other circumstances. With animals of the same species, and of the same weight, the consumption of oxygen is greater in young than in adults ; it is greater in lean healthy animals than in very fat ones. 6th. Warm-blooded animals disengage by respiration small and almost indeterminable quantities of ammonia and sulphuretted gases. 308 ANIMAL CHEMISTS,!. 7th. The respiration of animals of different classes in an atmosphere containing two or three times as much oxygen as normal air presents no difference from that which takes place in our terrestrial atmosphere. The consumption of oxygen is the same ; the relation between the oxygen contained in the carbon dioxide and the total oxygen consumed undergoes no perceptible change ; the proportion of nitrogen gas exhaled is the same, and the animals do not seem to perceive that they are in an atmosphere different from the ordinary one. In the recent experiments of Bert, he observed that if an animal be exposed to the influence of pure oxygen under a pressure of four atmospheres, it gives signs of discomfort, which are followed by violent convulsions, and death ensues if the pressure be increased to five atmospheres. It is to the action of the oxygen and not to the increased pressure that these effects are to be attributed ; for if a swallow be exposed to air under a pressure of three atmospheres, and then nitrogen at twenty atmo- spheres admitted, the animal perishes, slowly asphyxi- ated, without convulsions. The convulsions also ensue if the oxygen under four atmospheres pressure be replaced with air under twenty atmospheres. The analysis of the gases of the blood shows that when death ensues the blood, instead of containing 18 to 20 c.c. of oxygen in 100, as in ordinary conditions, contains 35 c.c. An unusual combustion does not take place, for the temperature of the animal seems to fall sensibly, or at least it does not increase. SUMMARY OF THE THEORY OF RESPIRATION. 309 On the other hand, when the pressure of the air is diminished until death ensues, the bird perishes asphyxiated in the midst of a pure air hardly con- taining any carbon dioxide. Then -death takes place because the pressure of the oxygen is not sufficient to maintain in the blood the quantity necessary for pro- ducing vital phenomena. Thus an aeronaut would be able to mount without danger to much greater heights than have hitherto been reached if he would inhale oxygen when suffering from the rarefaction of air. On the other hand, divers would be able to work at great depths without danger if, instead of sending them pure air, a mixture of air and nitrogen of definite proportions were supplied. SUMMARY OF THE THEORY OF RESPIRATION. Priestley was cognizant of the fact that air and oxygen — which latter element he had just discovered — had the property of reddening venous blood, and that carbon dioxide turned arterial blood to a brown colour. But, misled by the phlogistic theory, he did not have the satisfaction of establishing the theory of respiration and combustion — an honour which belongs entirely to Lavoisier. This theory enabled the latter chemist to explain animal heat, and in 1789 he wrote the following: — " Respiration is simply a slow combustion of carbon 310 ANIMAL CHEMISTRY. and hydrogen which is similar, on the whole, to that which takes place in the name of a candle. Animal organisms are thus true combustibles, as they are oxidized in respiration and consumed at the expense of the oxygen of the air." As to the part of the body in which the combustion took place, he did not claim to make any assertion. Lagrange was the first to state that combustion takes place in the capillaries, and since then many investigators have established, by experiment, the truth of this assertion. In order to show, however, that the change in the colour of the blood takes place in the lungs, we have only to observe the lungs of a frog after having, by appropriate dissection, exposed them to view. The transparency of the membranes admits of the difference in the colour of the blood being plainly seen before and after leaving the lungs. The air produces this change, for if, as was done by Bichat, a cock be adapted to the carotid artery of a dog, the blood, which is red, becomes black when air is prevented from entering the lungs by closing a cock placed in the trachea ; and the red colour returns as soon as air is allowed to enter. The fact, perfectly demonstrated above, in regard to the relative insufficiency of oxygen and the abundance of carbon dioxide in the venous blood as compared with arterial blood, proves indirectly that an absorption of oxygen and a production of carbon dioxide takes place in the capillaries situated between the arteries and THE BLOOD AND ATMOSPHERIC OXYGEN. 311 veins. But Spallanzani, and especially W. Edwards, have directly proved this important fact. The latter removed the gases from the lungs of a frog by com- pressing them under mercury, and introduced the animal under a bell-glass filled with hydrogen over mercury. The frog breathed for quite a long time ; the analysis of the gases showed that they contained a volume of carbon dioxide much greater than that exhaled by the animal under ordinary conditions. Oxygen. — Oxygen is not merely dissolved by the blood. If such were the case, the blood of persons living in mountains would contain less than that of those who live in the lowlands. Nothing of this kind has been observed at Quito (2,908 metres above the level of the sea), at Potosi (4,166 metres), or at Deba (4,812 metres) ; in the latter place, the atmospheric pressure is scarcely half of that at the level of the sea, and consequently the blood should contain but half the amount of oxygen. On the other hand, Eegnault and Reiset have observed that the absorption of oxygen does not increase when animals respire an atmosphere con- taining two or three times as much oxygen as ordinary air. It is well known that the quantity of any gas dis- solved is directly proportional to the pressure which the gas sustains. On the other hand, the coefficient of solubility of oxygen in the blood at 15° is 0.0287, or very nearly that of oxygen in water ; and it is the same for serum. Hence it results that one litre of blood should dissolve 312 ANIMAL CHEMISTRY. only ^- of oxygen, or 5.7 c.c., while the real amount contained in the blood is 92 to 95 c.c. (Fernet) . It is therefore probable, d priori, that oxygen forms a combination with one of the principles of the blood. This principle is not the serum ; for if the blood be defibrinated and the globules removed, the serum dissolves scarcely more oxygen than water. If, on the contrary, defibrinated blood containing the globules be agitated with oxygen, it absorbs much more oxygen than the serum deprived of globules. If the globules simply dissolved the oxygen, the proportion would increase as the temperature decreased ; but this is not the case. At 40° to 45° a maximum absorption is observed, and at a higher temperature the phenomena of oxidation take place. A combination is therefore produced, and it follows from what we have said above that the haemoglobin of the globules must be the agent which effects the combination with the oxygen. This combination is also extremely unstable, as the oxygen may be almost completely removed in a vacuum. The oxygen of the blood acquires an energetic oxidizing power, comparable to that of ozone, at a tem- perature where ordinary oxygen is inactive. In fact, essence of turpentine, to which a few globules of arterial blood are added, turns litmus at once blue, in the same manner as when agitated in the air in the sunlight. Hydrogen peroxide dissolves pyrogallic acid without becoming coloured; but if to this solution platinum black or blood globules be added the brown coloration is at once produced. THE BLOOD AND CARBON DIOXIDE. 313 The blood contains, besides oxygen combined with the globules, a small proportion of this gas dissolved in the serum. It should be also stated in this connection that a small portion of the oxygen inhaled is employed to oxidize the sulphur of complex sulphur compounds, the albuminoids, etc. Carbon Dioxide. — Carbon dioxide is not, like oxygen, combined with the globules. Fernet has determined the quantity of this gas which the con- stituents of the serum — water, carbonate, phosphate, and chloride of sodium — are capable of absorbing, either by dissolving or combining with it ; and the result of these researches shows that the quantity of carbon dioxide found in the blood is very nearly equal to that which the serum alone absorbs. The quantity of carbon dioxide exhaled is less during sleep than when awake, for, as the organs are at rest, the oxidation is not then so great. The carbon dioxide is not derived from the atmo- sphere, since the gases exhaled contain more than the air, and its proportion, which is small in arterial blood, is observed to increase as this liquid traverses the organs in which the combustion takes place. This gas is therefore formed in the body, and is rejected as a waste product. F. M. Eaoult (9-82-1101) finds, as a result of recent experiments, that the presence of carbon dioxide in inhaled air causes a diminution of the carbon dioxide exhaled, and therefore in the oxygen consumed. 314 ANIMAL CHEMISTRY. Nitrogen. — Nitrogen forms at the most one-tenth of the gases of the blood, which contains 2 to 3 per cent, of this gas, while the serum dissolves only 1 per cent. ; consequently there is for this gas a special action not as yet explained. To review, the vesicles of the lungs act as a porous membrane ; and this organ should be regarded as an apparatus for the exchange of gaseous bodies. The blood which has become red in the lungs retains this colour until it enters the capillaries. On leaving the capillaries it is darker, and instead of oxygen it contains carbon dioxide. Consequently it is in this transit that the combustion takes place. This combustion either occurs in the capillaries proper, or the oxygen traverses their dialyzing walls and penetrates into the depths of the tissues whence the carbon dioxide escapes. This latter hypothesis is more in favour than the first. There is an exchange of gases in the centre of these structures as in the lungs, and the oxygen coming from the air penetrates into the innermost parts of the body of animals, and there effects the oxidation of the tissues themselves. VARIATIONS IN THE GASES EXPIRED IN PATHOLOGICAL STATES. We have but little information on this point. According to Hervier and Saint-La^er " the proportion of carbon dioxide decreases in all diseases in which GASES EXHALED IN PATHOLOGICAL STATES. 315 respiration is impeded, as in pulmonary phthisis, pneu- monia, pleurisy, pericarditis, eruptive fevers, and typhoid affections." In diabetes, chlorosis, anaemia, and in diseases in which there is no febrile movement, the variations in the proportion of carbon dioxide are hardly appre- ciable. In inflammations the carbon dioxide increases in a remarkable manner. Hayer, and afterwards Doyere, have affirmed that the air exhaled by cholera patients contains more oxygen and less carbon dioxide than the air normally expired. The quantity of oxygen absorbed is always greater than that of the carbon dioxide exhaled. 316 ANIMAL CHEMISTRY. NUTRITION. Animals canno't live unless able to respire and obtain nourishment, i.e., to ingest matters which are digested, absorbed, transported to the blood and sub- mitted, subsequently, to the action of oxygen. The food, carried by the blood into the different organs, undergoes therein two different changes. One part is burned, as coal in the furnace, producing heat and physical energy. The remainder becomes organized to form the tissues, since an animal, considered even in an adult state, and at a period at which its weight does not vary, constantly fixes matter in its organism, and therefore also loses an equivalent amount. ANIMAL HEAT MUSCULAR POWER. These two subjects are intimately connected with one another, and with respiration. The temperature of animals, and even that of plants, is not uniformly that of the medium in which these beings live. It varies also with the species. In man it is very nearly 37 degrees, in whatever climate he may live. ANIMAL HEAT MUSCULAR POWER. 317 The two extremes of temperature in which man can exist are very remote. He alone is capable of dwelling in all latitudes, in the most varied climates, and at heights so great that the pressure is only one -half of that at the level of the sea. Different portions of the body have not the same temperature. The exterior parts, from the cooling effect of the surrounding medium, are reduced in temperature 4 to 5 degrees below that of the interior. The muscles are 1.5 to 2 degrees warmer than the cellular tissue. It is the blood which, traversing the whole body, tends to equalize the heat disengaged in the different organs. The liberation of gases in the lungs lowers their temperature slightly, and especially that of the left cavities as compared with the right. The venous blood in the extremities is slightly less warm than the arterial blood, but this is due to the external position of the vessels. The conditions which cause the activity of the respiration to vary, that is, the absorption of oxygen, produce also a corresponding variation in animal heat. The temperature of the body of an infant or an old man is less than that of an adult, and we have observed that the respiratory phenomena diminish in energy at the two extreme points of life. If an important reduction in temperature is pro- duced after eating, it must be attributed to the fact that the blood rushes to the muscles of the digestive apparatus, which act with increased energy at this time. 318 ANIMAL CHEMISTRY. Like the fuel of an ordinary engine, a part heats the animal machine, the other is converted into mus- cular activity, which produces either external work (walking, movements of the arms, head, etc.), or in- ternal work (digestion, assimilation, etc.). Thus the observed heat is equal to the difference between the heat produced and the heat which is transformed into work. Now, since we know the mechanical equivalent of heat, that is, the quantity of work which a certain amount of heat will accomplish, the heat produced can be measured. If the muscle contracts without producing mechanical effect, the heat developed will be greater, since there is only heat developed, and that not utilized in the form of work. But even if the muscular power does produce an external mechanical effect, there is still in addition a production of heat in the interior of the body. Ex- periment has shown that when a muscle contracts the quantity of oxygen consumed is greater than when it is in repose: thus 100 volumes of blood, leaving a muscle which is in action, instead of furnishing 6 volumes of oxygen, furnish only 2 volumes. All chemico-physiologists are in accord in admitting that heat and motion are due to the oxidation of the food. The amount of carbon dioxide exhaled does not indicate the amount of oxidation which has taken place in the body. Every movement, every chemical action, every passage of the food from a solid to a liquid state in the blood, all friction of the liquids in the body, are actions which go to produce an ANIMAL HEAT — MUSCULAR POWER. 319 elevation or decrease of temperature. Consequently there are incessant gains and losses of heat, and we perceive, on the whole, only the resultant of these different actions of which the complexity is extreme. The carbon dioxide is not the only product of oxida- tion ; water and other matters (urea, uric acid, etc ) are formed, which escape in the different excretions. And the whole of the oxygen which oxidizes is not derived from the air ; a considerable part is obtained from the oxygen of the food itself. There is a difference of opinion as to the manner in which the action is produced. According to some, it results from the oxidation of the aliments as they are found in the blood. Others do not admit that the process takes place in the blood, but that it is a direct oxidation of the muscles by the oxygen which produces heat and motion. The second view is that most generally admitted ; nevertheless, the recent researches of Meyer and Frank- land on this subject appear to prove the contrary. An average man has about 7.5 kilos of muscles, considered in a dry state. According to Meyer, they would be completely oxidized in eighty days if they served to produce mechanical work. It is rational to regard the muscles as instruments for the transformation of potential energy into motion. We can only give a few conclusions deduced from the work of Frankland. 1st. The muscle is a machine destined to convert potential energy into mechanical force. 320 ANIMAL CHEMISTRY. 2nd. The mechanical force of the muscles is derived principally, if not wholly, from the oxidation of the substances contained in the blood, and not from the oxidation of the muscles themselves. 3rd. In man the principal substances employed in the production of muscular power are non-nitrogenous ; but nitrogenous substances may also be employed for the same object, hence the great increase in the evolu- tion of nitrogen under a diet of animal food, even with no increase in the amount of muscular work performed. 4th. Like all other parts of the body> the muscles are constantly being renewed ; but this renewal is not apparently more rapid during great muscular activity than during comparative repose. 5th. After a sufficient quantity of albuminous sub- stances has been digested for the renewal of the tissues, the best food for the production of work, both internal and external, are the non-nitrogenous substances, such as oil, fat, sugar, starch, gum, etc. 6th. The non-nitrogenous portions of the food which enter into the blood transform all their potential energy into effective force ; the nitrogenous substances, on the contrary, leave the body, taking with them a part (one- seventh) of their potential force. 7th. The transformation of dynamical force into muscular power is necessarily accompanied by a pro- duction of heat within the body, even when the muscular force is exerted exteriorly. This is, without doubt, the principal though not the only source of animal heat. TRANSFORMATION OF ALBUMINOID SUBSTANCES. 321 Fick and Wislicenus, in an ascension of the Faulhorn in 1865, determined the amount of work performed by their muscles, and the quantity of muscular matter oxidized to produce this work. This latter calculation was made by determining the amount of nitrogenous matters in the urine emitted, and collecting them in the form of urea, and based upon the fact established by Frankland, that 1 gr. of dried muscle transformed into urea produces 4,368 heat units. They arrived at the result that the work accomplished was about twice as great as that which would be produced by the com- bustion of the substance of the muscles transformed into urea. TRANSFORMATION OF FOOT) JN THE BODY- We recognize three principal classes of food, albumi- noid, farinaceous, and fatty. Transformation of Albuminoid Substances. — It was formerly believed that albuminoid matters were not modified in the body, but simply fixed in the tissues, and taking no part in the respiratory phenomena. The name of plastic food given to these bodies illustrates perfectly this manner of regarding them. On the other hand, the fatty and farinaceous bodies were thought to take part in the production of the respiratory pheno- mena alone. Hence the name respiratory aliments, which has been given them. This view, however, is too limited ; carbon dioxide and water are the principal but not the only products exhaled. Others are formed, as urea, uric acid, and these substances are nitrogenous. There 322 AN1MAT, CHEMISTRY. escapes also in the gas exhaled by the lungs a certain quantity of free nitrogen. It is well known that the framework of animal tissues is nitrogenous ; but it is none the less certain that different tissues are filled with non-nitrogenous matters, such as the fat of adipose tissue and jlycogenous substances. The albuminoid matters undergo in the blood, and afterwards in the organs to which the blood carries them, numerous transformations, most frequently pro- duced by oxidation. To prove this it will only be sufficient to enumerate the different nitrogenous principles found in the body. These are mainly : — [ Urea I Uric acid Urine < Hippuric acid . Cystin . Xanthin . Perspiration — Sudoric acid . ( Taurocholic acid Liver . . . ( Grlycocholic acid 'v Cholesterin / Leucin . Tyrosin . I Lactic acid ( Creatin . Creatinin ' Inosite . I Inosic acid I Sarcosin . Sarcin (Hypozanthinj -Ossein. Pancreas Muscles Osseous tiss 0H 4 N 2 O C 5 H 4 N 4 3 C 9 H Q N 4 3 c 3 h;xso 2 C 5 H 4 N 4 2 C 10 H s O l5 X? C O6 H 4 ,X0 7 S C 96 H 43 N0 6 C^H^O + HaO C 6 H 13 N0 2 C 9 H n N0 3 C 3 H 6 3 C 4 H 9 N 3 2 C 4 H 7 X 3 C 6 H r A + 2H,0 C 5 H 8 N 2 6 ? C 3 H 7 N0 2 CLH 4 N 4 sue- glucose in the liver. 323 Transformation of Amylaceous or Farinaceous Food. — Starchy matters are only found in small quantities in the tissues of the body — a fact which is quite natural as regards carnivorous animals, but very surprising in the case of herbivorous animals; and which seems to prove that starch is the chief respiratory aliment, and that it is very easily oxidized or burned. The greater part of the starch is transformed into carbon dioxide and water. Another portion is con- verted into fat, and the rest (a minute fraction) is fixed in certain tissues. Glucose in the Liver. — The existence of amyla- ceous matter in animal tissue is connected with a remarkable discovery made in 1849 by the illustrious physiologist, Claude Bernard — a discovery which we shall now describe, as well as the researches which led to it. If a carnivorous animal be subjected to prolonged fasting, sugar will be found in the hepatic tissue. The proportion of sugar found in the liver of carnivorous animals, or of animals fed exclusively with meat, is substantially the same as that in the liver of herbivorous animals, or of animals fed with amylaceous or saccha- rine food. Hence the production of sugar does not depend upon the existence of amylaceous and saccha- rine substances in the food. Objections might be raised to such experiments, on the grounds that the blood, in passing through the liver, might leave sugar behind it in this organ, and that sugar is merely retained and accumulated by the liver. 324 ANIMAL CHEMISTRY. Bernard responds to these suppositions by an experi- ment as interesting as it is conclusive. If a dog is killed and the liver removed, and, after washing this organ in such a manner as that all the su^ar shall be dissolved, it is allowed to remain exposed to the air for a day, it is found to again contain a very large proportion of sugar. If, also, the blood of the vena porta be analyzed before it reaches the liver, as well as after leaving this organ in the superior hepatic veins, a considerable increase in the amount of sugar is observed. In order to extract the sugar of the liver, the latter is cut into very small pieces and treated with boiling or even with cold water till nothing more is dissolved. The liquid is decoloured with animal charcoal, and evaporated over a water bath almost to dryness, and the residue treated with alcohol. The alcoholic solution furnishes glucose on evaporation. Bernard found 23.27 gr. of sugar in the liver, weigh- ing 1,300 grammes, of a hanged criminal of forty-three years, and 25.70 grammes in that of another, aged twenty-two, and whose liver weighed 1,200 grammes. Glycogene. — Sugar is produced in the hepatic tissues by means of a third substance — a sort of animal starch, designated glycogene — which has also been found on the internal surface of the amniotic membrane of ruminants, between the maternal and foetal placenta of rodents, in the muscles, and in the lungs of the foetus, and later in the liver ; also in different parts of the Crustacea and articulates. GLUCOSE IN THE LITER. 325 To prepare glycogene, the liver of a dog recently killed is cut into very small pieces and thrown into boiling water to precipitate and destroy the ferment which would otherwise change the starch into sugar. The fragments are now withdrawn, triturated with animal charcoal, and the pulp obtained boiled for about twelve minutes with five times its weight of water, filtered, and the residue treated with additional water. A liquid is obtained, from which the glycogene may be precipitated by alcohol. Glycogene is a white powder, soluble in water, which it renders milky, and insoluble in alcohol. The solution turns the plane of polarization strongly to the right. It has the composition of starch, x (C 6 H 10 O 5 ), is coloured violet-red by iodine, is converted into pyroxam by fuming nitric acid, and furnishes dextrine and glucose under the same circumstances as vegetable starch. The transformation of glycogene into sugar is effected by means of a ferment »analogous to diastase, which is found in fresh liver and even in the blood. According to Pavy, the proportion of glycogene in the liver varies with the nutrition ; it is large if the food is vegetable, and is, on the contrary, small if the food is animal. Amount of Glycogene in the Liver. Dog fed with amylaceous food. 17.23 per cent. „ „ „ meat. . . 6.97 „ ? , „ „ „ mixed with sugar .... ltL50 „ 326 ANIMAL CHEMISTRY. Bouget arrived at analogous results. On the other hand, Sanson has announced that on giving animals very farinaceous food, dextrin is found in the hlood and even in the muscles ; consequently muscles sup- plied as food would furnish amylaceous matters directly. There also exists in the muscles a saccharine substance called inosite, C 6 H 12 6 , and lactic acid ; consequently a diet of meat forms in the body amylaceous products. Amylaceous matter is also found in the muscles of new-born mammalia, and in the muscles of an organ when in absolute repose for a certain time. This all leads to the belief that there is an amylaceous matter which takes part in the formation of muscular tissues, but which disappears under ordinary circumstances, and is transformed into inosite and lactic acid. From these facts, and the existence of glycogene in other parts of the body than the liver, it follows that the liver is not absolutely the only organ having the property of transforming starch into sugar, but that it possesses it in a much greater degree than do the others. The sugar thus formed in the liver then passes into the blood, and there disappears, under normal condi- tions, being burned by the oxygen ; but certain natural or artificial conditions may diminish or increase the formation of this sugar. If the spinal cord be dissevered below the phrenic nerves, the circulation becomes weaker in the abdominal region, the temperature is lowered, and sugar is no longer found in the hepatic veins. GLUCOSE IN THE URINE. 327 ARTIFICIAL AND NATURAL DIABETES. It is observed that the amount of sugar increases in the blood of the superior hepatic veins when the pneunio- gastric nerves are irritated, when a special point in the wall of the fourth ventricle is pricked, when essence of turpentine, ether, or chloroform is in- jected into the vena porta, or simply when large proportions of these agents are inhaled, or, finally, when poisoning is produced by curarina, strychnia, or brucia. Let us follow step by step the research of Bouchardat, in order to study the theory of natural diabetes. And first we will recall the fact, that the digestion of amylaceous substances takes place in the intestines under the action of the pancreatic and intestinal juices, that the greater part of the starch is only changed into dextrine in the intestine, and that the further transformation of this dextrine takes place chiefly in the blood, under the action of the intestinal diastase absorbed simultaneously with the dextrine. Whenever there is an excess of glucose in the blood, this sugar passes into the urine. This fact may be demonstrated by injecting glucose into the veins : if there is but little, none is found in the urine ; if there is a large amount present, reagents will indicate its presence in the urinary secretion. The causes which produce an excess of glucose in the blood may be of two opposite characters : either the sugar is due to too great a secretion, or it may result 328 ANIMAL CHEMISTRY. from an insufficient destruction ; but more often veri- table glycosuria characterized by a constant excess of sugar, is due to both of these causes combined. It has been demonstrated that the sugar passes into the urine whenever there is more than 3 to 5 grammes in the blood at one time. There may be an incompleteness in the destruction of the glucose in the blood, either because the oxygen is not present in sufficient quantity or because it meets with substances which are more easily oxidized. Diabetes will result when, the nutrition being very starchy, there is an excessive transformation of amyla- ceous substance into glucose in the digestive canal. In fact the glucose is observed to increase with the propor- tion of amylaceous food. In persons affected with glycosuria the transformation takes place in the stomach, and this fact consequently explains why all albuminoid' substances are susceptible of acting upon starch ; they differ only in the rapidity of their action. It has also been shown that if the pancreas of a pigeon be removed it will still be able to digest amylaceous substances. Bouchardat has also observed that the stomach of persons having glycosuria is generally very much en- larged, and that persons who have a tendency to diabetes prefer farinaceous food, that they eat a great deal, and also that they eat rapidly, which circum- stances occasion a longer sojourn of the food in the stomach. When an organ is much used it acquires greater strength, and it is not unreasonable to admit that under these circumstances the gastric juice may TRANSFORMATION OF FATTY SUBSTANCES. 329 not be sensibly changed, and become incapable finally of dissolving amylaceous matter. Diabetes is accompanied by continual thirst ; hence it will be understood that since the food requires 8 to iO times its weight of water for digestion, the gastric juice must be insufficient if the digestion of the farinaceous food takes place in the stomach at the same time as the albuminoid. The sugar in the urine of diabetic persons ordinarily disappears on submitting them to a diet formed ex- clusively of meat, if the disease is not too advanced. In general, any cause on the other hand which pro- duces a diminution of the respiratory phenomena tends to retard the destruction of glucose in the blood and produce diabetes if the tissues are saturated with glycogenic matters. TRANSFORMATION OF FATTY SUBSTANCES. It has been established by a large number of experi- menters, who have operated upon different animals, that all of them not only assimilate fatty matters, but that they produce fat as well. Fat alone given as food pro- duces inanition. If animals be submitted to varied nutrition, there is much more assimilated fat found than there was in the food originally supplied them. Fatty bodies mixed with the other food facilitate growth. Amylaceous and saccharine substances are readily changed by digestion into fatty matters. It has not been demonstrated that nitrogenous foods are transformed into fats. 330 ANIMAL CHEMISTRY. The Role of Mineral Compounds in Nutrition is but little understood. Iron exists in different parts of the body, and principally in the blood globules. Sodium chloride is found in most animal fluids. It is thought, as we have already stated, that this substance is the origin of the hydrochloric acid of the gastric juice, and of the soda, which is found in the intestinal juices. It is known that this salt forms a compound with glucose (p. 186), also the existence of a compound of sodium chloride and urea has been shown ; and this is the reason for the belief that salt assists in the transformation and elimination of sugar and of urea. It aids in the solution of albumen and casein in certain humours. It prevents the dissolution of the blood globules, of the chyle and lymph, and we have reason to believe that it, like other salts elsewhere, is an important factor in the absorption of liquids by different membranes. Weiske and Wildt (7-1874-123) have made inves- tigations as to the action of food poor in lime and phosphoric acid, upon animals of rapid growth. They experimented upon three lambs about two and a-half months old, and in a healthy condition, feeding one with food poor in lime compounds, one with food poor in phosphoric acid, and the third with the usual kind of food; while the latter prospered and gained 13.5 pounds in fifty-five days, the first two lost thirteen and fourteen pounds in weight, and were by this time nearly dead. The animals having been killed, the com- position of their bones, as regards their inorganic con- stituents, were alike, but the amount of fat in the bones TRANSFORMATION OF FATTY SUBSTANCES. 331 of the- animal fed with normal food was greater than in both the others. A diet poor in calcium and phospho- rous compounds does not affect the constitution of the bones as regards their mineral constituents. Sodium Phosphate is capable of facilitating the absorp- tion of carbon dioxide by the blood, and consequently it is regarded as playing an important part in re- spiration. Calcium Phosphate is found in the majority of animal substances. This salt forms the greater part of the mineral matter of the bones, it exists in the ash of albuminoid compounds. It enters the body dissolved in water by means of carbonic acid. This substance, as well as the calcium carbonate, magnesium phosphate, and silica assist in giving solidity to the animal structure, and Chossat has asserted that the bones of pigeons completely deprived of calcium phosphate become so thin as to break. Magnesium phosphate cannot replace calcium phosphate. Weiske (36-'77) has investigated the influence of common salt upon the live- weight and the disassociation of nitrogen in various animals, and ascertained : that if the amount of salt in the food increases, and the animal be allowed all the water it desires, the amount of water consumed increases ; that with the increase of salt in the food and the consumption of water, as far as an increase in the production of urine accompanies the same, the disassociation of nitrogen increases ; that when the salt is removed, the consumption of water, as well as the production of urine, and disassociation of 332 ANIMAL CHEMISTRY. nitrogen, decreases; nevertheless the latter remains higher for a longer time than if a large ingestion of salt had not taken place. The increase in weight following a diet composed largely of salt is not due to increase in the amount of flesh, but to the accumulation of water in the body. Salt given in the food increases the desire for eatirig, but a notable increase or decrease in the digestibility of the food has not been proven. URINE. 333 UBINE. Human urine in its normal state is a liquid of an amber colour, the concentration of which, and conse- quently the density, varies with the age, sex, and state of digestion. This secretion is much more abundant, relatively, in infants than in grown persons, but the urine of infants is also richer in water, paler and less dense than that of adults. Parrot and A. Robin have lately (9-82-104) studied the urine of newly -born infants, and find that the secretion amounts to four times as much, referred to the weight of the body, as in adults. The quantity of urine in woman is to that in man nearly in the proportion of 13 to 12. The urine of man is pale, and charged with water after abundant ingestions of this liquid. Normal urine is that obtained soon after rising, its density is about 1.018, it varies between 1.012 and 1.022; its density may fall as low as 1.003, and rise to 1.030 after a hearty repast ; it is then yellow. Water is evacuated from five to six hours after having been taken into the system. The proportion of urine is extremely variable ; * ,200 to 1,300 grammes H 334 ANIMAL CHEMISTRY. is about the mean in men in twenty-four hours ; 1,300 to 1,400 grammes in women. But this quantity may sometimes increase to 2,000 grammes, and descend to 900 grammes. The three principal causes which influence the amount of this secretion are : — 1st. The nature of the blood ; a very aqueous blood increases it. 2nd. The rapidity of circulation in the kidneys. 3rd. The activity of the pulmonary and cutaneous respiration. The urinary secretion varies in inverse proportion to the respiratory phenomena; thus the quantity of urine emitted is greater in winter than in summer, in cold countries than in warm countries. After a cold bath the urinary secretion attains its maximum. Certain salts — nitre, for example — increases the quantity of urine ; they are denominated diuretics. Other substances retard and diminish this secretion, as cantharides, etc. The proportion of solids extracted from the body by the urine may vary from 40 to 80 grammes in twenty- four hours. Composition of Normal Urine of Man. Water. . . 936.76 931.42 932.41 Solid constituents. 63.24 68.58 67.59 1000 00 1000.(0 10(0.00 INFLUENCE OF FOOD ON THE URINE. 335 The solids are composed of — Urea . . 31.45 32.91 32.90 Uric acid . 1.02 1.07 1.07 Lactic acid . . 1.49 1.55 1.51 Aqueous extract . 1.62 0.59 0.63 Alcoholic extract 10.06 9.81 10.87 Lactate of ammo- nium 1.89 1.96 1.73 Chloride of sodium L and of ammo- nium 3.64 3.60 3.71 Alkaline sulphate? > 7.31 7.29 7.32 Sodium phosphate \ 3.76 3.66 3.98 Calcium and mag- nesium phos- phates 1.13 1.18 1.10 Mucus. . « 0.11 0.10 0.11 63.48 63.72 64.90 (Lehman.) INFLUENCE OF THE FOOD ON THE COMPOSITION OF THE URINE. Nature of the Food. Honey . . . . Animal . 4 . . Vegetable . . . Non-nitrogenous . Solids in 1000 parts. Urea. Lactic Uric Acid. Acid and Lactates. 67.82 87.44 59.24 41.68 32.498 53.198 22.481 14.408 1.183 1.478 1.021 0.735 2,725 2.167 2.669 5.276 Extractive Matters. 10.489 15.196 6.499 11.854 (Lehman.) 336 ANIMAL CHEMISTRY. Normal human urine is acid. This acidity is due to the action of the uric acid and other acids of the urine upon the alkaline phosphates. These acids deprive them of a portion of their alkali, and acid phosphates result. Uric or hippuric acid may also be found in excess in urine. The quantity of free acid evacuated in twenty-four hours represents 2. to 2.5 grammes of oxalic acid. The reaction of the urine depends upon the character of the food. In fact, this secretion is alkaline in herbi- vorous animals, since their food, which is very rich in carbon, forms bicarbonates with the bases which are in this secretion ; but the urine of an herbivorous animal may be rendered acid on submitting it to a diet of flesh food. The urine of herbivorous animals is turbid, and contains urea, hippuric acid, and a small quantity of phosphates ; it does not contain uric acid. Inversely the urine of carnivorous animals is acid and clear. It is rendered alkaline by forcing the animals to an exclusive vegetable diet. The urine of carnivora contains more urea and uric acid than that of man or herbivorous animals, while hippuric acid is wanting in it. Regarding the occur- rence of phenol, E. Bauman has recently observed that albumen and pancreas in putrefying form a certain quantity of phenol, and he believes in this reaction can be found an explanation of the existence of phenylsul- phates in the urine of dogs fed exclusively with meat (60-77-685). Violent exercise, fatigue, and excesses render human AMMONIACAL URINE. 337 urine alkaline. This fact is due to the combustion which, under these circumstances, transforms the uric acid into urea, and this body does not possess, like uric acid, the property of removing from the phosphates a portion of the alkali which they contain. Gosselin and A. Robin (9-78-72) have made experi- ments upon animals, injecting ammoniacal urine sub- cutaneously, and found that animals subjected to this treatment became feverish, and when larger quantities were injected they died. Thus in diseases of the bladder, the ammoniacal urine, if reabsorbed, must be deleterious, hence it would be advantageous to the patient that the amount of ammonium carbonate in the urine be reduced ; this, according to investigations of Gosselin and Robin, is effected by the administration of benzoic acid. Pasteur (9-78-46) claims that the ammoniacal nature of urine is due to the action of a ferment which obtains entrance through the urinary passages, or sometimes is introduced mechanically by means of chirurgical instruments. He recommends, therefore, that the instruments before being used be plunged into boiling water, or heated, then quickly cooled, and at once employed. A, Lailler (9-78-361) is of the opinion that the ammoniacal fermentation of urine depends in a great measure on the amount of mucus it contains. Gubler (9-78-1054) asserts that the decomposition of urea into ammonium carbonate, as is the case in the bladder in certain diseases of this organ, is due to small pus-corpuscles (neocytes). 338 ANIMAL CHEMISTRY. W. Zuelzer (60-1875-1670) has lately found that after a diet composed wholly of meat, the urine of a dog contained for every 100 parts by weight of nitrogen, 12 to 14 of phosphoric acid ; when fed with potatoes and bread, it contained 20 to 30 of phosphoric acid to 100 of nitrogen. In a healthy man, 20 to 25 years of age, the food being mixed and sufficient, the urine contains 17 to 19 of phosphoric acid to 100 of nitrogen ; with a diet of meat the proportion of phosphoric acid decreases, with a vegetable diet it increases. The time of day and the state of health have great influence upon the relative proportion of these two substances. Under normal conditions a man eliminates 12 to 14 of sul- phuric acid, 0.3 to 0.7 of lime, and 0.6 to 1.0 of magnesia to 100 of nitrogen . The urine, on leaving the body, deposits mucus after a certain time ; it often also deposits urates, especially during fevers. But its acidity soon increases, in consequence of the formation of more uric acid ; this acid is often seen to deposit in the form of rhomboidal prisms. Other acids are also formed, chiefly acetic and lactic acids. At the end of a few days the urine loses its acidity and becomes decidedly alkaline from the formation of a considerable quantity of ammonium carbonate. This salt is formed from the urea thus : — CO" \ CO" ) n2 H 2 N+2H 2 0=2(NH 4 ) j U H 2 ) This transformation of urea is favoured by the NORMAL CONSTITUENTS OF THE URiNE. &39 presence of the mucous sediment which urine deposits when exposed to the air, also by the action of beer, yeast, and albuminoid substances. It is a true fermentation, accompanied by the development of an organized vegetable substanee (Torulacece), which reproduces itself by germination. Often its action is impeded by the formation of infusoria, which maintain the acidity of the urine for a long period. Cohn finds the organisms to be Micrococus ureae. NORMAL CONSTITUENTS OF THE URINE. Of the solid constituents, urea is the most abundant. The urinary secretion in man furnishes about 30 grammes of urea in 24 hours, but this quantity may vary greatly. The average in women is 20 grammes ; it falls to 9 grammes in old men. A very nitrogenous diet increases it, while food which is poor in nitrogen diminishes it. Urea does not even disappear in an animal rigorously kept without food ; it is then formed at the expense of the tissues. When the urinary secretion increases, even though from the drinking of large quantities of water, the amount of urea produced also increases. It augments likewise, according to some authorities, during severe physical labour. We may admit, in general, that urea diminishes when the circulation of blood is sluggish, and that it increases when the circulation becomes active. There is only a very small quantity of urea in the 340 # ANIMAL CHEMISTRY. blood; it becomes greater when the kidneys perform their functions badly. Urea is not formed in the kidneys. Dumas and Prevost showed in 1823 that the blood of animals, from which these organs have been removed, contains considerable amounts of urea. This fact has been confirmed by Bernard and Barreswil, who also showed that, after the removal of the kidneys, the gastric and intestinal secretions increase. The gastric juice remains acid but contains ammonia. When the animal becomes entirely ex- hausted, urea is found in the blood in a very notable quantity. Picart and Meissner have obtained the same results, which have, however, been doubted by Oppler, Perls, and Zalesky. The question has been taken up by Grehant, who conceived the idea of determining the amount of urea with the greatest care, and he has perfectly demonstrated that urea accumulates in the blood in consequence of nephrotomy. 100 grammes of arterial blood contained : Urea. Before nephrotomy . . .0.088 grammes. Three hours and forty minutes later 0.093 „ Twenty-one hours later . . 0.252 „ Twenty-seven hours later . . 0.276 „ The urea increases, therefore, after the operation, and the increase takes place in a continuous manner proportional to the time. URIC ACQ). 341 The ligature of the ureters renders the kidneys totally inactive, for the blood which leaves this organ is found to contain the same quantity of urea as on entering. Hence, after the ligature of the ureters, following nephrotomy, urea accumulates in the blood. The amount of urea excreted by man represents very nearly the whole amount of nitrogenous food which has failed to be assimilated, for the surplus is obviously found in the excrements, and they contain very little. The urine, therefore, is the liquid through which the nitrogen is eliminated, and the urea is almost the sole agent for effecting this. For this reason the determination of the urea is highly important as furnishing us with data relative to the elimination of the nitrogen from the body. Urea is not produced in the muscles ; though creatin is easily transformed into urea when out of the body, yet, in spite of the considerable quantity of creatin which exists in the muscles, no urea is found in muscular tissue. On the contrary, it is sufficient to take in the food, creatin, gelatin, or analogous matters, to observe that the urea is thereby formed in greater quantity in the urine. It is therefore rational to admit that these substances are oxidized in the blood, and that their nitrogen is eliminated in the form of urea. Uric Acid. — The urinary secretion furnishes each day 1.183 grammes of uric acid on an average (Wundt). It increases during digestion, and diminishes when the body is fatigued. In general it is produced whenever oxidation is impeded, and an increase in uric acid is 342 ANIMAL CHEMISTRY. associated with a corresponding diminution of urea. This acid is found in the urine of persons affected with the gout. Uric acid, urate of ammonia, and urate of sodium are often deposited in urine a few hours after emission. Hipp uric Acid is found in small quantity in human urine. It increases with vegetable nourishment, in diabetes, and in certain other diseases. It is formed, molecule for molecule, when a benzoic compound is taken into the stomach. Lactic acid is only produced in the urine when digestion and respiration are im- paired. It is formed in fevers, and whenever digestion and circulation are impeded. Creatinin, and possibly creatin, exists in the urine. An adult throws off, in the urinary secretion, about 1.16 gr. of creatinin in twenty-four hours. J. Munk (60-'76-1799) finds over *008 per cent, sulphocyan- hydric acid in normal urine. Stoedler considers phenic acid and two ill- defined acids — damolic and damaluric acids, — to which the odour of the urine is supposed to be due, as constant constituents of the urine. Scherer regards xanthin as existing normally in the urine, though only in traces. It is an amorphous substance, soluble in acids and boiling water. According to Schunck, urine contains always indican. This name is given to a body not as yet obtained in a crystalline condition, soluble in water, alcohol, and ether, and is essentially characterized by its property of decomposing in presence of strong hydrochloric acid, INDIGOGEN. 343 furnishing, by combining with water, indigo and a saccharine matter, indiglucin. C ? ^^ w +2H 2 0=CANO+SO £ H ! A Indican Indigo Indiglucin The formation of this body accounts for the violet and reddish tints which are sometimes observed in urine undergoing decomposition. These phenomena take place only in the presence of atmospheric or other oxygen, as the indigo blue is very easily reduced. 2C 8 H fi NO+H 2 =C 16 H 12 N0 2 Urozanthin and still more appropriately indigogen are modern synonyms for indican. The substance which imparts to urine its yellow colour has been called urochrome by Thudicum. According to Heller, ether extracts from urine, which has been evaporated almost to dryness, a matter which he was not able to isolate, and which he calls uroxanthin. It is remarkable from the fact that, under the action of acids and in certain pathological states, it is transformed by oxidation into two other substances — one blue uroglaucin, the other red urrhodin. Since these substances have not been isolated with certainty, we shall not further dwell on them. Gtlucose.— Glucose is always present in normal urine, according to some chemists, though doubted by Seegen and Grorup-Besanez. The quantity of sugar present in normal urine amounts in twenty-four hours to 1 to 1.5 grammes 344 AJS'IMAL CHEMISTRY. according to Briicke, also according to Bence Jones. It is therefore less than one-thousandth. FATTY BODIES, SALTS, AND GASES IN URINE. Fatty "bodies are found in the urine, but their proportion is very minute. The quantity of saline matter in the urine is con- siderable. It amounts to about 15 grammes in twenty- four hours. This quantity may increase to 25 grammes, and decrease to 8 grammes. It is less in women, and still less in children. Among these solid matters ere prominently phosphates, sodium phosphate, calcium phosphate, and magnesium phosphate. The quantity of phosphoric acid eliminated in the urine varies from 3 grammes to 5 grammes in twenty-four hours. This acid increases during digestion. It diminishes in preg- nant women, and in the eighth month there is so little that both its reactions and those of calcium are hardly perceptible. Urine always contains alkaline chlorides, and chiefly sodium chloride. The quantity increases as the amount ingested increases, but the whole of this substance is not eliminated through the urine. The proportion of chloride increases after eating, and is at its' minimum during the night. Exercise increases the amount. The weight of chlorine evacuated in twenty- four hours is about 10 grammes. When all salt is removed from the food the amount diminishes in the mine, and remains fixed at 2 to 3 grammes per day, FATTY BODIES, SALTS, AND GASES IN URINE. 345 which amount is derived from the tissues, and a rapid enfeeblement results. Sulphates are found in the urinary secretion. The quantity increases daring digestion ; it averages 2 grammes in twenty-four hoars. Normal acid urine contains no ammonium salts, bat contains them on becoming alkaline, some time after its voidance. The same is the case with the urine of herbivora, which is always alkaline. Many substances taken into the body which do not serve as aliments are found again in the urine, in case they are not capable of uniting with certain principles of the body to form insoluble compounds. Those metallic salts are among these latter, which form precipitates with albuminoid substances. Substances not precipitable in the organism and difficultly oxidized — such a& chlorides, iodides, sul- phates, nitrates, urea, quinine, and most fragrant and colouring matters — reappear unchanged in the urine. Oxidizable substances, on the contrary, undergo the same transformations which they sustain when acted upon by oxidizing agents. Alkaline sulphides are converted into sulphates, alkaline organic salts into carbonates, benzoic and cinnamic acids into hippuric acid, uric acid into urea, salicine into s;:ligenin and salicylic acid. The oxidation of certain other matters is more complete ; they furnish carbon dioxide and water, which are the ultimate products of the oxidation of organic bodies. This is probably also what occurs to many substances which never reappear in the urinary secretion, even after abundant ingestion of the same ; 346 ANIMAL CHEMISTRY. such are niannite, ether, resins, the colouring matter of leaves, litmus, cochineal, amygdaline> anilin, camphor, etc. The rapidity with which these bodies pass into the urine depends upon their solubility. Potassium iodide is found in the urine in a few minutes after being administered. A longer time is necessary for the urine to assume the odour which is developed after eating asparagus and the inhaling of the vapours of turpentine. The gases of the urine are oxygen, nitrogen, and carbon dioxide. A mean of fifteen experiments made by Moring gave for a litre of fresh urine — Oxygen . . . - .0.65 c.c. Nitrogen 7.77 „ Carbon dioxide . . . . 15.96 „ These figures are probably too small, as the method by which the gases were determined was that of Magnus. Walking increases the amount of carbon dioxide. Carbon dioxide. Nitrogen. Oxygen. Urine during repose . 11.877 7.494 0.493 „ when walking . 22.880 8.204 0.466 The renal secretion of ophidians is solid, and com- posed chiefly of uric acid ; that of batrachians is liquid, and contains urea. The urine and excrements of birds contain chiefly acid urates, earthy phosphates, and a small amount of urea. ANALYSES OF DIABETIC URINE. 347 Pathological States. — The urinary secretion in- creases in certain diseases (diabetes, polydipsia). In the first case its density may increase, as sugar is often present in large proportions ; it sometimes is as high as 1.040. In polydipsia the density falls to 1.001. It diminishes in cholera, in diseases of the liver, and in fevers. Diabetes. — The quantity of sugar excreted in the urine may amount to 1200 to 1500 grammes in 24 hours. Bouchardat, to whom we are indebted for important investigations relative to this disease, has shown that the formation of sugar may be lessened or even arrested by submitting the patient to a nourishment devoid of farinaceous and saccharine matter, by furnishing him for example, instead of ordinary bread, bread made of gluten or flour freed from starch by washing. The uric acid diminishes in quantity, or disappears in the urine of diabetic persons. ANALYSES OF DIABETIC URINE BY SIMON AND BOUCHARDAT. Simon. Bouchardat. l"^~"lL I. Density . . 1.018 1.016 Water . . 957.00 960.00 837.58 Solid constituents 43.00 40.00 162.42 Urea . . traces. 7.99 8.27 348 ANIMAL CHEMISTRY. Simon. Uric acid . Sugar Alcoholic extract \ Aqueous extract > Salts . . ) Phosphates and mucus . Albumen . Oxide of iron I. traces. 39.80 2.10 II. traces. 25.00 6.50 Bouehardat. I. traces. 134 42 5.27 0.52 0.80 0.24 traces. traces, traces. traces. traces. 0.14 Markownikoff (72-182-362) finds acetone and ethyl alcohol, and believes they are formed from the glucose by fermentation. Claude Bernard has shown that diabetes can be produced artificially by puncturing the " fourth ventricle." A slow poisoning of frogs with curari, the slow action of strychnia, the destruction of the spinal colurnu of frogs, etc., produce diabetes, Artificial diabetes is dependent upon the liver, as this state can never be obtained in a frog from which the liver has been removed. Sa'ikowsky has shown that if the for- mation of glycogenous matter in the liver of a rabbit be arrested, a result which is easily produced by the action of arsenates, this animal cannot become diabetic neither by curari nor by puncturing the fourth ventricle. F. W. Pavy (112-23-59; 24-51) obtains diabetes OTHER ABNORMAL STATES OF THE URINE. 349 artificially in dogs by passing defibrir ated arterial blood through the liver ; saliva used instead of blood produced no glycosuria. Upon inhalation of oxygen Pavy noticed a like appearance of sugar in the urine. Albuminuria. — Albumen does not exist normally in the urine. When it is found, it is due either to the secretion of an albuminous urine by the kidneys, or to an admixture of blood, pus, or lymph. Albuminous urine is pale, acid, opaline, often of a density less than normal. As much as 20, 30 and even 35 grammes have been found to have been secreted in twenty-four hours. The albumen increases after taking food ; it is at its minimum during the night. It increases with nitro- genous food. According to Lehman this albumen exists in two states, one part is the modification of albumen called metaglobuline and paraglobuline, and is precipitable by carbon dioxide. The other remains in the liquid after the passage of the gas, and is precipitated by ordinary acids. Anosmia. — The urine is pale and scarcely acid in anaemic persons ; it sometimes even becomes alkaline. It is rich in salts and poor in most organic con- stituents. Other Abnormal States of the Urine. — The urinary secretion decreases considerably in fevers, and is of a deeper colour and more dense than normal urine. Its acidity increases on account of the uric acid which forms abundantly, and of the lactic acid which is also 350 ANIMAL CHEMISTRY. developed. The urea disappears in about the inverse proportion. The extractive matters increase ; the salts, and especially the sodium chloride, decrease. The proportion of urea increases in intermittent fevers, also at the commencement of typhoid fever. The quantity of urea, and especially that of uric acid, increases in inflammatory diseases. At the com- mencement of acute attacks the urea has been observed to amount to 60 grammes. The urine of persons affected with phthisis is richer in uric acid than normal urine, and fatty substances are also observed in it. The urea diminishes in nervous affections. In scarlatina and small-pox the urine contains am- monia, although it retains its acid reaction. A. Pohl found cholesterin (40-76-737) in the urine of an epileptic patient who had taken large doses of potassium bromide. Epithelial cells are found in large quantities m the urine in erysipelas, in scarlatina, in the commencement of Bright's disease, and in different urinary affec- tions. Fibrin and blood-globules appear in the urine during inflammation of the genital and urinary organs. In catarrh and in paralysis of the bladder the urinary secretion contains urate of ammonium. The urine is decomposed in the body of persons affected with catarrh of the bladder ; and in the urine are observed monads, vibrions, and mycoderms. Mucus is present in small quantity in normal urine. In various diseases of the genito-urinal organs, the OTHER ABNORMAL STATES OF THE URINE. 351 mucus increases to such an extent as to render the urine turbid or milky. Pus is found in the urine when suppuration is esta- blished in the genito -urinal tract. The urine in jaundice contains the acids and colour- ing matters of the bile. These acids also pass into the urine in pneumonia. The bile itself is often found in the urine, and in this case boiling ether agitated with the urine takes on a green colour. The urinarj secretion diminishes or ceases entirely in cholera. The proportion of phosphates increases in nervous ' affections. The quantity of chlorine decreases chiefly in pneumonia, in obstinate diarrhoea, and during cholera. Chyle and casein are found in certain urines. The urine is brown in acute rheumatism ; it is red in many diseases in which the colouring matter of the blood passes into the urine ; it is almost colourless in megrim and in nervous affections. Von Merling and Musculus (60-1875-662) have examined the urine of a person who for a long time took 5 to 6 grammes of chloral hydrate every evening. The urine had an acid reaction, reduced alkaline copper solutions, contained neither chloroform, formic acid, nor sugar, but it contained chloral hydrate in small quantity, and turned the plane of polarization to the left ; this latter property was due to an acid which they called urochloral acid, obtained by evaporating the urine acidified with sulphuric acid, and extracting the acid with a mixture of alcohol and ether. This new acid 352 ANIMAL CHEMISTRY. crystallizes in colourless silken needles, dissolves in water, alcohol, and a mixture of alcohol and ether, but is insoluble in pure ether ; with potassium, sodium, barium, and copper it gives well crystallized salts ; its composition is expressed by the formula 7 H 12 C] 2 6 . F. Baumstark (60-1874-1170) found in the urine of a person suffering with leprosy two peculiar colouring principles which he calls urorubrohrmatin and uro- Juchzohe matin. Urorubrohematin is a light bluish-black mass, insoluble in water, alcohol, ether, chloroform, or a solution of salt, soluble in alkalies, ammonium hydrate, alkaline phosphates and carbonates, alcohol containing acids, difficultly soluble in dilute sulphuric acid, and solutions of salt acidified with hydrochloric acid. The acid solution shows a characteristic absorp- tion spectrum. The formula obtained by analysis is C 68 H 94 N 8 Fe 2 26 (?). Urofuchsohematin is black, pitchy, insoluble in water, alcohol, ether, chloroform, acids, or acidified or non-acidified salt solutions ; it is soluble in alkalies, ammonium hydrate, alkaline phosphates and carbonates, and acidified alcohol. Analysis shows its formula to be C 68 H 10G N 8 O 26 (?). J. Miiller (60-1874-1526) found in the urine of a child pyromtechin. Urinary Sediments. — Human urine abandoned to itself often deposits solid crystalline bodies. During fever, urate of sodium is observed to form a short time after emission. These crystals are microscopic, and the appearance of the deposit is corpuscular and colourless. URINARY CALCULI. 353 They are recognized by their disappearance when the urine is heated. The urine sometimes deposits, three or four hours after emission, prismatic crystals of uric acid having a rhombic base. When ammoniacal fermentation takes place in urine, a deposit of urate of ammonium is observed mingled with calcium phosphate or carbonate and ammonio- magnesium phosphate. This sediment forms whitish opaque grains, insoluble in water, soluble in acetic acid, and insoluble in ammonia. At other times, crystals of calcium oxalate cvncl ammonio-magnesium phosphate separate out. C. Stein (1-187-99) finds in certain rare cases in which the urine is alkaline that magnesium phosphate occurs in the sediment. There also separates out from the urine, under unusual and not well understood circumstances, an organic matter called cystin, containing sulphur. This substance is colourless, insoluble in hot water, and soluble in ammonia. Besides these crystalline substances, the urine de- posits organized matters ; mucus is alway present in it, sometimes pus, spermatozoids, blood globules, and coagulated albumen. Urinary Calculi. — This name is given to concre- tions of solid substances which form in the bladder. At times they escape with the urine in small grains or powder ; they are then known as gravel. 354 ANIMAL CHEMISTRY. These deposits are formed of various substances : uric acid, urate of sodium or ammonium, calcium car- bonate, oxalate or phosphate, ammonio-magnesium phosphate, cystin or xanthic oxide. The cystin may be obtained by treating the calculi with sodium carbonate and adding acetic acid to the liquid, when it deposits cystin in handsome hexagonal plates. This substance may also be obtained from the kidneys. A cystin calculus is soluble in caustic alkalies, and even in solutions of alkaline carbonates, with the ex- ception of ammonium carbonate. It is dissolved by the mineral acids, and precipitated by acetic acid. Heated in the air, it furnishes sulphurous oxide. Heated with an alkali it furnishes a sulphide. The nature of the calculi formed of cystin will be described further on. ANALYSIS OF URINARY CALCULUS. Urate of sodium . 9.77 Calcium phosphate . . 34.74 Ammonio-magnesium phosphate 38.35 Calcium carbonate . 3.14 Magnesium carbonate . . 2.55 Albumen . • • 6.87 Water and loss . ° 4.58 • 100.00 (Lir Ldbergson.) ANALYSIS OF A CYSTIN CALCULUS. 355 ANALYSIS OF A FERRUGINOUS URINARY; CALCULUS. Ferric oxide . 38.81 Alumina . . 23.00 Silica . 17.25 Calcium . . '. . 8.02 Water . 10.89 Loss. . 2.03 100.00 (Boussiiigault.) ANALYSIS OF A CYSTIN CALCULUS. Cystin ..... Calcium phosphate and oxalate . . 97.5 . 2.5 100.0 (Lassaigne.) 356 ANIMAL CHEMISTRY. ANALYSIS OF HEINE. The whole of the urine voided during 24 hours is col- lected and its volume measured ; of this 250 grammes are taken and allowed to stand for 24 hours ; or the urine first voided in the morning after sleep is taken for analysis. We commence by determining by means of litmus paper the reaction of this urine, and then determine its density ; as the presence of water or albumen diminishes its density, while the presence of sugar and salts augments it. There are used for this test special areometers or hydrometers, called urinometers. It is well to verify once for all the graduation of these instruments by means of urines whose specific gravity has been determined by the ponder al method. G-LUCOSE. We have already stated that abnormal urine may contain very large proportions of sugar ; such urine is usually sweet and denser than ordinary urine. It is susceptible of fermentation, turns the plane of polariza- tion to the right, and is but slightly coloured. QUANTITATIVE ANALYSIS OF URINE. If it is desired to extract the sugar, basic lead acetate is added in excess, the solution filtered, the excess of lead precipitated by hydrogen sulphide, again filtered, and evaporated until it crystallizes. The Qualitative Tests.— Its presence merely may be detected by the tests given on page 187. It should, however, be remarked that these reactions are not reliable unless a precipitate appears within one or two minutes boiling, as secondary reactions are produced with the other substances contained in the urine. quantitative determination of the sugar by the reduction of copper salts. Preparation of the Liquid. — "Weigh out 200 gr. of pure Eochelle salt, which place in a flask graduated to 1 litre ; add 500 c.c. of a solution of sodium hydrate of 24° Baume (D = 1.199), or 600 c.c. of a solution 22° Baume (D =1.180). The solution is facilitated by agitating and slightly heating in a water bath. In another vessel dissolve 36.46 gr. of commercial copper sulphate, which has been purified by two or three recrystallizations, in 140 c.c. of distilled water, slightly heating. This solution is slowly poured into the first, stirring at the same time, that the precipitate may be dissolved. Binse out the vessel which con- tained the copper sulphate two or three times, and after 358 ANIMAL CHEMISTRY. placing the litre-flask in a vessel of cold, common water, add enough distilled water to bring the liquid in the flask up to 1 litre. This solution is very reliable, and may be preserved for months exposed to the light with- out alteration. For an improved reagent, see p. 187. Each 10 c.c corresponds to 0.050 gr. of pure cane sugar, or 0.0526 gr. of pure glucose. The determination is made by placing 20 c.c of the cupro-alkaline solution in a porcelain dish, bringing the same to boiling, and adding gradually — at the same time agitating with a glass rod — the saccharine urine from a burette graduated to tenths of a cubic centimetre. There is first formed a yellowish, then a red precipitate. "When the colour appears constant remove it from the flame ; the supernatant liquid soon becomes clear ; if it should appear greenish, again heat and add more of the urine drop by drop. The liquid must be neither greenish nor yellow. As long as there is any copper in the solution a drop of urine will produce an orange- coloured ring when it falls into the reagent. The amount of urine necessary to effect this will, of course, be an amount containing 2 x 0.0526 or 0.1052 gr. of glucose. Determination of Glucose in the Urine, by means of lead acetate. — In clinical experiments it is often sufficient to add to the urine a few drops of a con- centrated solution of lead acetate, separate the precipi- tate formed by filtering, and after bringing the filtrate to a known volume employ it in the same manner as the urine in the preceding operation. ANALYSIS OF URINE ALBUMEN. 359 The lead salt has the effect of precipitating the foreign matter. The glucose is not precipitated by the acetate unless ammonium hydrate is added. When diabetic urine is highly charged with sugar it must be diluted with 5, 10, or 20 times its volume of water. Glucose can also be determined by adding yeast to the urine, and from the loss of carbonic acid in the resulting fermentation calculating the glucose present. It can also be estimated by means of a polarizing appa- ratus, such as is used for determining the strength of saccharine solutions for sugar refineries. As it is not within the scope of this work to supply elaborate instructions with regard to urine analysis, those desiring full details regarding the examination of urine for this or other constituents should consult some author on chemical analysis, or specifically on the chemical examination of the urine. A liberal amount of laboratory work is requisite, however, for such as would acquire a practical acquaintance with the chemistry of abnormal urine. ALBUMEN. Albumen is coagulated by heat and nitric acid. It is necessary to have recourse to these two reactions to detect with certainty the presence of albumen in urine. In fact, by simply heating the urine it often becomes turbid, owing to the precipitation of the earthy phos- 360 ANIMAL CHEMISTRY. phates or carbonates; these salts may be recognized, however, by adding a drop or two of nitric acid, which will redissolve the precipitate formed. On the other hand, nitrj.c acid will produce a white precipitate m the nrine of a patient who has been taking various resinous remedies. When it has been found that four to five cubic cen- timetres of urine coagulates on heating, and that it continues to coagulate after adding eight to ten drops of nitric acid, we may conclude that this urine contains albumen. In order to estimate the amount of albumen we com- mence by ascertaining whether the urine is alkaline or not ; in case it is, it should be slightly acidulated with acetic acid. 100 c.c of the urine are taken and heated so as to cause coagulation — that is, until the urine just commences to boil. The liquid is then thrown upon a double filter, i.e., two filters of equal size and weight placed one within the other. The albumen remains upon the inner filter; it is washed with water, then with alcohol, and when it has well drained the two filters are dried at 110°. The difference between the weight of the filters with the precipitate and the filters empty is the weight of the albumen. Another determination to check the first may be made, precipitating the albumen with dilute nitric acid. DETERMINATION OF UREA BILE. 361 UREA. "We have already mentioned the importance of noting the variations in the amount of urea, since these varia- tions give us light upon certain points in the process of nutrition. In order to ascertain whether a given urine is very rich in urea, a few drops are placed on a watch- glass with an equal volume of nitric acid and the glass floated on cold water ; after a few minutes crystals of nitrate of urea are to be seen. In order to determine the amount of urea, Leconte's method may be employed, which is based upon the oxidation of the urea by hypochlorites : — CH 4 N 2 + SNaCIO = 3NaCl + C0 2 + 2H 2 + N 2 . Carbon dioxide and nitrogen are disengaged: the former is absorbed by a solution of sodium hydrate, and the latter collected and measured ; from the volume obtained the amount of urea can be determined. BILE. I. Gives with sub-acetate of lead a greenish-yellow precipitate. II. Gives with a drop of nitric acid, green, blue, yellow, violet, and red coloration. III. Gives with a solution of white of egg, on adding nitric acid, a precipitate which is bluish-green ; whereas in the absence of bile it is white. 362 ANIMAL CHEMISTRY. IY. Yields with tincture of iodine a green colora- tion. According to W. Gk Smith (7-[3] 8-299) this reac- tion distinguishes bile from the so-called indican. URIC ACID Is recognized qualitatively by the test given on page 125. It is usually determined quantitatively by adding to a given amount of urine — not less than 150 to 200 c.cm. — sufficient hydrochloric acid to fully precipitate the uric acid, and allowing the liquid to stand for twenty-four to thirty- six hours. Traces of uric acid still remain in solution which, however, according to Neubauer, are compensated for by the amount of the urine pigment which also falls with the uric acid. The precipitate is filtered off, washed, dried, and weighed. URATES. The urates of sodium and ammonium are among the constituents of normal urine ; they are often deposited after voidance when the urine has become cold ; a deposit is then observed which disappears on slightly heating. These urates may be recognized by charac- teristics which will be given under Urinary Deposits. INORGANIC SALTS IN URINE. 363 HIPPURIC ACID. If hippuric acid is found to exist in notable quan- tities in urine, it may be determined by the method already given under the general discussion of this acid. CREATININ. Creatinin may be detected and even quantitatively determined by the following method: Milk of lime, then calcium chloride, is added to 300 to 500 c.c. of urine until a precipitate no longer occurs ; after being allowed to stand for a few hours the solution is filtered and the filtrate evaporated in a water-bath to the con- sistency of a syrup ; 40 c.c. of 90 per cent, alcohol is then added, and the whole allowed to digest for twenty- four hours. The clear liquid is decanted off, and a solu- tion of zinc chloride, as nearly neutral as possible, is added. A compound of zinc chloride and creatinin is formed, which is collected on a filter, washed with quite cold water, and dried. INORGANIC SALTS. The amount of salts in urine may be determined by evaporating 5 to 10 grammes in a porcelain dish. The residue is ignited at a slightly elevated temperature and weighed. The chlorides, sulphates, phosphates, lime, etc., may be determined by the methods usually employed in inorganic quantitative analysis. 364 ANIMAL CHEMISTRY. TJEINAEY DEPOSITS. If the urine has produced a deposit, its nature may be determined by plunging one end of a glass tube, which has been drawn out to a point, down into the deposit, the other end being closed by the finger ; the finger is then removed, a quantity of the deposit allowed to run iuto the tube, the finger replaced, and tiie tube withdrawn. A certain quantity of the deposit is thus obtained, which may be tested with different reagents and examined under the microscope. Urine which contains an excess of uric acid is acid and limpid ; the deposit is then crystalline and slightly coloured, and is soluble in potassium or sodium hydrate, insoluble in ammonium hydrate or acetic acid. Nitric acid imparts a darker colour to urine rich in uric acid; a brown deposit may also be formed, which is soluble in alkalies. Urine containing urates becomes turbid shortly after voidance ; this deposit is white, or coloured and muddy. On heating it dissolves, as well as by adding potassium or sodium hydrate. Sometimes this deposit is coloured. Urine containing earthy phosphates may become turbid, but this deposit cannot be confounded with the preceding, as it does not dissolve on heating, is soluble in acetic acid, while not soluble in potassium or sodium hydrate. Urinary deposits formed of calcium oxalate are white; URINARY DEPOSITS. 365 they are insoluble in ammonium hydrate and acetic acid ; they also do not dissolve on heating, but are soluble in mineral acids. If the deposit were formed of calcium carbonate, it would dissolve in acetic acid with the disengagement of carbon dioxide. Deposits of ammonio-magnesium phosphate are white ; soluble in acetic acid, insoluble in ammonium hydrate. Urine containing cystin has an acrid and even repulsive odour. It furnishes a deposit which does not dissolve on heating, and is soluble in ammonium hydrate. Certain urines become turbid on account of the mucus they contain, or because decomposition has set in. The presence of blood renders the urine red, the presence of bile greenish. Urines are sometimes met with which are whitish or opalescent; agitation with ether renders them clear. Blue and blackish urines also occur. If a drop or two of a urinary deposit is viewed through a microscope magnifying 250 diameters, and the preceding reactions employed, they will appear much more distinct. We would, however, add the following : Uric acid occurs in crystalline plates of a diamond shape ; their angles are often rounded off. These plates are often isolated, sometimes united in the form of rosettes and stars, and rarely in the form of needles. The urates are sometimes amorphous, sometimes crystalline. Deposits of urates may be distinguished from those of uric acid by their solubility in hot 366 ANIMAL CHEMISTRY. water. They are generally found when the urine is alkaline. Crystals of urates, heated with a small quantity of nitric acid, give a residue of uric acid. More nitric acid forms alloxan, as do deposits of uric acid, and this yields a characteristic red colour with ammonium hydrate. Calcium phosphate is amorphous. Ammonio-magnesium phosphate occurs in prismatic crystals. Calcium oxalate crystallizes in regular octahedrons. Cystin, C 3 H 7 NS0 2 , occurs in beautiful hexagonal plates. It is obtained by treating the deposit with ammonium hydrate, and allowing the liquid to stand ; the cystin separates out, and by the aid of the micro- scope the form of the crystals may be distinctly seen. Under these conditions the uric acid would not dis- solve, a fact which permits of distinguishing between deposits of cystin and those of uric acid. Cystin is neutral, insoluble in water, alcohol, ether, or acetic acid. It is soluble in the mineral acids, also in oxalic acid. Ignited on platinum foil, it gives off an allia- ceous odour. It is coloured, like uric acid, upon treatment with nitric acid and ammonium hydrate. It dissolves in alkaline solutions. Heated with potas- sium or sodium hydrate in presence of lead oxide, it blackens on account of the formation of lead sulphide. Cystin is of rare occurrence, and its physiological and chemical relations have not been fully studied. Loebisch (1-182-231) has shown that no diminution URINARY CALCULI. 367 of urea or uric acid occurs in cases of cistinuria, though earlier investigators, and recently also Nieman (1-187-101), have come to the conclusion that uric acid at least decreases. Nieman established in the same research that there is no change in amount of sulphur in urine by reason of the presence of cystin. Pus may be recognized by the spherical globules, in which two or three nuclei are observed, on the addition of acetic acid. This matter is converted into a jelly- nke mass in contact with potassium or sodium hydrate. Mucus may be distinguished by its ropy consistency and its coagulation with acetic acid ; various kinds of cells are observed floating in the liquid. In these deposits epithelium cells are almost always found ; they are oval or irregular. We also find in urinary deposits : Blood Globules. — If the urine remains acid, they appear as quite characteristic discs ; if the urine becomes alkaline, they are destroyed. Tube Casts, — These may be: epithelial, fibrinous, mu- cous hyalin, (or colloid) and amyloid. The first have special diagnostic importance in diseases of the kidneys. These casts are generally nearly straight, though sometimes curvilinear, and not unfrequently are difficult to find. The epithelial cells which cover them are nearly normal in appearance. Epithelial Cells. — These may originate from the kidney, the bladder, the ureters, or the canal of the urethra. Vibrions. — Linear in form, and exhibiting character- istic movements. 368 ANIMAL CHEMISTRY. UEINAEY CALCULI. Physical Aspect. — 1. Uric Acid. — Form, round ; colour, brown or reddish ; fracture, earthy or partially crystalline. When sawn through, a powder is obtained resembling the sawdust of wood. 2. Urate of Ammonium. — These calculi are small, and of a clay or ash colour, with an earthy fracture. They are formed in concentric layers. 3. Cystin. — These calculi are voluminous, pale yellow, rounded in form, glossy, crystalline, and sometimes striated. 4. Cafcium Oxalate. — Calculi of this substance are called mulberry calculi, from their resemblance to the fruit of the mulberry-tree, their surface being covered with rounded tubercles. They are usually grey, though sometimes dark brown, which colour is due to the organic matter which covers them. Their fracture usually is granular, sometimes crystalline. 5. Ammonio-magnesium Phosphate. — These calculi are white, crystalline, semi-transparent, covered with small brilliant crystals ; they are very easily pulverized. 6. Calcium Phosphate. — These calculi are white, amorphous, and formed in concentric layers. The following table indicates in brief the method to be followed in examining different calculi. "We should mention , however, that calculi are not always composed of a single substance ; they are quite frequently formed of several compounds. This table of reactions applies as well to urinary deposits. CHEMICAL EXAMINATION. 369 370 ANIMAL CHEMISTRY. CUTANEOUS SECRETIONS OR TRANSPIRATIONS. We include under this head the products of the sebaceous follicles, of the glands of Meibomus, and the wax of the ears. These contain an albuminoid substance, of which but little is known, neutral fatty bodies (stearin, olein), epidermic cells, and epithelium and other cells, sodium chloride, ammonium chloride, and alkaline and earthy phosphates. SWEAT. The quantity of this secretion has not yet been determined. It is, however, known that it is quite large, and it is believed to be more than half of that of the pulmonary exhalations. It is obtained by pressing sponges against the skin while in perspiration, and afterwards washing these sponges with water. Sweat is an acid liquid, of an odour variable with individuals, and of a saline taste. It leaves 1 to 2.5 per cent, of fixed substances on evaporation at 100°. Sodium chloride, mixed with potassium chloride, forms two-thirds of this residue. Alkaline phosphates have not been found in it. Its acidity is due to acids of the fatty series ; the most abundant is formic acid associated with small quantities of acetic and lactic acids. Favre has detected in it the existence of a special acid — sudoric acid. Sweat contains fatty matters derived from the SPERMATIC FLUID, OR SEMEN. 371 sudorific and sebaceous glands arid a nitrogenous sub- stance (possibly urea), which, readily changes into am- nioniacal salts. In uraemia, the perspiration of the face contains a considerable quantity of this substance. The sweat appears milky, on account of the epithelial cells with which it is charged. It contains nitrogen and carbon dioxide gases. THE SPERMATIC FLUID, OR SEMEN, Is viscid, opaque, heavier than water, and possesses a marked odour. Heat does not coagulate it. It is precipitated by alcohol and acids. It is formed of a colourless fluid, in which float a large number of very minute bodies, called spermato- zoids. In man they have a flattened or oval body, to which is joined a long filiform " tail." The movements are principally executed by the tail, which has a sort of vibratile undulatory motion. The seminal liquid gelatinizes after emission. This effect is attributed to an albuminoid matter called spermatin, which is a substance resembling globulin and mucin. Heat does not coagulate its solutions. Acetic acid renders them turbid, and an excess of the acid re-dissolves the precipitate. These solutions are pre- cipitated by potassium ferrocyanide and nitric acid. After having been evaporated to dryness, this sub- stance no longer dissolves in water, but is dissolved in very dilute alkaline solutions. 372 ANIMAL CHEMISTRY. The fecundating property of the spermatic fluid rests in the spermatozoids. They preserve vitality for a long time in the urine, and even in a dry state. If a cloth impregnated with dry sperm be moistened and placed on the stage of a microscope, the active spermatozoids are readily perceived. Spots of semen heated slightly for a few minutes assume a dark yellow colour. The seminal liquid contains in suspension, besides the spermatozoids, white granular corpuscles, mucus, and debris of epithelium. It holds in solution, in addition to spermatin, lecithin, 'various fatty bodies, sodium carbonate — which renders it alkaline — sodium chloride, and phosphates. MTJCUS FLUIDS OF THE SEEOUS MEMBRANES. Mucus is a viscous, ropy liquid, containing epithelial cells and small colourless corpuscles, few in number in a normal state, but which increase greatly when the membranes are inflamed. The composition of mucus in different parts of the body presents differences not yet determined. Mucin is the name given to that principle of which, however, little is known, imparting to mucus its ropy consistency. It is found in a number of the fluids of the body. Eichwald has given a process by means of which he extracts this substance from different liquids or tissues. mucus. 373 It is most readily extracted from pulmonary expec- torations. These are diluted with water, and an excess of acetic acid added. The turbid liquid is washed on a filter with dilute acetic acid as long as the filtrate gives a precipitate with potassium ferrocyanide. The solutions are then treated with lime water and the mucin precipitated from the solution by acetic acid. This body appears to be largely soluble in water ; it is precipitable by alcohol and dilute acids, and soluble in alkalies. It is distinguished from albumen in not coagulating by heat. It also furnishes tyrosin under the action of dilute sulphuric acid. Gk Gaelchli (18-78-77) found that mucin on putre- fying generated indol, phenol, and a sugar-like substance. Normal mucus does not contain albumen. An analysis of nasal mucus by Nasse yielded : Water 933.7 Mucin 53.3 Lactates and extract soluble in alcohol 3.0 Extract soluble in water and phosphates 3.5 Alkaline chlorides . . . ' . 5.6 Sodium hydrate ..... 0.9 1000.0 374 ANIMAL CHEMISTRY. Urine left standing for a short time often deposits mucus which is whitish, soluble in the alkalies, and partially in acids. It facilitates the transformation of the urea present into ammonium carbonate. Serosity effects the lubrication of various surfaces of the body, preventing friction ; its composition varies slightly in different organs. Albumen, mucus, and soda are ordinarily found in it. Synovia is the serosity which lubricates the joints. It is dense and slightly alkaline. It differs from mucus in containing albumen. According to Berzelius, it contains : — Water 926 Albumen 64 Extractive matters and soluble salts 6 Calcium phosphate . . . 1.5 Its composition, however, varies according to amount of exercise taken. ANALYSIS OF THE HYDROCEPHALUS FLUID. Mucus with a trace of albumen 0.112 Sodium carbonate . 0.124 Sodium chloride 0.664 Potassium chloride and sulphate traces Calcium phosphate » ?> Magnesium phosphate . ► ;» Iron phosphate 0.020 "Water 99.080 100.000 (Marcet.) COLLOIDIN. 6 ANALYSIS OF THE HYDKOPSICAL FLUID. Albumen .... 2.38 Urea 0.42 Sodium chloride . 0.81 Sodium carbonate . 0.21 Sodium phosphate, with traces of sodium sulphate 0.06 Mucous substance . 0,89 Water 95.23 100.00 (Marchand.) 375 VESICULAR SEROSITY. Coagulable albumen . . . 5.25 Albumen more soluble in water . 0.50 Salts 0.26 Water 93.99 100.00 (Brandes and Reimanri.) Colloid in. — (rautier, Oazeneuve, and Daremberg (97-[2] 21-482) have examined the jelly-like contents of a large ovarian cyst : they diluted the same with water, heated to 110 degrees in closed vessels, filtered after allowing to cool, dialyzed the filtrate in order to remove the salts, and precipitated with alcohol, whereby they obtained a white flocculent mass, soluble in water, 376 ANIMAL CHEMISTRY. and not precipitated either by metallic salts or mineral acids, but precipitable by tannic acid and alcohol. They have called this substance colloidin, and give as its formula C 9 H 15 N0 6 . According to Grorup-Besanez this body is closely allied to mucin. Human milk Cows' ?> Goats' jj Asses' » Sheep's >> MILK Milk is a white, opaque liquid, inodorous while cold, and of a slightly sweetish taste. Its density, varies but little : — 1.0320 1.0300 1.0341 1.0355 1.0409 Human milk is alkaline. The milk of herbivora has generally the same reaction. That of carnivora is believed to be acid ; at least it acidifies so quickly when once drawn that it is difficult to state its reaction positively. Milk is formed of an almost colourless and trans- parent liquid, in which float an immense number oi oleaginous globules. These globules are visible only under the microscope; their size varies from 0.0027 m.m. to 0.0041 m.m. They are opaque, and it is to these globules that the opacity of the milk is due. The fatty bodies of which they are formed are probably MILK. 377 contained in an albuminoid membrane. If to milk we add a little potassium hydrate and ether, the alkali dissolves the membrane, the ether absorbs the fatty bodies, and the milk is changed into a limpid, transparent liquid. On placing some milk under a microscope, and moistening it with a drop of acetic acid, the membrane will be seen to be attacked, and the fatty bodies will immediately run together, while if it be simply agitated with ether, the globules remain unchanged. Robin, however, supposes that the milk globules have no special envelope, but are surrounded by a thin layer of a saponaceous matter formed of fatty bodies, salts, and albuminoid compounds. Milk left to itself separates into two layers ; that formed above, by the union of the globules, constitutes the cream, that below forms a white liquid, having a slightly blue tinge. On subjecting milk to a violent and prolonged beating, the globules unite and separate from the liquid, and butter is obtained. The fatty bodies of milk are formed of several principles: — Butyrin, caproin, caprin; about . . 2. Olein . 30. Margarin ...... 68. And a small amount of stearin. But these proportions are necessarily very variable. E. Tisserand (46- [3] 9-440) has summarized the following data :— 378 ANIMAL CHEMISTRY. I. The separation of cream occurs the more promptly according as the temperature approaches 0°. II. The lower the temperature the larger the volume of cream and the yield of butter ; at the same time the butter milk, butter, and cheese, are all of a better quality. In human milk the mean percentage of butter is 2.42. It ranges between 2.80 and 3.50 in cows' milk. According to different experimenters the margarin is very impure ; it contains stearin, myristin, and even other compounds. The lower layer contains various substances, of which the principal ones are : — Casein, an albuminoid matter previously described : the milk contains more of this substance after a nourishment of nitrogenous food than after one of vegetable matters. Sugar of milk Different salts, principally phosphates and chiefly calcium phosphate ; sulphates are not present. Milk allowed to stand in the air rapidly loses its alkaline reaction and becomes acid. It then coagulates. This effect is due to the lactic acid which forms spon- taneously in milk. It is formed by a fermentation called lactic fermentation. The sugar of milk is the substance which is trans- formed into lactic acid with the co-operation' of nitro- genous ferments. The coagulum is formed of casein and fatty sub- MILK. 379 stances the liquid which remains is known as butter milk. A. Yogel (75-23-505) confirms the observations of Schwalbe (36-1872-833) that oil of mustard pre- vents the coagulation of milk ; according to his investi- gations the formation of lactic acid is in a great measure hindered by the presence of the oil of mustard. Oil of bitter almonds and oil of cinnamon prevent the formation of this acid to a less degree, while oil of turpentine, oil of cloves, benzol, carbolic acid, carbon- bisulphide, and hydrogen sulphide are almost without action. It is an alkali, soda, which holds the casein in solution in fresh milk, and milk may be kept fresh for a very long time by simply adding to it a few thousandths of an alkaline bicarbonate. On the other hand, milk will at once coagulate on the addition of an acid. Besides the acids, a large number of substances possess the property of causing milk to coagulate ; such are alcohol, tannin, different salts, many plants which are not acid, the flowers of the artichoke, of the thistle, and of the butter wort (Pinguicula vulgaris), which render it ropy, and especially rennet, a substance obtained from the stomachs of sucking calves. One part of rennet will coagulate 30,000 parts of milk, and the wooden vessels which have contained rennet, and which are used in dairies, may be used for a very long time for the operation without any subsequent addition of this substance. According to certain experimenters 380 ANIMAL CHEMISTRY. rennet effects the transformation of a certain amount of the sugar of milk into acetic acid ; according to others this transformation is produced by an albuminoid sub- stance called chymosin. The coagulum of milk is employed in making cheese. The nature of the food influences the character and quantity of this secretion. The butter increases if the food contains much fatty matter and when the food is vegetable. A mixed or animal diet diminishes the proportion of butter, and increases the proportion of casein and sugar. Fasting diminishes the secretion. The milk is then poor in sugar and salts, and becomes rich in fat and casein. During certain affections of the mammillary glands, mucus, infusoria, fibrin, and epithelial dSbris are found in the milk. Albumen occurs in t\e> milk when the mammillary glands are the seat of inflammation. In Bright's disease urea passes into the milk. COMPOSITION OF MILK, BY BOTTSSINGAULT. Human. Cow. Ass. Goat. Mare. T>og. Water 88.4 2.5 4.8 3.8 87.4 4.0 5.0 3.6 90.5 1.4 6.4 1.7 82.0 4.5 4.5 9.0 89.63 traces 8.75 1.60 66.30 Butter 14.75 Sugar of milk and sol- uble salts 2.95 Casein, albumen, and insoluble salts 16.00 99.5 100.0 100.0 100.0 99.98 100.00 COMPOSITION OF MILK OF A WOMAN. 381 Mott (100-6-364) finds milk of the negro race richer in solid matter than that of the Caucasian. According to recent investigations of Lieberman (1-181-102) there is another albuminoid substance in milk besides those given in the foregoing table, but which has not yet been isolated. COMPOSITION OF THE MILK OF A WOMAN, AT DIFFERENT PERIODS, BY SIMON. Days after Child- birth. Specific Gravity. Water. Dry Residue. Casein. Sugar. Butter. Mineral Salts. 2 1.0320 82.80 17.20 4.00 7.00 5.00 0.316 10 1.0316 87.32 12.68 2.12 6.24 3 46 1.180 17 1.0300 88 38 11.62 1 96 6.76 3.14 0.166 18 1.03O0 89 90 10.10 2.57 5.23 1.80 0.200 24 1.0300 88.36 11.64 2.20 5.20 2.64 0.178 67 1.0340 89.32 10 68 4.30 4.50 1.40 0.274 74 1.0320 88.60 11.40 4.52 3.92 2.74 0.287 82 1.0345 9i.40 8.60 3.55 3.95 0.80 0.240 89 1.0330 88.06 11.94 3.70 4.54 3.40 0.250 96 1.0334 96.04 10.96 3.85 4.75 1.90 0.270 102 10320 90.20 9.80 3.90 4.90 80 0.208 109 1.0330 89 00 11.10 4.15 4.30 2.20 0.276 117 1.0344 89.10 10.90 4.20 4.40 2.00 0.268 132 1.0340 86.14 13'. 86 3.10 5.20 540 0.235 136 1.0320 87.36 12.64 4.00 4.00 3.70 0.270 According to Berzelius, skimmed cows' milk con- tains : — Casein, with a small quantity of butter 2.600 Sugar of milk .... 3.500 Alcoholic extract, lactic acid, lactates 0.600 Potassium chloride . . . 0.170 382 ANIMAL CHEMISTRY. Alkaline phosphate .... 0.025 Calcium phosphate, lime combined with casein, magnesia, and traces of iron oxide .... 0.230 Water 92.875 100.000 H. Eitthausen (18-77-348) has recently found in milk another carbohydrate, differing from milk sugar, and more resembling dextrin. FLESH. We can have only imperfect ideas in regard to the transformations which the plastic principles (albumen, fibrin, casein) undergo in being converted into assimi- lable matter and tissue, also as to the manner in which each organ selects from the nutritive substances the elements which are suited for its use. It is certain that albumen plays the principal rdle, for it is observed to give rise to fibrin and other nitro- genous substances under certain circumstances, and especially in the incubation of the egg ; certain physi- ologists have also thought that in digestion all nitro- genous substances are converted into albumen, and that in nutrition the albumen is changed into fibrin, a substance which, from the facility with which it coagu- lates, is the principal agent in the creation and renewal of the tissues, that is, of the solid portions of our bodies. MUSCULAR TISSUE. 383 These ideas are probably exaggerated, or at the least their correctness has not been demonstrated. Muscular Tissue. — The muscles are constituted of a reddish contractile tissue, formed of fusiform elon- gated cells and of striated filaments, constituting an external envelope, called the sarcolemma, and of inter- nal substances, from which a variety of fibrin, syntonin, may be extracted. This latter is probably the substance into which albuminoid matters are changed during digestion in the stomach (parapeptone). Solutions of syntonin in acids are not coagulated by boiling ; they are precipitated by chlorides and alkaline sulphates. Syntonin dissolves in caustic alkaline liquids and in dilute solutions of carbonates, and is reprecipi- tated when these solutions are neutralized, even in the presence of alkaline phosphates. This last character distinguishes it from the albuminates. The fibres of the muscles are surrounded hy a fluid which may be considered as the plasma of the muscles. It may be prepared according to Kiirme by removing the muscles of an animal recently killed, and freezing them at a temperature of about — 7°, whereby they become very brittle. They are pulverized in a well- cooled mortar, and thereupon subjected to a heavy pressure in an appropriate press. A liquid is thus obtained, which is placed upon a filter surrounded by a refrigerating mixture. The liquid, which filters very slowly, is opaline-yellowish, viscid, and alkaline. It coagulates at ordinary temperatures, furnishing 384 ANIMAL CHEMISTRY. myosin, which may be readily obtained by causing the filtrate to fall into water at the ordinary temperature. If acid solutions of myosin are saturated, it is then no longer this body which precipitates but syntonin. Syn- tonin differs from myosin by not dissolving in solutions containing less than 10 to 12 per cent, of common salt. Myosin may also be. obtained more simply by pounding flesh with water containing 8 to 9 per cent, of common salt. After allowing this to stand twenty-four hours it is filtered by being pressed through cloth, and the myosin precipitates on pouring the liquid into water. The liquid which remains after the coagulation of myosin contains, according to Kiihne, two albuminoid substances, one coagulable at 75°, the other at 45°, and alkaiine albuminates ; also salts, which are chiefly phosphates, lactic acid, and lactates ; sugar and various organic substances, as creatin, creatinin, inosic acid, inosite, sarcosin, sarkin, and xanthin. This liquid is coagulable by heat, and of a red colour ; its acidity is due to lactic acid and acid phosphate of potassium, which may be extracted from the muscles by dilate alcohol. It is claimed by Fremy and others that there exists in the muscles a special acid, called oleophosphoric acid, and that this acid is combined with sodium. According to Dubois Eeymond, the muscles do not possess an acid reaction until after death, and while contractile their reaction is slightly alkaline. In certain pathological states, urea, uric acid, and various other products are present. COMPOSITION OF FLESH. 385 H. Struve (60-'76-623) finds in fatty muscular tissue a new body which gives the absorption spectra of blood, but is changed, unlike the latter, by the action of alkaline sulphides and acids. COMPOSITION OF FLESH. Pectoral Muscles. Man. Woman "Water . 72.46 74.45 Muscular fibres, vessels, and nerves . 16.83 15.54 Fats .... 4.24 2.30 Extractive matters 2.80 3.71 Cellular tissue . 1.92 2.07 Soluble albumen 1.75 1.93 100.00 100.00 (Yon Bibra.) Flesh leaves from 2 to 8 per cent, of ash, formed chiefly of alkaline and earthy phosphates ; sodium chloride and sodium sulphate are also present, The brcth produced by digesting muscular tissue in water contains, according to Chevreul : — Water 988.57 Organic substances dried in a vacuum 12.70 Salts (phosphates, sulphates and chlo- rides of potassium, sodium, calcium, magnesium, and iron) . . . 3.23 1004.50 386 ANIMAL CHEMISTRY. Creatin, C 4 H 9 N 3 2 + H 2 0. Creatinin, C 4 H 7 N 3 0. Sarcosin, C 3 H 7 N0 2 . These three bodies have the highest importance in connection with the study of muscular tissue. Liebig found in : Muscular flesh of the ox . 0.69 creatin. „ horse . 0.72 „ Creatin is prepared by treating meat cut into very small pieces with cold water as long as anything is dissolved, and the solution evaporated ; the concentrated liquid, filtered, furnishes creatin. This body occurs in rectangular prisms, without taste or odour, soluble in 74 parts of cold water, but more soluble in boiling water. On being boiled with strong acids it furnishes creatinin. HOI + C 4 H 9 N 3 2 =H 2 + C 4 H r N 3 0,HCl Chlorhydrate of creatinin. This chlorhydrate decomposed furnishes creatinin as a crystalline alkaline substance, more soluble than creatin in both water and alcohol. Creatinin may be reconverted into creatin by boiling with lead oxide. It forms with zinc chloride a combination which is but slightly soluble in cold water. According to Neubauer, creatin does not exist in flesh, but creatinin only, and the creatin which is found is formed by the transformation of the creatinin. Creatinin also exists in urine, and in the muscles of the Crustacea. XANTHIN. 387 On submitting creatinin to a prolonged ebullition with baryta water another substance is formed, called sarcosin. H 2 -f C 4 H 9 N 3 2 =CH 4 N 2 + C 3 H 7 N0 2 Urea. Sarcosin. This body crystallizes in rhombic crystals, which are colourless, very soluble in water, somewhat soluble in alcohol and insoluble in ether. Sarcosin melts at a temperature above 100 D , and is volatile. It possesses the characters of glycocol and its homologous sub- stances. Inosic Acid. — The mother liquor of creatin is acid, and has an odour of meat broth. Extract of meat treated with baryta furnishes on evaporation inosate of barium, and the liquid contains inosite. The formula of inosic acid is usually given as C 5 H 8 N" 2 6 , though some authors regard it as C l0 H 14 N 4 O n (21-269). Xanthin. — C 5 H 4 N 4 2 . To prepare this substance muscular tissue is well beaten, and alcohol and water successively added as long as anything is dissolved. These two liquids are now united and heated, in order to coagulate the albumen and drive off the alcohol. The liquid is filtered, and lead subacetate added. The precipitate is collected, washed, and decomposed with hydrogen sulphide while suspended in water. The filtered liquid is boiled and evaporated. The xanthin deposits in a non-crystalline mass. It can also be prepared from the liver. Xanthin is soluble in cold 388 ANIMAL CHEMISTRY. water, alcohol, and ether. It forms with acids salts which are generally crystallizable ; it is precipitated even from very dilute solutions by mercuric chloride or nitrate. It dissolves in alkaline liquids. If calcium hypo- chlorite be added to one of these solutions, a greenish precipitate is formed which becomes brown and then disappears. This reaction is quite delicate, and a useful test. OTHER TISSUES. Cells. — The cells are the simplest structures of .the body. Their mass is very minute, and their form variable. They are not always enclosed by an envelope, and they vary in their chemical nature. They contain one or more nuclei, and when new a gelatinous liquid (protoplasm), capable of contractile movements under the influence of chemical agents, of electrical or mechanical forces. If old, they contain different matters, derived either from modifications of the proto- plasm or the introduction of foreign substances. The protoplasm coagulates after death. It appears to contain myosin, also other albuminoid, fatty, and saline constituents. Areolar Tissue is chemically characterized by the action which hot water has upon it. At first it swells, assumes a jelly-like appearance, and finally dissolves, producing gelatin, which, on cooling, is of a tremulous consistency. tissues. 389 Dilute inorganic acids and dilute alkalies also effect this transformation. There is believed to exist in this tissue a substance (collagene, glutine, geline) analogous with ossein, which, in contact with hot water, furnishes gelatin ; also a substance (elastin) not furnishing gelatin. « Tannin and mercury dichloride form with these matters imputrescible compounds. Cellular tissue is converted into a transparent and colourless jelly by the action of strong acetic acid ; but the fibre is not attacked, for if the acid be saturated with ammonia water it reappears in its ordinary condition. The elastic tissues do not dissolve even after an ebulli- tion of sixty hours, and do not furnish gelatin. Hydrochloric acid dissolves them, turning brown at the same time. With sulphuric acid they furnish leucin and not gelatin. This may be obtained quite pure by boiling cellular tissue with water, then with acetic acid, and macerating the residue with a dilute alkaline solution. To the product thus obtained the name of elastin has been given. The mucous areolar tissue differs chemically from ordinary conjunctive tissue, in that it does not furnish gelatin on being boiled with water. The reticular tissue of the cutis contains the pig- ment called melanin, the colouring matter of the skin. This tissue is not reproduced completely where destroyed, but is replaced by cellular tissue, and the cicatrix is due to the fact that this latter tissue is colourless. 390 ANIMAL CHEMISTRY. The epidermis furnishes gelatin on boiling with water. It appears to contain iron, and H. P. Floyd (84-34-179) has found it to contain in the negro twice as much of this element as in whites. Sulphuric acid softens and dissolves it, nitric acid colours it yellow, alkalies dissolve it, the sulphides render it of a brown colour, and silver salts blacken it. The epidermis, hair, bristles, feathers, nails, horns, and epithelium have an almost identical composition. Epi- dermis. Epi- thelium. Hair and Bristles. Nails. Feathers. Horn. Carbon 50.34 51.53 50.00 51.00 52.42 50.94 Hydrogen . 6.81 7.03 6.40 6.82 7.21 6.65 Nitrogen 17.22 16.64 17.00 17.00 17.89 16.28 Oxygen and sulphur . 25.63 24.80 26.60 25.18 22.48 26.13 100.00 100.00 100.00 100.00 100.00 100.00 The horny tissues are formed of cells containing nuclei which have united and dried. Indeed, when these different tissues are treated with alkaline solu- tions, ovoid cells are seen, each containing a nucleus. Sulphuric acid likewise renders this structure apparent. This tissue leaves about 1 to 1.5 per cent, of ash on ignition. Horn treated -with fused potassium hydrate and with dilute sulphuric acid, furnishes tyrosin and leucin. Hydrochloric acid renders it blue, nitric acid yellow ; aqua regia attacks it with energy. Feathers possess the same general properties. The colour of the feathers is due to different pigments, rarely soluble in water, sometimes in ammonia, and CARTILAGINOUS TISSUE. 391 ordinarily in alcohol. They generally contain less oxygen and more silica than horn and analogous tissues. Hair has the same composition and chemical char- acters as horny tissue. Its colour is due to oils of various tints. With age this oily secretion ceases to be produced and the hair whitens ; the white colour seeming to be due to the fact that the tubes contain no secretion, but are filled with air. The fatty bodies of the hair are formed from the volatile acids of perspiration, and also of margarin, olein, and stearic acid. Hodgkinson and Sorby ob- tained (28-222-592) from black hair and feathers a black pigment, to which they ascribe the formula Hair contains 0.5 to 2.0 per cent, of inorganic sub- stances, containing a considerable proportion of iron and small quantities of silica. Mulder found in epi- dermis an organic sulphur compound he called keratin. Cartilaginous Tissue. — The cartilages are ordi- narily formed of a flexible tissue, whose composition is not greatly different as to its organic constituents from that of the preceding substances, though varying in organic composition with age and in the different parts of the body : — Carbon 50.91 Oxygen 6.96 Nitrogen 14.90 Oxygen 27.23 100.00 392 ANIMAL CHEMISTRY. Hoppe-Seyler found in a proximate analysis of cartilage from the knee of a man aged twenty-two years : — H 2 75.59 Organic matter . . . .24.87 Inorganic matter . . . 1.54 100.00 This tissue is not homogeneous ; under the micro- scope it appears composed of a colourless fibre and cells containing granulated protoplasm. The matter of the cells is different from the gelatinous substance forming their envelopes. It does not dissolve in boiling water even under pressure. The cartilaginous substance proper, cartilagein, fur- nishes, with boiling water, a substance which resembles gelatin in its composition, but from which it differs in several characteristics, and especially by its giving a precipitate with acids, lead acetate, and alum, while gelatin gives no reaction with these substances. It is called by the name of chondrin. Chondrin turns the plane of polarization to the left. Treated with hydro- chloric acid it furnishes a variety of glucose (chondro- glucose) and various nitrogenous substances of which little is known. A distinction has lately been made between the cartilages just spoken of and the fibro-cartilages. These last contain a fibrous matter without nuclei, differing NERVE TISSUE. 393 from the ordinary cartilaginous substance by producing with boiling water a substance which is but slightly precipitated by tannin. The fibro-cartilage of the knee must also be distinguished from the preceding, from the fact that it produces gelatin with boiling water. Cartilaginous tissue contains 55 to 15 per cent, of water, 2 to 5 per cent, of fatty bodies, and 1.5 to 6 per cent, of mineral substances. Nerve Tissue. — Of it are composed the nerves, ganglia, brain, and the spinal cord. It is observed to contain cells and cylindrical tubes ; these are formed of an envelope of areolar and fibrous tissue and of a semi-liquid medullary substance (myelin of Yirchow), which refracts light strongly, and is sometimes observed to flow out when a nerve is cut. These tubes are united in bundles which are enveloped in a colour- less, lustrous, and fibrous membrane sometimes called neurilemma. This membrane may be rendered apparent by treat- ing nervous tissue with a cold dilute solution of caustic potassa, which dissolves the nervous substance with the exception of the neurilemma. This membrane is dis- solved, on the contrary, by hydrochloric acid and strong sulphuric acid ; it is not coloured yellow by nitric acids. The ganglions of the nervous centres are formed of cells of variable size, composed of a very thin envelope and a nucleus containing a dense liquid, in which are granules in suspension. Concentrated alkaline solutions attack and dissolve 394 ANTMAL CHEMISTRY. the nerve cells and tubes. Strong inorganic acids shorten and thicken the fibres. An aqueous solution of iodine colours them bright yellow. A mixture of mercurous and mercuric nitrates renders them rigid and tenacious. The reaction of the nerves appears to be neutral during life, it becomes acid after death, and finally, at the moment when putrefaction sets in, it has an alkaline reaction. Different investigations made recently on the matter of the nerves and brain have shown that we are far from completely understanding its compositions ; Liebrich's protagon is now regarded as a mixture of W. Midler's cerebrin and lecithin, and the same may be said of Kohler's myeloidin and myeloidinic acid. The Constituents of the Brain, more or less constant and normal, thus far determined with apparent certainty are : — ■ Water, — albuminoid bodies resembling myosin, — elastin (?) — neurokeratin, — nuclein, — collagen, — soluble albumen, coagulating at 75°, — cerebrin and lecithin, — glycerinphosphoric acid, — fats (?), — cholesterin, inosit, — hypoxanthin, xanthin, kreatin, — lactates, — vola- tile fatty acids and uric acid. Inorganic substances : calcium, potassium and magnesium phosphates, iron oxide, silica, alkaline sulphates, sodium chloride, and fluorine. (Horsford.) Although very extended and repeated investigations of the chemical nature of the brain have been made, CONSTITUENTS OF THE BRAIN. 395 it yet remains, chemically, one of the most incompletely- known animal organs. It was W. Mliller who first obtained the nitrogenous neutral body from the brain called cerebrin. It is extracted on coagulating by heat an aqueous extract of the cerebral substance ; this coagulum is separated and washed with water, and treated while boiling with a mixture of alcohol and ether, and filtered hot, White flakes separate out of the solution, which contains cholesterin, lecithin, and cerebrin. This matter is the cerebric acid of Fremy. Cerebrin has the formula It is dissolved by sulphuric acid, the solution being of a purple colour. It is rendered resinous by hydro- chloric acid, and is transformed by boiling nitric acid into an oil which solidifies on cooling. Grobley claims to have also found cerebrin in the yolk of eggs. E. Bourgoin (60-[2] 21-482) purifies cerebrin from the phosphorous compound which ordinarily adheres to it by treating the same with a sufficient quantity of strong alcohol, and gradually warming ; the cerebrin dissolves before the alcohol begins to boil, and the phosphorous compound deposits itself on. the bottom of the vessel ; the cerebrin separates out of the decanted solution on cooling. The cerebrin should be again subjected to a similar treatment. Bourgoin regards the protagon of Liebreich (36-1865-647) as a mixture of cerebrin with this phosphorous compound. Pure cerebrin shows the following composition : — 896 ANIMAL CHEMISTRY. Carbon 66.35 Hydrogen 10.96 Nitrogen . . . . . 2.29 Oxygen 20.40 Lecithin, though a constituent of the brain, is best obtained' from the yolk of eggs. It is an imperfectly crystallizable body, easily fusible, with a waxy lustre, soluble in ether and alcohol, and in general very easily decomposed. There appear to be various lecithines with different radicles ; one of the most common appears to have the radicle of stearic acid, its empirical formula being C 44 H 90 NPO 8 . (Thudicum.) The mineral salts constitute about 5 per cent, by weight of the brain in a dry state. When the brain is in full action the elimination of phosphorus appears to be greater than when it is in repose, since the quantity of alkaline phosphates in the urine increases. The composition of the spinal cord, of the medulla oblongata, of the nervous fibres and ganglions is very similar to that of the cerebral substance. The medulla oblongata contains the largest proportion of fatty bodies. Osseous Tissue. — The bones are formed of solid mineral matter (about 70 per cent.), and of an organic cartilaginous tissue, in which is found a principle called ossein, furnishing gelatin with boiling water. The bony structure is pierced with numerous cavities. Many are visible to the naked eye ; others are extremely minute canals, which penetrate in all directions, forming a complete network, which admits of communication CONSTITUENTS OF BONE. 397 between the most remote points of the structure ; these canals are concerned in the nutrition of the tissue. The medullary cavity and the cells of spongy hones have a membranous cellular tissue and blood-vessels. The canaliculi contain only nerves and blood- vessels. Marrow is formed, according to Berzelius, of — Fat .96 Blood-vessels, membrane ... 1 Extractive substances .... 3 100 According to Eylerch, the fatty matter of marrow is constituted of three ethers of glycerin, whose acids are the palmitic, medullic, and elaidic. The first is the most abundant. Bones deprived of their fat and periosteum, are, according to Berzelius, composed of — Man. / Calcium phosphate (tribasic) 53.04 Mineral portion Calcium carbonate . 11.30 J Magnesium phosphate . 1.16 \ Sodium chloride and carbonate 1.20 Organic portion ( Cartilage (ossein) . 32.17 (Blood-vessels . . 1.13 100.00 Ossein has, as a special characteristic, the property of being transformed by the action of boiling water into M 398 ANIMAL CHEMISTRY. gelatin. The membrane which covers the walls of the osseous canals is formed of an albuminoid substance insoluble in boiling water. Nitrogenous bodies derived from the blood-vessels and nerves are also found in the bones, as well as fatty matters. On treating bones with a dilute alkaline solution the ossein is dissolved, and the mineral portion remains, retaining its original shape. The composition of bone does not vary greatly with age, except that the hard and compact portion of the bones diminishes in aged people, and is replaced by a spongy and more brittle material ; also in children it contains more water, and is more elastic. It has been observed that in lower animals the proportion of calcium carbonate increases with age. The composition of the bones of different species of animals differs but little ; yet the bones of birds and herbivorous mammalia are richer in calcium salts than the bones of carnivora and reptiles. The bones of the limbs contain more inorganic mineral matter than those of the trunk ; the humerus and femur contain more than the other long bones ; these also contain less fatty matters than the short bones : the flat bones contain the largest proportion of water. According to Fremy, the bones are not formed by an incrustation of the mineral portion in the cartilaginous tissue, as is generally believed, but by a juxtaposition of osseous matter, particle by particle ; for the rudimen- tary parts of the bones of the foetus have the same GELATIN. 399 composition as the bones of full-grown persons, and the composition of the bones does not essentially vary with C. Aeby (18-[2] 10-408) also is of the opinion that the cartilage and calcium phosphate of the bones are not combined, and that the organic foun- dation of the bones simply induces ossification with- out entering into chemical relations with the calcium phosphate. Bones are used in the arts for the manufacture of animal charcoal or bone black, phosphorus, and gelatin. Grease is likewise extracted from them. They also serve as material for a great variety of useful and fancy articles. Gelatin. — The organic portion of bones is separated from the mineral portions on treatment with dilute hydrogen chloride. The salts are thereby dissolved; this organic substance alone remains, and, while retain- ing the form of the bone, is flexible, yellowish, and translucent. This substance, formed almost exclusively of ossein, becomes hard on drying, and again pliable and elastic Avhen placed in water for a short time. Submitted to the action of boiling water, it is trans- formed into gelatin. In making gelatin bones are first treated with boiling water. The grease is thereby separated out and removed. The bones are then placed in a digester with water, and submitted to a pressure of several atmospheres ; the gelatin is almost completely dissolved, and the mineral portion remains insoluble. These degelatinized bones form an excellent manure. 400 ANIMAL CHEMISTRY. The transformation of ossein is more rapid with, the bones of a young animal than those of an adult. The ossein is not combined with the calcium, as can be very easily proven, for, if a few grammes of bones and a quantity of ossein equal in weight to that which exists in these bones be treated with boiling water the transformation is as rapid in one case as in the other, during the first part of the process. The proportion of gelatin produced by the bone then diminishes ; but this is due to the fact that the calcium salts of the exterior layers protect the interior portions from the action of the boiling water ; but if the surface of the bone be scraped the action of the boiling water again commences. Pure gelatin, C 6 H 10 N 2 O 2 (?), when dry is colourless, or very slightly yellow ; elastic and insoluble in alcohol and ether. It swells in cold water, and dissolves in boiling water. It turns the plane of polarization to the left. The solution, on cooling, changes into a gela- tinous mass, provided it has not been boiled too long with water. One per cent, of gelatin is sufficient to form a jelly; and sulphuric acid* converts it into gly- cocol. It forms with tannin an insoluble and impu- trescible compound, and this chemical action is the basis of the art of tanning. C. Yoit (11-8-297) has shown that gelatin is capable of partially replacing albumen and fat, as a food. Pathological States. — In arthritis, or gout, the arti- culations become encrusted with concretions, called arthritic calculi. EXOSTOSIS CARIES. 401 ARTHRITIC CONCRETIONS. Water . 10.3 Animal matter . . 19.5 Uric acid . . 20.0 Sodium hydrate . . 20.0 Lime .... . 10.0 Potassium chloride . 2.2 Sodium chloride . 18.0 100.0 (Sebastian). Exostosis is an affection in which osseous tumours are developed on the bone. An analysis gave : — Exostosis. The bone in the vicinity. Organic substance . . 46.0 41.6 Calcium phosphate . 30.0 41.6 „ carbonate . 14.0 8.2 Soluble salts . . 10.0 8.6 100.0 100.0 In caries of bone the inorganic portion of the bone is destroyed, while the organic portion remains almost intact. We owe to Yon Bibra the following analyses of cases of caries : — 402 ANIMAL CHEMISTRY, Tibia at the point amputated. Tibia taken 6 centimetres from the joint. Portion of the Astragalus taken from the centre of the caries. Inorganic substances 61.80 42.10 18.54 Organic „ 38.20 57.90 81.46 100.00 100.00 100.00 In rachitis the mineral portion is removed to such an extent that the bones become incapable of supporting the body. The ossein is also changed, since boiling water no longer furnishes gelatin with these bones. Bones of a rachitic child, analyzed by Marchand, contained : — Vertebra. Femur. Radius. Sternum. Cartilages 75.22 72.20 71.25 61.20 Fat 6.12 7.20 7.50 9.34 Calcium phos- phates 12.56 14.78 15.11 21.35 Magnesium phosphates . 0.92 0.80 0.78 0.72 Calcium car- bonate 3.20 3.00 3.15 3.70 Calcium sul- * ) phate . Sodium sul- I 0.98 1.02 1.00 1.68 phate , ) Sodium chlo- ride, calcium fluoride, iron, etc. 1.00 1.00 1.20 2.01 100.00 100.00 100.00 100.00 DENTAL TISSUES. 403 Osseous tissues gradually decompose after death. In time nothing remains but the mineral portions, yet this action is very slow, as organic matter has been found in bones buried for several centuries. The character of the soil or other medium in which bones are placed has a great influence upon the rapidity of this change. The ossein which has not yet been wholly decom- posed has the same characters as ossein from fresh bones; it is capable of furnishing gelatin. Dental Tissues. — Three subsb.noes are distin- guished in the teeth : the dentine, ' which forms the greater part of the teeth ; the cement, which covers the cervix and roots ; and the enamel The cement has a structure, similar to that of the bones. It has a cavity which contains the nerves and blood-vessels, and in which arise the little canals which ramify and penetrate to the surface of the teeth. Treated with an acid, it parts with its inorganic con- stituents, and there remains an organic residue capable of furnishing gelatin, according to some authors, though denied by Hoppe-Seyler. The cement has the com- position, substantially, of the bones. The enamel is hard and brittle ; it contains about 90 per cent, of calcium phosphate, and a considerable quanity of calcium fluoride, and only 2 to 6 per cent, of organic substances. When treated with dilute hydrogen chloride, the calcium phosphate dissolves, and prismatic fibres remain, which are not attacked by boiling water, and comport themselves like epithelium, :04 ANIMAL CHEMISTRY. Berzelius found in the teeth : — Organic matter . Calcium phosphate Magnesium phosphate. Calcium carbonate Sodium „ and chloride Water, animal matter, alkali (traces) 28.0 64.4 1.0 53 1.3 0.0 100.0 The inorganic portion, according to Fremy, con- sists of: — Ash Calcium Magnesium Calcium Phosphate. Phosphate. Carbonate. Dentine . 76.8 70.3 4.3 2.2 Cement . 67.1 60.7 1.2 2.9 Enamel . 96.9 90.5 traces 2.2 Minute amounts of chlorine and fluorine exist especially in the enamel. The following are more recent analyses by Aeby : — Cement. Dentine. Calcium phosphate . 91.32 93.35 „ oxide . 5.27 0.86 „ carbonate . . 1.61 4.80 „ sulphate . . 0.09 0.12 Magnesium carbonate 0.75 0.78 Ferric oxide . . 0.10 0.09 Organic substances . 27.70 3.60 CHEMISTRY OF THE EYE. 405 Molar teeth, appear to contain more mineral matter than incisors (Bibra). The relation of the calcium phosphate to the calcium combined with carbonic acid, and in some analyses with chlorine and fluorine, suggests an analogy between the composition of the enamel and the mineral apatite. CHEMISTRY OF THE EYE. The sclerotic coat dissolves almost completely in boiling water, and the liquid obtained is a solution of gelatin and chondrin. The cornea furnishes chondrin with boiling water ; it also contains myosin and an alkaline albuminate. The choroid coat, on being boiled with water, also furnishes gelatin. The following analysis of the crystalline humour was made by Berzelius : — Water .... . 58.0 Albuminous matter . 35.9 Aqueous extract and salts . . 2.4 Alcoholic extract . 1.3 Membrane . . 2.4 100.0 The albuminous matter coagulates in certain cases, and cataract is then produced, on account of the opacity of the crystalline lens. 406 ANIMAL CHEMISTRY. Lassaigne analyzed the opaque crystalline lens of the eye of a horse, and found — Coagulated albuminous matter . . 29.3 Calcium phosphate . . . .51.4 „ carbonate . . . .1.6 Portion soluble in water . . .17.7 100.0 The iris is composed chiefly of fibrin. * The retina is an expansion of the optic nerve, which has the composition — Water 92.90 Albumen 6.25 Fatty substances 85 100.00 Aqueous Humour of the Eye. — Berzelius found in this liquid — Water 98.10 Lactate, chloride of sodium . • 1.15 Sodium hydrate 0.75 100.00 It also contains a small quantity of albumen. pus. 407 EXUDATIONS. The name exudations is given to liquids formed at the expense of the blood, in consequence of an inflam- mation which arrests the circulation of this fluid. Exudations differ from transudations by containing fibrin, much albumen and blood globules, and in being more dense. pus Is a yellowish-white, viscous, neutral liquid, or alkaline if the pus is unhealthy. It is formed, like the blood, of a liquid {serum) in which are corpuscles. These are about .01 mm. in diameter ; they contain a viscous liquid and nuclei enclosed in a membrane. The colourless globules of mucus and lymph resemble these corpuscles ; they are designated in general as cystoid corpuscles. Pus exposed to the air usually becomes acid, pro- ducing margaric, butyric, and other homologous acids. Ammonium sulphide is afterwards formed, and the mass undergoes putrid fermentation. 408 ANIMAL CHEMISTRY. Pus contains 15 to 16 per cent, of soluble matter, the most important of which is albumen. The existence of a substance called pyin has been detected in it. but according to Lehman this body is an abnormal product. It generally contains a larger proportion of soluble salts than the serum of the blood. Boedecker found in a pus slightly alkaline : — Water . . 88.76 Albumen ..... . 4.38 Pyin. ..... 4.65 Fatty bodies and cholesterin 1.09 Sodium chloride 0.59 Other alkaline salts . 0.32 Earthy phosphates . 0.21 100.00 Certain varieties of pus have the property of impart- ing a blue tinge to linen. Fordos has discovered the principle which produces this coloration : it is a eiystalline substance which he has named pyocyanin. Pus swells, and assumes the appearance of gelatin on being mixed with ammonium hydrate. This reaction distinguishes it from mucus. Pure pus, placed in a vessel and allowed to remain for several hours, separates into two layers. The lower, curdy layer contains the globules and the solids; the upper, opalescent layer constitutes the serum. PU& 409 C. Eobin gives the following analysis of the serum in 1,000 parts: — Water .'._.. 937.86 to 970.55 Sodium phosphate . 3.11 J5 4.66 Phosphate of soda . traces » 2.22 Earthy and ammonio- magnesium phosphates . 0.50 J> 2.20 Sulphates and carbonates of sodium and potassium 1.87 5> 3.11 Salts of iron and silica .16 5J .96 Salts with organic acids formiates, butyrates. valeriates, etc. traces » 1.00 Leucin, tyrosin, and ex- tractive substances 15.00 J> 20.00 Serolin . 1.00 )> 8.30 Cholesterin 3.50 J> 10.00 Fatty bodies . 10.00 )> 19.00 Lecithin . 6.00 >J 10.00 Meta-albnmen and serin . 11.00 J? 48.00 Among the extractive subst ances there have been found : Paraglobulin, tyrosin, leucin, xanthin, urea, glucose (in diabetes), bilirubi n, uric * md chlorrho- dinic acids (in necrosis), and a special pus product, hydropsin. 410 LIST OF OKIGINAL AUTHORITIES. 1. Annalen der Chemie und Pharniacie ; y. Liebig u. Wohler. 2. Annalen der Physik und Chemie von Poggendorf . 3. Archiv der Pharmacie. 4. Bulletin de la societe d'en- conrag. 5. Bulletin de la societe de Mulhouse. 6. The Engineer. 7. Chemisches Centralblatt. 8. Chemical News. 9. Comptes rendus. 10. Deutsche Industriezeit. 11. Zeitschrift fiir Biologic 12. Gewerbeblatt, Sachsisches 13. ,, Breslauer. 14. „ Hessisches. 15. „ "Wurtemberger. 16. Wieck's Illustr. deutsch. Gewerbztg. 17. Journal de Pharmacie et de Chimie. 18. Journal fiir praktische Chemie. Bayr. Industrie u. Grewerbe- blatt. London Journal of Arts. Lehrbuch der physiolog. Chemie. Gorup-Besanez. Fourth Ed. 1878. Mittheilungen des Gewer- bevereins fiir Hannover. Reimann's Farberzeitung. Pharmaceut. Centralhalle v. Hager. 25. Photogrr. Archiv. v. Liese- 19. 20. 21. 22. 23. 24. 26. Polytechn. Centralblatt. 27. Mechanics' Magazine. 28. Dingier' s Polytechn. Journal. 29. Polytechn. Eotizblatt v. Bottger. 30. Milchzeitung (Dantzic). 31. Practical Mechanics' Journal. 32 . Quarterly Journ . of the Chem. Soc. LIST OF ORIGINAL AUTHORITIES. 411 33. Ackermann'sGewerbezeitung 34. Repertory of patent inven- tions. 35. Technologiste. 36. Jahresbericht der Chemie 37. Zeitschrift fur analytische Chemie. 38. Journal of Applied Chemistry. 39. Zeitschrift des allgem. oster- reich. Apotheker-Yereins. 40. Pharmaceut. Zeitschr. f. Russland. 41. Wien. Acad. Ber. 42. Neues Jahrbuch fur Phar- macie. 43. Berg- and huttenmann. Zeitung. 44. The Lancet (London). 45. Der Bierbrauer (Leipsic), 46. Archiv. Pharm. 47. Gazetta Chimica Italiana 48. Eisner's Chem. -techn. Mitt- heilgn. 49. Industrieblatterv. Hager und Jacobsen. 50. Photographische Mittheilun- gen v. H. Yogel. 51. Zeitschrift des Yereinsfur die Riibenzuckerindustrie 52. American Jour, of Pharmacy. 53. Photographische Correspon- ded v. Hornig. 54. Bulletin beige de la photo- graphie par Deltenre- Walker. 55. London . Royal Society Pro- ceedings. 56. Chemisch-Technisch Reperi- torium. • 57. Neue Deut. Gewb.-Zeitg. 58. Wagner's Jahresbericht der chem. Technologie. 59. "Wurzburg. gemeinn. Woch- ensclir. 60. Berichte der deutschen chem. Gesellschaft. 61. Proceedings of the French Association for the Ad- vancement of Science. Lyon Medicale. Scientific American. American Artizan. Journal fur Gasbeleuchtung. Moniteur Scientifique Badische Gewerbezeitung. Der Naturforseher (Berlin). Deutsche Weinzeitung. Annales du Genie civil. Les Mondes. Annales de Chimie et de Physique. Deutsche Gerberzeitung. Chicago Pharmacist. Neues Repert. der Pharm. Nature (London). Racquet's Modern Chemistry. Schweizer. Zeitschr. f . Phar- 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79, 80. 81. 82. macie. Yir chow's Archiv. American Journal of Science. Zeitschrift f. d. gesammten Eaturwissenschaften. Zeitschrift fur Chemie. 83. Photographic News. 412 LIST OF ORIGINAL AUTHORITIES. 84. Brit. Journ. of Photography. 85. New Remedies. 86. Philadelphia Photographer. 87. London Medical News. 88. Monitenr Industriel. 89. Jahresbericht der Thier- chemie. 90. Centralblatt f. d. Papier- fabrik. 91. Engineering. 92. Propagation Indnstrielle. 93. Journal de 1' Agriculture p. Barral (Paris). 94. Proceedings of the Am. Pharm. Ass'n. 95. Revista Pharmaceutica (Buenos Ayres). 96. Journal for Pharmaci (Copenhagen). 97. Bulletin de la Societe Chi- mique (Paris). 98. Popular Science Monthly. 99. Journ. of the Franklin In- stitute. 100. American Chemist. 101. Kun st und Glewerbe (Nurem- berg). 102. NeuesHandwoerterbuchder Chomie. 103. Jacobsen's Chem.-tech. Repertorium. 104. Philosophical Magazine (London). 105. Pharm. Journal and Trans- actions. 106. Pharm. Zeitung (Bunzlau). 107. Zeitschrif t f ur Chem. Gross- gewerbe. 108. Die Chem. Industrie auf der Austellung in Philadel- phia. 109. Zeitschrift fur Physiolog. Chemie. Hoppe-Seyler. 110. Moniteur de la teinture. INDEX. PAGE. Acenapthene, Ci2Hio=i54. . 38 Acetamide, C2 H 5 NO=S9- . J 3 6 Acetanilide, Cs H a NO=i35. 130 Acetic oxide C4 H6 O3 =102 103 Acetochlorhjdric glycol 63 Acetone, C 3 H6 0=58 99, 108 Acetyl acetate, C4 N9 O3 ... 103 Acetyl chloride, C 2 C1H 3 O. 103 Acetyl hydride or aldehyd, C 2 H 4 0=44 86 Acetylamine, C2 H5 N=43.. 129 Acetylene, C2 H2 =26. . . . . 18 Acetylide, cuprous 19 Acid,acetic, C2 H4 Og =60. . 99 Acid, aconitic, Cq Hq Oq =95 174 Acid, acrylic, C3 H4 O2 =72. 91 Acid, adipic, C6 H10O4 =148 91 Acid, alloxanic, C4 H4 N 2 O5 125 Acid, alpha-cymic, C11H14O2 91 Acid, amalic, C6 H7 N2 O4 . . 169 Acid, anchoic, C9 H16O4 =188 93 Acid, angelic, C5 Hs O2 =108 91 Acid, anisic, Cs Hs O3 =152. 92 Acid, arabic, C6 HioOg —342 217 Acid, arichidic, C20H40O2 . . 90 Acid, atropic.Cg Hs O2 =148 164 Acid, benzoic, C7 H6 O2 =126 91, 109, 126 Acid, benzoglycolic 126 Acid, butyric,C4 Hs O2 . ..90, 108 Acid, caffetannic 196 PAGE. Acid, camphic, CioHi6020=9i 168 Acid, campholic, C19H18O4 . . 91 Acid, camphoric,CioHi804 41, 93 Acid, caprylic, Cs H16O2 ... 90 Acid, caproic,C6 H12O2 =116 90 Acid, capric, C10H20O2 =172 90 Acid, carballylic, C6 Hs 06 . 95 Acid, carbamic, CH3 NO2 ... i-l Acid, carbazotic,(Picric) CH 3 N 3 07=229 33 Acid, carbolic,C6 H6 = 94. 32 Acid, carbonic, C2 H 3 = 62. 92 Acid, catechic 196 Acid, cerotic, C2TH54O. ..90, 180 Acid, chelidonic, C7 H4 C>6 .. 95 Acid, chlorbenzoic,C7 H5 CIO = i3 -5 l6 ° Acid, cholalic, C24H40O5 =408 95 Acid, cholesteric, Cs H10O5 .. 95 Acid,choloidic,C24H3s04 = 390 94 Acid, cinnamic, C9 Hs O2 = 148 91, in Acid, citraconic, C5 He O4 93, 121 Acid, citric, C 6 H 8 07,H 2 = 192+18 120, 95 Acid, coccinic, Q3H26O2 ... 90 Acid, comenic, C6 H4 O5 .. . 95 Acid, coumaric, C9 Hs O3 . . 93 Acid, croconic, C5 H 2 O5 . . 95 Acid, crotonic,C4 H6 2 ..91, 178 Acid, cumic, C10H12O2 = 164 91 414 INDEX. PAGE. Acid, cyanacetic, C 2 H 3 (CN)0 3 =85 103 Acid, cyanhydric,HCN = 2 7. 161 Acid, dextroracemic 117 Acid, dialuric, C4 H4 N2 O4 125 Acid, dinitrobenzoic, CtH 4 (N0 2 )2 2 =2I2... 1 10 Acid, doeglic, C19H36O2 =296 91 Acid, elaidic 177 Acid, erucic, C22H42O2 =338. 91 Acid, ethalic, C16H32O2 =256 179 Acid, ethylsulphuric, C 2 H 5 HSO4 =126 71 Acid, formic, CH2 O2 =50.98, 90 Acid, fumaric,C4 H4 O4 =116 93 Acid, gallic, C7 H 6 O5 . .95, 197 Acid, glucic, Q2 Hg O9 =306 186 Acid, glyceric, C 3 H 6 O4 . . . 93 Acid, glycolic, C2 H4 O3 .60, 92 Acid, guaiacic, C6 Hg O3 . . . 92 Acid, gummic, C12 H22 On.. 217 Acid, hippuric, C9 H9 NO3 .. 125 Acid, insolinic, C9 Hg O4 . . . 94 Acid, itaconic, C5 H6 O4 . . 121 Acid, lactic, C3 H6 O3 ..92, 122 Acid, lauric, C12H24O2 =200 90 Acid, leucic, C6 H12O3 = 132. 92 Acid, lichenstearic, C9 H14O3 92 Acid, lithic, C5 H4 N4 O3 . . 123 Acid, lithofellic, C20H36O4 . . 93 Acid, malic, C4 H6 O5 =134 115 Acid, malonic, C3 H4 O4 . . . 93 Acid, mannitic 183 Acid, margaric, C17H34O2 ... 177 Acid, meconic, C~ H4 O . . . . 143 Acid, melissic, C30H60O2 . . 90 PAGE. Acid, mellitic, C4 H2 O4 94 Acid, mesoxalic, C3 H2 O5 . . 94 Acid, metagummic 217 Acid, monochloracetic, C2 CI H 3 O2 =94.5 201 Acid, moringic, C15H28O2 . . 91 Acid, morintannic 196 Acid, mucic, C6 H 3 Og =205 95 Acid, myristic, Ci4H2gC>20. . ■ 90 Acid, cenanthalic, C7 H14O2 90 Acid, cenanthic, Ci4H2g03 . . 92 Acid, oleic, CigH^C^ =282. 91 Acid, opianic 127 Acid, oxalic, C2 H2 O4 . ..93, 112 Acid, oxamic, C2 H3 NO3 . . 11 Acid, oxybenzoic, C7 H6 O3 195 Acid, oxybutyric, C4 Hg O3 92 Acid, oxycuminic, CioH^Os 92 Acid,oxynapthalic, C10H6 O4 94 Acid, oxy valeric, C5 H10O3 . . 92 Acid, palmitic, C16H32O2 .90, 177 Acid, parabanic,C3 H2 N2 O3 125 Acid, parafinic, C24H4g02 . . 23 Acid, paralactic 122 Acid,paramalic, C4 H4 O4 . . 116 Acid, paratartaric 117 Acid, pectic, C16H22O5 =294. 218 Acid, pectosic 218 Acid, pelargonic, C9 HigC>2 ... 90 Acid, phenic, Cg H 6 0=94. . 32 Acid, phenylsulphuric, C 6 H 6 oIs=i7 4 32 Acid, phloretic, C9 H10O3 . . 92 Acid, phtalic,Cg H 6 O4 =150 94 Acid, physetoric, C16H30O2 .. 91 Acid, picric, C 6 H 3 (NO2 )a O 33 INDEX. 415 PAGE. Acid, pimelic, C7 H12O4 .... 93 Acid, pinaric,C2oH3o02 =3° 2 4 1 Acid, pinic, C20H30O2 = 302 . . 91 Acid, piperic, C12H10O4 =218 94 Acid, propionic, C3 H6 O2 78, 90 Acid, prussic, HCN=27 161 Acid, pyrogallic, C6 H6 O3 . . 198 Acid, pyroligneous 100 Acid, pyromeconic, C5 H4 O3 92 Acid, pyrotartaric, C5 H 8 O4 = i3 2 93, n7 Acid, pyroterebic, C6 H10O2 . . 91 Acid, pyruvic, C3 H 4 O3 =88 92 Acid, quinic, C7 H12O6 =144- 93 Acid, quinotannic 196 Acid,racemic,C4 H 6 06 =150 117 Acid, ricinoleic, C18H34O3, 92, 180 Acid, roccellic, C17H32O4 . . 93 Acid, salicylic, C7 H 5 O3 195,32,92 Acid, sarcolactic 122 Acid, scammonic, C15H28O3 92 Acid, sebic, C10H18O4 =202.. 93 Acid, sorbic, C6 Hg O2 =112. 91 Acid, stearic, C18H36O2 . .90, 177 Acid, suberic,C8 H14O4 =174 93 Acid, succinic, C4 H 6 O4 93, 115 Acid, sulphocarbolic, C 6 H 6 S04=i74 33 Acid, sulphoglucic 185 Acid, sylvic, C20H30O2 =302. 41 Acid, tannic, C2tH220i7=6i8 J96 Acid, tartaric,C4 H6 06 . ..116, 95 Acid, tartrelic, C4 H4 O5 . . . 117 Acid, tartronic, C3 H4 O5 . . 94 Acid, terebic,C7 H10O4 =158 93 Acid, terechrysic, C6 He O4 94 PAGE. Acid, thionuric,. C 4 H 5 N0 3 S03=i9S.... 125 Acid,* thymotic, C11H14O3 .. 92 Acid, toluic, Cs Hg O2 =136 91 Acid, trichloracetic, HC 2 Cl 3 2 = 163.5 102 Acid, tropic, C9 H10O3 =166. 164 Acid, uric,C5 H4 N4 O3 = 168 123 Acid, valeric or valerianic, C6 H10O2 = 102 109, 90 Acid, veratric, C9 HiqOs ... 94 Acid, xylic, C9 H10O2 =150. 91 Acids 95 Acids, aromatic 91 Acids, fatty 90 Acids, general methods of preparation, 96 Acids, organic 90 Acids, defined 95 Acids, polyatomic 112 Acids, pyro 97 Aconitina, C30H47NO7 =533. 165 Albumen 228 Alcohol, amy lie, C5 H12O . 56, 45 Alcohol, benzyl, C7 H 8 0=io8 46 Alcohol, butyl, C4 HioO = 64 45 Alcohol, eery 1,C27H560 = 396 45 Alcohol, cholesteryl 46 Alcohol, cinnyl, C9 H10O . . 46 Alcohol, cuneol 46 Alcohol, cymol, C10H14O . . 46 Alcohol, melissic, C30H62O. . 180 Alcohol, methyl, CH4 O. .45, 46 Alcohol, myricyl, C30H62O.. 45 Alcohol, octyl, Cs Hi 8 0=i30 45 416 INDEX. PAGE. Alcohol, ordinary, or ethyl, C 2 H 6 0= 4 6 49 Alcohol, propyl, C3 H 8 O.... 45 Alcohol, sexdecyl, C16H34O.. 45 Alcohol, sextyl, C6 H14O 45 Alcohol, vinyl, C2 H 6 0=46 45 Alcohol, xylyl,C8 HioO= 122 46 Alcohols, diatomic 58 Alcohols, monatomic 44 Alcohols, polyatomic. , 59 Alcohols, sulphur 82 Alcohols, selenium 82 Alcohols, tellurium 82 Alcohols, tetratomic 59 Alcohols, triatomic 64 Aldehyds 86 Alizarin, C10H6 O3 =174. . . 39 Alkalamides 136 Alkaloids 127 Allantoin, C4 H 6 N 4 O3 = 158 124 Alloxan, C4 H4 N 2 O5 =160. 125 Alloxantin, Cs H10N4 O10. . 123 Allyl iodide, C 3 H 5 I=i68. . 57 Allyl sulphide, C$ HioS= 114 57 Allyl sulpho-cyanide, C4H 5 NS = 99 57 Allylamine, C3 H7 N=57. . . 127 Allylene, C3 H4 =40 20 Amane, C5 Hi 2 =72 23 Amber 26, 42 Amides 136 Amidoxypropyl, C 3 H4(NH 2 )0=72 75 Amines 133 Ammelide 172 PAGE. Ammonia aldehydate, C 2 H 4 ONH 3 =6i 87 Ammonia citrate of iron. . . 121 Ammoniacum 43 Ammonias, compounds 131 Ammonium, cyanate,CH4 N 2 172 Ammoniums 137 Ammoniums, quarternary. . 136 Amvgdalin, QoH^NOn 193 Amyl, acetate, C7 H14O3 . . 56 Amyl, chloride, C5 HnCl . . 56 Amyl, hydride, C5 Hi 2 =72. 23 Amylamine, C5 Hi3N = 87. . 121 Amylene, C5 Hio= 70 23 Anhydride, tartaric, C4 H4O5 =132 117 Aniline 30, 127, 131 Anthracene, Ci4Hio=i78. .29, 39 Arabin Ci 2 H 22 On=342 217 Arbutin C13H16O7 =284 193 Aricina C23H26N2 O4 =397- . 129 Arnicin 42 Aromatic compounds 89 Arsines 128 Asphalt 26 Assafcetida 43 AtropiaCnH23N03 =289.164,129 Balsams 41 Bases organic, 125 Bases quarternary, 136 Bassorin 218 Belladona 164 Benzene C6H6 =78 27 Benzine 24 Benzoic aldehyd, C7 H 6 O.. 86 Benzol, C 6 H 6 =78 27 INDEX 417 PAGE. Benzone 119 Benzonilrile no Benzyl chloride 126 Benzylene 20 Bezoar 267 Bidecane 28 Bidecyl hydride 23 Bilifulvin 257 Bilirubin 257 Biliverdin 257 Bile 250 Bile, action on food 258 Bitumen 26 Biuret 172 Blood 272 Blood, action of different gases on the 291 Blood, chemical pathology of the 294 Blood, coagulation of 276 Blood, gases of the 288 Blood globules 281 Blood, iron of the 287 Blood, uses of 293 Bones 399 Borneol 58 Brain constituents 394 Brandy 52 Brucia 161, 129 Butane 23 Butter 179 Butyl hydride 23 Butylamine 128 Butylene 20, 22 Cacodyl 79, 105 Caffeia (caffein) 130, 168 PAGE. Campholic alcohol 117 Camphor, artificial 37 Camphor 40 Camphor, monochlor 41 Camphor, oxy- 41 Camphor of Borneo 58 Cantharidin 168 Candles 1 76 Cannabin 42 Caoutchouc 36, 43 Caprylamine 127 Caramel 190 Caramelane 190 Caramelene 190 Caramelin „ . . 190 Carbo-hydrates, defined 7 Carbon dioxide 313 Caries 401 Carbonic ether 74 Cartilagein 392 Casein, animal 226, 233 Casein, vegetable 219, 234 Castor oil 180 Castorin 42 Cellulose (cellulin) 202 Cerasin 217 Cerebrin , 395 Cetene , 23 Chitin 184 Chloral 87 Chloral hydrate 88 Chloroform . . 47 Chloropropyl ! 15 Cholera 296 Cholesterilene 255 Cholesterin 255 418 INDEX PAGE. Cholesterophan 169 Cholin 251 Chondrin 227, 214, 392 Chondroglucose 392 Chyle 269 Chyme 268 Chymosine 247 Cinchonia (cinchonine).i29, 156 Cinchonicia (cinchonicine) . . 158 Cinchonidia (cinchonidine) 158, 129 Cinnamene 38 Coagulum 281 Codeia 146, 129 Colchinia 163 Colloidin 375 Collodion 208 Colophony 41 Compound ammonias 131 Conia (conine) 141, 129 Conicin 129 Coniferin 193 Convolvulin 193 Conylia 141, 129 Cotarnin 147 Cream of Tartar 116 Creatin 188, 386 Creatinin 386 Creosote 34 Cresofol 29, 34 Crotonylene 20 Cumene 28 Cumidin 127 Cuprous acetylide 20 Curari 163 Curarina 162 PAGE. Cyanopropyl 115 Cyclamin 193 Cymene 38 Cymogene 24 Cymol 41 Cystin 353 Daphnin 193 Daturia, (atropia) 164, 129 Decane 24 Dextrin 212, 214 Dental tissue 403 Diabetes 327, 347 Diastase 212 Diethylamine 128 Diethylpropyl 15 Diethylenic diamine 170 Digestion 237 Digitalin 166 Digitin 166 Dimethylphosphine 128 Draconyl 38 Dropsy 297 Dulcite, (dulcose) 183, 181 Duodecylene 23 Dysentery 266 Dystisin 253 Elaidin 175 Elaine 175 Elayl 21 Elemi 43 Emetia 167 Emetics 119 Emydin 226 Ergotin 42 Erythrite 49 Esculin 193 INDEX 419 PAGE. Essence of mirbane 29 Essence of thyme 34 Essential oil of cloves 37 Essl. oil of bergamot 37 Essl. oil of copaiba 37 Essl. oil of cubebs 37 Essl. oil of elemi 37 Essl. oil of juniper 37 Essl. oil of lemon 37 Essl. oil of orange 37 Essl.#oil of pepper 37 Ethal 179 Ethane 13, 15, 23 Ethene 13, 15 Ether, acetic 73 Ether, butyric 81 Ether, chlorhydric 75 Ether, common 70 Ether, cyanhydric 77 Ether, ethyl 70 Ether, formic 81 Ether, hydriodic 76 Ether, hydrosulphuric 83 Ether, cenanthylic. ..'. 81 Ether, oxalic 74 Ether, oxamic 117 Ether, sulphuric 70 Ether, valerianic 81 Ether, vinic 70 Ethers 69 Ethers, simple 69 Ethers, compound 73 Ethers, miscellaneous 81 Ethers, mixed 38 Ethine 13 Ethyl 15 PAGE. Ethyl chloride ^. 75 Ethyl cyanide 77 Ethyl formiate 9 Ethylglycol 61 Ethyl-hexyl ether 84 Ethyl hydride 23 Ethyl iodide 76 Ethyl mercaptan 83 Ethylmethylaniline 30 Ethyl oxide ". . 69 Ethyl sulphide 83 Ethylamine , .... 132, 127 Ethylene 21 Ethylene bromide 61 Ethylene chloride 76 Ethylene oxide 62 Eucalin 182 Eye, chemistry of the 405 Excrements 265 Excretin 265 Extosis 401 Exudations 407 Fats 174 Fatty acid series 90 Ferment, bile 258 Fermentation, acetic 100 Fermentation, alcoholic . . .49, 181 Fermentation, gallic 197 Fermentation, lactic 122 Ferrocyanide of potassium . 172 Fibrin 226, 23 1 Flesh 382 Flour 215 Food, respiratory 223 Food, plastic 224 Food, transformation of. . . . 321 420 INDEX. PAGE. Formene 23 Frankincense 43 Fulminates 54 Fusel or fousel oil 56 Galactose 187, 182 Gas, illuminating. 21 Gasolene 24 Gastric juice 242 Gasterase pepsin 247 Gelatin 234, 399 Glucosane 185 Glucose 180, 182, 184, 343 Glucose in the liver 323 Glucosides 192, 184 Glue 235 Gluten 216 Glycerin 64 Glycocol, zincic 126 Glycogen 214, 250, 324 Glycol, amyl. . . 59 Glycol, butyl 59 Glycol, diethyl 61 Glycol, ethyl 61 Glycol, hexyl 59 Glycol, monochlorhydric. . . 62 Glycol, octyl 59 Glycol, ordinary 59 Glycol, propyl 123 Grape sugar 182 Guano. 124 .Gum 216 Gum arabic 217 Gum resins 41 Gun-cotton 207 Haematin 286 Haematocrystallin 225 PAGE. Haemoglobin 284, 226 Helicin 194 Heptyl hydride 23 Heptane 23, 24 Heptylene 22 Hexadecane 24 Hexadecyl hydride 24 Hexane ,23 Hexy lene 22 Hexyl hydride 23 Hoffmann's anodyne 73 Homologous series 12 Honey 192 Hydrides 23 Hydrocarbons 18 Hydrocarbides 18 Hydrocarbides, extra-terres- trial 40 Hydrocephalus fluid 374 Hydrogen carbides 18 Hydropical fluid 375 Hydrosulphuric Ether 83 Hyosciamine 164 Ictithin 226 Indican 342 Indigogen 343 Indiglucin 343 Indigo 130 Inosite (inosin) 182 Intestinal concretions 267 Intestinal fluids 264 Intestinal gases 265 Inulin 214 Iodomorphia 145 Iron of the blood 287 Isatin 38 INDEX. 421 PAGE. Isologous series 12 Isomerism 8 Jalapin 193 Jervia 163 Kerosene 24 Ketones 40 Lactide 123 Lactose orlactin.... 191, 182 Leather 197 Legamin 219 Leucocythaemia 296 Levulosan 190 Levulose 187, 182 Lichenin 214 Lymph 270 Madder 39 Maltose 182 Mannitane 183 Mannite 181, 183 Marsh-gas 23 Meconin 143, 147 Melampyrite 181 Melanin 389 Melezitose 182 Melitose 182 Mercaptans 82 Metalbumen 225 Metamerism 9 Metaterebenthene 38 Metastyrol 38 Methane 13, 15, 23 Methenyl 15 Methyl 15 Methyl acetate 9 Methyl chloride 47 Methyl cyanate 131 PAGE. Methyl hydride 23 Methylamine 131 Methylethylamine 128 Methylphosphine 128 Methylpropyl 15 Milk 376 Molasses 189 Monamines 133 Monochlorcamphor 41 Monochlorhydrin 66 Morphia (Morphine) 143, 129 Mucin 227 Mucus 372 Murexide 125 Muscular power 316 Muscular tissue 283 Musculin 232 Myosin 232 Mycose 182 Naphtha 24 Naphthalamine 128 Naphthalin 27, 38 Narceia 148, 129 Narcotina '. . 129 Neocytes 337 Neurin 257 Nevrilemma 393 Nicotina 139, 129 Nicotyl 140 Nicotylia 139, 129 Nitrilebases 124 Nitrobenzol 29 Nitrogenous substances.... 223 Nitroglycerine 66 Nitryls, or cyanhydric ethers 134 Nonane 23 422 INDEX. PAGE. Nonyl hydride 23 Nonylene 22 Nutrition 316 Nutrition, role of mineral compounds in 330 Octane 23 Octylglycol 59 Octyl hydride 23 Octylene 22 Oils, fatty 174 Oils, essential 36 Olein 175 " Oleomargarine" 179 Oleo-resins 42 Opium 142 Orcin 193 Organizable substances 205 Organometallic compounds. 78 Ossein. 226, 234 Osseous tissues 399 Oxamide 74 Oxanthracene 39 Oxycamphor 41 Oxygen 311 Pancreatic juice 261 Pancreatin 262 Para-arabin 192 Paralbumen 226 Plants, respiration of 201 Plants, nutrition of 204 Polyamines 170 Polymerides 9 Polymerism 9 Populin 193 Potassium, binoxalate 114 Potassium, ferrocyanide . . . . 170 PAGE. Paraffin , 22, 24 Papaverin 129, 148 Paramorphia 148 Paramylene 22 Parapeptone 249 Pectin 218 Pectose 218 Pentadecane 24 Pentadecyl hydride 24 Pepsin 227, 247 Peptones 225, 249 Petroleum 24 Phenol 32 Phenol, potassic 32 Phenol, trinitric 30 Phenyl 30 Phenyl hydrate 32 Phenylamine 127 Phlorizin 193 Phlorylol 34 Phosphines 128 Phtalidamine 127 Picrotoxin 160 Pinite. 181 Piperidine 141 Piperine 141 Pitch, Burgundy 42 Plethora 295 Potassium, formiate 88 Propane 13, 15, 23 Propenyi 15 Propine 13. Propone 13 Propyl 15 Propyl hydride 23 Propylamine 127 INDEX. 423 PAGE. Propylene 22 Proplene iodide 64 Protein 225 Ptyalin 212, 227, 238 Pus 407 Pyin 227, 407 Pyocyanin 40S Pyrethrin 42 Pyrocatechin 352 Pyrolignite 106 Pyroxylin 207 Quercite 181 Quercitrin 193 Quinia, (quinine) 151, 129 Quinicia 154, 129 Quinidia 129 Quinidia, oxalate of 155 Quinoidin 158 Quinolein, (quinolin) 130,153,157 Quinovin 193 Rachitis ..-.-. 402 Radicles, defined 14 Radicles, organometallic ... 78 Radicles, organometalloid . . 81 Reagent, Fehling's 187 Reagent, Haines' 187 Reagent, Trommer's 186 Resins 25, 41 Respiration 272, 301 Retinasphalt 25 Retinite 25 Rhigolene 24 Rice 216 Rochelle salt 118 Rosanilin 31 Rutylene 20 PAGE. Rye 216 Saccharide 186 Saccharoses 182 Salicin 194 Saligenin 194 Saliva ; 237 Saponification 176 Saponin 193 Scurvy 297 Semen 371 Serosity 374 Serum 278 Sinapolin 58 Sinnamin 58 Soaps 176 Sodium ethyl 80 Sodium sulphocarbolate. ... 33 Solanidia (solanidine) 165 Solania (Solanine),. . .165,129,193 Sorbin 182 Spermaceti. . 179 Spirit of Mindererus 105 Stannethyl 79 Stannethyl iodide 79 Starch 210 Stearin (stearine) 174 Stearine candles., 176 Stercorin 257, 265 Stibines ; 128 Stibyl 119 Strychnia (strychnine). .159, 129 Styrol 38 Sucrates 190 Sugars 181 Sugar of milk 191, 182 Sweat . , 370 424 INDEX, PAGE. Synovia 374 Syntonin 229, 232 Tannin 196, 193 Tartar emetic I .y.C/-**€-l Taurin ...7. 254 Teeth 403 Tetrachloropropyl 15 Tetradecane 24 Tetradecyl hydride 24 Tetradecylene 22 Tetrethylammonium 133 Thebaia 148, 120 Theia (theine) 168, 130 Theobromin. 169, 130 Thymol - 34 Thiosinnamin 58 Tissues 388 Tissues, areolar 388 Tissues, recticular 387 Tissues, cartilagenous 391 Tissues, nerve 393 Tobacco 140 Toluene 28 Toluidin 127, 130 Transpirations 370 Trehalose 182 Trichlorhydrin 66 Trichloroxypropyl 15 Tridecane 27 Triedecyl hydride ,,,,,,.,,, 24 PAGE. Tridecylene * 22 Triethylamine 135 Triethylarsine 128 Triethylenic, diamine 170 Triethylstibine 128 Trimethlamine 128 Trimethylphosphine 128 Tunicin 184, 209 Turpentine 35 Tvpes, organic 10 Typhoid fever 266, 296 Urinary calculi 353, 368 Urinary deposits 352, 364 Urine 333 Urine, analysis of 356 Urochrome 343 Uroglaucin 343 Urorubrohsematin 352 Urrhodin 343 Uroxanthin 343 Wax 179 Whiskey 52 Wines 32 Wood spirit 49 Xylene 28 Xylidin 127 Xylyl alcohol 46 Zinc, ethyl 79 Zinc, glycol 79, 126 ■ . CONGRESS 00055543172 ■n §m