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MANUALS 
 
 Students of Medicine. 
 
CLINICAL 
 
 CHEMISTKT 
 
 AN ACCOUNT OF THE 
 
 ANALYSIS OF BLOOD, UKINE, MORBID PRODUCTS, ETC. 
 
 WITH AN EXPLANATION OF SOME OF THE 
 
 CHEMICAL CHANGES THAT OCCUR IN 
 
 THE BODY, IN DISEASE. 
 
 CHARLES HENEY RALFE, 
 
 M.A., M.D., CANTAJ)., 
 
 FELLOW OP THE ROYAL COLLEGE OF PHYSICIANS, LONDON ; ASSISTANT 
 
 PHYSICIAN AT THE LONDON HOSPITAL; FORMERLY DKMONbTRATOR 
 
 OF PHYSIOLOGICAL CHEMISTRY IN THE MEDICAL SCHOOL OF 
 
 ST. GEORGE'S HOSPITAL. 
 
 ILLUSTRATED WITH 16 ENGRAVINGS. 
 
 HENRY C. LEA'S SON & CO, 
 FHILALELPHIA, FA. 
 

SIR ANDREW CLARK, Bakt., 
 
 LL.D., M.D., ETC., ETC., 
 
 Senior Physician of the London Hospital, 
 
 THIS WOEK IS DEDICATED 
 
 AS A SLIGHT ACKNOWLEDGMENT OF THE MANY VALUABLE 
 
 SERVICES RENDERED BY HIM 
 
 TO THE 
 
 MEDICAL SCHOOL OF THE LONDON HOSPITAL. 
 
PEEEACE. 
 
 This work, as its title implies, lias been written 
 for a practical purpose, viz., to furnish students and 
 practitioners with a concise account of the best 
 methods of examining chemically, abnormal blood, 
 urine, morbid products, etc., at the bedside or in the 
 hospital laboratory. It has been purposely made as 
 simj^le as possible. 
 
 In spite of the disi^aragements of such eminent 
 clinical teachers as Gra\'es and Trousseau, chemistry 
 has become more and more important to the physician 
 as a means of elucidating many pathological con- 
 ditions, or of determining the character of the morbid 
 changes effected in tissues or secretions. Indeed, it is 
 becoming more and more evident that we must 
 eventually look to Chemistry for information with 
 regard to the primary alterations that occur in fluids 
 and tissues, and which are the first step in every 
 disease. But even if original investigation iia this 
 direction is not engaged in, the student or prac- 
 titioner will find that by making a chemical exami- 
 nation of the secretions, abnormal products, etc., when- 
 ever he has an opportunity, he gains such considerable 
 
viii Clinical Chemistry. 
 
 insiglit into the nature of the morbid processes p)*o- 
 ducing them, as enables him more effectually to 
 comprehend their nature and modify their ill efiects. 
 
 As few medical schools are now without physio- 
 logical and chemical laboratories, in which students 
 can obtain the necessary manipulative skill, I have not 
 cumbered the text with minute directions with i-egard 
 to apparatus, or with instructions for the conduct of 
 such simple operations as weighing, evaporation, fil- 
 tering, drying precipitates, etc., as the students to 
 whom this work is addressed will have already gone 
 tlj rough a course of practical training. Those, however, 
 who have not done so will find the necessary instruC' 
 tions in my work, " Demonstrations in Physiological 
 Chemistry," which I wrote for the purpose of instruct- 
 ing second-year students in the practical operations of 
 the laboratory. 
 
 London, September, lSb3. 
 
CONTENTS 
 
 CHAPTER I. ^^^.^ 
 
 PAGE 
 
 Section A.-Organic Coxstitukxts of the Animal Body 1 
 Skgtion B.-Inorganic Constituents of the Animal 
 Body ' 
 
 CHAPTER II. 
 Section A.-Chemical Reactions ok Chief Organic 
 
 Constituents op the Animal Body -8 
 
 Section B.— Inorganic Constituents »* 
 
 CHAPTER ni. 
 Blood— Chyle— Lymph— Milk ^-^ 
 
 CHAPTER IV. 
 
 Morbid Conditions of Urine 103 
 
 CHAPTER V. 
 Morbid Conditions of the Digestive Secretions . . 173 
 
 Morbid Products 
 
 CHAPTER VI. 
 
 235 
 
Clinical Chemistry. 
 
 CHAPTER I. 
 
 Section A. — Organic Constituents of the Animal 
 Body, 
 
 1. Object of study. — It is proposetl, in the 
 present work, to confine our attention to those points 
 of chemistry in so far as they relate to the study of the 
 chemical phenomena concerned in eflecting abnormal 
 qualitative and quantitative changes in the constitu- 
 tion of the tissues and fluids of the animal body, and 
 their practical bearing in relation to clinical medicine 
 and pathology. Before, however, proceeding to the 
 main object of study of this branch of science, it will 
 be necessary to consider briefly the proximate and 
 ultimate composition of the principles of the animal 
 body^ and the nature of the processes which produce 
 the various decompositions and variations that are 
 constantly occurring under normal conditions. 
 
 2. Clicniical composition of the tissues 
 and fluids. — If we submit a tissue or fluid to the 
 action of heat, we find that with a moderate degree, 
 100° C, it loses weight and becomes dry; the loss of 
 weight is due to removal of water ; the dry residue 
 repi'esents the solid material present in the substance 
 submitted to analj'sis. If the heat be now raised con- 
 siderably, the dry residue chars or carbonises, showing 
 the presence of organic matter ; if the heat be long con- 
 tinued this undergoes complete combustion, leaving an 
 
 B 
 
2 Clinical Chemistry. [Chap. i. 
 
 asli which resists all farther change on the application 
 of heat ; this ash, which consists of mineral salts, is 
 known as the inoeganic residue. If, however, we 
 submit the tissue or fluid to a slightly more complex 
 analysis, we shall find that the organic and inorganic 
 residue consist of various substances, each of which 
 can be removed by appropriate means. For instance, 
 if, after having driven off the water, we treat the dry 
 residue with ether, we find that the etherial solution 
 will yield, on evaporation, a greasy residue, which 
 represents the fats extracted from the tissue or fluid. 
 If, after the removal of the fatty matters, we treat 
 the original residue successively with boiling alcohol 
 and boiling water, we shall find, on evaporating the 
 alcoholic solution and the aqueous solution respec- 
 tively, that each will give a residue containing sub- 
 stances soluble in these agents, and which have been 
 extracted from the original mass by their means. 
 These substances, which are various, are designated as 
 EXTRACTIVES, and consist chiefly of certain organic 
 substances such as urea, uric acid, ki-eatin, etc., and 
 the SOLUBLE salts of the inorganic constituents, whilst 
 to separate them from each other further means of 
 analysis have to be employed, and special tests ap- 
 plied to identify their characteristic reactions. After 
 the fatty matter and the alcoholic and aqueous extrac- 
 tives have been removed, there remains an elastic and 
 somewhat horny mass, which consists of proteid 
 material (albumin, fibrin, globulin, etc.), and which 
 chars on being burnt, leaving a residue of such salts of 
 the inorganic constituents which are insoluble in 
 boiling water, and some of the soluble salts not taken 
 up by extraction by water. By this elementary 
 analysis we have learnt, first, that the tissue or fluid 
 consists of water and solids ; secondly, that the solids 
 consist of organic and inorganic substances, and that 
 these may be further divided : (1) The organic into 
 
Chap. I.] Orgaxic Constituents. 3 
 
 proteid substances, fatty matters, and extractives ; (2) 
 the inorganic into soluble and insoluble saline con- 
 stituents. The next step in the investigation is (1) to 
 separate and distinguish the constituents present in 
 each group from each other ; in the Protcids, the 
 various albumins ; in the Fats, the saponifiable fats, 
 cholesterin, etc. ; and in the Extractives, the urea, uric 
 acid, etc., and the composition of the Soluble and In- 
 soluble salts ; (2) to determine the nature, special 
 characteristics, and ultimate chemical composition of 
 each substance so sejiarated. 
 
 3. Composition and constitution of or- 
 ganic substances. — There is no essential difference 
 between organic and inorganic chemistry. Organic 
 chemistry is simply the chemistry of carbon compounds, 
 and accordingly we find that the organic principles we 
 meet with in the animal body consist of carbon united 
 in various proportions with hydrogen, oxygen, nitro- 
 gen, and some loss abundant elements, such as sulphur, 
 phosphorus, and iron. 
 
 4. IVitrog:cnous and iion - nitrog^enous 
 compounds. — The carbon comjiounds, or organic 
 princiiDles, for purpose of convenience ai'e divided into 
 two distinct groups, viz. : (1) The non-nitrogen- 
 ous, and (2) the nitrogenous ; those in which the 
 element nitrogen is absent, and those in which it is 
 present. Both these groups are represented by the 
 principles which form the basis of the animal tissues 
 and fluids, the first by the starchy, saccharine, and 
 oleaginous principles, the second by the proteid or 
 albuminous. These principles, which are usually dis- 
 tinguished by the term proximate, after fulfilling their 
 purpose in the economy, undergo a series of changes 
 {nietaholic), are broken up and oxydised, and are 
 finally reduced ; the former to carbonic acid and water, 
 the latter to carbonic acid, water, and ammonium cai'- 
 bonate (urea). But before this final reduction is 
 
4 Clinical Chemistry. [Chap. i. 
 
 reached, various intermediate products are produced ; 
 thus, the oxydation of the non-nitrogenous principles 
 yields lactic acid OjIIgOs, oxalic acid O2H.O4, acetic 
 acid CgH^O^, formic acid CH2O2, and ultimately 
 carbonic acid CHgO,. The nitrogenous group, in ad- 
 dition to the formation of products identical with the 
 above, yield by oxydation a series of bodies, the lowest 
 term of which is urea, the ammoniated form of car- 
 bonic acid ; thus, leucin CgHigNOg, and kreatin 
 O4H9N3O2, and perhaps uric acid O5H4N4O3, are 
 recognised antecedents of urea CH^NgO. 
 
 5. €las$)ilication of the compounds of 
 carbon. — These are (1) the compounds of carbon 
 with hydrogen, or the hydrocarbons ; (2) the com- 
 pounds of carbon with nitrogen. 
 
 (1) The hydrocarbons. — The classification of 
 these bodies is based upon the atomicity of carbon, 
 which, being a tetrad element, requires 4 atoms of 
 hydrogen, or some other monad, for its full saturation, 
 i.e., to satisfy all its combining powers ; the fully 
 satisfied hydrocarbon molecule will therefore be repre- 
 sented by the formula OH4. Each additional atom of 
 carbon i-equires, however, only two additional atoms 
 of hydrogen to maintain the saturation, because a 
 portion of the combining power of each carbon atom 
 is employed in linking the carbon atoms together. 
 The following diagram illustrates this important 
 theory, which, it must be remembered, is applicable to 
 all kinds of carbon compounds. 
 
 CH4. CaHg. CJgHg. C4H10. 
 
 CHHH (SJiS^ 
 
 CHHHH. { gg™ j CHH 
 
 CHH 
 
 \ CHH 
 
 CHHH [qJJJJJJ 
 
 It follows from this that all carbon compounds 
 
Chap. l.| O/i'OAiY/C C\k\STITUK.\TS. 5 
 
 lurange themselves in series, tlie members of which 
 differ from one another by CHa or by some multiple 
 of CH... Thus we have formic acid CHnOa, acetic 
 acid C2H4O2, propionic acid CgHi-Oo, and so on. 
 Series of this kind are termed homofogous series, and 
 the members are said to be homoloc/ues of one another. 
 
 (a) Hydrocarbon radicals. From the above con- 
 siderations, we deduce, as the general formula for a 
 saturated hydrocarbon, the expression C„H2„ + 2, in 
 which n may denote any number of atoms. If a 
 hydrocarbon contains a less number of hydrogen 
 atoms than the above formula requires, it is, or may 
 be, a radical; tliat is, it may exist in compounds, 
 and play therein the part of an elementary atom, 
 ."^ome hydrocarbons, however, which appear from their 
 formulae to be unsaturated are really saturated, or at 
 any rate have an atomicity less than that indicated by 
 the above theory. It is not necessary in this work to 
 enter into the theoretical explanation of this apparent 
 anomaly. 
 
 The atomicity of such a radical must obviously 
 depend on the number of hydrogen, or other monad 
 atoms required to complete it. Thus the radical CH,, 
 is a monad, CH^ a diad, and CH a triad. Their 
 function in compounds is well illustrated by their 
 chlorides, which are strictly comparable to metallic 
 chlorides. 
 
 Chloride of 
 sodium NaCl. zinc Zn"CL bismuth Bi"Cls 
 
 methyl CH3CI. methylene CHXl formyl CHCI3 
 
 Those of the hydrocarbon radicals which contain 
 an even number of hydrogen atoms are cai)able of 
 existing in the separate state, and most, but not all of 
 them, have actually been prepared. Ethylene CoH.„ 
 and acetylene C-.H^i f-i's examples. Those, on the 
 other hand, which contain an uneven number, such as 
 
Clinical Chemistry. 
 
 LChap. I. 
 
 methyl CHg, ethyl CgHg, and glyceryl C3H5, cannot 
 exist in the free state, but only in compounds. 
 
 The names and formulae of a few of the more 
 important hydrocarbon radicals are given in the 
 following table. 
 
 Table of Principal Htdrocarbon Eadicals. 
 
 Monads. 
 
 DiADS. 
 
 Triads. 
 
 Methyl 
 
 series. 
 
 01e£ne series. 
 
 Glycerin series. 
 
 Methyl . 
 
 • CH3 
 
 + 
 
 + 
 
 Ethyl . 
 
 . C2H5 
 
 Ethylene . CaH^ 
 
 Ethine or Acety- 
 lene . . . C2H2 
 
 Propyl . 
 
 . CgHy 
 
 Propylene . CgHo 
 
 Propine or AUy- 
 lene . . . C3II4 
 
 Butyl . 
 
 • C,H, 
 
 Butylene . C^Hg 
 
 Quartine or Cro- 
 tonylene . . CiHo 
 
 Amyl . 
 
 • C5H11 
 
 Amylene . CgH-n, 
 
 Quintine or Va- 
 lerylene . . C5II3 
 
 Hexyl . 
 
 • Cl8Hj(g 
 
 Hexylene . CoH^a 
 
 Sextine or Dial- 
 
 lyl . . . . CeH.o 
 
 (b) Hydrocarbons of the aromatic series. — Benzene 
 CgHg, and toluene Oj-Hg, arc the most important mem- 
 bers of this series. By the rule before given, they 
 should be octads, but they possess the properties 
 of saturated hydrocarbons, and are not therefore to 
 be reckoned among the radicals. From them are 
 derived the important monad radicals, phenyl CgHg, 
 and toluyl C7H7. 
 
 The hydrocarbons, under various conditions of 
 oxygenation and dehydration, form various well-known 
 bodies, as alcohols, aldehydes, and organic acids. 
 
 I. Alcohol. — In an alcohol, a monad, diad, triad, 
 etc., hydrocarbon radical replaces one or more atoms 
 of H in one or more molecules of water. It is, in 
 
Chap. I.] OrGAXIC CONSTITUENTS. 7 
 
 fact, a hydrate of a hydrocarbon radical, as the 
 following show : 
 
 (a) Ordinary ethyl alcohol C,H^O is formed by 
 the monatomic radical ethyl C,Hj replacing one atom 
 
 of H in the single molecule of water thus, -, r^ \ O. 
 
 (6) Glycerin, or glyceryl alcohol CaHsOj, is formed 
 by the triatomic radical glyceryl C3H5'" replacing 
 
 3 atoms of H in the treble molecule of water -^ \ O3 
 thus 3 3 I r\ 
 
 (c) Mannite CgHi^Og, a saturated hexatomic alco- 
 hol, is formed by the hexatomic radical C^Hg replacing 
 
 H I 
 6 atoms of hydrogen in the molecule tt*^ > Og thus, 
 
 II. Aldehydes (alcohol de h)jdro(/enatus). — If an 
 alcohol be submitted to oxydation ib loses two 
 atoms of H, and is converted into a neuti-al body, 
 called an aldehyde, which, ha"VT.ng a great affinity for 
 oxygen, rapidly absorbs it from the air, and is con- 
 verted into an acid. Aldehydes are therefore com- 
 pounds intermediate between the alcohols and the 
 acids. 
 
 (a) Ethyl alcohol CoH^O deprived of 2 atoms of 
 H forms ethyl aldehyde QJ3.^0, and ethyl aldehyde by 
 oxydation yields acetic acid CoH^O^. 
 
 (6) Mannite C^Hi^O^ deprived of two atoms of H 
 forms mannitose C^Hi O^, a sugar isomeric with 
 glucose, dextrose, and other saccharine bodies, which 
 are called carbo-hydrates. These, however, are not all 
 aldehydes (some are ethers, others alcohols), but they 
 are all derivatives of the hexatomic radicals. And 
 mannitose by oxydation yields mannitic acid C6H12O;. 
 Ketones or acetones ai'e bodies isomeric with the 
 
8 Clinical Chemistry. ■ [Chap. i. 
 
 aldehydes, but are distinguished from them with regard 
 to their behaviour with oxygen and hydrogen. With 
 the former, an aldehyde vinites directly to produce an 
 acid ; with a ketone or acetone two acids are formed. 
 With the latter, an aldehyde forms a primary alcohol, 
 whilst with a ketone a secondary alcohol is produced. 
 
 III. Organic acids. — As stated above, the or- 
 ganic acids may be regarded as alcohols, in which a 
 portion of the hydrogen of the radicals is replaced by 
 oxygen. They are therefore formulated as derived 
 from a single, double, or treble molecule of water by 
 the replacement of H, II3 or H, by a monad, diad, or 
 triad oxygenated liydrocarbon radical. 
 
 Examples : 
 
 (a) Acetic acid C2H4O2 is formed by the oxydised 
 radical acetyl C2H3O, which has replaced one atom of 
 
 H in water, thus ^ \t\ ^• 
 
 (h) Gly collie acid CgH^Og is a double molecule of 
 water in which half the hydrogen is replaced by 
 
 glycollyl ^ Vr f Oj. In fact, it is ethylene alcohol 
 
 P FT 1 
 "fT* [ ^2 ii^ which two atoms of hydrogen of ethy» 
 
 lene are replaced by one atom of oxygen. 
 
 (c) Oxalic acid C2H2O4 is a double molecule of 
 
 water in which half the hydrogen is replaced by 
 
 CO) 
 oxalyl TT^ > O2. Here the whole of the hydrogen is 
 
 replaced by oxygen. It will be seen that both these 
 acids are related to ethylene alcohol as acetic acid is 
 to ethyl alcohol. 
 
 Amines. — When a hydrocarbon radical replaces 
 
 the tj'pical hydrogen of the molecule H [ N, the 
 
 H) 
 resulting compound is called a primary, secondary, or 
 
I i.ap. 1.: Okuaxjc Co.ysTJTUEyjs. 9 
 
 tortiary amine, accorcling iis one, two, or three atoms 
 of hydrogen are replactid. Thus, the following 
 amines are obtained by the substitution of the 
 hydrogen of ammonia by methyl. 
 
 Ammonia. 
 
 H l-N. 
 HJ 
 
 Amides. — When an acid radical replaces any part 
 of the typical hydrogen of ammonia, the resulting 
 compound is called an amide. As some of the 
 amides play a very important part in the animal 
 economy, it is necessaiy to study their constitution a 
 little more closely. 
 
 For this purpose it will be convenient to write 
 the formulae of a few important acids in a foi-m "which 
 is a slight variation of that previously used. 
 
 Methylamine. 
 CH3I 
 
 H K 
 
 HJ 
 
 Dimethylamine. 
 CH3] 
 
 CH, I N. 
 H 
 
 Trimetbylamine. 
 CH3] 
 
 CH3fK 
 CH3. 
 
 Primary amine. 
 
 Secondary amine. 
 
 Tertiary amine. 
 
 C.HjO 
 
 HO 
 
 
 Acetic acid 
 
 ^ aHpj, 
 
 0:H0, 
 
 HO 
 
 -I- 
 
 Benzoic „ 
 
 ^ '""^o 
 
 0„H,0 
 
 HO 
 
 + 
 
 HO 
 
 Glycollic ,. 
 
 = C.H^j0. 
 
 C,0, 
 
 HO 
 
 HO 
 
 4. 
 
 Oxalic ,, 
 
 = c,o, ) 
 
 C..,H,0 
 
 HO 
 
 HO 
 
 Lactic „ 
 
 Ho.l ' 
 
 C3O3 
 
 HO 
 
 HO 
 
 INIesoxalic „ 
 
 - c.O},^ 
 
lo Clinical Chemistry. [Chap. i. 
 
 In the above table we have acids of three different 
 kinds, all capable of yielding amides. 
 
 (1) In acetic and benzoic acids we have examples 
 of acids which are simply monobasic. The amides of 
 these acids are called monamides, and are very 
 simple : 
 
 Aeetamide, Benzamide. 
 
 C,H30 1 C,H,0 1 
 
 H J^ N. H [ N. 
 
 H J H j 
 
 They differ from the corresponding amines, just as 
 the acids do from the alcohols. 
 
 (2) Oxalic and mesoxalic acids are examples of 
 dibasic acids. They are, in fact, dihydrates of the 
 radicals CgOg and C3O3. Now these radicals, being 
 diads, are capable of replacing two atoms of hydrogen 
 in the double molecule of ammonia. In this way 
 neutral amides of the kind called diamides are formed. 
 
 Urea is by far the most important of the 
 diamides. 
 
 Oxamide 
 
 Urea 
 
 (oxalyl diamide) 
 
 (carbonyl diamide). 
 
 CAl 
 
 CO] 
 
 hJn, 
 
 hJ 
 
 HJ 
 
 But from all dibasic acids a monad as well as a 
 diad radical may be derived by merely deducting HO. 
 Thus from sulphuric acid, SO2 HO HO, we get not 
 only the diad radical SOj, but also the monad radical 
 SO2 HO. The following formulae exhibit this : 
 
 (SO2)" HO HO 
 (SO2 HO)' 01 
 (SO2)" CI,. 
 
Chap. I.] Organic Coxstituents. ii 
 
 When one of these monntojnic radicals of a 
 dibasic acid replaces the hydrogen of ammonia, a 
 monamide is formed. But, as there is still one atom 
 of replaceable hydrogen attached to the radical, this 
 atom can at any time be replaced by a metal or a 
 hydrocarbon radical, and thus the acid character is 
 not entirely lost. From a dibasic, the acid becomes, 
 in fact, a monobasic one. Acids of this kind are 
 called amic acids. Thus we have 
 
 Oxomic acid. Silver oxamate. Methyl oxamate. 
 
 CO^ HO ] CoO., A,0 ) CO., CH3O ] 
 
 H ^ N. H ^ N. KVN. 
 
 hJ HJ HJ 
 
 (3) Glycollic and lactic acids are examples of acids 
 which are diatomic as to their structure and monobasic 
 as to their properties. Only one of the two typical 
 hydrogen atoms that each contains can be replaced by 
 metals. The diflerence has been indicated in the 
 formulfB given above for the acids by marking the 
 replaceable hydrogen by a plus, and the non-replace- 
 able by a minus, sign. The eflect of this peculiarity 
 is that Uoo monad radicals, one neutral and one acid, 
 can be derived from each acid. These radicals replace 
 one atom of hydrogen in the single molecule of 
 ammonia, just as the monad radicals of dibasic acids 
 do, and monamides are formed ; but these monamides 
 are amic acids if the radical so introduced contain the 
 replaceable atom of hydrogen, or neutral amides if it 
 contain only the non-replaceable atom. Thus from 
 glycollic acid we have 
 
 Glycollamic Potassivmi Metliyl 
 
 acid. glycollamate. glycoUamate. 
 
 C2H2O HO ] anp Ko \ aH,o CH3O ^ 
 
 H In " H In ' H j-N 
 hJ hJ HJ 
 
T2 Clinical Chemistrw [Chap. i. 
 
 Glycollamide. 
 
 and also Q^f> HO ] 
 
 H f-N. 
 HJ 
 
 Analogous to this last we Lave leucin, the neutral 
 amide of leucic acid, which is one of the homologues 
 of glycollic acid. 
 
 Derivations of urea. — A somewhat numerous 
 and complex class of bodies is known, the members 
 of which contain radical, or residues of urea, together 
 with radicals derived from various acids. Many of 
 the deiivatives of uric acid belong to this class, 
 as also do the important compounds kreatin and 
 Jcreatinin. 
 
 In many cases great difference of opinion exists 
 as to the exact structure of these compounds, as they 
 may be desci'ibed by several formulae. Kreatin is 
 generally considered as containing residues of urea 
 and sarcosin (methyl-glycocin). Its formula on the 
 ammonia type may therefore be written as follows : 
 
 CO 
 C,H,0 H.,N 
 
 h- 
 
 h! 
 
 It is capable of taking up the elements of water 
 and splitting into urea and sarcosin. The following 
 comparison of the formulae of these two compounds 
 will serve to illustrate this. The atoms which have 
 to be removed to produce kreatin are printed in italics. 
 
 Sarcosin C.H.O NIT^ CH., 0\ 
 
 Urea CO NH^ K //J' 
 
 Compounds which contain one urea radical ai^e 
 
Chap. M 
 
 Org A xic Cons tituents. 
 
 cjilled monureides. Kreatin is a monureicle, and so 
 are paraban and alloxan, which are obtained by thu 
 oxydation of uric acid. 
 
 Piu-aban. 
 
 CO ) 
 
 c,o. In, = 
 
 
 Radical of oxalic acid. 
 
 CoO.. 
 
 Alloxnn. 
 
 CO ) 
 
 C3O3 ' N, = 
 H,) 
 
 Radical mesoxalic acid. 
 
 CO, 
 
 Radical of uron. 
 COH3N,. 
 
 Radical of urea. 
 
 COH,N.. 
 
 Compounds which contain two urea radicals are 
 called diureides. Allantoin, xanthin, hypoxanthin, 
 and uric acid belong to this class. There is still some 
 doubt as to the exact constitution of uric acid. It is 
 best represented by the hypothetical formula as con 
 sisting of one radical of tartronic acid and two of 
 
 TartroDic acid. Urea. 
 
 C3HA + 2C0H,N, 
 
 Uric acid. "Water. 
 
 C,H,N,03 + 4H„0. 
 
 (2) Compounds of carbon with nitrog^en* — 
 
 Carbon and nitrogen do not directly unite, but there 
 exists a series of compounds containing the monatomic 
 radical CX. called cyanogen. These cyanogen com- 
 pounds may be regarded as derivations of ammonia, 
 and are also connected with the compounds formed 
 by oxalic acid with ammonia. Thus, we saw, when 
 considering the amides, the diad radical of oxalic acid 
 was capable of replacing two atoms of hydrogen in 
 the double molecule of ammonia, forming a neutral 
 amide of the kind called diamide ; thus, urea also 
 belongs to this group of diamides, since in it the diad 
 
14 Clinical Chemistry. [Chap. i. 
 
 radical CO" replaces two atoms of hydrogen in a double 
 molecule of ammonia. 
 
 Oxamide (oxalyl diamide). 
 
 Urea, however, can be formed directly by heating am- 
 monium cyanate ; thus, 
 
 Ammonium cyanate. 
 
 CN 
 
 NH, ^ ^ 
 
 Other compounds of carbon with nitrogen exist, whose 
 exact constitution are not yet precisely determined, 
 (a) Alkaloids : nitrogenous bases believed to belong to 
 the compound ammonias ; they combine with acids 
 to form salts, and double crystallisable salts with 
 platinic chloride. They are derived from the vegetable 
 kingdom, therefore their presence in the animal tissues 
 and fluids when found in them is only incidental. A 
 class of bodies derived apparently from putrefactive 
 changes of animal substances called jytoamines are 
 closely related to these vegetable alkaloids, and may 
 be mistaken for them, especially for strychnia. 
 (/3) Certain Colouring matters, of which the indigo 
 group is the chief. Indol CgHyN, one of the products 
 of pancreatic digestion, stands at the head of this series, 
 of which uro-xanthin or indigogen, one of the urinary 
 pigments, and indican, a glucoside of indigo, are 
 members. (7) A Ibuminous or Proteid substances, such 
 as fibrin, casein, globulin, egg albumin, etc., which 
 form the basis of the tissues and fluids of the body. 
 Some chemists hold that the proteids are formed by 
 
Chap. I.] Organic Constituents. 15 
 
 the combination of an .azotisetl principle, of a dibasic 
 acid character, with di(lerent saline bases in varying 
 j)ropoi"tions. Others, that these substances contain a 
 I'adical called protein, combined with more or less 
 hydrogen, sulphur, and phosphorus, according to the 
 nature of the substance. 
 
 6. Sjiillicsis and analysis. — For many years 
 it was supposed that organic substances could be 
 formed only by the agency of a living organism. In 
 1828, however, Wohler obtained urea by evaporating 
 ammonium cyanate, and since that time chemists 
 have obtained by artificial means a large number of 
 compounds formerly obtainable only from animal 
 or vegetable organisms. These syntheses are effected 
 cither by bringing together molecules of simpler 
 constitution to form a more complex body, as in the 
 case of hippuric acid ; 
 
 Qlycocin. Benzoic acid. Hippuric acid. 
 
 CjH„OH„NHO + C^HjO HO = C^H^O H(C7H50)N HO + H^O. 
 
 or by building up an organic compound from purely 
 inorganic sources ; as Berthelot obtained formic acid 
 by heating carbon monoxide with potassium hydrate 
 at 100° C. 
 
 Cai-bon monoxide. Potassium hydrate. Potassitun formate. 
 
 CO + HKO = ^-^-^ I O 
 
 or, as Kolbe formed acetic acid from carbon di- 
 sulphide. 
 
 In nature this formation of organic compounds 
 from inorganic materials [synthesis) is effected by the 
 agency of the vegetable kingdom. The plant under 
 the influence of the rays of the sun liberates a 
 quantity of oxygen from inorganic constituents such 
 as carbonic acid, water, and ammonium carbonate, 
 
1 6 Clinical Chemistry. [Chap, i, 
 
 which exist in the soil and air, converting them into 
 those saccharine, oleaginous, and albuminous prin- 
 ciples which form its tissues and juices, and which 
 ultimately furnish the animal world with food. For 
 example, carbonic acid by deoxydation under certain 
 conditions may yield mannite ; thus 
 
 6C0, + 7H,0 — 13O = C^HiP^. 
 
 That plants exert this deoxydising power is readily 
 shown by a very simple experiment. If a bunch 
 of fresh green leaves be plunged into a broad necked 
 bottle containing fresh spring-water, or water contain- 
 ing carbonic acid in solution, the bottle turned mouth 
 downwards into a basin of water so as to exclude the 
 air, and the whole placed in strong sunlight for an 
 hour or more, the leaves will become covered with 
 minute bubbles of oxygen, which is derived from the 
 decomposition of the carbonic acid of the water ; 
 the oxygen being set free, while the carbon is 
 absorbed by that plant to form its tissues. In this 
 process of deoxydation, however, a considerable 
 quantity of force derived from the sun's rays is 
 rendered latent, or, to speak more accurately, be- 
 comes potential, one portion being taken up by the 
 liberated oxygen, the other accumulated in the 
 tissues and juices of the plant ; and this force will 
 remain latent till the oxygen and carbon are again 
 united. 
 
 The reunion of carbon with oxygen is effected, 
 either by the direct burning of carbon in oxygen, 
 as takes place when fuel is burnt in our grates or 
 stoves ; or when the carbon elements of food and 
 tissues are submitted to the action of the respired 
 oxygen, and the potential energy assumes the active 
 or hinetic condition of heat and motion, whilst the 
 carbon compounds are reduced again to their original 
 
Chap. I.J OxyOATlON. 1 7 
 
 inorganic state of carbonic acid, water, and anunoniuni 
 carbonate. That animals exhale carbonic acid is 
 demonstrated by the turbidity proiluced by passing a 
 current of expired air through lime water, the lime 
 being converted into calcium carbonate or chalk ; and 
 we know that oxygen is absorbed, from the fact of its 
 diminution in the atmosphere of close, crowded, and 
 ill-ventilated apartments. Thus the vegetable organism 
 is chiefly employed in building up sijntheticnllij in- 
 organic into organic matter, whilst the animal aiia- 
 It/tica/Ii/ reduces organic compounds back again to 
 their original inorganic constituents. These processes 
 of deoxytlation anil oxydation do not at once raise or 
 retluce the various substances to or from their 
 elementary condition. On the contrary, the process is 
 slow and gradual, several intermediate products being 
 formed. De Luca, for example, has shown that in 
 the ripening of the olive carbonic acid is first replaced 
 by certain acids, as oxalic, tartaric, etc., and these by 
 mannite ; which in its turn is deoxydised and con- 
 verted into olein. On the other hand, in the de- 
 composition of albumin a number of intermediary 
 bases and fatty acids are formed, such as uric 
 acid, xanthin, kreatin, lactic acid, and oxalic acid, 
 before the final oxydation to urea and carbonic 
 acid. 
 
 7. Oxydation and fornientatiou. — Although 
 it may be broadly stated that the processes going on in 
 the animal body are finally analytic, still certain syn- 
 thetic processes do occur, as for instance the conversion 
 of carbohydrates into fat, and the elevation of the 
 proteids and peptones into tissues of a more complex 
 form. These processes, however, have not as yet 
 been sufficiently investigated. The downward trans- 
 formation towards carbonic acid and urea, which 
 non-nitrogenous and nitrogenous substances undergo, 
 and to which the term metabolism has been applied, 
 c 
 
1 8 Clinic A l C hem is tr \ '. [Chap. t , 
 
 have been the subject of much study and consider- 
 ation, though our knowledge is still very imperfect 
 in this direction. Formerly it was held that tissue 
 changes depended on the amount of oxygen taken 
 in by the lungs, so that on increased respiration a 
 more intense combustion took place, and metabolism 
 was increased with the production of more carbonic 
 acid and urea, whilst, when respiration was impeded, 
 oxydation was imperfectly performed, and, as a con- 
 sequence, many of the intermediary products, as oxalic 
 acid, uric acid, etc., were not burnt off, but were 
 eliminated in an imperfectly oxydised condition. It is 
 upon this view that most of the chemico-pathological 
 speculations at present held are based. But the view 
 is now gaining ground tliat the cells are to a certain 
 extent independent of the amount of oxygen supplied 
 to them by respiration ; that is to say, though they 
 originally obtain oxygen by the process of respiration, 
 they are able, so to speak, to stow it away, and make 
 use of it independently, under certain vital conditions 
 which bring about intramolecular changes in their com- 
 position, so that reduction is a prior, or at least a 
 simultaneous, process with oxydation. According to 
 this view, instead of increased metabolism being the 
 result of increased oxydation, it is the increase of the 
 intramolecular action in the cells themselves that 
 occasions the demand for oxygen, and a more active 
 condition of circulation and respiration. Accordingly, 
 in fever, the earliest step is the increase of intra- 
 molecular changes in the cells themselves, under the 
 stimulus probably of the zymotic poison ; for when 
 the stored-up oxygen is exhausted, then a demand for 
 a fresh supply causes an increased frequency of pulse 
 and respiration, which continues so long as the 
 stimulus (zymotic) acts on the cells and maintains 
 this abnormal intramolecular activity. The fact that an 
 increase in the amount of urea excreted by the urine 
 
Cl>ai). I.] FeRMENTATIOX. IQ 
 
 often precedes tlie rise of temperature* gives support 
 to this view, as does the fact of the gradual but steady 
 increase of pidse, res])iration, and temperature, during 
 the early stages of febrile action. For the acceptance of 
 this view it is necessary to discard the idea that oxyda- 
 tion occurs in iho blood itself, and to hold that though 
 the quantity of luenioglobin in the blood is the measure 
 of the oxydising power within the body, it is the 
 tissues that determine the amoimt of oxydation. It is 
 not the place to discuss the physiological reasons and 
 experiments on which the view that the oxygen of 
 artwial blood i)asses into the tissues is based, and for 
 whi-^h the reader is referred to Professor Michael 
 Foster's work on " Animal Physiology ;" it will be 
 sufficient to state that it is founded on the fact that 
 oxygen in the arterial blood reaches the tissues -in a 
 state of high tension, while the oxygen in the tissues 
 is in a state of low tension. As a consequence oxy- 
 haMuoglobin becomes i-educed and jiasses on as venous 
 blood. 
 
 Among the processes which induce transformations 
 in complex organic substances, fermentation, next to 
 oxydation, holds an important place. 
 
 There are two kinds of ferments : 
 
 (a) The organised ferments, such as the yeast 
 plant, with powers of growth and reproduction, 
 and whose ferment power cannot be separated 
 irom the ferment organism by filtration or any 
 solvent ; 
 
 (6) The unorga7iisecl or the soluble ferments, which 
 are freely soluble in water, and are incapable of 
 growth and reproduction. These are the salivary, 
 gastric, and pancreatic ferments. 
 
 In the first group the action of the ferment is 
 towards the conversion of the substance into carbons; 
 
 * Einger ; Med.-Chii-. Trans. ISJt). Ralfe ; Mid. Times and 
 Gazette, Jan., 187tJ. 
 
2 Clinical Chemistry. [Chap. i. 
 
 acid, certain intermediate products being formed : 
 tjius, with 
 
 (1) Yeast [Mycoderma cerevisice) : 
 
 Glucose. Alcohol. Carbonic acid. 
 
 CeK^Oe + 2H,0 = 2aHgO + 2CHA 
 
 (2) Lactic acid ferment (Bacteriwrti lacticutn): 
 
 Lactose. "Water. Glucose. Lactic acid. 
 
 Ci^H^-Pn + H,0 = 2C6H,20s + 4C3H6O3 
 
 (3) Butyric acid ferment (Baccillus subtilis): 
 
 \ddf water. ^ut^^ Carbon- Hydroge.. 
 
 2C3Ha03 + 2H2O = CJlfi, + 2CH2O3 + H4 
 
 (4) Ui'ea ferynentation (Micrococcus urece): 
 
 TTrPa WHtPv A.mmoniuin 
 
 urea. watez. carbonate. 
 
 CH4N2O + 2H,0 = (NH),C03 
 
 In the second group, the process of fermentation is 
 from anhydrides into hydrates. These ferments formed 
 in the animal body have been called enzymes, and their 
 action designated as enzymosis, and their nature as 
 enzymic. They may be thus enumerated : 
 
 (1) Ptyalin : 
 
 starch. Water. Dextrin. Glucose. 
 
 (2) Pepsin pancreatin : 
 
 Albumin H- n(H20) = Peptone + Leucin + Tyrosin v 
 Indol, etc. 
 
 (3) Pancreatic fat ferment : 
 
 Suet. Water. Stearic acid. Glycerin. 
 
 CsrH^oOe + 3H,0 ^ sC.gHseO, + C3HA 
 
Cliap. 1.] IXORCANIC CONSTITUENTS. 2 I 
 
 As Ewald has aptly observed, and as we sliall 
 see when we come to the consideration of the changes 
 taking phice in the animal fluids, all purely physio- 
 logical fermentations in the animal body correspond 
 to the unorganised, all pathological to the organised 
 ferments. As, for instance, the undue formation of 
 acetic and lactic acids in the stomach and intestinal 
 canal, and the decomposition of urea in the bladder 
 into ammonium carbonate under the influence of the 
 micrococcus urere. All ferments decompose peroxide 
 of hydrogen and act best at temperatures between 
 20° — 70" C. At much higher, or at much lower, 
 temperatui'es, the action is destroyed. For the 
 growth of organised ferments it is necessary that 
 they should be supplied with sufficient food, of 
 which ammoniacal salts and alkaline phosphates are 
 the chief. 
 
 Sectiox B. — Inorganic Constituents of the 
 Animal Body. 
 
 8. Purposes of the inorganic constituents. 
 
 — The inorganic constituents subserve two important 
 offices in the economy, viz. : — 
 
 (1) Chemical. — In effecting certain metamor- 
 phoses in tlie tissues and fluids, and keeping in 
 solution many of the otherwise insoluble organic 
 principles. 
 
 (2) Mechanical. — In giving strength and firmness 
 to those textures, which, like bone, cartilage, and 
 muscle, form the solid portion of the organism. 
 
 It must not be overlooked, however, that many 
 inorganic substances are incidentally introduced into 
 the body, and are eliminated without subserving ap- 
 })arently any purpose. 
 
2 2 Clinical Chemistry. [Chap. i. 
 
 9. The cttemical rdle of ttie inorganic 
 substances in tlie org^anism. — The fact that, 
 under normal conditions, the same weight of saline 
 constituents are recoverable from the urine and faeces 
 as are introduced during the same period with the food 
 and drink, led physiologists and chemists for a long 
 time to imagine that no change took place in their 
 constitution during their passage through the body, 
 and, consequently, to overlook the part played by the 
 inorganic substances in histogenesis ; or their influence 
 in producing the daily and hourly variations which 
 occur in the chemical composition of normal blood ; 
 or the action, physical as well as chemical, the in- 
 organic constituents of each tissue have on the 
 albumin, fats, water, etc., that compose that tissue, 
 and how far excess or diminution of these con- 
 stituents influences oxydation and nutrition going 
 on in textures. Professor Parkes* was among the 
 first to draw attention to the vastness and com- 
 plicity of the chemical circulation taking place in 
 the body, and the necessity for studying the chemical 
 relations subsisting between the blood and the secre- 
 tions. Attention once drawn to the subject, its im- 
 portance was recognised and astonishment expressed 
 that problems which so manifestly called for solution 
 had been so long ignored. Although this branch of 
 animal chemistry is the least develojoed, still our 
 knowledge in respect to it is advancing. It has now 
 been shown that whilst salts pass with immense and 
 usually uniform rapidity into the circulation, and from 
 thence to tissues, their discharge is by no means so 
 regular, and they are detained for very unequal periods, 
 which apparently depend on the need of the tissue to 
 which they are supplied. 
 
 By feeding animals on food rich with acid salts, 
 
 * Gulstonian Lectures. Med. Times and Gazette, vol. i., p. 333, 
 1855. 
 
Chap. I] FnORGANIC CONSTITUENTS. 2T^ 
 
 Hofrniiiiiii* ami Loscarf liavc .sliown, tliat liowcvor 
 1,'ivat the toiKioiicy of uric acid and of the acid salts of 
 |>iiosplioric acid is to combine with Imscs, yet these 
 were not witlidrawn from tin; alkaline blood, but were 
 evidently withheld to maintain its alkalinity. Tlicse 
 experimental facts are borne out by what seems to 
 occur in scurvy. That disease is brought about by 
 the prolonged withdrawal of the organic acids of 
 vegetables and of recently killed meat, and their 
 salts, from the dietary of those affected. These 
 organic salts by oxydation yield alkaline carbo- 
 nates. Now the alkaline carbonates are the salts 
 I'hiefly concerned in maintaining the alkalescence of 
 the blood, and it lias been found that when these are 
 cut off" by the withdrawal of vegetable food, the 
 alkaline pliosphat(>s are not excreted in the u.sual 
 amount in the urine, but are apparently retained in 
 the bo.ly to maintain the normal alkalescence of the 
 blood, which has suffered by the withdrawal of the 
 alkaline carbonates. Dr. Gaskell,| too, has shown 
 fxperimontally that a dilute alkaline solution acts 
 upon the muscular tissue of the heart so as to produce 
 a powerful contraction, whilst a dilute acid solution 
 l)roduces an opposite effect. Variations in the alka- 
 linity of the blood, therefore, pi'obably cause dis- 
 t urbances of the circulation and so effect a secondary 
 chemical influence on nutrition as well as a direct one. 
 Dr. Kinger,§ from experiments on the action of the 
 salts of potash soda and ammonia on the frog's heart, 
 has sho\vn that they have a very varying action, 
 both as regards their power of influencing the fre- 
 quency of contraction and the value of each beat. 
 
 * " Ueber der Uebergang von freien Saurer durcli das alkalisclie 
 r.lut in den Ham ; " " Z. fiir Biologic," vii. 
 
 t " Zur alkalescence des Blutes ; " " Arcliiv fiir riiysiologie," 
 I'lliiger. 1874. 
 
 X " Journal of Physiologj'," vol. iii., No. 1. 1880. 
 
 § Med.-Cliir. Trans,, vol. Ixv., p. 191. 1882. 
 
24 Clinical Chemistry. [Chap. i. 
 
 Moreover, it has been shown that the various salts 
 introduced into the body do not pass through un- 
 altered ; probably all undergo some change. In the 
 case of sodium chloride only four-fifths of that taken 
 into the system passes out as such, the remaining fifth 
 being decomposed into acid potassium phosphate. 
 When chloride of calcium is taken by the mouth, 
 nearly the whole of the lime is found in the faeces as 
 a carbonate, whilst the whole of the chlorine is re- 
 coverable from the urine as chloride of potassium or 
 sodium. Such decompositions help us to explain the 
 seeming paradox that from the alkaline blood acid se- 
 cretions are formed. Thus, in the case of the urine I 
 have shown experimentally* that its acidity was the 
 result of the decomposition between sodium or potas- 
 sium bicarbonate and neutral sodium phosphate, two 
 salts which exist in the blood ; thus. 
 
 Bicarbonate. Neutral phosphate. Carbonate. Acid phosphate. 
 
 NaHgCOa + Na^HPO, = Na^HCOa + NaH^PO^. 
 
 And Maly,f who has investigated the subject of the 
 acidity of the gastric juice with great care, has come to 
 the conclusion that the hydrochloric acid is derived 
 from the decomposition of neutral sodium phosphate 
 with calcium chloride; thus. 
 
 Neutral sodium Calcium Tricalcic Sodium. Hydrochloric 
 
 phosphate. chloride. phosphate. chloride. acii. 
 
 Na^HPO, -I- sCaOl^ = CaaPO^ -f 4NaCl f 2HCI, 
 
 the acid in both instances diifusing out toward the 
 free surface of the secreting membrane, the other salts 
 remaining in the blood and returning to the circula- 
 tion. 
 
 * Lancet, p. 29, July 4th, 1874. 
 
 t " Zeitschrift fur Physiolog. Chimie,"p. 174. 1877. 
 
Chap. I.] Inorganic Const/tuhnts. 25 
 
 10. I>i<ii>tril»iitioii of flic iiiorijaiiic coiiNfi- 
 lii('iit«!> ill tlie (litrc'i'ciit liH<mio« iiii<l lliii<ls.— 
 
 'J'lio following table gives the percentage of inorganic 
 rosidue in tlie principal tissues and lluids of the body. 
 It nnist be rcunemljered, however, with regard to the 
 fluids, that the amounts are only approximate, since 
 they vary gi-eatly during the period of the twenty-four 
 hours, under the ditierent physiological conditions. 
 
 Takle I. — Percentage of Inougamc Resiuce in 
 
 I'.namol S)6'41 
 
 l>('ntiiie 71-30 
 
 I'.one 66-70 
 
 Muscle 1-82 
 
 Nerve 174 
 
 Trine (24 hours) . . 1-32 
 
 lUood plasma. . . . 0-82 
 
 Dlood corpuscles . . . 0-72 
 
 Pus 0-84 
 
 Chyle 83 
 
 Lvniph 0-72 
 
 Bile 0-78« 
 
 Gastric juice. ... 024 
 
 8aliva 0-18 
 
 Pancreatic juice . . — 
 
 The diflerent inorganic constituents are distri- 
 butetl in very Aarying proportions among the tissues 
 and fluids ; thus, in muscle, in 100 jiarts of the ash the 
 ])otassium salts are to the sodium salts as 58 to '2?>, 
 whilst in blood they are as 6 to 79. Again, the 
 distribution of the inorganic salts in blood is found 
 to difi'er in the ash of the plasma and corpuscles 
 i-elatively ; thus, in the ash of 1000 parts of corpuscles 
 there is 3-G79 parts of potassium chloride and 2-343 of 
 j)otassium phosphate, whilst in the serum the potas- 
 sium chloride only amounts to -408 and a mere trace 
 of potassium phosphate. On the other hand, the 
 serum is pai'ticularly rich in sodium chloride whilst 
 the corpuscles yield but little. Dr. Ringer's experi- 
 ments, already alluded to, seem to throw some light 
 on the reason for this marked divergence. The effect 
 of the potassium salts on the action of the heart, says 
 
 * The bases combined with glycocholic and taurocholic acids 
 not reckoned. 
 
26 Clinical Chemistry. [Chap. i. 
 
 Dr. Ringer, was to increase contractility and excita- 
 bility to a far greater extent than is the case with the 
 sodium salts, and therefore the former are to be 
 regarded as the most " poisonoiis " in their action, and 
 Dr. Ringer infers that " the action in one tissue being 
 selected and all other conditions being kept as far as 
 possible identical, if one salt prove itself more active 
 than another, it is at least not improbable that this 
 same salt will also prove itself more active under the 
 more complex conditions presented by the organism as 
 a whola" It can therefore be conceived that it is 
 advantageous that the sodium salts which are the least 
 active, as far as conditions of contractility and excita- 
 bility are concerned, are those which remain free in 
 the serum, whilst the most active, the potassium 
 salts, are fixed, so to speak, in the corpuscles till 
 required to play their part in the nutrition of the 
 tissues. 
 
 11. The conditions in wliich the inor- 
 g'anic constituents exist in the tissues and 
 fluids. — The inorganic constituents enter and pass 
 out of the system as crystalloids, but whilst in contact 
 ■with organic matter they seem to lose their crystalline 
 form and become colloidal, and thus give the tissues 
 and fluids their homogeneous appearance. The in- 
 fluence of colloid media upon crystalline form has 
 recently received considerable attention, and a further 
 study will, no doubt, throw considerable light on the 
 pathological changes occurring in the solid tissues, 
 owing to morbid conditions of the colloidal medium 
 itself, or to an inadequate supply of the inorganic 
 constituents themselves, or to irregular distribution 
 (excess or deficiency) of the acids and bases. Atten- 
 tion was first drawn to the subject of molecular 
 coalescence by Professor Rainej',* and his work has 
 
 * " On the Mode of Formation of Shells, of Bone, and several 
 other Structures, by a Process of Molecular Coalescence." 18.58. 
 
Cliap. I.J /a'OKCAX/C CoXS/l/UJiNiS. 27 
 
 lii-en ably followed up by Dr. W. M. Ord,* Dr. 
 A'aiulykc Cart(n-,f and Professor llarting.;}: The 
 lullowing ore .some of the most important conclu.sion.s 
 arrived at. When two saline solutions, a.s, for in- 
 stance, sodium carbonate and calcium chloride, which, 
 by double decomposition, are calculated to produce an 
 insoluble carbonate of lime, are allowed gradually and 
 .slowly to intermix, through the intervention of a 
 vi.scous medium (such as dissolved gum or albumin), 
 there are formed by the union of nascent salt with 
 colloid, not crystals of the cari)onate, but small, firm, 
 rounded bodies, which are possessed of a concentric 
 and radiate structure, and to whicli the term sub- 
 iiiurj>houii is apj)lied. These bodies, though dis^iosed 
 to adhere to any surface, connnonly remain free, Vjut 
 also exhibit a tendency to meet and blend together, so 
 as to lead to the construction of a laminar series. Tlie 
 chief conditions that influence the phenomena of 
 molecular coalescence may be thus enumerated : (1) 
 Nature of colloidal medium ; (2) nature of earthy 
 salts ; (3) temperature of the solution ; (4) density 
 of the solution ; (5) rapidity with which the saline 
 constituents intermingle. The converse of " molecu- 
 lar coalescence " is " molecular disintegration," wliich 
 Dr. Ord pronounces as the most strikingly original of 
 I'rofessor liainey's researches, and which promises to 
 bear much fruit in the elucidation of the nature of 
 certain bone diseases and the disintegi'ation of renal 
 calculi. The inorganic substances occurring in the 
 animal tissues and fluids are not, for the most part, 
 united in a true chemical combination, but form, so 
 to speak, a loose physico-chemical combination, and 
 are, as it were, held in solution, from which 
 
 * " On the Influence of Colloids upon Crj'stalline Form and 
 Cohesion." 1879. 
 
 t " IMode of Formation of Urinary Calculi." 1873. 
 
 + " Artificial Production of some of the Principal Organic 
 Calcareous Formations. "' Utreclit. 1872. 
 
28 Clinical Chemistry. [Chap. ii. 
 
 they can be removed by mechanical means. Thus, 
 for example, if some tissue, as muscle, be minced 
 very fine and placed in a dialyser, and the dia- 
 lyser floated in water, after the lapse of some 
 hours the flesh will lose its consistence and become 
 pulpy and jelly-like, at the same time the water 
 will increase in density from the diffusion of the 
 inorganic salts iiito it ; and these salts can be obtained 
 for analysis by evaporating the diffusate. This pro- 
 cess of diffusion is the best method for ascertaining 
 the nature and chemical composition of salts as they 
 exist in the tissues and fluids, since the result obtained 
 by incineration is an artificial one, and does not 
 represent the composition of the inorganic constituents 
 as they exist in a natural condition in the tissues ; 
 since in burning off the organic matter the phos- 
 phorus and sulphur, which exist in proteid substances, 
 become oxydised and form phosphates and sulphates. 
 By applying the process of dialysis as a means of 
 investigation to the exact constitution of inorganic 
 constituents as they exist in the tissues, R. Maly * 
 has arrived at very important results, one of the chief 
 being the exact nature and composition of the saline 
 constituents of the blood. 
 
 CHAPTER II. 
 
 Section A. — Enumeration op the Chief Organic 
 Constituents of the Animal Body. 
 
 division i. saccharine and starchy principles. 
 
 All contain six atoms (or multiples of six) of carbon, 
 are generally known as carbohydrates. Bertholet has 
 shoAvn that these substances are alcohols, or are related 
 * Op. cit. 
 
Chap. II. J S.lCCHAKIA'l-: PRlNC/rLf-iS. 29 
 
 to tlic alcohols, of tlic liii^hor polyatomic radicals (§ 5). 
 They clo.sely resoinblo one another in their chemical 
 characters and are Isomeric, are neutral in their 
 reaction, and have little disposition to enter into 
 combination. They have all a strong action on 
 polarised light. They are divisible into three groups. 
 
 Group I. Glucoses n(CBHi208). 
 
 12. Oliicosc C,iH|._,0,i (syn. cbxtrose, grape sugar). 
 — In jiure state crystallises in rhombic tablets, but ig 
 usually met with in irregular warty masses. Soluble 
 in own weight of cold water, the solution gives a 
 dextro-rotatory power + 57-6°. Undergoes vinous 
 fermentation when yeast is added. Albu7iiinons 
 ferments induce lactic and subsequently butyric acid 
 fermentation. Solutions of grape sugar become brown 
 when boiled with liquor potassse, and picric acid 
 added to such solution gives a deep mahogany red. 
 Alkaline solutions when heated reduce cupric salts, 
 throwing down retl precij^itate of oxide of copper. An 
 alkaline solution, heated with a few granules of 
 bi.smuth, reduces the latter, and turns it black. A 
 solution made faintly alkaline with sodic carbonate, 
 and renderetl blue l)y the addition of indigo, when 
 heated to boiling, without agitation, becomes first violet, 
 then yellow ; on agitation the blue colour is restored. 
 
 LfSevulose C^H|oO,j (syn. invert sugar). — 
 Incapable of crystallisation. Exists as a syrupy 
 residue. Does not ferment so readily as grape sugar, 
 but reduces copper from alkaline solutions readily. 
 DiO'ers from gi-ape sugar in its left-handed polarisation, 
 which diminishes as temperature rises; being- lOG^at 
 15° C.,-7y-o° at 52° C, and -53° at 90° 0. 
 
 Inositc CgHjoOg + 2H._,0 (syn. muscle sttgar). — 
 Crystallises in two forms: (1) Large rhombic tables ; 
 (2) small tufted groups of oblique ])risms. Soluble 
 in six parts of water at 20*^ C, insoluble in alcohol 
 
30 . Clinical Chemistry. [Chap. ir. 
 
 and ether, unfermentable with yeast, no action on 
 polarised light ; alkaline solutions do not reduce salts 
 of copper, but give a greenish tint which clears up on 
 standing, leaving original blue solution, but which 
 again becomes green on heating. Heated to dryness 
 on platinuna foil, with a drop of nitric acid, the 
 residue moistened with ammonia and calcium chloride 
 yields a beautiful rose colour. 
 
 Group II. Saccharoses n(Ci2H220ii). 
 
 13. Saccharose CjsHgaOn (syn. cane sugar). — 
 Crystals, monoclinic prisms, very soluble in water, 
 insoluble in absolute alcohol and water. Solutions 
 have a dextro-rotatory power + 73 -S*^, Boiled with 
 water for some hours it is converted into a mixture of 
 glucose and la^vulose, or ^'■invert sugai:" It ferments 
 with yeast, but is transformed first into glucose. Does 
 not at fii'st reduce cupric salts from alkaline solutions, 
 but does so after a while. In the intestines cane 
 sugar is converted into " invert " sugar. 
 
 Lactose Qy^.^^O^^-\-H^O (syn. milk sugar). — 
 Crystals rhombic, soluble in six parts of cold water ; 
 dextro-rotatory power = + 59'3°. Does not readily 
 undergo vinous fermentation ; reduces copper in 
 alkaline solutions. Boiled for some hours with dilute 
 acids, forms galactose, this treated with nitric acid 
 yields mucic acid. 
 
 Group III. Amyloses n(CeHio05). 
 
 14. Amylum CgHioOg (syn. starch). — Granules, 
 rounded, irregular form, marked with concentric 
 laminse, having a hilum or pore on surface. Insoluble 
 in cold water, but when boiled swell up, burst, and 
 form paste or mucilage. Solution is dextro-gyrous 
 
 -f- 2 1 6°. With iodine, starch solutions give a deep blue 
 colour, which it loses when heated to 100° C, but 
 I'egains it on cooling. Diastase, dilute sulphuric acid. 
 
Chap. II.] /■ATT)- PrISXIPLTS. 3 I 
 
 the salivary and pancreatic ferments, convert starch 
 into glucose and dextrin. The further action of 
 saliva is probably to convert the dextrin into glucose 
 by the assumption of water, thus : 
 
 starch. Water. Glucose. Dpxtrin. 
 
 sCeH.oO^ + H,0 = C«H,A + 2aH„0, 
 and 
 
 Dextrin. Water. Glucose. 
 
 2CeH,o05 + 2ILO = 2C«H,A- 
 
 Dextrin C^HioOs (syn. British <fum). — A yel- 
 lowish powder, soluble in water, forming a viscous 
 lluid. Solutions dextro-gyi'ous — -f 138'8°. Witli 
 iodine gives reddish colour, which disappears on 
 heating and does not reappear. Does not undergo 
 vinous fermentation, or reduce copper salts till con- 
 verted into glucose. 
 
 Olycogeu C^HioOg (syn. animal starch). — Yel- 
 lowish-white amorphous substance. Soluble in cold 
 water, insoluble in alcohol. Readily converted into 
 glucose. "With iodine gives a similar coloration as 
 dextrin, but is distinguished from it by the colour 
 reappearing after it had been lost by heating. 
 
 DIVISION II. THE FATTY PRINCIPLES. 
 
 The natural oils and fata existing in the body are 
 all compounds of glycerin with fatty acids ; the chief of 
 which are mixtures of stearic, palmitic, and oleic acids. 
 Thus, the tri-stearin of suet consists of three parts 
 of the radical, stearyl CigHsjO, which has replaced three 
 atoms of typical hydrogen from glycerin C3H5 (0H)3 
 
 thus, /p tt'o\ f ^3- They are neutral bodies, of 
 
 soft greasy consistence, highly inflammable. Insoluble 
 in water. Soluble in ether, benzol, fluid oils, carbon 
 
32 Clinical Chemistry. [Chap. ii. 
 
 bisulphide, chloroform, and hot alcohol. Heated with 
 alkalies, they are saponified; that is, the fatty acid 
 unites with the alkali to form a soap, whilst the 
 glycerin is set free. Oils and melted fats, shaken iip 
 with water containing albumin, bile, pancreatin, etc., 
 become emulsionised ; that is, the fatty matter is 
 broken up into small globules, which become more or 
 less permanently suspended in the aqueous solution. 
 
 15. Stearin CsyH^oOg (syn. tri-stearin). — The 
 chief constituent of solid fat. Occurs in white crystal- 
 line nodules. Melting point variable ; 65° 0. to 
 69"7° C. (Heintz). Soluble in boiling alcohol, from 
 which large square scales of stearin are deposited on 
 cooling. 
 
 16. Palmitin CsiHggOg (syn. tri-palmitin). — 
 Fine needle-shaped crystals. Melting point variable ; 
 mean 62-8'' 0. (Heintz). The substance known as 
 margarin consists of ten per cent, of stearin and 
 ninety per cent, of palmitin. Margarin is obtained 
 by heating fat in a water-bath, stirring with an equal 
 quantity of alcohol. The alcoholic solution on cooling 
 deposits needle-shaped crystals, arranged in whorled 
 groups or feathers. The melting-point of margarin is 
 lower than the melting-point of its two constituents, 
 being 47-8° 0. (Heintz). 
 
 17. Olein G^jfl-^Qfie (syn. tri-olein). — Colourless 
 oil, remaining liquid at 0° 0. ; exposed to air, it absorbs 
 oxygen, and becomes rancid. Heated to 280° C, it is 
 decomposed, and yields sebacic acid. 
 
 18. Olycerin C3H5(OH)3. — Colourless syrupy 
 liquid. Soluble in water and in alcohol. Heated 
 with fatty acids, it combines with them, forming ethers 
 (glycerides) which constitute the neutral fats. 
 
 19. Olycerin - phosphoric acid CsHgPOg. — 
 Syrupy liquid, both sour and sweet to taste. It is 
 dibasic, and its barium and calcium salts are soluble 
 in cold water, but not in alcohol. Its chief interest 
 
Chap. II.] l'hor[-,iD Principles. 33 
 
 is its association with a group of phosphorised bodies, 
 of which lecitliiu is the chief. 
 
 DIVISION III. — rROTKID PRINCIPLES. 
 
 Those constitute tlie basis of all the tissues of the 
 Itody. They are amorphous, have low diil'usive powers, 
 turn the plane of polarisation to the left. Heated 
 with caustic alkalies, they give ofl' auinionia, volatile 
 fatty acids as formic, acetic, etc., and yield leucin, 
 tyrosin, and glycocin. Heated with strong nitric acid, 
 tliey give a yellow colour, which turns orange on tlie 
 addition of ammonia {xantJio-proteic reaction). Boiled 
 with mercuiic nitrate solution, a red colour i.^ deve- 
 loped (Mil/un's reaction). With acetic acid and ferro- 
 cyanide of potas.sium, proteids are precipitated from 
 their solutions. Also by picric acid, tannic acid, or 
 mercuric chloride. Acted upon by the gastric and 
 pancreatic ferments they all become soluble, and 
 acquire greater diffusive power. 
 
 Group I. Native albuinins. — Soluble in pure 
 water. 
 
 20. Soriiin albiiiiiiii. — Viscid glairy fluid. 
 Neutral in reaction, freely soluble in pure water. Its so- 
 lutions have a spcciiic rotatory power of - 56° C. When 
 heated the solutions become ojiaque at 62'65° C, and 
 coagulation occurs at 73' C. Strong mineral acids also 
 produce coagulation, but they are not precipitated by 
 sodium chloride, organic acids, nor dilute mineral acids. 
 
 £gg albumin diflers fi'om the above in that it is 
 coagulated by ether, whilst serum albumin is not, and 
 that the specific rotatory power for light is - 35 'S" C, 
 instead of — 50" C. 
 
 Group II. Globulins. — Not soluble in pure 
 water, but in dilute neutral saline solutions. 
 
 21. Olobuliii (syn. crystallin). — As deposited 
 iu its coagulated form, by passing a current of carbonic 
 
 D 
 
34 Clinical Chemistry. [Chap. ii. 
 
 acid througli its aqueous solution, globulin is insoluble 
 in pure water, but undergoes solution if the water is 
 saturated with oxygen. It is also soluble in dilute 
 neutral saline solutions. Solutions of globulin become 
 opalescent when heated to 73° C, and globulin is 
 deposited at 93° C. Globulin is precipitated from its 
 solutions by carbonic acid gas and by alcohol. (Con- 
 stitxient of aqueous and vitreous humours of eye.) 
 
 Paraglohulin (syn. serum globulin, Jlbrinoplastic). 
 — As precij)itated from blood serum by complete 
 saturation with magnesium sulphate, paraglobulin 
 is soluble in water saturated with oxygen, in dilute 
 neutral saline solutions (very dilute solution of 
 common salt, 0'5 per cent., precipitates paraglobulin 
 from solution; on addition of more salt the precipitate 
 redissolves, till about 20 per cent, is added, when 
 precipitate recurs), and in weak solutions of alkaline 
 carbonate, from which it is precipitated by alcohol. 
 Solutions coagulate at 75° C, but vary considerably, 
 according to amount of saline substance present in 
 solution. (Constituent of blood serum, and plasma, 
 colourless corpuscles of lymph and chyle.) 
 
 Fibrinogen. — As obtained from blood by mixing 
 one-third its volume with saturated solution of mag- 
 nesium sulphate, filtering and precipitating filtrate 
 with saturated solution of common salt ; removing the 
 flaky precipitate, and frequently redissolving and re- 
 precipitating by alternately using solutions of common 
 salt of 7 per cent, and 20 per cent., to render it quite 
 free from paraglobulin. After the last precipitation, 
 dissolve in cold water, in which, owing to the salt 
 adhering to the precipitate, it is soluble. This solu-. 
 tion coagulates at from 52° 0. to 56° C. ; when serum 
 or a solution containing fibrin ferment is added, fibrin 
 is formed. (Constituents of blood serum, serous fluids, 
 and many pathological transudations.) The fibrin 
 ferment is prepared by adding to blood serum twenty 
 
Chap. II.] Pi^OTEiD Principles. 35 
 
 times its voIuiih^ of alcoliol, and allowing to digest 
 for a month or more. Tlie insoluble matter is removed 
 and agitated with water and tlie mixture filtered. 
 The precipitate is then dried over snli)huric acid and 
 iinely pulverised. The aqueous solution, added to a 
 solution containing fil)rino[»lastic and fibrinogen, causes 
 immediate coagulation. 
 
 Hannorilohin. — Crystals of oxy-htemoglobin are 
 rhombic plates or prisms with dihedral summits freely 
 soluble in water, insoluble in alcohol, ether, or chloro- 
 form. Solutions of oxy-ha-moglobin rendered suffi- 
 ciently dilute, give two absorption bands in the spec- 
 trum in the yellow and beginning of green between D 
 and E, the band nearest D being tlie smaller and darker. 
 If to this solution we add annnoniacal stannous cldo- 
 ride, to which enough tartaric acid has been added to pre- 
 vent precipitation, the two bands fade away, and there 
 appears a single broad band situated almost between 
 the two preceding ones. This is the band of reduced 
 hajmoglobin. Solutions of haemoglobin readily decom- 
 pose at temperatures above 0° C. ; on the addition of 
 acids and caustic alkalies, they break up into hcematin 
 and globulin ; treated with glacial acetic acid and any 
 metallic chloride, it is decomposed into hcemin. Other 
 products of its decomposition ai'e hcematoidin, hcemo- 
 chromogen, Jicematopopphyrin. 
 
 22. Myosin. — As prepared by washing finely- 
 minced muscle with cold water till a precipitate is no 
 longer thrown down on the addition of mercuric chlo- 
 ride. The residue on filter is then treated with 10 per 
 cent, solution of sodium chloride, strained through 
 linen, the resulting liquid filtered and precipitated by 
 the addition of distilled water. In this state it is in- 
 soluble in pure water, but is so in very dilute saline 
 solutions (I per cent.); from these it is precipitated 
 by the addition of common salt in bulk. Coagulates 
 at 70° C. 
 
36 Clinical Chemistry. [Chap. 11. 
 
 23. Group III. Fibrin. — Insoluble in water, and 
 in dilute saline solutions. Does not dissolve in 1 per 
 cent, solutions of hydrochloric acid, but swells up ; 
 pepsin added to this solution makes the fibrin soluble. 
 Fibrin has the power of decomposing hydrogen 
 peroxide, and giving a blue reaction with guiacum 
 and etheiial solution of hydrogen peroxide. 
 
 Group IV. Modified albiunins. — Insoluble in 
 water and dilute saline solutions, but soluble in dilute 
 acids and alkali. 
 
 24. Acid albumin (syntonin). — Obtained by gradu- 
 ally heating a solution containing albumin with a 
 dilute acid (1 per cent, solution of strong HlC), 
 reprecipitated by neutralisation, but the precipitate 
 is soluble in excess of the reagent. Its very dilute acid 
 solution possesses a Isevo-rotatory power of — 72°. 
 
 Alkali albumin [casein). — Obtained by heating 
 solutions of albumin with dilute alkalies, reprecipitated 
 on neutralisation, insoluble in excess, or in the presence 
 of alkaline phosphates. The Isevo-rotatory power of 
 its alkaline solution prepared from sero-albumin is 
 — 86°, from egg albumin —47°. 
 
 25. Group V. Peptones. — Soluble in water, 
 not coagulable by heat. Very diffusible, and pass easily 
 through animal membranes. With an alkaline solution 
 of cupric sulphate give a rosy red colour. Precipi- 
 tated by picric acid, which is redissolved when warmed. 
 
 Group VI, Albuminoids or allied albumins, 
 resembling in many points the proteids above de- 
 scribed in chemical constitution, but exhibit in their 
 characteristic reactions considerable difierences among 
 themselves. They occur in the epithelial and con- 
 nective tissues. 
 
 26. Mucin. — Insoluble in cold water, but freely 
 soluble in alkaline solutions, from which it is precipi- 
 tated in strong masses by acetic acid, the precipitate 
 not being dissolved by sodium sulphate ; precipitated 
 
Chap. II.] Products OF Metabolism. 37 
 
 by alcohol and alum, soluble in excess of the latter. 
 Its solutions are not precipitated by heat or mercuric 
 chloride, or potassium ferrucyanide and acetic acid. 
 
 27. Golafin. — Insoluble in cold water, but 
 freely soluble in hot, fjelatinidng when cold. It is not 
 precipitated by acetic acid, but l)y mercuric chloride. 
 Boiling with acids, or even prolonged boiling, prevents 
 its warm solution (jelatinisiug when cold. 
 
 28. Chondrin. — Soluble in hot water, gelatin- 
 ising when cold, precipitated by acetic acid, but the 
 precipitate is dissolved by sodium sul[)hate. Alum 
 precipitates chondrin in excess. 
 
 29. Elasficiii. — Highly insoluble, even at high 
 temperature, its hot solution does not gelatinise on 
 cooling, gives no precipitate with acetic acid. 
 
 30. Lardacein. — Insoluble in water and in 
 dilute saline solutions. Not acted on by gastric juice. 
 Gives a mahogany tinge when treated by iodine, and 
 rosy red by methylanilin. 
 
 Section II. — Products of Metabolism. 
 
 These are the products of oxydation of the non- 
 nitrogenous and nitrogenous constituents, substances 
 which enter into the composition of the body, and 
 whose reactions have been discussed in the preceding 
 sections of this chapter. The non-nitrogenous group 
 consists chiefly of acids belonging to the fatty acid 
 series, the aromatic groups and resinous acid, with 
 some of their alcohols or aldehydes. The nitrogenous 
 bases, or amides, are derived from the metabolism of 
 the albuminous principles. 
 
 DIVISIOX I. NOX-XITROGEKOUS. 
 
 Group I. Fatty acids. — Derived from the oxyda- 
 tion of the corresponding alcohols of the homologous 
 
38 Clinical Chemistry. [Chap. 11. 
 
 series of hydrocarbon radicals, they are arranged in 
 classes according as they are formed by monatomic or 
 diatomic radicals. 
 
 Class I. Monatomic fatty acids. — The acids 
 in this list are derived from the monatomic series of 
 homologous hydrocarbons by the oxydation of the 
 corresponding alcohols in which one atom of oxygen 
 replaces two atoms of hydrogen; thus ethyl alcohol by 
 oxydation loses two atoms of hydrogen, and is con- 
 nected into aldehyde ; and aldehyde by further oxyda- 
 tion becomes acetic acid ; thus, 
 
 Ethyl alcohol. Aldehyde. 
 
 C^HgO + O = O^H.O - H^O 
 
 Aldehyde. Acetic acid. 
 
 C,H,0 + O = O^H.O^- 
 
 31. Formic acid CH2O2. — Is a colourless corro- 
 sive liquid, boiling point 100° 0., solid at 1° 0. 
 
 32. Acetic acid CgH^Oy — Is a colourless sharp- 
 smelling liquid ; boiling point 118° C, solid at 17° C. 
 
 Acetone. — Limpid, colourless liquid, sp. gr. 0"7921, 
 with a peculiar etherial (decayed apple) odour. Solu- 
 tions of acetone give violet-red, with ferric chloride ; 
 with iodine and chlorine in the presence and alkalies 
 it is converted into iodoform and chloroform. 
 
 Alcohol. — Heated with a few drops of sul- 
 phuric acid and solution of potassium dichromate, an 
 emerald green colour is produced. Nitric acid added 
 to alcohol, and this mixture warmed, gives off fumes 
 of nitrous ether ; if to this a solution of mercurous 
 nitrate be added and heat applied, a yellowish 
 precipitate will be thrown down ; this is mercuric 
 fulminate. A solution of alcohol heated with potas- 
 sium hydrate and iodine gives a yellow precipitate of 
 iodoform. 
 
ciuip. ii.j Fatty Acids. 39 
 
 33. Propionic acid CaHaOy — Is a colourless 
 oily lifiuid ; boilini,' ]ioint 140" C, solid at 20° C. 
 
 34. Btityi'ic acitl Q^jd.,. — Is a mobile colour- 
 less liquid ; boiling point 102° C, solid at 20° C. ; odour 
 of rancid butter ; by feruKaitation lactic acid yields 
 butyric acid, carbonic acid, and hydrogen. 
 
 35. Valeric acid CjIIioOn. — Is a limpid, colour- 
 less, oily liquid ; boiling point 174° C, solid at 20° C. ; 
 odour of valeiian. 
 
 36. Caproic acid CoHioOo. — An oily liquid 
 having the odour of acid sweat; boiling point 199° C, 
 solid at 4° C. 
 
 37. Capric acid Q,^^^^ — Is a greasy oily liquid, 
 which crystallises at 29° C. in colourless needles, 
 which on heating evolve a goaty odour ; boiling point 
 236° C. 
 
 38. Palmitic acid C10H30O2. — Is a tasteless, 
 white, fatty substance ; melting point 62° C, soluble 
 in ether and alcohol, forming acid solutions which on 
 concentration deposit white crystalline needles ; in- 
 soluble in water. With glycerin it forms three bases 
 (glycerides) : (1) mono-palmatin, (2) di-palmitin, and 
 (3) ti'i-palmitin ; the latter is a constituent of animal 
 fat, which mixed with tri-stearin forms margarin. 
 
 39. Stearic acid Q,^^.Jd.,. — Is a white crys- 
 talline substance ; melting point 69"2° C, soluble in 
 ether and alcohol, insoluble in water. Like palmitic 
 acid, it forms with glycerin three compounds, mono- 
 stearin, di-stearin, and tri-stearin ; the latter is a con- 
 stituent of suet. 
 
 40. Oleic acid CigHsiO,- — Is solid at 4° C, 
 liquid at 14° C. ; freely soluble in alcohol and ether, in- 
 soluble in water. By the action of nitrous acid it is 
 convei'ted into elaidic acid. By distillation it yields 
 sebacic acid ; this distinguishes it from other fatty 
 acids. With glycerin it forms mon-olein, di-olein, and 
 tri-olein ; the latter forms the oily portion of the animal 
 
40 Clinical Chemistry. [Chap. ii. 
 
 fat. Oleic acid is in reality derived from tlie glycerin 
 series of homologous hydrocarbons, but for conve- 
 nience is classified here. 
 
 Class II. Diatomic fatty acids. — These acids 
 are derived from the " olefine series of homologous 
 hydrocarbons" by the oxydation of the corresjDonding 
 alcohols, and may be diAdded into two classes, viz., 
 the monobasic acids which are formed by one atom of 
 oxygen replacing two atoms of hydrogen in the corre- 
 sponding alcohol ; and the dibasic acids which are 
 formed by the replacement of four atoms of hydrogen 
 by two atoms of oxygen ; thus ethylene alcohol by 
 oxydation loses two atoms of hydrogen, and is con- 
 verted into monobasic glycollic acid ; and glycollic 
 acid by further oxydation loses two atoms of hydrogen 
 and becomes dibasic oxalic acid, thus : 
 
 Ethylene alcohol. Glycollic acid. 
 
 C,HeO, + O, = H,0 + C,H,03 
 
 Glycollic acid. Oxalic acid. 
 
 C2H4O3 + O2 =-- H.O + C2H2O,. 
 
 Sub-Class (a) — Monobasic Acids. 
 
 41. Cartooiiic acid CH2O3. — Colourless in- 
 odorous gas. Specific gravity 1-529 heavier than gas, 
 soluble in an equal volume of water. This solution 
 reddens blue litmus paper, the red colour disappears on 
 drying. Carbonic acid gas passed thi'ough lime water 
 produces a white precipitate of calcium carbonate. It 
 is best determined quantitatively by passing it through 
 a solution of potassium hydrate and noting increase of 
 weight in the solution, or by the process given for 
 estimation of carbonates. 
 
 42. Cclycollic acid CgH^Og. — This substance 
 does not exist in a free state in the organism. Its 
 ammoniated form, glycocin, conjugated with cholic 
 
ch.np. 11.] Fatty Acids. 41 
 
 acid, forms the glycocholic acid of the bile ; and with 
 benzoic acid luiites to form Ijippuric acid. Glycollic 
 acid is a syrupy acid liquid, soluble in ether and alcohol, 
 from concentrated solutions of which deliquescent 
 crystals, which uiclt at 78° C, are deposited. 
 
 43. L.aclic acid C-jHuO,... — Is a colourless syrupy 
 (luid of sharp acid taste; .specific gravity 1-21; soluble 
 in water, alcohol, and etlier. If distilled at temper- 
 atures above 160° C, it decomposes. Heated with 
 sulphuric acid it evolves carbonic oxide. Heated with 
 nitric acid it j-ields oxalic oxide. Its calcium and zinc 
 salts- are characteristic. Sarcolactic acid (paralactic 
 and ethylene lactic acids) closely resembles lactic acid 
 and is isomeric with it ; its salts, however, differ in 
 crystallising with a smaller proportion of water, and 
 in their crystalline form ; it is obtained from muscular 
 tissue. 
 
 46, Licucic acid Q^^.f).^. — This acid only exists 
 in the body in its ammoniated form, leucin, from 
 wjiich it can be obtained by heating with nitrous acid. 
 [See Leucin.) 
 
 Sub-Class {h) — Dibasic Acids. 
 
 47. Oxalic acid C^HjOj. — Crystallises in 
 pnsms ; its solutions have an intensely sour taste. 
 Heated to 160° C, oxalic acid is partially decomposed 
 into formic acid, carbonic acid, and water. With 
 solutions of lime it forms the normal calcium oxalate, 
 a highly insoluble salt, which is deposited from urine 
 usually in the form of octohedral crystals of letter- 
 envelope shape. Solutions of calcium oxalate are 
 precipitated by the addition of alcohol. "With silver 
 uitrate they give a white precipitate, soluble in nitric 
 acid and ammonia ; if the precipitate be greatly 
 lieated on platinum foil it will decrepitate, leaving a 
 residue of inctallic silver. 
 
42 Clinical Chemistry. [Chap. ii. 
 
 48. Succinic acid C^HgO^. — The crystals form 
 large rhombic colourless tablets which fuse at 160° C, 
 and are soluble in alcohol and cold water. These 
 solutions give a brown precipitate with ferric chloride, 
 and white with barium chloride. Found sometimes in 
 hydrocele fluids and contents of ovarian cysts. 
 
 Group II. — Aromatic acid series. 
 
 49. Benzoic acid CyHgOg. — Occurs in pearly 
 white crystalline plates, which fuse at 121° C Its 
 solutions give reddish-brown precipitates with ferric 
 chloride, and blue precipitates with cupric acetate. 
 Found sometimes in stale human urine, is present in 
 the fresh urine of herbivorous animals. Its chief 
 interest is due to the presence of its radical in 
 hippuric acid. 
 
 50. Carbolic acid CgHgO (syn. phenol). — 
 Occurs as a white crystalline mass, melting at 42° C, 
 and forming a heavy, oily, corrosive fluid with a pi;n- 
 gent, smoky odour. It gives a violet colour to solutions 
 of ferric chloride, which acquires a blue colour on 
 exposure to the air ; a chip of fir wood saturated with 
 phenylic acid and dipped into dilute hydrochloric acid 
 turns a deep blue colour. In carbolic acid poisoning 
 the sulphates disappear from the urine, being converted 
 into sulpho-carbolates. Allied to carbolic acid; 
 taurylic, damalitric, and damolic acids are to be found 
 in minute quantities in human urine. 
 
 Group III. Resinous acids. — The radical of 
 these acids has not been isolated, but it is probable 
 that it belongs to some of the higher aromatic hydro- 
 carbons. 
 
 51. Cholesteric acid CgHioOj. — Is formed when- 
 ever cholesterin is heated with nitric acid. It is 
 a yellow, non-crystallisable substance, which rapidly 
 absorbs moisture from the air ; it is soluble in water, 
 alcohol, and ether. Cholesterin 0.2^11^0 may be 
 
Chap. II. J Nitrogenous Bases. 43 
 
 rt'garded a.s an alcohol of this series, being liomologons 
 to cinnyl alcohol. As obtained from its hot alcoholic 
 solutions it forms characteristic glistening rhombic 
 plates with notched edges, which float on water ; 
 extremely soluble in ether. Heated with nitric acid 
 it gives oif yellow acid fumes of cholesteric acid ; the 
 residue touched with annnonia gives a red colora- 
 tion. Cholcsterin may be mistaken for leucin, but 
 is distinguished from that body by its solubility in 
 ether. 
 
 52. Cliolic acid Co,H,y05. — Occurs in two 
 forms, the amorphous and the crystalline. The former 
 is resinous and viscous, very slightly soluble in water, 
 but freely soluble in alcohol and caustic alkalies. In 
 the latter the crystals are octohedral and tetra- 
 hedral ; they are colourless, insoluble in water, very 
 soluble in ether and alcohol ; the octohedral variety 
 contains 1 molecule, the tetrahedral 2^ molecules of 
 water; when heated they lose this water of crystallisa- 
 tion and become disintegrated. Cholic acid heated 
 with acids at a temperature of 200° C. loses 2 atoms 
 of water and is converted into dyslysin (so named 
 from its insolubility in water), acids, alkalies, and 
 ^dcohol. Cholic acid with a solution of sulphuric acid 
 and sugar gives a deep purple coloration known as 
 Pettenkoffer's test. Conjugated with glycocin and 
 taurin it forms the bile acids glycocholic and tauro- 
 cholic acids. 
 
 DIVISION II. NITROGENOUS. 
 
 Group I. Moiiaiiiides. 
 
 53. Olycocin C^H^NOo, or amido- acetic acid. 
 Crystals of glycocin are hard and granular, and have 
 a sweet, mawkish taste ; they are soluble in 400 parts 
 of cold water, but quite insoluble in alcohol. A 
 
44 Clinical Chemistry. [Chap. ii. 
 
 transient fiery red colour is given when glycocin is 
 heated with a strong solution of caustic potash. A 
 stream of nitrous acid passed through an aqueous 
 solution of glycocin decomposes it, nitrogen is evolved, 
 and on agitating with ether and evaporating glycoUic 
 acid is obtained. Glycocin is derived from the 
 decomposition of the gelatinous tissues ; conjugated 
 with cholic acid it forms glycocliolic acid, one of the 
 acids of the bile. This acid is deposited from its 
 alcoholic solution in long delicate colourless needles, 
 slightly soluble in cold water and ether, very soluble 
 in alcohol and boiling water. These solutions are 
 precipitated by neutral lead acetate ; with strong 
 bulphuric acid and sugar they give a red coloration 
 (PettenkofFer's test). 
 
 54 Taui'in 02117X803, or ethyl amido - sul- 
 phuric acid, is prepared from bile. The crystals are 
 four-sided prisms with pyramidal extremities, insoluble 
 in ether and alcohol, soluble in 15 parts of cold water; 
 the aqueous solution has a neutral reaction. They are 
 dissolved by the mineral acids without change ; burned 
 in air they evolve sulphurous acid fumes; heated with 
 potash, ammonia is evolved, and potassiu^m sulphate 
 formed. The aqueous solutions are not precipitated 
 by salts of mercury, copper, or silver. This substance 
 is found in the bile associated with cholic acid ; it 
 can be obtained from most glandular tissues, and from 
 the lung tissue and muscular fibre of the heart. 
 Taurocholic acid never occurs in a crystalline form, 
 but appears as an oily resinous fluid, of tawny colour, 
 very soluble in alcohol and ether, and has a strong 
 acid reaction ; its aqueous solution, on heating, is 
 readily decomposed into taurin and cholic acid ; it 
 turns the plane of polarised light to the right, and 
 gives the purple reaction with sulphuric acid and cane 
 sugar. Its solutions are precipitated by basic lead 
 acetate. 
 
ciKip. II.] Njtrocea'ous Basks. 45 
 
 55. Sarcosiii CgH-NO.,, or nietliyl glycociu, con- 
 tains one atom of glycollic acid radical CjHjOv, and 
 one atom of methyl OH, replacing two atoms of II. 
 It is not met with in the animal body, its only interest 
 being that it is a constituent of kreatin, that body 
 yielding by decomposition both urea and sarcosin. 
 
 Kreatiu. Urea. Sarco.sin. 
 
 C,HoN302 + H.O -= CH.N.O + CsHjNO^. 
 
 bQ. Cholin C,-H,5N02 (syn. neurin) may be re- 
 garded as ammonium hydrate in which 1 atom of H 
 is replaced by 1 atom of oxy-ethyl C^HjO + 3 atoms of 
 
 methyl 3CH3 making /prr'x \ ^H-O. Cholin is ob- 
 tainable as a thick syrup, and has a powerful alkaline 
 reaction ; soluble in water and alcohol. Its solution 
 prevents the coagulation of albumin. It does not 
 exist free in the body, but is a constituent of leci- 
 thin, protagon, and cerebrin. 
 
 57. Cysfiii CsH-NSOj, or amido-sulpho-pyruvic 
 acid, an amide of the lactic acid series, pyruvic acid 
 l)eing lactic acid deprived of 2 atoms of hydrogen. 
 Deposited from an ammoniacal solution, it forms 
 hexagonal crystals, which have a tendency to overlap, 
 and whicli acquire a. yellowish-green tinge on exposure 
 to air. They are soluble in alkalies and strong minei'al 
 acids. Boiled with caustic potash in the presence 
 of lead acetate they yield a black precipitate of lead 
 sulphide. 
 
 58. Lieucin CgHigNOo, or amido - caproic acid. 
 — The leucic acid radical CgHuO replacing one atom 
 
 of H in ammonium hydrate; thus "-vi-tt [■ 0. Leucin 
 
 is deposited from its hot alcoholic solution in white 
 shining plates. Slightly soluble in cold alcohol ; 
 very insoluble in ether, which distinguishes it from 
 
46 Clinical Chemistry. [Chap. ii. 
 
 cliolesterin, which it closely resembles in appearance, 
 Yery soluble in boiling water. Leucin is interesting 
 physiologically as being one of the antecedents 
 of urea, and pathologically from its presence in the 
 urine in certain diseases of the liver. 
 
 59. Tyi'osin CgHnNOg is probably amido- 
 propionic acid Qi^^QS.^^Q^ in which 1 atom of H is 
 
 C3H, I 
 replaced by oxy-phenol CeHgO to make CgHjO V Oj. 
 
 nhJ 
 
 The crystals are fine needles, which sometimes cluster 
 to form stellate groups, or packs to form rounded 
 balls. They are sparingly soluble in cold water and 
 alcohol ; soluble in boiling water and in acid and 
 alkaline solutions. War-med with strong nitric acid 
 they become yellow ; the residue, if touched with 
 hydrochloric acid, becomes red, if with ammonia, brown. 
 Millon's reagent (mercuric and mercurous nitrate) gives 
 a red coloration resembling that given by proteid 
 with the same reagent. Ty rosin, when it appears in 
 the urine, is always associated with leucin, though this 
 latter body may be present without tyrosin. It is 
 found in small quantities in the spleen and pancreas, 
 and is one of the products of the action of tryjDsin on 
 albuminous matters. 
 
 60. Hippiu'ic acid CgHgNOg, or benzyl amido- 
 acetic acid, containing radicals of benzoyl and glycocol, 
 and may be written thus 0^1150(0^114)^03. The crystals 
 are semitransparent rhombic prisms ; almost insoluble 
 in cold water and ether, soluble in boiling water and 
 solution of sodium phosphate. Boiled with strong 
 hydrochloric acid it is decomposed into glycocin and 
 benzoic acid. Hippuric acid is monobasic and gives 
 buff- coloured precipitates with ferric salts. It 
 occurs as a minute normal constituent of human 
 urine, and in larger quantities among herbivorous 
 animals. 
 
Chap. II.] N/TROGENOUS Bases. 47 
 
 61. Liecifliin C^iITj^iNPOb is an amorphous waxy 
 substance, very liysroscopic ; soluble in ether and 
 alcohol, is procipitattMl from the so'ution by platinic 
 chloride with excess of alcohol. Lecithin is decom- 
 posed by boiliniij with alkalies into glycerin-phosphoric 
 acid, stearic acid, and cholin. Frotm/on has been con- 
 sidered as a mi.Kture of lecithin and cerebrin, but 
 the recent researches of Gamgee seem to show that 
 it is a definite chemical body ; he gives the formula 
 CuinH-ji^^NsPOs^. Cerebrin is a nitrogenous body free 
 from phosphorus. Some doubt still exists as to its 
 composition. According to Gaingee, protagon, which 
 cannot be separated by the action of solvents into a 
 non-phosphorised cerebrin and a phosphorised body, 
 can, however, by the action of caustic baryta be made 
 to yield non-phosphorised bodies. 
 
 Group II. Diamides. 
 
 62. Urea CH^NoO, or carbamide, and may be 
 
 CO" ) ' 
 represented as H J- N,, in which the dibasic radical 
 
 H J 
 
 of carbonic acid has replaced two atoms of hydrogen ; 
 
 or as CO s -ytt' "^ which 2 atoms of amidogen NHg 
 
 have taken the place of 2 atoms of hydroxyl HO. Urea 
 is also isomeric with ammonium carbamate and am- 
 monium cyanide. Urea crystallises in colourless 
 four-sided prisms which melt at 120° C. Very soluble 
 in cold water, and its solutions are neutral to test 
 paper. Heated to 1 50°C. , urea is converted into bi-uret 
 and cyanuric acid. With niti'ic acid urea forms nitrate 
 of urea, which crystallises out in shining rhombic 
 plates ; these crystals are less soluble than urea 
 crystals, therefore when the urine is concentrated they 
 are often formed on the addition of nitric acid. 
 
48 Clinical Chemistry. [Chap. 11. 
 
 Oxalic acid also forms oxalate of urea, which is 
 deposited as fine powdery crystals. Mercuric nitrate 
 in alkaline solutions forms with urea an insoluble 
 compound CON2H4, 4H9O1. Hypobromous acid de- 
 composes urea into water, carbonic acid, and nitrogen. 
 
 COMPOUND UREAS. 
 Sub-class A. Monureides. 
 
 6.3. Kreatiu C^HgNgO^ + H^O. — This sub- 
 stance in contact with baryta water decomposes into 
 urea and sarcosin (page 45). The crystals are oblique 
 rhombic prisms slightly soluble in cold water and 
 alcohol, very soluble in hot water, insoluble in ether. 
 The solutions ai'e neutral, and have an extremely bitter 
 taste. Acted on by sulphuric acid, it is converted 
 into kreatinin. Kreatin is chiefly found in the juice of 
 flesh, and is undoubtedly an antecedent of urea. 
 
 Ki'ea,tiiiiii C4Hj]Sr30 is formed from the fore- 
 going by dehydration. It is an extremely powerful 
 base, gives an alkaline reaction with test paper, 
 and forms well-defined basic double salts with zinc 
 chloride and silver nitrate. 
 
 Sub-Class B. Diureides. 
 
 64. Uric acid C5H4]Sr403. — There is still some 
 doubt as to the exact constitution of uric acid ; it is, 
 however, represented by the hypothetical formula as 
 consisting of one radical of tartronic acid and two of 
 urea, thus : 
 
 Tartronic acid. Urea. Uric acid. 
 
 C3H4O5 + 2(CH4N,0) = an^N^Oa + 4H,0. 
 
 From this it is held that uric acid is tartronyl 
 cyanamide, four molecules of amidogen being replaced 
 
Chap. II.] IS/ITROGENOUS BaSES. 49 
 
 by two of cyanogen, and two by the radical of tartronic 
 
 ( C,H,03 
 acid ; thus Nj*; ON 2 As deposited from acid solu- 
 
 tions it occurs in rliombic tablets of very variable form. 
 It is extremely insoluble in water and acid solutions, 
 very soluble in alkaline solutions. Uric acid is di- 
 basic, and forms with bases both neutral and acid salts, 
 of which the sodium, potassium, and ammonium are 
 of the n)ost interest ; tliese are all very insoluble in 
 water, but less so than uric acid. When in solution, 
 if these salts are decomposed by the addition of 
 concentrated nitric acid, the uric acid is separated in 
 an amorphous and hydrated form, in which it is 
 rather more soluble than in its crystalline state. This 
 amorphous form of uric acid is frequently observed 
 when concentrated nitric acid is added to urine 
 when testing for albumin, and has been erroneously 
 described as precipitated acid urates, which may be 
 thrown down when dilute acid is used, if the urates 
 were previously in the neutral form. The character- 
 istic test for uric acid is the viurexide reaction, the 
 jiurple colour developed when the crystals are heated 
 with nitric acid, and the residue touched with am- 
 monia. By oxydation uric acid yields alloxan and 
 urea ; mesoxalic acid and urea, allanturic acid and 
 urea; parabauic acid (which is oxalyl ui-ea), tartronyl 
 urea or dialuric acid. 
 
 65. Xaufhin CsH^N^Oo.— The constitution of 
 this body is unkno^Ti ; uric acid treated with sodium 
 amalgam yields xanthin and hypoxanthin. Xanthin 
 forms Avhite scales resembling beeswax, sometimes 
 deposited from urine in minute lemon-shaped plates ; 
 these dissolved in dilute hydrochloric acid, and the 
 solution slowly evaporated, yield hexagonal and pris- 
 matic crystals. Very insoluble in water (1 in 1,500), 
 freely soluble in dilute acids and alkalies. J-Teated 
 
5© Clinical Chemistry. [Chap. ii. 
 
 with nitric acid, and the residue moistened whilst 
 still hot with liquor potassse, a purple-red colour is 
 developed. A constituent of a rare form of urinary 
 calculus and gravel. 
 
 %%. Hypoxanthin C5H4N4O (syn. sarcine). — 
 Is a white imperfectly crystalline powder, rather more 
 soluble in water than xanthin. Found in the spleen, 
 thymus, muscular tissue, medulla of bones, and blood 
 of leuceemic patients. 
 
 67. Allantoin €4116^403 can be formed from 
 uric acid by boiling with lead peroxide. Forms 
 colourless hard glassy prisms of neutral reaction. 
 Soluble in cold water (1 in 160). Boiled with 
 potassium hydrate it yields potassium oxalate. Con- 
 stituent of allantoic fluid and foetal urine. 
 
 68. Carnin C7HgN"403. — Has been discovered in 
 Liebig's extract of meat ; it can be converted into 
 hypoxanthin by the action of bromine. 
 
 69. Ouanin CgHslSrsO. — A yellowish -white 
 powder nearly insoluble in water, but sokible in 
 dilute acids and alkalies. By oxydation with potassium 
 permanganate is converted into urea, oxalic acid, 
 oxy-guanin. Is a normal constituent of the semi- 
 solid excrement of birds. It has been sometimes met 
 with in the liver, pancreas, and spleen, but does not 
 appear to be a constant product. 
 
 DIVISION III. VEGETO-ALKALOIDS. 
 
 These bodies are supposed to be compound 
 ammonias, and act as powerful bases ; are the active 
 principles of certain plants. Those of highly poison- 
 ous nature are enumerated here, as they may be intro- 
 duced into the animal body either accidentally or 
 with criminal intent, when their detection becomes a 
 matter of consequence. A group of animal alkaloids, 
 the result of putrefactive changes in the tissues, have 
 
Chnp. II.] Alkaloids. 51 
 
 recently been discovered, and are named ptoamin.es ; 
 they correspond in their general reactions with the 
 vegeto-alkaloids. 
 
 70. Morphine Ci,H,(,NO, + Hp.— The crystals 
 are colourless prisms, very slightly soluble in water 
 (1 in 1,000 cold; 1 in 500 hot). Very soluble in 
 hot alcohol. The salts are more soluble in water 
 than the base. It gives an indigo-blue coloration, 
 with a neutral solution of ferric chloride. With 
 sti'ong niti'ic acid forms a deep orange-yellow com- 
 ])ound. Concentrated sulphuric acid, with a trace of 
 nitric acid, gives a violet-purple colour. Morphine 
 decomposes iodic acid with the liberation of iodine. 
 
 71. Strycliiiine C,Ji^J>i X>^. — The crystals are 
 extremely small brilliant octohedra, transparent, and 
 colourless. Slightly soluble in water (1 in 6,000 cold; 
 1 in 2,500 hot), more soluble in chloroform. The 
 solutions have an intensely bitter taste (perceptible 
 1 in 1,000,000). With concentrated sidpburic acid, 
 and a fragment of potassium dichromate, a deep violet 
 tint is produced, gradually fading on exposure. Solu- 
 tions of strychnine {-j-^jyjj grain) injected under skin 
 often produce violent tetanic spasms and death. 
 
 72. Brucine C^HofiNgO^ -f 4H2O.— More soluble 
 in water than strychnine, and is readily soluble in 
 alcohol. Is distinguished from it by the bright red 
 colour given when touched with nitric acid. 
 
 73. Curarine C,oH,.=i]Sr. — Yery soluble in water 
 and alcohol. Nitric acid gives a purple coloration. 
 Concentrated sulphuric acid colours it blue, and if 
 potassium dichromate is added, changes to violet 
 slowly fading to yellow. In this test it resembles 
 strychnine, but is distinguished from that body by 
 its ready solubility in water. 
 
 74. Atropine Ci^Ho-jlSTOs. — Ciystallises in colour- 
 less needles, slightly soluble in water, very soluble 
 in chloroform. With concentrated sulphuric acid 
 
52 Clinical Chemistry. [Ckap. ii. 
 
 no coloration in tlie cold, but on heating a yellow- 
 tinge is developed, and on adding water a rose- 
 like odour is given off. Solutions containing trace of 
 atropine have highly poisonous effects on frogs. 
 
 75. Ptoamimes. — This name has been given to 
 bodies which have been detected in exhumed corpses, 
 closely resembling, in their chemical reactions and 
 physiological effects, the vegetable alkaloids. Whilst 
 some, however, act as powerful poisons, others are 
 inactive, and a few actually counteract the effect of 
 poisonous substances. Spica, in the liquid from a 
 suppurative peritonitis, obtained bodies, some of 
 which were oily and volatile, with a strong alkaline 
 reaction and capable of forming crystalline salts, and 
 having the odour of conine. The chloroform extract 
 was extremely poisonous in its actions on frogs, and in 
 its physiological effect resembled that of curarine. 
 Sonnenschein has found, in an anatomical maceration 
 fluid, an alkaloid resembling atropine in its action. 
 Hanke has shown that the physiological action of 
 strychnine in bodies long buried may be masked by 
 ptoamines. A body resembling Sonnenschein's al- 
 kaloid has been found in bodies of patients dying 
 from typhus fever. It is interesting to observe that 
 in many instances of death resulting from poisonous 
 food, the patient showed marked typhus symptoms. 
 It appears that these bodies are generally produced in 
 substances which, after brief exposure to air, are 
 buried or excluded from air, as in corpses, tinned 
 meat, etc., and that then they are found in the most 
 internal portion. It is of importance to discover the 
 reactions which distinguish these bodies from the 
 vegeto-alkaloids, but the question is often one of 
 extreme difficulty. It has been stated that potassium 
 ferrocyanide is a reliable reagent, since ptoamines 
 reduce it, whilst the vegeto-alkaloids have no reaction 
 on it. The test is applied as follows : — The extract 
 
Chap. II. 1 Colouring Matjeks. 53 
 
 is converted into a sulphate, and a few drops of solu- 
 tion of K.,FeCyrt added ; if a ptoamineis present, Prus- 
 sian blue will be foriiiod on the additiou of a few drop.s 
 of ferric chloride. No reaction, however, is given 
 with a vegcto-alkaloid, except morphine and veratrine ; 
 these, however, can bo detected by their special tests. 
 
 INDIGO GROUP. 
 
 76. Iiidol CttHjN. — A crystalline substance which 
 is the starting point of the indigo group. It occurs 
 in the body as one of the products of pancreatic di- 
 gestion, and is said to give the characteristic odour 
 to the fieces. The addition of salicylic acid to pan- 
 creatic juice stops its formation from albuminoids ; 
 and it has been found that under the administration of 
 the acid the quantity of indol decreases exactly in 
 proportion as the quantity of phenol increases. Very 
 dilute nitrous acid gives a red colour in solution of 
 indol. 
 
 In(lig:o CjeHioNoCj. — This substance, which is 
 derived commercially from the indigo/era, is some- 
 times met with in sweat and urine, giving rise to a 
 bluish colour. It has been met with as a constituent 
 of urinaiy calculus [Med. Path. Soc. Trans., vol. xxix., 
 p. 157). The source of indigo in the body is un- 
 doubtedly from indol formed by the decomposition of 
 albuminoids by pancreatic digestion, since indican 
 C^Ji^.^ X)^i, or glucoside of indigo, is found in the 
 urine of animals after the subcutaneous injections of 
 indol, also after ligature of the small intestine, and also, 
 according to Senator, in obstructions and other afiec- 
 tions of the intestines in disease. The indol being pro- 
 bably converted into indican in the alkaline blood, but 
 deposited as indigo when it comes in contact with the 
 acid urine. However this may be, indican out of 
 the body always yields indigo as one product of its 
 
54 Clinical Chemistry. [Chap. ii. 
 
 decomposition, and indi-glucin, a sweet, non-ferment- 
 able substance which reduces Fehling's solution. Uro- 
 xanthin, a colouring matter found in the urine, strongly 
 resembles indican ; it does not, however, yield indigo- 
 blue under the action of acids. 
 
 78. Colowrmg^ matters of lnunan toody 
 are the colouring matters of the blood, haemoglobin 
 and its derivatives. The bile pigments, bilirubin, 
 biliverdin, bilifuscin, biliprasin, urobilin. The urinary 
 pigments, uroxanthin or indican, and urobilin and a • 
 black pigment melanin, found normally in the choroid 
 and in the skin of negro, and pathologically in melanotic 
 tumours, in the urine, and as a deposit in the lungs. 
 For the reaction of the various pigments, the reader 
 is referred to chapters on blood, bile, and urine. 
 
 Section B. — Inorganic Constituents. 
 
 79. Hydrocliloa-ic acid (HCl). — Chlorine in 
 the body is chiefly found in combination with the alka- 
 line oxides of soda and potash. These salts are, however, 
 variously distributed; thus, for example, in 1000 parts 
 blood corpuscles, we find 3-67 parts of potassium with 
 only a trace of sodium chloride, whilst in the plasma 
 there is' only -36 parts of potassium chloride, and as 
 much as 5 '54 parts in the 1000, The chlorides appear 
 to fulfil the following purposes in the economy: (1) 
 by furnishing the hydrochloric acid for digestion 
 (2Na^HP0, + 3CaCl = Ca32P04 + 4NaCl + 2HCI ; 
 Maly) ; (2) by aiding the metabolic processes going 
 on in the body, an increased ingestion of common salt 
 being followed by increased excretion of urea. Sodium 
 chloride is found in great abundance in all cellular 
 growths, as in cartilage, mucus, etc. In certain 
 diseases attended with increased cell formation, as in 
 cancer, in pneumonia with exudation, and in puru- 
 lent discharges, sodium chloride is present in large 
 
Chap. II.] Inorganic Acids. 55 
 
 quantities in the morbid products, and consequently 
 there is a sensible diminution in the quantity excreted 
 by the urine. H'dmr nitrate gives, in extremely dilute 
 solutions, a faint haze ; in stronger solutions a white 
 cloudy precipitate ; nitric acid will not cause these to 
 dissolve ; they are soluble, however, in ammonia, but 
 on nitric acid being added to the ammoniacal solution, 
 the silver chloride is again precipitated. 
 
 80. Hydrofluoric acid HF. — United with 
 calcium as calcium Huoride, is found in minute quan- 
 tities in the bones and teeth, occasionally in blood, milk, 
 and urine. The ash treated with strong sulphuric acid, 
 and gently heated in a glass vessel, the glass becomes 
 corroded. Large quantities of ash must be employed. 
 
 81. Phosphoric acid H3PO4. — Phosphorus is 
 one of the most important of the inorganic constitu- 
 ents of the body, and is widely distributed. In com- 
 bination it is found as a component of the complex 
 nitrogenous fats, lecithin, etc. In its oxydised form it 
 occurs as tribasic phosphoric acid. In combination 
 with soda and potash it forms the alkaline phosphates, 
 the neutral salts of which (Na^HPO^), together with 
 the alkaline carbonates, gives to blood its alkaline re- 
 action ; the acid salts NaH2P04 gives urine its acid 
 reaction. Bone earth is tricalcic phosphate Ca32P04. 
 Magnesium phosphate associated with calcium phos- 
 phate is found in all animal tissues and fluids, but to 
 a less extent ; in the excreta, however, the magnesium 
 is relatively more abundant than the calcium salt. 
 From this it has been inferred that the magnesium 
 salt is less required by the organism, and consequently 
 is not so long retained as the calcium salt, and also 
 that less is absorbed by the intestinal canal. Few 
 questions in scientific medicine afford less facts for 
 generalisation than the variations in the excretions 
 of phosphoric acid by the urine in disease. Physio- 
 logy can only tell us that the element phosphorus is 
 
56 Clinical Chemistry. [Chap. ii. 
 
 al)Solutely essential for the growth and nutrition of the 
 tissues, but cannot explain its role. Pathologically 
 we find {a) excess of phosphoric acid accompanied by a 
 proportionate increase in the elimination of urea ; (6) 
 excess of phosphoric acid without a proportionate in- 
 crease. In the first instance the increase is probably 
 due to increased tissue metabolism generally ; in the 
 second, probably only the nervous system is involved. 
 The compound known as triple phosphate, or ammonio- 
 magnesiuin phosphate P04Mg(]SrH4) + 6H2O, is met 
 with in ammoniacal urines ; this salt combined with 
 calcium phosphate forms the basis of one of the most 
 frequent forms of phosphatic calculus, known as the 
 fusible calculus. Phosphoric acid gives a yellow preci- 
 pitate with silver nitrate soluble in both nitric acid and 
 ammonia. A yellow precipitate is given with ammo- 
 nium molyhdate in nitric acid. An acid solution of 
 uranic nitrate is decomposed by phosphoric acid, and 
 uranic phosphate is precipitated ; this latter gives no 
 stain with ferrocyanide of potassium test-paper, which 
 uranic nitrate does ; upon this fact the process for 
 estimating quantitatively phosphoric acid is based. 
 {Q.v. Urine.) 
 
 82. SulpliuFic acid H^SO^. — Sulphur is found 
 in most protein bodies, and in many products of 
 their metabolism, as cystin and taurin. It is also 
 largely introduced into the body with vegetable sub- 
 stances. Only a small portion of the sulphur in the 
 body passes out as sulphuric acid, a considerable part 
 being discharged either unoxydised or only partially 
 Dxydised by the bowels, and some by the skin and 
 ej)idermal appendages. It is thus difficult, from the 
 increase or diminution of sulphuric acid in urine, to 
 form an estimate of the degree of metabolism of the 
 sulphur compounds in the body. The sulphuric acid 
 in the urine is for the most part combined with potash 
 an.d to some extent with lime. About 0*4 grain of 
 
Chap. II.] Inorganic Bases. 57 
 
 sulphur also passes into urine in a partially oxydised 
 state in the twenty-four hours. The sulphates oj*e 
 detected in acid solutions by the addition of barium 
 chloride or nitrate, which throws down a dense cloud 
 of barium sulphate. 
 
 8.3. Sulplio-cyanatc of potassium CNKS. 
 — A trace of this substance is found in saliva. Petten- 
 kofler believes it to be derived from decomposition 
 occurring in the ca\'ity of the mouth, being derived 
 from urea and sulphate of potash. Dr. S. Fenwick, 
 however, has [Med.-Chir. Trans., 1882) endeavoured to 
 show that the presence of sulf)ho-cyanate in saliva is 
 not due to accidental causes, but is regulated by the 
 operation of general laws, and the amount present 
 varies considerably in disease. The chief ])oint of 
 practical importance is its relation to medico-legal 
 inquiries in cases of opium poisoning, since meconic 
 acid gives the same reaction with ferric; c/n/orisWe as the 
 sulpho-cyanate, viz., a cherry-red ; this, however, dis- 
 appears on the addition of mercuric chloride, which is 
 not the case with the colour pz'oduced by meconic acid. 
 
 84. Liimc CaO. — Lime must be considered as 
 one of the chief mineral constituents of the body. As 
 phosphate of lime, it ranks next to water in the im- 
 portance of its physical properties to the organism. 
 Its salts constitute (54 per cent, of the weight of 
 the skeleton, viz. : calcium phosphate, 51 '04 ; calcium 
 fluoride, 1'9 ; and calcium cai-bonate, 11 "4 per cent. 
 In blood the calcium salts are in excess in the plasma, 
 1000 parts yielding "298 part of lime, whilst the same 
 weight of corpuscles give only "094. In muscular tissue 
 lime is present, ranging from "230 to "311 part in a 
 1000. Lime salts are tolerably abundant in the gastric 
 juice, about 1-48 of calcium phosphate in the 1000. 
 Maly believes the hydrochloric acid of the gastric juice 
 is derived from the decomposition of chloride of cal^ 
 cium(2Na,HP0, + sCaCl = Ca32P0, + 4XaCl + 2HCI). 
 
58 Clinical Chemistry. [Chap. 11. 
 
 Only a small proportion of tlio lime injected is 
 excreted with the urine. In experiments on dogs it 
 was found that when calcium chloride was given by 
 the mouth nearly all the lime was passed off by the 
 bowel as carbonate, only a small increase in the ex- 
 cretion of lime by the urine being noted, and that as 
 phosphate. The chlorine appeared in combination 
 with sodium as chloride of sodium. In rickets it has 
 been said there is a great increase in the quantity 
 of lime salts excreted in the urine, but the fact is by 
 no means established ; recent observations have ac- 
 tually found a diminution, which was most marked 
 when the disease was at its height. It is probable 
 that the idea that an increase of lime excreted took 
 place in rickets was due to the mere deposition of the 
 earthy salts being taken for excess. The urine of rickety 
 children is frequently alkaline, and consequently is 
 often turbid from deposited calcium phosphate. Local 
 deposits of calcium carbonate are frequently met with 
 in tissues which have suffered from general impairment 
 of vitality, or from diminished nutritive supply. In 
 these cases it is probable that, owing to the escape 
 of the free carbonic acid, which keeps this salt in 
 solution, from the stagnated fluids, the calcium salt is 
 precipitated, and on account of the degeneration of the 
 tissues is not taken up by them. Salts of lime form 
 the insoluble portion of the ash ; to obtain them in 
 solution they must be dissolved in as small a quantity 
 as possible of dilute acetic acid. Ammonium oxalate 
 added to this solution gives a copious white precipitate 
 of calcium oxalate. Mineral acids should not be used 
 to dissolve the ash, as the calcium oxalate would re- 
 dissolve if the acid was in excess. The amount of 
 lime present is best determined by weight. For this 
 purpose the insoluble portion of the ash is weighed, 
 and the w-eight recorded. It is then dissolved with 
 acetic acid, and the solution diluted by the addition of 
 
Chap. II.] InORCANIC JSasES. 59 
 
 about ton times its woiglit of distilled water. To this 
 solution add saturated solution of ammonium oxulate, 
 and allow to stand for twelve hours. Filter through a 
 filter the weight of whose ash is known.* The pre- 
 cipitate in the filter consists of calcium oxalate. The 
 filtered solution is magnesia, which should be set aside 
 for determination of that substance if required. Wash 
 the precipitate on the tilter with distilled water. Dry 
 over water-bath till the filter and contents cease to 
 lose weight. Place the filter and contents in a small 
 platinum capsule with cover, whose weight is known; 
 beat till whole is reduced to white ash. When cool 
 convert the lime into sulphate by the addition of a 
 few drops of sulphuric acid. Again heat carefully, 
 covering to prevent loss. Weigh the capsule when 
 cold. Now, when the weight of the ash of the filter 
 and the weight of the capsule are deducted from the 
 total weight, we have the weight of sulphate of lime, 
 and to calculate this as caustic lime, we multiply by 
 0-4118. 
 
 85. Magnesia MgO. — Magnesium phosphate 
 associated with calcium phosphate is found in all the 
 animal tissues and fluids, but in smaller quantities. 
 Little is knowTi as to the purpose it fulfils in 
 the economy. The chief clinical interest attaching 
 to it is from it forming, as triple phosphate, a variety 
 of urinary gravel, and a calculous crust in cei'tain 
 morbid conditions of the urinary organs, which induce 
 the formation of A'olatile (ammonia) alkali. The 
 triple phosphate is, however, generally associated 
 with calcium phosphate, the mixture of the two salts 
 forming a mass readily fusible under the blow- 
 pipe. Neutral solution of magnesia throws down a 
 bulky gelatinous precipitate with ammonia. The ad- 
 dition of sodium fhospliate to a magnesian solution 
 
 * This is done by incinerating a filter of the same size and 
 weight as tlie one used, and weighing the ash. 
 
5o Clinical Chemistry. [Chap. n. 
 
 gives rise to a white precipitate of magnesian phos- 
 phate, whilst the addition of ammonia throws the 
 ammonio-magnesium phosphate. Magnesia is esti- 
 mated by weight. The ash is treated, in the first 
 instance, as directed for lime. The filtrate, obtained 
 after the removal of the precipitate caused by am- 
 monium oxalate (lime oxalate), is treated with excess 
 of ammonia, and allowed to stand twelve hours. 
 The resulting precipitate is collected on a filter, the 
 weight of whose ash has been previously ascer- 
 tained ; the filter is then dried till it ceases to lose 
 weight. When dry it is to be placed in a small 
 platinum capsule whose weight is known, and heated 
 to a white heat till a white glassy mass is left at the 
 bottom of the capsule. This is magnesium pyro- 
 phosphate. Weigh the capsule when cold, and by 
 deducting the weight of the ash of the filter and 
 the weight of the capsule from the total weight, the 
 result gives amount of magnesium pyrophosphate ; 
 by multiplying this weight by 0-3604 we get the 
 amount of magnesia present as oxide. 
 
 86. Ammonia NHg. — Ammonia in a free 
 state is sometimes found in urine ; generally, however, 
 it is in the form of carbonate, the result of ureal de^ 
 composition. It has been detected in the breath of 
 typhus patients. The chief salt of interest it forms 
 is ammonium urate, a constituent of the urinary 
 excretion of insects, reptiles, and birds, and is fre- 
 quently met with as a urinary deposit in human 
 beings. 
 
 87. Potash KHO. — This body, with soda, 
 forms the soluble portion of the ash. Potash is 
 widely distributed throughout the body, but in very 
 variable proportions. It is more abundant in the 
 solid tissues .and the corpuscles than in the secre- 
 tions and plasma of the blood ; in this respect 
 being the very opposite of the soda salts. The 
 
cnap. II.] Inorganic J^ASEs. 6i 
 
 potash salts seem to have a greater activity than 
 those of sodium. Ringer has found them more 
 poisonous, as far as their action on the heart is 
 concerned, than the sodium salts. It is said that 
 a dog fed on nothing but Liebig's extract dies 
 sooner than a dog not fed at all, on account of 
 the potash salts exerting a poisonous influence. Dr. 
 Garrod, some years ago, found that the amount of 
 potash salts in urine were diminished in scurvy, 
 and suggested that this disease was in some way 
 connected with a deficiency of this base in the 
 body, and that dietaries of persons afi'ected with the. 
 disease were deficient in potash. Furtlier examination 
 has not shown this to be correct, since peas and other 
 articles of a sailor's diet have been shown to contain 
 a sufficiency of potash. I have, however, recently 
 confirmed Dr. Garrod's observation as to the defi- 
 ciency of potash in the urine of scorbutic patients, 
 but I believe that the diminution is not due to 
 diminished ingestion, but to the base being withheld 
 by the blood in order to maintain its alkalinity, 
 which has been impaired by the withdrawal of the 
 alkaline carbonates supplied by fresh meat, vege- 
 tables, and fruits. Solutions of potash salts give, 
 with platinum bi-chloride, when sKghtly acidulated 
 with hydrochloric acid, a yellow crystalline precipi- 
 tate of potassium platinic chloride. The estimation 
 of potassium and sodium can be conveniently done 
 together, and will be considered in the next para- 
 graph. 
 
 88. Sodiiiin NaO is more abundantly met with 
 in fluids than in the solid textures of the body, in this 
 case being the reverse of the potassium salts. Thus, 
 we find in blood ])lasma 5 "540 parts of sodium chloride, 
 1-532 parts of soda, and •271 part of sodium phosphate, 
 as compared with -359 part of potassium chloride and 
 •281 of potassium sulphate in 1000, Whilst in the 
 
62 Clinical Chemistry. [Chap. ii. 
 
 blood corpuscles the reverse obtains ; for in 1000 parts 
 "we have 3 "6 79 potassium chloride, 2-343 potassium 
 phosphate, "132 potassium sulphate, against "341 of 
 soda and -635 sodium phosphate. The acidity of the 
 urine is chiefly due to acid sodium phosphate 
 NaH2P04. The bile, too, is particularly rich in 
 soda salts, containing about 2-5 per cent, of sodium 
 chloride and 6 per cent, bile salts, in the form of 
 glycocholate and taurocholate of soda. The action 
 of soda salts on the excitability and contractility of 
 the heart is decidedly less than that of potash salts, 
 but it is nevertheless marked. ^The chief clinical 
 interest attaching to salts of soda is the formation of 
 gouty tophi and calculous infarcts in the tubules 
 of the kidney, composed of sodium urate. A con- 
 centrated solution of sodium salt gives a white 
 crystalline precipitate with antimioniate of potash. 
 Soda salts also give a characteristic yellow tinge to the 
 blow-pipe flame. Potassium and sodium can be deter- 
 mined quantitatively by the same operation. Dissolve 
 a definite quantity of ash in boiling distilled water. 
 Filter. Bring the filtrate up to 60 cc. by the addition 
 of distilled water, or diminish by evaporation to that 
 bulk. Of this quantity take 30 cc. (which will repre- 
 sent half the quantity of the soluble salts in the ash), 
 add a few drops of ammonia and ammonium carbonate. 
 Set aside for twelve hours, filter through a very small 
 filter. Acidulate the filtrate with a few drops of 
 hydrochloric acid, and place it in a platinum capsule 
 of known weight. Evaporate to dryness, and then 
 heat gradually to redness to drive ofi" ammoniacal 
 salts. Weigh when cool ; deduct weight of capsule ; 
 result gives weight of potassiu'in and sodium chlorides, 
 of half the amount of ash originally taken for ex- 
 periment. To estimate the potash, dissolve the 
 residue in the platinum capsule in as little water 
 as possible, and then add an alcoholic solution of 
 
Chap. II. 1 IXOKCANIC BaSES. 63 
 
 platinic liichloride till tlio solution acquires a tlcep 
 yellow colour ; evaporate to luiar dryness, and then 
 add 50 cc. of absolute alcohol and 10 of ether. 
 Set aside for twenty-four hours, frequently stirring. 
 Collect precipitate on weighed filter ; wash it with 
 alcohol ; dry it. Weigh ; deduct weight of filter. 
 The remainder gives amount of potassium platino- 
 chloridc (100 parts of which equals 30"/)l potassium 
 chloride). Now, as we have learnt the combined 
 weight of the potassium and sodium chlorides from 
 the first y)art of the process, we have only to 
 deduct the Aveight of the now ascertained potassium 
 chloride from the weight of the two chlorides, to find 
 the difference, loJiich is the aniount of the sodium 
 chloride. To get the amount of potash and soda we 
 have to multiply the weight of potassium chloride by 
 0-6317 and the sodium chloride by 0-5302. The 
 result being the amount of potash and soda in the 
 ash, in the 30 cc. of the dissolved ash, or exactly half 
 the amount of the whole ash dissolved in the first 
 instance. The object of dividing the original solu- 
 tion being, of course, to reserve a portion in case of 
 accidents, or a desire to check the process at any 
 point 
 
 89. Iron FoOj. — Traces of iron are met with 
 in the ash of most tissues and fluids ; as a proto- 
 chloride in the ash of gastric juice, and as a phosphate 
 in muscular and splenic juice. Combined with 
 globulin as htemoglobulin, it forms the colouring 
 matter of the blood. Preyer from an average of eleven 
 cases gives 0-056 grm. of iron and 13-45 grms. of 
 haemoglobin in 100 grms. of human blood. It is 
 probable that the iron of the eftete blood-corpuscles 
 passes away with the bile, recent observations 
 tending to show that the coloui-ing matters of the bile 
 are produced from hoeniatin by reduction, due to the 
 action of the bile acids on haemoglobin. When iron 
 
64 Clinical Chemistry. [Chap. ii. 
 
 salts are taken an increase of this metal is found in 
 the bile. The salts of iron are met with as proto or 
 ferrous salts, and per or ferric salts. The former give 
 white })recipitates with caustic alkalies and light blue 
 precipitates with potassium ferrocyanide ; the latter 
 a reddish-brown precipitate with caustic alkalies and 
 a deep blue precipitate with potassium ferrocyanide. 
 The amount of iron in the ash of any tissue or fluid is 
 determined by the standard solution of potassium 
 permanganate. This was formerly the only method 
 by which the amount of iron ia blood could be deter- 
 mined. Since, however, the proportion of iron to 
 haemoglobin has been ascertained, the metal can be 
 estimated quantitatively through the determination of 
 the haemoglobin, either by Hoppe Seyler's or Gower's 
 method. The procedure by these methods will be 
 treated more conveniently when we consider the 
 variation occurring in the amount of haemoglobin in 
 disease. (Vide Blood.) 
 
 90. Silica SjOj. — Silica is a constituent of the 
 epidermal tissues ; it is nearly always present in the 
 faeces, and occasionally in the blood, bile, and urine. 
 Silica may be obtained from the ash of any of the 
 substances in which it is present, by fusing the ash 
 with eight times its weight of sodium carbonate, a.nd 
 boiling the mass in water ; on the addition of hydro- 
 chloric acid the silica is partially precipitated as a 
 gelatinous mass. The acid solution is now evaporated, 
 and the residue treated with some more hydrochloric 
 acid and dried. The silica will then be left as a white 
 insoluble powder, 
 
 91. l-ead Pb; arsenic AsgOg; copper Cu. 
 — These substances are only incidentally present 
 in the tissues, and are apparently in no way necessary 
 to the maintenance of their functions. It has been 
 stated that arsenic and copper are constantly present 
 in minute quantities in the human body. The method 
 
Chap. III.] Blood. 65 
 
 of sepiu-iitiug learl and arsenic from the tissues and 
 fluids in cases of poisoning is detailed in the chapter 
 on morbid disestiou and on urine. 
 
 CHAPTER III. 
 
 BLOOD — CHYLE — LYMPH — MILK. 
 
 Examination of morbid blood. — Of all 
 
 branches of pathological chemistry, less advance has, 
 pei'haps, been made in determining the changes 
 which blood undergoes in disease than in aviy other 
 direction. Some excuse may be offered for this 
 apparent neglect, in the ditticulty of obtaining blood 
 in sufficient quantity for analysis, a difficulty that did 
 not exist in days when bleeding was general and 
 regarded as part of the ordinary treatment. Also, the 
 methods of research until recently have been very 
 defective. The study of the chemistry of morbid blood, 
 however, must be seriously undertaken before we can 
 expect to judge of the eftects produced by even 
 primary alteration of the blood in disease. For as yet 
 how little do we know of the variations that daily and 
 hourly occur in the chemical composition of normal 
 blood, and what is the action, physical as well as 
 chemical, that each of its constituent elements has on 
 the albumins, fats, .salts, and water that compose the 
 tissues, and how far excess or diminution of these 
 constituents influences oxydation and nutrition in 
 the body. 
 
 9l'. Variation between tlie water and 
 solids.— Specific jp'avity. — The following figures 
 give approximatively the composition of normal blood 
 in 100 parts. Water, 79-5; solids, 20 -5 ; serum 
 
 F 
 
66 Clinical Chemistry. [Chap. iii. 
 
 albumin, 7 "2; fibrin, 0-21; hsemogiobin, 11 '5; fatty- 
 matters, 0'18; extractives, 0'32; ash, 0'81. 100 parts 
 of blood serum contain water 90 "5 parts ; solids, 
 9 '6. The proteids varying from 8 to 9, and the 
 fat extractives and salts from 2 to 1. 100 parts 
 of wet blood-corpuscles yield water, 56 "5; solids, 43 '5; 
 hsemogiobin, 41-1; other proteids, 3-9; fats, chiefly 
 cholesterin and lecithin, "37. The proportion of water, 
 however, varies considerably, and probably ranges from 
 76 to 80 in healthy blood under the influence of 
 normal physiological conditions, the ingestion of fluids, 
 of solid food, and the activity of the renal and 
 cutaneous excretions. The proportion of water to the 
 solids can be ascertained by evaporating a small 
 quantity of blood in a weighed platinum capsule, till 
 it ceases to lose weight. Then, if z represents the 
 weight of the blood evaporated and y the loss sus- 
 tained by evaporation, then ' = x the propor- 
 tion of water in 1000 parts. The specific gravity- 
 is ascertained by means of a small flask fitted with 
 perforated stopper for the insertion of a thermometer. 
 The fiask is then filled M'ith distilled water at 15° C, 
 and weighed ; it is then emptied and dried, and 
 then filled with defibrinated blood at the same 
 temperature and again weighed. Then if a represents 
 the weia;ht of the distilled water and h the weight 
 
 of the defibrinated blood, — = the specific gra^vity of 
 
 the blood ; thus, if the weight of the flask filled with 
 distilled water is 25-573 grains, and the weight of the 
 flask with defibrinated blood is 27 "160 grains, then 
 
 — - = 1'060. As, however, liquids expand and 
 
 25-57a ' ^ ^ 
 
 contract by alteration of temperature, a coi-rection is 
 
 necessary if the two fluids are weighed at di-fferent 
 
 temperatures. Practically, however, if both weighings 
 
Chap. III.) Reaction of Blood. 67 
 
 are conducted at the same time and in Hk; same room 
 very little diflereiice occurs ; if it docs, it can be 
 corrected by plunging the; bottle in warm water if the 
 temperature be too low, or into cold water if too high. 
 The following gives the maximum and minimum 
 percentage amount of water in different diseases as 
 recorded by trustworthy observers. Normal blooil, 
 78-8—80; scurvy, 84-9— 83-5; chloro.sis, 8G-8— 81-8; 
 cancer of liver, 88'7 ; chronic Bright s disease, 80 8 — 
 88*7; puerperal eclamp.sia, 77*8 — 80; diabetes mellitus, 
 79-4— 80 2 ; cholera, 74-0 — 75-0. There are many 
 analyses of blood in acute diseases, but their value is 
 impaired by the fact that they were generally made 
 after repeated venesections, which of course in itself 
 lendei-s the blood more watery. 
 
 93 Reaction. — Acid and acid salts are continu- 
 ously entering the blood. (1) Tliey may be introduced 
 into the body from without in the food. The quantity, 
 however, thus derived under ordinary conditions is 
 comparatively small, since nearly the whole of the 
 saline constituents of the food are alkaline, or become 
 so by conversion in the system. Still, a small quantity 
 of acid sodium phosphate is derived from the juice of 
 flesh, and this passes no doubt unchanged into the 
 blood. (2) Acid, too, is formed in the alimentary 
 canal fi'om fermentative decomposition of the saccharine 
 matters taken with the food, or of the amylaceous 
 principles that have been converted into sugar. (3) 
 Lastly, acid is generated in the tissues of the body. 
 
 In spite, however, of this constant entrance of acid 
 into it, the blood of the living body is always alkaline, 
 no doubt because the chief acid salt (sodium bicai'- 
 bonate) has an alkaline reaction. What the degree of 
 alkalescence of noi-mal blood is has not been determined, 
 but it is probable that it has certain definite limits 
 which caimot be passed in either direction without 
 causing disturbance of healthy nutrition. In fact, great 
 
68 ' Clinical Chemistry. [Chap. hi. 
 
 difficulty is experienced in reducing the alkaline 
 reaction of the blood. Hoffmann, wlio fed pigeons for 
 a considerable time on food yielding only an acid ash 
 (yolk of egg), found that however great the tendency 
 of uric acid and of the acid salts of [)hosphoric acid to 
 combine with bases, yet these were not withdrawn 
 from the alkaline blood, but were evidently withheld 
 to maintain its alkalinity. Loscar, by introducing 
 diluted mineral acids into the stomach, succeeded in 
 reducing the alkalescence of the blood, but not con- 
 siderably, and the conclusion he arrived at was that 
 the organism retained free alkali with great energy. 
 In some of his experiments the quantity of acid intro- 
 duced into the stomach would have made the whole 
 animal acid if it had been absorbed and excreted 
 again. From this Loscar infers that the organism 
 possesses certain " regulative mechanisms " which 
 maintain the equilibrium between the acids and 
 alkaline bases in the system. These experimental facts 
 seem to be borne out by what occurs in scurvy. That 
 disease, as has been well estabhshed, is brought about 
 by the prolonged and complete withdrawal of the 
 organic vegetable acids and their salts from the dietary 
 of those affected. These organic salts, as is well 
 known, by oxydation in the blood yield alkaline carbo- 
 nates. Now, the alkaline carbonates are the salts 
 chiefly concerned in maintaining the alkalescence of 
 the blood, and it appears when these are largely with- 
 drawn, as happens when scurvy is induced, the proper 
 degree of alkalescence of the blood is maintained with 
 difficulty, and in order to secure it some other alkaline 
 salt is retained instead of being excreted.* Thus, I 
 found, after the withdrawal of fresh vegetable food for 
 eighteen days, the total quantity of phosphoric acid 
 Tiassed in the twenty-four hours was slightly reduced, 
 whilst the phosphoric acid in combination with the 
 * " General Pathology of Scurvy," Lewis. 1877. 
 
Chap. III.] Reaction of Bi.oon. 69 
 
 alkaline oxides was reduced nearly one half. Again, in 
 a case of scurvy, it was found that the alkaline phos- 
 phates increased rapidly on the resumption of an 
 antiscorbutic diet, although the amount of phosphoric 
 acid ingested was the same in scorbutic and antiscor- 
 butic rations respectively ; these two facts pointing to 
 the conclusion that the alkaline phosphates are retained 
 in the system when the alkaline carbonates are with- 
 drawn, and discharged when these are again supplied. 
 All experiments made on animals with a view to reduce 
 the alkalinity of the blood or to neutralise it have 
 ended sooner or later in the death of the animal; and if 
 the process has been a slow one, the definite patho- 
 logical changes will be found to have occurred in the 
 blood and tissues, closely i-esembling the changes found 
 in the Ijodies of patients dying from scurvy, viz. dis- 
 solution of the blood globules, ecchymosis in the heart, 
 blood stains in the mediastinum, gums, and mucous 
 surftices ; whilst the muscular structure of the heart, 
 and the muscles generally, as well as the secreting cells 
 of the liver and kidneys, become gi'anular and even 
 distinctly fatty. Lastly, Dr. Gaskell has shown, 
 experimentally, that a dilute alkaline solution acts upon 
 the muscular tissues of the heai^t so as to produce a 
 powerful contraction, whilst dilute acid solutions pro- 
 duce an opposite effect, and that the muscles of the 
 smaller arteries are acted upon in the same w-ay. 
 These facts seern to point to the conclusion that one 
 factor at least upon which the constriction of the 
 nniscles both of heart and arteries depend, is the 
 alkalinity of the fluid surrounding them. It is not 
 unreasonable, therefore, to surmise that vai'iations of 
 the degree of alkalinity would not be unlikely to lead 
 to disturbances of circulation and so effect a secondary 
 chemical influence on nutrition, as well as a direct one. 
 The two salts chiefly concerned in the maintenance 
 of the alkalinity of blood are neutral sodium phosphate 
 
70 Clinical Chemistry. [ch.ip. hi. 
 
 Na^^HPO^, and acid sodium carbonate (bicarbonate) 
 NaHgCOg ; it is owing to this composition that the 
 seeming paradox of the separation of acid secretion, 
 such as urine and the gastric juice, from the alkaline 
 blood can be explained. [Vide §§ 8, 107, and 134.) 
 No precise observations have been made as to varia- 
 tions in the alkalinity of the blood in disease. Garrod 
 has found it diminished in a case of gout ; it has also 
 been found lessened in the blood sei'um in chronic 
 Bright's disease and in cholera. This particular branch 
 of enquiry ought to yield abundant information to the 
 clinical enquirer, with respect to the nature of such 
 diseases as acute rheumatism, gout, scurvy, and dia- 
 betes mellitus. The serum from a blister may be used, 
 or sufficient blood for the purpose can be readily ob- 
 tained by means of the artificial leech. This should be 
 detibrinated, and placed in a beaker. Then from aMohr's 
 burette, a standard solution of crystallised tartaric acid, 
 1 cc. of which is equivalent to'OOi grm. sodium hydrate, 
 is to be added. This solution is gradually dropped 
 into the beaker containing the blood, and a drop trans- 
 ferred after each addition by means of a glass rod to a 
 plaster of Paris plate, stained with a solution of blue 
 litmus. The addition of the acid solution is continued 
 till a faint red stain is given to the plate by the drop 
 placed in it. The number of cubic centimetres of the 
 standard solution employed to neutralise the blood, 
 multiplied by -004, gives the alkalinity of the quantity 
 of blood taken in terms of sodium hydrate. In 
 preparing the plate care must be taken to obtain the 
 plaster of Paris free from alkaline reaction, and to 
 remove any alkali fi-om the litmus. This is done by 
 thoroughly dissolving 20 grammes of litmus in 150 
 cubic centimetres of water, and allowing the solu- 
 tion to stand twenty-four hours, then filtering. The 
 precipitate is again dissolved in 250 centimetres of 
 distilled water, and allowed to stand for twenty-four 
 
Chap. 111.1 J'lliRlN OF Bf.OOD. 7 1 
 
 liours ; it is then divided into two equal portions. 
 Una is treated with dihite acid, added drop by 
 drop by means • of a ghiss rod till the solutioii is 
 faintly red ; it is then added to the other portion. 
 The plaster of Paris plates are then soaked in 
 the resulting violet-blue solution. It is absolutely 
 necessary to prepare the plate before obtaining the 
 blood, since by keeping, even a few hours, the 
 alkalinity of the blood is diminished. 
 
 94. Fibrin. — Wlieu blood is drawn from the 
 body it separates into clot and serum. The former 
 consists of fibrin, holding in its meshes the blood 
 corpuscles ; these latter can be removed by washing 
 the clot Avith a gentle stream of water. The amount of 
 fibrin in normal blood, as according to recent analyses, 
 ranges from -21 to '23 parts in 100. The older 
 analyses state it as "31 to '34. In many diseases it is 
 considerably increased. The following gives some of 
 the more reliable observations : Acute bronchitis, from 
 •43 to -63 in 100 parts. Pneumonia, -40 to 1'05. 
 Pleurisy, before effusion, "58 to "59 ; pleurisy, after 
 effusion, -40 to "48. Acute rheumatism, the mean 
 of forty -three observations, '67. Puerperal convul- 
 sions, '44 to 'GO. Heart disease, mean of twenty-four 
 cases, "34 ; advanced heart disease, '25, mean of thirty- 
 one cases. Chloi'osis, mean of nine cases, -29. Scurvy, 
 •45 to -65. Diabetes, -19 to -24. Phthisis, mean of 
 twenty-two analyses, -44. Puerperal fever, -43 to -51. 
 The so-called " buffy coat," which sometimes forms 
 on the surface of the clot in blood drawn in certain 
 diseases, does not necessarily depend on the amount 
 of fibrin present, but on delay in the act of coagu- 
 lation, and the tendency of the red corpuscles to 
 aggregate together, which is generally observable 
 in the inflammatory state. These, therefore, have 
 a tendency rapidly to subside, leaving the white 
 corpuscles, which are lighter in the upper portion 
 
72 Clinical Chemistry. [Chap. iii. 
 
 of the clot, and these give it the buffy appearance. The 
 antecedents of fibrin in the blood are paraglobulin, or 
 fihrino-plastic substan ce, ajid fibrinogen ; whilst for the 
 conversion of fibrinogen into fibrin outside the body, 
 the action of a third body, the fibrin ferment, is 
 required (§ 21). The addition of this latter body to 
 fluids containing fibrino-plastic and fibrinogen imme- 
 diately brings about coagulation, as may be seen some- 
 times in its addition to chylous urine, in which there 
 is but little coagulum, causing at once an abundant 
 separation. This is also occasionally observed with 
 hydrocele fluid. Fibrin is estimated quantitatively 
 in uncoagulated blood by drawing the blood directly 
 into a bottle, whose weight has been accurately deter- 
 mined, fitted with a perforated stopper, through which 
 a rod is inserted, to which is attached a brush of fine 
 wire. When a sufficiency of blood has passed into 
 the bottle, the rod with attached whisk is stirred 
 round and round for a quarter of an hour, when 
 the fibrin will attach itself to the wires composing the 
 brush. The outside of the bottle is now to be care- 
 fully cleaned and dried, and then weighed ; the 
 addition to the original weight of the bottle and 
 apparatus gives the amount of b.iood employed. Now 
 pour the contents of the bottle into a muslin strainer, 
 and with a pair of delicate forceps pick ofi' from the 
 wires the adhering fragments of fibrin, and place them 
 on the muslin strainer, wash most thoroughly with 
 cold water till they are completely freed from 
 adhering corpuscles or serum, and subsequently wash 
 with ether. Then remove them to a weighed platinum 
 capsule, and dry over water-bath till it ceases to lose 
 weight, and let it cool in chamber of balance, over a 
 beaker of strong sulphuric acid. Then weigh ; the 
 increase of weight in the platinum capsule gives the 
 amount of fibrin. This, however, contains some 
 inorganic residue j in order to obtain the fibrin pure 
 
Chap. III. I COLOURIXC AfATTER OF Bl.OOP. 7.^ 
 
 it must be incinerated. For tliis purpose the capsule 
 is heated till only a white ash is left, and is iigaiix 
 weighed. The loss in weight deducted from the 
 weight of the fibrin before incineration gives the 
 amount of pui-e fibrin. Supposing the original weight 
 of blood was 31-2 grammes, and the weight of pure 
 fibrin obtained from this 'OGG grannnes, then 
 
 TT^^ — = -21 granunes or fibrin m 100 parts 01 
 
 blood. When, however, we have to deal with blood 
 already coagulated we have to cleanse the already 
 separated filjrin from the blood corpuscles, a proceeding 
 of considerable difficulty. This is done by weighing 
 100 centimetres of blood in a beake}-, and draining off 
 tlie serum through a linen strainer, washing well 
 with cold water; after a while fold the strainer, as 
 a bag, over the contents ; wash with water and 
 knead the contents till all the corpuscles are re- 
 moved, and the clot decolorised. Then transfer the 
 filaments by means of a delicate pair of forceps to the 
 platinum capsule, and proceed as above. 
 
 95. Colcui'iiig matter of the blood is con- 
 tained in the red corpuscles. These are minute 
 discoidal bodies, nearly transparent, of a yellowish 
 colour, varying in diameter from -g oVo ^'^ toW °^ ^^''■ 
 inch, the average being put at -stj^o (or 7-9 micro- 
 millimetre), and abouty^ioy inch (1-8 micromillimetre) 
 in thickness. The human blood corpuscles contain no 
 nucleus. In fresh unaltered blood the surfaces of 
 the red corpuscles are bi- concave, and form peculiar 
 rolls, like coins adhering together. Under certain 
 abnormal conditions, or when the blood is diluted 
 with saline solutions, as sodium chloride, sodium 
 sulphate, magnesium sulphate, etc., the corpuscles 
 lose their smooth circular outline, shrinking, and 
 becoming crenate. On the other hand, wlien placed 
 in fluids of low density they swell up, and become 
 
74 Clinical Chemistry. [Chap. in. 
 
 bi-convex and globular, and may even burst. The 
 red corpuscles are formed of a delicate membrane^ 
 stroma (oikoid, Briicke), which contains the colouring 
 matter (zooid) hsemoglobulin, cholesteriu, lecithin, and 
 inorganic salts. The stroma is the colourless portion 
 of the living blood corpuscle ; it is insoluble in water 
 and serum, and in sodium chloride solutions, but 
 freely soluble in ether, chloroform, caustic soda, 
 ammonia, and in solutions of the bile acids and urea. 
 The stroma appears to combine with the hsemoglobin, 
 and, so to speak, fixes it, but tlie union is very feeble, 
 and very slight disturbing influences set free the 
 colouring matter. The hsemoglobin in the living 
 blood is combined with an alkali, probably potash, to 
 keep it in solution, as otherwise it is very insoluble, 
 and would crystallise out. 
 
 One hundred parts of human dried corpuscles con- 
 tain hajmogiobin, 86-79; proteids, 12-24:; lecithin, 
 0-72; cholesterin, 0-25 (HoppeSeyler). The corpuscles 
 may be obtained for analysis by rapidly defibrinating 
 blood, and then adding to it ten times its volume of 
 a 10 per cent, solution of common salt, and setting 
 aside in a cool place, when the corpuscles will be 
 deposited. They are then to be collected on a filtei', 
 and washed thoroughly with sodium chloride solution 
 till thoroughly free from serum. The mass is then 
 placed in a weighed caj)sule and dried ; the weight 
 after drying represents the amount of corpuscles 
 present in a certain quantity of blood. 
 
 (a) Clinical determination of hcemoglohin. — In 
 disease the amount of hsemoglobin varies consider- 
 ably. According to Quincke the following are some 
 of the chief deviations observed : Taking 11 -5 to 12-0 
 to represent the percentage amount of hsemoglobin in 
 normal blood, then in a case of cirrhosis of liver, with 
 epistaxis, it was 10"1 per cent.; in chlorosis, 5*3, 
 after taking ii'on, 9*92; in leucocythsemia, 5-8 ; in 
 
Chnp. III.] Co LOUR I KG Matter of Blood. 75 
 
 Brin[ht's disease, granular kidney, 8'5 and 10-60 ; with 
 larire fatty kidney, 10-30 and 10-70; in diabetes 
 niellitus, 14-4 ; in phosphorus poisoning, 14-9. For 
 clinical purposes the amount of haemoglobin present 
 in blood may be estimated by means of the number of 
 blood corpuscles, and their depth of colour. This is 
 done by counting first (by means of the hpemocyto- 
 meter), the number of corpuscles in a small quantity 
 of blood, and then comparing the colour of the same 
 blood with a tint of a solution of hfemoglobin of 
 known strength. For this purpose the instruments 
 devised by Dr. Gowers* are the ones generally 
 employed. First of all the number of the corpuscles 
 has to be determined. This is done by the 
 hamocyfomeler. The proceeding is as follows : 5 
 (u1)ic millimetres of blood are drawn into a capillary 
 tube from a puncture, by means of a spear-pointed 
 needle in the finger, and blown into a cup-like cell 
 containing 99.5 cubic millimetres of solution of 
 sodium sulphate (sodium sulphate and distilled water 
 added till the specific gravity is 1-02-5), measured oil' 
 by means of a specially graduated pipette. The 
 contents of the cell are to be well mixed with a little 
 spatula, and then one drop is to be placed in the cell- 
 like depression, with ruled squares of — millimetre 
 each on the floor of the slide, to which springs are 
 attached to secure a cover glass. The slide is then 
 placed in the stage of a microscope, the lens focussed 
 to bring the squares into view. A few minutes are 
 allowed to let the corpuscles sink on to the squares, 
 and then the number contained in 10 squares is 
 counted ; this, multiplied by 10,000, gives the niimber 
 of corpu.'^cles in a cubic millimetre of blood. In the 
 healthy blood of man the standard is 5,000,000 in 
 each cubic millimetre. The depth of colour has now 
 to be determined. To ascertain this two tubes have 
 * Lancet, Dec. 1st, 1877 ; and vol. ii., page 822, 1878. 
 
76 Clinical Chemistry. [Chap. hi. 
 
 to be employed ; the one containing a solution o£ a 
 standard tint, equivalent to the dilution of 20 cubic 
 millemetres of blood in 2 cubic centimetres of water, 
 the other graduated so that 2 cubic centimetres give 
 100 degrees. The tubes are placed side by side, and 
 a sheet of white paper placed behind them. 20 cubic 
 millimetres of blood are then placed in the graduated 
 tube by means of a capillary pipette, a few drops of 
 distilled water being first placed in the bottom of the 
 tube. The mixture is to be kept constantly agitated 
 by a stirring rod. Distilled water is then gradually 
 added until the tint of the diluted blood is exactly 
 the same as that of the standard solution. In healthy 
 blood the tint is reached at 100 degrees of dilution. 
 In blood, poor in hsemogiobin, the degree of dilution 
 required to give the normal tint is less ; so that 60, 
 70, or 80 degrees of dilution only may be required. 
 The result of these two observations is recorded as 
 the value of each corpuscle. Thus the blood from a 
 patient yields 4,000,000 corpuscles for the cubic 
 millimetre, instead of the normal standard, 5,000,000. 
 In other words, the percentage of corpuscles is 80 
 instead of 100, and the amount of dilution required to 
 bring the blood to the standard tint is 60 centimetres, 
 and if we take the percentage of corpuscles as a 
 denominator, and the percentage of colour as a nume- 
 rator, then %% — \ as the vahie of a nominal cor- 
 puscle. The hsemacytometer is also used for deter- 
 mining the proportion of white to red corpuscles. 
 
 (6) Spectrosco'piG characters of hcemoglohin and its 
 comfounds. — Whenever a tube* containing undiluted 
 blood is interposed between a source of light and a 
 spectroscope, the whole of the rays, with the exception 
 of the red, are obscured. On gradually diluting the 
 
 * Or more conveniently a liamatinometer, a vessel with two 
 jjarallel glass faces, one centimetre apart, so that the depth of the 
 stratum examined may be accurately determined. 
 
Chap. III.I 
 
 SfECTRUM OF Blood. 
 
 77 
 
 blood the spectrum cleai-s up, and the red, orange, and 
 yellow become visible, and a portion of the green 
 beyond e. But between D and K there is an intensely 
 dark space. On further dilution this gradually clears 
 up, leaving however two bands (Fig. 1, No. 1), one at 
 a, near to D, with well-detined edges, and whose 
 centre corresponds to 580 — 578 of the wave-line. 
 The other, h, broader, less shaded and defined at the 
 
 Wave line. 
 Oxj-ha-moglubin. 
 
 Reducoil hiBiuOb-lnliin. 
 
 Motliajmnglohin in alka- 
 line solutions. 
 
 Mctlixraoglobin in acid 
 soUuious. 
 
 Reducod lixmatin. 
 
 Hieraitin in alkaline 
 solutions. 
 
 H^inatin in acid solu- 
 tions. 
 
 Fig. 1.— Spectrum of Hsemoglobiu and its Compounds. 
 
 edges, near to E, whose centre corres])onds to 5-40 — 
 543 of the wave-line. The two bands are charac- 
 teristic of oxy-htemoglobin. The space occupied by 
 these bands is a measure of the amount of haemo- 
 globin present. Thus, in a solution one centimetre 
 thick, and containing 8 per cent, htemoglobin, the 
 two bands are continuous from 595 to 520, whilst 
 the green just beyond 518 is slightly visible; by 
 increasing the .strength of the solution the green 
 disappears. With 0-35 per cent, the bands are sepa- 
 rated ; a extends from 588 to 568, and b 55-i to 524. 
 
7 8 Clinical Chemistry. [Chap. hi. 
 
 With 0"09 per cent, solution a extends from 583 — 
 571, and h from 550 — 532, with less than 0-01 per 
 cent, a is faint and extends between 583 and 575, h is 
 visible with difficulty, but Professor Gamgee gives its 
 position as 538 — 550. If we add certain reducing 
 agents to the blood, carefully excluding aii", then the 
 oxy-hsemoglobin is deprived of its oxygen, and we 
 have the spectrum of reduced hcemoglobin ; this gives 
 a single broad band extending from 595 — 540, ditfuse 
 at its edges, and darkest between 560 — 550 (Fig. 1, 
 No. 2). The agent generally used for effecting the re- 
 duction is a solution of stannous chloride, to which 
 a small quantity of tartaric acid is added, and the 
 mixture neutralised with ammonia. When a solution 
 of haemoglobin is exposed for long to the air, or to the 
 action of certain oxydising agents (ozone, potassium 
 permanganate, sodium nitrite, amyl nitrite, etc.) in 
 neutral or faintly alkaline solutions, it forms a 
 yellowish - brown solution, and is converted into 
 methcemoglobin (Fig. 1, Nos. 3 and 4). The nature of 
 this body is not well understood. Formerly it was 
 supposed to be per-oxy-hsemoglobin. It does not, 
 however, form oxy-hsemoglobin under the action of 
 reducing agents, but passes directly into the reduced 
 haemoglobin. This and other considerations have 
 made recent writers view methsemoglobin as contain- 
 ing less oxygen and more iron than oxy-htemogiobin, 
 but that the oxygen is in a more stable condition 
 than in the latter body. In nearly all solutions 
 containing methsemoglobin, the two bands of oxy- 
 hsemoglobin are generally visible. This is accounted 
 for by the presence of a portion of oxy-hsemoglobin 
 not being transformed into methaemoglobin. The 
 fluids of certain cysts, the deposits after the extravasa- 
 tion of blood into the cellular tissue, the blood after 
 inhalations of nitrous oxide, or the administration 
 of the nitrites, and the urine in lisematinuria, give the 
 
Chap. 111.1 II^EMOGLOIilS. 
 
 1') 
 
 cliaractpristic spoctrosoopic appojiranco of motlut'iiio- 
 glohin. When a solution of ha'niOf,'l()bin is treated with 
 acetic acid, the two bands between D and e vani.sh, 
 and instead we have a broad band between c and d, 
 whose centre coiresponds to wave lengtli (i'l^, this the 
 spectrum of acid hcemntin (Fig. 1, No. 6). If the 
 solution be now rendered strongly alkaline, this band 
 shifts nearei" D, with a centre corresponding to GIO of 
 the wave line, whilst the blue end of the spectrum 
 becomes more ob.scure. This is the spectrum of 
 alkaline ho'.matin (Fig. ], No. 6). If to either acid 
 an alkaline solution, the reducing agent (stannous 
 chloride, tartaric acid, and ammonia) be added, no 
 bands are seen in c, D, but in.stead two bands, not 
 unlike those of oxy-hajmoglobin, are seen between D 
 and E, one a broad band reaching from D half way to 
 E, and the other a narrower band near E ; this is the 
 spectrum of reduced hcematin (Fig. 1, No. 7). The 
 spectrum of acid hpematin is not unlike that of methiie- 
 nioglobin in an acid solution, and lias been mistaken 
 for it ; by rendering the sohition alkaline the resem- 
 blance disappears. 
 
 (c) The chemical properties of the colouring matter 
 of the blood. — The detibrinated blood of the rat, 
 squirrel, or guinea-pig, received into a beaker sur- 
 rounded with ice, and allowed to stand a short time, 
 yields abundant and well-detined crystals of htemo- 
 globin, but with the blood of the ox, sheep, horse, or 
 man, the separation in the crystalline form is not so 
 readily obtained, and the following process must be 
 followed : — 100 centimetres of freshly di'awn blood 
 must be rajndly detibrinated and placed in a shallow 
 vessel and treated with ten times its volume of 10 per 
 cent, solution of sodium chloride, and set aside in a 
 cold place (in summer ])laced in a refrigerator) ; when 
 the corpuscles are deposited the supernatant liquid is 
 decanted off, and the mass })laced in a filter and 
 
8o 
 
 Clinic A l C hem is tr v. 
 
 [Chap. III. 
 
 washed repeatedly with sodium chloride sohition till 
 the washings are completely free from albumin. It is 
 then agitated with a mixture of one volume of water 
 to four volumes of ether, and allowed to stand ; the 
 etherial solution contaiiiing the fatty matter is then 
 removed, and the red aqueous solution filtered into a 
 Leaker surrounded with ice, and alcohol carefully 
 added till a precipitate begins to appear. After some^ 
 
 hours crystals of 
 hfemoglobin will 
 form. The success 
 of the proceed- 
 ing depends on 
 thoroughly remov- 
 ing the albumin 
 and fatty matters, 
 and conducting the 
 whole process at a 
 low temperature. 
 The crystals in man 
 form as prismatic 
 needles, with dihedral summits, or in rhombic plates, 
 Fig. 2, c and d. They are soluble in water and alka- 
 line solution, and are insoluble in alcohol, chloroform, 
 and ether. Acids decompose them with the forma- 
 tion of hgematin. 
 
 Ho])pe Seyler gives the composition of dried 
 crystallised haemoglobin as, 
 
 Fig. 2 — Haemoglobin Crystals. 
 A, Of guinea-iiig ; B, of squirrel ; c, D, hiunan. 
 
 c . 
 
 . 54-01 
 
 H . 
 
 . 7-20 
 
 N . 
 
 . 16-17 
 
 Fe . 
 
 •42 
 
 S . 
 
 •72 
 
 . 
 
 . 21-48 
 
 100-00 
 
Chsp. III.) 
 
 HMytOGLOBIN. 
 
 
 from which the fonnula CaooHagoN, 
 
 MFeS,( 
 
 adduced ; and 
 
 
 
 
 
 12 
 
 X 
 
 600 C 
 
 = 
 
 7200 
 
 1 
 
 X 
 
 960 H 
 
 = 
 
 960 
 
 14 
 
 X 
 
 l.n N 
 
 = 
 
 2156 
 
 56 
 
 X 
 
 1 Fe 
 
 = 
 
 56 
 
 32 
 
 X 
 
 3 S 
 
 = 
 
 96 
 
 16 
 
 X 
 
 179 
 
 = 
 
 2864 
 
 8i 
 may be 
 
 13332 
 
 gives the molecular weight 13332. And as one 
 molecule of htenioglobin requires three molecules of 
 soda to form non-coagiilable combinations, therefore 
 ^^^=4444, or the equivalent weight of haemo- 
 globin. 
 
 The amount of oxygen linked with hsemoglobin to 
 form oxy -haemoglobin, is 1"27 cubic centimetres of 
 oxygen at 0'^ C. and 1 metre pressure to 1 gramme of 
 haemoglobin. Carbonic oxide and nitrous oxide dis- 
 place the oxygen in oxy -haemoglobin, the solution ac- 
 quiring a bluish tint, but the spectrum is little altered, 
 and is not atiected by reducing agents, whilst the 
 combination seems more stable than that of oxygen 
 with hemoglobin. Hcemafin C^,H-oNgFe.jO,„ is best 
 prepared by mixing defibrinated blood with a strong 
 solution of potassium carbonate, till the liquid ad- 
 hering to the separated coagulum becomes colourless. 
 The coagulum is then dried at 50' C. and digested for 
 some days in absolute alcohol ; the alcoholic solution 
 after concentration will deposit rhombic crystals. 
 Haematin crystals are of a bluish-black colour with a 
 metallic lustre, becoming brown on trituration. They 
 are insoluble in water, alcohol, ether, and chloroform, 
 but soluble in acids and alkalies ; the acid alcoholic 
 solutions are monochromatic, having a brown colour ; 
 the alkaline solutions are dichromatic, and have an 
 
 G 
 
82 Clinical Chemistry. [Chap. hi. 
 
 olive-green colour and dark red in the thicker layers. 
 The crystals support a temperature of 180° C, but 
 above that they carbonise. When treated with 
 strong sulphuiic acid hsematin is deprived of its iron ; 
 this substance, to which Hoppe Seyler has assigned 
 the name of hceynatojjopiyhyrin (thus, CggH-oNgOnjFe, + 
 4S0,H, + 03 = Ce8H,oN30,o(SO,H,) + 2reS0, + 2H,b), 
 gives to the spectrum a dark band midway between 
 D and E, and a narrow band between c and D 
 (nearer d) ; the spectrum also is deeply shaded 
 between D and e. If a solution of haemoglobin 
 reduced by hydrogen is decomposed by sulphuric 
 acid, a substance is formed which Hoppe Seyler has 
 named hcemocromogen, and which by oxydation yields 
 hsematin. This body when in alkaline solution is 
 identical with reduced haematin, whilst in acid solution 
 its spectrum gives a combination of those of acid hse- 
 matin and hsematopopphyrin. 
 
 Hcemin G^^ -^^ ^^qJJ ^,,C\, or hsematin hydrochlo- 
 ride ; if a small quantity of blood is rubbed iip with 
 sodium chloride and boiled for a few minutes with 
 
 ^ ^jf glacial acetic acid, and the mixture evapo- 
 
 • rated to dryness, in the residue, mixed 
 
 f» i with colourless crystals of sodium chloride 
 
 and sodium acetate, will be found rhombic 
 
 Hffimin^ tablets of hsemin (Fig. 3) ; which are of a 
 Crystals, bluish - red colour when viewed by re- 
 flected, and brownish - red by transmitted, light. 
 They are insoluble in hot and cold water, in 
 alcohol and ether. Soluble in alkaline solutions. 
 All acids, with the exception of hydrochloric and 
 acetic acid, decompose them. Heated to 200° C. 
 they undergo decomposition, evolving fumes of 
 prussic acid, and leaving a residue of oxide of iron. 
 
 Hcematoidin G^^^^^^z (Robin and Verdeil). 
 Under this name Yirchow described certain red 
 ciystals found in clots of old extravasations, as in 
 
Ch;«p. III.) Blood Stains. %i 
 
 a])oplectic clots, corpora lutea, etc. They li.ivt; been 
 considered to be identical with bilirubin, but the 
 question is not yet decided. They can be obtained 
 from the corpora lutea by rubbing them np with 
 j)ounded glass, agitating frofjuently with chloroform. 
 After standing .some time the chloroform solution is 
 poured ofF and allowed to evaporate. The crystals 
 thus obtained are red by transmitted, and green by 
 reflected, light ; they occur in rhombic plates, and 
 •are soluble in chloroform and ether, but insoluble in 
 alcohol, water, and alkali. 
 
 96. Exaiiiiiiatioii of blood stains. — The 
 surface or substance of the material mnst be scraped 
 or cut into small fragments and digested in as little 
 distilled water as possible. Of the reddish fluid 
 examine (1) under microscope for blood corpuscles ; 
 (2) placed in deep narrow cell and examined by a 
 spectroscopic eye-piece with a low power of micro- 
 scope, for bands of haemoglobin ; (3) add a few dro])s 
 of glacial acetic acid and a small quantity of sodium 
 chloride evaporated to dryness at 40° 0. and 50° C, 
 and examine residue for haimin crystals ; (4) place a 
 drachm of tincture of guiacum in a test tube and add 
 a drop of the solution, then float on surface etherial 
 solution of hydrogen peroxide; if blood, a blue I'ing 
 will form at junction of the etherial solution and the 
 guiacum. (N.B. — Other substances besides blood 
 give this reaction with guiacum.) 
 
 97. The colourless corpuscles — These are 
 the white and the intermediate. The former are nu- 
 cleated masses of protoplasm of granular appearance, 
 possessing the power of amreboid movement. They 
 are larger than the red corpuscles, the diameter l)eing 
 77..^^jjth of an inch. The intermediate or hiemato- 
 blasts are smaller than the white corpuscles, and 
 the nucleus is more obscured by granules. Treated 
 with acetic acid the colourless corpuscles swell up, 
 
84 Clinical Chemistry. [Chap. hi. 
 
 rendering the nuclei more distinct. Tonclied with a 
 solution of iodine and potassium iodide, the body of 
 the corpuscles is stained a mahogany-brown, indicating 
 the presence of glycogen. The proportion of white 
 corpuscles to red may be stated as 1 to 340 — 350, 
 but the proportion varies considerably under different 
 physiological conditions, being increased by fasting 
 and diminished by food. In leucocythsemia the pro- 
 portion of white corpuscles to red is greatly increased, 
 so as often to amount to one-eighth or one-tenth of 
 the coloured corpuscles ; they are of the same shajae as 
 in normal blood, but often smaller. On standing, 
 delicate crystals often form in them ; these are sup- 
 posed to be a phosphate of a proteid base. In pro- 
 gressive pernicious anseraia the white corpuscles are 
 not absolutely increased. In addition to the white 
 corpiiscles in leucaemia and pernicious ansemia, there 
 are often nucleated coloured corpuscles similar to 
 those found in the blood of the human embryo ; in these 
 cases the marrow of the bones is generally affected, 
 whether as a primary or secondary condition is still 
 undetermined. 
 
 98. Blood serum, as it separates from 
 coagulated bloodj is clear fluid of a straw colour, sp. 
 gravity 1'025 — 1"028; its alkaline reaction is higher 
 than an equal bulk of blood. It contains, in addition 
 to fatty matters, extractives, and salt, the other pro- 
 teids of the blood, viz., paraglobulin and serum albu- 
 mirL Paraglobulin, serum globulin, or fibrinoplastic 
 substance, is precipitated from blood serum by adding 
 to it magnesium sulphate to complete saturation when 
 it is precipitated. Hammarsten by this method has 
 obtained 3 '103 parts of paraglobulin in 100 parts of 
 blood. It is said to pass easily through animal mem- 
 branes, which serum albumin does not. It is, there- 
 fore, not improbable that some cases of temporary 
 albuminuria may be due to the passage of this body 
 
ciiap. III.) Fatty Matters of Blood. 85 
 
 into the urine, and not altogether to the presence of 
 seruin albumin, as generally Hnp])ose(l. J*ai-agIobulin 
 with lil)rinogen in the presence of the fil)rin feiMnent 
 forms fibrin ; fibrinogen, however, is only found in the 
 blooil plasma. The seruin albitniin can be obtained 
 after the removal of the paraglobulin, by gently con- 
 centrating the filtrate at a low temperature, 30° C, 
 to 35° C, and then placing it on a dialyser to remove 
 saline impurities ; the solution will then give the re- 
 actions described (§ 20). 
 
 99. Fatty inaltei-s. — A definite quantity of 
 blood is evaporated to dryness over a water-bath, and 
 when completely dry the mass is bi'oken up and 
 carefully triturated in a mortar, and the powder 
 thoroughly exhausted with boiling ether. The etherial 
 solution is then evaporated in a weighed ])latinum 
 capsule. The increased weight of the capsule gives 
 the amount of fats in the quantity of blood examined. 
 Normal blood yields from -18 to -2 per cent, of fatty 
 matter, which consists of saponitiable fats, lecithin, 
 and cholesterin, the tvvo latter being chiefly, if not 
 altogether, derived from the corpuscles. To obtain these 
 bodies separately, the residue in the platinum capsule 
 must be again treated with ether and boiled with 
 baryta water ; the fatty acids are thus converted into 
 baryta soap, and can be removed by filtration. The 
 precipitate is then treated with absolute ether, which 
 removes the cholesterin from the soaps, and is evapo- 
 rated on a weighed filter and the amount of cholesterin 
 ascertained. The filtrate is then divided into two por- 
 tions. One is evaporated till it is dry, and is then 
 extracted with absolute alcohol ; the neurin, one of the 
 products of the decomposition of lecithin, is then pie- 
 cipitated by platino-chloride solution, as neurin platino- 
 chloride. The other portion of the filtrate is evaporated 
 to dryness, and fused with sodium hydrate and nitre, 
 and the residue dissolved in water and nitric acid added 
 
86 Clinical Chemistry. [Chap. in. 
 
 in excess ; a solution of ammonium molybdate gives 
 a yellow deposit, which is to be dissolved in ammonia. 
 To this, solution of magnesium sulphate and ammo- 
 nium chloride is added, and on spontaneous evapora- 
 tion crystals of ammonio- magnesium phosphate will 
 form. The ciystals are collected in a platinum capsule, 
 and ignited as directed for the determination of mag- 
 nesia (§ 85). Then since 100 parts of the pyrophosphate 
 are equivalent to 764"8 parts of lecithin, a calculation 
 of the amount of lecithin present can be made. Thus 
 if the weight of the pyrophosphate amounts to "026 
 grammes, then the lecithin will amount to "19764 
 grammes, but as only half the filtrate was taken, then 
 the total lecithin in the fatty residue will be 0-39528, 
 Now supposing the amount of blood examined for 
 fatty matter yielded a residue of total fats of 1'9 per 
 cent. , then by deducting the weight of the cholesterin, 
 which on weighing has been found to be -08 grammes, 
 and deducting the weight of the lecithin as found above, 
 we have the weight of the saponifiable fat. So that 
 100 grammes of blood have yielded 1'9 parts of mixed 
 fats, of which '08 is cholesterin, -395 is lecithin, and 
 the remainder 1'425 saponifiable fat. The amount of 
 fat in the blood is increased after a full meal and 
 diminished during fasting. In diabetes the blood 
 sometimes assumes a lactescent appearance {lijoceinia), 
 due to the presence of excess of fatty matter. This 
 condition, which is rare, is generally met with in cases 
 that have run an acute course, and terminate in a 
 peculiar form of coma. (/S'ee Acetonsemia.) Cholesterin, 
 it is said, is also to be found in excess in the blood in 
 cases of liver disease. {See Cholestersemia. ) 
 
 100. ExtB'actives consist chiefly of urea, glu- 
 cose, kreatin, hypoxanthine, and uric acid. (1) Urea 
 can be determined either (a) by diluting 50 grms. of 
 blood with 200 of distilled water and adding five drops 
 of sulphuric acid, and boiling the mixture. Filter. 
 
cii.ip. III.) ExrnACTivES in Blood. 87 
 
 To tlie (iltr;it(! .'kM a saturated solution of luiiyla 
 liyili'iito (2 voluiiH's) aiiil l)ariuin iiitrati! (I voluiiu;) io 
 throw down sulpliates and })lioKjiliatc.s, and add a 
 few drops of strong solution of silver nitrate 
 to precijjitate chlorid(!S. Filter. Add cautiously to 
 iiltrate some sulj)liuric acid till there is an acid 
 reaction. Filter. Evai)orate filtrate to consistence of 
 syrup, and add 50 cc. of absolute alcoliol. Filter. 
 Evaporate alcoholic solution and dissolve residue in 
 50 cc. of water. To this add cautiously from a Mohr's 
 burette, drop by drop, Liebig's solution of mercuric 
 niti'ato (see Urine, § 110), diluted with an equal quantity 
 of distilled water, stirring after each addition, and 
 removing a drop of the mixture to a plaster of Paris 
 slab moistened with drops of sodic carbonate solu- 
 tion. When a yellow stain is given to one of these 
 droi)s, no more mercuric solution is to be added. As 
 1 cc. of tlie mercuric solution is equivalent to 
 •005 gramme of urea, the number of centimetres of 
 the solution used indicates the amount of urea in 
 50 cc. of blood, {b) Detibrinate* 20 cc. of blood, 
 place it on a parchment jaaper dialyser, and spread it 
 over it so as to foiin a thin layer. Float it in a 
 vessel containing 50 cc. of absolute alcohol. From 
 time to time add a very little distilled water to keep 
 the mass on dialyser moist ; continue the process for 
 twelve hours. Treat the diffusate with an equal 
 bulk of solution of concentrated oxalic acid, and 
 evaporate to dryness. To residue add some naphtha 
 petroleum to i*emove fatty matters. Dissolve the 
 purified residue in a little water, and add barium car- 
 bonate. Eva|)orate. Treat tlie residue with boiling 
 alcohol and filter. Concentrate filtrate, from winch 
 on cooling urea will crystallise out. The pei'centage 
 amount of urea in healthy blood ranges from '025 to 
 •035 grras. In Bright's disease, acute yellow atrophy 
 * Uayci'aft's method, from Professor Gamgce's work. 
 
88 Clinical Chemistry. [Chap. iii. 
 
 of the liver, and in gout, the amount is considerably- 
 increased. 
 
 (2) Glucose. Dr. Pavy's process gives the most 
 reliable results hitherto obtained. It is as follows :— 
 Forty grammes of sulphate of soda in small 
 crystals are weighed out in a beaker of about 200 cc. 
 capacity. About 20 cc. of the blood intended for 
 analysis is then poured upon the crystals, and the 
 beaker and its contents again carefully weighed. The 
 blood and crystals are well stirred together with a 
 glass rod, and about 30 cc. of a hot concentrated solu- 
 tion of sulphate of soda added. The beaker is placed 
 over a flame guarded with wire gauze, and the contents 
 heated until a thoroughly formed coagulum is seen to 
 be suspended in a clear colourless liquid ; to attain 
 which actual boiling for a short time is required. The 
 liquid has now to be separated from the coagulum, and 
 the latter washed to remove all the sugar. This is 
 done by first pouring off the liquid through a piece of 
 muslin resting in a funnel into another beaker of 
 rather larger capacity. Some of the hot concentrated 
 solution of sulphate of soda is then poured on the 
 coagulum, well stirred up with it, and the whole 
 thrown on the piece of muslin. By squeezing, the 
 liquid is expressed; and to secure that no sugar is left 
 behind, the coagulum is returned to the beaker, 
 and the process of washing and squeezing repeated. 
 The liquid thus obtained may be fairly regarded 
 as containing all the sugar that existed in the blood. 
 From the coarse kind of filtration and squeezing 
 employed, it is slightly turbid, and requires to be 
 thoroughly boiled to prepare it for filtration through 
 ordinary filter-paper. A perfectly clear liquid runs 
 through, and to complete this part of the operation 
 the beaker that has been used, and the filter-paper, are 
 washed with some of the concentrated solution of 
 sulphate of soda before referred to. 
 
Chap. III.) Sugar in Blood. 89 
 
 The next step is boiling with tlie copper-test solu- 
 tion. The liquid is aguiu placed over a flame, and 
 broufjfht to a state of ebullition. A suiHcient quantity 
 of the cojjper solution to leave some in excess is now 
 poured in, and, from the time of i-ecommencement of 
 boiling, brisk ebullition is allowed to continue for a 
 period of one minute. As regards the amount of 
 copper solution to be used, although 10 cc. of the 
 test, as ordinarily made, are found to suttice for 20 cc. 
 of the blood of animals in a natural state, yet it is 
 well to employ from 20 to 30 cc. to secure that it is 
 thoroughly in excess. Where, from any circum- 
 stance, larger quantities of sugar exist in the blood, 
 more in proportion of the test must, of course, be used. 
 
 The precipitated suboxide of copper has now to 
 be separated fi'om the excess of copper solution. 
 Experience shows that filti-ation through tilter-paper 
 cannot be resorted to for the purpose. A material, 
 however, which has somewhat recently been intro- 
 duced, viz., glass-wool, fully furnishes what is wanted. 
 Properly packed in the neck of a funnel, it permits 
 filtration to be efiectively and easily performed. The 
 filtrate should always be carefully examined, to see if 
 the plug has been sufficiently tightly packed to keep 
 the whole of the precipitate back. Should the 
 crystallisation of the sulphate of soda in this or the 
 preceding tiltration interfere with the continuance of 
 the operation, the funnel may be placed over a beaker 
 holding some liquor kept in a state of ebullition, or 
 heat may be applied in any other way. 
 
 The suboxide having been collected, and washing 
 with distilled water performed, it is retui-ned to the 
 beaker in which the reduction was etFected, to secure 
 that none of the precipitate that may have been 
 adhering to the sides of the vessel is lost. The plug 
 is pushed with a glass I'od from the neck of the 
 funnel held in an inverted position over the beaker, 
 
90 Clinical Chemistry. [Chap. iii. 
 
 and the funnel washed and its surface cleaned from 
 all adhering precipitate. Now the suboxide is in a 
 fit state to dissolve, and, after the addition of a few 
 drops of peroxide of hydrogen, a very small quantity 
 of nitric acid (a few drops only) is sufficient to lead 
 to instantaneous solution, and, after boiling, to decom- 
 pose the excess of peroxide of hydrogen, the contents 
 of the beaker, consisting of filter-plug and dissolved 
 precipitate, are poured into a funnel containing a 
 loose plug of glass-wool, to obtain the liquid in a 
 separate form. The requisite washing with distilled 
 water having been performed, there only remains the 
 final stage of the process to be accomplished. 
 
 The liquid to be now dealt with contains the 
 copper in the form of nitrate, which experiment has 
 shown to be the most suitable for yielding a pure 
 metallic deposit by galvanic action. For the purpose 
 of collecting the deposit, a cylinder of platinum foil, 
 soldered to a platinum wire for hooking on to the 
 negative pole of the battery, is employed. This is 
 immersed in the liquid so as nearly to touch the 
 bottom of the vessel, and inserted within it is a spiral 
 coil of platinum wire, made to constitute the positive 
 pole of the battery. In order to secure a good con- 
 tinuous connection, the platinum spiral is closely 
 bound to the copper conducting- wire of the battery, 
 and the other pole is provided with a platinum hook 
 for the suspension of the cylinder. At the end of 
 twenty-four hours' exposure to galvanic action the 
 weight of the cylinder with the deposited coj)per is 
 taken. The cylinder is lifted quickly out of the 
 liquid, and instantly plunged, first into distilled 
 water, and then into spirit, the latter being used to 
 avoid the occurrence of oxydation of the copper in 
 drying. After drying by suspension in a water- 
 oven, the process of weighing is performed, and it is 
 hardly necessary to say that a delicate chemical 
 
Chap. m.| See Ah' IN Blood. 91 
 
 lialance is required for tlie purpose. The weight of 
 the cylinder boini^ known and subtracted gives the 
 woiglit of the copper that lias been thrown down. Jn 
 the case of an analysis of blood containing an 
 ordinary amount of sugar, and therefore yielding a 
 liniiteil amount of copper to be deposited, twenty- 
 four hours have usually been found to suffice for the 
 completion of the oi)eration ; but it is necessary there 
 should be no uncertainty upon this point, and, to 
 secure this, the following course of procedure should 
 be adopted. After the weighing has been etlected, 
 the deposited copi)er is dissolved ofl' by immersion of 
 the cylinder in nitric acid, and the cylinder then 
 returned into the liquid to see if any fresh deposit 
 occurs. If, after some hours, no copper tint is seen, 
 the operation may be regarded as completed ; but, if 
 more deposit has occurred, the immersion must be 
 continued, and another -weighing performed, and this 
 repeated till the platinum sui-face remains untinted. 
 
 The galvanic action requii'es to be steadily and 
 continuously maintained, and a modification of Fullei's 
 mercury-bichromate battery has been found to answer 
 best for use. The arrangement that was employed 
 in Dr. Pavy's experiments consisted of an outer cell 
 provided with two carbon plates, and charged with bi- 
 chromate of potash dissolved to saturation in dilute sul- 
 phuric acid. Into the inner porous cell a little mercury 
 is poured, and it is then filled up with water. An 
 amalgamated zinc rod is inserted, and dips down into 
 the layer of mercury at the bottom. This battei'y, it 
 is found, gives a steady current, and, used every day, 
 will remain in good working order for at least a 
 fortnight, all that is necessary being to poiir out the 
 liquid in the porous cell when it has become green 
 from reduction of the ditiused biehi'omate solution, 
 and replace it with water. Attention is, of course, 
 necessary to secure that the proper battery -power 
 
92 Clinical Chemistry. [Chap. in. 
 
 exists to effect the deposition of the copper, and, when 
 the current becomes weak, the zinc rod must be cleaned, 
 and the bichromate of potash solution replenished. 
 
 When sugar is boiled with the copper solution, 
 the change occurring stands in the relation of one 
 atom of the foi'mer to five atoms of cupric oxide. 
 One atom of sugar is oxydised by, or reduces, five 
 atoms of cupric oxide. This is the foundation of the 
 action involved in the operation of the test, and the 
 calculation of the amount of sugar present is made 
 accordingly. Taking 634 as the atomic weight of 
 copper, and 180 as that of glucose CgHijOg, 317 
 parts of copper will stand equivalent to 180 parts of 
 glucose. Thus, one part of copper corresponds to '5678 
 of glucose, and, in calculating the amoimt of sugar in 
 the blood analysed, the weight of the copper deposited 
 has only to be multiplied by '5678 to give its 
 equivalent in glucose. The quantity of sugar in the 
 amount of blood taken for analysis being thus deter- 
 mined, the required information is supplied for 
 expressing the proportion for 1000 parts. 
 
 (3) Kreatin is found in only very small quantities 
 in blood. In order, therefore, to obtain it in any 
 appreciable amount, large quantities of blood are 
 required for analysis. Take 1000 grms. of blood, 
 and remove albuminous constituents, phosphates, sul- 
 phates, and chlorides, as described for the determina- 
 tion of urea. The clear filtrate is then precipitated 
 by a solution of basic lead acetate. Filter. The 
 filtrate is then decomposed by sulphuretted hydrogen 
 to remove the lead, and filtered through animal 
 charcoal. The filtrate is then evaporated gently to a 
 syrupy consistence, and treated with twice its volume 
 with alcohol, from which mixture crystals of kreatin 
 (§ 62) will deposit. [The student who wishes to 
 obtain kreatin as a specimen can readily obtain it 
 by dissolving 5 grms. of meat extract in 50 cubic 
 
ciiap. 1 1 I.I Salts of Blood. 93 
 
 centimetres of water, adding basic lead acetate, and 
 proceeding with the filtrate as directed above.] 
 
 (4) Ilypoxanthin is found in the juice of flesh, in 
 the s[)loon, and in the thymus and thyroid glands. Jn 
 loucocytluvmia it is found in appreciable quantities in 
 the blood. To determine it, take 100 grms. of blood, 
 and separate the albuminous constituent, the phosphate 
 sulphate, and chlorides. The aqueous solution is 
 then treated with ammoniacal solution of silver 
 nitrate, as directed. (.See Urine, § 125.) 
 
 (5) Uric acid cannot be obtained from healthy 
 lilood in quantities suflicient for identification. In 
 gout, however, this suljstance can be obtained for 
 examination by placing about two drachms of serum 
 (ol)tained from a blister) in a large watch-glass, and 
 adding to it, by means of a glass rod, acetic acid 
 till it has a decided acid reaction. Place in the mix- 
 ture a fibre of coarse linen, and allow it to stand till 
 the contents of the watch-glass become gelatinous ; 
 then take out the fibre, and crystals of uric acid will 
 be found adhering to it (§ 111 ). 
 
 101. Salts. — The inorganic residue of blood is 
 generally determined by incinerating a gi\'en quantity 
 of blood in a muffle furnace, or over a Bunsen lamp, till 
 tlie ash is nearly colourless, and making a quantitative 
 estimation of the acids and bases present. This 
 method is sufficiently accurate when we wish to deter- 
 mine only the bases ; but, in the case of the phosphates 
 and sulphates, it is liable to error, since the phos- 
 phorus contained in the phosphorised fats, and the 
 suljihur from the proteids, become oxydised^ and com- 
 bines with the bases. It is therefore best to calculate 
 the bases directly from the ash, according to directions 
 §§ 8.5 and 88, and make a separate detei'mination of 
 the acids directly from the blood. This can be done 
 by placing a small quantity of blood, dried at a low 
 temperature and completely pulverised, and then 
 
94 Clinical Chemistry. [Cnap. in. 
 
 moistened with water, on a clialysei% and floatinof it in 
 a small quantity of distilled water, till what comes 
 froin the dialyser when placed in a fresh quantity of 
 distilled water no longer gives a haze with solution of 
 silver nitrate. The diffusate contains both the 
 oxydised and unoxydised inorganic residue, and the 
 former can be calculated volumetrically by the pro- 
 cesses given for the estimation of phosphoric acid 
 (§ 113), hydrochloric acid (§ 114), and sulphuric acid 
 (§ 115). [See Urine.) An analysis so conducted 
 yielded the following results : 100 parts of blood the 
 ash yielded, lime, "Oil ; magnesia, -006 ; potash, -034 ; 
 soda, "374; iron oxide, -045; phosphoric acid, -112; 
 sulphuric acid, "035 ; hydrochloric acid, -285. This 
 analysis shows the preponderance of soda over potash, 
 a preponderance which is still more marked if only 
 the serum be taken for analysis. On the other hand, 
 the potassium salts are more abundant in the cor- 
 puscles (§ 10). The chlorides, again, are more abun- 
 dant in the serum, the phosphates in the corpuscles. 
 "With regard to the combination existing between the 
 bases and the acids, the soda combines with chlorine 
 to form 0-53 per cent, of the ash, and with phos- 
 phoric acid as neutral phosphate Na2HP04, whilst 
 •15 2^arts of soda are combined with carbonic acid as 
 normal carbonate NajHCOs, and as acid carbonate 
 NaHaCOg. It is owing to the decomposition re- 
 sulting between the neutral phosphate of soda and the 
 acid carbonate that acid secretions are separated from 
 the alkaline blood (§ 9), a fact I showed experi- 
 mentally in 1874,* and which has subsequently been 
 confirmed by other observers. The phosphoric acid 
 is chiefly combined with potash in the corpuscles, and 
 with lime and soda in the serum. 
 
 102. Toxic conditions of the Mood.— When 
 any impediment is offered to the excretion of the 
 * Lancet, July, 1874. 
 
Chap. III. 1 AsriiYXiA. 95 
 
 effete materials of Ww. organism by the natural chan- 
 nels, thnsc accumulate in the blood, and induce symp- 
 toms of great gravity. When, for instance, the process 
 of aeration of the blood by means of the lungs is 
 checked to any great extent, carV)onic acid accumulates 
 in the lihiod.and the condition of nspltyxia is induced. 
 This, when the blockage of the air-jKissages is com- 
 plete, proves rapidly fatal. In less severe forms of 
 obstruction, the condition is marked by dyspncea, and 
 a more or less livid and purplish condition (n/rniosis) 
 of the skin and visible nnicous membranes, due to the 
 presence of imperfectly aerated blood in the capillaries. 
 Cyanosis is the most conspicuous symptom of con- 
 genital deformity of the heart. Insufficiency of the 
 tricuspid valve, causing as it does great engorgement 
 of the veins of the systemic circulation, is generally 
 accompanied by marked cyanosis. In emphysema, 
 especially in the later stages, when the right side of 
 the heart ceases to compensate by its hypertrophy for 
 the circulatory impediment, the cyanosis becomes ex- 
 tremely intense ; even in the early stages, with the 
 loss of the interalveolar septa and disappearance of the 
 capillaries, the imperfect aei'ation of the blood is 
 manifest in the leaden hue of the patient's countenance. 
 In disease affecting the left side of the heart, cyanosis 
 is not a marked symptom. Niemeyer ingeniously ac- 
 counts for this by the su])position that in valvular affec- 
 tions of the left heart the pulmonary circulation is sur- 
 charged with blood, whilst the quantity of blood in 
 the systemic circulation is abnormally small ; whilst 
 in emphysema, whei'e many pulmonary capillaries have 
 perished, and in diseases of the tricuspid and pul- 
 monary valves, it is the systemic circulation which is 
 o\'erloaded, whilst the pulmonary contains too little 
 blood for effectual aeration. In diseases accompanied 
 by diminution in the number and colour v.due of the 
 red corpuscles, in addition to the pallor, there is 
 
96 Clinical Chemistry. [Chap. in. 
 
 usually a well-marked leaden hue ; this is particularly 
 noticeable in patients suffering from scurvy. 
 
 In diseases of the kidney, when the excretion of the 
 solid matters of the urine is considerably diminished, 
 a condition known as urcsinia often supervenes. This 
 is generally attended by a drowsy condition, more or 
 less intense, with the frequent recurrence of convul- 
 sions of an epileptic character. The urine is greatly 
 diminished ; but if it should be increased, as it is in 
 some rare cases, it is of very low specific gravity. 
 Numerous views have been advanced to account for 
 the symptom. Some consider it due to the poisonous 
 action per se of retained urea ; others, that the urea 
 is decomposed into ammonium carbonate, and the 
 blood is poisoned with ammonia ; while others hold 
 that excess of urea in the blood causes the water of 
 that fluid more readily to transude through the capil- 
 laries, and thus cause oedema of the brain. Against 
 these views it maybe urged that urea may be injected 
 in large quantities into the veins of animals without 
 inducing ursemia; that no ammoniacal odour is percep- 
 tible in the health of persons suffering from this 
 condition, whilst in typhus fever, in which ammonia 
 has been recognised in the breath by many reliable 
 observers, the coma is not of urjemic character. And 
 lastly, ureemic convulsions occur in some cases without 
 there being evidence of any marked diminution in the 
 excretion of urea, as in puerperal convulsions. In 
 this condition a considerable quantity of albumin is 
 passed in to the urine, amounting, in three examina- 
 tions I have made, from six to eleven grms. in the 
 twenty-four hours ; the urea, on the other hand, was 
 only slightly below the normal rate of excretion. Con- 
 sidering ureemic convulsions occur chiefly in cases 
 where the drain of albumiai has been considerable, 
 either in large quantities as in acute nephritis, or in 
 small quantities but of long continuance, as in chronic 
 
Chap. III.] Ur.-emia. 97 
 
 renal disease, I tliink we may reasonably attribute 
 the condition in some measure to the withdrawal of 
 the nutritive matter of tlie blood, or, at least, to the 
 altered percentage relationship between it and the 
 effete (extractive) materials. One point is clear, that 
 venesection often proves of immense service in this 
 condition, - apparently by altering the percentage 
 comi)osition. In one case of uraemic convulsions, 
 in a lady seven months advanced in pregnancy, Avhose 
 urine I examined at the request of Dr. John Williams, 
 I found in the urine passed during twelve hours 
 immediately preceding Aenesection, 5"1 grammes of 
 albumin, whilst the urine passed in the twelve hours 
 immediately after venesection only contained 2-3 
 grammes. Free purgation, by relieving the tension 
 in the renal capillaries, has much the same etlect, 
 though to a less extent. A patient in a state of 
 deep coma, which had been preceded by convul- 
 sions, had a drop of croton oil administered, his 
 urine at the time containing about one-fifth albu- 
 min ; after free purgation he recovered conscious- 
 ness for several hours and the urine was found on 
 examination to contain only one-twelfth albumin. 
 
 In diseases of the liver, when any obstruction is 
 offered to the onward passage of the bile, re-absorption 
 takes place, and the bile passes into the blood and is 
 deposited in the tissues, giving rise to the phenomenon 
 of jaundice. (See Bile, chapter v.) 
 
 In certain forms of liver disease, particulai'ly 
 cirrhosis, in which there is a great destruction of 
 liver cells, the termination is by coma, and has been 
 attributed to the retention of cholesterin in the 
 blood {cholesteriemia) . We have no evidence, how- 
 ever, to show that cholesterin has any toxic influ- 
 ence. Krusenstern injected from 'OOo to '045 gramme 
 of cholesterin daily into the veins of dogs, and found 
 the animals unafl'ected. Pag^s arrived at the samj 
 
 H . 
 
98 Clinical Chemistry. [Chap. iii. 
 
 results. * Looking at the question from the purely clini- 
 cal side, one would expect cholestersemia in all cases of 
 jaundice where there was considerable resorption of 
 bile. If the liver is the seat, as is generally held, of 
 the destruction of the blood corpuscles, which contain 
 nearly all the cholesterin found in the blood in. the 
 normal state, we may naturally suppose the cholesterin 
 of the bile re-absorbed in a free state into the blood, 
 would rapidly induce cholestersemia; but, as a matter of 
 fact, the phenomena attendant of this condition are 
 not common to jaundice, due simply to obstructions, 
 however complete, unless there be also considerable 
 destruction of liver tissue and disease of the kidneys. 
 Again, in acute yellow atrophy, where we have rapid 
 destruction of the liver cells, and where jaundice is com- 
 paratively slight, the coma is preceded and attended 
 with symptoms much resembling those witnessed wlien 
 acids, or phosphorus, are injected into the veins of 
 animals, or in patients dying from acute diabetic coma 
 (acetonsemia). From these considerations I venture to 
 think that the coma attendant upon hepatic disease in 
 which there is considerable destruction of liver cells, is 
 not due to the accumulation of cholesterin, which, in 
 many cases of ordinary jaundice, increases four or five 
 per cent. (Frerichs) without inducing the condition, but 
 to a general increase of the excretory matters in the 
 blood, and this supposition is strengthened by the fact 
 that the condition is never witnessed iinless there is 
 also some impairment as well of the renal functions. 
 
 In diabetic urine there is often found a body that 
 gives with ferric chloride a deep red reaction, and cor- 
 responds, in many respects, with acetone, or acetone- 
 yielding bodies. As this substance has been found 
 most frequentlyt in the urine of patients dying rapidly 
 
 * Journal de VAnatomie et de la Physiologie, 1875. 
 t Acetone can be obtained from most diabetic urines by dis- 
 tillation with hydrochloric acid. 
 
Chap. III.) ACETON^EI^IIA. 99 
 
 of acute clial)etic coma, it has been supposed that this 
 phenomena is due to the presence of acetone in the 
 blood (acetoncemia). Fi-ee acetone, however, has not, 
 I believe, ever been obtained in a free state from 
 fioshly-drawn diabetic blood, but there is little doubt 
 that a body readily yielding acetone can be separated 
 from the blood of such patients. The nature of this 
 body is a matter of some dispute ; most writers consider 
 it to be ethyl diacetate, Avhich, by decomposition, 
 yields equal molecules of acetone and alcohol. In this 
 case, by distillation we ought to obtain equal amounts 
 of acetone and alrohol ; indeed, as acetone is the most 
 volatile, it should be found in less amount. Some 
 recent observations,* however, have shown, on the con- 
 trary, that when diabetic uj-ine is distilled, the acetone 
 is considerably in excess of the alcohol, and hence it 
 has been surmised that the body is some compound of 
 aceto-acetic acid. When acetone, or the acetone- 
 yielding body, is found in the urine, there is as Avell a 
 ])eculiar odour, like that of acetone, exhaled by the 
 breath, and the urine likewise. This odour is gene- 
 rally particularly noticed as preceding acute diabetic 
 coma, though when that condition is thoroughly esta- 
 blished, it often disappears. After death, a lactes- 
 cent or milky appearance is sometimes noted, with 
 fatty changes of the liver and otlier viscera, though 
 these conditions are far from being invariable. Acute 
 diabetic coma or acetontemia is distinguished from 
 the more common but less characteristic form of coma, 
 which usually tei-minates the disease, in the sudden- 
 ness of its onset, the gastric disturbance, as shown by 
 the acute epigastric pain, the vomiting (sometimes of 
 blood), and more rarely, frequent purging ; the pecu- 
 liar noisy delirium, the panting respiration like an 
 animal with both vagi cut, the fluctuations in the 
 
 * Deicbmuller, Annalen, 209, 22—30. B. Tollens, Annalen, 209, 
 30—38. 
 
loo Clinical Chemistry, [Chap. hi. 
 
 rapidity of the pulse, which maintain till the coma is 
 well established, when the pulse continues intensely 
 rapid and small. These are symptoms which come 
 on in rapid succession, and present a parallel to 
 those which occur in acute yellow atrophy and phos- 
 phorus poisoning, or the injection of the bile acids 
 or mineral acids into the blood of animals. The origin 
 of the acetone-yielding body has not been determined, 
 but it is probable that it is derived from some meta- 
 morphosis of the sugar in the blood, forming alcohol 
 and the products of alcoholic fermentation. When 
 we consider the highly acid character of the urine in 
 diabetes, and the fact that symptoms of acute diabetic 
 coma are not unlike those produced in animals 
 poisoned by the injection of acid into their veins, it is 
 not improbable that the body concerned is of an acid 
 nature — aceto-acetic acid, as has been suggested. This 
 body is probably present in the blood of most diabetics, 
 in small quantities, and by its elimination from the 
 urine gives that secretion the highly acid reaction met 
 with in diabetes. When, however, it is formed in 
 excessive quantities, or its elimination is interfered 
 Avith, it accumulates in the blood, giving )-ise to the 
 condition known as acetonsemia. The presence of 
 acetone, or the acetone-yielding body, can be demon- 
 strated in urine by the deep red coloration given by 
 ferric chloride, which disappears on the addition of 
 hydrochloric acid, and by the reaction with iodide of 
 potassium. This last I have endeavoured to make 
 available as a clinical test, as follows ; About a drachm 
 of liquor potassoe, containing twenty grains of iodide of 
 potassium, is placed in a test tube and boiled ; a 
 drachm of the suspected urine is then carefully floated 
 on the surface. Where the urine comes in contact 
 with the hot alkaline solution, a ring of phosphates is 
 formed, and after a few minutes, if acetone or its allies 
 are \)resent, the ring will become yellow, and studded 
 
cii.ip. iii.i CiiVLi-: AND T.VMrir. loi 
 
 \\'\\\\ j-fUow points of ioiloffiiiii ; (licsc in (iiiio will sink 
 thi-oii^rh (lio liiiLf of plioK])liiit('S, jiikI iieconio dei)ositc(| 
 at tlio hottom of the test tube. 
 
 10;5. Chyle siekI lyinB»li. — In examining tlicsf; 
 fluids the same steps arc to be taken as in the examina- 
 tion of blood, and the same methods cm[)loyed for the 
 determination of (ho specific gravity, the reaction, the 
 amount of librin and other proteids, the fatty mattei", 
 the extractives, and the salts. The chyle derived frcjm 
 the intestinal lacteals does not contain fibrin, and 
 consequently does not separate into clot and serum. 
 If the animal has l)een fasting, the chyle loses its creamy 
 appearance and becomes more transparent and of a 
 yellowish colour. 100 pai-ts of chyle yield, when 
 taken from the lacteals in full digestion : water, 91'8 ; 
 solids, 8 "2; librin, 0-2; proteids, 3 '5; fats, 3-3; extrac- 
 tives, 0'4; salts, 0'8; when fasting: water, 9G'8; solids, 
 •38; fibrin, -09; proteids, 2'30; fat, "04; extractives, 
 •28; salts, •49. The proteids consist of serum albumin, 
 paraglobulin, fibrinogen, and peptones. The fatty 
 matters, which consist of minute spherical globules, 
 and form what Gulliver called the molecular base of 
 the chyle, are a mixture of saponifiable fats, cliolcs- 
 terin, and lecithin (100 parts of ether extract yield 
 81^ saponifiable fat; 7^5 parts lecithin; 11'3 parts 
 cholesterin ; Hoppe Seyler). The extractives are urea, 
 and glucose, whilst leucin and tyrosin are frequently 
 obtained. The constitution of the ash resembles that 
 of the blood, the sodium having a prepondei-ance over 
 the potassium salts. Lympli is a clear, colourless, or 
 straw-coloured fluid, of sliglitly alkaline reaction. In 
 composition lymph closely resembles chyle, differing 
 chiefl}'- in the smaller proportion of fibrin and fatty 
 matters it contains. 
 
 104. Milli. — The following gives the average 
 composition of human milk in 100 parts: water, 86^86; 
 solids, 13-2; proteids (chiefly casein) 2-93, butter 3'78, 
 
I02 . Clinical Chemistry. [Chap. hi. 
 
 sugar of milk 5 '83, extractives 0'25, salts 0"35. 
 It varies, however, considerably with the character of 
 the food and other physiological conditions. Of the 
 constituents, however, the casein and sugar are the 
 most constant, whilst the fatty matters show a wide 
 range of variability. Analyses have shown that the 
 composition of milk varies with the age of the infant. 
 Thus the casein is at its lowest at the commencement 
 of suckling, and then gradually rises till it attains a 
 fixed proportion, whilst the sugar is at its maximum 
 at the commencement and subsequently diminishes. 
 This is important in relation to the artificial feeding 
 of infants. A comparison of human milk with cows' 
 milk shows that the latter contains more casein but less 
 sugar, whilst asses' milk, though poorer in casein than 
 human milk, is quite as rich in sugar. The colostruvi 
 or the milk, passed during the first week after delivery, 
 has a more alkaline reaction and higher specific 
 gravity than ordinary milk, and is richer in casein and 
 fatty matters. In certain morbid conditions the 
 composition of the milk may be altered, though 
 observations on this point are much wanting. In 
 pyrexia the secretion is diminished, or may be quite 
 suppressed, and the quantity of solids, chiefly the fats 
 and sugar, fall considerably. After undue excitement, 
 shock, mental emotion, the milk has been noticed to 
 have an acid reaction, or to become so shortly after 
 secretion. In some cases rapid decomposition sets in 
 with the evolution of sulphuretted hydrogen. Certain 
 substances taken as food or medicine find their way into 
 the mammary secretion and for a time render it unfit 
 for use. During the latter stage of pregnancy and the 
 earlier period of lactation sugar sometimes appears in 
 the urine; this must not be confounded with the grape 
 sugar of true diabetes, but is the milk sugar, lactose 
 (F. Hofmeister "Ueber Lactosurie, Zeitsch. f. Phys. 
 Chem." i. § 101), and can be distinguished by its 
 
ciiap. IV.) Milk. 103 
 
 pliysical iind chemical characters (§ 13). Milk some- 
 times assumes a distinctly Mue ajJiK-araiice; this is duo 
 to the development of bacteria. When milk is added 
 to an artilicial solution of gastiic juice it becomes 
 curdled, and this curd is gradually dissolved as diges- 
 tion proceeds. This curdling is not due to the acid of 
 the gastric juice, but to some ferment which sets 
 up lactic acid fermentation in the milk sugar, as 
 is evident by the fact that if the artificial juice is 
 neutralised before the addition of the milk, the 
 curdling takes place just the same. The specific 
 gravity of the milk and its alkaline reaction are 
 determined by the same methods as described for 
 blood. The casein is separated by adding a few drops 
 of acetic acid, and boiling. Collecting the curd and 
 drying it, rubbing up the dried residue in a glass 
 mortar and frequently extracting with ether to remove 
 the fatty matter ; placing the purified residue on a 
 weighed filter and drying it. The fatty matter, 
 extractives, and salts are determined as directed for 
 blood. The lactose can be obtained as directed by 
 Pavy's method for separating glucose from blood, or 
 can be estimated directly by Fehling's process (see 
 Urine), after the milk has been freed from albumin. 
 
 CHAPTER IV. 
 
 MORBID CONDITION'S OF URINE. 
 
 105. Examination of morbid urine. — In 
 
 order to draw conclusive results fi'om the examination 
 of urine in disease, a systematic plan of procedure must 
 be adopted and the circumstances and conditions 
 under which the secretion was passed precisely stated. 
 
T04 Clinical Chemistry. [Char. iv. 
 
 The neglect of ttese precautions i-enders many investi- 
 gations valueless, whilst in some instances it leads to 
 erroneous conclusions being drawn. As is well known, 
 the specific gravity, the reaction, and proportionate 
 relationship of the different constituents of the urine, 
 even in health, vary considerably during different 
 periods of the day, whilst in disease such variations 
 are still more considerable. It is evident, therefore, 
 if v/e wish to arrive at a right conclusion as to the 
 nature of the pathological condition with which we 
 have to deal, our observations must be based upon an 
 examination of the Avhole of the urine passed during a 
 period of twenty-four hours. If that is not always 
 possible, from at least two samples ; the one taken on 
 first rising in the morning, the other two hours after 
 the principal meal of the day. No definite conclusion 
 sliould eve'^ be drawn from the exaviination of a single 
 sam,ple of tirine jjassed within tioenty hours. In noting 
 the character and qualities of urine in disease the 
 following scheme may advantageously be followed : 
 (1) State the circumstances under which the urine 
 was passed ; whether it represents the secretion of the 
 twenty-four hours, or is only a specimen passed at 
 some period diiring the day; if the latter, state the 
 time when voided. (2) Record the quantity presented 
 for examination (if the twenty-four hours' urine has 
 been collected, give the amount), the sjDecific gravity 
 and reaction, note also its colour and odour and 
 degree of clearness. (3) Test for abnormal products, 
 sugar, albumin, etc. (4) Collect deposit for chemical 
 and microscopic examination. This procedure will 
 give us an insight into the qualitative changes that 
 occur from day to day in the character of urine during 
 the progress of disease. To determine the quantitative 
 changes in the amount of the urinary constituents two 
 methods are employed : (1) Exact chemical determina- 
 tion, which consists either in precipitating, collecting, 
 
Chnp. IV.l 
 
 Srr.ciFic Gr a vi t j '. 
 
 ^05 
 
 and then weighing the precipitated substance (the 
 "gravimetric metliod"); or by precipitating or other- 
 wise altering the substa,nce by means of a solution 
 of a reagent of known strength, or ascertaining tlie 
 quantity of the reagent required to efl'ect a complete 
 change; this is tlie "volumetric method." (2) ylpproxi- 
 mnte estimntioih by some ready means and easily 
 applied clinical motliod, such as calculating the amount 
 of urinary solids from the spocitic gravity, or the 
 quantity of sugar by the loss of weight occasioned by 
 fermentation with yeast, or by the degree of intensity of 
 colour wiien compared with a standard of comparison. 
 Approximate estimation, however useful, should never 
 be entirely relied on. Exact chemical determinations 
 should always be made from time to time. In all 
 cases the calculation should be made from the urine 
 passed in a period of twenty-four hours ; in this way 
 we get the absolute as well as the relative amount of 
 the substances passing out of the body during this 
 period. 
 
 106. Tariatioti in the urinary water and 
 solids. — Specific |!:i'avity. — The following table 
 gives apjiroximately the amount of the chief consti- 
 tuents of the twenty-four hours' urine, in a child, a 
 irrowinir lad, and an adult. 
 
 JIeax Amoint Chief CoxsTiTrEXTs of Normal HuMAxIJRryE 
 PASSED IX Twenty-four Hours. 
 
 
 5 years 
 
 12 vpars 
 
 35 years 
 
 
 weight 37J lbs. 
 
 weight 64i lbs. 
 
 weight 14-7 lbs. 
 
 Water . 
 
 450 cc. 
 
 860 cc. 
 
 1,4')0 CO. 
 
 Urea 
 
 11-1 gniis. 
 
 16-7 grms. 
 
 33-4 grms. 
 
 Uric acid 
 
 0-4 „ 
 
 0-6 •„ 
 
 0-8 „ 
 
 Alkaline phosphates 
 
 0-9 „ 
 
 1-6 „ 
 
 2-1 „ 
 
 Earthy phospliates . 
 
 0-.5 ,. 
 
 0-8 „ 
 
 1-3 „ 
 
 Chlorides 
 
 1-2 „ 
 
 3-4 „ 
 
 6-2 „ 
 
 Sulphates 
 
 0-7 „ 
 
 1-i ., 
 
 2-6 „ 
 
io6 Clinical Chemistry. [Chap. iv, 
 
 In calculating the amount of solids passed in 
 disease, we must allow a range of one-fourth of the 
 mean amount, above and below that amount. The 
 quantity of urine passed in the twenty-four hours is, 
 however, no measure of the amount of solid matter 
 passing out of the body by the kidneys, since 30 
 ounces of urine may contain as much solid matter as 
 60 ounces. The amount of solid matter is therefore 
 determined either by evapoi^ating the urine and 
 weighing the residue, or else by taking the specific 
 gravity of the urine by means of a urinometer, 
 and calculating the solids from the density. The 
 former process is tedious, and requires an expen- 
 diture of time which precludes its employment 
 when examinations have to be made daily. For 
 clinical purposes the solids may be calculated, when 
 precautions are taken to ensure accuracy, from the 
 specific gravity. The calculation is based on the 
 fact that normal human urine of twenty-four hours 
 contains 4 per cent, of solid matter, and that the 
 specific gravity of that urine is registered at about 
 1'020. By multiplying the two last figures of the 
 specific gravity by 2 we get 40 in every 1.000 parts, 
 or exactly 4 per cent. A thousand grains, therefore, 
 of urine, specific gravity 1 "020, contains 40 grains of 
 solid matter ; or, if French measures are employed, 
 1000 cubic centimetres of the same specific gravity 
 contain 40 grammes. As stated in the above table, the 
 quantity of water passed in twenty-four hours is 1450 
 centimetres, or 50 ounces ; then the quantity of 
 solids as calculated from the specific gravity discharged 
 in the same period will amount to 2 ounces, or 54 
 grms. In making calculations based on the specific 
 gravity, it is important to note the temperature at 
 the time the observation is made, since a difier- 
 ence of 7° F. from the temperature at which the 
 urinometer was graduated represents a difierence of 
 
Chap. IV.] Srr.ciFic Gravitv. 107 
 
 one degree. The observation of tlic si)ecific gravity 
 in connection with the amount of urine piissed in 
 the twenty-four hours, aflbrds in itself an important 
 indication as to tlic metamorphoses going on in the 
 body. 
 
 Under the terms liydruria, diabetes, polyuria, etc., 
 authors have described certain morbid conditions of 
 the urine, characterised by excessive and persistent 
 discharge. JNIost authors apply either of the above 
 terms indifferently, without reference to the quantita- 
 tive relationshij) that may exist between the urinary 
 water a,nd solids. The following classification will 
 assist the memory : 
 
 (1) Hijdruria. — A copious discharge of aqueous 
 urine. In these cases there may be a decrease in the 
 solid constituents of the urine, but there is certainly 
 no increase. Extreme instances of liydruria are met 
 within cases of "diabetes insipidus," in which the 
 daily urinary flow may amount to 7,000 to 9,000 
 cubic centimetres of a specific gravity of 1 '002. As a 
 temporary condition it is frequently met with in 
 hysterical females and persons of highly neurotic 
 temperament. Associated with minute traces of 
 albumin, it is a condition of urine met with in 
 granular kidney ; the amount of diuresis, however, 
 is not so extreme, nor is the specific gravity so low, as 
 in typical instances of diabetes insipidus. 
 
 (2) Polyuria. — An increase of water with an in- 
 crease of urinary solids, dependent on increased tissue 
 metabolism. In these cases all the urinary con- 
 stituents seem to be increased. In this division 
 we have those cases of increased elimination of urea 
 to which Prout assigned the term " azoturia " ; and 
 those cases which Dr. Tessier has described as 
 " phosphatic diabetes," where the amount of j^jhos- 
 phoric acid excreted is enormously increased. " Azo- 
 turia " and "phosphatic diabetes" are probably allied 
 
io8 Clinic AT. Chemistry. [Chap. iv. 
 
 conditions, due to increased tissue metabolism taking 
 place under nervous disturbance. Both forms have 
 been met with associated with the following con- 
 ditions : (a) Cases in which nervous symptoms 
 are predominant; (6) accompanying pulmonary con- 
 sumption ; (c) cases which alternate or co-exist 
 with saccharine diabetes ; (rf) which run a distinct 
 course, resembling saccharine diabetes, but withoiit 
 sugar. 
 
 (3) Diabetes mellitus. — Increase of the urinary 
 water, together with constant (unless checked by diet) 
 excretion of glucose in excessive amounts. The 
 occasional appearance of sugar in urine is not to be 
 taken as an indication of true diabetes mellitus, but as 
 diie to temporary functional disturbance of the liver, 
 though it must not be overlooked that temporary 
 "glucosuria" is often precursory of the more serious 
 disease. In cases of diabetes mellitus the relation- 
 ship between the amount of urine excreted and the 
 urinary solids are very various. In typical cases the 
 relationship is pretty constant ; whilst the water 
 is considerably increased there is superabundance of 
 sugar, and the urea, probably owing to increase of 
 nitrogenous diet, is considerably in excess. In a 
 second class of cases we find a considerable increase 
 in the amount of urine, the sugar moderate in quan- 
 tity, the urea not much increased, in some cases 
 even below the normal, and the urine frequently 
 albuminous. In a third group of case^s the urinary 
 water is only moderately increased, the sugar rarely 
 exceeding 2|- per cent., whilst the urea is generally 
 considerably in excess, more than can be accounted 
 for by increase of nitrogen ingested. No satisfactory 
 explanation has been offered to account for these 
 variations, the latter, as the least frequently observed, 
 is probably an early stage of the former ; the marked 
 increase of the urea excreted, as compared to the 
 
Chap. IV.] Reaction of Urine. 109 
 
 iiioilorate amount of sugar generally noticeable, points 
 to increased tissue metabolism. These cases, after a 
 comparatively mild course, often suddenly develop 
 into acute diabetes, and run a ra[)id course, ending in 
 diabetic coma. 
 
 Baruria. — The urinary water is not increased, may 
 even be diminished, but the ui'inary solids are in excess. 
 From the concentrated iirine, urates are frequently 
 deposited. Dr. Fuller was the finst to apply the term 
 baruria ()3api'/s^ heavy) to this class of urines, which he 
 associated with certain forms of dyspepsia (J/ef/.-6'/ttV. 
 Trails., vol. li.). It is a condition of urine found in 
 a class of cases described by Murchison as due to 
 IWictimia. 
 
 Anazotarin. — This term was originally applied by 
 Willis to a class of cases in which there was a copious 
 discharge of pallid urine, with marked deficiency of 
 urea. These cases, however, should be referred, T 
 think, to the class hydruria. The term anazoturia is 
 better applied to the cases described by Dr. Andrew 
 C'larke as due to " renal inadecpiacy." In these there 
 is no marked increase in the amount of urine passed, 
 but a notable deficiency in the amount of urea 
 excreted. As it is still uncertain whether this con- 
 dition dei)ends on inadequacy of the renal functions, 
 or on deficient metamorphosis of tissue generally ; a 
 term Avhich defines the actual condition of the urine, 
 rather than one which commits us to an hypothesis, is 
 for the present decidedly the safest. 
 
 107. Reaction. — Within a period of twenty- 
 four hours the reaction of healthy urine will be found 
 to vary considerably. Thus before meals it will have 
 a high range of acidity, whilst after food it will become 
 nearly neutral, or even sometimes alkaline. This 
 depi'e.ssion of acidity, which has been called the alka- 
 line tide, has been accounted for by Dr. Bence Jones, 
 by the fact that at the moment of its occurrence, 
 
no Clinical Chemistry. [Chap. iv. 
 
 acid is being drawn from the circulation to supplj'- 
 the gastric juice. Dr. Roberts, of Manchester, how- 
 ever, regards the depression as due to the intro- 
 duction of newly-digested food into the blood, which 
 supplies it with alkaline bases. Although both ex- 
 planations are based upon actual observation, yet as 
 the acidity of the urine can be depressed, and even 
 rendered alkaline, by other circumstances besides those 
 attendant on digestion, as the mere act of rising in the 
 morning before breakfast is taken, or the cold douche, 
 or sweating in the vapour bath, some other explanation 
 must be offered to explain the depression in these 
 cases. And this, I think,* is to be found in the fact 
 that there is another channel by which acid is with- 
 drawn from the blood beside the gastric secretion, and 
 that is by the lungs. In the explanations hitherto 
 advanced to account for the phenomenon of the 
 alkaline tide in the urine, this fact has not received 
 attention. Dr. Edward Smith, in his researches "On 
 the Elimination of Carbonic Acid," has shown con- 
 clusively that the exhalation of carbonic acid by the 
 lungs is increased by food and diminished by fasting, 
 and that the amount exhaled during sleep is consider- 
 ably less than is set free in the waking state. It 
 therefore happens that the time when most carbonic 
 acid is being exhaled corresponds with the time when 
 observers have noticed a decided diminution in the 
 acidity of the urine, whilst the circumstances that 
 diminish the exhalation of carbonic acid (namely^ 
 sleep and fasting), are attended by a rise in the acidity 
 of the urinary secretion. 
 
 The acid reaction of the urine is chiefly, if not 
 entirely, due to the presence of acid sodium phos- 
 phate, and occasionally to an excess of acid salts of 
 hippuric and uric acids. It is only recently that an 
 
 * " Morbid Conditions of Urine dependent on Derangements of 
 Digestion." Chiu-chill, 1882. 
 
Chap, iv.i Reaction of Urine. hi 
 
 explanation has been offered to account for the 
 seeming paradox of the separation of an acid secretion 
 like urine from alkaline blood. In 1874 I pointed 
 out* that it might V)c tlie result of the decomposition 
 between the neutial sodium phosphate and acid sodium 
 carbonate (bicarbonate), both of which exist in the 
 blood, resulting in the formation of acid sodium 
 phosphate, and noi-mal sodium carbonate. The former 
 diffuses out through the renal parenchyma, whilst the 
 latter remains in the blood (§ 93). Maly, how- 
 ever, believes that acid sodium ])hosphate exists in a 
 free state in the blood, ami ho has shown that if a 
 mixture of neutral sodium phosphate and acid sodium 
 ]iliosphate be placed together in a dialyser, the acid 
 salt passes into the sui-rouuding distilled water. 
 Maly's explanation has the merit of simplicity, but 
 it does not wholly account for many of the phenomena 
 connected with the variations in the reaction of the 
 urine. If, on the other hand, the view that the acidity 
 of the urine is caused by the reaction between acid 
 sodium carbonate and neutral sodium phosphate be 
 accepted, it will explain another pai'adox which has 
 been observed by Bence Jones, Beneke, Parkes, and 
 myself, to occur after the administration of the 
 bicarbonates (acid carbonates) of ammonia, potash, and 
 soda, under certain conditions, viz. causing of an in- 
 creased acidity of the urine. The free acidity of the 
 urine is reckoned as oxalic acid, and in the healthy 
 state the total acidity of the twenty-four hours' urine 
 is equal to a degree of acidity rei)resented by fi'om 1 -5 
 gi-ms. to 2 grms. of oxalic acid. 
 
 After it has been passed, the urine, if originally 
 acid, increases its degree of acidity owing to the 
 acid fermentation of the pigment and extractive 
 matters ; the highest degree of this acid fermentation 
 is reached about the third day. The urine then 
 * Lancet, July 21, 1874. 
 
112 Clinical Chemistry. [Chap. iv. 
 
 gradually becomes alkaline from the ureal decompo- 
 sition. 
 
 In disease the acidity of the urine may become 
 persistently highly acid or persistently alkaline (fixed 
 or volatile), or there may be fluctuations, a high degree 
 of acidity alternating with a neutral or alkaline con- 
 dition. The variations in the reaction of the urine 
 in disease will therefore be considered under three 
 heads. 
 
 (1) Highly acid urine. — Urine may become more 
 acid, relatively, owing to concentration of the urine. 
 Thus, in hot weather, owing to the increased action of 
 the skin, the amount of urinary water is lessened and 
 the urine becomes denser. Similarly in pyrexia, 
 especially if attended with profuse sweating, as in 
 rheumatic fever and in diarrhoea. In diabetes mellitus 
 the acidity of the urine is considerably increased ; 
 when freshly passed it has a degree of acidity con- 
 siderably above the average, and becomes more acid 
 after being kept some hours, owing to lactic and acetic 
 acid fermentation which takes place. In acid dyspepsia, 
 so called on account of its supposed association with 
 hypersecretion of acid gastric juice, the urine is at 
 times highly acid, alternately, however, with urine 
 that is neutral or even alkaline. This variability in 
 the reaction of the urine is frequently to be met with 
 in children, in whom irregular secretion of the gastric 
 juice is very readily excited. The degree of acidity 
 is determined by neutralising 100 cc. of urine with 
 a solution of sodium hydrate, standardised so that 
 1 cc. = "01 grm. of oxalic acid. The number of cc.'s of 
 the standard solution employed to effect neutralisation, 
 multiplied by -Ol gives the degree of acidity in 100 cc. 
 of urine, and from this the total acidity of the twenty- 
 four hours' urine can be calculated. 
 
 (2) Urine alkaline from fixed alkali — This con- 
 dition is due either to excess of the alkaline carbonates 
 
Chap. IV.] Reaction of Urine. 1 1 3 
 
 of soda and potash, or the alkaline j)hosphates; often to 
 an excess of both, (a) Excess of alkaline carbonates : 
 The urine eflervesces on the adilition of strong acids ; 
 it is generally turbid from precipitation of the earthy 
 phosphates, though these are not necessarily excreted 
 in excess. Indeed, in many cases I have found them 
 diminished ; on the other hand, the urine may contain 
 an excess of uric acid. This condition of urine may 
 arise, (1) from genernl debility and the feebleness witli 
 which the respiriitory act is performed, leading to the 
 accumulation of carbonic acid in the system. With 
 regard to this point, it is interesting to note that 
 urine alkaline, from the presence of carbonates of 
 the fixed alkalies, is frequently met with in patients 
 convalescing from acute diseases. (2) Diminished 
 secretion of bile, which is the frecjuent result of the 
 duodenal catarrh produced by the irritation of the acid 
 contents of the stomach being poui-ed intothe intestines, 
 gives rise to an accumulation of alkaline carbonates in 
 the blood, the l)ile being the chief secretion by whicli 
 alkaline salts are removed from the body ; for though 
 a portion of them are undoubtedly reabsorbed into the 
 blood from the intestines, a considerable proportion 
 of them are discharged with the faeces. Obstruction, 
 therefore, to the discharge of bile leads to their retention 
 in the blood, and consequently being eliminated in 
 greater quantity by the kidney. (3) The acids formed 
 by fermentative changes being of the fatty acid series, 
 these, on entering the sj^stem, are oxydised into carbonic 
 acid, and this uniting with the bases of the alkaline 
 oxides, forms carbonates of these bodies, and by increas- 
 ing the alkalescence of the blood will diminish the 
 natural acidity of the urine and even render it alkaline. 
 The dyspepsia generally associated with this foi'm of 
 alkaline urine is attended with great depression of 
 spirits, the bowels are constipated, flatulence is a pro- 
 minent symptom, the skin is sallow and dry, and the 
 I 
 
114 Clinical Chemistry. [Chap. iv. 
 
 fiinctions of tlie liver evidently deranged. The urine, 
 after remaining alkaline for some days, depositing 
 oxalates and phosphates, often becomes suddenly acid, 
 and deposits large quantities of uric acid. 
 
 (6) Excess of alkaline phosphates of soda and 
 potash : Little is known regarding the pathological 
 significance of ui'ine alkaline from this cause. It is, 
 however, frequently met with in neurotic individuals. 
 In the majority of cases the earthy phosphates are in- 
 creased as well as the alkaline carbonates. Excessive 
 elimination of the alkaline phosphates has been noticed 
 in cases of acute inflammation of the membranes of 
 the brain, in the acute paroxysms of certain forms of 
 mania, after injuries to the head, and in certain obscure 
 spinal afiections, probably functional in character. 
 The urine, in these cases, is generally increased in 
 quantity ; on passing from the bladder the first portion 
 may be clear and the remainder thick. Sometimes a 
 small quantity, consisting almost entirely of amorphous 
 phosphate of lime, may be passed with considerable 
 straining and feeling of irritation immediately after 
 the flow. Urine alkaline, from either excess of alkaline 
 carbonates or phosphates, must not be confounded with 
 true phosphaturia when there is an excessive excretion 
 of earthy phosphates. In simply alkaline urines there 
 may be a deposit of earthy phosphates, though there 
 need not necessarily be an excess. In phosphaturia, 
 even with considerable excess of calcium phosphate, 
 there is no deposit, and the urine is often acid 
 (§ 113). The degree of alkalescence is determined 
 by neutralising 100 cc. of the urine by a solution 
 of oxalic acid, standardised so that 1 cc. = "01 grm. 
 of sodium hydrate ; the number of cc.'s of the 
 standard solution employed to effect neutralisation 
 multiplied by "01 gives the degree of alkalescence in 
 100 parts ; and from this the total alkalinity of the 
 twenty-four hours' urine can be calculated. 
 
Chap. IV.) AmMONIACAL UlilNE. II5 
 
 (3) Urine alkaline from volatile alkali (amnioniiim 
 carbonate). — Tliis condition is induced by disease 
 of the genito-iirinary organs, since experiments on 
 Jiealtl)y anijnals sliow that tlie nrine does not become 
 amnioniacal by prolonged retention in the l)ladder, so 
 long as that oi'gan does not become inflamed, and also 
 that the introduction of the " ammoniacal ferment" 
 into the bladder of animals will not cause decomposi- 
 tion of urea so long as the mucous membrane remains 
 healthy. Feltz and Ritter, fi-om observations made 
 on seventy-eight persons suffering from different 
 diseases, came to the conclusion that the urine does 
 not become ammoniacal unless received into dirty 
 ^■essels, or mixed with products of the decomposition 
 from the mucous surfaces of the genito-urinary appa- 
 ratus. In one of their cases a patient was taking 0-2 
 gramme of bichloride of mercury daily, and the urine 
 was analysed every day ; the acidity fell on the ninth 
 day to -02 gramme, on the tenth day it was neutral, 
 on the eleventh day it was alkaline and ammoniacal. 
 This change in the I'eaction coincided with the appear- 
 ance of a trace of albumin in the urine, which was 
 turbid, and contained flakes of epithelium and leuco- 
 cytes. In some cases of scarlet fever I have noticed 
 that when albumin appeared in the urine the reaction 
 frequently became alkaline, and crystals of ammonio- 
 magne.sium phosphates were deposited. Dr. Owen 
 Rces has advanced a theory that it is by no means 
 necessary for ammoniacal urine to depend on decom- 
 position of the urea ; he maintains it can be formed by 
 the secretion of the mucous membrane, which owes 
 its alkalinity to fixed alkali, and which, mixed or 
 mingled with the urine, unites with the acids of the 
 ammoniacal salts and thus liberates the ammonia. In 
 answer to this view it is sufficient to state that the 
 existence of ammoniacal salts in tlie urine, except as 
 the result of the decomposition of ui-ea, has been 
 
ii6 Clinical Chemistry. [Chap. iv. 
 
 denied by most chemists, and that if Dr. Owen Rees' 
 view were correct, ammoniacal urine would be more 
 frequent than it is, since whenever the mucous 
 secretion of the urinary passages was increased the 
 urine would become ammoniacal. Clinical expe- 
 rience teaches us that this is not the case. At the 
 same time, there can be no doubt that the presence 
 of fixed alkali in urine greatly favovirs ureal decom- 
 position, and the process is induced more rapidly. 
 Whenever the urine becomes ammoniacal, crystals 
 of ammonio-magnesium phosphates are formed, which 
 either pass away as gravel or are retained as a calcu- 
 lous deposit. We distinguish between the reaction 
 due to fixed alkali and that of volatile alkali by the 
 fact that with the former the blue colour given to 
 red litmus does not disappear on drying, whilst with 
 the alkalescence due to ammonia the blue tint is 
 evanescent. 
 
 108. Colour. — The nature of the pigment that 
 imparts the colour to the urine has been the subject of 
 much discussion. Spectroscopic analysis has recently 
 thrown fresh light on the subject, MacMunn has 
 shown that human urine always gives an absorption 
 band at F in the same manner as choletelin^ the pig- 
 ment obtained by Jaffe from bile. He thinks all 
 the colouring matters of the bile are produced from 
 hsematin by reduction, due to the action of the bile 
 acids on hsemoglobin. All the colouring matter of 
 the bile, including hsematin, urobilin of biliary origin, 
 bilirubin, etc., are oxydised to clwletelin, and there is 
 evidence to show that blood serum contains this body 
 on its way to be excreted by the kidneys. The uro- 
 bilin of the bile is produced in the intestine, and may, 
 in certain conditions of the system, appear as such in 
 the ux-ine, but under normal conditions is oxydised into 
 clwletelin, which must be considered one of the chief 
 urinary pigments. Most of the urinary pigments may 
 
Chap. I V.J l/KINA/n- P/GMKNTS. W] 
 
 thus be traced back to urobilin of l)ili:uy ori^jjin ; but 
 there is also evidence to show tliat some of them are 
 derived from hivniatin directly, and that pigments 
 derived from that source may occasionally entirely 
 i'i'j)lace the normal jiigment. The .sjjectroscopic char- 
 acters of the ]>ignient dillei'. In febrile urine the black 
 band in v is sharp, in normal ui'ine it is less marked 
 at tho edges and less shaded. The band is well seen 
 in alcoholic solutions, and is destroyed by the action 
 of caustic alkalies. In addition to the pigment above 
 described as related to urobilin and convertible into 
 it, most urines contain a pigment allied to, if not 
 identical with, indican, and which is commonly known 
 as uroxanthin. The source of this body is probably 
 from indol formed by the decomposition of j^roteid 
 substances by pancreatic digestion, since indican is 
 found in the urine of animals after the subcutaneous 
 injection of indol, and also after ligature of the small 
 intestines (§ 7G). In many diseases the amount 
 that appears in tlie urine is considerably increased, 
 as in diabetes, dysentery, the reaction stage of 
 cholera, in ob.struction, and other aiFections of the 
 intestines. Urines containing this substance, when 
 heated with strong acids, give rise to blue. gi*eenish, 
 and red pigments (the blue and green urines some- 
 times met with in disease may thus be referred to 
 indican in different states of oxydation) ; these some- 
 times occur spontaneously in urine. Urines con- 
 taining much indican are invariably highly acid (and 
 this acidity inci'eases on keeping), and they generally 
 deposit a considerable amount of uric acid, and 
 partially decompose a solution of sulphate of copjjer. 
 Whether this reduction is due to the presence of uric 
 acid in excess, or to the fact that indican is a glu- 
 coside, and yields on decomposition a molecule of 
 glucose, is not determined. Jllelaniti, a black pigment, 
 occurs pathologically in the urine in patients sutiering 
 
ii8 Clinical Chemistry. [Chap. iv. 
 
 from melanotic tumours ; it is sometimes found in the 
 urine of persons suffering from ague. It is soluble in 
 caustic potash, and can then be decolorised by passing 
 chlorine through the solution. The colour of the 
 twenty-four hours' urine is light amber, the urina 
 sanguinis and urina cibi a golden amber, the urina 
 potu a pale straw colour. It must not be forgotten 
 that many articles of diet and medicine impart a 
 colour to the urine. The presence of blood, bile, 
 albumin, sugar, change the colour of the urine. 
 These alterations will be considered under their 
 respective heads. 
 
 109. Odour. — Normal urine has an odour sui 
 generis. It is described as aromatic. Alkaline urine 
 evolves an ammoniacal odour when its alkalinity is 
 due to volatile alkali ; a faint mawkish smell, like that 
 of horses' urine, when alkaline from fixed alkali. 
 Diabetic urine is said to exhale a whey-like fragrance. 
 Urine containing cystin at first smells like sweet- 
 briar, but speedily becomes horribly offensive. In 
 certain forms of dyspepsia the urine has a sickly 
 })enetrating odour. Medicines and certain articles of 
 food often impart a peculiar odour to urine, as tur- 
 pentine, the fragrance of violets, and asparagus, a 
 peculiarly rank foxy odour. 
 
 110. Urea CH4N2O. — About one ounce of this 
 body, or, if we calculate in French measures, about 
 33 grammes of this substance, are passed out of 
 the body in the urine in the course of twenty-four 
 hours. We have already stated (§ 79) that urea is 
 isomeric with ammonium cyanate. With regard to this, 
 attention has been called to the fact that urea is a much 
 more stable body than ammonium cyanate, and that 
 in the transformation of the latter into the former, 
 energy is set free. Thus, ammonium cyanate is the 
 type of living, and urea of effete, nitrogen, and the 
 conversion of the former into the latter is the image 
 
Chap. IV.] Urea. 119 
 
 of the essential cliangt; which takes place when a living 
 prot(U(l dit's. It is prul)al)h!, iiion^ovcr, that cyanoi^eu 
 c<)iii[)ouii(ls precede Ww. forniatioii of urea, and act 
 with great niok!cidar eii(M-gy till they j)ass into the 
 mure stabh^ but ell'ete form of urcsa, when they are 
 cast out of tli(! body. Urea thus represcaits the ulti- 
 mate product of the nietal)olism of the nitrogenous 
 constituents of the food and tissues. In health, the 
 amount excreted is ])roportionate to this nietaijolisni ; 
 in disease, however, no such relationshii) is maintained. 
 The amount is increased in all acute diseases, and is 
 especially marked during pyrexia! exacerbations. In 
 typhus fever the excretion is highest during the first 
 ^\■eek, the excretion then bcdng often double that of 
 the fourth week, although the patient during the first 
 stage is on low diet, and during the latter period on 
 meat diet. In relapsing fever the iirea is inci'eased 
 during the paroxysms, and diminished during the in- 
 terval. In enteric fever, urea is excreted in the largest 
 amounts dui'ing the first week of the disease, it then 
 gradually diminishes. Still the quantity continues in 
 excess of the normal standard as long as the fever 
 lasts ; the amount excreted daily during the disease is 
 not influenced by the amount of diarrhoea. In erup- 
 tive fevers as measles, small-pox, and scarlet fever, 
 urea is increased in amount during the first four days. 
 If, in the latter disease, kidney com})lication sets in, 
 a sudden fall takes place. In intermittent fevers, 
 the urea of the twenty-four hours is not markedly 
 increased, but during a paroxysm, and just before it, 
 there is a decided increase, followed by a decrease. 
 The reason of the increase of urea accompanying or 
 l)receding a rise of temperature, has been given (§ 7). 
 As the liver is the organ in which metabolic changes 
 leading to the formation of urea are the most active, 
 though it has now been shown most conclusively that 
 urea is also produced largely from the leucin, the result 
 
I20 Clinical Chemistry. rchap. iv. 
 
 of pancreatic digestion, and from tlie kreatin in muscles, 
 disease or disturbance of functions of that organ 
 especially affect the excretion. In acute yellow atrophy 
 the urea is slightly increased at first, during the hyper- 
 semic stage, but rapidly decreases as the disease ad- 
 vances, and when the liver cells are destroyed, nearly 
 all trace may disappear from the urine, its place being 
 taken by uric acid, leucin, and tyrosin, and some ill- 
 defined albuminoid bodies resembling peptones. In 
 hepatic abscess and in cancer of liver a notable diminu- 
 tion is observable. In diseases of the kidney, in both 
 acute and chronic forms of nephritis, the excretion 
 of urea is lessened ; although no relationship exists 
 between the discharge of albumin and excretion of urea, 
 still a more favoui-able prognosis may be expressed 
 when the urea does not progressively diminish. In 
 the albuminuria of pregnant women the amount 
 of urea in the urine is only slightly diminished. 
 In a case of Dr. Maxwell's, of Woolwich, I found 
 urea in the twenty four hours' urine to the amount 
 of 27 grammes, a little below the normal. In a 
 case of Dr. John Williams', in the urine of twelve 
 hours immediately preceding venesection the urea 
 was 14-26 grammes, and the albumin was 4'9 
 grammes ; in the twelve hours' urine immediately 
 succeeding venesection, I found urea 15-6 grammes, and 
 the albumin 2 "6 grammes. Bleeding, therefore, had 
 little effect on the excretion of the urea, which in both 
 periods was only little below the normal, but it mate- 
 rially reduced the amount of albumin. In diabetes, 
 urea is always largely in excess, in measure due no 
 doubt to the increased quantity of animal food con- 
 sumed ; still this does not altogether explain the whole 
 of the increase. A sudden fall in the excretion is an 
 unfavourable sign, as it often is a prelude to diabetic 
 coma, in which state both urea and sugar are excreted 
 in lessened quantities ; the fall in the urea usually 
 
M 
 
 Chaj.. IV.] Ul<r.A. 121 
 
 precedes that of the su<;ai-. In iitcrine disciiscs a 
 temporary excess of urea in the urine is to be met 
 with. It is said to be increased botli before and after, 
 but diminished during, tlie menstrual period. In the 
 ]H'riodic jaundice recurring at tlie menstrual periods 
 (icterus vieiislrnaJis) urea is increased. In ])hthisis 
 the exci'etion of urea corresponds with the 
 pyrexia. Ila])id]y growing cancer causes a 
 diminution, a fall from 29 •5 grammes to as 
 low as 6-9 has been recorded. In certain 
 constitutional states urea is also diminished, 
 P u re '"^^ ^^^ patients suflering from anaemia, liydriemia. 
 Urea, clironic alcoholism, and syphilitic cachexia. 
 Under the term " renal inadequacy," Dr. 
 Andrew Clarke has described condition in which only 
 a very small quantity of urea is continuously passed, 
 although there is no recognisable disease present. 
 These cases improve on a carefully regu- 
 lated dietary. As a converse to these are 
 cases which habitually excrete an enormous 
 amount of urea, together with the other 
 urinary constituents. Dr. Prout termed 
 this condition azoturia, though it may 
 more aj^propriately be termed polyuria ; it 
 often precludes phthisis, or may be an 
 antecedent condition of diabetes mellites. (For 
 (jualitative tests for urea, see § 7.) For clinical 
 jiurposes urea is often roughly estimated by the 
 ])recipitation of nitrate of urea, by adding an equal 
 volume of strong nitric acid to the urine ; if nitrate 
 of urea is thrown down without concentration of the 
 urine, then it is said to be in excess, if concentrated 
 to half its bulk, about normal ; if further concen- 
 tration is required, then less than normal. It is needless 
 to point out the fallacy of this method, since unless 
 the quantity of urine passed and the specific gravity 
 are likewise noted, urines containing absolutely a 
 
122 Clinical Chemistry. [Chap. iv. 
 
 considerable quantity of urea may be passed by the 
 })atient in a very dilute form, whilst others, containing 
 only an ordinary quantity, may be voided in a concen- 
 trated state, and give the reaction, and thus mislead 
 the physician. For accurate determination, recourse 
 must be had to volumetric analysis : (a) Liebvjs inetliod. 
 I'or this purpose 40 cc. of urine are taken, and freed 
 from albumin if present by heat and filtration, and 
 mixed with exactly the same quantity of a solution of 
 barium hydrate (2 volumes) with barium nitrate (1 
 volume); this precipitates the phosphates and sulphates; 
 a few drops of solution of nitrate of silver are then 
 added, which precipitates the chlorides. Set aside till 
 the precipitate has collected at the bottom of the 
 beaker, then filter, and of the clear filtered solution 
 take 20 cc, reserving the remainder in case of acci- 
 dent. This of course represents 10 cc. of urine. Now 
 run into this solution, from a burette, 10 cc. of stan- 
 dardised solution of mercuric nitrate, stir the mixture 
 well, withdraw a drop on a glass rod, and let it fall on 
 a drop of sodium carbonate solution placed on a white 
 plate or on a flat porcelain dish. If a yellow stain 
 occurs the process must be repeated with the reserve 
 stock ; but this is ^^nlikely, unless the urea is very 
 inconsiderable indeed. If there is no stain, add 5 cc. 
 more, and then test again ; if no reaction occurs, repeat 
 the process more cautiously, adding 1 cc. at a time till 
 a yellow stain, due to the formation of hydrated oxide 
 of mercury, is at last produced. Now as each 1 cc. 
 of the standard solution of mercuric nitrate is equi- 
 valent to -01 gramme of urea, the number of cc.'s 
 employed to produce the yellow stain indicates the 
 number of grms. present in 10 cc. of urine, from 
 which the amount in the twenty-four hours' urine can 
 readily be deduced. (5) Russell and West's method 
 is based on the fact that hypobromous acid decomposes 
 urea into water, carbonic acid, or nitrogen. The 
 
Chap. IV.] Uric Acid. 123 
 
 latter gas is collected alone in a graduated tul)0, wliicli 
 is standardised so that eacli measure represents ojio 
 gramme of urea in 100 cc. of urine. In employing 
 this test for tlie detcriiiination of urea in diabetic 
 urines, it must be remenib(!red that grai)e sugar in- 
 creases tlie quantity of nitrogen evolved from urea by 
 sodium liypobromite by (juite seven per cent. The 
 deficiency of nitrogen yielded with pure solution of 
 urea, under the hyperbromite test, is about eight jjer 
 cent., the addition of glucose, therefore, brings it uj) 
 to the theoretic yield. This is of little importance 
 unless the analyses are made for purpose of comparison 
 of diabetic with non-saccharine urine. In making a 
 series of observations, care must be taken always to 
 secure the same temperature, as a slight decrease or 
 increase makes a considerable diflerence in the gas 
 volume. From non-attention to this important par- 
 ticular, many discordant results have been obtained. 
 After considerable experience I have come to the con- 
 clusion that Liebig's method is not only the most 
 reliable, but after a little experience quite as readily 
 p(!rformed as the other. 
 
 111. Uric acid C^HiNjOs. — "Was discovered by 
 Scheele in 1776, and was at first thought to be solely 
 a constituent of urinary calculi, hence the term 
 lithic acid usually ap[)lied to it. In 1797, Woollaston 
 showed that gouty tophi were composed of sodium 
 urate; whilst, in 1848, Dr. Garrod brought forward 
 the fact that in true gout an excess of uric acid exists 
 in the blood prior to and at the period of the attack. 
 
 From the circumstance that uric acid is a di-ureide, 
 that is, by oxydation a molecule of uric acid can be 
 split up into a molecule of a non-nitrogenous acid and 
 two molecules of urea, it has been assumed that when 
 the process of oxydation is imperfectly performed 
 within the body uric acid will be found in excess in 
 the blood ; and this assumption has been further 
 
124 Clinical Chemistry. [Chap. iv. 
 
 strengthened by tlie supposition that uric acid is one 
 of the substances through which each particle of 
 albumin passes before it is thrown out of the body. 
 This view has for many years completely dominated 
 urinary pathology. Now, however, since it has been 
 shown that uric acid is not a necessary antecedent 
 of urea, which is largely formed from kreatin in 
 muscle, and leucin and other bodies in the alimentary 
 canal, the view has gained ground that uric acid in 
 the human body in health is only formed in minute 
 quantities, and that even in disease it is not formed in 
 anything like the amount formerly supposed, and that 
 when it is deposited from the urine or in the tissues, 
 the fact of the occurrence of such deposit may be 
 generally referred to its insolubility rather than 
 excessive production in the system. It is now taught 
 that while uric acid is met with in small quantities in 
 the large glands like the spleen, liver, etc., in health 
 it is never found in the blood ; so that uric acid is 
 probably oxydised as soon as formed, and that the 
 small quantity found in normal urine, only 0*5 
 gramme, or about 7 grains, a whole day's excretion, 
 is not derived from the blood, but from the kidney, 
 which, instead of being oxydised, as is the case with 
 other organs, passes away with the secreted urine. In 
 many diseases attended with considerable tissue 
 metamorphosis, the amount of uric acid formed in the 
 large organs is increased, and a portion not completely 
 oxydised passes into the blood, and froin thence into 
 the urine, though even then the amount is never 
 large, rarely exceeding 1 -5 grammes in the twenty -four 
 hours as an outside avera,ge ; in these cases there is, as 
 well, generally an increase ii;i the amount of urea ex- 
 creted. In gout there may be an increased production, 
 but most likely, as Dr. Garrod suggests, it is due rather 
 to an accumulation in the blood, caused by a resorption 
 in the uric acid formed in the kidney not being excreted 
 
Chip. IV.] Uric Acid. 125 
 
 Avith the urino, but takoii up by the blood and carried 
 the round of the circuhition in combination with soda, 
 and deposited in tlie least vascular parts, the cartilages 
 of the joints, the cartilages of the ear, the straight 
 tubules of the kidney, etc., as sodium urate. Uric 
 acid is the most insoluWc of all the substances formed 
 in the body, requiring 15,000 parts of water for 
 solution, whilst urea is soluble in its own weight. It 
 is, therefore, fortunate that those animals whose 
 urinary a})paratus is not adapted for cari'ying off solid 
 or semi-solid urine like birds and reptiles, that soluble 
 urea replaces the insoluble uric acid, otherwise 
 calculous disease would be infinitely more common 
 than it is. Owing to this insolubility, whenever the 
 amount of water in the urine required to keep uric acid 
 and its salts in solution falls below a certain point, 
 then uric acid or its salts are deposited. In acid con- 
 ditions of the urine, uric acid and its salts, unless 
 heated, are almost altogether insoluble, so that when 
 the natural acidity of the urine is at all heightened, 
 they are at once deposited. The following summary 
 gives the chief conditions which lead to a deposit of 
 uric acid in the urine, or its excessive elimination 
 from the body. 
 
 (a) Deposits of uric acid or urates, not, however, 
 necessai'ily eliminated in excessive quantities. 
 
 (i) Absolute increase in the acidity of the urine. — 
 The occasional deposit of urates observed in winter 
 arises from this cause. The action of the skin being 
 checked, the acidity of the urine increases during cold 
 weather. Similarly in many extensive cutaneous 
 diseases,, such as eczema and psoriasis, uric acid 
 deposits are of frequent occurrence ; also in forms of 
 dyspepsia associated with irregular secretion of gastric 
 juice. 
 
 (2) Relative increase in the acidity of the vriiie. — 
 The deposits of urates frequently noticed during the 
 
126 
 
 Clinical Chemistry. 
 
 [Chap. IV. 
 
 rorms of Uric Acid. 
 
 summer months originate in tiiis way ; tlie cutaneous 
 transpiration being increased in hot weather, the urine 
 is more concentrated. Similai-ly in pyrexia, especially 
 rheumatic fever, and in diar- 
 rhoea. Uric acid deposits 
 alternating with sugar are 
 often caused in this way : 
 since as the sugar disappears 
 urination is not so profuse, 
 and a relative increase in 
 the acidity of the urine oc- 
 curs. This relative increase 
 may not only be caused by a 
 diminution of the water ex- 
 creted, but from deficiency of the alkaline phosphates ; 
 this condition is frequently met with in the urines of 
 ill-nourished or strumous children. 
 
 (b) Uric acid eliminated in excess, but not neces- 
 sarily deposited from the urine. 
 
 (1) tlric acid in excess usually attended with a 
 diminution of the other icrinary constituents {true 
 lithoimia.) — Chiefly in diseases of the liver, such as 
 acute yellow atrophy, cirrhosis, and cancer. In 
 diseases of the spleen, leucocythsemia. In scurvy an 
 excess of uric acid is generally observed, with a dimi- 
 nution of urea and the alkaline phosphates. 
 
 (2) Uric acid in excess attended with an increase 
 of the other urinary constituents. — In functional 
 derangements of the liver, especially those brought 
 about by disturbance of the "nitrogenous equilibrium" 
 by the ingestion of too much animal- food. As a 
 condition antecedent to the development of phthisis 
 or cancer, and sometimes of diabetes, or preceding the 
 outbreak of such constitutional conditions as syphilis, 
 scrofula, and of gout in its early attacks. 
 
 Uric acid when deposited from the ui'ine in a free 
 state resembles grains of cayenne pepper, and presents 
 
Chap. I v.) UkIC AcfD. 127 
 
 iinilcr (Iio iiiicrnscope tlin appoaranco sliowii in 
 Fig. 6. The l)ases met with in urine in combi- 
 nation with uric acid are chiefly those of soda 
 and ammonia, though lime is sometimes present. 
 They are thi'own down as a granular deposit, but 
 amidst the small granules are semi-crystalline bodi(!S 
 depicted (Fig. 7). Both uric acid and its salts 
 are freely sohible in alkaline solutions; this is an 
 important point to remember, not only 
 as regards treatment, but as regards i]), ^ 
 
 their detection in the urine, since their --^st:^ 
 ciystals are frequently modified in fc w, .*^ 
 shajie, may be mistaken for other -X^i^ "^ 
 urinary deposits ; the fact of their 
 dissolving in litpior potasste at once ^*|j ^'u7ate'™of 
 identifies them. Uric acid and ui'ates Sodium (a); 
 yield a magnificent purple when heated mouia (6). 
 with nitric acid, and the dry residue 
 is touched with aunnonia (§ 64). When a con- 
 centrated solution of urates is treated with sti-ong 
 nitric acid, the uric acid is liberated in an amorphous 
 form, in which it is more soluble than in its crystalline 
 state ; on standing it slowly recombines with the 
 sodium salts in the urine, and is deposited as urate of 
 sodium. The peculiar bulky gelatinous preci})itate, 
 soluble when heated, some concentrated urines give 
 when tested with nitric acid for albumin, is due to the 
 uric acid being liberated in this amorphous form. 
 
 Uric acid is determined quantitatively by precipi- 
 tating the in-ic acid from the urine, and by collecting 
 and weighing the cr3'stals. For this purpose place 1 00 
 cubic centimetres of filtered urine (having previously 
 dissolved any deposited urates by heating) in a glass 
 vessel, and add 10 cubic centimetres of strong hydro- 
 chloric acid ; set aside in a cool dark ])lace foi' twenty- 
 four hours. Then carefully collect crystals, and transfer 
 them to a watch-glass, wash thoroughly with dilute 
 
128 Clinical Chemistry. ichap. iv. 
 
 hydrochloric acid, and then transfer them to a 
 weighed filter. Dry in hot-air bath and weigh. The 
 increase in weight over that of the filter will give 
 the amount of uric acid in 100 cubic centimetres of 
 urine. 
 
 If the urine is of low specific gravity, below 1-015, 
 it should be concentrated to one-third its bulk, if 
 below 1-010 to one-half. 
 
 112. Oxalate of lime CaC204. — An extremely 
 small quantity of oxalic acid is met with in all 
 urines, chiefly in combiiiation with ammonia and soda, 
 forming soluble salts. In several morbid states of the 
 system, however, oxalic acid appears in the urine as 
 oxalate of lime, in which case it either comes away as 
 a fine crystalline deposit, or else is retained in the 
 urinary passages to lay the foundation of a calculus 
 (mulberry calculus). Few subjects in uiinary patho- 
 logy have excited keener controversy than that 
 relating to the causes tending to produce deposits of 
 oxalate of lime crystals in urine. The view has been 
 generally held that oxalate of lime in urine was 
 simply derived from the decomposition of uric acid 
 after it had been passed, and that the presence of 
 oxalate of lime in the urine meant nothing more than 
 increased excretion of uric acid. This view was based 
 on. the assumption that oxalic acid represented the 
 imperfect oxydation of uric acid. It will be seen, 
 however, from the following table, that so far from 
 oxalic acid being a product of imperfect oxydation of 
 uric acid, it is only obtainable by oxydation being 
 carried to its ultimate stage : thus 
 
 Uric acid. Alloxan. Urea. 
 
 C5H4NA -h H,0 + = C,H,NA + CH.N^O 
 and 
 
 Alloxan. Mesoxalic acid. Urea. 
 
 C.H^NA + 2H2O = CaH^Os + CH,N,0; 
 
Ch.ip. IV.) Calcium Oxalate. 129 
 
 and mesoxalic acid by further oxydation yields carbonic 
 acid and oxalic acid. It is, therefore, manifestly in- 
 correct to speak, as most writers on urinary pathology 
 have done, of oxalic acid as the imperfectly oxydised 
 product of uric acid ; on the contrary, oxalic acid is 
 only obtained from uric acid by oxydation being carried 
 to its ultimate stage. Now within the body, under the 
 influence of increased oxydation, this reduction of uric 
 acid may occur ; but as a considerable quantity of 
 oxygen is required to etfect the reduction, and as the 
 clinical and pathological conditions in which we meet 
 with oxalate of lime in the urine, do not point to 
 increased oxydation going on within the body, but the 
 reverse, it is manifest that only a small proportion of 
 the oxalic acid can be derived from this source. Again, 
 we stated, when speaking of uric acid, that recent 
 views point to the conclusion that even in disease the 
 amount of uric acid formed in the body is not great, 
 so that no one who has observed the enormous amounts 
 of oxalic acid often passed into urine in a single day, 
 or as it exists in calculi, can believe that such abun- 
 dance could ever come from so small an origin. The 
 view now held is that oxalic acid is derived from a 
 variety of sources, and is found in urine under a 
 variety of clinical and pathological conditions. Thus 
 it may be derived (1) directly from food by the inges- 
 tion of substances containing oxalate of lime, such as 
 certain fruits and vegetables, rhubarb, sorrel, tomatoes, 
 onions, turnips, etc. ; (2) indirectly from food, as by 
 incomplete oxydation of the saccharine amylaceous and 
 oleagineous principles of food, which, before their final 
 conversion into carbonic acid and water, yield several 
 intermediary non -nitrogenous acids, of which the chief 
 are gly collie, lactic, and oxalic acids ; (3) from increased 
 tissue metabolism ; this is probably the most frequent 
 cause for the pathological appearance of oxalate of lime 
 in the urine. The urines in these cases are generally 
 J 
 
I3P Clinical Chemistry. [Chap. iv. 
 
 of a deep orange colour, of high average specific gravity, 
 with an excess of urea and phosphoric acid, and are 
 usually turbid with mucus and urates, while the 
 deposits of oxalates are not usually persistent, often 
 disappearing for a few days, to return again in great 
 abundance. The explanation of its appearance being, 
 that the process of oxydation within the body, under 
 circumstances of increased tissue metabolism, is only 
 sufficient to reduce a certain quantity of non-nitro- 
 genous fatty acids formed within the body to their 
 lowest term of carbonic acid, and consequently oxalic 
 acid, which is one of the series, appears in the urine. 
 (4) From the mucus of the urinary passages. A veiy 
 ingenious hypothesis has been advanced by Meckel to 
 account for this formation of oxalate of lime in mucus, 
 by assuming that the mucous membrane of the urinary 
 passages becomes the seat of a specific catarrh. In 
 this catarrh a tough adhesive mucus is secreted, which 
 has a tendency to undergo acid fei'mentation, and in 
 which oxalate of lime appears when such fermentation 
 occurs. At first this oxalate of lime mucus is of gela- 
 tinous consistence, but gradually it takes up more and 
 more oxalate of lime from the decomposed urine, and 
 thus, growing more and more firm, a stony concretion 
 is at length formed. The large and numerous crystals 
 of oxalate of lime so frequently observed in the urine 
 of persons suffering from spermatorrhoea are most 
 probably derived from the mucus of the genito-urinary 
 passages ; (5) from excess of acid in the system fi'om 
 the increased formation of lactic and butyric acids in 
 intestines, the result of fermentative changes. These 
 acids absorbed from the intestinal canal into the circu- 
 lation being in excess, their reduction into carbonic 
 acid is incompletely performed, and so the intermediate 
 acid, oxalic, appears in the urine in combination with 
 lime. The urine is usually of a pale greenish colour, 
 and the quantity passed in the twenty-four hours 
 
Chap. IV.) Fnosr//ATKS. 131 
 
 normal in quantity and specific gi'avity. Its chief 
 characteristic is the deposit of crystals of oxalate of 
 lime, which are found most abundantly in the morning 
 mine passed on first rising. Owing to the presence of 
 these crystals causing irritation of the mucous mem- 
 brane of the bladder, micturition is frequent and 
 urgent, though the quantity of urine passed is not 
 large. Traces of sugar are not infrequently present, 
 and the urine occasionally contains an excess of i)hos- 
 phate of lime. This condition of urine is generally 
 associated with excessive flatulence (flatulent dys- 
 pepsia), chiefly connected with the small intestine, 
 and apparently the result of intestinal catarrh, and 
 there is usually great mental depression. 
 
 Crystals of calcium oxalate are to be recognised in 
 urine by their peculiar letter envelope shape a (Fig. 8), 
 sometimes as mere diamond points, and often as dumb- 
 bells c. In the latter case the ^ ^ 
 oxalate of lime is probably ^ gj /^S^"^ 
 derived from the urinary ^ ^ R\ Ql '^ 
 passages. The crystals dis- 4^ ^^ 
 solve in mineral acids, but ^0^ c /^ 
 not in acetic or oxalic acids, " & ^Q) ^ ^4\ 
 which serves to distinguish (^ /^, ^^ 
 them from crvstalline de- ^^ 
 posits of the Earthy phos- ^'^- ^•-^''^Sit^! ^"^"'"^ 
 phates. They ai'e insoluble 
 
 in alcohol and water. Under the blow-pipe they ai-e 
 reduced to carbonate of lime, and the residue eflfer- 
 vesces on the addition of acid. [See Urinary calculi.) 
 
 113. Phosphoric acid H3PO4. — The amount 
 of phosphoric acid passing out of the system in the 
 course of the twenty -four hours averages from 2 '5 
 grammes to 3-5 gi-ammes, and is distributed among the 
 four bases, potash, soda, lime, and magnesia, in the 
 proportion of about two-thirds combined with the 
 alkaline oxides and one-third with the oxides of the 
 
132 Clinical Chemistry. [Chap. iv. 
 
 earths. The alkaline phosphates are extremely soluble, 
 and therefore are never deposited from the urine. On 
 the other hand, the earthy phosphates are only soluble 
 in acid solutions, so that when the urine becomes 
 neutral or alkaline, they are deposited. Thus it hap- 
 ])ens that a deposit of the earthy phosphates is by no 
 means an indication that they are in excess, any more 
 than the fact that no deposit is present is an assur- 
 ance that they are being excreted in normal amount. 
 So long as the urine remains acid, a considerable 
 quantity of phosphoric acid may be passing out of the 
 system without giving evidence of its presence, whilst 
 if the urine from any cause becomes alkaline, a deposit 
 at once occurs, although the phosphoi'ic acid may not 
 be eliminated in excess. 
 
 (1) Excess of j)hosphoric acid, the salts of v)Mch 
 are not necessarily deposited. This condition has 
 long been recognised by writers. The amount of 
 phosphoric acid is enormously increased, often rising 
 from 3 grammes to as much as 8 or 10 grammes in 
 the twenty-four hours. It is chiefly in combination 
 with lime and magnesia, though the soluble phos- 
 phates are also increased, but not to the same extent. 
 The discharge of urine is also greatly increased, and 
 so is the excretion of urea. The urine may remain 
 acid throughout the course of the disease, and conse- 
 quently may be unattended with deposit ; but when 
 it becomes alkaline, which it frequently does, bulky 
 white deposits of amorphous calcium phosphate are 
 thrown down. The alkalinity of the urine in these 
 cases is due to an excess of the alkaline carbonate, 
 and when it is persistent the case is usually ex- 
 tremely obstinate. The pathology of this condition 
 is not understood, but it seems to depend on a pecu- 
 liar state of the nervous system. The increased 
 elimination may be temporary in character and 
 moderate in amount. Such cases usually occur in 
 
Chap iv.i Pi losr HATES. 133 
 
 persons who liave uiidorgone nnicli niccnt anxiety or 
 mental strain. In tliis form it often precedes the 
 onset of phthisis. Witli regard to this, Marcet's 
 analysis of pulmonary tissue in consumj^tion has an 
 important bearing, since lie has shown that a con- 
 siderable reduction of phosphoric acid and potash takes 
 place, in the soluble tissue and nutritive material 
 of the diseased as compared with the healthy lung 
 tissue. Or the increased elimination of phosphoric 
 acid may be excessive and persistent, the disease 
 running a course like saccharine diabetes, into which, 
 indeed, it often passes, but without the ai)pearance of 
 sugar. 
 
 (2) Deposits of 2')hos]')hale of lime, not, however, 
 necessarily attended ivith excessive elimination. In 
 these cases the urine is alka- 
 line from hxed alkali. The 
 urine is turbid or whey-like 
 from the presence of phos- 
 phate of lime, which deposits —p^ /- 
 on standing as amorphous >s '^ 
 granules. vSometimes, however, 
 the phosphate of lime is preci- 
 pitated in the form of fine ^^^^^""""3=5*^ 
 acicular crystals (Fig. 9), much 
 
 1 T ^ e ^ £ i''S. 9— <^rystals of Calcium 
 
 resembling some lorms or Phosphate. 
 
 lU'ic acid; they can be dis- 
 tinguished from these by their insolubility in liquor 
 j)otass8e, and solubility in hydrochloric acid. This 
 form of urine is not infrequently met with in 
 persons convalescent from febrile diseases ; and, in 
 certain forms of dyspepsia, deposits of phosphates 
 alternating with deposits of urates and uric acid are 
 often observed. Rickety children often pass urine 
 thus alternating in character. From the frequency 
 with which phosphatic deposit occurs in this disease, 
 it was eiToneously held that the phosphates were 
 
134 Clinical Chemistry. [Chap, iv, 
 
 in excess ; this is now shown to be an firc^fc^ the 
 amount of earthy phosphates not being increased 
 in rickets. Alkaline urine, when passed into a dirty 
 chamber vessel, often forms an iridescent scum on the 
 surface, owing to the formation of crystals of arnrnonio- 
 rnagnesium phosphate, caused by decomposition of 
 urea, which are minced with granules of calcium 
 phosphate. 
 
 (3) Depoaits of o/raraordo - raagnesium j)Ji.osphoM 
 {triple phosphate) Mgf XH^jPO^ + 6IL,0. We have 
 seen (page 115) that when the urine is alkaline from 
 the presence of volatile alkali 
 fammonia) we have, in addition 
 to the deposit of calcium phos- 
 phate, a crystalline precipitate 
 of magnesium phosphate in 
 combination with ammonia. 
 This salt is usually called 
 triple-phosphate. The crystals 
 Vi-4. 10.— Crystals of Am- ^^e met in different forms, but 
 ' monio-ma^nesium. the most charncteristic is that of 
 
 triangular prisms f«, Fig. 10). 
 It is sometimes deposited as feathery crystals {h, Fig. 
 10). This is especially the case when the urine 
 has been artificially rendered alkaline by the addi- 
 tion of ammonia. These crystals are sometimes 
 met with in slightly acid urine. In these cases 
 it is probable that crystals have been formed 
 originally in alkaline urine in the bladder, but 
 which has been rendered slightly acid by subsequent 
 additions of acid urine from the kidney, before the 
 mixed urine is passed ; or it may be that, subsequent 
 to emission, the urine which is passed acid undergoes 
 ammoniacal decomposition on its upper surface with the 
 formation of these crystals, while the bulk of the 
 urine remains acid. It has also been suggested that 
 the acid reaction in these cases depends upon some 
 
Chap. IV.] Phosphates. 135 
 
 s;ilt which reddens litmus paper, but whicli i« not a 
 free acid. 
 
 The quantitative estimation of phosphoric acid is 
 performed as follows : Take 100 cubic centimetres of 
 urine and add 10 cubic centimetres of saturated sodium 
 acetate solution ; divide into two portions of 55 centi- 
 metres ; each portion, of course, represents 50 cubic 
 centimetres of urine. Reserve one portion in case the 
 process has to be repesited. Heat the other to 100' C, 
 and then from a burette add 3 cc. of standard 
 solution of uranic nitrate; then, after nii.\ing well with 
 a glass rod, touch a drop of solution of pota.ssium 
 ferrocyanide, which is placed in a white dish, with 
 the wet end of the glass rod. If a reddish-brown 
 colour is developed, then too much standard solution 
 hits been used, and the process must be repeated 
 with the reserved sample; but this is not likely to 
 be the case, unless the quantity of phosphates is very 
 much below normal. If no brown stain is developed 
 then add 1 cc. more of the standard solution, and after 
 each addition touch the ferrocyanide of potassium 
 solution with the stirring rod ; when the brown stain 
 is developed record the nuniber of centimetres of the 
 standard solution that have been used. Suppose the 
 coloration is given with 18 cc, but not witli 17 cc, 
 then take the reserve sample, heat it and run into it 
 17 cc. of standard solution; then only add \ centi- 
 metre at a time, and you will tind exactly the amount 
 required to give the brown reaction, which may be 
 just over 17 cc, or just below 18 cc. Suppose it is 
 17-5 centimetres, then, as each cubic centimetre of the 
 standard solution is equivalent to '005 gramme of 
 phosphoric acid, then 17o x 005 gives the amount of 
 phosphoric acid in 50 cc. of urine, from which it is 
 easy to deduce the amount in the twenty-four hours' 
 urine. This process gives the total amount of phos- 
 phoric acid in combination with alkaline as well as 
 
136 Clinical Chemistry. [Chap. iv. 
 
 the earthy bases. In order to find how much phos- 
 phoric acid is in combination with each, we must first 
 get the total amount of phosphoric acid by the process 
 described above, and then proceed to determine the 
 phosphoric acid in combination with the earths sepa- 
 rately. This done, we deduct the amount of earthy 
 phosphates from the total phosphoric acid, the difier- 
 ence being the alkaline phosphates. To calculate the 
 earthy phosphates separately, take 100 cubic centi- 
 metres of urine, and add 20 cubic centimetres of 
 liq. ammonia, set aside for twenty-four hours. 
 Filter ofi" the precipitated phosphate of lime and 
 ammonio - magnesium phosphate, and wash them 
 thoroughly with dilute liq. ammonia. Then dissolve 
 the precipitate by means of 5 cc. of strong acetic 
 acid, and place the filter and the acid solution together 
 in a beaker and add distilled water up to 90 cc. 
 Then add 10 cubic centimetres of saturated solution of 
 sodium acetate. Pilter ; divide the filtrate into two 
 equal parts, each of which represents the amount of 
 earthy phosphates in 50 cc. of urine. Reserve one 
 portion; with the other proceed, after heating to 
 100° C, to apply the standard solution of uramic 
 nitrate, as in preceding process. The number of cubic 
 centimetres of the solution used will give the amount 
 of phosphoric acid in combination with earthy bases, 
 lime, and magnesia, in 50 cc. of urine. 
 
 114. Hydi'ocliloric acid HCl appears chiefly in 
 the urine as sodium chloride. Barral has shown that 
 the quantity of sodium chloride excreted with the 
 urine does not quite correspond with the amount 
 taken with food, about one-fifth being decomposed by 
 acid potassium phosphate to form potassium chloride 
 and acid sodium phosphate. In acute febrile diseases 
 the amount excreted by the urine is rapidly dimi- 
 nished, especially in diseases attended with exudation, 
 as pneumonia, pleurisy, and rheumatic fever ; as the 
 
Chap. IV.] Chlorides. 137 
 
 disease declines the chlorides return to the normal 
 excretion, and during convalnscenco often exceed it. 
 The avei.ige amount excreted in the twenty-four hours 
 by a healtliy adult may be reckoned a.s ranging from 
 5 to 8 grnis., varying, of course, with the quantity of 
 food. Chlorine may be estimated volumetrically by two 
 processes : by silver nitrate, or by mercuric nitrate. 
 The latter is the simplest and most reliable ; .00 cubic 
 centimetres of urine, freed from albumin if present, are 
 to be precipitated by tlie addition of an equal quantity 
 of saturated baryta solution (1 volume barium nitrate, 
 2 volumes barium hydrate), and then filtered. To the 
 solution add giadually a standardi-sed solution of mer- 
 curic nitrate; at first, the white precipitate formed after 
 each addition of the mercuric nitrate solution disap- 
 pears on shaking. When, however, all the chloride 
 present in the urine has been converted into mercuric 
 chloride, then the mercuric nitrate combines with the 
 urea and forms an insoluble compound. The solution 
 of mercuric nitrate iised for estimating chlorine is 
 weaker than that used for e.stimating urea. It is 
 standardised so that 1 cc. = '01 grm. sodium chloride. 
 The number of cubic centimetres used to produce a 
 permanent precipitate in 50 cubic centimetres of urine 
 indicates the amount of chloride of sodium present 
 in that amount. 
 
 115. Siilplniric acid H„SO.,. — Only a small 
 portion of the sulphur introduced into the body with 
 the food ajjpears in the urine, a considerable portion 
 passing off' by the lx)wels and some by the skin, in the 
 perspiration, hair, nails, and cuticle. Probably, during 
 fasting, the sulphuric acid which appears in the urine 
 is derived from the sulphur of the albuminous consti- 
 tuents of the tissues, and thus the amount of sulphuric 
 acid in the urine may be taken as the measure of the 
 metabolism of the sul))liur compounds during fasting. 
 In rheumatic fever and pneumonia the sulphuric acid 
 
138 Clinical Chemistry. [Chap. iv. 
 
 is often found considerably increased without any 
 increased ingestion of sulphur- yielding food. When 
 carbolic acid is taken or absorbed in large quantities 
 into the system the sulphates disappear, being con- 
 verted into sulpho-carbolates. The quantity of sul- 
 phuric acid in the twenty-four hours' urine is about 
 2 "5 to 3 grammes. To estimate it quantitatively take 
 50 cubic centimetres of urine, add a few drops of hydro- 
 chloric acid in order to insure complete precipitation 
 of the sulphate, then add a standardised solution of 
 .barium chloride, 1 cubic centimetre at a time, till a 
 precipitate of barium sulphate is no longer formed, 
 then, as 1 cc. of barium solution is equivalent to "01 
 gramme of sulphuric acid, the number of centimetres 
 employed indicates the amount of sulphuric acid in 
 50 cubic centimetres of urine. The sulphur in the 
 body, however, is not all oxydised into sulphuric acid, 
 and a small quantity passes into the urine in a 
 partially oxydised state. In health about 0'4 gramme 
 of unoxydised sulphur passes into the urine. In 
 disease, especially of the liver, this amount is in- 
 creased. In order to determine the amount, first 
 ascertain the quantity of sulphuric acid present, 
 then evaporate an equal portion of the urine and 
 deflagrate with potassium nitrate ; this oxydises the 
 unoxydised sulphur into sulphuric acid ; to ascertain 
 the amount of this, test with the standardised barium 
 chloride solution. The amount given will be higher 
 than when the estimation was made for sulphuric 
 acid alone. The difference represents the amount of 
 unoxydised sulphur converted into sulphuric acid. 
 
 116. Hippuric acid CgHglSTOg. — This sub- 
 stance is a normal constituent of human urine, the. 
 quantity passed in the twenty-four hours under or- 
 dinary circumstances varying from 0'8 to 1 gramme. 
 Weisman gives 1'17 grms. as the normal daily quan- 
 tity excreted. The excretion is greatly augmented 
 
Chap. IV.) JIippuRic Acid. 139 
 
 by a vegetable diet, and especially by such vegetable 
 substances as benzoic acid, cranberries, blackberries, 
 and iilunis. Consequently, we are not surprised 
 to find a considerable quantity in the urine of all her- 
 bivorous animals ; thus cows urine contains 1 per 
 cent., and horse's urine 0-38. In these animals hip- 
 puric acid often undergoes oxydation in the system, 
 and is converted into benzoic acid, which appears in 
 the urine ; thus horses at rest pass urine free from 
 benzoic acid and containing the standard quantity of 
 hippuric acid, but when put to hard work the hippuric 
 acid diminishes and benzoic acid appears. Kiihne has 
 observed that benzoic acid given to patients suftering 
 from disease of the liver passes unchanged into the 
 urine instead of being converted into hippuric acid, 
 which would have been the case under ordinary 
 circumstances. Fi*om this fact he has assumed that 
 hippuric acid is derived from the vegetable aromatic 
 constitu. nts of our food, and the place of their trans- 
 formation is the liver. Benzoic acid, given internally, 
 is said to diminish the excretion of uric acid, whilst 
 hippuric acid is increased. The excretion of hippuric 
 acid is increased in all febrile affections, also in 
 diabetes. The crystals are semi-transparent rhombic 
 plates, insoluble in cold water, but extremely soluble 
 in solutions of sodium phosphate. Boiled with strong 
 hydrochloric acid, they decompose into benzoic acid 
 and glycocin ; the latter crystallises out on cooling. To 
 obtain hippuric acid from urine, evaporate 1,000 cubic 
 centimetres of urine to near dryness, triturate the 
 residue with clean sand, and add 60 cubic centimetres 
 of hydrochloric acid ; finally extract with alcohol. The 
 acid alcoholic solution is neutralised with soda ley, 
 and evaporated to a syrupy consistence with a small 
 quantity of oxalic acid, the residue dried in a water 
 bath and treated with a large quantity of ether con- 
 taining 20 per cent, of alcohol. When the residue is 
 
140 - Clinical Chemistry. [Chap. iv. 
 
 thoroughly exhausted, the alcoholic etherial solution 
 is evaporated and the crystalline residue treated with 
 a sokition of milk of lime, and the resulting precipi- 
 tate removed by filtration. The nitrate is concentrated 
 and hydrochloric acid added ; after standing some 
 hours hippuric acid will crystallise out. The crystals 
 are collected on a weighed filter, dried and weighed ; 
 the weight gives the quantity of hippuric acid in the 
 amount of urine examined. 
 
 117. Kreatiniu 04117^30. — This base is con- 
 stantly present in human urine ; according to Neu- 
 bauer, the quantity passed into the urine in twenty- 
 four hours averages 0'6 to 1'3 grammes. It is de- 
 rived from the decomposition of kreatin in the 
 blood ; in no case has it been obtained as a primary 
 product of decomposition from any of the tissues. 
 Nawrocki has shown, by experiments, that it does not 
 occur in muscular tissue either at rest or when 
 tetanised. The crystals form oblique rhombic prisms, 
 soluble in boiling water and in 1 2 parts of cold water. 
 It is an extremely powerful base, gives an alkaline 
 reaction with test paper, and forms well-defined basic 
 double salts with zinc chloride and silver nitrate. 
 
 ABNORMAL CONSTITUENTS OF URINE. 
 
 118. AJbumiii. — Various proteid substances 
 appear in urine, the result of manifold pathological 
 conditions. 
 
 (1) Serum albumin is the form met with in 
 Bright's disease, in many depraved conditions of blood, 
 in purulent discharges from the genito-urinary tract, 
 and occasionally in persons apparently healthy, under 
 the influence of undue physiological stimuli, such as 
 excessive muscular exertion, excitement, or the inges- 
 tion of unsuitable food, etc. It is now generally 
 accepted that the Malpighian bodies are the part of 
 
Chap. IV.] Albumin. 141 
 
 the kidney by which albumin passes into the urine. 
 Tlie causes that lead to a transudation of albumin are 
 generally referred to four conditions : viz., increased 
 blood pressure, peculiarity of vascular walls, altera- 
 tions of the renal epithelium, abnormal conditions of 
 the blood, though no one of these factors alone seem.s 
 capable in it.self of fully accounting for the phenome- 
 non. In Bright's disease, albumin is most abundant 
 in cases originating in acute nephritis. During the 
 early stages it is found associated with more or less 
 blood ; as this clears up, it still continues in large 
 quantity till the attack has completely passed off, 
 indeed, often persists after all other evidence of the 
 kidney affection has disappeared, and the patient has. 
 apparently regained his usual health. When the 
 acute attack does not subside, but merges into the 
 chronic form of nephritis (the large white kidney), the 
 albumin passed is still very considerable. In the cirr- 
 hotic form (small granular kidney), the amount of al- 
 bumin present in the urine is generally small, and 
 may be often absent for days. Professor Grainger 
 Stewart thinks it probable, indeed, that cirrhosis may 
 be present as an anatomical change, without the occur- 
 rence of any albuminuria. Dr. Mahomed holds that 
 there is pre-albuminuric stage in this form of Bright's 
 disease, in which the urine for a time is free from 
 albumin. I have seen several cases tending to support 
 this view. In pui-e lardaceous disease (waxy kidney) the 
 quantity passed in the early stages is at first small, 
 but increases as the disease progresses, especially if 
 any inflammation of the tubules intervenes. Thus 
 Professor G. Stewart has watched it gradually increase 
 from a mere trace till the daily excretion reached one- 
 twelfth of an ounce. The albuminuria associated with 
 depraved condition of blood is generally associated 
 with some degree of nephritis ; but even when there is 
 no positive evidence of this, we can readily imagine 
 
142 Clinical Chemistry. [Chap. iv 
 
 how a toxic agency may affect the circulation in the 
 Malpighian tufts by diminishing the supply of oxygen, 
 or lessening the amount of nutritive material, and so 
 allow albumin to escape. The albumin derived from 
 pus cannot be distinguished from blood serum. 
 When there is no kidney disease the case can be dis- 
 tinguished by the absence of tube casts ; when, how- 
 ever, inflammatory disease of the urinary passages 
 co-exists with Bright's disease, it is impossible to 
 estimate the amount of albumin derived from each 
 cause, and our opinion with regard to the condition of 
 the kidney must be based rather on a consideration 
 of its functional power as evidenced by the excretion 
 of urea, and the specific gravity of the urine after it 
 has been freed from albumin, than from the amount 
 of this substance present in the urine. In cases of 
 temporary, or intermittent, albuminuria, the urine 
 passed at difierent periods of the day should be care- 
 fully examined, and the examination continued for 
 some time, till the conditions which lead to its 
 production are fully understood. Even after all trace 
 of albumin has long disappeared from the urine, the 
 patient should report himself from time to time, for 
 though in the majority of cases no ill results follow, 
 still this condition is sometimes a prelude to the 
 permanent and organic form of albuminuria. 
 
 The best plan of procedure in testing for serum 
 albumin is as follows : 
 
 (a) First determine the presence of a proteid or 
 albuminous substance in urine. For this purpose any 
 of the following reagents may be used :* (1) Potassium 
 ferrocyanide, with citric acid; (2) Potassio-mercuric 
 iodide, with citric acid ; (3) Mercuric chloride, with 
 
 * If the urine is turbid from mucus it must be filtered. If 
 the turbidity is due to urates, gently warming the urine will 
 clear it ; if due to phosphates, the addition of a drop or two of 
 acetic acid will re-dissolve them. 
 
Chap. IV.] Tests for Albumin. 143 
 
 citric acid ; (4) a saturated solution of Picric acid, added 
 in equal b\ilk to the urine to be tested ; (5) Concentrated 
 Nitric acid. The fir.st three tests can be conveniently 
 applied by means of Dr. Oliver's test papers, which 
 are exceedingly handy for clinically testing urine at 
 the bedside. In using these tests a citric acid paper 
 is first dropped into the test tube containing tlie urine, 
 and then the special reagent ; if albumin is present, a 
 delicate haze will difiuse through the fluid. The 
 picric acid can be carried in powder in a small box, 
 and dissolved in water when required. It is an exceed- 
 ingly delicate test for albumin, very minute traces 
 being indicated by it. It is also useful as a general 
 urinary test, since it can be made available for testing 
 for sugar (Sugar, § 119), and for the detection of 
 peptones in urine. If uric acid is in excess it is 
 thrown down by picric acid, and this precipitate may 
 be mistaken for albumin ; it can be distingixished, 
 however, by the fact that it is re-dissolved on heating, 
 whereas the precipitate given with albumin becomes 
 denser on tlie application of heat. Picric acid, too, 
 has the advantage of precipitating serum albumin 
 when modified by acid, and also alkali albumin ; at all 
 events, Di-. George Johnson, who has employed the test 
 for many years, says he has never met with a case of 
 highly acid or alkaline urine in which a precipitate 
 did not occur if albumin was present. With nitric 
 acid a zone of coagulated albumin is formed when a 
 urine containing albumin is floated on the surface, 
 which is done by placing a few drops of strong nitric 
 acid at the bottom of a test-tube, and running a little 
 of the urine carefully down the side of the glass. 
 Nitric acid as a test has been almost universally 
 adopted. It has the disadvantage, however, of being 
 an awkward reagent to carry about for bedside 
 purposes, and is not quite so delicate as picric acid. 
 Like that body, it precipitates uric acid when in excess 
 
144 Clinical Chemistry. [Chap. iv. 
 
 from the ■urine; this precipitation, however, as in the 
 other case, is distinguished by its being readily 
 dissolved by heat. 
 
 (b) Secondly, to determine that the proteid body 
 is serum albumin. The above reactions only show- 
 that an albumin of some kind or other is present 
 in the nrine, and not the variety or the form. 
 This is done by the application of special tests. 
 Now heat is the great distinguishing test for serum 
 albumin, since it is the only albumin (except sero- 
 globulin, see page 147) that coagulates at temperature 
 73° to 75° C. If, then, after having determined the 
 presence of an albumin in the urine, we wish to decide 
 that the body is serum albumin, we must heat the ur-ine. 
 This is best done by nearly filling a test-tube with fil- 
 tered urine, and applying heat to near the boiling point, 
 when, if albumin is present, a deposit varying from a 
 faint haze to a dense cloud is formed in the hot 
 portion of the tube. The advantage of applying heat 
 this way is obvious, for if there is only the merest 
 haze the difi'erence between the clear cold and the 
 slight turbidity in the heated portion is very readily 
 distinguished, especially if the tube be held to the 
 light, and the dark coat-sleeve placed behind the 
 tube ; whereas, if the whole of the urine is heated 
 a slight change may escape observation. In applying 
 the heat test it must be remembered {a) that in 
 alkaline or slightly acid urine a cloud of phosphates 
 may be precipitated on boiling them ; they clear up, 
 however, on the addition of a drop of dilute acid, or a 
 citric acid paper, whilst albumin does not. If albumin 
 is present as well, both it and the phosphates are 
 thrown down by heat, whilst the precipitate is only 
 partially re-dissolved on adding acid. If any difiiculty 
 should occur as to the amount of the partial solution, 
 a fresh sample of urine must be heated very gently 
 and kept for some time just below boiling point. 
 
ch.ip. IV.) Tests for Albumin. 145 
 
 75° to 80° C, when the albniniii alone coagulates; on 
 boiling (100° C.) there is an increase in the turhirlity, 
 the phosphate being only precipitated at the boiling 
 point. (b) Sliouhl the urine be alkaline, then the 
 scrum albumin may bo modified and appear as alkali 
 albumin or casein, in which case no coagulation, or 
 at the most only a slight turbidity, will be given by 
 heat, although the albumin may be present in con- 
 siderable amount ; if, however, we neutralise the 
 heated layer with a drop or two of dilute acid, coagu- 
 lation will at once occur ; a citric acid test-paper 
 dipped into the heated layer has the same effect. 
 {c) Similarly, if the urine is highly acid, heat will not 
 coagulate the albumin, because it is converted into 
 acid albumin or syntonin ; on neutralising the urine 
 with a droj) or two of liquor potassie precipitation 
 at once occurs ; should, however, the alkali be added 
 in excess, the precipitate is at once re-dissolved. 
 The determination of the amount of albumin present 
 in urine is often roughly performed by judging by 
 the eye the amount of coagulated material deposited 
 in the test-tube in relation to the fluid j thus it is 
 expressed at one-sixth or one-eighth, etc. This, how- 
 ever, is likely to mislead, unless the specific gravity of 
 the urine is likewise recorded, for a patient may be 
 passing a considerable quantity of albumin in a very 
 dilute but abundant urine, which ■\\T)uld of course yield 
 only a small volume of coagula, whilst a scanty but con- 
 centrated urine would yield relatively more, though the 
 quantity of albumin present might be absolutely less. 
 To make an accurate estimation the albumin must 
 be separated and weighed. The procedure is as follows : 
 Take 100 cubic centimetres of urine, place it in a glass 
 beaker, and add two or three di'ops of strong acetic 
 acid, to render it slightly acid. Place the beaker in a 
 water-bath, 100" C, for about half an hour, frequently 
 stirring to prevent clotting, then set aside to subside. 
 K 
 
146 Clinical Chemistry. [Chap. iv. 
 
 When the coagula have fallen to the bottom of the 
 vessel decant supernatant fluid into another vessel, 
 and place the coagulated material on a filter previously 
 dried and weighed, carefully removing any portion that 
 may adhere to the glass with a feather to the filter. 
 Set aside to drain, add from time to time any portion 
 of coagula that may be deposited from the super- 
 natant fluid that was decanted. When every visible 
 fragment of coagula has been transferred to the filter, 
 place it in the hot-air bath and cautiously dry ; 
 beware of applying heat too urgently at first, or it 
 will dry lumpy, and consequently take longer to get 
 rid of all the moisture, since the outer surface will 
 cake hard and so prevent the moisture from the 
 interior evaporating. When it has been in the air- 
 bath some hours withdraw, cool, and weigh,* and 
 repeat this process till it ceases to lose weight. 
 When it does, deduct the original weight of the filter 
 from the amount, and the difference will give the 
 weight of albumin in 100 cubic centimetres of urine. 
 {l^.B. — This process answers very well in ordinary 
 cases, but if the urine is scanty, and the albumin 
 is abundant, it is necessary to dilute the urine with 
 twice its volume of water, otherwise the albumin will 
 separate in clots, and carry down some of the urinary 
 material, which of course will increase the weight.) 
 
 (2) Paraglobulin and globulin. — These varieties 
 of albumin, associated with serum albumin, are met 
 with in many cases of Bright's disease, chiefly in the 
 early acute stage, when blood appears in the urine, 
 and the later stages of chronic white kidney, when 
 there is much anaemia. The globulins coagulate by 
 heat, so that to separate them from serum albumin it 
 
 * In weighing precipitates a small beaker half-full of strong 
 sulphuric acid should always be placed in the case of the 
 weighing machine, to keep the air of the chamber dry, otherwise 
 moisture will be absorbed and weight increased. The filter should 
 always be allowed to cool in this chamber. 
 
Chap. IV.) Peptones in Urine. 147 
 
 is neces.sary to employ a reagent that does not aflect 
 that body. This is effected by precipitating with 
 magnesium sulphate ; the filtrate is heated to 75'^ C, 
 which throws down the sero-albumin, by passing a 
 stream of carbonic acid through the ui-ine, which 
 should be diluted three or four times its bulk with 
 distilled water. I am not aware that the globulins 
 ever appear in ui-ine unless accompanied with serum 
 albumin ; the conditions under which both pass out 
 of the kidney seem to be identical, though in some 
 forms of temporary albuminuria paraglobulin appears 
 to be in excess of the serum albumin. 
 
 (3) Fibrin is met with in urine, associated with 
 chylous urine, from which it separates as a light 
 gelatinous clot. It is known by its power of decom- 
 posing hydrogen peroxide. After htematuria moulds 
 of the urinary tubes, consisting of decolorised fibrin 
 and fatty matter, are sometimes passed, they also 
 cause efi'ervescence with hydi'ogen peroxide. 
 
 (4) Parapeptone, or pi-o-peptone, sometimes appears 
 in urina This body is one of the intermediate 
 products of gastric and pancreatic digestion. Before 
 peptone is arrived at, according to Kiihne, anti- 
 albumose and hemi-albumose are formed. Of these, 
 anti-albumose corresponds to acid albumin or syntonin, 
 whilst hemi-albumose is probably equivalent to the 
 so-called c peptone of Meissner, which has been 
 identified with the peculiar form of albumin discovered 
 by Bence Jones in the urine of a case of osteo- 
 malacia. This body gives a precipitate with nitric 
 acid or picric acid in the cold, but which re-dissolves 
 when heated to 70° C. ; this form of albumin is 
 frequently associated with the presence of true 
 peptone in the urine. 
 
 (5) Peptones. — It has long been known that these 
 bodies often make their appearance in urine, but 
 the subject has not received in this country the 
 
■148 Clinical Chemistry. [Chap. iv. 
 
 attention it deserves. Frerichs, Schultzen, and 
 Riess have met with them in the urine of 
 cases of acute yellow atrophy and phosphorus 
 poisoning ; Eichwald in acute parenchymatous 
 nephritis ; Petri found them in twenty-eight cases out 
 of forty-one cases tested ; Gerhardt found them in the 
 urine of patients suffering from diphtheria, tertiary 
 syphilis, pneumonia, typhus, and typhoid fever; in 
 some of his cases they preceded the coming-on of 
 albumin in the urine. Gerhardt's observations have 
 been confirmed by Obermiiller. I have recorded* 
 three cases, in one of which there was slight temporary 
 albuminuria, and in two, though there was no albu- 
 min, the patients presented the appearance, and had 
 many of the symptoms, that would lead one to expect 
 granular or contracted kidney. The test for their 
 presence is the peculiar rosy red they give with alka- 
 line solutions of cupric sulphate in the cold. To 
 bring this out clearly, place about a drachm of 
 Fehling's solution in the bottom of a test-tube, and 
 float an equal quantity of urine on the surface ; 
 where the two fluids meet a zone of phosphates will be 
 deposited, above which, if peptones are present, a red 
 halo will develop. If peptones alone are present, 
 then the red is of a rosy or pink tint. If there is 
 also much albumin, then the red is more of a violet 
 hue. Now if, by means of a pipette, a drop or two of 
 picric acid is allowed to fall in, the red coloration 
 turns to deep-red, then to reddish-yellow, and finally 
 becomes yellow. It is a difficult matter to obtain 
 these bodies for examination. The plan that has 
 been usually adopted has been to precipitate them 
 with alcohol. Now albuminous peptones are not 
 quite insoluble in alcohol, whilst mucin is freely 
 precipitated by it; so that, unless mucin be previously 
 removed, this substance may be mistaken for peptone. 
 * British Med. Journal, May 12th, 1883. 
 
Chap. IV.) Peptones in Urine. 149 
 
 Again, if tlie urine contain albumin, it is very difli- 
 cult to separate it completely, a small quantity always 
 remaining even after repeated coagulation by heat. 
 The process I liave devised is a modification of that 
 adopted by Schultzen, Eiess, and Hofmeistex-. It is 
 as follows : — 500 cubic centimetres of filtered urine are 
 to be placed in a glass vessel, and 10 cubic centimetres 
 of strong acetic acid added. If mucin is present in 
 solution a turbidity ensues. The urine is allowed to 
 stand twelve hours, by which time the precipitated 
 mucin falls to the bottom of the vessel. A drop of 
 acetic acid should then be added to the supernatant 
 fluid to see if all the mucin has been thrown down ; 
 if this di'op causes a cloudiness when it is allowed 
 to fall, then more acetic acid (5 cc.) must be 
 added, and the precipitate allowed to collect; and 
 this process must be repeated till acetic acid causes no 
 cloudiness when added. The clear supernatant fluid 
 is then to be decanted off and filtered. To this add, 
 drop by drop, a concentrated solution of ferric 
 chloride, till the solution has acquired a permanent 
 red colour. Then carefully neutralise the solution 
 Avith a concentrated solution of sodium carbonate. 
 Allow the precipitate to subside ; then pour off the 
 supernatant fluid and filter it. The filtrate ought now 
 to be free from albumin, and give no reaction with 
 potassium ferrocyanide and acetic acid. The filtrate 
 is now to )je evaporated to half its bulk, and 250 
 cubic centimetres of absolute alcohol added whilst the 
 liquid is yet warm. If peptones are present, a 
 brownish precipitate is the result. The whole should 
 be kept in the water-bath (100° C.) for twenty- four 
 hours, alcohol being added from time to time. When 
 a precipitate is no longer formed, the brown substance 
 must be removed to another vessel, and boiled with 
 alcohol for twelve hours. The precipitate is then 
 collected, dried, washed with ether, dissolved in water, 
 
150 Clinical Chemistry. [Chap. iv. 
 
 re-precipitated by alcohol, again collected, dried, and 
 washed by ether. At length, after repeating this 
 process three or four times, a grey-yellowish powder 
 is obtained, which is hygroscopic, is easily soluble in 
 water. The solution is neutral in reaction, gives no 
 precipitate with potassium ferrocyanide and acetic 
 acid, turns the plane of polarised light to the left. 
 The powder, when heated to 180° C, evolves ammonia. 
 The alcoholic extracts, exhausted with ether, yield 
 to the etherial solution a brown, thin residue, out of 
 which thin crystals of tyrosin separate. 
 
 119. Sugar (glucose). — Healthy human urine 
 contains, as has been proved by Pavy, minute traces 
 of glucose ; but, in certain unnatural states of the 
 system associated with disturbance of the hepatic 
 function, a larger amount passes into the urine, in- 
 ducing a condition known either as glycosuria, or dia- 
 betes, according as it acquires a more or less marked 
 saccharine reaction and is temporary or permanent in 
 its character. The nature of the perversion of liver 
 function which leads to the increased passage of sugar 
 into the blood, and hence into the urine, and the 
 difference of degree observable in the various forms of 
 diabetes and glycosuria, are considered in the chapter 
 on the digestiA^e organs (§ 145). 
 
 Various substances produce a reaction with glucose; 
 but the tests used for clinical purposes ai-e, (1) the 
 alkaline copper test ; (2) the yeast, or fermentation, 
 test ; (3) the indigo carmine test ; (4) the picric acid 
 and liquor potassse test ; (5) polarised light. 
 
 (1) The alkaline coiJfer test. — Alkaline solutions 
 of glucose possess the power of reducing cupric salts 
 to cuprous. This property is made use of in detect- 
 ing sugar in urine. The test solution in general 
 use is that of Fehling. It is made by weighing 3 4 "6 3 
 grains of pure crystallised cupric sulphate, and adding 
 distilled water up to one litre. One cubic centimetre of 
 
ciiap. IV.) Tests for Glucose. 151 
 
 this solution is (>quivalcnt to 'OOO <;rm. of sugar. Tlio 
 alkaliiif solution is prej)arc(l by dissolving 173 gnus. 
 of pure crystallised sodio-potassiuni tartrate and 80 
 grms. of potassium hydrate in distilled water, and 
 tilling up to the measure of one litre. The copper 
 and alkaline solutions must be kejjt in separate bottles. 
 Thus prepared, the test is available for quantitative 
 as well as qualitative purposes. In testing for 
 sugar, we place equal quantities (one centimetre of 
 each solution) in a perfectly clean test-tube, and boil ; 
 then set aside for a few minutes to see if the solution 
 is in good condition and has not been impaired by 
 keeping. If in good order, it remains perfectly clear 
 and retains its deep blue colour. If faulty, it becomes 
 turbid and thick, in which case it is not available. 
 If, however, it is good, run a drop of the suspected 
 urine (which must be freed from albumin, if present) 
 down the side of the tube, and gently heat. If sugar 
 is abundant, a yellow precipitate, turning red, will be 
 formed. If no precipitate is formed, then add a drop 
 or two more urine, and so on till a bulk equal to the 
 amount of test has been added. If then there is no 
 precipitate, we may be sure that sugar is absent. 
 When the sugar is in extremely minute quantity, the 
 reduction may be veiy slight, and, instead of a red or 
 reddish -yellow, the precipitate is greenish -yellow, 
 caused by the admixture of the yellow urine and a 
 little reduced copper with the blue of the Fehling, and 
 rendered opaque by the presence of precipitated phos- 
 phates. On standing, liowever, a few grains of cuprous 
 oxide will deposit at the bottom of the tube ; this 
 distinguishes it from the greenish coloration caused 
 by inosite. Other substances, as uric acid, kreatinin, 
 etc., found in the urine besides sugar, possess when in 
 excess the propert}' of reducing cupric salts ; we must 
 be on our guard, therefore, against taking these for 
 sugar. In typical cases of diabetes or glycosuria, the 
 
152 Clinical Chemistry. [Chap. iv. 
 
 reaction in a few drops of urine is too marked to lead 
 one into error ; but, when the reduction is slight, the 
 question arises whether it is caused by uric acid or 
 sugar. To decide this question, add to the xirine a 
 solution of lead acetate ; filter ; and then test the 
 filtrate with the copper solution. If it does not now 
 give the reaction, then the former reduction was due 
 to Liric acid ; if, on the other hand, the cuprous oxide 
 is still thrown down, we may be sure the reduction is 
 due to glucose. In employing the test, care must be 
 taken only to apply gentle heat, since nitrogenous 
 matter in urine in the presence of alkalies gives off 
 ammonia, which holds the cuprous oxide in solution 
 and prevents its deposition. Again, the urine sliould 
 only be added drop by drop, since excess of glucose will 
 hold the cuprous oxide in solution. The quantitative 
 estimation of sugar by means of Fehling's solution is 
 performed as follows : Into a porcelain basin, capable 
 of holding 500 cubic centimetres, place 50 cc. of 
 distilled water, and to this add, carefully measured by 
 means of a pipette, 10 cc. of the copper solution 
 and 10 cc. of the alkaline solution, prepared as 
 directed above ; then take 5 cc. of the diabetic urine, 
 freed from albumin if present, and dilute it up to 100 
 cc. with distilled water, and place 50 cc. of this in a 
 Mohr's burette, reserving the other 50 co. in case of 
 accident or of more being required to complete the 
 process. Now very gradually heat the contents of 
 the porcelain dish to just the boiling point, and then 
 run a few drops of the diluted urine from the burette. 
 This at first is of a muddy colour, but after each 
 addition becomes redder and redder as more of the 
 copper salt is reduced. After each addition the 
 porcelain dish is tilted a little, to see if the edge of 
 the fluid has become colourless. When this is the 
 case, a few drops of the contents of the porcelain 
 basin must be withdrawn by means of a pipette, and 
 
Chap. IV.) Tests FOK Glucose. 153 
 
 passed tlu'ough a small filter into a tust tube contaiii- 
 i ing a small quantity of potassium ferrocyanide solu- 
 tion and a drop or two of acetic acid. If no brown 
 coloration is given, the process is complete; but, if 
 tluM-e is, then more of the diluted urine must be care- 
 fully added to the contents of tlio porcelain basin, till 
 the ferrocyanide solution gives no reaction. The calcu- 
 lation is made as follows : Read off the number of 
 centimetres of dilute urine used from the burette ; 
 say, for sake of example, they amount to 57 cubic 
 centimetres. Now, as tlie urine was diluted to one- 
 twentieth of its volume, 57 cc. of diluted urine are 
 equivalent to 2 "85 cc. of the diabetic urine. Again, 1 
 cc. of the copper solution is equivalent to '005 granmie 
 of sugar; and, as 10 cc. were employed for reduc- 
 tion, then 2-85 cc. of diabetic urine contained "45 
 gramme of sugar ; and, supposing the patient passed 
 3750 cubic centimetres of urine in the twenty-four 
 
 3750 cc. X -05 grm. „^ ^c, 
 
 iiours, then -^-^ ^^^ = 65"78 grammes 
 
 of sugar passed in the twenty-four hours. In other 
 
 words, the same result is obtained if we divide the 
 
 twenty-four hours' urine by the number of centimetres 
 
 of the dilute urine used from the burette ; thus 
 
 3750 
 
 — =— = 65*78 grammes of sugar. 
 
 (2) The fervientation test. — Yeast added to a 
 solution of glucose, and kept at a temperature of 25" 
 to 30° C, speedily undergoes vinous fermentation; as 
 the sugar is converted into carbonic acid, and this 
 passes otf into the atmosphere, the solution loses weight. 
 This fact has been made use of for the qiiantitative 
 estimation of sugar for clinical purposes. Two equal 
 portions of urine (4 ozs.)are placed in two 6-oz. medicine 
 bottles, and in one is placed a fragment of baker's 
 yeast, about the size of a small bean, and the mouth 
 lightly plugged with cotton wool. The two bottles 
 
154 Clinical Chemistry. [Chap. iv. 
 
 are to be kept in a warm place for twenty-four hours. 
 In the bottle in which the yeast is placed fermentative 
 action soon commences and carbonic acid formed, 
 which passes off through the cotton wool. At the end 
 of twenty-four hours the specific gravity of both 
 bottles is taken, and the difference represents the 
 amount of sugar, each degree of specific gravity lost 
 in the bottle which has undergone fermentation repre- 
 senting one grain of sugar in each ounce of the twenty-. 
 four hours' urine ; then if the patient passed 260 
 ounces of urine in the day, and the difference in the 
 specific gravity amounts to 7 degrees, then 260 x 7 = 
 1820 grains of sugar passed by the patient in twenty- 
 four hours. If French measures are employed instead of 
 English, then each degree of specific gravity lost repre- 
 sents 0"2196 gramme of sugar in every 100 cc. of urine. 
 (3) Indigo carmine test is based on the fact 
 that indogotine, the colouring matter of commercial 
 indigo, when heated with an alkali in the presence of 
 glucose and certain carbohydrates, is converted into in- 
 digo white, and which is capable of reconversion, under 
 the influence of oxygen, back into indogotine. The 
 change is repi-esented in the following equations : 
 Indogotine 2(C8H5NO) + Hj = CigHiglSTgOg indigo 
 white. Dr. Oliver has recently made this test readily 
 available by means of specially prepared test-paper. 
 A strip is placed in a test-tube and covered with dis- 
 tilled water, and heated till a blue solution is formed ; 
 a drop of diabetic urine is then introduced and heat 
 applied, care being taken not to shake the solution 
 or allow it to boil. The solution gradually becomes 
 violet, then purplish, then orange-red, then reddish- 
 yellow, and finally straw-coloured. Now on ceasing to 
 heat, and shaking the test-tube, the liquid passes back 
 through the different colours into the original blue. 
 This test is likely to prove a valuable supplement to 
 the other tests for sugar. The copper test, as is well 
 
Chap. IV.] Tests FOR Glucose. 155 
 
 known, is not rednced by all forms of sugar, nor do 
 all kinds ferniont ri.'adily with yeast; now as tlic indigo 
 reaction is given by many forms of carbohydrate, 
 it may be thus made available for distinguishing 
 between those forms of sugar sometimes present in 
 urine which give no reaction with copper, and which 
 do not readily ferment, and so help to distinguish those 
 cases from true glycosuria. 
 
 (4) Picric acid test. — When an alkaline solu- 
 tion of glucose is heated with picric acid, the liquid 
 assumes a deep red-brown colour, due to the formation 
 of picramic acid. This alibrds an extremely delicate 
 test for glucose in urine, and it has also an additional 
 advantage for clinical pur2)0ses, since picric acid is 
 a delicate test for albumin, and also that the presence 
 of albumin does not interfere with reaction for sugar. 
 In applying the test, add an equal bulk of saturated 
 solution of picric acid to the urine ; if albumin is pre- 
 sent a cloudy precipitate will form ; then add a few 
 drops of liquor potassse, and gently apply heat, the 
 solution mil gradually acquire a deep red-brown colour. 
 Nearly all urines treated in this way become darker in 
 colour, but the coloration in no way approximates 
 to that yielded by even the most minute trace of 
 sugar. Dr. George Johnson, who has paid much 
 attention to the application of the picric acid test for 
 clinical purposes, has devised an exceedingly ingenious 
 method of quantitatively estimating the amount of 
 sugar by the depths of colour yielded by this reaction 
 as compared with a standard colour for comparison. 
 His method is likely to be lai'gely used for clinical 
 investigations, as it can be quickly performed.* 
 
 Take a fluid drachm of a solution of grape-sugar, 
 
 in the proportion of a grain to the fluid ounce ; mix 
 
 it with half a drachm of liquor potasste (F.B.), and ten 
 
 minims of a saturated solution of picric acid ; and 
 
 * Brit. Med. Journal, March, 1883. 
 
156 Clinical Chemistry. [Chap. iv. 
 
 make up the mixture to four draclims with distilled 
 water. The mixture is conveniently made in a boiling 
 tube, ten inches long and three-fourths of an inch in 
 diameter, which may be marked below at the height 
 of two and four drachms. With a long boiling-tube 
 there is little risk of the liquid boiling over ; and the 
 steam, condensing in the upper cool part of the tube, 
 flows back as liquid, so that there is little loss by 
 evaporation. The liquid is now raised to the boiling 
 point, and the boiling is continued for sixty seconds 
 by the watch, so as to insure the complete reaction 
 between the sugar and the picric acid. During the 
 process of boiling, the pale yellow colour of the liquid 
 is changed to a beautiful claret red. 
 
 The liquid having been cooled, by cautiously im- 
 mersing the tube in cold water, and it having been 
 ascertained that its level is that of the four-drachm 
 mark on the tube, or, if below the mark, it having 
 been brought up to it by the addition of distilled water, 
 the colour is that which results from decomposition of 
 picric acid, by a grain of sugar to the ounce, four times 
 diluted ; in other words, it indicates one-fourth of a 
 grain of sugar to the ounce ; and this colour is a con- 
 venient standard for comparison in making a volumetric 
 analysis. The picramic acid solution, however, on 
 exposure to light, even for a few hours, becomes paler ; 
 but the colour may be exactly imitated by a solution 
 of ferric acetate, with a slight excess of acetic acid 
 and an excess of ferric chloride. The iron solution we 
 have found to retain its colour unchanged for a fort- 
 night, even when exposed to a strong light ; and we 
 expect that, when light is excluded, it may be kept 
 for an indefinite period ; and it is, therefore, a conve- 
 nient standard for comparison. 
 
 If, now, a drachm of a solution of grape-sugar, 
 containing two grains to the ounce, be mixed with the 
 same quantity of liquor potassse (half-a-drachm) as 
 
Chap. IV.] 
 
 Tests for Glucose. 
 
 '57 
 
 before, but with double the amount of picric acid (i.e., 
 twenty minims), and made up to four drachms in 
 the boiling tube, the result of boiling the mixture as 
 before, for sixty seconds, will be the production of a 
 much darker colour than when tlie one-grain solution 
 was acted upon ; but if now the dark liquid be 'diluted 
 with its own volume of water, the colour will be the 
 same as that of the one-grain solution. 
 
 The dilution is accurately done in a stoppered tube, 
 twelve inches long and three-quarters of an inch in 
 diameter, graduated into yV and yj^ equal 
 divisions (Fig. 11). By the side of this tube, 
 and held in position by an S - shaped band 
 of metal, is a stoppered tulie of equal dia- 
 meter, and about six inches long, contain- 
 ing the standard iron solution. 
 
 Sufficient of the dark saccharine liquid 
 to be analysed is poured in to occupy 
 exactly ten divisions of the graduated 
 tube. Distilled water is then added 
 cautiously, until the colour approaches 
 that of the standard. The level of the 
 liquid is then read off and noted. A more 
 exact comparison of the saccharine liquid 
 with the standard is made by pouring into 
 a flat-bottomed colourless tube, about six 
 inches long and an inch in diameter, as 
 much of the standard as will form a column of liquid 
 about an inch in height, and an exactly equal column of 
 the saccharine liquid in a precisely similar tube. The 
 operator then looks down through both tubes at once, 
 one being held in each hand, upon the surface of a white 
 porcelain slab, or a piece of white paper. In this way 
 a slight difference of tint is readily recognised, and if 
 the liquid to be analysed be found to be darker than the 
 standai'd, it is returned to the graduated tube, and 
 diluted until the two liquids are found to be identical in 
 
 Fig. 11. 
 
158 
 
 Clinical Chemistry. 
 
 [Chap. IV. 
 
 colour, when the final reading is taken. The saccharine 
 liquid having been diluted four times before it was 
 boiled, a colour eqvial to that of the quarter-grain 
 standard would indicate one grain of sugar per fluid 
 ounce. If further dilution were required (say from 
 ten to twenty divisions) the proportion of sugar would 
 
 rig. 12. — Polarimeter. 
 
 be two grains per ounce, and so on to thirty or forty 
 or upwards, or to intermediate divisions. Thus dilu- 
 tion from ten to thirty-five divisions would indicate 
 3-5 grains of sugar per ounce. 
 
 (5) Polarimetry. — Glucose possesses the pro- 
 perty of rotating polarised light toward the right. 
 This property has been made use of to determine the 
 amount of sugar present in solution, by the amount of 
 deviation observed. This is done by an instrument 
 termed a saccharometer, represented at Fig. 12. Light 
 is admitted through a Nicol's prism or folariser at 6, 
 and falls on another prism, the analyser, at a. Now 
 if these two prisms are arranged so that no light passes 
 
Chap. IV.) Blood in Urine. 159 
 
 tlirouLjh tlie analyser or sf^cnnd prism, which is rlono 
 by turning it round to a certain d(!groe ])y means of 
 screw d. Tlie instrument lieing so adjusted that no 
 light passes through tlie second prism, the tube c c is 
 then tilled with a solution of glucose, and placed be- 
 tween the two prisms a and h. Immediately light 
 passes again through the second prism a, and this 
 must be turned by means of d through a certain 
 angle till the light can again be stopped. The mag- 
 nitude of this angle is read off on scale e. Now the 
 magnitude is in direct proportion to the length of the 
 tube and the quantity of sugar in solution. If, there- 
 fore, we know the specific rotatory power of the 
 substance submitted for analysis [ajn, which in the 
 case of glucose is -f 57 "G, and have ascertained the 
 length of the tube I, and the magnitude of the angle 
 
 a 
 
 of deviation, then-p-] 1 = ^, ^^ weight in grammes 
 
 [a J I) X t 
 
 of the substance present in 1 cc. of the solution em- 
 ployed. In examining diabetic urine (freed from 
 albumin, if present), 10 cc. of solution of lead acetate 
 are added to 100 cc. of the urine, in order to remove 
 the colouring matter of the urine, and the solution 
 filtered ; the liquid is then placed in tube, the length 
 I of which, in decimeters, has been ascertained, and the 
 
 a 
 ancfle of deviation a read off, then vz-7; — -, = x grms. 
 
 [«]d 
 of glucose in each cc. of urine. 
 
 120. Blood appears in the urine under a variety 
 of conditions, (a) It may come from any part of the 
 genito-urinaiy tract, the result of local disease or 
 injuiy, as in acute nephritis, calculous disease, para- 
 sites, cancer, tubercule, etc. ; (6) or it may result from 
 certain depraved conditions of the blood itself, as in 
 scurvy, purpui-a, and the ha^maturia that often attends 
 eruptive and continued fevers of malignant type ; (c) 
 
i6o Clinical Chemistry. [Chap. iv. 
 
 or from simple passive congestion, such as occurs in the 
 obstructive forms of heart disease; ((^) from tempo 
 rary disturbance of the renal circulation, as in inter 
 raittent fever, or from mental emotion, and the like. 
 The quantity of blood passed into the urine is very 
 variable. It may be so small as only to give a smoki- 
 ness to the urine, or so great as to colour the urine 
 deep red, and to separate into large coagula in the 
 urinary passages. It must be remembered, however, 
 that a very little blood is capable of giving a very deep 
 coloration to urine. In some experiments I made in 
 1873, at the laboratory of Charing Cross Hospital, and 
 published in the Lancet, I found that only one part of 
 blood gave a decided smoky tint to 1500 parts of normal 
 urine, whilst 1 part in 500 gave a bright cherry colour. 
 Considerable haemorrhages, therefore, are best judged by 
 the amount of coagula rather than by mere intensity of 
 colour. When blood appears in urine and the blood 
 corpuscles are recognised under the microscope, the 
 condition is termed hsematuria ; when no corpuscles 
 are to be found, but only the colouring matter, then 
 it is spoken of as hsematinuria. 
 
 (1) Haematuria. — The character of the haemorr- 
 hage, together with the general and special symptoms, is 
 usually sufficient to indicate the part of the genito- 
 urinary tract from whence it is derived, thus : — 
 
 (a) Acute Nephritis. — Smoky to dark brown urine 
 persistent for some days, with granular and blood 
 casts, and excess of albumin. 
 
 (h) Renal calculus. — Often deep red from excess 
 of blood, increased by movement, and passing off 
 rapidly if the patient is kept quiet in bed, so that 
 only a few blood corpuscles can be seen in the urine. 
 Generally accompanied or immediately following a 
 severe attack of colic ; retraction of testicle on side 
 affected. Vesical calculus : haemorrhage generally 
 follows undue movement, especially jolting ; bladder 
 
Chap. IV.] Blood in Urine. 161 
 
 symptoms, prominent; deti'ction of .stone in bladder by 
 sound. 
 
 (c) Cancer of kidney. — Htematuria very abundant, 
 with large coagula, and rej^eated at irregular intervals, 
 generally tumour in loin. Cancer of bladder, frequent 
 and profuse litemorrliago, cancer cells in urine, pain 
 referable to bladder, and a tumour may be discovered 
 "with sound. 
 
 {d) Morbid conditions of the blood. — Hsemon-hage 
 often ])rofuse, but rai'cly attended with formation of 
 clot. General constitutional symptonis manifest. 
 
 (e) Intermittent ha-maturia. — The blood passes at 
 very irregular inter\als, is generally associated with a 
 considerable quantity of albumin and a definite rise 
 of temperature. In these cases there is usually a 
 history of ague, if the disease is not actually in 
 progress ; it is sometimes associated with intermittent 
 chylui'ia or gout. 
 
 (2) Hamatinuria. — In these cases only the 
 colouring matter of the blood is present, no blood 
 corpuscles, or only a few, are to be found. The 
 attacks come on in paroxysms, attended Avith a chill, 
 and genei'ally accompanied Avith some degree of nausea 
 and slight jaundice. The urine has a port-wine 
 colour, and is usually passed clear. On standing 
 it deposits a granular sediment, consisting of a few 
 tube casts and fibrinous cylinders, epithelium, crystals 
 of calcium oxalate, in some cases crystals of htematin 
 have been observed. From the fact that the spectrum 
 of this kind of urine invariably shows the charac- 
 teristic bands of htemoglobulin, many writers desig- 
 nate the disease hsemogiobiuuria. But in addition, 
 however, to the bands in D and E characteristic of 
 hsemoglobulin, there is invariably a third present near 
 c, Avhich corresponds with that given by methsemo- 
 globin in acid solutions. {See Fig. 4, § 95.) Formerly 
 metluemoglobinwas supposed to be per-oxy-htemoglobin, 
 
 L 
 
1 62 Clinical Chemistry. [Chap. iv. 
 
 in whicli case by reduction methsemoglobin ought 
 to yield oxy-Ksemoglobin, but it yields, however, re- 
 duced hsemogiobin. This and other considerations 
 make it probable that methsemogiobin, instead of con- 
 taining more oxygen, actually contains less than oxy- 
 hsemogiobin, and that as regards iron, whilst this 
 body is at its minimum in oxy-hsemoglobin, it is at its 
 maximum in methsemogiobin. These considerations, 
 therefore, make it probable that the oxy-hsemoglobin 
 is undergoing a downwai'd change into hsematin. 
 The pathology of the disease is still obscure, though 
 the iuteresting researches of Jaffe and MacMunn 
 on the origin of the urinary pigments seem to 
 throw some light on it If the effete hsemogiobin 
 is converted in the liver into hsematin and then into 
 bile pigments, one of which, urobilin, is oxydised 
 into choletelin, which appears in the uiine ; and if 
 this conversion does not always take place, it may 
 be owing to some functional disturbance of the 
 liver, the effete hsemogiobin may escape conversion 
 in the liver, and be eliminated by the kidney, as 
 hsemogiobin undergoing the downward change into 
 hsematin before conversion into choletelia (§ 100). 
 That there is some disturbance of hepatic function 
 is indicated by the jaundice attendant on this con- 
 dition. 
 
 The tests for blood in urine. When due to hsema- 
 turia, the detection of blood corpuscles by the micro- 
 scope affords the best and most positive indication of 
 the presence of blood. These, however, vary in 
 shape. If the urine is moderately acid they retain 
 their natural form a considerable time, but they 
 become jagged at their edges, lose colour, and no 
 longer adhere together. If the blood corpuscles 
 become dissolved, then we may try Heller's hsematin 
 test, which consists in boiling the urine with a 
 concentrated solution of caustic potash, when the 
 
Chap. IV.] Bile in Urine. 163 
 
 phosphatps carry down the liaMuatin as a rofldish- 
 brown pr(>ci|iitate, wliich by tran.smitted liglit ha.s a 
 greenish tint ; and wliieh precij>itate, treated with 
 .sodium cidoride and acetic acid, yields crystals 
 of hiemin (Fig. 3, § 95). The guiacum test is 
 best applied by filling a test-tube one-third with 
 tincture of guiacum and adding a few drops of the 
 suspected urine, then float about a di'achm of etherial 
 solution of peroxide of hydrogen on the surface, and 
 at the line of junction, if blood is present, a delicate 
 blue colour is developed. This test, however, is not 
 to be depended on, except as a general one, since often 
 extraneous substances besides blood may give the 
 reaction in urine. If any doubt exists, the spectro- 
 scopic examination will reveal characteristic bands of 
 oxy-hajmoglobin, reduced haemoglobin, meth?emoglobin, 
 or h;ematin, according to circumstances, and the 
 degree of decomposition that has occurred. 
 
 121. Bile. — The conditions which lead to the 
 appearance of bile in the urine are discussed in 
 chapter v., § 138. Urine containing bile varies from a 
 deep brownish-red to the colour of London porter. 
 A linen rag dipped in it acquires a yellow stain. 
 This coloration is due to bile pigment. The reaction 
 for this is readily shown by placing on a white 
 plate or dish a few drops of the urine, and 
 near it a few drops of nitric acid to which 
 one drop of suli)hui'ic acid has been added (to form 
 free nitrons acid), and then allow the two fluids to 
 mix. If bile pigment is present, a play of colour is 
 observable, of which the green tint is characteristic of 
 bile pigment {Gmelin's test). Bile acids are present, 
 as well, in the urine of some cases of jaundice. 
 They are detected by adding a few grains of glucose 
 to the urine, and then allowing the solution to run 
 down the side of a test in which a little concen- 
 trated sulphuric acid has been placed ; a purple 
 
164 Clinical Chemistry. [Chap. iv. 
 
 reaction {Pettenhoffer'' s test) will develop if they are 
 present. As some other substances give this reaction, 
 if there is any doubt the bile acids must be separated 
 from the urine by evaporating it to a thick syrup, 
 extracting with ordinary alcohol, evaporating the 
 alcoholic solution, and treating the residue with 
 absolute alcohol. Evaporate this solution, and dissolve 
 the residue in distilled water, and precipitate the 
 solution with neutral and basic lead acetate. The 
 precipitate is dissolved in water, and decomposed with 
 hydrogen sulphide, and filtered. The filtrate is 
 treated with excess of sodium carbonate, and concen- 
 trated. On standing, long needle-like crystals of 
 glycocholate of soda will form, with oily globules of 
 taurocholate of soda. 
 
 122. Chylous urine. — In the disease known as 
 chyluria the urine has a milky appearance, sometimes 
 slightly tinged with blood, and yields a delicate 
 fibrinous clot. On standing this clot comes to the 
 surface of the urine, and forms a distinct, jelly-like 
 layer. This clot possesses the property of fibrin, of 
 decomposing peroxide of hydrogen. Besides the 
 addition of this abnornial ma,tter, the urine is little 
 altered in its other characters. After the separa- 
 tion of the clot, the blood, the extraneous albumin, 
 and the removal of the fatty matter by extraction 
 with ether, I h^ve found the urea normal in propor- 
 tion, though the amount of water is relatively 
 increased. The chylous matter is apparently derived 
 from the lymphatics, probably due to some lesion of 
 those connected with the kidney. The disease is 
 sometimes ]Dersistent, but frequently it is occasional 
 and intermittent, There are cases on record in 
 which the urine was observed milky on a few occasions 
 only, but never afterwards made its appearance. The 
 most completely recorded case of typical persistent 
 chyluria, associated with filaria in the blood, is by 
 
Ch.np. I V.J 
 
 CUVLURIA, 
 
 I ^^5 
 
 Dr. Stephen Mackenzie* Bricgoif has giveti some 
 very ('nm]il('tp aiialysos of the night urine; two, the 
 m.'ixiiiiiuii aiul iiiiiiiimiin, arc hero appended : 
 
 
 Maximum 
 
 in 
 100 piirts. 
 
 Minimum 
 
 in 
 100 parts. 
 
 Fats. 
 
 Albumins ..... 
 
 Urea 
 
 Uric acid 
 
 Sodium chloride 
 
 Sulphates .... 
 
 0-725 
 
 0.798 
 
 3-4 
 
 0-03 
 
 1-7 
 
 0-22 
 
 006 
 
 0-681 
 
 3-7 
 
 0-03 
 
 1-4 
 
 0-23 
 
 Quantity of urine , 
 Specific gravity 
 
 400cc. 
 1-OlGcc. 
 
 300cc. 
 1-025CC. 
 
 Both urines contained peptones and traces of indican. 
 The fatty matters consisted of ordinary fatty matter, 
 lecithin, and cholesterin. To examine a chylous 
 urine, filter off the coagulum, and exhaust it thoroughly 
 with ether, water, and alcohol till quite free from fat 
 and albumin; dry and weigh. Agitate the ui'ine 
 with successive quantities of ether till no more fat 
 is taken up. Evaporate the etherial solution in a 
 weighed platinum capsule, weigh the dried residue, 
 which gives amount of fatty matten (For separate 
 determination of the nature of these fatty matters 
 see § 99.) The urine freed from fatty matters can 
 then be examined quantitatively for albumin (§ 118), 
 peptones (§ 118, ISTo. 5), urea (§ 110), uric acid 
 (§ 111), chlorides (§ 114), sulphates (§ 115), phos- 
 phates (§ 113). 
 
 Apart from chyluria the urine often assumes a 
 milky appearaiace, from the presence of fatty matters 
 
 * Path. Soc. Trans., vol. xxxiii., p. 394. 
 t Zeitsch. Phys. Chemie, p. 411, 1880, 
 
1 66 Clinical Chemistry. [Chap. iv. 
 
 in a state of extremely fine subdivision ; the urine 
 in these cases is generally slightly albuminous, and 
 often gives the peptone reaction with cupric sulphate. 
 In Bright's disease, fatty matters may appear in 
 the urine, apparently derived from the degenerated 
 epithelium of the tubules. I have met with a small 
 quantity of fatty matter in the urine of a patient dying 
 of acute diabetic coma. Plates of cholesterin are 
 sometimes met with as a urinary deposit. 
 
 123. Cystin CsH^NSO^. —According to Dr. 
 Bence^ Jones, cystin is constantly being separated in 
 the healthy organism, immediately undergoing trans- 
 formation into sulphuric acid, carbonic acid, and 
 urea. Whenever this chemical transformation is 
 arrested cystin appears in the urine. As the com- 
 position of cystin is C3H.NSO2, the proportion of 
 nitrogen to carbon is four to twelve ; in uric acid 
 C5H4N4O3 it is four to five ; and in urea CH4NaO four 
 to two : therefore twelve, five, and two are the indices 
 representing the different amounts 
 of suboxydation in cystin, uric acid, 
 and urea respectively. Dr. Bence 
 Jones thus regards cystin as repre- 
 senting the smallest degree of the 
 oxydation of the albuminous prin- 
 ciples, in the same way that sugar 
 in diabetes represents the least 
 degree of oxydation of the amyla- 
 ^^'Crystais,^*"^ ceous principles. Cystin, however, 
 as a urinary deposit is extremely 
 rare. When it appears it forms a whitish or faAvn- 
 coloured sediment, which is dissolved by ammonia, 
 and from which on evaporation it is deposited va, 
 hexagonal plates (Fig. 13), and which are insoluble 
 in acetic acid. Heated in a solution of lead ace- 
 tate, a precipitate of lead sulphide is formed, owing 
 to the sulphur contained in cystin. The pathological 
 
Chap. IV.] XaNTIIIN. 1 67 
 
 significance of cystin in uriiu^ is not yet determined. 
 I Imve met witli it in the urine? of strumous chil- 
 dren, and in adults su(l"orinijf from di.sea.se of the liver. 
 It sometimes is retained in the urinary passages and 
 forms a calculus. 
 
 12-1. Xaiilhiii C-JI ,N|0o is a constituent of certain 
 rare urinary cak;uli, antl Dr. Bence Jones has re- 
 corded an interesting ca.se of xanthin gravel in a boy 
 aged nine years. The xanthin calculus removed by 
 Langenbeck was also from a boy. Dr. Bence Jones 
 considers that the xanthin diathesis will be generally 
 found to occur in youth, as it is in the early period of 
 life the greatest chemical variations of the body are 
 to be expected, and the most imperfect oxydation of 
 xanthin into uric acid most likely to occur. To 
 separate it from urine, add baryta water till a preci- 
 j)itate is no longer thrown down; filter, and evaporate 
 the filtrate to a syrup, and allow it to crystallise. 
 The mother liquor, after the removal of the crystals, 
 is boiled with cupric acetate, and the precipitate thus 
 formed is removed by filtration, 
 washed, and dissolved in warm nitric J\^() 
 
 acid. This acid solution is precipi- k^^ Iv^ A 
 
 tated by silver nitrate, and the result- \^^ ^^(1 a 
 ing precipitate washed and crystal- ^^^^^^ t^ 
 lised from dilute nitric acid, and the f)^f\^^%^^ 
 crystals washed with ammoniacal ^V'|t') (/\l /^ 
 silver solution, and suspended in v) \) /) r^ 
 
 water. The aqueous solution is to (j .^^ \ I 
 
 be decomposed with snlphydric acid, ^v^^ n ^^ & 
 filtered, and the filtrate evapo- /^ \\ y7 
 rated ; the residue yields xanthin. \} 
 
 Xanthin forms white scales, some- „. , , „ , , . 
 
 . . ' FiL'. 14-. — AnutuiJi 
 
 what resembling beeswax m appeal'- ' Crystals, 
 ance. Deposited spontaneously from 
 urine it occurs in lemon-shaped plates (Fig. 14, a)\ 
 these, dissolved in hydrochloric acid and the solution 
 
1 68 Clinical Chemistry. [CUap. iv. 
 
 evaporated, yield prismatic and hexagonal crystals (6). 
 Xanthin is insoluble in water, alcohol, and ether; 
 soluble in alkaline solutions, from which it is deposited 
 by a current of carbonic acid gas ; and in strong 
 mineral acids. Burnt in air, it gives off the odour 
 of scorched hair. Evaporated with nitric acid on 
 platinum foil, and the residue moistened with liquor 
 potassse, it yields a dark purple colour. Xanthin 
 gives white precipitates, with mercuric chloride and 
 silver nitrate. Dissolved in hydrochloric acid, it gives 
 with platinic chloride a yellow crystalline precipitate. 
 
 125. Hypoxanthin CgH4]S'40 has been found 
 in the urine of patients suffering from leucaemia; to 
 separate it, add baryta water and filter off the pre- 
 cipitate. To the filtrate ammoniacal solution of 
 silver nitrate is added, and the greyish- white precipi- 
 tate collected on a filter and washed. The precipitate 
 is then to be suspended in water, decomposed with 
 sulphydric acid, the mixture boiled for some time, 
 and filtered while hot. The filtrate is next evapo- 
 rated to dryness, the residue contains uric acid, 
 xanthin, and hypoxanthin. To separate the uric acid 
 and xanthin, the residue is to be dissolved in dilute 
 sulphuric acid, boiled, and filtered whilst hot ; to the 
 filtrate, when cold, mercuric nitrate is added and 
 filtered. To the filti'ate some ammoniacal solution of 
 silver nitrate is added ; the precipitate consists of 
 hypoxanthin nitrate and silver oxide. This is decom- 
 posed with sulphydric acid and hypoxanthin is preci- 
 pitated as a white, imperfectly crystalline powder, 
 rather more soluble in water and alcohol than xanthin. 
 It dissolves freely in acids. 
 
 126. lieucin CgHigNOg has generally been met 
 with in the urine in cases of acute yellow atrophy 
 of, the liver, in cirrhosis of that organ, and in severe 
 cases of small-pox and typhus. Dr. Anderson, how- 
 ever, has found leucin somewhat frequently in urine 
 
Chap. IV.] LEUCItf. i6g 
 
 uudor less severe conditions. He believes that both 
 leucin and tyrosin are found in the urine under numer- 
 ous diirereut pathological conditions, whether affecting 
 the liver intrinsically, or from without ; and that as 
 often, or as soon as the jiatient recovers, these substi- 
 tution products for urea Hrst diminish in amount and 
 then disajipear (^Med.-Chir. Soc. Trans., vol. Ixiii., 
 p. 245). Without entirely agreeing with all the 
 author's conclusions, I believe we should find leucin 
 more frequently if we looked for it. Leucin, as well 
 as tyrosin, has an interest in consequence of its 
 formation dui-ing pancreatic digestion. When present 
 in urine, it is only required to evaporate about 
 five ounces of that fluid to a thin syrup, and, when 
 cold, leucin in the shape of oily cii'cular-looking discs 
 will be deposited. 
 
 Leucin obtained from urine is not crystalline, 
 but forms circular oily-looking discs (Fig. L5, a) which 
 float on the surface of water ; 
 they generally have a somewhat 
 yellowish appearance, owing to 
 the colouring matter of the urine. 
 If this form of leucin be dissolved 
 in boiling alcohol, the solution on 
 cooling will deposit leucin in j,jg_ jg _„^ Lencin; 
 crystalline plates. Leucin is de- b. Tyrosin. 
 
 posited from its alcoholic solution 
 
 in white shining plates, greasy to the touch, lighter 
 than water, and much resembling cholestei-in in 
 appearance ; it is distinguished from that substance 
 by its insolubility in ether. It is slightly soluble 
 in cold water, and very soluble in boiling water, 
 soluble in 600 parts of cold absolute alcohol, very 
 insoluble in ether, melting point 170° C. ; is decom- 
 posed by nitrous acid, leucic acid being formed and 
 nitrogen given off. Distilled with dilute sulphuric 
 acid and manganese peroxide, it yields valei'O-nitrile, 
 
170 
 
 Clinical Chemistry. 
 
 [Chap. IV. 
 
 carbonic acid, and water. Fused with caustic potash 
 it is transformed into potassium valerate, hydrogen, 
 and ammonia. 
 
 127. Tyr©siM CgH^NOg is invariably associated 
 with leucin. To obtain it from the urine ; precipitate 
 the colouring and extractive matters with basic 
 lead acetate, and filter; decompose the filtrate with 
 sulphydric acid and filter ; the clear filtrate is to be 
 concentrated, and, on cooling, crystals of ty rosin will 
 be deposited. The crystals form long prismatic needles, 
 which chister together to form stellate groups \ some- 
 times, when obtained from urine, these groups are so 
 closely aggregated together as to form balls of spicu- 
 lated needles (Fig. 15, 6), The crystals are sparingly 
 soluble in cold water and alcohol ; soluble in boiling 
 water and in acid and alkaline solutions, the solubility 
 being increased by the presence of extractive matters ; 
 insoluble in ether. 
 
 Tyrosin treated with nitric acid turns an orange- 
 red colour, which becomes yellow on heating ; this 
 touched with a drop of liquor sodse acquires a red tinge. 
 
 128. Mmcus and pus. — Pure mucus forms a 
 clear translucent mass; mingled with it, however, are 
 
 epithelial cells derived from 
 various parts of the genito- 
 urinary tract (Fig. 16) and 
 pigmentary particles. Per- 
 fectly healthy urine always 
 contains a small quantity 
 of mucus, which, if the 
 urine be allowed to stand 
 in a glass vessel, will be 
 seen diffused as a fine cloud 
 in the lower stratum. The 
 epithelium is composed of 
 bladder epithelium (Fig. 
 
 Fig. 16. — Epithelium in Urine. 
 
 1 6, d), mixed, in the case of women, with the epithelium 
 
Chap. IV.] Pus AND MuCUS. 1 7 I 
 
 from the vagina. "When mucus is increased in quantity 
 by any morbid condition of the genitourinary tract, 
 we have in addition mucus corpuscles, and epithelium 
 from the part of the tract aflected ; as small rounded 
 renal cells (Fig. IG, a) and casts in nephritis; larger 
 rounded cells (Fig. IG, 6) from the pelvis and kidm^y; 
 columnar cells (Fig. 16, f) from the ureter, or urethra ; 
 or large cancer cells in cancer of bladder, and granular 
 masses in tubercular disease. Pus is generally present in 
 the urine containing an excess of mucus ; its presence 
 is indicated by traces of albumin derived from the 
 liquor puvis. To distinguish diO'ei'entially between pus 
 and mucus, when both are present, is oftentimes some- 
 what diflicult, especially if, in addition to the albumin 
 deri\ed from the liquor pui'is, there is albuminuria 
 from kidney disease. The following reactions will aid 
 us in coming to a conclusion : {a) the addition of 
 liquor potassaj to a urine containing an excess of 
 pus renders it thick and gelatinou.s, whereas, if mucus 
 be in excess it is rendei-ed thinner ; {h) mercuric 
 chloride added to the urine, if pus is present, the 
 pyin is precipitated, but not mucin ; the precipitate 
 should be filtered oil', and if mucin is present it will 
 be precipitated from the filtrate on the addition of 
 acetic acid ; (c) under the microscope it is difficult to 
 distinguish mucin corpuscles from pus corpuscles and 
 other young cell-forms, all swelling up and losing their 
 granular surface, whilst the niiclei become more visible 
 on the addition of acetic acid ; if, however, mucus is 
 in excess, a coagulation will often occur in the fluid 
 when a drop of acetic acid is added, from precipitation 
 of the mucin. The clinical character of the urine also 
 may afibrd a clue. When mucus is in excess, the urine 
 s})eedily undci'goes acid fermentation and becomes 
 more acid, which speedily passes on to ammoniacal 
 fermentation. Purulent urine is usually neutral, 
 and undergoes alkaline fermentation slowly. Urines 
 
T]2 Clinical Chemistry. [Chap. iv. 
 
 containing an excess of mucus, if acid, friequently de- 
 posit the mucin in small shreds and cylinders, these 
 are soluble in liquor potassse. On the other hand, 
 purulent urine, when alkaline, deposits white ropy 
 strings, which are soluble in acid. 
 
 Extraneous substances. — Fungi, entozoa, hair from 
 dermoid cysts, foetal bones, etc., may all find their 
 way into the urine, and are best recognised by their 
 microscopic appearance. Sand, cane-sugar, mortar, 
 etc., may be added by hysterical patients for the pur- 
 pose of deceiDtion. 
 
 129. Detection of lead in nrine. — Many 
 organic and inorganic poisons a-re eliminated by the 
 kidneys aad pass into the urine. In cases of poison- 
 ing by these substances, however, it is more usual to 
 examine the vomit and faeces than the urine, or if the 
 patient has died, to seek for them in the tissues. The 
 method to be employed in these cases is described 
 § 151. It is convenient here to describe, however, 
 the process for the detection of lead in urine, as it 
 is frequently required for clinical purposes in cases of 
 plumbism, to watch the gradual elimination of lead 
 under treatment, especially after the administration of 
 potassium iodide. As the amount of lead is often 
 extremely minute, the whole twenty-four hours' urine 
 should be employed. This should be evaporated to a 
 treacly residue in a large porcelain dish, and this 
 transferred to a platinum or porcelain crucible, and 
 heat applied, gently at first, till nothing but a grey ash 
 is left. The soluble salts are then removed by the 
 addition of boiling distilled water, till a drop of the 
 washings gives no residue when evaporated on a 
 glass slide. The washings are to be examined with 
 sulphydric acid, to see that they contain no lead. 
 The residue is then treated with equal parts of 
 distilled water and niti'ic acid, and the mixture boiled 
 for a few minutes ; it is then filtered, and the filtrate 
 
Chap, v.] Saliva. 173 
 
 tested for lead: (1) By the addition of sulphydric 
 acid, giving a black sulphide of lead ; (2) potas- 
 sium iodide, a yellow precipitate of lead iodide ; (3) 
 potassium chromate, a yellow precipitate of lead 
 chromate, insoluble in dilute acids. These precipitates, 
 together with the residue not dissolved by the nitric 
 acid, and the precipitate given by the sulphydric acid, 
 if any, with the first washings with hot distilled water, 
 must be placed on a filter and dried. The dried resi- 
 due mixed with sodium carbonate, and the mixture 
 ])laced on charcoal and fused by the blow-pipe, when 
 a bead of metallic lead will be obtained, which repre- 
 sents the whole of the lead present in a metallic state 
 in the twenty-four hours' urine. 
 
 130. Urinary calculi. — {^See Morbid products, 
 chapter vi.) 
 
 CHAPTER Y. 
 
 MORBID CONDITIONS OF THE DIGESTIVE SECRETIONS. 
 
 131. Saliva, as presented for clinical exami- 
 nation, is mixed with oral mucus, and oftentimes con- 
 tains portions of food in a state more or less decom- 
 posed. It may be obtained fairly pure by directing 
 the patient to wash his mouth out thoroughly 
 with a dilute warm solution of bicarbonate of soda, 
 and afterwards ynih. cold spring-water. The inside of 
 the mouth should then be lightly brushed with a 
 glass rod moistened with a little dilute acid, when the 
 mouth will fill with a considerable amount of clear 
 viscid fluid. To obtain saliva absolutely pure, 
 however, a small canula should be introduced into 
 the ducts of the respective glands. The saliva 
 obtained from the parotid and submaxillary glands 
 
174 Clinical Chemistry. [Chap. v. 
 
 diflfers in quality ; the former being ricli in ptyalin 
 and poor in mucin, whilst the submaxillary gland 
 contains a considerable amount of mucin, and but 
 little ptyalin. The physiological effect of the 
 stimulation of the nerves supplying these two glands 
 has been thoroughly investigated and recorded in 
 physiological text - books. Here it will only be 
 necessary to recall the results. Thus, stimulation of 
 the parotid by Jacobson's nerve, leads to a watery secre- 
 tion, containing little albumin, ptyalin, and salts. Irri- 
 tation of the sympathetic causes no secretion, but irri- 
 tation of both Jacobson's nerve and the sympathetic at 
 the same time, gives rise to an abundant secretion, in 
 which the organic constituents abound, but the salts 
 are only slightly increased. With the submaxillary 
 gland, stimulation of the chorda tympani produces an 
 increased flow of saliva ; if, however, the stimulation 
 be directed to the sympathetic filament exclusively, 
 the secretion, though abundant, becomes thicker and 
 more gelatinous than from stimulation of both filaments. 
 Section of the nerves without stimulation often leads 
 to the discharge, for days and weeks together, of a thin 
 aqueous saliva, the so-called paralytic saliva. Atropin, 
 as is well known, paralyses the action of the gland, 
 but other substances, such as pilocai'pin and eserin, 
 stimulate the secretion. Langley has shown {Journal 
 of Physiology, vol. i.), that by injecting atropin into 
 the duct of the submaxillary, the secretion can be 
 stopped, but by injection of pilocarpin it is re- 
 stored. The sublingual and buccal glands also 
 secrete saliva ; but in the human subject their 
 secretion cannot be obtained separately for examina- 
 tion, since it involves tying the ducts of the other 
 glands. 
 
 The mixed saliva has the following approximate 
 composition in 1,000 parts : Water 994-94 ; Solids 5'06 
 (ptyalin 1*2, mucin 1"3, fatty matters 1"1, salts 1"6). 
 
Chap. V.) Saliva. 175 
 
 The ptAjalin, or diastatic ferment, may be separated 
 approximately pure by precipitating fresh saliva with 
 dilute normal phosphoric acid, and then adding lime- 
 water ; filter otl' precipitate, and dissolve it in distilled 
 water, from which it is to be precipitated by alcohol, 
 collected on a lilter, washed repeatedly with a mixture 
 of alcohol and water, dried, and weiglicd. As ptyalin, 
 however, has never been obtained quite pure, its 
 chemical composition and reactions are doubtful, 
 except its energetic action on starch, which it converts 
 into maltose and glucose. Mucin may be obtained by 
 allowing saliva to fall into a beaker containing some 
 dilute acetic acid, when it will deposit in stringy 
 flakes ; these should be collected on a filter, and 
 washed with alcohol, dried, and weighed. Pure 
 saliva also contains traces of serum albumin and 
 serum globulin. The fatty matters are estimated 
 from the etherial residue as for blood (§ 93). The 
 inorganic residue is estimated (a) from the bases 
 by incinei'ation (§101); (h) from the acids by volumetric 
 determination directly from the saliva, after the 
 removal of the organic constituents, as with the 
 estimation of phosphoric, hydrochloric, and sulphuric 
 acid in urine (§§ 113, 114, 115). The salts consist 
 chiefly of calcium phosphate, and carbonate, and are 
 deposited, unless care is taken, roinid the teeth as tartar; 
 .sometimes they deposit in the salivary ducts, and form 
 a calculus. The saliva also contains potassium sulpho- 
 cyanate, which is of some interest, from a medico-legal 
 point of view, in opium poisoning (§§ 83, 136). 
 
 The variation in the quality and quantity of saliva 
 excreted under various morbid conditions has been very 
 inadequately studied. The following are the chief facts 
 of importance that have been ascertained. The average 
 daily amount excreted has been placed at 1,500 grms. ; 
 this is probably too high, and 800 to 900 grms. is nearer 
 the mark. The daily excretion is increased by dry 
 
176 Clinical Chemistry. [Chap. v. 
 
 food. The excretion is diminished in pyrexia, and by \ 
 the action of certain drugs, particularly belladonna. • 
 Claude Bernard found that dilute alcohol, dilute 
 alkaline solutions, and saliva were all powerful 
 excitants of the gastric secretion when introduced 
 into the stomach by means of a gastric fistula; but of 
 the three saliva was the most powerful. Saliva, then, 
 must be regarded as having a twofold function ; its 
 diastatic action, and as an exciter of gastric secretion. 
 Diminution of its secretion must therefore lessen the 
 digestive powers, both as regards the albuminoiis as 
 well as the starchy constituents of the food. The 
 saliva of new-born infants has no diastatic action on 
 starch. The normal reaction of saliva is alkaline, it 
 is often neutral, sometimes acid. The acidity in most 
 cases is due to decomposition of organic substances in 
 the moutli, though in some diseases, as diabetes, acute 
 rheumatism, and mercurial salivation, the saliva is 
 acid as it comes from the ducts of the glands. The dias- 
 tatic action of saliva is best manifested in dilute alkaline 
 solutions at 40° C, but it also acts in neutral and very 
 dilute acid solutions ; strong alkalies and acids, and 
 temperatures above 70° C, stop its action entirely. 
 In conditions of debility, and under the influence of 
 certain drugs (sialogues), of which mercury, pilo- 
 carpin, and eserin are the chief, the amount dis 
 charged in the twenty-four hours is greatly increased. 
 In water brash the aqueous discharge from the mouth 
 undoubtedly proceeds in great measure from the salivary 
 glands. Salivation is often met with in hysterical 
 females, and is sometimes of an intermittent character. 
 I have noticed profuse salivation after injury to the 
 upper part of the food tube in a case of attempted 
 sulphuric acid poisoning ; the sialorrhsea came on some 
 time after the separation of the eschars and healing of 
 the ulcers. Physiological remedies were tried without 
 avail, and the salivation contintied till the patient's 
 
Chap, v.] S.l LIVA TION. I 7 '/ 
 
 general health was restored, when it gradually subsided. 
 Altered saliva is often retched up from the stomach 
 in cases of chronic gastric catarrh, especially that form 
 dependent on alcoholism. This retching is most 
 frequent in the morning, and stringy masses are 
 bi'ought up. These consist of mucin derived from 
 the saliva swallowed during sleep, and deposited from 
 it by th6 action of the acetic and other acids, produced 
 by fermentative action going on in the stomach, just 
 in the same way as mucin is thrown down from saliva 
 when dropped into a vessel containing dilute acetic 
 acid. 
 
 Salivation, as is well known, follows the continued 
 use of mercury ; and extremely minute doses will, \vith 
 some people, rapidly induce the condition. In most 
 instances we can trace the salivation to the use of the 
 drug ; but in some cases, when it has been accidentally 
 introduced into the system, either by the stomach 
 in quack medicines, or through the skin by handling 
 some material the deleterious nature of which was 
 unknown, it becomes necessary to examine the saliva 
 in order to discover the presence of mercury, and so 
 get a clue to the cause of the salivation. 
 
 132. Detection of mercury in saliva. — For 
 this purpose the saliva is to be collected for twenty-four 
 hours, and dilute hydrochloric acid (one part of acid 
 to nine parts of water) added to it. The mixture is 
 heated for two hours in a water-bath, filtered, and the 
 filtrate, which should be labelled a, concentrated to 
 half its bulk. The precipitated matters in the filter 
 are then placed in a beaker, filled three parts full 
 with dilute hydrochloric acid (one part acid to six 
 water), and the whole heated over a water-bath, 
 adding from time to time small quantities of potassium 
 chlorate, and constantly stirring to dissolve the 
 organic residue. When this is completely dissolved, 
 filter, and add filtrate to the previous filtrate a. 
 
 M 
 
178 Clinical Chemistry. [chap. v. 
 
 Concentrate the mixed filtrates to one-fourtli their 
 bulk. The solution contains any mercury that may 
 be present as bichloride. To prove the presence of 
 mercury, (1) place a drop of the solution on a gold or 
 copper coin, and touch with blade of knife ; a bright 
 silvery stain vi^ill appear. (2) Place a few strips of 
 fiire copper-foil in a test-bube, and add a little of the 
 solution, and boil ; the mercury will be deposited on 
 the surface of the copper-foil. Remove the strips and 
 wash them with very dilute solution of ammonia, and 
 dry them between blotting-paper. Then place them at 
 the bottom of a narrow glass tube (German glass), 
 and apply heat ; the mercury will be volatilised, and 
 deposited as a ring of minute globules at the upper 
 end of the tube. The character of these globules 
 can generally be recognised by the eye. If, however, 
 they are too small, remove the strips of copper from the 
 tube, and dissolve the ring by the addition of a drop 
 or so of dilute nitro-muriatic acid, and gently evapo- 
 rate the solution. Dissolve the residue in a little 
 water, and divide into two equal portions ; (a) tested 
 with a drop of dilute solution of potassium iodide, 
 it gives a red precipitate of mercuric iodide, soluble 
 in excess of potassium iodide solution ; (6) a drop 
 added to solution of caustic potash gives a yellow 
 precipitate of hydrated mercuric oxide, insoluble 
 in excess of liquor potassse. (This process is 
 available for the detection of mercury in the solid 
 tissues, care being taken to divide them very finely 
 before treating with hydrochloric acid and potassium 
 chlorate.) 
 
 133. Gastric juice is generally obtained for 
 examination from a gastric fistula in animals, and con- 
 tains saliva, unless the precaution of previously 
 tying the ducts of the salivary glands has been 
 adopted. The following is an approximate analysis 
 of gastric juice obtained from the human subject, and 
 
Chap. V.) Acidity OF Gastiuc Juice. 179 
 
 which, of course, contains a certain amount of saliva : 
 Water, 994-6; Solids, 5-4; i)ei)sin 3-02, free hydro- 
 chloric acid 0'22, alkaline chlorides 2'0, phosphates 
 of lime, magnesia, and iron, 0"15. 
 
 134. Reaction of flic gastric juice is acid, 
 and varies considerably, according to the statements of 
 difierent observers. Thus, Richet, from numerous 
 observations on a patient after gastrotomy, gives the 
 average acidity as 1"7, with a maximum of 3'4 and a 
 minimum of 0'5 per thousand ; Schroder, from obser- 
 vations made in a female with gastric fistula, records 
 it as low as 0*2 ; Schmidt, from experiments on dogs, 
 gives an average of 2 "5, and Szabo, with the same 
 animals, 3* per thousand. These variations need not 
 be considered contradictory, the acidity of the gastric 
 juice no doubt depending much on the nature of the 
 physiological stimulus that excites it. This supposi- 
 tion receives support from the observations of Schmidt, 
 who found the juice of herbivorous animals had a 
 lower degree of acidity than that from carnivorous 
 animals. One point, however, is certain, that the 
 acid is present in a very dilute state, thus confirming 
 the results obtained by experiments with artificial 
 gastric juice, in which a degree of acidity of 0'2 per 
 cent, of hydrochloric acid is found to be most effective. 
 With I'egard to the amount of acid withdrawn from 
 the blood by the gastric secretion during the twenty- 
 four hours, it is impossiljle to speak with any certainty, 
 since the quantity of gastric juice secreted during that 
 period has never been definitely ascertained. Griine- 
 wald, in a case examined by him, states it as t^Venty- 
 three imperial pints, but this was undoubtedly Under 
 Jiatliological conditions. Parkes considers if we put 
 it at twelve pints we shall be within the mark. 
 Lehmann, drawing conclusions from experiments on 
 animals, concludes that the secretion of gastric juice 
 in the twenty-four hours amounts to one-tenth of the 
 
i8o Clinical Chemistry. [Chap. v. 
 
 whole weight of their body. This, per man, would 
 represent something like 14 lbs. avoirdupois. Un- 
 fortunately^ as E,ichet well observes, the data upon 
 which these calculations are founded are very uncer- 
 tain, since it is extremely difficult to determine the 
 relative proportion of the true gastric secretion 
 from the mucus mixed with it, and also to make 
 allowance for what passes off accidentally during 
 the experiment by the pylorus, and what is absorbed 
 by the veins of the stomach. Moreover, even if 
 these obstacles should be overcome, the intermittent 
 nature of the secretion would make it difficult 
 to arrive at very definite conclusions. It has now 
 been incontestably proved that the acidity of the 
 gastric juice is due to free hydrochloric acid. Eichet 
 has shown that in the fresh secretion this is the only 
 mineral acid present. Lactic, acetic, and butyric 
 acids are also met with in gastric juice, the result of 
 fermentative changes occurring in the stomach. In 
 certain morbid conditions they may be considerably 
 in excess of the hydrochloric acid (indeed, that acid 
 may be very scantily secreted), and thus, by causing 
 delay in gastric digestion, lead to the formation of 
 these organic acids. In many cases of acid dyspepsia 
 it is a matter of importance to determine whether 
 the acid in the vomited matters contains a due pro- 
 portion of hydrochloric acid, or whether the organic 
 acids are in excess. In the former case, the acidity 
 will arise from hyper-secretion ; in the latter, from 
 fermentative changes ; or both acids may be in excess. 
 Till recently we had no ready means of determiniiig 
 the nature of the acid present in the vomited matters, 
 and therefore uncertainty frequently existed as to the 
 conditions under which the acids expelled were formed 
 in the stomach. Richet, however, has suggested a 
 method by which the nature of the acid can be 
 accurately determined, and has thus supplied us with 
 
Chap, v.] CO-EF-FICIENT OF PaRTAC.E. i8i 
 
 an additional means of diagnosis in those cases of 
 •stomach diseaso attended with the vomiting of acid 
 matters. His mc^thod is based on the fact tliat if an 
 aiiueous acid sohition be sliaken with ether the latter 
 removes a constant quantity of the acid. This, in 
 the case of mineral acids, is extremely small, but with 
 organic acids the removal is considerable. The specific 
 ratio which exists, after an aqueous solution of acid 
 has been agitated with ether, between the quantity of 
 acid taken up by a certain volume of ether and that 
 which remains in an equal volume of the solution 
 after it has been treated with ether, is called the " co- 
 efficient of partage," a term originally applied by 
 Berthelot. The co-efficient of pai'tage, in the case of 
 mineral acid, is high (above 500) because the 
 quantity of acid yielded to the ether is small ; the co- 
 efficient for the organic acids is low, for the opposite 
 reason. The following example will render the matter 
 clearer : lUO grammes of water containing 11 grammes 
 of lactic acid, and 100 grammes of ether agitated 
 with this solution removes 1 gramme of acid ; so 
 when we determine the acidity of the two fluids we 
 lind that of the water to be 10 and that of the ether 
 1. But supposing the degree of dilution to be ten 
 times gi'eater than in the tirst case, then 100 grammes 
 of water whicli contain 1"1 grammes of lactic acid, 
 agitated with an equal weight of ether, will yield to 
 the ether O'l gramme, and retain 1 gramme, the co- 
 efficient of lactic acid is therefore said to be 10. The 
 co-efficients of many other organic acids have been 
 determined. Some of the most important, as having a 
 bearing on animal chemistry, are succinic acid c'=6, 
 benzoic acid c'=l'8, oxalic acid c'=9'5, acetic acid 
 c'=l'4. So far as concerns one acid in solution the 
 operation is simple enough ; but when we have to deal 
 with a mixture of two or more we must have recourse 
 to a series of agitations with ethei", so that we may 
 
1 82 Clinical Chemistry. [chap. v. 
 
 separate tlie acid which is the most readily soluble in 
 ether from the one that is less so. By such repeated 
 treatment of the original acid solution with ether, and 
 recording the co-efficient of partage after each opera- 
 tion, we are able to obtain the true co-efficient of 
 partage for each acid. E,ichet has found by repeated 
 experiments that gastric juice, when freshly taken 
 from a fistula, has a high co-efficient of partage corre- 
 sponding to that of hydrochloric acid, whilst by 
 keeping the juice some time the co-efficient of partage 
 gradually fell, denoting the increase of the organic 
 acids from fermentative changes taking place in the 
 secretion. Another argument pointing conclusively 
 in favour of the acidity of the gastric juice being due to 
 hydrochloric acid, is that if we estimate the bases and the 
 chlorine separately, we find that there is more chlorine 
 than is required to convert all the bases into chlorides. 
 As Ewald remarks, the excess of chlorine can only 
 exist as free hydrochloric acid, or in an organic 
 combination. In addition to this, the fact that the 
 determined acidity of the gastric juice as obtained 
 experimentally by means of fistulse closely corresponds 
 with the degree of acidity at which the artificial 
 gastric juice is most active (viz., 0*2 per cent, of 
 hydrochloric acid), is another point proving that 
 hydrochloric acid is the acid concerned in gastric 
 digestion, since it has been shown experimentally that 
 when artificial gastric juice is prepared with lactic 
 acid instead of hydrochloric acid, a degree of acidity 
 six times greater than the natural acidity of the 
 gastric juice is required to effect digestion, whilst if 
 acetic acid is employed the degree of acidity required 
 is twice as great. 
 
 We must now proceed to consider the manner in 
 which the hydrochloric acid of the gastric juice is 
 separated in a free state from the alkaline blood. It 
 is only recently that an explanation has been offered 
 
Chap, v.] Acidity OF Gastric Juice. 183 
 
 to account for this seeming paradox. In 1874,* in 
 order to elucidate this point, I made in the lahoratory 
 of the Charing (^i-oss hospital a series of experiments, 
 iu wliich 1 found, liy introducing an alkaline solution 
 consisting of sodium bicarbonate (5 per cent.) and 
 neutral sodium phosphate (5 per cent.) into a small 
 U-tube, fitted witli a diaphragm at the bend, and 
 passed a weak electric current through the solution, 
 that in a short time the lluid in the limb connected 
 with the negative pole increased in alkalinity, whilst 
 the fluid in the limb connected with the positive pole 
 became acid from the formation of acid sodium 
 phosphate. Now, one of the chief salts in the blood 
 is undoubtedly sodium or potassium bicarbonate, an 
 acid salt with an alkaline reaction; and neutral sodium 
 jihosphate has also an alkaline reaction. The decom- 
 position Avhich occurs between them may be repre- 
 sented as follows : 
 
 Acid sodium Neutral sodium Normal sodium Acid sodium 
 
 carbouate. pliospLate. carbonate. phosphate. 
 
 NaH.COa -t- NaoHPO^ = Na.HCO., -f NaHoPO,. 
 
 The above reaction explains the presence of acid 
 sodium phosphate in urine. To account for the 
 formation of free hydrochloric acid in the gasti'ic juice, 
 sodium chloride is substituted for the neutral sodium 
 phosphate, the decomposition in this case being 
 
 Acid sodium 
 ciirbouate. 
 
 Sodium 
 chloride. 
 
 Normal sodium 
 carbonate. 
 
 Hydrochloric 
 acid. 
 
 NaHoCOo - 
 
 t- NaCl = 
 
 = Na.,HCOo 
 
 -1- HCl. 
 
 Maly, however, who subsecpiently investigated 
 (1877) the subject with great care, has come to the 
 conclusion that the hydrochloric acid is derived from 
 
 * Lancet, p. 29, July 4th, 1874. 
 
184 Clinical Chemistry. [Chap. v. 
 
 the decomposition of neutral sodium phosphate with 
 calcium chloride, as described §§ 79 — 84. 
 
 Practi<"ally, it matters little which view we adopt, 
 since all the salts named are present in the blood ; the 
 important fact being, that out of the body a weak 
 electrical current will separate the acid from its base. 
 Whether the decomposition occurring in the body is 
 due to the same agency must for the present remain a 
 matter of conjecture. Whatever be the nature of the 
 agency that causes the decomposition, it must be a 
 powerful one to effect the separation of hydrochloric 
 acid from bases for which it has such a strong affinity 
 as soda or lime. The decomposition, however, once 
 effected in the blood, there is no difficulty in explain- 
 ing the presence of free hydrochloric acid in the 
 stomach, since Graham showed many years ago 
 that this acid possesses high diffusive power, and 
 passes from a mixture through a dialyser with great 
 rapidity. 
 
 135. Pepsin is most conveniently prepared by 
 dissecting off the mucous membrane of the stomach 
 of a recently killed animal, rejecting the pyloric 
 extremity. The mucous membrane is then sliced 
 into thin shreds, and macerated in dilute phosphoric 
 acid till dissolved. The mixture is then strained 
 through coarse muslin, and the filtrate precipitated 
 with an equal volume of lime-water. The precipitate 
 is collected in a filter, well washed, and dissolved in 
 dilute hydrochloric acid. The solution is then placed 
 in a glass flask, and a saturated solution of cholesterin, 
 in one part of ether and four parts of alcohol, is 
 passed down to the bottom of the flask by means of 
 a tube, and the whole mixture well agitated. The 
 cholesterin separates, mingling with the pepsin. The 
 cholesterin is removed by repeated treatment with 
 ether, leaving the pepsin as a greyish- white powder, 
 insoluble in water, alcohol, and ether, but very soluble 
 
Chap, v.] Pepsin. 185 
 
 ill dilute acids. The acid solutions are precipitated 
 liy alcohol, and by ntmtral and basic load acetate, but 
 not by strong nitric acid, tannic acid, or mercuric 
 t'hloride. Pepsin by itsdf has no action on albu- 
 minous substances, but, in conjunction with dilute 
 acid, converts them into peptones. By this conversion 
 albuminous substances become more difTusible. Tlius, 
 taking the dillusion rate of ordinary albumin at 100, 
 we find that, when converted into peptone, the 
 diffusion rate is 7'1 — 9-9; in other words, it is in- 
 creased about twelve times. The natural acid of the 
 gastric juice is, as stated in the pi'eceding para- 
 graph, hydrochloric acid, and the degree of acidity at 
 which digestion is best effected was put at about 
 0'2 per cent, of the real acid. The proportion be- 
 tween the quantity of acid and the quantity of 
 pepsin required to reduce a given amount of albu- 
 minous material may be thus stated. If, during 
 artiticial digestion, the process comes to a stop, the 
 addition of some dilute acid Avill set it going again. 
 After a time, however, the addition of acid is not 
 suflicient, and more pepsin has to be added. The 
 quantity, however, of pepsin required, as compared 
 with the quantity of albumin digested, is really very 
 small. The action of gastric juice on the various 
 food-stuffs can be readily studied by means of a 
 glycerin extract of pig's stomach,* and a 0*2 per 
 cent, solution of HCl. With fats, the gastric juice 
 dissolves the albuminous envelopes of the fat cells, 
 whilst the temperature (40° C.) at which digestion is 
 carried on renders the solid fats fluid, but no real 
 chemical change occurs. Gastric juice has no action on 
 
 * This is made by mincing the mucoiis membrane of a pig's 
 stomach, and covering it with glycerin. After standing fortj'-cight 
 hours, the glycerin is strained off, and more glycerin added to the 
 residue, and tliis again strained off. The process is repeated till 
 all the pepsin has been extracted. 
 
1 86 ' Clinical Chemistry. [Chap. v. 
 
 the starchy matters of the food, but it does not put a 
 stop to the conversion of starch into glucose by the 
 saliva. Gastric juice dissolves (^efc^im/erows tissues; 
 that is, gelatin, after digestion with artificial gastric 
 juice, loses the power of gelatinising. The casein of 
 milk is coagulated before being converted into 
 peptone ; this curdling is apparently caused by some 
 ferment which sets up lactic acid fermentation (Ham- 
 marsten) of the milk sugar, and is not due to the 
 acid of the gastric juice itself. All proteid bodies, 
 with the exception of lardacein, are converted into 
 peptones by the action of pepsin in dilute acid solu- 
 tions. The circumstances chiefly influencing gastric 
 digestion may be thus enumerated : Digestion pro- 
 ceeds best at temperatures between 35° and 40° C. ; 
 boiling destroys all action ; neutralisation, or the 
 presence of too much acid, arrests the action ; the 
 concentration of the products of digestion retard 
 digestion ; minute subdivision, by increasing the 
 surface acted on by the gastric juice, favours 
 digestion ; alcohol, strong alkaline mixtures, and 
 salts of the heavy metals, also interfere with the 
 process. 
 
 135 a. Peptones, as obtained by the action of 
 gastric juice on proteid substances, are white amor- 
 phous bodies, giving an acid reaction to litmus paper, 
 soluble in water. Their solutions are not coagulable 
 by heat, nor by mercuric salts, tannic acid, mineral 
 a^ids, or alkalies. Bile, added to an acid solution of 
 peptone, precipitates it. The reason of this is not 
 clear ; it is probably analogous to the precipitation of 
 parapeptone that occurs on neutralisation with sodium 
 carbonate. When quite pure, i.e., free from un- 
 digested albumin, they should give no reaction with 
 Millon's test or the xantho-proteic reaction. Mixed 
 with Fehling's solution, they give a purple-violet ; 
 but, when floated on the surface, the coloration at 
 
Chap. V.) Peptones. 187 
 
 tlic junction of the two fluids is rosy red. According 
 to Dr. Guoi-ge Jolinson, thoy are precipitated l>y 
 picric acid, tlie precipitate being re-dissolved when 
 heated. This last reaction, in my opinion, is due to 
 the presence of a bye-product, parapeptone or hemi- 
 albuniose, rather tlian characteristic of the true 
 ])eptone. Tlie peptones all possess Isevo-rotatory 
 power. There are several varieties of peptones. 
 According to the original view of Meissner, there 
 is a bye -product resembling syntonin, which he 
 called parapeptone ; intermediate products, called 
 metapeptone and A and B peptones ; and tlie true, or 
 C, peptone.. Kiihne considers that the initial step in 
 botli gastric and pancreatic digestion is the breaking 
 up of albumin into anti-albui)iose and Jiemi-albumose. 
 The former is converted into anti-peptone, which 
 undergoes no further change, either by the action of 
 gastric or pancreatic digestion, and gives the reactions 
 above described as characteristic of true peptone ; the 
 latter is converted into hemi-peptone, which, by the 
 action of trypsin, the pancreatic ferment, is converted 
 into leucin and tyrosin, and to which we shall refer 
 when speaking of the pancreatic juice. With regard to 
 the two bye-products, anii-albumose and hemi-albumose, 
 the former may be regarded as identical with Meiss- 
 ner's parapeptone, and the latter with, his a peptone. 
 With regard to their charactei'S, anti-albumose, or 
 parapeptone, is insoluble in water, soluble in dilute 
 acids ; and the acid solution is precipitated by potas- 
 sium ferrocyanide, mercuric chloride, tannic acid, and 
 picric acid. Hemi-albumose, or IMeissner's A peptone, 
 is soluble in water at 70° C, but is re-precipitated on 
 cooling, soluble in 10 per cent, solutions of sodium 
 chloride ; it thus resembles the " albumin " found in 
 the urine of a case of osteo-malacia by Dr. Bence 
 Jones. With regard to the composition of these 
 bodies, they are generally regardetl as hydrates of 
 
1 88 Clinical Chemistry. [Chap. v. 
 
 albuminate^ and are formed by albumin taking up 
 water, as starcb does to form glucose. Henninger is 
 said to have proved this by changing peptone back 
 to syntonin by the abstraction of water. The clinical 
 interest attacliing to the peptones is their appearance 
 in urine under various morbid conditions. The 
 method for isolating these bodies is described § 118, 
 page 148. 
 
 136. Vomited matters. — Vomiting is induced 
 («) directly, by stimulation of the stomach ; (h) indi- 
 rectly, through the irritation of other arid distant 
 organs. In the first category we have to consider the 
 vomiting in relation to disease of the organ, cancer, 
 ulceration, stricture of the pylorus, or poisoning by 
 corrosive poisons, etc. ; and here we have to determine 
 the conditions with regard to the digestion of the 
 food ingested, the acidity of the gastric secretion, the 
 presence or absence of blood or bile, cancer cells, and 
 sarcinse. In the second category, viz., vomiting pro- 
 duced by irritation of distant parts, the retching 
 produced by tickling the fauces is the most familiar ; 
 but reflex vomiting may be produced by irritation of 
 any organ ; thus, the vomiting in uterine disease on 
 the passage of renal or biliary calculi ; the early 
 vomiting of phthisis and in disease of the brain ; or 
 it maybe caused through the nervous system by toxic 
 agents, as tobacco, lobelia, opium, etc. ; or by blood 
 poisons, as in erysipelas, septicsemia, gout, etc. For 
 clinical purposes, the chemical examination of vomited 
 matters may be limited (1) to an inquiry into the 
 nature of acid present, whether due to hyper- secretion 
 of gastric juice (excess of hydrochloric acid), or from 
 fermentative changes occurring in the stomach (excess 
 of lactic or acetic acid) ; (2) the detection of poisonous 
 substances in the vomit. 
 
 (1) Determining amount and nature of acid 
 present in vomit. — In directing our treatment with 
 
Chap, v.] Vo.i//r. 189 
 
 regard to stomach afTeotions it is of the utmost im- 
 j)ortHnce for us to recognise whether the acid present 
 in the vomited matter is due to hyper-secretion of 
 gastric juice (hydrochloric acid) or to fermentative 
 changes, lactic acid, etc.* Nor is it sufficient to 
 rest content with one examination only, since in 
 these cases it often happens that both forms may be 
 present, but that one preponderates more at one 
 time than another. Thus, Dr. Gokling Bird states 
 that in a case of scirrhous pylorus he found at 
 one time a quantity of free hytlrochloric acid in one 
 pint of vomit equal to twenty-two grains of the 
 pharmaceutical acid, with an organic acid sufficient in 
 quantity to neutralise seven grains of pure potash. 
 At another time the hydrochloric acid had nearly 
 disappeared, and the quantity of organic acid in each 
 pint required for saturation nearly seventeen grains 
 of the alkali. If, therefore, we ai-e desirous of giving 
 relief we ought to follow regularly the variations 
 in the character of the acid in the vomited matters. 
 For this purpose the following plan of procedure will 
 be found easy as well as i-eliable. The vomit is 
 poured into a tall cylindrical glass jar, aiid allowed to 
 settle. Of the supernatant fluid draw off 100 cc, or if 
 so much cannot be obtained, then 50 cc. or 25 cc. 
 Shake this up with an equal weight of ether in a 
 cylindrical tube, set aside till the ether has separated 
 from the mixture. Then remove etherial solution by 
 means of a pipette. Now, as it has been stated 
 (§ 1.34, page 181), that the organic acids are more 
 readily removable by ether than the mineral acids, so 
 that the acidity of the etherial solution represents in 
 the main the acidity due to organic acids, whilst the 
 
 * I have endeavoured to discriminate between the forms of 
 " acidity " met with in functional disorders of tlie stomach by 
 reference to the condition of the urine. (Sec chaps, ii. and iii., 
 " Morbid Conditions of the Urine." Churchill, 18S2.) 
 
I go Clinical Chemistry. [Chap. v. 
 
 acidity of the vomit, after extraction by ether, repre- 
 sents nearly the whole of the mineral acids (hydro- 
 chloric). If, therefore, we take the acidity of the 
 supernatant fluid of the vomit before agitation with 
 ether, by the same process as directed for determining 
 the acidity of urine (§ 107, page 112), and again after- 
 wards, we can judge by the difference in the acidity 
 whether the organic or mineral acid is in excess. 
 If the former, the rediiction in the acidity will be 
 marked ; if the latter, it will not be considerable. If 
 we desire to find out what organic acids are present, 
 the vomit will have to be treated repeatedly and suc- 
 cessively with ether till the co-efficient of partage of 
 each has been determined. There is no necessity, how- 
 ever, for engaging on this lengthy process ; for clinical 
 purposes it is sufficient to determine whether we are 
 dealing in any given case with excess of organic or 
 mineral (hydrochloric) acid. 
 
 (2) Detection of poisons in 'tiomit. — Without 
 engaging in the elaborate and exact processes of 
 analysis requisite for toxicological purposes, and 
 whichj when required for medico-legal purposes, should 
 always be conducted by a professional expert, medical 
 men frequently have to decide, when called to a case 
 of urgent vomiting, whether it is due to a poisonous 
 agent. In these cases there is generally no time to 
 refer the matter to an analytical chemist. Every 
 medical man, therefore, ought to be able to conduct a 
 preliminary enquiry, so as to gain some insight as to 
 the nature of the case with which he is dealing. As 
 a rule a clue is afibrded by the chai'acter of the 
 symptoms, which show whether the poison belongs to 
 the irritant class, or is a corrosive substance, or one of 
 the vegeto-alkaloids ; and we have generally some of 
 the substance taken left, which also inaterially assists ; 
 thus we readily recognise oil of almonds, vermin paste, 
 oil of vitriol, oxalic acid, and the like. But where the 
 
Chap, v.] Vomit. 191 
 
 substance cannot be obtained for inspection, ami the 
 symptoms are obscure, we are forced to make an 
 elementary analysis. The plan to be adopted is as 
 follows: — Reserve a sufficient portion of the vomit for 
 detailed examination at the hands of an expert ; place 
 this in a strong bottle tightly corked and sealed. With 
 regard to the surplus proceed according to the follow- 
 ing method, which deals with the most common forms 
 of poisoning. 
 
 (a) Volatile poisons. — Place a small quantity of 
 the fluid in a test tube, and gently warm the fluid ; if 
 prussic acid is present, the peculiar odour Avill be 
 evolved. The best confirmatory test for this is to 
 l")lace a little of the vomit on a small watch-glass 
 or glass slide, and add, by means of a stirring-rod, 
 five or six drops of strong sulphuric acid ; hold 
 over the watch-glass another moistened with liquor 
 potasste. The fumes of the hydrocyanic acid form 
 potassium cyanide. This is tested by stirring it 
 with a rod dipped successively in a solution of a 
 ferrous salt, ferric salt, and hydrochloric acid, when, 
 if hydrocyaniG acid is present, Prussian blue will 
 be developed. If no hydrocyanic acid be found, 
 apply strong heat to another portion of the vomit 
 placed in a narrow tube, and cany the tube into 
 a darkened room to see if fumes of 'phosphonus are 
 given off". 
 
 (6) (Jorroslve poisons. — Test with litmus paper; if 
 strongly acid, probably oxalic acid (§ 47), sulphuric acid 
 (§ 82), hydrochloric acid (§ 79), or carbolic acid (§ 50) ; 
 if strongly alkaline, due to some of the caustic alkalies 
 or alkaline salts. 
 
 (c) Metallic irritant poisons. — Some of the vomit, 
 acidulated with pure hydrochloric acid, is placed in a 
 test-tube, and a strip of perfectly clean copper, dijjped 
 in alcohol to prevent fatty matters adhering to it, is 
 then immersed in the acidulated mixture, and heat 
 
192 Clinical Chemistry. [Chap. v. 
 
 applied for about twenty minutes. If arsenic, anti- 
 mony, or mercury is present, the copper will be 
 stained black. Remove the copper strip, and wash it 
 with a little very dilute solution of ammonia, and 
 then dry it between folds of blotting-paper. Then 
 place in a narrow glass tube, and proceed as directed 
 for the detection of mercury (§ 132), arsenic and 
 antimony (§ 151). 
 
 Strychnine and morphia. — A small portion of the 
 vomit is to be rendered strongly alkaline with sodium 
 carbonate, and agitated with four times its volume of 
 ether. After the etherial solution has formed a layer 
 on the surface, it is to be removed by means of a 
 pipette, and allowed to evaporate spontaneously in a 
 watch-glass ; the residue is to be examined for mor- 
 phia (§ 70), strychnia (§ 71). It is often sufficient 
 to place a drop of the etherial solution on the tongue, 
 by means of a glass rod, to learn the character of 
 the alkaloid. If a frog can be obtained, evidence 
 of poisoning by an alkaloid is then most readily 
 obtained by injecting some of the ether extract under 
 the skin. 
 
 Opium. — Evaporate a small portion of the vomit 
 on a porcelain dish ; touch the dry residue with ferric 
 chloride ; a cherry -red colour, which does not disappear 
 when touched with mercuric chloride, indicates the 
 presence of meconic acid (§ 83). 
 
 137. Oases in the stoKBiach< — -The nature of 
 the gaseous contents of the stomach in health and 
 disease will be best considered with reference to the 
 gases in the intestinal canal (§ 150). 
 
 138. Bile. — The composition of the bile varies 
 considerably, the proportion of its solid constituents 
 ranging from 9 to 17 per cent., being always most 
 after a meal. The following analyses, (1) made by 
 Frerichs, is from the bile taken from the gall-bladder 
 of a healthy man killed by an injury; (2) the mean of 
 
Chap, v.] 
 
 Composition of Bile. 
 
 193 
 
 five analyses by Hoppe Seyler, obtained from bodies 
 in the post-mortem room : — 
 
 
 No. 1. 
 
 No. 2. 
 
 
 Frcrichs. 
 
 Hopije Seyler. 
 
 Water 
 
 Inorganic salts .... 
 
 85-92 
 •78 
 
 91-68 j 
 
 Organic matter .... 
 
 13-30 
 
 8-32 
 
 ^lucus pigment .... 
 
 2-98 
 
 1-29 
 
 Bile salts 
 
 9-14 
 
 3-90 
 
 Fat 
 
 •92 
 
 0-73 
 
 Soaps "1 
 
 
 ( 1-39 
 
 Cholesterin I . . . . 
 
 •26 
 
 { 0-35 
 
 Lecithin J 
 
 
 (0-53 
 
 Obtained fresh, as it flows from the liver, it is a 
 thin, transparent fluid, of golden-yellow colour, like 
 yolk of egg, of a very bitter taste, of alkaline re- 
 action, and an average sp. gr. of 1-018. When 
 obtained after death, the colour is of brownish- 
 yellow ; it acquires a tenacious consistence from the 
 presence of mucin, which is furnished by the gall- 
 ducts and gall-bladder. Bile mixes freely with oil 
 and fat, and, when shaken with them, forms an 
 emulsion, which renders their passage through animal 
 membranes more easy. Added to a solution of gastric 
 peptones, a precipitate occurs ; this precipitate is 
 caused, no doubt, by the alkaline salts of the bile 
 precipitating the parapeptone from its acid solution. 
 The quantity of bile secreted increases suddenly after 
 a meal, reaches its maximum in about two hours, and 
 then gradually declines. The quantity of bile dis- 
 charged daily may be put at forty ounces. Thus, 
 Carpenter, from the experiments of Nasse, Plainer, 
 and Stackman, calculated that a man weighing 154- 
 pounds should secrete this quantity ; whilst jNIurchison 
 
 N 
 
194 Clinical Chemistry. [Chap. v. 
 
 records (Case CLXxii., Diseases of Liver) an instance 
 where quite two pints of bile were discharged daily 
 through a fistulous opening in the gall-bladder. Of 
 ' this quantity, only a small portion escapes by the 
 bowel, the remainder being re-absorbed in the intes- 
 tines. Thus, the experiments of Bidder and Schmidt 
 on dogs have shown that only j^^th of the sulphur 
 originally passed into tbe intestine with the bile 
 appears in tlie faeces. Bischoff, again, has calculated 
 that about 46 grms. of the altered biliary acids are 
 discharged by man daily with his faeces, whilst Voit 
 has shown that the average daily quantity formed by 
 the liver amounts to 170 grms. ; therefore 124 grms. 
 must be otherwise disposed of. The observations of 
 Jalfe and McMunn have shown that the bilirubin of 
 the bile pigment is oxydised in the intestine to uro- 
 bilin, in which condition it is absorbed, and passes off 
 from the body by the kidneys as the chief colouring 
 matter of the urine, either as urobilin or its more 
 oxydised product choletelin, only a portion of the 
 biliary pigment being discharged by the intestines 
 with the fajces. As Murchison pointed out, this 
 re-absorption of bile is, in fact, merely part of that 
 chemical circulation which is constantly taking place 
 between the fluid contents of the bowel and the blood, 
 the existence of which has been already alluded to 
 (§ 9). Bile has no action upon the digestion of pro- 
 teid substances, beyond the negative effect of preci- 
 pitating paraptjptone, as noticed above. The bile 
 oi some animals has an action on starch, converting it 
 into glucose ; and some observers state that, to a 
 slight extent, a similar action occurs with quite 
 fresh human bile. It acts, however, on the fatty 
 substances by forming an emulsion with them ; this 
 can be seen by placing a drop of cod-liver oil on a 
 glass slide, and adding a drop of fresh bile, when a 
 milky emulsion will be formed. Owing to the alkaline 
 
Ch;.|). v.] Jaundice. 195 
 
 salts, bilo is capable of forming soaps with fatty 
 acids. Experimentally it has been shown, after ap- 
 plying a ligature to the common duct, that an 
 animal absorbed less fat than before. It has also 
 been pointed out that, where biliary fistulse have been 
 established for a consideral)le time, nutrition was 
 only kept up so long as the loss was compensated by 
 increased food. Bile acts as a natural purgative, by 
 Ktimulating peristalsis ; and, since it possesses powerful 
 antiseptic properties, it arrests putrefactive fermenta- 
 tion in the intestines. A defective secretion of bile, 
 therefore, is one of the chief causes of flatulent 
 dyspepsia. In my work on " Morbid Conditions of 
 the Urine associated with Derangements of Diges- 
 tion " (p. 49), 1 have pointed out that the form of 
 dys])cpsia ai'ising from deficient secretion of bile is 
 frequently attended with an alkaline condition of 
 urine, since the bile, being the chief secretion by 
 which the alkaline salts are discharged from the 
 blood, any hindrance, therefore, to the discharge of 
 the bile leads to their being eliminated in greater 
 quantity by the kidney. It is in this form of 
 dyspepsia that the greatest good is obtained by tlie 
 administration of dilute hydrochloric acid. Dr. Wick- 
 ham Legg is of opinion that the passage of bile into 
 the intestine appears in some way necessary to the 
 formation of glycogen by the liver, since, after liga- 
 ture of the bile-duct of a cat, the diabetic puncture 
 failed to give rise to sugar in the urine. In jaundice, 
 a yellow tingeing of the skin, as well as the other 
 tissues and fluids, takes place, owing to the presence 
 of biliary matters in the circulation. Jaundice is gene- 
 rally considered as being either iLeptof/enous, caused 
 l)y re-absorption of bile either fi'om obsti'uction of the 
 bile-ducts or from disturbances of the portal cii'cu- 
 lation, and hcematoyenous, from changes occurring in 
 the blood. Among the causes leading to heptoyenous 
 
196 Clinical Chemistry. [Chap. v. 
 
 jaundice are, (1) simple catarrh of the bile -ducts, 
 either by a mucus plug in the gall duct or by swelling 
 of the mucous fold over the orifice of the duodenum, 
 accompanied with gastro-intestinal catarrh, as is seen 
 in malarial fever, secondary syphilis, pyaemia, etc. ; 
 (2) direct obstruction of the ducts, as by impaction of 
 gall stones or the presence of tumours ; (S) sudden 
 changes of blood pressure, as haemorrhage from the roots 
 of portal veins, which favours the imbibition into the 
 circulation of the secreted bile. The icterus menstrualis, 
 and the jaundice so often observed in pneumonia of 
 the right lung, are probably caused by the alteration 
 of the blood pressure in the portal system. 
 
 IIce.matogenous jaundice is accounted for : (a) That 
 when the destruction of liver tissue is extensive, the 
 pigments of the bile are formed in the blood, (h) That 
 the bile pigment in these cases is obtained by the disso- 
 lution of the blood corpuscles, and by the conversion 
 of the haemoglobin into bile pigment. Among the 
 forms of jaundice, of haematogenous origin, are the 
 jaundice of acute yellow atrophy, phosphorus poisoning, 
 typhus, pyaemia, and septicaemia, and the jaundice fol- 
 lowing the bites of venomous animals. With regard to 
 the theories supported in advance of a true haemato- 
 genous jaundice, it will be sufficient to say, with regard 
 to the view that jaundice arises when the liver is exten- 
 sively destroyed, by the accumulation of the bile pig- 
 ment in the blood, that physiology has long since dis- 
 posed of the view that the biliary elements are pre- 
 formed in the blood ; they are only elaborated by the 
 liver. With respect to the statement that the jaundice 
 in these cases is due to dissolution of the blood cor- 
 puscles and the conversion of the haemoglobin into bile 
 pigments, experiment has sho'^n that a variety of 
 different substances, possessing quite a diverse character, 
 introduced into the circulation, such as water, bile 
 acids J ether, chloroform, etc., have the power of causing 
 
ch.ip. v.] Jaundice. 197 
 
 bile pigment to appear in tlic uriiiP ; but that is quite 
 a din'eront matter to converting liivnioglobin into bile 
 ])ignu'nt in tlio circulatic^n witlioiit the intervention of 
 the liver. If dissolution of the blood corpuscles, and 
 the conversion of the ha'niof,dobin into bile pi^nnent 
 was, as the propounders of this theor.y maintain, the 
 cause of ha>matogenous jaundice, then scurvy, in which 
 the dissolution of the blood coipuscles is carried to 
 a great extent, would be invariably associated with 
 jaundice, which, however, is rarely the case. In that 
 obscure disease ha^matinnria (§ 120, page 161), where 
 the colouring matter of the blood appears in the urine 
 freed from the corpuscles, jaundice, though generally 
 present, is only slight, certainly not what would be 
 expected with such extensive destruction of blood 
 corpuscles. Indeed, it is j^robable that hajniatinuria 
 depends rather on some functional disturbance of the 
 liver, by which the effete haemoglobin is not re- 
 duced to luematiii, and froju ha-matin to bilirubin, 
 as a failure of a normal process, than from any 
 positive evidence that the dissolution of the l;lood 
 corpuscles is caused by the introduction of a toxic 
 agent into the blood. Moreover, in addition to the 
 objections above urged to the existence of an ha?ma- 
 togenous jaundice, the oj)inion is gaining ground that 
 in the cases where it is said to occur there exists some 
 overlooked catarrh in the capillary system of gall ducts, 
 and so that the jaundice is really lieptogenous. The 
 microscopic examination of the livers of dogs poisoned 
 with phosphorus has shown incontestably that the finer 
 ducts were plugged with a colourless mucus ; and when 
 we reflect how readily the bile has been shown, experi- 
 mentally, to pass into the circulation on the slightest 
 increase of excretory pressure, we can conceive how a 
 very slight exudation in the liner tubes may cause very 
 appreciable jaundice, although the obstruction of the 
 tubes may not be visible to the naked eye. Lastly, the 
 
198 Clinical Chemistry, [Chap. v. 
 
 supporters of tlie hsematogenous theoiy have long- held 
 the view that in these cases the bile acids are not 
 found in the urine, yet in the jaundice associated with 
 pyaemia and septicaemia, which is one of their strongest 
 instances of a jaundice arising from blood poisoning, 
 the presence of, the biliary acids in the urine has been 
 repeatedly demonstrated. The position I would take 
 with regard to the existence of a hsematogenous 
 jaundice is this, that there is a form of jaundice arising 
 from a primary morbid condition of the blood, which 
 leads to catarrh of the finer hepatic ducts, and so 
 causes jaundice from re-absorption of bile already 
 formed by the liver cells, and that the jaundice is not 
 occasioned by the conversion of haemoglobin into bile 
 pigment in the circulation. With this proviso it 
 is convenient to retain the term haematogenons as 
 distinguishing between the forms of jaundice arising 
 from primary changes, occurring in the condition of 
 the blood, leading to catarrh of the finer biliaiy ducts, 
 as apart from the jaundice arising directly (hepto- 
 genous) from obstruction. 
 
 The analysis of bile is conducted as follows. The 
 specific gravity is taken by means of the specific 
 gravity bottle (§ 92), and the degree of alkalinity of 
 the secretion by the process, and with the same 
 standard solution as described in determining the 
 alkalinity of blood (§ 93). 
 
 139. The miicin is then to be removed by pre- 
 cipitation with alcohol or acetic acid. On the addition 
 of either of these to bile, stringy ropes of mucin are 
 formed. These must be allowed to subside, and the bile 
 thus clarified decanted oflT and passed through a fine 
 muslin filter. This is divided into two portions {a) 
 evaporated at a gentle heat to one-fourth its bulk. 
 This forms inspissated bile extract, (b) Evaporated to 
 half its bulk, mixed with an equal quantity of animal 
 charcoal, and introduced into a flask containing twice 
 
Chnp. v.] Bile Pigments. 199 
 
 its bulk of alcohol, it is digostod till wanted. This 
 furnis alcoItoJic bile extract. Tlu- stiiiifjy ropes of mucin 
 are then collected in a flask, and shaken up Avith other 
 to free them from fatty matters, and afterwards washed 
 ■with water. When quite pure from adherinc; impuri- 
 ties, dissolve in a sulHciency of lime or baryta water, 
 filter several times through animal charcoal to remove 
 any colouring; matter of the bile. Tests for mucin, 
 §26. 
 
 140. Bile pijfmoiifs are obtained for examina- 
 tion from the inspissated bile extract or from gall 
 stones. The chief pigment, hilimhin, can be obtained 
 from either of the above-named by extracting succes- 
 sively with water, alcohol, dilute hydrochloric acid, 
 boiling alcohol, and ether. Then boil the dry residue 
 with pure chloroform, and distil the chloroform extract 
 to near dryness, and then add seA^eral volumes of 
 absolute alcohol ; set aside for twenty-four hours, when 
 an orange-red powder mixed with a few bluish-brown 
 crystals will deposit. Bilirubin is insoluble in water 
 and ether, slightly soluble in alcohol, but soluble in 
 chloroform, turpentine, and benzol. On the addition 
 of alkalies to a chloroformic solution of bilirubin it 
 lo-ses its orange-red colour. On passing a current of air 
 through an alkaline solution of bilirubin, hiliverdin 
 is formed, which is deposited in green flocks on the 
 addition of hydrochloi'ic acid. BUifuscin is another 
 pigment, which can be obtained directly from the bile 
 by evaporating a chloroform solution to dryness, dis- 
 solving the residue in alcohol, again evaporating, and 
 shaking up the residue with ether and chloroform, 
 separating the insoluble portion by filtration, and dis- 
 solving it in absolute alcohol, from which bilifuscin 
 is precipitated in brown flocks on the addition of 
 hydrochloric acid. These flocks are soluble in alcohol 
 and alkalies, but insoluble in water, ether, and chloro- 
 form. According to Stiideler, both biliverdin and 
 
200 Clinical Chemistry. [Chap. v. 
 
 bilifuscin are formed from bilirubin by the assump- 
 tion of water, thus : 
 
 Bilirubin. Biliverdin. 
 
 C,eHi3N,03 + H,0 + 0= CieH^N.Og 
 
 Bilii-ubin. Bilifuscin, 
 
 Although none of the bile pigments mentioned above 
 give any spectrum, there are other colouring matters 
 got from bile by treatment with stronger reagents than 
 those required for the separation of bilirubin, bili- 
 verdin, and bilifuscin. Thus, by passing nitrous 
 vapours into an alcoholic solution of bilirubin a final 
 product of oxydation is obtained, which has been 
 named clioletelin.* By pouring the alcoholic solution 
 into water after being thus treated, nearly all the 
 colouring matter separates in the form of flakes, which 
 dry up to a brown powder, which is soluble in alcohol, 
 ether, and chloroform. It gives no play of colour with 
 nitric acid, but it yields a constant spectrum, which, in 
 an acid solution, gives one broad band, extending from 
 6 to a little beyond p. In alkaline solutions the band 
 is less ref rangilole. Jafie also isolated a pigment, which 
 gives the band at F, to which he gave the name of 
 urobilin. E. Maly [Ann. Chem. Pliarm., clxi. 368, 
 clxiii. 77), by dissolving bilirubin in dilute soda or 
 potash ley, and adding sodium amalgam, the air being 
 excluded, no hydrogen was given off, but the dark 
 colour gradually lightened, and after two or three 
 days' action the solution acquired a yellow or bright 
 yellow colour, and then gave off hydrogen. From 
 this liquid, hydrochloric acid separated a pigment, 
 which gave a spectrum identical with that of Jaffe's 
 
 * In the following I have adopted MacMunn's account of this 
 intricate and still obsctire subject. " The Spectroscope in Medi- 
 cine," p. 151. ChurchiU. 1880. 
 
Chap. V.) Bile Pigments. 201 
 
 urobilin. Recent investigations seem to point to the 
 conclusion that cholctelin is the final oxydation product 
 of bilirulnn, and that urobilin is an intermediate stage ; 
 and that while urobilin may appear in the urine, still, 
 under normal circumstances, the ])igment that appears 
 in the urine is cholctelin, though it may be absent in 
 disease. In addition to urobilin or choletelin, Stokvis 
 {N. Rep. Pluirm., xxi, 123) has described another 
 reducible product of the oxydation of bile pigment, 
 which is formed as a secondary product, in most cases, 
 of the oxydation of biliary colouring matter, whereby 
 Gmelin's reaction is produced (§ 120). It is colour- 
 less, or of a light yellow tint, soluble in water, alcohol, 
 and dilute acids. It differs from the bile colouring 
 matter, and other oxydation products, in being insoluble 
 in ether and chloi'oform, and not forming insoluble 
 compounds with neutral or basic lead acetate. When 
 boiled with reducing agents in alkaline solutions this 
 pigment yields a beautiful rose red, wdiich gives in the 
 spectrum a broad band in gi'een. In thick strata the 
 band begins close to d and extends to 6 ; in thin strata 
 or dilute solutions it occupies only two-thirds of the 
 ' distance between D and E, ending short of E. This 
 pigment does not exist in fresh bile, and it is not found 
 in healthy urine. MacMunn thinks that the appearance 
 of the band of this pigment in the spectrum of the 
 urine indicates grave disturbance of the system, as it 
 appears only in those cases where there is undoubted 
 disease of a severe character. With regard to the 
 connection between the colouring matters of the blood, 
 bile, and urine, it is now generally held that the effete 
 hsemoglobin is reduced in the liver to hiematin and bili- 
 rubin, that a portion of the latter is passed out of the 
 body with the fseces, but that another portion is con- 
 verted into urobilin in the small intestine, and is 
 reabsorbed, and by further oxydation is converted into 
 choletelin. The view that hcematoidin and bilirubin 
 
202 Clinical Chemistr y. [Chap. v. 
 
 are identical is still open to qtiestion. tliongli I think 
 , tlie balance of e^"idenee at present rather inclines to it. 
 To demonstrate the presence of bile pigment in any of 
 the secretions recourse is had to Gnielin's reaction. This 
 consists in slowlv mixing (^§ li!0) a few drops of nitric 
 acid, containing traces of nitrons acid, "with the stis- 
 pected fluid, vrhen a play of colours Trill be observed, 
 of -which green is alone characteristic of the bile 
 piigment. If Tve examine this reaction by means of 
 the spectroscope, "sve find the solution gives a broad 
 shading in orange and yelloTv, and a broad band at F. 
 As the osydation proceeds, the shading in orange and 
 yello-w clears up, leavins; only the band in F, the 
 spectrum of urobilin. 
 
 111. Bile acid$. — The method for obtaining the 
 bile acids from urine has been described § lilO. To 
 obtain them from bile "we add excess of alcohol to the 
 alcoholic extract of bile, and filter. The precipitate is 
 dissolved in •w-ater. and the aqueous solution precipi- 
 tated -with neutral lead acetate. The precipitate is 
 removed, -washed, dissolved in alcohol, and the lead 
 removed by precipitation -w-ith sulphydric acid. The 
 clear filtrate on standing -will deposit crystals of* 
 gJycochoUc acid (§ 53). The mother liquor left after 
 the removal of glycochoKc acid is precipitated -with basic 
 lead acetate, and the precipitate treated in the same 
 ■way as directed for glycocholic acid, -when taurocholic 
 acid -will separate out as oily resinous drops (§ 54). 
 Both bile acids give a purple reaction (Pettenkofter's 
 test) -when mixed -with strong sulphuric acid and 
 glucose. The best method of carrying otit the test 
 is described § 120. The spectrum of Pettenkofier's 
 test, according to ]\IacMunn, gives a band outside D, 
 and broad band at e. Heynsius and Campbell, ho-w- 
 ever, give the spectrum of sodium taurocholate -with 
 sulphtiric acid and sttgar, as represented by three bands, 
 one bet-ween c and D, the next bet-«"een D and E, 
 
Chap. V.) Bile Acids. 203 
 
 and the thii-d near F (Pfls^er's Archxv. f. Pht/s., iv., 
 407). Tlio bile acids ai'e furnished by the nietaWlism 
 of the albuminous constituents ; but whether directly 
 from tlie s^»litting up of the pej)tones, as Dr. Wiekhain 
 Legg considei^s probable, seeing the great dependence 
 of the bile-making functions on the glycogenetic func- 
 tion ; or, as seems to me more likely, from the breaking 
 up of the ertete albuminous matters of the body in the 
 liver, is doubtful A portion of the bile acids (chietly 
 the taurochloric acid) passes off by the bowels with the 
 fivces, jvirtly unaltered, partly broken up into taurin, 
 cholic acid, and dyslysin. A portion, chietly the glyco- 
 cholic acid, is absorbed by the intestine. An experi- 
 ment of Tappeiner ( Wiener Sitzgsber, Bd. cxxA-ii. 
 187S, iii. abth) has shown that this absorption oecure 
 in the jejunum and ileum, and not in the duodenum. 
 Of the portion thus absorbed the ultimate fate is 
 unknown. A trace probably passes off with the urine 
 even in health, since Xaunyn and Draggendorf have 
 proved the presence of bile acids in non-jaundiced 
 urine, whilst some portion of the taurocohlic acid is 
 probably oxydised, and furnishes the partially oxydised 
 sulphur product originally observed in the urine by 
 Ronalds, and which, in minute quantities, is always 
 pi-esent in nonnal urine (§ 114). Injection of the bile 
 acids into the blood produces very detinite results. It 
 destroys the red blood-coi-puscles ; if a few drops of 
 solution of bile acids are placed on a glass slide, and a 
 drop of blood be added, no trace of blood corpuscles 
 will be found on microscopic examination. Taurocholic 
 acid seems to possess this property in even a higher 
 degree than glycocholic acid. Bile acids, when injected, 
 cause rapid parenchymatous degenei-ation of the glands 
 and muscles. Their action on the heart is very marked, 
 causing slowing of the pulse. This phenomenon. 
 Dr. ^Viokham Legg (Proc. Poi/al Soc., vol. xxiv., p. 
 •i-42 ; 1S7G) thinks is not due to any influence tlirough 
 
204 Clinical Chemistry. [Chap. v. 
 
 the vagi, or direct action on the muscular walls, but 
 by their influence on the ganglia of the heart. Steiner 
 has confirmed Dr; Legg's view ; but he thinks that bile 
 acts upon only one of the cardiac ganglia, since he found 
 that by letting a drop of bile fall upon the back of a 
 frog's heart there was at once a cessation of the heart's 
 beat, whilst if it was placed on the fore surface of the 
 heart no change in the pulse took place for some time. 
 Injection of bile acids also produces a peculiar spasm 
 of the respiratory muscles, and the diaphragm remains 
 in a state of deep inspiration. They are said to lower 
 the bodily temperature. The urine after injection of 
 bile acids becomes dark-coloured, often with traces of 
 albumin, casts, and granules, but no blood corpuscles. 
 Frerichs considered the dark colour due to the con- 
 version of the bile acids into bile pigment. Kiihne 
 attributes it to the destruction of the blood corpuscles 
 by the bile acids acting on the haemoglobin ; but Dr. 
 Wickham Legg has been unable to satisfy himself of 
 the presence of pigment, in many observations on 
 rabbits, and is inclined to believe the difference iu 
 observation depends on the animal experimented on, 
 since dog's urine often gives the reaction (Gmelin's) 
 for bile pigment, even when the animals are supposed 
 to be in perfect health. Many physicians have been 
 led to regard the presence or absence of bile acids as a 
 diagnostic point, deciding whether the jaundice was 
 heptogenous or hsematogenous in character. In the 
 former, it was said they were present, in the latter 
 absent. No such definite conclusion, however, is war- 
 ranted from the facts before us. Traces of bile acids 
 are to be found in normal urines ; the amount is 
 increased in all forms of jaundice, especially at their 
 onset. In cases due to obstruction, without great 
 destruction of liver tissue, they are often, especially at 
 first, considerably increased, gradually declining in 
 amount as the case goes on, till they often cease to 
 
Chnp. V.) Fattv Matters of Bile. 205 
 
 appear. In jaundice, with destruction of the liver 
 tissue, as in acute yellow atrophy, hepatic abscess, 
 rapidly growing cancer, they are present at first, but 
 as the liver tissue becomes destroyed they disappear. 
 Their presence or absence, therefore, does not dis- 
 tinguish between the nature of the jaundice, but only 
 shows the stage which it has reached. 
 
 142. Fats which consist of cholesteiin, saponi- 
 fiable fats, and lecithin are to be separated and deter- 
 mined as directed for blood (§ 99). With regard to 
 cholesterin, the chief fatty constituent of the bile, it 
 is doubtful whether it should be regarded as formed in 
 the liver, or is merely excreted from the blood. The 
 latter view has been generally adopted, partly in con- 
 sequence of Dr. Flint's views with regard to the 
 supposed toxic influence this body has when its 
 excretion is obstructed, giving rise to a condition he 
 calls cholesteraemia. The reasons against accepting 
 his views have been enumerated when considering the 
 toxic conditions of the blood (§102). I am disposed 
 to think that cholesterin is formed in the liver as well 
 as in the brain, nervous system, etc., and that it is 
 not an excretory product, properly so called, and that 
 it fulfils a definite purpose in the organism ; that it is 
 not excreted by the liver, but that some of the 
 cholesterin formed in the organ is secreted with the 
 bile. Cholesterin, mixed with bile pigment, is also 
 the chief constituent of biliary calculi. Eor chemical 
 reactions of cholesterin, see § 51, 
 
 143. Salts. — The inspissated bile extract is to be 
 incinerated, and the estimation of the acids and 
 bases made as dii-ected for blood (§ 101). The chief 
 base is soda, in combination with the bile acids, and 
 which will in the incinerated residue be found aa 
 a carbonate. Sodium chloride is also abundant, and 
 sodium phosphate ; then comes phosphate of lime and 
 magnesia and chloride of pota,ssium. Traces of iron 
 
2o6 Clinical Chemistry. [Chap. v. 
 
 are always present, and are said to be increased when 
 this metal is taken as medicine. Minute traces of 
 silica, and also copper, are stated on good authority 
 to be constantly present. 
 
 144. Biliary calculi will be considered in 
 chapter vi., in the section referring to morbid con- 
 cretions. 
 
 145. Functional d.eraug'enients of the 
 liver. — In addition to the formation of bile, the 
 iiver performs two other important functions, viz., 
 (1) the formation of glycogen; and (2) the meta- 
 bolism of certain albuminous constituents of the 
 body. To these may be probably added another, 
 consisting of certain synthetical processes, by which 
 the carbohydrates are converted into fats, and the 
 peptones transformed into albumins prior to absorp- 
 tion into the blood by a process of deliydration 
 (§1.35). 
 
 (1) Glycogenic, function. — Diabetes. — Although the 
 formation of glycogen is not restricted to the liver, 
 since it has been found in small quantities in other 
 tissues, still, undoubtedly, it is the chief seat of its 
 formation. The only exception to this statement is 
 during the first period of intra-uterine life, when the 
 liver is found free from this substance, whilst sugar is 
 found in the fluid of the allantois and liquor amnii. 
 During the latter period, however, of gestation the 
 liver of the foetus contains glycogen, and sugar dis- 
 appears from these fluids.* It has also been found 
 in the pulmonary tissues of hybernating animals. 
 In the consolidated lung of pneumonia, and in muscles 
 v/hich have been kept long at rest, the quantity is 
 increased. With the resumption of activity, the 
 glycogen in the first case disappears, in the second 
 
 * In the liquor amnii of a diabetic patient, recently confined, 
 which Dr. .John Williams brought to me for examination, no trace 
 of sugar could be found. 
 
Chap, v.] Diabetes. 207 
 
 cliiuiui.slies in quantity. Dr. Pavy has very ingeniously 
 brought forward these facts to show that venous blood 
 is favourable, and oxygenated blood is unfavourable, to 
 its accumulation ; and, since there is no organ in the 
 body su2)])lied with venous blood in like manner to the 
 liver, so, in correspondence, nowliere does glycogen 
 exist to a like extent. In early fcctal life, however, 
 the supply of venous blood to the liver from the 
 chylopoictic viscera is quite insignificant compared 
 with the oxygenated l)lood received from the um- 
 bilical vein, and so glycogen does not accumulate. 
 As ftutal life advances this relationship becomes 
 altered. In hybernatmg animals, and in muscles at 
 rest, a reduced supply of arterial blood also must 
 necessarily prevail. Dr. Pavy has, moreover, pointed 
 out that in the consolidated lung, owing to its im- 
 perviousness to air, the venous blood of the pul- 
 monary artery does not become oxygenated, but 
 retains its venous character, and thus stands in the 
 same position as the portal blood does to the liver. It 
 is important to bear these facts in mind with regard 
 to the origin of diabetes ; for, if a limited supply of 
 oxygenated blood is favourable to the accumulation of 
 glycogen, it is reasonable to suppose, if the opposite 
 condition be ^^I'Psent, and oxygenated or imperfectly 
 de-arterialised blood be passed to the liver through the 
 ■poi'tal vein, rapid transformation of its amyloid sub- 
 stance into sugar will be accomplished, and glycosuria 
 be the result. And this brings us to the question, 
 what is the fate of the glycogen formed in the liver 
 under normal conditions'? The view originally sug- 
 gested by Bernard, and generally accepted by the 
 profession, was that the glycogen was immediately 
 converted into sugar, and this, on reaching the general 
 circulation, was destroyed, the destruction occurring 
 chiefly in the perii)heral capillaries and in the nmscles, 
 leading to the increased production of carbonic acid 
 
2o8 , Clinical Chemistry. [Chap. v. 
 
 and water. Dr. Pavy, on the other hand, maintains 
 that the liver is essentially a sugar-assimilating, in- 
 stead of a sugar-forming, organ^ and, when its assimi- 
 lative action is properly exerted, so little sugar is 
 allowed to pass into the general circulation that the 
 quantity existing in arterial blood is insufficient to 
 allow more than a mere trace to appear in normal 
 urine. The glycogen is stored up in the liver cells, 
 where it presumably undergoes a change which forms 
 one of the links in the series leading up to the final 
 issue ; viz., the utilisation of sugar as a force-pro- 
 ducing agent. 
 
 Now, according to Bernard's view, diabetes 
 would depend on excessive formation of glycogen 
 in the liver, by which an excessive amount of sugar, 
 over and above its power of reduction into carbonic 
 acid and water, would reach the circulation. Whilst, 
 according to Dr. Pavy's view, diabetes is -due to a 
 failure of the assimilative function of the liver, 
 which, instead of storing up glycogen^ allows it to 
 pass off as sugar, and, in proportion as it does so, the 
 uriiie acquires a more or less marked saccharine 
 character. Now, to return to the fact that excess of 
 venous blood is favourable to the storing-up of gly- 
 cogen, whilst oxygenated blood causes its disappear- 
 ance. Dr. Pavy (Proc. Royal Soc.,^\me and Nov., 1875) 
 has shown that, by introducing defibrinated arterial 
 blood into the portal system, strongly-marked glyco- 
 suria was quickly introduced ; and he also established 
 the negative by employing defibrinated venous blood; 
 that is to say, the glycosuria was due to the influence of 
 the oxygenated blood, and not to any other part of 
 the operation. This experiment shows that oxygenated 
 blood reaching the liver through the portal vein is 
 perversive of the proper action and instrumental in 
 producing glycosuria. Dr. Pavy also induced glyco- 
 suria (11 grains of sugar to 1 oz. of urine) by 
 
chnp. v.] Diabetes. • 209 
 
 artificial respiration ; and Titfcnbach has similarly 
 succeeded in obtaining sugar in urine in curarised 
 rabbits. 
 
 But in what manner in diabetes is the liver thus 
 nnduly charged with oxygen i-eaching the liver by the 
 poi'tal vein ? Dr. Pavy considers that the state 
 into which the portal blood is thrown by vaso- 
 motor paralysis aflecting the vessels of the chylo- 
 poietic viscera, is the key to the explanation of the 
 saccharine condition of the urine in diabetes. He 
 says, "It may be observed in the case of division of 
 the sympathetic in the neck, that not only is there a 
 hyperpemic condition of the ear, but that the veins 
 contain much redder blood than natural. In fact, the 
 blood passes with such velocity and in such volume 
 through the aflected part that it does not become de- 
 artei-ialised. A similar state existing in connection 
 with the vessels of the chylojDoietic viscera will give 
 what is sufhcient to produce glycosuria. Without any 
 new agent being brought into question, the simple 
 passage of blood through the vessels in such a mannef 
 as to cause it to arrive in the portal vein in an im- 
 perfectly de-arterialised condition will supply all that 
 is wanted to account for the unnatural passage of 
 sugar. In the vaso-motor paralysis, which, observation 
 shows, is produced by lesions of the nervous system 
 that give rise to glycosuria, we have a condition that 
 leads to the presence of imperfectly de-arterialised 
 blood in the portal vein, and in this condition of imper- 
 fectly de-arterialised blood in the portal vein we have 
 a circumstance that suffices to determine the escape of 
 sugar from the liver in a manner to produce a diabetic 
 state of the urine." Dr. Pavy also considers the 
 bright red appearance of the tongue, so often noticed 
 in severe cases of diabetes, is an evidence of this 
 hypersemic state ; the idea suggests itself from its 
 appearance, that the blood is flowing through the 
 o 
 
2IO Clinical Chemistry. [Chap. v. 
 
 organ without being properly deprived of its arterial 
 character. With regard to the nature of the nervous 
 lesion in diabetes that produces this vaso-motor 
 paralysis nothing definite has been determined. Dr. 
 Dickinson has stated that he has found certain vas- 
 cular and perivascular changes in the brain and medulla 
 oblongata of persons dying from diabetes. His views, 
 however, have been challenged by pathologists, who 
 have found similar changes in brains of those dying 
 from other diseases besides diabetes, and that they 
 are not by any means a constant lesion in diabetes. 
 However this may be, I think the explanation of the 
 persistency of diabetes mellitus, a condition which 
 emphatically distinguishes it from glycosuria, will alone 
 be found to depend on some definite lesion of the 
 nerve centres, either of the cerebro-spinal or sym- 
 pathetic system. - Indeed, it has been suggested that 
 as the vaso-motor nerves distributed in the sympathetic, 
 besides being connected with the spinal cord and 
 medulla oblongata, pass up to spots at the surface of 
 the brain, these possible vaso-motor centres should be 
 examined in all cases of diabetes mellitus. That 
 question must be decided by the morbid anatomist ; in 
 the meantime, the causes that induce glycosuria are of 
 greater interest to the pathological chemist. In these 
 cases it is more than probable that the vaso-motor 
 paralysis is induced directly by the circulation through 
 the portal vessels of toxic agents. Thus, Dr. Pavy has 
 shown that carbonic oxide, which gives to venous 
 blood a bright scarlet colour, and a similar spectrum 
 as oxygen does when introduced into the portal veins, 
 produces glycosuria in as marked a manner as arterial 
 blood ; and phosphoric acid, he has shown, has the 
 same efiect. George Harley has similarly shown that 
 chloroform, alcohol, ether, and ammonia produce 
 temporary glycosuria, so also does curare poison. 
 Although it has not been proved, it is far from unlikely 
 
Chrxp. v.] L/TlfyEMfA. 2 I I 
 
 that uric acid may liave tlio same eHect, and thus 
 account for tlie frequent association of glycosuria with 
 tlie gouty state. Even diminution of tlie alkaline 
 condition of the blood may play an im])ortant part in 
 producing this vaso-niotor paralysis, since it has been 
 shown (Dr. Gaskell ; Journ. Fhj/s., No. 1, vol. iii. ; 
 1880) tliat whilst alkaline solutions cause powerful 
 contraction of the heart and capillaries, dilute acid 
 solutions have a contrary effect ; in this way one can 
 see how disturbance in the circulation between the 
 intestines and the liver, by permitting the acid chyme 
 to pass too rapidly into the portal vessels, might lower 
 the alkalescence of the blood in the portal circidation, 
 and thus cause temporary vaso-motor pai'alysis. In 
 some anomalous forms of diabetes, disease of the pan- 
 creas has been noticed ; the cutting off of this powerful 
 alkaline secretion may have effect of diminishing the 
 alkalescence of the blood in the portal vessels. Glyco- 
 suria is not unfrequently met with in those who have 
 had much mental labour, trouble, or anxiety. Bernard 
 looked upon the appearance of sugar in these cases as 
 a salutary effort of nature to repair the injuries of the 
 organism, but it is far more probable that it depends 
 on a partial vaso-motor paralysis, an expression of the 
 general nervous exhaustion. 
 
 (2) Abnormal disintegration. — Lithcemia. — For- 
 merly it was held that tissue changes depended on the 
 amount of oxygen taken in by the lungs, so that in 
 increased respiration a more intense combustion took 
 place, and metabolism was increased with the pro- 
 duction of more carbonic acid and urea, whilst when 
 respiration was impeded oxydation was imperfectly 
 performed, and as a consequence many of the 
 intermediate products, as Uric acid, oxalic acid, etc., 
 were not burnt off, but were eliminated in an imper- 
 fectly oxydised condition. Upon this view the late 
 Dr. Murchison founded his views regardintr lithcemia. 
 
212 Clinical Chemistry. [Chap. v, 
 
 " When oxydation/' he says, " is imperfectly pei'- 
 formed in the liver there is a production of insoluble 
 lithic acid (uric acid) and lithates (urates) instead of 
 urea, which is the soluble product resulting from the 
 last stage of oxydation of nitrogenous matter. Persons 
 who habitually enjoy the best of health are liable to 
 deposits of lithates (urates) in the urine after a surfeit 
 of food, or even after partaking moderately of one of 
 the fashionable dinners of the age. When more food 
 is taken into the blood than is necessary for the 
 nutrition of the tissues, the excess is thrown off by 
 the kidneys, lungs, and skin in the form of urea, 
 carbonic acid and water, or in the imperfectly oxydised 
 forms of uric acid and oxalic acid. Under these cir- 
 cumstances, an excess of work is thrown upon the 
 liver and the other glandular organs, and one 
 result is that a quantity of albumin, instead of being 
 converted into urea, is discharged by the kidneys in 
 the less oxydised form of uric acid or its salts. But 
 what in most persons is an occasional result of an 
 extraordinary cause, is in some almost a daily occur- 
 rence, either from the food being always excessive in 
 amount or unduly stimulating, or from some innate 
 defect of power, often hereditary, in the liver, in 
 virtue of which its healthy functions are liable to be 
 deranged by the most ordinary articles of diet." 
 
 The doctrine of lithsemia, or, as it ought more 
 properly to be termed, uricfemia, has found consider- 
 able favour with the profession, no doubt from the 
 powerful advocacy of such a distinguished clinical 
 teacher as Murchison; but though the numerous 
 symptoms detailed by him in connection with the 
 deposit of urates in urine are no doubt a matter of 
 common observation, his explanation of the causes 
 giving rise to the condition is not, I venture to think, 
 the correct one. 
 
 It is now known that uric acid is not a necessary 
 
Chap, v.] LiTII/EMlA. 213 
 
 antecedent of uroa, and tliat the latter hndy is 
 larifoly formed, independently of the liver, directly 
 from the kreatin of muscle and from leucin, the 
 result of pancreatic digestion, in the intestines. Nor 
 liave we any evidence, except in the state of actual 
 gout, that, in human blood, uric acid has been ever 
 found ; whilst the view is steadily gaining ground 
 that, with the exception of a small quantity 
 formed in some of the large glands of the body, and 
 in which it seems to be destroyed, uric acid is not 
 formed to any extent, and that the cyanogen residues 
 probably form urea directly without passing through 
 the intermediate stage of uric acid. Again, if uric acid 
 is found in excess in the urine because it has not been 
 oxydised into urea, we should certainly expect to find 
 the urea diminished in these cases ; but this is not 
 so. In every analysis I have made myself, and in 
 others that I have referred to for the purpose of 
 ascertaining this point, I have found that, whenever 
 uric acid is increased, urea is likewise in excess, not 
 always proportionately, but still sufficiently decided as 
 to show there is no reduction in quantity. 
 
 The explanation I have to suggest as a cause for 
 the group of symptoms so admirably portrayed by 
 Murchison is, that they are due to a disturbance of 
 the nitrogenous equilibrium, brought about by an 
 increase of metabolic processes throughout the body, 
 owing to an intramolecular activity in the cells (§ 7). 
 This condition may be transient, and caused by in- 
 discretions of diet, nervous influences, or temporary 
 disturbances in some function of the organism ; but, 
 when we have a persistent tendency to deposit urates, 
 accompanied by increased urea and phosphates, we 
 nmst look beyond mere defective oxydation or func- 
 tional disturbance of the organ for an explanation, 
 and view it as a prelude of some grave constitutional 
 disturbance (often cancer, tubercle, or constitutional 
 
2 14 Clinical Chemistry. [chap. v. 
 
 syphilis), the taiiit of which produces increased mole- 
 cular activity throughout the body. This question of 
 lithseniia I have discvissed from its clinical aspect in 
 my work on " Morbid Urines associated with Derange- 
 ments of Digestion," pp. 68 — 76, and to which I 
 refer the reader, as that part of the subject cannot be 
 introduced here. 
 
 As a converse to the conditions we have been 
 speaking of is one characterised by a urine of low 
 specific gravity, with no tendency to deposit uric acid 
 or urates, and which is very deficient in urea, and 
 associated with peculiar symptoms, which Sir Andrew 
 Clarke has succinctly grouped together under the term 
 " renal inadequacy." The term is an expressive one, 
 and fixes in the mind the condition of the urine ; b\it 
 I venture to think in this case we may go a step 
 farther, and refer the inadequacy to failure in part of 
 the metabolic processes going on throughout the body, 
 and in part to defective assimilation of food by the 
 digestive organs. Another evidence of abnormal dis- 
 integration is occasionally seen in cases of temporary 
 albuminuria, and which are sometimes accompanied 
 by the presence of peptones in urine. This condition 
 is often of a transient nature, and dependent on 
 marked disturbance of the hepatic function. In other 
 cases, from being at first of a temporary and inter- 
 mittent character, it becomes more and more jDer- 
 sistent, as to give rise to a suspicion that it is a pre- 
 liminary or early stage of granular kidney. Nor is it 
 at all unlikely that this functional albuminuria may 
 not at last terminate in organic disease. Ha)matinuria, 
 too, is another condition which may be assumed to 
 depend on functional derangement of the liver. In this 
 disease (§ 120, page 161), only the colouring matter of 
 the blood is present in the urine, and no blood corpuscles 
 are to be found, whilst the colouring matter itself is 
 apparently undergoing a change ; for, in addition to 
 
Chap, v.] Pancreatic Juice. 215 
 
 the spt'ctrum of oxy-hsemoglobin, there is aLso a third 
 blind present, representing meth.ienioglobin. These 
 cases are usually attended with well-marked dyspeptic 
 symptoms and slight jaimdice, and generally follow 
 exposure to cold or chill. If, therefore, we regai-d the 
 liver as the seat of the disintegration of the eflete 
 blood-corpuscles, with the formation of hsematin, and 
 then of urobilin, it is not unreasonable to assume that 
 a sudden interference with the function of the liver 
 may temporarily arrest the process of the conversion 
 of haemoglobin into bile and urinary pigment, and so 
 permit it to pass again into the circulation, to be 
 eliminated by the kidney. 
 
 146. Pancreatic juice. — A thoroughly reliable 
 analysis of the secretion of pancreas is wanting, 
 owing to the fact that the slightest irritation of the 
 gland caus(^s considerable changes in the character of 
 the secretion. Thus, Ewald, at the same period of 
 digestion in about equally large dogs, obtained some- 
 times a copious, sometimes a scanty, secretion, with- 
 out being able to assign any cause for the difference. 
 It will, therefore, be sufficient to state that the 
 amount of solids in the pancreatic juice of dogs, 
 obtained from permanent fistulte, ranges from 3 to 10 
 per cent. Of these, the organic constitute about 
 two-thirds, and the inorganic one-thii-d. Of the or- 
 ganic solids, the most important are the ferments, 
 which act on starch, fat, and albumin ; ordinary 
 albumin, an albumin precipitable by magnesium sul- 
 phate (casein or seroglobulin %) ; fatty matters ; and 
 leucin and tyrosin.* Of the inorganic constituents, 
 sodium carbonate is in relative excess of the other 
 salts. The juice, when obtained free from the 
 products caused by the irritation of the duct, is a 
 
 * These bodies are not always present. They seem to be 
 formed by the action of the proteid ferment on the albuminous 
 constituents of the secretion after it has been collected. 
 
2i6 Clinical Chemistry. [Chap. v. 
 
 clear, somewliat viscid fluid, free from smell, having a 
 marked alkaline reaction. 
 
 The ferments of the pancreatic juice can be 
 obtained from the glycerin extract of the pancreas 
 of a freshly-killed animal. 
 
 (1) Action on starch is most energetic, and sur- 
 passes that of the saliva (§ 131). The ferment has 
 been isolated in a state of tolerable purity. It is 
 stated that, after the pancreas has been exhausted by 
 glycerin, if left exposed to the air for some time, it 
 will again yield the diastatic ferment. From this, it 
 is argued that the pancreas contains a body which by 
 decomposition is converted into a ferment, analogous 
 to the process that occurs in the liver by the con- 
 version of glycogen into glucose (Liversidge ; Jour. 
 Anat. and Phys., vol. viii., 1872). 
 
 (2) Action on fats. — The ferment that acts on fat 
 has not yet been isolated. Its action, however, can 
 be studied with the fresh juice, by mixing it with a 
 little of a neutral fat in a test-tube, and placing the 
 mixture in a water-bath (40° 0.). At the commence- 
 ment of the process the mixture is slightly alkaline, 
 and neutral to litmus ; but, as digestion proceeds, it 
 becomes acid from the splitting up of the fat into 
 glycerin and fatty acid. 
 
 (3) Action on jji-oteids. — In dilute alkaline solu- 
 tions, the ferment converts proteid bodies into pep- 
 tones, similar to those formed by pepsin in acid 
 solutions, dilute solution of sodium carbonate, O'l 
 per cent., playing the same part as dilute hydro- 
 chloric acid does in gastric digestion. The points, 
 however, in which pancreatic digestion differs from 
 gastric digestion are, that the proteid elements do not 
 swell up, become translucent, and fibrillate, as in the 
 case of digestion with pepsin, but remain opaque, and 
 apparently undergo conversion from the edges by a 
 process of erosion. Again, the bye-product, anti- 
 
ciiap. v.] Pancreatic Juice. 217 
 
 albumose (or parapeptone) is of an alkaline character, 
 resembling alkali, albumin, or casein, and not acid 
 albumin or syntonin, as in gastric digestion. Lastly, 
 the continued action of pancreatic ferment leads to 
 the formation of leucin and tyrosin from the breaking 
 up of the hemipeptone. The following table shows 
 in a graphic form the changes efiected on proteid 
 substances respectively by gastric and pancreatic 
 digestion : 
 
 Albumin. 
 
 Anti-albumose Hemi-albumose 
 
 or or 
 
 (parapeptone) (Meissner's a peptone) 
 
 I ' 1 I 1 
 
 Anti-peptone Anti-peptone Hemipeptone Hemipeptone 
 
 or or ^ f Leucin Indol 
 
 (true peptone) (true peptone)"© 2 Tyrosin Phenol 
 
 Hypoxantbin Naphthilamine 
 
 Asparaginic Sul])huretted 
 
 acid hydrogen 
 
 Glycocoll Carbonic acid 
 
 d c3 
 
 QT, g Normal diges- Putrefactive 
 Pi l^ tive products. products. 
 
 Thus the final action of the pancreatic ferment is 
 to break up the hemipeptone formed by its own 
 digestive action, and the hemipeptone formed by 
 gastric digestion, into a series of bodies related to the 
 group of fatty acids (leucin = amido-caproic acid) and 
 the aromatic series (tyrosin = amido-propionic acid in 
 "which one atom of H is replaced by oxy-phenol). The 
 formation of indol, phenol, etc., is, however, regarded 
 as due to putrefactive changes, and not to normal 
 pancreatic digestion, since the production of these 
 substances is simultaneous with the appearance of 
 organisms in the solutions. These organisms are 
 probably taken in with the food and find a habitat in 
 the intestines ; they do not exist in the pancreas. The 
 chemical reactions of the true peptone formed by 
 
2i8 Clinical Chemistry. [Chap. v. 
 
 pancreatic digestion are similar to that formed by the 
 gastric juice (§ 135;, page 186). The pancreatic ferment 
 dissolves mucin ; and, according to ISTencki, converts 
 gelatin into a peptone and glycocoll. It has, like 
 pepsin, no action on lardacein, nuclein, or keratin. 
 
 The pancreas is an organ about which the patho- 
 logical chemist has little to say as yet. Fatty dege- 
 neration and atrophy of the gland has been noticed 
 by Bright, Frerichs, Catani, and numerous other ob- 
 servers, in some cases of diabetes. By some it is attri- 
 buted as the result of that disease. At page 211 I 
 have suggested how possibly diminution of the pan- 
 creatic secretion may induce glycosuria, by dimin- 
 ishing the alkaline reaction of the blood in the portal 
 vessels from the absorption of the contents of the 
 jejunum not having been neutralised by this secretion. 
 In cases of obstruction of the duct of the pancreas an 
 increase of fatty matters has been noticed in the 
 stools ; but there are exceptions to this statement. 
 The matter of chief clinical interest, which ought to 
 be more fully worked out, is the formation of urea 
 from the leucin derived from pancreatic digestion, and 
 the formation of indol, and its appearance as indican 
 in the urine. With regard to the latter, it has been 
 shown that as salicylic acid puts a stop to the forma- 
 tion of indol in albuminoid solutions of pancreatic 
 juice, so the internal administration of the same acid 
 reduces the amount of indican in the urine, which 
 decreases exactly in proportion as the quantity of 
 phenol increases. Indican is also met with in the 
 urine after ligature of the small intestines, and in 
 obstructions and other affections of the intestines in 
 disease. The indigo sometimes deposited in a free 
 state in urine, sweat, and urinary calculi, is undoub- 
 tedly derived from the indol formed in the intestines 
 by pancreatic digestion. The indol apparently is 
 converted into indican in the alkaline blood, which 
 
Chap, v.] Tnte^tinat. Dicfstion. 219 
 
 is comcrted into iiuli^ijo, if prosciit in oxcfss, 
 wlu'u it comes in contact with highly acid sweat or 
 urine. 
 
 147. Infostiiisil diH:o«»tion. — Very little is 
 known regarding the composition of the secretion 
 furnished by the intestinal glands. According to 
 Thirry the succus entericiis is a yellowish opalescent 
 Huid of alkaline reaction, having a specific gravity of 
 1-011, and contains about 2-5 per cent, of solids. 
 It dissolves tibrin, but it is a question whether it has 
 any action on other proteid bodies. Its diastatic 
 action on starch is doubted. It is said, howevei-, 
 to convert cane sugar into grape sugar and in- 
 vert sugar, and to set up lactic acid fermentation. 
 Absorption of the digested products takes place 
 tlirougliout the intestinal canal, but tlie process 
 must be considered with reference to particular 
 tracts : — (1) The duodenum ; (2) the jejunum 
 and upper part of the ileum ; (3) the lower part 
 of the ileum and the large intestine. (1) In the duo- 
 denum. — In the stomach most of the ditiusible sugars, 
 and some of the peptones, pass directly into the 
 gastric veins ; but the remainder, consisting of para- 
 peptone, the undigested albumin, the starchy prin- 
 ciples which have as yet escaped conversion, and the 
 oleagineous matters, pass through the pyloric orifice 
 into the duodenum as acid chyme. On reaching the 
 biliary orifice a rush of bile takes place, which causes a 
 precijjitation of the parapeptone, at the same time the 
 pancreatic secretion is poured forth in abundance. 
 The action of these two alkaline secretions has the 
 efl'ect of first neutralisinij the acid and then rendering 
 the contents of the intestine alkaline. In the mean- 
 time, the emulsionising and saponification of the fatty 
 matter is proceeding, and the chyme passes into (2) 
 tJie jejunum and upper jJCiTt of the ileum as chyle. It 
 is liere that tlie final digestion of the food is effected, 
 
2 20 Clinical Chemistry. [Chap. v. 
 
 the pancreatic juice converting the undigested albu- 
 min and some of the gastric peptone into anti-peptone 
 and hemipeptone, which last is converted into leucin, 
 tyrosin, etc. The starch is converted into grape 
 sugar, so is, probably, part of any cane sugar present, 
 whilst a portion commences to undergo lactic fermen- 
 tation. The fats meanwhile are thoroughly emulsified 
 and saponified. These products are quickly absorbed, 
 the peptones, the glucose, and a dextrin-like body, pass- 
 ing chiefly in the direction of the portal vessels, whilst 
 the emulsioned fat is taken up by the lacteals. (It is 
 a question whether the saponified matters are taken 
 up, or whether saponification is only subsidiary to 
 emulsion.) In the absorption of fatty matter the 
 bile acids undoubtedly play an important part by 
 aiding their passage through the absorbents. As 
 the fluid contents pass onward they gradually 
 lose their nutritious constituents, till at (3) the 
 lower part of the ileum and large intestine they 
 become more consistent and contain little besides the 
 insoluble residue of the food and the putrefactive 
 products, indol, etc., of pancreatic digestion. The 
 reaction, too, here again becomes acid from the lactic 
 acid fermentation set up in the intestine. Although 
 the process of absorption is very inconsiderable, 
 still it exists to a very appreciable extent, as is 
 decidedly proved by the beneficial result nutritive 
 enema have for a time on patients who cannot other- 
 wise be fed. 
 
 148. The faeces consist of that portion of the 
 food which is not taken up by the absorbents, and is 
 discharged from the body mixed with some of 
 the products of the biliary and intestinal secretions. 
 Their amount must necessarily depend on the nature 
 of the food taken, and on the energy of the digestive 
 powers. The quantity passed by a healthy adult 
 may be, however, stated r.t from 7 to 9 ounces daily. 
 
Chap. V.J F^CES. 2 2 1 
 
 The colour ought to be a rich brown, and the surface 
 of the motion moist and slightly slimy. The odour 
 varies considerably in different persons ; in some, even 
 in the healthy, it is particularly strong and offensive. 
 Thig^ odour is chiefly derived from the putrefactive 
 changes occurring in the intestine, and partly to a 
 secretion of the glands of the large intestine. Those 
 who make it their duty to inspect the stools of their 
 patients will soon learn to recognise an odour sui generis 
 attached to many disorders ; thus, it is easy to distin- 
 guish by smell alone a dysenteric from a typhoid 
 stool, etc. The follo-sving is an approximate analysis 
 of the fjeces of a healthy adult : Water, 77-3 ; Solids, 
 22-7; mucin 2-3, proteids 5*4, extractives 1-8, fats 
 1-5, salts 1-8, resinous, biliary, and colouring matters 
 5 '2, insoluble residue of food 4 "7. 
 
 (1) Albumin. — A small quantity of coagulable 
 albumin is always present in normal fteces, whilst in 
 cases of dysentery, typhus, and cholera, the quantity 
 passed is considerably increased. 
 
 (2) Extractives. — Besides the occasional presence 
 of leucin, certain fatty acids, substances called ex- 
 cretin, and stercorin, are present. The following is an 
 account of these substances and mode of separation, 
 though many are sceptical as regards their existence 
 in a definite form, but consider them to be modifica- 
 tions of cholesterin. {a) Stercorin. First described 
 bv Dr. Flint, who assumes that under ordinary 
 circumstances about 0'6 gramme is excreted daily. 
 Dr. Flint directs the f«ces to be evaporated to 
 dryness, pulverised, and exhausted with ether. 
 The etherial solution is then passed through animal 
 charcoal, fresh ether being added, until the original 
 quantity of ether extract has passed through. The 
 filtered etherial solution is then evaporated, and 
 the residue treated with boiling alcohol. The 
 alcoholic solution is evaporated, and the residue 
 
22 2 Clinical Chemistry. [Chap. v, 
 
 treated with a warm, solution of caustic potash to 
 dissolve out all the saponifiable fats. The mixture 
 is then diluted with water, thrown on a filter, and 
 washed till the droppings are clear and neutral. The 
 filter is dried, and the residue washed out with ether. 
 The etherial solution is then evaporated, and the 
 residue treated with boiling alcohol, the residue of 
 this solution yielding stercorin. Stercorin, when thus 
 obtained, appears as a clear, amber-coloured, oily 
 substance, in ,which thin, needle-shaped crystals, fre- 
 quently arranged in bundles, and having their borders 
 split longitudinally, appear in the course of a few 
 days, Stercorin is neutral, soluble in ether and hot 
 alcohol, insoluble in water and solutions of potash ; it 
 is distinguished from cholesterin by having a lower 
 melting point, viz, 38° 0, Treated with strong 
 sulphuric acid it gives a red colour, Dr, Flint con- 
 siders that stercorin is formed by a modification 
 of cholesterin in its passage along the intestinal 
 canal ; since a comparison of the total quantity of 
 cholesterin contained in bile with the quantity of 
 stercorin actually discharged shows a correspondence. 
 (&) Excretin. This principle was obtained by Dr, 
 Marcet, together with excretolic acid, from faecal 
 matter. The faeces are first dried and exhausted with 
 boiling alcohol, and the alcoholic solution concentrated, 
 filtered, and allowed to stand ; after some time a 
 granular, olive-coloured, fatty acid, excretolic acid, is 
 deposited. This substance melts at 25°, is insoluble 
 in water and in solutions of potash, and in cold 
 alcohol ; its composition has not yet been determined. 
 The excretolic acid must be removed by filtration, and 
 the filtrate treated with milk of lime, which throws 
 down a brown precipitate ; this is dried and exhausted 
 with ether, which yields crystals of excretin. The 
 crystals form delicate, silky, four-sided prisms, in- 
 soluble in water and solutions of potash, very soluble 
 
Chap, v.] FMCES. 223 
 
 in ctlior ; tlicy melt at 95", and liave an alkaliuo 
 reaction. 
 
 3. Tlio fats contain saponifiable fats, and a vory 
 considerable proportion of cholesterin. 
 
 4. The inoryanic constituents contain a very 
 considerable amount of magnesium and calcium 
 phosphate, the former chiefly in the form of ti-iple 
 phosphate. The fa>ces are the only instance in the 
 animal tissues and fluids in which the magnesium 
 salts are relatively in excess of the calcium salts ; this 
 is owing to more lime than magnesia being absorbed 
 in the intestines. The potassium salts are also 
 relatively in excess of the sodium salts. The biliary 
 acids appear in the faeces in an altered condition, 
 as dyslysin, cholalic, and cholodinic acids. The in- 
 soluble residue consists of undigested muscular fibre, 
 the outer envelope of vegetable cells and fibres, 
 partially dissolved starch, cells of cartiLige, and 
 fibres of elastic tissue, etc. Faeces sometimes con- 
 tain a ferment like pepsin, and one that has a dia- 
 static action on starch ; both are probably derived 
 from the digestive secretions. Meconium, or the 
 faecal matter at birth, consists almost entirely of 
 biliary matter and mucus. Thus, a sample of dry 
 meconium yielded ; Biliary matter, 15*6 ; cholesterin, 
 15*4 ; mucus epithelium and salts, 69 parts in 100. 
 
 "We have very few reliable analyses of faeces in 
 disease, few having courage to piirsue diligently such 
 an unpleasant business. As a rule we learn much by 
 regular inspection ; and if the i)lan adopted at the 
 London Hospital, of placing them in large deep conical 
 vessels, and covering the mouth of the vessel with a 
 thick glass plate, inspection can be made without 
 unpleasantness being occasioned, especially if with 
 loose stools a little ether is floated over them. 
 In liquid stools the more solid contents gravitate 
 first, and so on, so that a rough analysis can be 
 
2 24 Clinical Chemistry. [Chap. v. 
 
 made. If a more intimate acquaintance with the 
 composition of the ffeces is desired, they must be 
 submitted to regular analysis ; viz. : (1) By ascer- 
 taining the amount of water and solids (§ 92) ; 
 (2) by agitating in water for some time a definite 
 weight of feeces, filtering the aqueous solution, and 
 coagulating the dissolved albumin, and weighing 
 n as directed (§ 118, page 145); (3) extracting with 
 ether to remove fatty matters and cholesterin (§ 99) ; 
 (4) after the removal of the cholesterin, extracting 
 successively with boiling alcohol and chloroform to 
 remove biliary matters (page 198); (5) whilst the salts 
 are estimated after incineration, as directed (§ 101). 
 
 149. Intestinal concretions will be con- 
 sidered in chapter vi., in the section referring to 
 morbid concretions and calculi. 
 
 1.50. Oases in stomacb and intestines. — 
 As has been well observed, though yeast fungi are 
 continually being taken with the food, as in bad beer 
 or bread, and are thus brought in contact with the 
 saccharine and albuminous matters of the food, which 
 are capable of fermenting in the stomach, fermenta- 
 tion does not occur unless another condition is added. 
 The ferment must have time and opportunity for 
 developing itself. Under ordinary circuuistances it is 
 so rapidly removed from the stomach, together with 
 fei-mentable material, that the process has no time to 
 commence. The conditions, therefore, that favour the 
 development of fermentation are those which retard 
 digestion either by mechanically obstructing the 
 onward passage of the food, or from an abnormal 
 condition of the digestive secretions, or the indigestible 
 nature of the food itself. From experiments, we learn 
 that under normal circumstances the gases found in 
 the stomach consist of oxygen, nitrogen, and carbonic 
 acid, but no hydrogen, which we would expect to find 
 if the gases of the stomach in health were formed by 
 
Chap. V.J 
 
 Fla tus. 
 
 225 
 
 lactic acid fcrmontation. It is probaMc, tliercfore, 
 that of tho gasos olitainod from the stomach under 
 normal conditions, the first two arc derived from the 
 air swallowed with the food, whilst the latter is 
 derived by difTusioii from the blood. In the small 
 intestine, however, acetic and lactic acid fermentation 
 commences, as is shown by the preponderance of 
 carbonic acid gas, and the presence of hydrogen. The 
 following table gives the result of Planer's analysis of 
 the gases of the stomach and intestine respectively : 
 
 
 Stomach. 
 
 Small intestine. 
 
 Gas. 
 
 Moat. 
 
 Bread. 
 
 Meat. 
 
 Vegetable diet. 
 
 CO2 
 N 
 
 H 
 
 2o-20 
 
 68-68 
 
 6-12 
 
 Nil 
 
 32-91 
 
 66-30 
 
 -79 
 
 NH 
 
 40-1 
 45-5 
 Trace 
 13-86 
 
 47-34 
 3-97 
 
 48-69 
 
 The steps that occur in this pi'ocess of fermentation 
 are shown in the following table, thus : 
 
 Sugar C^U^.X), 
 
 2 (CHgO) Alcohol + 2 COo 
 CaH'gO + = CoH^O Aide- 
 
 hi/de + JI.,0 
 C2H4O + = C^U^OoAcetic 
 
 acid. 
 
 2 (CjHgOg) Lactic acid 
 
 CjH'gO., + 2 CO2 + H Biitt/ric 
 acid, carbonic acid, and hydro- 
 gen. 
 
 The occurrence of this lactic and butyric acid 
 fermentation in the small intestine in health, suggests 
 a way in which the carbohydrate constituents of food 
 may become converted into fat ; for, by this lactic 
 and butyric acid fermentation, the sugar is converted 
 into members of the fatty acid series. The extent, 
 however, to which this fermentation is carried on in 
 
226 Clinical Chemistry. [Chap. v. 
 
 health is probably small, since if it occurred largely in 
 the intestine we should have a considerable quantity of 
 free hydrogen excreted by the lungs or bowels, which is 
 not the case. The fermentative changes reach their 
 highest point in the large intestine, so much so as to 
 render its contents acid, in spite of the alkaline 
 character of the secretion from its walls. Here, in 
 addition to hydrogen, we have a considerable quantity 
 of marsh gas (CH4) developed with sulphuretted 
 hydrogen (HjS), from the decomposition of the 
 albuminous and other sulphur-yielding elements of 
 the food. 
 
 In disease, however, excessive fermentative changes 
 of the food may occur, leading to the production of 
 enormous quantities of gas and the formation of 
 various intermediate products, as we have seen, such 
 as alcohol, aldehyde, and acetic acid on the one hand, 
 and of lactic and butyric acid on the other. Some- 
 times it is a large quantity of gas that is formed, at 
 another time an excess of acid. Thus, Ewald speaks 
 of a patient who pithily observed that " there was 
 sometimes a vinegar factory and sometimes a gas- 
 works in his inside ; " in fact, at one time alcoholic 
 fermentation led to the formation of acetic acid, at 
 another, the butyric acid fermentation produced 
 hydrogen and carbonic acid. It is often difficult to 
 distinguish clinically between the different forms of 
 flatulent distension which arise ; but we receive con- 
 siderable aid if we are careful to discriminate between 
 those forms where flatulence is the only symptom and 
 those where it is associated with acidity, and also by 
 taking into consideration the period with regard to 
 digestion at which these symptoms develop. Thus, 
 there are some persons, chiefly females, who, im- 
 mediately on taking food, complain of flatulent 
 distension without acidity ; the wind they bring 
 up is inodorous. In these cases, the gas does not 
 
Chap. V.J FlA TUS. 227 
 
 apparently result from fermentative changes, but is 
 probably derived by diffusion from the blood under 
 nervous influences. When the flatulency is accom- 
 panied by a slight degree of acidity, and sets in about 
 an hour after food, and the risings are simply acid, 
 and the eructations comparatively inodorous, acetic 
 and carbonic acid fermentation of the amylaceous 
 and saccharine materials of the food is indicated. 
 When the risings ai'e distinctly rancid, it is evidence 
 that lactic acid fermentation of the nitrogenous prin- 
 ciples is progressing. This forua of fermentation is 
 usually the most obstinate and severe, since it may 
 continue independently of food by the decomposition 
 of the mucus in the stomach and the intestinal canal, 
 so that flatulence may persist even when the stomach 
 is kept empty. 
 
 Flatulent distension of the stomach and intestines 
 often arises in nervous states of the system, appa- 
 rently, however, quite independently of any fermen- 
 tative changes occurring in the alimentary canal. 
 Indeed, it is quite impossible to account for the 
 enormous quantity of gas, which consists largely of 
 carbonic acid, often discharged through the mouth on 
 a perfectly empty stomach by hysterical and hypo- 
 chondriacal patients, except on the supposition that it 
 is diffused from the blood. 
 
 The disturbances caused by fermentative ' changes 
 in the stomach are not limited to that organ. The 
 acid products formed in. it, together with the un- 
 digested residue of the food, pass on into the in- 
 testines, and excite more or less pain and diarrhoea. 
 Again, fermentative changes may occur chiefly in the 
 intestines, and only a slight degree in the stomach. 
 In this case, which is associated with a greater or less 
 degree of chronic intestinal catarrh, a constipated 
 condition of the bowels generally exists ; for, though 
 there may be frequent loose, slimy, and offensive 
 
228 Clinical Chemistry. [Chap. v. 
 
 discharges from the bowels, yet a purge never fails to 
 bring away accumulated masses of fsecal matter. The 
 whole of the intestinal tract may be aflfected, or only 
 part of it. Some writers have asserted that the evil 
 effects of fermentative changes are more felt in the 
 small intestines than in the large, and that catarrh of 
 the .small intestines is generally associated with 
 oxaluria. The flatulence may distend the whole 
 intestinal tract, but one part of it is generally dis- 
 tended more than another; and circumscribed swell- 
 ings occur, chiefly in the right and left hypochondriac 
 regions, causing pain over the region of the liver and 
 stomach, spleen, or kidneys, and leading the patient 
 to suspect disease of these organs. But the mischief 
 resulting from excessive formation of acid in the 
 stomach and bowels is not limited to mere disturbance 
 of digestion, injurious effects making themselves 
 manifest on the system and on the general nutrition 
 of the body when the morbid condition has been 
 present for some time. 
 
 Thus, Beneke* has pointed out that the increased 
 production of lactic and butyric acids in the alimen- 
 tary canal is frequently associated with oxaluria {§ 112, 
 page 130), since, as he thinks, the excessive formation 
 of these acids prevents the development of the red 
 corpuscles, so that oxydation is insufficiently performed. 
 A catarrhal condition of the mucous membrane of 
 the intestines he also pointed out as being freqiiently 
 found accompanying this condition ; he does not, how- 
 ever, consider it as being a proximate, but only a 
 determining, cause of the disorder. Whilst endorsing 
 Beneke's statement that deposits of oxalate of lime 
 are met with in persons suffering from dyspepsia, at- 
 tended with excessive formation of lactic and butyric 
 
 * "Zur Phys. und Path, des Phosphors und Oxalsaure 
 Kalkes." 1850. "Zur Entwicklungsgeschichte der Oxalurie." 
 185« 
 
Chap. V.) Bilious Attacks. 229 
 
 acids, T do not consider his explanation to be the 
 correct one, since, in these cases, 1 believe a catarrhal 
 condition of the mucous membrane of the digestive 
 canal to be the proximate cause, which, by hindering 
 the onward passage of the food, favours fermentative 
 changes and the production of lactic and butyric 
 acids. 
 
 Again, the highly acid fluid containing the 
 imperfectly digested products of gastric digestion 
 passing into the duodenum excites more or less 
 catarrh of that portion of the intestine, and the 
 discharge of bile is interfered with ; hence persons 
 suffering with flatulent dyspepsia have usually sallow 
 complexions, complain of pain in the hepatic region, 
 and suffer frequently from so-called " bilious attacks." 
 The absorption of the vitiated products of digestion, 
 together with some of the free acid, produce many 
 general and remote disorders of nutrition, so that 
 a condition of debility and exhaustion is speedily 
 induced. 
 
 151. Detection of arsenic, antimony, etc., 
 in the viscera. — A plan of procedure for the 
 examination of vomited matters by which the 
 student or practitioner can ascertain the nature 
 of the poison, without the expenditure of much 
 time or the employment of elal:)orate apparatus, 
 has been detailed § 136, page 191. Of course, it is 
 understood that these investigations are only pre- 
 liminary to a more searching investigation in the 
 chemical laboratory at the hands of an expert. In ad- 
 dition to the examination of the vomited matter ejected 
 during life, we should also make an examination of the 
 tissues, es])ecially of the viscera, after death, especially 
 if, as is sometimes the case, the vomited matters have 
 been thrown away without having been examined, and 
 the patient having lived some hours after the poison h;is 
 been absorbed from the stomach into the tissues. For 
 
230 Clinical Chemistry. [Chap. v. 
 
 this purpose portions of the liver and stomach must be 
 divided as finely as possible and placed in a porcelain 
 dish, and a mixture, about twice the quantity of the 
 organic matter employed, consisting of six parts of dis- 
 tilled water to one of hydrochloric acid, is added, and 
 the whole warmed for about an hour. After this, small 
 fragments of potassium chlorate are to be dropped into 
 the mixture from time to time, and the mixture 
 kept constantly stirred, till the solid matter has 
 almost completely disappeared. The mixture is then 
 filtered through fine linen, the insoluble matter left 
 oh it being kept for further examination, and the acid 
 filtrate divided into three parts : (1) Place in the 
 acid mixture a strip of perfectly pure copper and boil 
 for twenty minutes ; if there is a deposit on the copper 
 examine for arsenic, antimony, or mercury. Remove 
 the strip of copper, wash it with a little distilled water 
 to which a few di'ops of ammonia are added, dry it 
 between folds of blotting paper, then when quite dry 
 place it at the bottom of a narrow glass tube ( German 
 glass), and apply heat to the lower portion of the tube, 
 taking care that the upper end remains cool, and 
 placing the finger lightly over the mouth of the tube, 
 so as to keep the volatilised matters within it. If 
 arsenic, forms the crust on the copper, then arsenious 
 acid will sublime and be deposited at the upper end of 
 the tube, and this deposit under a low power of the 
 microscope will be found to consist of sparkling octo- 
 hedi-al crystals. Break ofi" the portion containing the 
 deposit and boil it in a test-tube for some minutes 
 with distilled water. Test aqueous solution with (a) few 
 drops of silver ammonium nitrate, which gives a bright 
 yellow precipitate, soluble in ammonia and nitric acid ; 
 (6) solution of cupric ammonio-sulphate, which gives a 
 pale apple-green precipitate. If arsenic has been found 
 it will be as well to take a fresh portion of acidulated 
 filtrate and submit it to Marsh's test. If the crust 
 
Chap. V.) SePARA TION OF METALLIC FoiSONS. 23 I 
 
 deposited on the copper is caused by antimony, it does 
 not, by heatinij, yield a crystalline, but an amorphous 
 deposit, and tliis, on the application of a greater 
 degree of heat than was required to volatilise the 
 arsenic. To ])rove the presence of antimony, break 
 off the upper end of glass tulie, boil it with dis- 
 tilled water very slightly acidulated with hydrochloric 
 acid. Through this acid solution pass a stream of 
 sulphydric acid, when an orange-coloured precipitate 
 will fall. If the deposit on the copper is caused by 
 niercuri/, on volatilisation distinct globules will form 
 in the upper part of the tube ; for corroboration apply 
 tests given § 132, page 177. If no result has been ob- 
 tained by boiling the copper in the acid filti-ate, take 
 a fresh portion (2) of the acid solution and warm it 
 and pass a stream of sul))hydric acid through it. A 
 black precipitate indicates copper or lead. If copper, 
 on dipping the blade of a knife in the acid solution, 
 which should be concentrated, it will be deposited 
 on the surface. Ammonia added gives, with solution 
 of copper, a light blue precipitate, soluble in excess 
 of ammonia with the formation of deep blue solution. 
 Potassium ferrocyanide gives, with solution of cupric 
 salts, a reddish-brown precipitate. This test is 
 employed to show that all the copper has been de- 
 posited from the standard Fehling solution in quan- 
 titative estimation of glucose (§ 119, page 153). If the 
 black precipitate is not caused by a salt of copper, then 
 test solution for lead as directed § 129, page 172. 
 If no precipitate is caused by sulphydric acid a 
 solution of ammonium hydro-sulphate is to be added ; 
 if a zinc salt is present a white or yellowish-white 
 })recipitate will be thrown down. (3) The acid 
 nitrate is to be concentrated to a small bulk, and is 
 then rendered alkaline by potash and shaken with five 
 times its volume of ether. The etherial solution is 
 then removed and allowed to evaporate spontaneously 
 
232 Clinical Chemistry. [Chap. v. 
 
 in a small glass dish and the solid residue examined 
 for strychnine or morphia by dissolving it in a little 
 dilute hydrochloric acid, rendering this solution alka- 
 line by sodium carbonate and allowing the mixture 
 to stand till a crystalline precipitate forms. This 
 is to be collected on a small filter and washed till 
 the washings are no longer alkaline. Then divide the 
 filter into two parts and lay them on white porcelain 
 plates and test respectively for morphia (§ 70) and 
 strychnia (§ 71). The filtrate and the washings are 
 mixed together and evaporated to dryness in a water- 
 bath, and the dry residue warmed with alcohol ; the 
 alcoholic solution is then to be evaporated to dryness 
 and the tests for morphia and strychnia applied. 
 
 1 5 2 . E stiinatioii of iiitro g'en. — In some physio- 
 logical and pathological enquiries, we wish to compare 
 the quantity of nitrogen passed out of the system with 
 the faeces and urine, with the amount of nitrogen taken 
 in with the food. For these investigations the soda- 
 lime process, devised by Yoit, is the best. For this 
 purpose a sm-all tubular retort, the bulb of which is 
 about 6 centimetres deep, and 3 "5 centimetres broad, 
 with the neck bent at right angles about 10 centi- 
 metres from the bulb, and drawn out into a fine tube 
 8 centimetres long, and 0*3 centimetres in diameter, 
 has placed in it some soda-lime, recently heated to 
 redness, to the depth of 1'5 centimetres. The narrow 
 tube of the retort is then fitted to a glass flask (of 
 150 cc. capacity) by means of a perforated cork. The 
 delivery tube of the retort should pass down almost 
 to the very bottom of the flask. By means of a 
 second hole in the cork a glass tube is fixed which is 
 adjusted so as to be above the level of the fluid. The 
 apparatus being arranged, 100 cc. of standardised 
 dilute sulphuric acid is poured by means of the glass 
 tube into the flask, and then 5 cc. of urine (or in the 
 case of faeces or food 5 grms., weighed dry, and 
 
Chap, v.] Estimation of Nitrogen. 233 
 
 afterwards mixed in 5 cc. of wati-r) ai-e poured on tlio 
 soda-liuio. The mixture at once becomes warm and 
 ammonia is disenfj;aged, which passes over into the 
 flask where it bul)l)les up through the dilute sul])huric 
 acid. At this point of the proce(!ding there is a 
 tendency for the sulj)huric acid to be sucked up the 
 tube into the retort. To prevent this the retort is 
 held over a spirit lamp and heat very cautiously 
 ajiplied, care being taken that while the heat is 
 suliicient to prevent the sulphuric acid rising in the 
 tube it does not cause too violent disengagement of 
 gas. When the whole of the water has passed over 
 from the retort into the flask, and the gas is passing 
 off regularly and steadily, the temperature must be 
 raised. This is done by placing wire gauze round 
 the bottom of the retort and applying strong heat, 
 till the mixture in the retort becomes nearly white. 
 When this is so, bubbles of gas are no longer dis- 
 engaged, and the sulphuric acid begins to rise in 
 the tube. The heat must now be withdrawn and 
 the glass stopper taken out of the retort. The 
 flask is detached and the contents poured into a 
 beaker, a few drops of litmus solution (page 70) added, 
 and the non-saturated sulphuric acid measured with an 
 equivalent quantity of a standard soda solution. Thus, 
 of 100 cc. of the sulphuric acid solution 20 cc. are found 
 to be saturated, as ammonia sulphate, and as 1 cc. of 
 sulplmi'ic acid = 0'00-i25 grm. of ammonia, or 
 0'0035 grm. of nitrogen; then 5 cc. of urine contain 
 •0035 X 20 = "0700 grm. of nitrogen. Consequently 
 if 1200 cc. of urine have been passed in the 24 hours 
 
 •0700x1200 .„„ „ ., .._Q . , 
 , = lo'o gims. 01 nitrogen (258 grains). 
 
 And so with faeces, if 80 grms. represent the amount 
 of dried foeces passed in the 24 hours, of which 5 
 grms. are distilled with soda-lime, and the resulting 
 ammonia saturates 25 cc. of the sulphuric acid 
 
234 Clinical Chemistry. [Chap. v. 
 
 solution, then "0035 x 25 = -0875 grm. of nitrogen 
 for every 5 grms. of dry faeces, and consequently 
 
 = 1"6 grms. of nitrogen (24"6 grains) passed 
 
 off by the bowels in the twenty-four hours. It was by 
 this method that the late Professor Parkes showed the 
 close parallelism that existed between the entrance 
 and exit of nitrogen. Thus, in one case, with an 
 entrance of 270 grains of nitrogen, 254*04 were passed 
 off by the kidneys, and 27*74 by the bowels, making a 
 total exit of 281*78 grains. In a second case the 
 entrance amounted to 302*6 grains, and the exit 
 312*8 grains, of which 296*2' grains passed off with 
 the urine, and 16*6 by the bowels. Panke also found 
 that with an entry of 296 grains of nitrogen, 26*23 
 grains were passed by the bowels, and 281 grains by 
 the kidneys, making a total of 307*23 grains of 
 nitrogen. 
 
 The standard solution of sulphuric acid required 
 for the process is made as follows : — 12*6 grammes of 
 oil of vitriol are weighed and diluted up to a litre of 
 distilled water ; the quantitj^ of sulphuric acid in each 
 20 cc. should be determined by barium chloride 
 solution, so that each 100 cc. of the dilute acid should 
 contain 1*0 gramme of sulphuric acid, and this 
 corresponds to 0*425 gramme of ammonia, or 0*35 
 gramme of nitrogen. Consequently 1 cc. contains 
 0*00425 gramme, or '0035 gramme of nitrogen. 
 
 The sodium hydi-ate solution must be standardised 
 so that 20 cc. of it should exactly neutralise 20 cc, of 
 the dilute sulphuric acid solution. 
 
Urinary Calculi. 235 
 
 CHAPTER VI. 
 
 MORBID PRODUCTS. 
 
 152. Urinary and renal calculi. — With re- 
 gard to the origin and mode of formation of uiinary 
 calculi, it may be stated that the nuclei, except in the 
 case of foreign bodies introduced from without, are 
 formed in the kidney, where they may be retained to 
 form a renal calculus, or pass down the ureter into the 
 bladder, and so become vesical. Their increase in 
 size depends on additions made to the original nucleus 
 by the constituents of the urine, and these additions 
 may be either of the same nature as the nucleus itself, 
 or may be formed of other urinary constituents, which 
 may become subsequently in excess, or may be de- 
 posited by alterations of the reaction of the urine. In 
 considering, then, the history of any given stone, we 
 have first to ascertain the nature of the causes that 
 led to the formation of the nucleus, and then trace the 
 growth of the stone as exhibited by the chemical com- 
 position of its successive layei-s. Various views have 
 been advanced to explain the formation of calculi. 
 The ancient authors held that stone was formed in the 
 urinary organs by a kind of slime baked by the heat 
 and dryness of the parts, just as a portion of soft clay 
 may by extei'nal heat be turned into brick or 
 tile.* This view maintained until Marianus Sanctusf 
 pointed out that calculi were of two kinds, the one no 
 doubt formed by heat, but others by cold and humidity 
 as marble was formed. Paracelsus was the first who 
 
 * Hippocrates (irtpi a.ipuiv, vBariov romav, cap. ix.). 
 
 t De lapide renuni et vesica, in thesauro chirurgise, Petri UflEen- 
 bachii. Folio, p. 903. Francof. IGIO. 
 
236 Clinical Chemistry. [Chap. vi. 
 
 submitted calculous matter to chemical analysis (1530). 
 He demonstrated that it was composed of organic 
 matter or nutritive principle, an earthy principle, and 
 a volatile salt ; and he thought calculous matter was of 
 the nature of tartar, caused by the union of the nutri- 
 tive principle and the saline spirit which coagulated the 
 earthy matter. This view, with some modifications, 
 was held by Van Helmont, and the iatro chemists who 
 followed, and it ultimately resulted in the doctrine of a 
 "concreting acid," so that when Scheele in 1776 dis- 
 covered uric acid, it was regarded as being the forma- 
 tive principle of stone, and was in consequence 
 designated lithic acid. This view was proved 
 erroneous by Wollaston's discovery of calcium oxalate, 
 ammonio-magnesium phosj)hate, and calcium phosphate, 
 as constituents of some stones. These discoveries, 
 Irawever, gave too great a prominence to the chemical 
 origin of stone, and the idea gained ground that 
 urinary calculi were the result of a peculiar diathesis 
 wherein uric acid, oxalic acid, or the phosphates were 
 formed in excess in the system, and were eliminated 
 in such quantities that they were precipitated in the 
 urinary passages. The first correction of this view 
 was made by Front with regard to uric acid, and 
 Bence Jones Avith respect to phosphates, both of whom 
 showed that these substances for their precipitation 
 need not be in excess, but that they were precipitated 
 even when present in their normal quantities by 
 changes taking place in the reaction of the urine. 
 About this time Hainey published his researches on 
 molecular coalescence (§ 11, page 26), which drew 
 attention to the important part played by the 
 mucus of the urinary passages in furnishing the colloid 
 medium in which the precipitated matters were 
 moulded. In fact it was the slime of Hippocrates, 
 the " gros humeurs gluans, espais et visqueux " of 
 Ambrose Pare (1564). In all researches, therefore, 
 
Chap. VI.) Origin of Calculi. 237 
 
 into tlie origin of stone the.se tAvo branches of enquiry 
 must be taken in hand together, viz., the nature of 
 the pi'ecipitated matters and the supply of colloid 
 material. With regard to the former our knowledge 
 is now pretty definite, and the causes of their depo- 
 sition will be found related § 111, page 125, § 113, 
 pages 133 and 134. Thus we have seen that uric 
 acid and urates are deposited from highly acid urine ; 
 calcium phosphate from urine, alkaline from the fixed 
 alkalies ; ammonio-magnesium phosphate (triple phos- 
 phate) from urine, alkaline from volatile alkali derived 
 from the decomposition of urea ; and calcium oxalate 
 probably from an acid fermentation of mucus in the 
 urinary passages as well as from the calcium oxalate 
 derived from the system. With regard to the nature 
 of the colloid medium various views have been ex- 
 pressed. Thus, Dr. Owen Rees is in favour of a gouty 
 catarrh. Among the many evils arising from the 
 gouty diathesis is a tendency to this kind of action on 
 the part of mucous surfaces. Others have suggested 
 some chronic sub-inflammatory condition. Among the 
 Germans a specific catarrh [stein-bildenden catarrh) 
 has found favoui'. But if stone originated from 
 catarrhal or inflammatory conditions it would be more 
 frequent than it is, since catarrhal conditions asso- 
 ciated with deposits of urinary constituents often siib- 
 sist together without stone resulting ; for instance, in 
 nephritis, where, with abundance of tube-casts, blood 
 and epithelium poured into the urinary passages, we have 
 frequently co-mingled urates and uric acid, deposited 
 from the concentrated urine, yet stone is not recognised 
 as a clinical sequence of acute nephritis. Again, 
 calculus is not infrequently met with in persons who 
 never have given evidence at any period of having 
 suffered from catarrh, gouty or otherwise. That the 
 mucus of the urinary passages furnishes the colloid 
 medium by which the stone grows is undoubted ; but 
 
238 Clinical Chemistry. [Chap. vi. 
 
 I think in the case of the nucleus, the colloid medium 
 is furnished in some other way than the mucus of the 
 urinary passages. Some time since I suggested* that 
 instead of the calculous matter being originally 
 deposited in the pelvis of the kidney, the deposition 
 might primarily occur in the cells forming the wall of 
 the renal tubules as the result of some vital impair- 
 ment, so that the products normally eliminated by 
 them were retained and deposited instead. In support 
 of this view I would urge the fact, that, in the urine 
 of those animals who secrete uric acid in a semi-solid 
 state, it is not diiEcult to find evidence of this sub- 
 stance being contained in the cells of the renal epi- 
 thelium. Besides, the late Professor Quekett {Medical 
 Times and Gazette, 1851) gives the figure of a crystal 
 of calcium oxalate enclosed in a human renal cell. It is 
 more difficult, however, to prove that calculi are formed 
 in the tubules, since they must readily shell out and 
 pass into the pelvis of the kidney. But Prout, as the 
 result of his observations, came to the conclusion that 
 ui-ic acid was secreted by the mammillary processes of 
 the kidney, in a semi-fluid state, which afterwards 
 becomes hard, and contracts as it hardens. Sir 
 Benjamin Brodie,t in confirmation of Prout, refers to 
 the fact that in Dr. William Hunter's Museum, which 
 was formerly in Windmill Street, but which is now in 
 Glasgow, there are several preparations illustrative of 
 this point in pathology ; to wit, the formation of 
 calculi at the mammillary processes. In some of these 
 preparations " the mammillary processes have been 
 longitudinally divided, and the tubuli uriniferi are 
 seen blocked up with calculous matter ; and in one of 
 them, the development of the calculus being further 
 
 * Lancet, vol. ii., 1883; and Quain's " Dictionary of Medicine," 
 article, Calculus. 
 
 t "Lectures on Diseases of tlie Urinary Organs," 4tli edition, 
 p. 239. Longman k Co. 
 
Chap, vi.i Origin OF Calculi. 239 
 
 advanced, it is seen partly embedded in the apex 
 of tlie manimillary process and partly projecting into 
 the infundibulum." 
 
 Again, in the uric acid infarcts occurring in the 
 tubules of young infants we find these to consist of small 
 granules, spheroids, etc., an evidence that the deposi- 
 tion has taken place in the presence of a colloid ; and 
 this coUoiil, I imagine, is more likely to be a renal cell, 
 than furniahed by a gouty, or specific catarrh. Those 
 who admit the proljaljle formation of the nuclei of 
 calculi in tlie mammillary processes of the kidney 
 attribute their formation to the more concentrated 
 condition of the urine in the straight portion of the 
 tubule than in the convoluted part. The degree of 
 concentration is, however, very slight, whilst the in- 
 creased diameter of the tubule in this part of it':! 
 course, and there being less obstruction to the onward 
 flow than in the convoluted part, would more than com- 
 pensate for any increase of concentration that might 
 occur. The true explanation of the occurrence of this 
 deposit lies, I think, in the diffei-ence of the anatomi- 
 cal structure of this part of the tubule. If we examine 
 a urinary tubule, we find it composed, from the neck 
 of the capsule to the commencement of the ductus 
 papillaries, of a wall of basement membrane (tunica 
 propria) on which the epithelial cells lie ; from the 
 ductus papillaries to the apices of the pyramid the 
 tubules lose their basement membrane, so that the 
 wall is here formed of the epithelium alone, just as 
 occurs in the ducts of the sweat glands where they 
 perforate the epidermis. This portion of the tubule is 
 also less freely supplied with blood than the other 
 parts of the medulla. In the medulla the blood is 
 conveyed by long vessels, the arteriolfe rectse, which 
 collectively enter the medulla from the side of the 
 cortex. These arterioliie rectte proceed from branches 
 of the renal artery, which also give otf the ai'teria 
 
240 Clinical Chemistry. [Chap. vi. 
 
 inter-lobularis to tlie cortex. The arteriolse rectse run 
 towards the fissure -like spaces in the marginal portion 
 of the medulla betweeji the fasciculi of urinary tubules. 
 A brush of parallel vessels arises from the trunk of 
 each arteriolse rectas, and when the vessels of this 
 brush come into contact with the converging bundles 
 of the urinary tubules, they break up into capillaries 
 that form looped plexuses round the tubules ; and as, 
 on account of the progressive narrowing of the fissure, 
 one artery after another thus reaches the fasciculus of 
 the tubules, so do they successively break up into 
 capillaries. The number of the arteriolse consequently 
 diminish towards the papillae, until in the latter 
 only one or two remain, which break up into capil- 
 laries and are distributed over the papillae themselves. 
 It will thus be seen that less blood circulates through 
 this part of the kidney tubule, and we know by 
 analogy that textures possessed of feeble circulation 
 are particularly prone to undergo degenerative change 
 of some sort or other. The fact also that the base- 
 ment membrane disappears at this part of the tubule, 
 and that the wall consists alone of epithelium, may 
 also tend to produce degenerative changes in the cells 
 composing it. 
 
 A consideration of the clinical conditions under 
 which we find calculus adds some support to view I 
 have adduced. Calculous disease is most frequent 
 during the period of childhood, early youth, and old 
 age,* periods when the tissues, either from rapidity of 
 growth or general impairment of vitality, are most 
 likely to undergo atrophic and degenerative changes. 
 After the age of puberty and during the period of 
 middle life calculi are comparatively rarely met 
 with, although attacks of gravel are common. We 
 frequently find the history of a calculus associated 
 with some previous illness, in which the "vdtal powers 
 * Statistics collected by Sir Henry Thompson. 
 
ciiap. vi.i Disintegration OF Calculi. 241 
 
 ]i;i\c lioeii iiiurh oxlmiistod. Blows ou tlie loins, 
 violent strains of the back, etc., often load to thf3 
 formation of calculous matter in the kidney ; un- 
 doubtedly in some of those cases extravasation of blood 
 into the tubule may form the nucleus, but there are 
 many cases where a most careful examination of the 
 nucleus fails to prove a liajmic origin. The frequent 
 association of stone with gouty tendencies may be 
 explained by the existence of this state of impaired 
 vitality and textural dogenei-ation, and the calculous 
 deposit that occurs in the renal tubules is caused in 
 a similar manner as the deposits of sodium urate, in 
 the parts poorly supplied with blood, as the cartilages 
 of the joints and ear ; a deposit which is undoubtedly 
 due to the inability of these tissues to eliminate the 
 insoluble urate. 
 
 But of greater importance than the mode in 
 which calculi are formed is the question of their 
 disintegration, since it is upon a study of the condi- 
 tions that tend to produce this result that we can 
 hope to effect their removal from the body. Calculi 
 in the renal or urinary organs break up, or disintegrate, 
 in three ways : (1) By fracture from direct violence. Sir 
 Benjamin Brodie {op. cit. 2SG, 287) has recorded 
 instances of stones being fractured, apparently by 
 concussion against each other. To allow of this, the 
 calculous material must have been poor in organic 
 matter and consequently very brittle ; or there may 
 have been a friable layer interposed between two 
 narder ones, as in Dr. Ord's case {Path. S'oc. Trans., 
 vol. XXX., p. 319). (2) Spontaneous fracture. Dr. 
 Ord has collected several examples of calculi under- 
 going fracture, ajjparently from forces contained 
 within themselves. In two cases {Path. Soc. Trans., 
 vol. xxviii, p. 171 ; vol. xxix., p. 162) it seemed to be 
 caused by ex[)ansion of the nuclei ; in a third (vol. 
 xxxii., p. 304), the spores and mycelium of a fungus 
 
242 Clinical Chemistry. [Chap. vi. 
 
 were found mixed with the debris, and Dr. Ord thinks 
 this fungus growth was the cause of the breaking up 
 of the calculus. Mr. Pearce Gould has drawn my 
 attention to a calculus recently removed at the Middle- 
 sex Hospital, which contained, in its interior, purulent 
 fluid ; one can readily see how changes in a fluid 
 contained within any of the layers of a calculus might 
 lead to its disintegration, either fi'om disruption owing 
 to decomposition of the fluid, causing the evolution of 
 gas, and so, as it were, blowing up the calculus ; or 
 else from the drying up of the fluid and the caving in 
 of the walls surrounding the cavity. (3) Disintegration 
 hy medical means. In spite of Sir Henry Thompson's 
 statement, that he " cannot find that any patient 
 certified to have stone after sounding by a competent 
 surgeon, after a course of any solvent being again 
 sounded, or submitted to autopsy, was found free from 
 stone," considerable success attended the adminis- 
 tration of solvent remedies by the physicians of 
 the last century for the relief of vesical calculi. 
 Sir Henry Thompson seems to have overlooked the 
 cases reported, by Stephen Hales, F.R.S., and David 
 Hartley, F.R.S., of the four patients examined and 
 treated in Guy's and St. George's Hospitals by 
 surgeons of those institutions under the observation of 
 the president and censors of the Royal College of 
 Physicians with a view of determining the merit of 
 the solvent treatment.* Certainly Cheselden, Nourse, 
 and Sharp were competent surgeons, and not likely, in 
 testing what was considered a quack medicine, to have 
 omitted to state the fact if they had been able to 
 detect a stone on the subsequent sitting. As these cases 
 have been overlooked by modern writers on calculous 
 diseases, T quote them in brief in order to show the 
 success attained by this mode of treatment. 
 
 * Tracts B (No. 4) 250, in the library Royal Medical and 
 Chirurgical Society, 
 
Chap. VI.] SofMTlON OF CaLCUI.I. 243 
 
 Case I. Mr. Gardiner ;Et. Gl. Sounded by Mr. 
 Nourse, in presence of Mr. Wall, apothecary, Nov. 30, 
 1738. Stone detected. Took solvents for eight 
 months, during wliich time he passed many fragments. 
 Sounded again Sept. 14, 1739, by Mr. Sharp, in 
 the presence of Mr. Cheselden, Mr. Sainthill, Mr. 
 Belcher; no stone detected; relief from all symptoms. 
 
 Case 2. Peter Appleton, set. 67. Sounded by Mr. 
 Sharp, Guy's Hospital, July 6, 1739, in presence of 
 Dr. Pellet, President; R. C. Phys. Dr. Whittaker, 
 Censor ; and Dr. Nesbit. A stone found which was 
 considered a large one. Took solvents for five months, 
 during which time he passed much grit. Sounded 
 again Nov. 9, by Mr. Sliarp, in the presence of thirteen 
 surgeons and physicians ; no stone could be detected ; 
 relief from all symptoms. 
 
 Case 3. Heniy Norris, set. 55. Sounded at St. 
 Geoi'ge's Hospital, Aug. 17, 1739, by several surgeons. 
 Stone detected. Took medicines four months, during 
 which he voided a thick sediment. Sounded again at 
 St. George's, Dec. 14; no stone could be detected; 
 relief from all symptoms. 
 
 Case 4. William Brightly, set. 79. Sounded at 
 Guy's Hospital, Sept. 8, 1739, by Mr. Sharp and Mr. 
 Gardiner. Stone detected. Took solvents for four 
 months, voided grit freely. Sounded again at Guy's 
 Hospital by Mr. Sharp ; no stone could be found. 
 
 In addition to these well-authenticated cases, I 
 have collected some 130 cases in which the use of 
 solvent remedies was followed either by complete 
 relief or diminution of the suffering. The introduction 
 of lithotrity as an operation has rendered the use of 
 solvents unnecessary as regards the treatment of 
 vesical calculi ; but the question may be asked why, if 
 such successful results were obtained last century with 
 solvents as regards vesical calculi, why do we not 
 succeed with the same remedies in treating renn'. 
 
244 Clinical Chemistry. [Chap. vi. 
 
 calculi now % The answer is, that the conditions 
 under which renal concretions can be submitted 
 to solution are distinct from those which subsist 
 in the case of vesical concretions. "With the latter 
 we have the urinary bladder, capable of holding 
 four ounces of strongly alkaline fluid completely 
 surrounding the stone, and, moreover, easily kept 
 alkaline ; whilst, to increase the concentration of 
 fluid in the bladder, the patient was ordered to drink 
 sparingly, and to restrain, himself from passing water as 
 long as he could. With renal calculi, however, the 
 case is different. The urine in contact with the 
 calculus at any given time is only a small quantity, 
 and as this passes away directly to the bladder, it is a 
 matter of extreme difficulty to keep the urine constantly 
 alkaline. Alkaline remedies have, consequently, to be 
 given more frequently, and the aggregate amount of 
 alkali required to effect anything like a decided chemi- 
 cal action is much more than would be the case than 
 •when the whole of the alkaline urine was collected in 
 the iirinary bladder. Moreover, there is the greatest 
 difficulty in maintaining hour by hour the urine in 
 an alkaline state. A dose of alkali is speedily 
 eliminated, and though it renders the urine strongly 
 alkaline for a time, at the end of two hours the effect 
 has generally passed off, and the urine becomes acid. 
 So while the urine in the bladder may remain alka- 
 line from the first portion of the secretion, the latter 
 portions as they come from the kidney may be acid. 
 Moreover, the experiments of Bence Jones, Parkes, 
 Beneke, and myself,* have shown that the alkaline 
 bicarbonates, whilst they render the urine alka- 
 line for a time, subsequently tend to increase the 
 acidity. And it is probable the vegetable salines, 
 the citrates and tartrates, act similarly, since they are 
 reduced to the condition of bicarbonates in the blood. 
 * Lancet, Nov. 9th, 1878. 
 
Chap. VI.] Solution of Calculi. 245 
 
 At all cvonts, Dr. Bence Jonos found that although 
 five drachms of tartrate of ammonia wore taken in one 
 day the urine was not made alkaline, whilst with a 
 fixed alkali like potash this large dose was required to 
 keep the urine alkaline for a portion of the day only. 
 Not only also is there a dilliculty in getting patients to 
 take these large doses with sufiicient frequency and 
 regularity, but I doubt the projjriety of giving such 
 large doses of the alkalies for long periods of time. I 
 have found quite as much good result from the con- 
 tinued use of distilled or soft water. Dr. Murray, a 
 few years back, called attention to this mode of treat- 
 ment, and I have since employed it in all cases coming 
 under my notice, and I can fully confirm all Dr. 
 Murray said in its favour. In one case {Path. Soc. 
 Trmis., vol. xxxiii., p. 206) the calculus was passed as 
 a mere shell, much eroded, after two years' persistence 
 in the use of soft water, just at a time when the 
 question of operative px'ocedure was being entertained. 
 In cases of smaller calculi they came away more freely, 
 their surface being eroded, showing that some diminu- 
 tion in bulk had been occasioned. The action of 
 distilled water in promoting the disintcgi'ation of 
 calculi ma}' be explained by its taking up inorganic 
 matter and withdrawing it from the body ; whilst by 
 taking four pints daily of soft water instead of four 
 pints of ordinary drinking water, about 80 grains of 
 saline constituents (chiefiy lime salts) are cut off. It 
 is evident, therefore, if we diminish the supply of 
 inorganic matter, less will be withdrawn from the 
 body, so that after a time the urine will contain less 
 and less ; and it has been shown that the poorer 
 calculi are in inorganic constituents, the greater their 
 tendency is to disintegrate. Again, soft water has a 
 powerful diuretic action, increasing the urinary fiow 
 by 12 to 20 per cent, and diminishing the specific 
 gravity. Now, Mr. Rainey in his work on molecular 
 
246 Clinical Chemistry. [Chap. vi. 
 
 coalescence has shown that bodies placed in solutions 
 of diiferent density, to that in which they were formed, 
 have a tendency to undergo molecular disintegration. 
 Lastly, soft water seems to diminish the catarrh of 
 the urinary passages, and thus prevents the excessive 
 formation of mucus, which aids in the growth of the 
 calculus. This is a point that ought to be more 
 attended to than it is, for not only does the reduction 
 of the catarrh prevent any further increase in growth, 
 but it gets the urinary passages into a better state to 
 allow the passage of the stone. 
 
 Chemical examination of itrinary calculi. — 
 Notice the size and general appearance, whether in 
 section they are made up of concentric layers, or pre- 
 sent a uniform surface. A portion of the stone is 
 then broken down and reduced to powder. If the 
 stone is made up of different layerg, a portion of the 
 powder of each layer must be submitted to analysis. 
 
 Class I. Little or no residue is left when a small 
 portion of the powder is burnt on platinum foil under 
 the blow-pipe. The calculus may consist of Uric acid, 
 Xauthin, Cystin, or Hsemic elements, or is Fibrinous, 
 or composed of Urostealith. 
 
 (1) Uric acid calculi are the most common of all 
 calculi, constituting about 80 per cent, of all varieties, 
 and often attain a considerable size ; they are usually 
 smooth, and of a light yellow or reddish - brown 
 colour. The burnt powder evolves an odour of 
 prussic acid and of burnt animal matter ; the ash is 
 extremely small, and contains traces of sodium phos- 
 phate and carbonate. Dissolved in liquor potasses, 
 and reprecipitated by the addition of hydrochloric acid, 
 the characteristic crystals will be observed under the 
 microscope. Heated with nitric acid and touched with 
 ammonia the purple colour (murexide) will be produced. 
 
Chap. VI.) Analysis of Calcvi.t. 247 
 
 (2) Xanthiii cnlcitii are cxtrcinely rare ; they are 
 usually smooth, and of a oinnaiiion colour, taking a 
 polish when rubbed. They dissolve in nitric acid 
 without eft'ervoscence ; and do not yield the murexide 
 reaction with nitric acid and annnonia. To obtain 
 crystals of xanthin dissolve a little of the powder in 
 hydi'ochloric acid on a glass slide, and allow the solu- 
 tion to evaiioratc slowly. 
 
 (3) Cystin calculi are also very rare, they have a 
 smooth surface, a greenish -yellow colour, and break 
 with a crystalline fracture ; they are the softest of all 
 calculi, and for some days after their removal are com- 
 pressible. Cystin dissolves in the caustic alkalis and 
 in strong mineral acids ; on evai)orating the ammonia 
 solution cy.stin is deposited in regular hexagonal 
 tables ; on evaporating the hydrochloric solution cystin 
 crystallises in radiating needles. Boiled in a solution 
 of caustic potash with a little lead acetate, a black pre- 
 cipitate of lead sulphide is thrown down, which is 
 due to the presence of sulphur contained in the cystin. 
 
 (4) Ha'inic, fibrinous, vrosteal'dlt, Siwd incliffo concre- 
 tions clear considerably, and leave little or no ash. 
 The ha'mic concretions both microscopically and 
 chemically show that they are derivations from blood. 
 Tlie liljrinous concretions give the reaction of tibrin. 
 The urostealith concretions, which are a mixture of 
 fatty and soapy matters, mucus and withered cell 
 forms, dissolve in ether. Concretions of indigo are 
 sometimes met with. [See Dr. Ord's case, Path. 
 Soc. Trans., vol. xxix., p. 155.) The best test for 
 the presence of indigo is the reducing^ action of 
 glucose in an alkaline solution (§ 119, page 150). 
 The probable explanation of the deposit of indigo 
 in the urine will be found § 77, page 53. 
 
 Class II. A considerable residue is left when a 
 small portion of the powder is l)urnt on platinum 
 
248 ' Clinical Chemistry. [Chap. vi. 
 
 foil. The calculus may consist of Calcium phosphate, 
 Ammonio-magnesium phosphate, Calcium oxalate. Cal- 
 cium carbonate, or Urates. 
 
 (1) Calcitmi phosphate. — Calculi composed solely of 
 this substance are extremely rare ; when met with they 
 are often of considerable size. They have a white 
 chalky appearance, and their surface is very friable. 
 Most commonly calcium phosphate is mixed with, 
 ammonio-magnesium phosphate, forming the mixed or 
 fusible calculus (q.v.). The ash does not fuse (infusible) 
 under the blow-pipe, is soluble without effervescence 
 in hydrochloric acid. The acid solution gives a pre- 
 cipitate with ammonium oxalate, indicating the pre- 
 sence of lime ;- and a yellow precipitate with uranium, 
 nitrate, shows the presence of phosphoric acid. 
 
 (2) Ar)i7)ionio - 7)iagnesiuin phosphate, rare as an 
 entire concretion, but frequent as a layer or crust of 
 other calculi. Since it is formed whenever the urine 
 becomes alkaline from the presence of volatile alkali 
 (ammonia), the result of ureal decomposition set up by 
 morbid state of the urinary passages, and thus it be- 
 comes a frequent component of urinary calculi. Under 
 tbe blow-pipe the ash fuses with difficulty, and dis- 
 solves in hydrochloric acid without effervescence. The 
 acid solution, when ammonia is added in excess, throws 
 down the characteristic crystals of triple })hosphate. 
 
 (3) Fusible calculus, a mixture of calcium phos- 
 phate and triple phosphate, often with some addition 
 of calcium oxalate ; frequently attain a considerable 
 size in a short time. Under the blow-pipe fuses into 
 a glistening enamel, which adheres firmly to the pla- 
 tinum foil on which, it is fused. The powder of the 
 calculus dissolves readily in hydrochloric acid ; the acid 
 solution, on the addition of ammonium oxalate, throws 
 down a precipitate of calcium oxalate, indicating the 
 presence of lime. If this is filtered off and ammonia 
 added, crystals of triple phosphate will crystallise out. 
 
Chap. VI.] Analysis of Calculi. 249 
 
 If the calculus contains traces of calcium oxalate, the 
 ash will dissolve with etlervescence, and a portion of 
 the calculus itself will not dissolve in acetic acid. 
 
 (4) Calcium oxalate calculi are either small and 
 pale-coloured, or large, dark-coloured, with a rough, 
 irregular surface, and on section present an angular 
 structure, with in-egular, dark-coloured laminte. The 
 smaller calculi, from their size and a})pearance, are 
 termed "hemp-seed calculi;" the larger "mulberry 
 calculi." Very rarely it is deposited on other calculi in 
 a crystalline form. {See case reported by Mr. Morrant 
 Baker, Path. Soc. Travis., vol. xxv., p. 261.) Heated 
 on platinum foil, it first of all chars from the com- 
 bustion of the organic matter, and gives off an odour 
 of burnt animal matter ; finally the residue becomes 
 white, and consists of calcium carbonate, which dis- 
 solves with etlervescence on the addition, of hydro- 
 chloric acid, owing to the reduction of the oxalate to 
 a carbonate by combustion. This solution, when 
 neutralised with ammonia, throws down a precipitate 
 of calcium oxalate on the addition of oxalic acid. X 
 portion of the calculus itself is insoluble in acetic acid. 
 
 (5) Calcium carbonate calculi are rare, but when 
 met with are generally multiple, occurring in large 
 numbers, often derived from the prostate gland. They 
 ares})herical in shape, sometimes cubical or pyramidal. 
 On section they appear to be composed of concentric 
 rings, and by polarised light they sometimes display a 
 dark-looking cross. Powdered, they dissolve in hydro- 
 chloric acid with effervescence. Under the blow-pipe 
 the powder slowly fuses. 
 
 (6) Urates. — Calculi composed entirely of urates are 
 veiy rare; they are generally found mixed with uric acid. 
 They are distinguished from this l)ody by the powder 
 being soluble in hot water, which dissolves the urates, 
 leaving the uric acid. The filtrate evaporated gives 
 with nitric acid and ammonia the murexide reaction. 
 
250 Clinical Chemistry. [Chap. vi, 
 
 153. Biliary calculi vary in size from mere 
 grains to masses as large as pigeon's eggs, or even 
 larger, since stones measuring from two to two and a 
 half inches long, and one inch thick, are to be found in 
 most hospital museums. Their number is in inverse 
 proportion to their size ; the smaller they are the more 
 numerous. Some thousands of small calculi, varying 
 in size from a grain of sand to that of a small pea, are 
 often recorded as having been removed from the gall 
 bladder. The medium-sized stones are generally 
 multiple, but they are not present in such excessive 
 numbers, whilst the large stones are usually solitary. 
 It is rare for one stone to differ from its fellows, taken 
 from the same gall bladder. However numerous the cal- 
 culi may be, or variable in size, in external appeai'ance 
 and chemical composition they will be found to cor- 
 respond. Gall stones, though more or less rounded 
 form, vary considerably in shape \ thus they may be 
 cubical, pyramidal, polyhedral, etc., with the edges 
 rounded off and facetted, or their plane surfaces ren- 
 dered concave. These changes from the rounded or 
 ovoid form are brought about by mutual pressure, when 
 there are more than one calculi present in the gall 
 bladder. With solitary calculi the rounded or ovoid 
 form is generally preserved. Foliated and branched 
 concretions are rarities. In external appearance they 
 are generally smooth and slightly greasy to the touch. 
 Others have roughened, nodulated surfaces, resembling 
 in appearance lychee nuts. The colour varies from 
 a dirty white to a yellow-brown, or even deep black 
 colour. The prevailing shades, however, are brownish 
 black (sepia), deep olive-green, and russet brown. In 
 consistence they are soft, excei)t in some forms, when 
 the crust consists largely of lime salts. This portion of 
 the calculus is often unusually hai-d. On section biliary 
 calculi present a variety of appearances. They may have 
 a simple uniform structure, apparently homogeneous 
 
Chap, vi.i Gall Stones. 251 
 
 throufchout, breaking with eitlier a crystalline or 
 an earthy fracture ; these calculi are, however, com- 
 paratively rar<\ The most common forms are those 
 that present a distinct nucleus, a hody, and sometimes 
 a crust or thin rind covering,' the body. The nucleus, in 
 recent calculi, is generally homogeneous in appearance, 
 but in old and dry gall-stones it is often shrivelled and 
 fissured. It consists for the most part of inspissated 
 mucus, -with bile pigment and cholesterin ; sometimes 
 it consists almost entirely of cholestcirin. Foreign 
 ])odies often form the nuclei. Thus, round worms, 
 distoma, fragments of needles, plum stones, aggre- 
 gations of quicksilver, have all been met with in the 
 interior of biliary calculi. The body of the calculus 
 on section presents {a) an amorphous appearance of 
 brownish-yellow colour, the material being arranged in 
 concentric layers round the central nucleus, the external 
 surface having sometimes a crust or rind, but oftener 
 no distinct crust or rind can be made out. [h) From 
 the nucleus long stratified ci'ystals of cholesterin 
 radiate towards the circumference of the stone, which 
 is covered with a dense and often nodulated crust. 
 Various explanations have been offered to explain why 
 some calculi are amorphous and others crystalline. 
 Sehueppel thought that it was the mingling of 
 the bile colouring matter with the cholesterin that 
 prevented it separating in the crystalline form. 
 Wherever, then, according to this view, there is 
 much pigment, the calculi are amorphous. Dr. Ord 
 {Path. Soc. Trons., vol. xxxi., p. 141) explains it 
 thus : "When first precipitated the cholesterin is dis- 
 seminated through a bed of biliary pigment, a colloid 
 of high molecule. This not only prevents the forma- 
 tion of separate crystals, but tends to group the 
 crystalline matter into spherules. If the colloid always 
 remained a colloid, no fui-ther change would occur; but 
 the colloid pigment tends in process of time to become 
 
252 Clinical Chemistry. [Chap. vi. 
 
 crystalline, and as step by step it assumes that con- 
 dition, the two substances are segregated into two 
 zones, a central one of the more adhesive pigment, 
 an outer one o£ the polar crystal. An experiment of 
 Dr. Ord's, showing the separation of cholesterin from 
 bile pigment, after deposition in com.bination there- 
 with, may be cited in illustration of the proposition 
 advanced. A gall stone containing a great deal of 
 pigment is reduced to fine powder. Some of this is 
 mixed on a glass slip with glycerin and glacial acetic 
 acid, and the mixture is covered with thin glass. The 
 slip is then slowly heated, over a spirit flame, to 
 ebullition. When the powder is in gTcat part dis- 
 solved, the slip is transferred to the microscope. The 
 fluid is found in a state of great agitation, and filled 
 with very small yellowish spherules, which run 
 together to form large spherules of all sizes. These 
 move about the field under the influence of the 
 currents, with all sorts of amoeba-like changes of out- 
 line ; but they are perfectly homogeneous, and do not 
 afiiect polarised light. Presently they become station- 
 ary, lose their transparency, and begin to crystallise, 
 the process beginning at one point and extending 
 thence quickly over the whole mass. The crystallisa- 
 tion converts them into lozenge-like bodies, covered 
 with somewhat round or angular projections, finely 
 marked with bent parallel lines indicating imprisoned 
 acicular crystals. Very often the interior remains 
 uncrystallised, but in a state of evident tension for 
 some time. The crystals are perfectly colourless, the 
 pigment being separated from them in subcrystalluie 
 nodules of a brilliant yellowish-red, like that of hsema- 
 toidin. After a varying time, sometimes many hours, 
 the imprisoned raphides burst from their envelope, 
 and the whole mass bristles with them, star-fashion. 
 At the same time the tense interior arranges itself in 
 concentric laminae of parallel radiating crystalline 
 
Chap. VI.] J X.I LIS /S OF GaLL StoNES. 253 
 
 fibres, still coini)l(!toly separate from the pignieiit, 
 which forms alternate layers ; so that we liave befort; 
 our eyes, within a few hours, the spectacle of the 
 formation of a tiny biliary calculus. 
 
 In this experiment, however, the solution of cho- 
 lesterin and bile pigment was first heated, and it is 
 natui-al to ex})ect tliat, in cooling, the least soluble of the 
 two would separate out first, and that would be the 
 cholesterin ; but it is doubtful whether the conditions 
 for such separation exist in the body, unless the choles- 
 terin is in considerable excess. I believe the whole 
 question depends simply on the amount of mucus pre- 
 sent in solution. If this is in excess, then the choles- 
 terin separates out slowly in an amorphous form, carry- 
 ing with it the pigment. If the mucus is not abundant, 
 and the cholesterin is in excess, it is deposited rapidly 
 in a semi-crystalline state, leaving the pigment behind. 
 A chemical examination of these calculi shows that 
 after the cholestei'in has been removed by ether there 
 is very little organic residue, whilst the crust is poor 
 in pigment but rich in lime salts, which sometimes 
 assiune a rod-like spiculated form. All gall stones 
 contain cholesterin. Some, indeed, consist almost 
 entirely of this substance, these concx-etions, which 
 are not frequent, being generally met with in young- 
 children. The mixed calculi are by far the most 
 conjinon, containing a variable proportion of choles- 
 terin, from 20 to 90 per cent., mixed with bile pigment, 
 traces of a fatty acid in combination with lime (mar- 
 garate of lime; Frericlis), and sometimes a small quan- 
 tity of bile acids, and an organic matrix derived from 
 the mucus of the gall bladder. The inorganic residue 
 consists chiefly of lime salts, carbonates and phosphates, 
 traces of iron, and sometimes copper. 
 
 An analysis of gall stones is conducted as follows : 
 Separate portions of the crust, the body, and the 
 nucleus, are to be submitted for analysis. Weigh a 
 
254 Clinical Chemistry. [Chap. vi. 
 
 fragment, incinerate under the blow -pipe, "weigh 
 the ash ; the difference represents the amount of or- 
 ganic matter present ; examine for lime salts (§ 84). 
 Thoroughly exhaust another portion with ether, decant 
 off the etherial solution and evaporate ; weigh ; this gives 
 the amount of cholesterin present. Test for cholesterin : 
 by adding a drop of nitric acid, heating, and touching 
 residue with ammonia, when a reddish-brown color- 
 ation will be given ; or by evaporating with ferric 
 chloride, and touching with hydrochloric acid, when a 
 violet blue is yielded. The residue left after exhaus- 
 tion with ether is then treated with chloroform, and 
 the chloroformic solution evaporated, when a brownish 
 powder of bile pigment will be obtained (§ 140). Some 
 calculi consist almost entirely of pigment. They are 
 rare, however, are small like gravel, and have a tarry 
 blackish lustre. When broken across they appear 
 homogeneous. 
 
 154. Pancreatic calculi are of rare occurrence, 
 usually associated with an atrophied condition of the 
 gland. They are generally multiple, and are found in 
 the main and accessory duct of the organ. They are 
 oval in shape, and their surface often presents a worm- 
 eaten appearance of whitish colour, which when 
 , rubbed acquires an enamel-like lustre. When broken 
 across, the fracture presents a glistening white porce- 
 lain appearance. In some calculi I reported on for 
 the Chemical Committee of the Pathological Society 
 (Trans., vol. xxiv., p. 137) I found they consisted of 
 24 per cent, organic matter, and 76 per cent, inorganic 
 ash. The latter chiefly consisted of calcium carbonate, 
 calcium phosphate being in smaller proportions ; the 
 soluble salts, chlorides and carbonates of potash and 
 soda, being extremely small. Process of analysis : 
 Weigh a portion of the calculus, reduce it to fine 
 powder, incinerate, weigh ; the difference in weight 
 gives the amount of organic matter and water. Divide 
 
Chap. VI . 1 PaNCREA TIC Ca LCULl. 255 
 
 the ash into two portions. With one, estimate amount 
 of lime (§ 8-i), potash, and soda (§ 88). With the other, 
 dissolve a part in acetic acid, and estimate the phos- 
 phates (§ 113); and tlie other part in hot water to 
 determine the chlorides (§ 114). The carbonates are 
 deteraiined as follows : A weighed portion of the ash 
 is dissolved in water and introduced into a small flask ; 
 this flask is fitted with a bulb tube fllled with dilute 
 nitric acid, which is prevented from flowing into the 
 mixture by means of a pinchcock. The apparatus is 
 now weighed and attached to another flask containing 
 concentrated sulphuric acid, and the bulb tube pushed 
 down to nearly the bottom of the flask, the pinchcock 
 pressed and the dilute nitric acid allowed to mix with 
 the contents of the flask. When the carbonate is com- 
 pletely decomposed, the flask is placed in warm water 
 and gentle suction applied to a tube passing through a 
 perforated cork of the second flask till all the carbonic 
 acid is removed ; the apparatus is then allowed to cool 
 and is again weighed ; the loss of weight represents 
 the amount of carbonic acid ]}resent in the salt ex- 
 amined. The amount of carbonic acid thus obtained 
 is, however, somewhat in excess of that existing in the 
 form of carbonate in the concretion, since some of it 
 is derived from tlie combustion of the organic matter. 
 155. Intesfinal concretions are found chiefly 
 in the caecum and large intestines. They vary consider- 
 ably in size and composition. In colour they are yel- 
 lowish, inclining to grey or brown tints. Their nucleus 
 is usually a foreign body, a gall-stone, woody fibre, 
 fruit stone, etc. Intestinal concretions having a defi- 
 nite composition consist chiefly of ammonio-magnesium 
 phospliate, calcium pliosphate, carbonate and sulphate, 
 organic matter and fat. The analysis of these calculi 
 is to be conducted as for urinary calculi (Class II.). 
 They should, however, always be extracted with ether, 
 to see if they contain cholesterin. When cax^bonate of 
 
256 Clinical Chemistry. [Chap. vi. 
 
 magnesia has been taken habitually it may accumulate 
 and concrete in the intestines. Concretions of yellow 
 waxy appearance are sometimes passed, varying in 
 size from a pea to a filbert ; they chiefly consist of 
 fatty matter from 60 to 70 per cent., mixed with 
 earthy phosphates (lime and magnesia) and an 
 animal substance of fibrinous nature. The fatty 
 matters can be removed by ethei", and the etherial 
 solution examined to ascertain the nature of the fats 
 as directed (§ 99, page 85). The organic residue or 
 fibrinous mass will give the reaction with hydrogen 
 peroxide (§ 23) ; the earthy phosphates estimated as 
 directed (§ 113, page 136) ; the lime and magnesia as 
 directed (§§ 84, 85, pages 59, 60). Other concretions 
 ma.y consist of masses of hair, woody fibres, and husks 
 of seeds. In Lancashire and Scotland concretions 
 composed of the caryopsis and fragments of the en- 
 velopes of the oat, studded or encrusted with crystals 
 of triple phosphate, are not iincommon. Concre- 
 tions of this character are only to be detected by a 
 microscopical examination. Animals, especially the 
 herbivora, suffer much from intestinal concretions. 
 In Persia and Thibet, peculiar stones termed " bezoar" 
 are met with in a species of antelope. They contain 
 no cholesterin, and yield only little ash when burnt, 
 and seem chiefly to consist of ellagic acid, an acid 
 related to gallic acid. It is, therefore, probable that 
 these concretions are derived from a vegetable source 
 in the articles used for diet. 
 
 156. Salivary calculi are of rare occurrence in 
 man. They generally occur in Whai-ton's duct near 
 its outlet, where they may be easily recognised. More 
 rarely they are situated deep in. the main duct near 
 the gland [Path. Soc. Trans., vol. xxiv., p. 88). The 
 nucleus often consists of a splinter of wood or a frag- 
 ment of bone. They are generally of rounded oval 
 form, greyish-yellow in colour, and tuberculated on 
 
Chap. VI.] Gouty Concretions. 257 
 
 the surface. Their average composition is : Organic 
 matter and Water, 13 ; calcium carbonate, 80 ; calcium 
 ])hos2i}iate, 4; and magnesium phospliateand carbonate, 
 3 per cent. For analysis proceed as directed for 
 pancreatic calculi. 
 
 157. Proslatic concretions occasionally form 
 in the body of the prostate gland. They are of two 
 kinds, («) very small rough concretions varying in size 
 from a poppy seed to a mustard seed, extremely nume- 
 rous, of yellowish colour, occurring in the gland before 
 any extensive disorganisation takes place ; (6) larger 
 concretions, of ii'regular and porcelainous appearance, 
 generally met with when the gland is gi*eatly dis- 
 integrated. The former variety consists of calcium 
 carbonate, mixed with a little calcium phosphate ; on 
 section they exhibit a series of concentric lines. Their 
 powder ellervesces strongly on the addition of hydro- 
 chloric acid, and yields an abundance of carbonic 
 acid gas. The acid solution, with ammonium oxalate 
 added in excess, throws down a precipitate of calcium 
 oxalate, indicating the presence of lime ; whilst a few 
 drops of uranium nitrate solution when added to the 
 acid solution throws down a precipitate showing the 
 presence of phosphoric acid. The larger concretions con- 
 tain less carbonate but more phosphate of lime than 
 the smaller ones. It must not be forgotten that there is 
 always a danger of some of the smaller calculi finding 
 their way into the bladder, and thus becoming the 
 nuclei of vesical calculi. 
 
 158. Gouty concretions. Tophi.— Gouty pei-- 
 sons are subject to deposits of sodium urate encrusting 
 the surfaces of the bones, infiltrating within tendons 
 and their .sheaths, and depositing in the cartilages of 
 the ear. In the majority of cases these deposits 
 lead to marked deformities, but in others, though 
 not a trace of external deposit may be perceptible, 
 it can be demonstrated that the cartilages and other 
 
 B 
 
258 Clinical Chemistry. [Chap. vi. 
 
 structures of the joints may be infiltrated with sodium 
 urate. Indeed, Dr. Garrod insists that gouty in- 
 flammation is invariably attended with the deposition 
 of sodium urate. Certainly the deposit is never met 
 with in acute or chronic forms of rheumatism, nor 
 in rheumatoid arthritis ; but whether an attack of 
 gout invariably leads to the deposition of sodium 
 urate is a point that requires fui'ther evidence 
 before it is finally settled, though the balance of evi- 
 dence is certainly in favour that it is. The cases 
 brought forward hitherto to disprove it were not 
 examined so completely as they ought to have been, 
 and minute traces are easily overlooked. Before 
 deciding that no sodium urate is deposited, a most 
 searching investigation is required of the cartilage and 
 synovial membranes, since, when present in extremely 
 small quantities, it is likely to escape observation. 
 When first deposited the sodium urate is in a semi- 
 fluid state, but it soon becomes hardened and chalk- 
 like. On making a vertical section of cartilage 
 affected with this deposit, it will be found that it does 
 not extend very deeply, rarely exceeding two-thirds of 
 its depth. The deposit appears to the eye amorphous, 
 but on microscopic examination it is found to consist 
 of small granules mixed with crystalline needles. If 
 the cartilage be cut into thin slices and washed with 
 cold water and alcohol, and then digested in hot water, 
 the deposit is removed, and the cartilage becomes 
 transparent. The aqueous solution being evaporated, 
 crystals of sodium urate will be deposited in small 
 tufts. Evaporated with nitric acid and the residue 
 touched with ammonia, they give the purple (murexide) 
 reaction of uric acid, whilst the ash left after incinera- 
 tion with the blow-pipe gives abundant evidence of the 
 presence of soda. These deposits are said to have 
 been found in other situations besides those above 
 enumerated, as in the lungs, the bronchial tubes, the 
 
Chap, vi.j Miscellaneous Concretions. 
 
 259 
 
 meninges of the brain, and in the concretions on the 
 valves of the heart and in the atheromatous deposits 
 in the aorta. Dr. GaiTod, however, has failed to find 
 the least trace of uric acid in such situations, and 
 suggests that tabular crystals of cholesterin may have 
 been mistaken for that body. I would further suggest 
 that the chemical test, if applied, might mislead, since 
 cholesterin evaporated with niti'ic acid and touched 
 with ammonia gives a brownish-red coloration that 
 might be mistaken for the purplish red given by 
 uric acid with this test. In the gouty kidney 
 white points and streaks are to be seen upon the 
 pyramidal portion of the kidney. In these cases the 
 sodium urate is generally believed to be deposited in 
 the tubules, but Dr. Garrod thinks that it is embedded 
 in the tibrous structure itself. The microscopical 
 appearances of this condition of kidney are admirably 
 described by Dr. George Johnson, in his woi'k on 
 diseases of the kidney. 
 
 159. l^Iisccllaneous concretions. — These con- 
 sist chiefly of varying quantities of calcium carbonate 
 and phosphate, with much fatty matter, chiefly cho- 
 lesterin, fibrin, casein, gelatin, etc., and proteid bodies. 
 Such are the pulmonary concretions, deposits in mus- 
 cular tissues, nasal concretions, etc. The following are 
 a few^ of the recorded analyses giving the pei-centage 
 amount of the organic matter and calcium phosphate 
 and carbonate : 
 
 Solid 
 tiunoiir 
 
 from 
 uterus. 
 
 Ossified 
 muscle. 
 
 Coucre- 
 tion 
 from 
 brain. 
 
 Osteoid 
 
 tumour 
 
 from 
 
 lungs. 
 
 Nasal 
 concre- 
 tion. 
 
 Organic matter "j 
 
 and water j 
 
 Calcium phosphate 
 
 Calcium carbonate 
 
 36 
 
 56 
 5 
 
 58 
 
 32-09 
 S-GG 
 
 22-46 
 
 60-32 
 
 17-21 
 
 38-89 
 
 53-33 
 
 7-04 
 
 5 
 
 90 
 
 In a concretion taken from the brain of a horse, 
 
26o Clinical Chemistry. [Chap. vi. 
 
 Lassaigne found 58 parts of cholesterin, 39 "5 proteid 
 matter, and 2-5 of calcium phosphate (Simon). 
 
 160. Products of deg'encration. — These are 
 generally divided into two classes. Those in which 
 there is a direct metaTnorjylwsis of the proteid elements 
 of a tissue, and which is generally followed by the 
 destruction of the histological elements, and the soften- 
 ing of the intercellular substance, so that the com- 
 position and structure of the tissue may be completely 
 altered. And those in which there is no conversion 
 of the pi'oteid elements themselves, into a material of 
 another kind, but the new substance is introduced 
 from without by the blood by a process of infiltration. 
 Here the cell elements and intercellular substance are 
 not softened or destroyed to any great extent, and even 
 then it is due to secondary metamorphosis produced 
 by the infiltration, as the fatty changes that are 
 associated with lardaceous infiltration. 1. Fatty de- 
 generation may occur either as an infiltration or a 
 metamorphosis, but no decided line of demarcation 
 can be often made between them, since the same 
 cause may be in action at the same time, both within 
 and without the tissues ; and also, the deposit of fat, 
 having accumulated, may, in consequence of the 
 pressure it occasions, lead to fatty metamorphosis as 
 well In fatty infiltration, when the process is dis- 
 tinct, the fat is deposited in oily drops within the cells. 
 These at first are small and distinct, but as the process 
 proceeds they accumulate and fill the cell, obscuring 
 the muscles and protoplasm. But these remain un- 
 altered, so that if the fat is removed they may be 
 restored to their original condition. Fatty infiltration 
 occurs chiefly in the voluntary muscles, which have 
 been disused, as in paralysis, joint diseases, lead palsy, 
 etc. ; in the muscular tissue of the heart, and espe- 
 cially in the liver. In this latter instance it is im- 
 portant to distinguish it from the acute fatty changes 
 
Chap. VI. I Fattv Dr.GE.\'ERArioy. 261 
 
 that are brought about by the action of certain poisons, 
 etc. In fatty liver, clue to infiltration, the organ ia 
 increased in size, the surface is smooth, and the edges 
 rounded. The section pi-esents an opaque ycllowish- 
 wliite colour, in early stages only aflecting the portal 
 area of the lobules, but gradually extending to the 
 whole lobule, leaving only a reddish point in the 
 centre, at the origin of the hepatic vein. Fatty in- 
 filtration is a chronic process. It may be induced by 
 excessive use of fatty food and alcohol, and is the 
 frequent result of chronic wasting diseases, in which tlie 
 oxvgenating power of the blood is diminished. In acute 
 fatty degeneration of the liver the organ is diminished 
 in bulk, the surface is wrinkled, and the edge sharp. 
 On section it presents a yellowish-red colour-, which 
 may be uniform throughout, or else mixed with patches 
 of brick-red (Zenker's patches). The lobules have 
 entirely disappeared, and the cells consist only of fat 
 granules and debris. The process is acute. It is met 
 with in the disease known as acute yellow atrophy, in 
 phosphorus poisoning, after the injection of the bile 
 acids, and in some few instances it has been found in 
 patients dying of acute diabetic coma. Fatty infiltra- 
 tion is brought about by excess of fat in the blood ; this 
 may be simply as a consequence of general obesity, or 
 from defective oxydation, which accounts for the fatty 
 changes which are associated with chronic pulmonary 
 disease, especially phthisis. Fatty degeneration diftcrs 
 from the preceding, in that the fat is not derived 
 directly from the blood, but by retrograde changes 
 taking place in the proteid constituents of the tissues 
 themselves. Extremely minute granules of dark colour 
 of strong refractive power, and very soluble in ether, 
 first ditluse through the protoplasm. As the process 
 continues, the nucleus is invaded and the cell wall 
 disappears. The granules at first are more or less 
 coherent, forming rounded masses (corpuscles of 
 
262 Clinical Chemistry. [Chap. vi. 
 
 Gluge) ; but after a time these break down and the 
 Efranules are distributed through the tissue. As a 
 result of fatty degeneration the tissue may be entirely 
 destroyed, or the fatty product may be absorbed, or 
 it may undergo further changes and become caseous. 
 Fatty degeneration may attack any tissue or organ. 
 In the arteries and capillaries, as a primary con- 
 dition, fatty degeneration is a senile change ; but 
 it is also secondary to inflammatory conditions of 
 the vessels, in which the deposit of fat is preceded 
 by a cellular infiltration of the subendothelial con- 
 nective tissue. Fatty degeneration of the heai't 
 may be diffused or localised. The former may occur 
 in the course of those diseases in which oxydation is 
 reduced to a minimum, as in ansemia. Dr. Green 
 (Trans. Clin. Society, vol. vui., 1875) instances a case 
 of acute fatty degeneration of the heart, induced 
 by profuse loss of blood during the menstrual period 
 and inability to take food. In a minor degree fatty 
 degeneration of heart occurs in most pyrexial con- 
 ditions. Localised fatty degeneration of the heart 
 is generally the result of disease or obstruction of 
 the coronary arteries, or the efi"ect of pericardial in- 
 flammation. Fatty degeneration of the brain may 
 be either acute or chronic. In the former it is gene- 
 rally due to sudden cutting off" of the blood supply, 
 as for instance by embolism of the middle cerebral 
 artery. In chronic softening, the supply of blood is 
 gradually diminished or slowly cut off, as occurs 
 when the vessels are diseased. In fatty degeneration 
 of the brain a considerable amount of glycerin-phos- 
 phoric acid is formed among the products of dis- 
 integration, occasioned by the breaking up of the 
 phosphorised fats, lecithin, etc. Acute fatty degenera- 
 tion of the liver has been already alluded to. The epi- 
 thelium of the kidney undergoes fatty changes after at- 
 tacks of inflammation, as in acute and chronic nephritis, 
 
Chap. VI.] Fatty Degeneration. 263 
 
 and also in acute yellow atrophy, phosphorus and sul- 
 phuric acid poisoning, and in some cases of diabetes. 
 More fat than ordinary is found in the epithelium of 
 persons dying from chronic wasting diseases. In order 
 to investigate the nature and degree of the fatty 
 changes in any given tissue we first determine the 
 aniDunt of fatty matter present, the neutral fats, the 
 cholesterin and lecithin, and then make a separate 
 estimation of the neutral fats to ascertain the jiro- 
 portionate amounts of solid and oily fat. For the first 
 determination, a weighed portion of the tissue, finely 
 divided, is to be dried till it ceases to lose weight. It 
 is then to be reduced to powder, and boiled with ether 
 for some hours. For this purpose Drechsel's fat ex- 
 hauster is undoubtedly the best form of apparatus, but 
 when not obtainable the following method can be satis- 
 factorily emi)loyed. The finely-powdered tissue is 
 introduced into a glass flask and half filled with 
 absolute ether. The mouth of the flask is then fitted 
 with a perforated cork, through which a fine glass 
 tube, about two feet long, open at both ends, is 
 introduced, the lower end of which should only be 
 allowed to project just below the cork into the flask. 
 The apparatus is suspended by means of a support- 
 stand over a porcelain basin, so that about one-third 
 of the flask is submerged, and filled with hot water 
 about twenty degrees below boiling point. Over the 
 upper third of the flask, and about half way up the 
 tube, wrap a cloth dipped in cold water, as cold as 
 possible. This prevents the too rapid evaporation of 
 the ether, a considerable portion of which condenses 
 and falls back into the flask. The temperature of the 
 water in the basin is to be maintained by the constant 
 addition of fresh supplies, as it is advisable not to 
 bring a flame near the flask containing the ether. 
 After the ether has boiled some considerable time, 
 the cork with the tube is withdrawn, and the etherial 
 
264 Clinical Chemistry. [Chap. vi 
 
 solution, whilst stUl warm, is poured into a weighed 
 platinum dish and evapox'ated. In order to remove all 
 traces of fatty matter from the flask, it should be rinsed 
 with a little absolute ether, and the rinsings added to 
 the solution in the platinum dish. This is then to be 
 weighed, and the increase of the weight gives the 
 total amount of fat. In order to estimate the 
 neutral fats, cholesterin and lecithin, separately, pro- 
 ceed as directed § 99, page 85. If it is desired to 
 ascertain the proportion of solid fats to the oily, it is 
 necessary to dissolve the fatty residue thoroughly 
 with boiling alcohol, and filter. Boil the filtrate with 
 a solution of potassium hydrate, which saponifies the 
 fatty matter. The mixture is then evaporated, and 
 the dry residue dissolved in water, which is acidulated 
 with a little hydrochloric acid. On cooling, the 
 stearic, palmitic, and oleic acids will be deposited. 
 These ai-e to be dissolved in boiling alcohol, and some 
 alcohoHc solution of lead acetate added. The preci- 
 pitate, which consists of stearate, palmitate, and 
 oleate of lead, is removed by filtration. The precipi- 
 tate is treated with hot ether (a), which removes the 
 oleate of lead, whilst the filtrate (6) contains the 
 stearate and palmitate. Both the filtrate h and the 
 etherial solution a are to be respectively treated 
 with hydrochloric acid, and the mixture warmed ; the 
 lead is then to be removed by sulphydric acid, and 
 the precipitate removed by filtration. The clear fil- 
 trates are to be concentrated, and then shaken with 
 ether, and the etherial solution allowed to evaporate, 
 when from a oleic acid will be deposited, and from 6 
 a mixture of stearic and palmitic acids (the solid fatty 
 acids) will crystallise out. 
 
 (2) Lardaceous degeneration, or, as it was formerly 
 termed, amyloid degeneration, from its supposed rela- 
 tion to starch and cellulose. The morbid material is 
 deposited in the first instance in the small arteries 
 
Chap. VI.] LaRDACEOUS DeGKNKKATION. 265 
 
 and capillaries, cliielly of the liver, kidneys, spleen, 
 and intestines, though all organs and tissues may 
 be invaded. The cells of the intirna are the first to 
 be infiltrated ; thence it spreads to the muscular wall 
 of the vessel, and from thence it passes to the cells 
 and intercellular substance, till the whole organ or 
 tissue is involved. It is still a question among 
 pathologists whether lardaceous disease is a true 
 degeneration (that is, a chemical and structural change 
 in living tissues), or whether it is an infiltration among 
 the tissues of a morl)id material derived from the 
 blood. On this question, the histologists generally 
 support the view that it is an infiltration, the patho- 
 logical chemist that it is a true degeneration of tissue. 
 When first discovered, it was thought to be analogous 
 to starchy matter, and was named amyloid ; but it was 
 soon recognised that it was a definite nitrogenous 
 body, and related to the proteid group, and the term 
 hirdacein was ajiplied to it, to express the waxy or 
 bacony appearance given to tissues affected by it. 
 With regard to the nature of this substance various 
 views have been expressed. Dr. Dickinson regards it 
 as de-alkalised fibrin ; since he has found the tissues in- 
 volved by it remarkably deficient in potash, and has 
 prepared it artificially, by digesting fibrin in dilute 
 hydrochloric acid, a substance which gives one of the 
 reactions supposed to be characteristic of lardacein. 
 In objection to Dr. Dickinson's views, it may be urged 
 that, by digesting fibrin in dilute hydrochloric acid, 
 syntonin, and not lardacein, is formed ; whilst the 
 reaction with iodine, as I showed at the Pathological 
 Society {Trans., vol. xxx., p. 536), is not distinctive 
 of lardacein, but may be given equally with dry fibrin, 
 with syntonin, and with casein. This is important, 
 since the red colour, being developed equally with 
 alkali albumin (casein) as with acid albumin (syn- 
 tonin), shows that the reaction is not caused by the 
 
266 Clinical Chemistry. [Chap. vi. 
 
 removal of an alkali. With regard to the deficiency 
 of potash existing in the affected tissues, that may be 
 accounted for by the great increase of fat found in 
 them ; and we know that tissues that have undergone 
 fatty degeneration become poorer in saline constituents. 
 The view I am inclined to adopt is, that lardacein is 
 a mixture of a proteicl with a fatty body, of which we 
 have a physiological example in vitellin, and which 
 lloppe Seyler considers to be a mixture of globulin 
 and lecithin. Lardacein may be separated from the 
 tissues by Kiihne's process. The organ is finely 
 minced, and extracted repeatedly with cold water, and 
 subsequently with dilute alcohol, till the fragments be- 
 come colourless. They are then digested with artificial 
 gastric juice. This has no action on lardacein, but 
 dissolves all the other proteids, leaving the lardacein 
 almost pure, with the exception of small quantities of 
 elastic tissue and mucin. Lardacein thus obtained 
 is soluble in dilute ammonia, from which it can be 
 precipitated by dilute acids. It is insoluble in water, 
 and does not perceptibly swell in solutions of sodium 
 chloride. Strong hydrochloric acid converts it into 
 acid albumin, and caustic alkalies into alkali albumin. 
 Touched with an aqueous solution of iodine, it 
 acquires a brown-mahogany colour, whilst methyl 
 aniline gives a rosy-red. Formerly, the blue colour 
 produced by the joint action of iodine and sulphuric 
 acid when poured on it was relied on as a test ; but 
 this blue coloration was shown by Dr. John Williams 
 {Path. Soc. Trans., vol. xxvii., p. 322) could be 
 caused by the admixture of iodine and sulphuric acid 
 alone, without the intervention of any other sub- 
 stance. 
 
 Hyaline degeneration. — At the debate on larda- 
 ceous disease at the Pathological Society, 1879, Dr. 
 Stephen Mackenzie, with reference to the influence of 
 fever in producing the disease, called attention to a 
 
Chap. VI.] Hyaline Degeneration. 267 
 
 cliange in the blood-vessels that ocairred in certain 
 diseases with blood alterations. He had fomid it in 
 the arteries of the spleen in nearly all cases of pyaemia, 
 in some cases of djal)etes, in a case of angina Ludo- 
 vici. Dr. Klein had first described the change in 
 typhoid and scarlet fevers. In most cases the change 
 was confined to the intiina, but in some it involved 
 the museularis. It consisted in a hyaline transforma- 
 tion, which did not give a characteristic I'eaction with 
 iodine, but stained slightly with methyl aniline. Dr. 
 Mackenzie did not regard the change as lardaceous, 
 but thought an examination into the nature of the 
 change might throw some light upon that disease. In 
 commenting on Dr. Mackenzie's remarks, I suggested 
 that the difference between hyaline and waxy dege- 
 neration might be only one of degree, the hyaline 
 being the first step in the degenerative process. A 
 microscopic examination of the hyaline substance 
 shows that, at first, it consists of granules of an albu- 
 minous nature, which are insoluble in ether ; but, in a 
 more advanced stage, the granules are distinctly fatty 
 and soluljle iii ether. From this, it would appear 
 that the change is connected with fatty degeneration. 
 It may be, therefore, that hyaline changes are the 
 first step in a process which, if acute, leads to fatty 
 degeneration, if chronic, to waxy or lardaceous 
 disease. 
 
 The amyloid bodies, corpora aviylacea of Kolliker 
 and Purkinje, are rounded oval bodies, varying in 
 size from extremely minute granules, which refract 
 light strongly, to bodies about one or two lines in 
 diameter, formed by the conglomeration of smaller 
 granules, apparently in a succession of concentric 
 layers. They are most frequently found in the bodies 
 of aged persons, chiefly affecting the prostate, the 
 ependyma of the ventricles, the fornix, the choroid 
 plexus, the retina, and spinal cord. They are apt to 
 
268 Clinical Chemistry. [Chap. vi. 
 
 become calcified, and in this form, when met with in 
 the nerve-centres, constitute the so-called "brain 
 sand." The corpora amylacea usually stain a deep blue 
 with aqueous solution of iodine. Sometimes a drop 
 of sulphuric acid is required to develop the reaction ; 
 occasionally, however, the iodine gives a greenish or 
 brownish tint, owing to the admixture of nitrogenous 
 matters. These bodies undoubtedly belong to the 
 amylaceous, or starchy, group, and seem to resemble 
 cellulose in their general characters. They are not to 
 be confounded with lardacein, which was unfortunately 
 termed amyloid substance when first investigated, 
 from a misconception of its real nature. 
 
 (3) Mucoid and colloid degeneration. — These two 
 forms are often associated together, and at all times it 
 is difficult to draw a rigid distinction between them. 
 In mucoid degeneration the intercellular substance is 
 chiefly affected, in colloid degeneration the cells. In 
 the foi'mer there is an increase of mucin in the con- 
 nective tissue elements, in the latter the gelatinous 
 constituents have apparently undergone changes, and 
 seem to be converted into collagen, and perhaps into 
 semi-glutin and hemi-collin. Mucin is found normally 
 in the adult in small amount in all connective tissues 
 proper; in the embryonic comiective tissue it exists in 
 much larger quantities, the umbilical cord of foetus 
 yielding it to a gi-eat extent. It is also derived from 
 the secretion exuded by epithelial cells (mucus), and 
 can be obtained in sufficient quantity for examination 
 from the saliva (§ 131, page 175) and bile (§ 139, 
 page 198). In normal urine it is present in small 
 quantities, which is much increased in catarrhal 
 conditions of the renal and urinary organs. Mucin is 
 soluble in alkaline solutions, from which it is pre- 
 cipitated by acetic acid. Mucin is not digested by 
 gasti-ic juice, but is by the pancreatic ferment. It is 
 not precipitated by potassium ferrocyanide with 
 
Chap. VI.] Mucoid Degeneration. 269 
 
 acetic acid, nor by tannic acid. Solutions of mucin 
 with alkaline copper solutions prevents the precipita- 
 tions of cupric hydrate, and no reduction takes place 
 on boiling. Collagen is the name given to a substance 
 obtained from the white fibres of connective tissue, 
 and of which they are principally composed. It can 
 be obtained toleral)ly pure by digesting finely sliced 
 tendon in water for some days. Then filter off precipi- 
 tate, and digest precipitate for some days in dilute 
 baryta water ; filter*, and wash the insoluble residue 
 thorougldy in water, then with dilute acetic acid, and 
 again with water. Hofmeister has shown that when 
 gelatin is heated for some tiuie at 130" 0. it loses 
 water and becomes converted into a substance 
 resembling gelatin ; and also when collagen is boiled 
 for more than twenty-four hours a further change 
 occurs, the collagen taking up water and becoming 
 converted into two peptone-like bodies, to which the 
 names semi-glutin and hemi-glutin have been given. 
 Hofmeister represents the changes by the following 
 equations : 
 
 Gelatin. Collagen. 
 
 ^10:i-"-161-'-^ 31^39 ~ xlvO = ^-^i02tl-i49JN3iU38 j 
 
 and 
 
 Collagen. Semi-glutin. Hemi-glutin. 
 
 C.02H149N31O3, -f 3H,0 = C^H^N,A2 + C,,H™N,,0„. 
 
 Professor Gamgee * states, that whilst mucin is un- 
 questionably a product of the difierentiation of the 
 protoplasm of certain animal cells, and is obviously 
 derived from the proteids, it is conceivable that it 
 may result also from a decomposition in which 
 collagen and mucin originate. What the nature of 
 the decomposition may be is, however, quite unknown. 
 
 * " Physioloigcal Chemistry of the Animal Body,'' p. 259. 
 Macmillan. 
 
270 Clinical Chemistry. [Chap. vi. 
 
 A further study of tlie subject is mucli to be desired, 
 as likely to throw considerable light on the pathology 
 of this degenerative process, especially with regard to 
 the chemistry of the contents of the ovarian cysts. 
 Professor Ganagee's account of these bodies is the best 
 summary extant of the work that has been done in this 
 direction. Still, there must be further investigation 
 in the physiological laboratory before the results can 
 be made available for clinical purposes. Anybody 
 taking up the subject from its present standpoint 
 would find a field for original research likely to 
 yield important results. At present, clinically, we 
 distinguish between mucoid and colloid degeneration 
 by the fact that in the former case the fluids are 
 precipitated by acetic acid ; in the latter, not. Mucoid 
 degeneration is by no means common, and seems to 
 imply a retrograde metamorphosis of the connective 
 tissue elements to their embryonic state. It occurs 
 occasionally in the intervertebral and costal cartilages 
 of old people ; it sometimes attacks the bones and 
 serous membranes. When localised, the softened 
 part surrounded by the firmer normal tissue gives 
 rise to a cyst-like formation. In an important com- 
 munication to the Royal Medical and Chirurgical 
 Society (Trans., vol. Ixi., p. 57) Dr. W. M. Ord, 
 describing the " cretinoid affection '"' occasionally 
 observed in middle-aged women, proposed that the 
 term myxoidemoj should be applied to express the 
 essential condition observable in that affection. That 
 condition relates to the jelly-like swelling of the 
 connective tissue, chiefly, if not entirely, consisting of 
 an overgrowth of the mucus-yielding cement by which 
 the fibrils of the white element are held together. In 
 one of Dr. Ord's cases the amount of mucin obtained 
 was more than a fiftieth of the quantity obtained from 
 the skin of non-oedematous bodies. The method 
 employed by Dr. Oranstoun Charles, who made the 
 
Chap. VI.) Mucoid Degeneration. 271 
 
 cheinifal analysis for Dr. Orel, is given here, as it 
 may be suitably employed for similar investiga- 
 tions. The skin of both feet was cut into pieces, 
 and divided into three nearly equal portions, «, &, 
 and 7. («) was digested with water for several 
 days ; the filtrate from this was treated with an 
 excess of acetic acid, let stand some hours, the pre- 
 cij^itate separated on a filter and washed first with 
 water acidified with acetic acid, and then with pure 
 water. This washed precipitate was next left for 
 twenty-four hours in lime-water, the solution filtei*ed, 
 and the precipitate again thrown down by excess of 
 acetic acid. To purify the precipitate thus obtained 
 it was washed successively with acidified water, pure 
 water, alcohol, and ether, and then di'ied over a water- 
 bath. The process is that employed by Eichwald for 
 the separation of mucin from Helix pomatla and from 
 tendons {Ann. ChejM. PJtarm,., Bd. 134, s. 177). 
 (ys) was left in metliylated spirits for three days, in 
 lime-water for two days, then filtered, and to the 
 filtrate acetic acid added in excess. Tlie precipitate 
 was separated and purified as in a. (7) was digested at 
 once with dilute baryta water, the dissolved mucin 
 precipitated by acetic acid, and pui'ified as before. 
 The body obtained by the above three methods was 
 sensibly the same in each case in properties and in 
 appearance, and nearly eq ual in amount ; it corre- 
 sponded in its reactions to the mucin of Scherer, 
 Eichwald, and Staedeler. Mucoid degeneration also 
 affects new formations ; thus, enchondromatous, lijDO- 
 niatous, and sarcomatous tumoui's may undergo 
 mucoid transformation, and may become wholly or 
 partially converted into myxomata. In colloid de- 
 generation the process commences appai-ently in cells, 
 and not, as in mucoid degeneration, between the white 
 fibres of the connective tissue element. The cells 
 become filled with small masses of jelly-like material. 
 
2)2 Clinical Chemistry. [Chap. vi. 
 
 which pushes aside the nucleus, and at length destroys 
 the cell ; after a time the intercellular substance 
 atrophies and softens. In many cases a true mucoid 
 degeneration of the intercellular substance seems to 
 follow the colloid infiltration of the cells. This gives 
 additional weight to Professor Gamgee's supposition 
 that mucin and collagen originate from a decom- 
 position common to both. 
 
 (4) Calcareous degeneration, or the infiltration of 
 the tissues with calcareous particles. May be either 
 general, as the result of an accumulation of cal- 
 careous salts in the blood — for instance, as in osteo- 
 malacia, where the earthy salts are removed from 
 the bone, and are often in part deposited in other 
 tissues, the lungs, stomach, or intestines. Or the in- 
 filtration may be local, due to changes in the tissue 
 itself following some impairment of their nutrition ; 
 or as a consequence of a retardation or diminution of 
 the amount of blood flowing through them, as I have 
 e]ideavoured to show, may be one of the causes lead- 
 ing to calculous deposit in the tubules of the kidney 
 (page 240). The cause of calcareous deposit in 
 tissues has been explained to arise from the stag- 
 nation of the nutritive fluids, owing to which the 
 free carbonic acid which holds the earthy salts in 
 solution are precipitated, and, the circulation through 
 the part being retarded^ these insoluble elements are 
 only partially removed, and so become deposited. The 
 ossification of arteries proceeds from this cause. Cal- 
 careous deposits consist chiefly of calcium carbonate, 
 calcium phosphate, magnesium phosphate, traces of 
 soluble salts, and generally fatty matters and choles- 
 terin. For their chemical examination, exhaust 
 thoroughly with ether, to remove fatty matters, and 
 proceed to estimate the earthy matters according to 
 the directions given for the analysis of urinary calculi, 
 Class II. (§ 152, page 248). 
 
Chap. VI.J Pus. 273 
 
 161. Iflorbid exudations. — (1) Pus is a patho- 
 logical fluid, and consists essentially of a liquid 
 portion, " liquor puris," wliich is exuded lic^uor san- 
 guinis, and wliitt^ cor))uscles, or leucocytes, which 
 cannot bo distinguished from the white corj)UScles of 
 the blood. The pus corpuscles can be separated from 
 the liquor puris by tlie addition of a 10 per cent, 
 solution of sodium chloride, and the precipitated 
 mass removed by filtration, and thoroughly washed 
 with the same solution till quite free from serum. 
 The pus corpuscles are spherical, irregular bodies, 
 al)out y'sVtt^^^ ^<^ 3 /o o tli of an inch, or 8;^ to 10/^ in 
 diameter, containing a number of granules and one 
 or more nuclei. When treated with dilute acetic acid, 
 they swell up, and become more transparent, and the 
 nuclei more distinct. Treated with ammonia or 
 potash solutions, pus becomes tenacious and jelly-like. 
 This character distinguishes it from mucus, which 
 becomes less tenacious and more fluid on the addition 
 of these solutions. According to Miescher, the nuclei 
 of the pus corpuscles contain a definite organic body, 
 containing phosphorus, which he calls nuclein. This 
 substance, he holds, can be obtained from all cells 
 where nuclei exist. It is, however, doubtful whether 
 it is a definite compound, since the results obtained by 
 analysis by different obseiwers vary considerably. It 
 is more probable that it is an ordinary proteid sub- 
 stance, combined with lecithin or other phosphorised 
 bodies, in varying propoi-tions. Eichwald has also found 
 peptone-like bodies in purulent fluids. The amount of 
 water and solids present in pus varies, of course, with 
 the nature of the pus. Thus, in ichorous, muco, or sero- 
 pus, the solids are diminished. The following is an 
 analysis of laudable pus, the result of acute inflamma- 
 tion : Water 87, Solids 13, in 100 ; proteids 8 -5, fatty 
 matters 3'0, extractives 0'7, inorganic residue 0-8. 
 The proteids are sero-albumin and paraglobulin. The 
 S 
 
274 Clinical Chemistry. [Chap. vi. 
 
 fatty matters consist of neutral fats, cholesterin, and 
 a body yielding glycerin phosphoric acid, probably 
 lecithin, but some consider it to be protagon. The 
 extractives contain traces of urea and glucose, some- 
 times leucin and tyrosin. A blue colour is often 
 noticed on the dry bandages and linen which have 
 been in contact with pus ; this is due to pyo-cyanin. 
 This substance can be obtained in a crystalline form 
 by soaking the stained linen in water, containing a 
 few drops of ammonia, for some hours, and then 
 filtering ofi" and evaporating the green liquid. The 
 concentrated filtrate is then agitated with chloroform, 
 and the chloroform solution removed and treated with 
 very dilute sulphuric acid, and the mixture allowed to 
 stand for some time. At length a red aqueous layer 
 separates, which is removed and treated with caustic 
 baryta till the solution becomes blue ; filter, and 
 agitate the filtrate with chloroform ; remove the 
 chloroform :"'*^jt'on, and allow it to evaporate spon- 
 taneously, when pyo-cyanin will crystallise out in 
 bluish-coloured needles or rectangular Hakes. The 
 crystals are soluble in water and chloroform, insoluble 
 in ether. Acids turn their solutions red, but alkalies 
 restore the blue colour ; chlorine decolorises both 
 solutions. The researches of Liicke and Fitz seem to 
 prove that pyo-cyanin is generated by a bacillus, 
 which, according to the latter observer, has the power 
 of decomposing glycerin, in the presence of calcium 
 cai-bonate, with the formation of carbonic acid, butyric 
 acid, and hydrogen. It is probably the same bacillus 
 that sometimes gives milk its blue colour. 
 
 From the chloroformic solution, after the removal 
 of the pyo-cyanin, minute yellow crystals of pyo- 
 xanthin can be obtained by evaporation. They are 
 coloured red by acids, and violet by alkalies. 
 Gelatin and chondrin are said to have been found 
 in pus, but their existence as such is doubtful. 
 
Chap. VI.] Dropsical Fluids. 275 
 
 Perhaps the peptone-like boclias described by Eichwald 
 may be related to senii-glutin and henii-glutin (page 269). 
 The inorganic residue consists chieily of soluble salts 
 of the alkaline chlorides, nio.stly as sodium chloride. 
 The earthy salts in pus derived from the soft tissues 
 are not abundant; but iii pus derived from the 
 neighbourhood of diseased bone, it may contain as 
 much as 2-5 per cent. In making an analysis of pus, 
 the paraglobulin is first precijjitated by magnesium 
 sulphate, and then the serum all)uniin coagulated by 
 heat (§ 98, page 84). The liquid is then to be agi- 
 tated with ether, to obtain the fatty matters (§ 99, 
 page 85) ; and then the extractives are to be separated 
 by the methods described for Urea (§ 100, page 86), 
 Glucose (§ 100, page 88), Leucin (§ 169, page 126). 
 A fresh portion of pus is then incinerated, and the 
 bases and acids estimated according to directions at 
 § 101, page 93. The specific gravity is taken with 
 the specific gravity bottle (§ 92, piee^66), and the 
 reaction determined as directed § 9o,\^agc 67. 
 
 (2) Dropsical flidds. — Whenever the balance be- 
 tween the two processes, transfusion of the nutritive 
 plasma from the blood-vessels and its re-absoi-ption by 
 the lymphatics, is disturbed, the quantity of paren- 
 chymatous fluid, which is always present in small 
 quantity in the tissues, becomes increased. This dis- 
 turbance of pressure of the fluid in the blood-vessels 
 and that in the parenchyma may result from general or 
 local conditions. In general dropsy, such as we find 
 in certain diseases of the kidnej-, the condition de- 
 pends on hydrtemia, especially in those forms where 
 the amount of water passing ofi" through the kidneys 
 is lessened. Thus, general dropsy is an important 
 clinical symptom, distinguishing acute tubal nephritis, 
 and the large white kidney from the gi-anular and 
 the albuminoid kidney, in both of which latter, large 
 quantities of dilute urine are passed. In general, the 
 
276 Clinical Chemistry. [Chap. vi. 
 
 dropsy of kidney disease depends on tlie diminished 
 action of the kidneys, so that the water ingested 
 being the same, its exit is lessened ; hence the 
 volume of blood being increased, the arterial pres- 
 sure is augmented, and the serum passes into the 
 tissues in consequence of the increased pressure, 
 whilst its diluted condition perhaps renders it more 
 easy. In this way the whole of the tissues of the 
 body become more or less waterlogged. When the 
 dropsical effusion is localised, as in ascites, the exuda- 
 tion of serum depends oil mechanical congestion due 
 to venous obstruction, and the increased pressure 
 takes place in the veins, and thus lessens absorption 
 by the lymphatics and veins. In the dropsy of heart 
 disease both forms are present. In diseases of the 
 mitral and tricuspid valves, which lead to dilatation of 
 the right side of the heart, obstruction of the venous 
 circulation occurs, and increased pressure in the veins, 
 which is at first most noticeable in those farthest 
 from the centre of circulation, and which from their 
 position (the lower extremities) allow the blood more 
 readily to stagnate in them. But diseases affecting 
 the right side of the heart also induce dropsy by 
 increasing the amount of water in the blood, since 
 their tendency is to diminish the flow of blood 
 through the kidney, and thus to diminish the 
 quantity of urine secreted. In disease of the aortic 
 valves, so long as compensatory hypertrophy is 
 maintained dropsy does not occur ; but so soon as 
 the left ventricle fails, the rapidity of the circulation 
 through the kidneys falls, and the quantity of urine 
 excreted diminishes, so that the quantity of water 
 inci^eases in the blood, and the condition of hydrsemia 
 is induced. It will be thus seen that dropsical fluids 
 are blood serum more or less diluted with water. 
 This is an important point to remember; for if on 
 tapping a patient we find the amount of solids in the 
 
Chap. VI.] DkO/'S/CAL FlUIDS. 277 
 
 fluids witlidnnvu in excess of tliose noniially present, 
 wo may be sure tliafc tlie fluitl is not au ordinary 
 dropsical ctiusion, and contains other matters beside.s 
 .blood serum. The specific gravity of a dropsical fluid 
 ranges from 1"005 to 1'022, according to the amount 
 of water present. The amount of jirotcids contained 
 in it are variable, ranging from 0*4 to 6 per cent. 
 They consist of ordinary sero-albumin, paraglobulin, 
 and fibrinogen. Unless withdrawn from inflamed 
 tissues, or blood is present, they rarely spontaneously 
 coagulate, biit do so on the addition of fibrin ferment, or 
 are allowed to stand some time. They contain only a 
 small proportion of fatty matters, about "05 per cent., 
 and in old-standing cases the ether extract yields chole- 
 sterin. The extractives are urea, a variable amount of 
 glucose, and sometimes a little leucin. The spectrum of 
 sero-lutein may be sometimes obtained by allowing the 
 serum to stand and deposit, and then filtering it till 
 quite clear. The clear fluid will give a band at f; and a 
 very faint one between F and G (MacMunn). The salts 
 are those of the blood. The exudation occurring in 
 s[)ecial serous cavities differs little from that poured into 
 the subcutaneous areolar tissues. Tliey are, perhaps, 
 generally richer in proteid matters, and the fluid of 
 the pericardium and hydrocele fluid yields a larger pro- 
 portion of fibrinogen. The latter fluid also frequently 
 contains succinic acid, and more cholestei-in than is 
 met with in other effusions. The cerebro-spinal fluid 
 is accumulated in large quantities in cases of sj^ina 
 bifida, and chronic hydrocephalus. It is a clear fluid 
 of low specific gravity, does not coagulate when heated, 
 but becomes opalescent, and deposits a flocculent 
 precipitate on the addition of acetic acid. It does 
 not contain fibrinogen, so that it yields no coagulum 
 when fibrin ferment is added to it. Sugar is said to 
 be genei-ally present, but some say that it is only to 
 be found when there is irritation or inflammation of 
 
278 Clinical Chemistry. [Chap. vi. 
 
 the brain or spinal cord. It is to be regretted that 
 more complete analyses of this fluid have not been 
 made. It is a question that occasionally arises in 
 surgical practice [Med. Clin. Trans., vol. ix., p. 247) 
 whether in punctured wounds of the back the aqueous 
 fluid that may be discharged from the wound comes 
 from the cerebro-spinal canal or from injury of the 
 kidney.* In the case Mr. Holmes brought before the 
 Society it was doubtful whether the fluid came from a 
 wounded ureter or from the cerebro-spinal canal. An 
 analysis of the fluid Avhich I made for Mr. Holmes 
 gave a very doubtful result. It was alkaline, and 
 contained 9 'So parts of water to '15 of solids. The 
 solids consisted of an ordinary albumin coagulable by 
 heat, and an albumin not so coagulable, but precipit- 
 able by acetic acid ; there was a slight greasy residue 
 left from the evaporation of the etherial extract, but 
 no cholesterin. There were traces of urea, -07 in 100 
 parts, but no uric acid or glucose. The salts consisted 
 chiefly of sodium chloride '05 and phosphates 'O-S in 
 100 parts. The amount of fluid that escaped from 
 the wound was considerable, three large draw-sheets 
 being soaked in the course of the day. The general 
 character of the fluid was not unlike that from a 
 spina bifida, except the coagulable albumin, which, 
 however, might have come from the wound. The 
 trace of urea was not more than one would expect 
 to meet with as an extractive in a fluid of this char- 
 acter, whilst it was greatly below the aiBount found 
 in even extremely dilute urine. On the other hand, it 
 is difiicult to imagine such an enormous quantity could 
 have escaped from the cerebro-spinal canal for such a 
 continued period ; and again, it was noticed that when 
 
 * "Section of the renal nerves is followed by a most copious 
 secretion by what has been called hydruria and polyuria, the 
 iirine at the same time frequently becoming albuminous." — 
 Prof. M. Foster, " Textbook of Physiology," p. 274. 
 
Chap. VI.] Ovarian Cysts. 279 
 
 the wound was partially closed the urine passed by 
 the urethra increased in quantity. 
 
 The liquor amnii and allantoic fluids are xisually 
 clear and without colour. The proportion of water to 
 the solids is veiy small. They contain traces of 
 ordinary albumin, about 0*1 to 0-15 per cent., but 
 contain no fibrino-plastic or fibrinogen. During the 
 early period of gestation they contain a considerable 
 amount of sugar, which, however, gradually disappeai's 
 as pregnancy advances, till at the time of birth every 
 trace has disappeared. {See page 206.) There is a 
 variable quantity of urea always present. The 
 allantoic fluid contains a characteristic ingredient 
 allantoiii (§ 67, page 50). The inorganic constituents 
 of both fluids consist chiefly of sodium chloride and 
 calcium and magnesium phosphate. 
 
 Synovia, or the secretion of the synovial membrane 
 of joints, is denser than the fluid obtained from serous 
 sacs, and more viscid from containing mucin. (For 
 the systematic examination of dropsical fluids see 
 Ovarian cysts, page 282.) 
 
 (3) Contents of ovarian cysts. — Considerable differ- 
 enoes of opinion, especially as regards the chemical 
 composition, exists as regards the nature of their 
 contents. This is owing, no doubt, to tlie want of 
 attention being paid to the nature of the degene- 
 rative processes that produce them. Thus, for 
 instance, we have in some cases apparently only a 
 sim])le fluid, poor in albumin, of low specific gravity, 
 and which does not yield fibrin on the addition of 
 fibrin ferment. In others the contents are viscid and 
 jelly-like, rich in proteid elements, and which yield 
 an abundant coagulum with fibrin ferment ; in some 
 of these, again, mucin will be found, in others it is 
 absent, and we have instead a body resembling 
 collagen or gelatin. It was formerly thought that 
 paralbumin and metalbumin were characteristic 
 
28o Clinical Chemistry. [Chap. vi. 
 
 constituents of ovarian cysts, biit they have been 
 found in the contents of renal cysts. MacMunn 
 believes that the spectroscope will enable us to 
 distinguish the contents of parovarian and ovarian 
 cysts from other fluids resembling them, and has 
 described the spectrum in three cases of parova- 
 rian and one case of ovarian fluid that gave %he 
 same spectrum, that of acid hsematin ; viz., a band 
 between c and d, nearer c, another between d and 
 E ; on adding ammonium sulphide to this fluid the 
 bands of reduced hsematin appeared at once, A fifth 
 specimen, however, gave no spectrum whatever. At 
 present, then, we have no one characteristic that can 
 enable us chemically to distinguish between the fluid 
 of an ovarian cyst and the contents of a cyst of 
 another organ. If the solid constituents be above that 
 of ordinary blood serum, we can say positively the 
 fluid is not ascitic, but otherwise we have to depend 
 on an examination of the whole constituents of the 
 fluid before we can venture to form an opinion. The 
 organic matters vary considerably from -25 to 14'0 
 per cent. ; the inorganic constituents, however, are 
 tolerably constant, ranging from •! to "9 per cent. 
 The proteid substances consist of ordinary albumin, 
 paraglobulin, sometimes of fibrinogen. Two proteid 
 bodies paralbumin and metalbumin, are so generally 
 present they are supposed to be characteristic con- 
 stituents. Their composition seems to be doubtful. 
 Paralbumin was first obtained by Scherer ; its alka- 
 line solutions are ropy and viscid ; it is precipitated 
 from its warm solutions by carbonic acid gas, but 
 not by magnesium sulphate ; it is coagulated by 
 rdtric acid, but the precipitate re-dissolves in strong 
 acetic acid. It seems to be associated with a body 
 resembling glycogen, and capable of being converted 
 into a substance giving the reactions of dextrose 
 with copper. Paralbumin may be a transitional 
 
Oiap. VI.] Hydatid Cysts. 281 
 
 form of mucin, since Eichwald has found that wlien 
 hcatfd with dihite mineral acids, mucin yields acid 
 albumin, and another body which closely resembles 
 dextrose by reducing solutions of cupric sulphate, 
 Metalbumin closely resembles paralbumin, and perhaps 
 is more closely related in its reactions to mucin than 
 that body. Both bodies may therefore be inter- 
 mediate products of the transformation of proteid 
 substances into mucoid or colloid matter. Mucin is 
 found in some cysts, but not in all ; it is the most 
 variable of all the organic constituents. Ovarian 
 fluids yield about O'G per cent, of fatty matter, and 
 sometimes crystals of cholesterin separate out and 
 float on the surface. The salts do not differ materially 
 from those of blood-ash. The fluid from hydatid cysts, 
 if the sac be not inflamed, is limpid Avhen running 
 from the cunnula, but becomes opalescent on standing. 
 The reaction is alkaline, and the specific gravity 
 ranges from 1'009 to 1"013. According to Murchison, 
 the fluid of the hydatid cysts contains no albumin, but 
 Naunyn has found traces. If to the contents of an 
 hydatid cyst magnesium sulphate be added, and then 
 a stream of COj be passed through, and the fluid heated 
 to 75* C, a fine precipitate of ])araglobulin and sero- 
 albumin will generally be obtained if there has been 
 inflammation of wall of the cyst. The fluid, how- 
 ever, contains no urea. The great chai'acteristic, 
 however, of the fluid of an hydatid cyst is the con- 
 siderable amount of sodium chloride it contains, a 
 quantity not found in any other fluid in the body 
 whether healthy or morbid. These characters, even 
 if the " booklets " are absent, are generally sufficient 
 to determine the nature of the fluid. It may, how- 
 ever, be mistaken for the fluid from hydro-nephrotic 
 cysts. This is of low specific gravity, 1-004, contains 
 no albumin (paralbumin and cholesterin have been 
 found by Dr. Schetelig, of Hamburg, in a renal cyst). 
 
282 Clinical Chemistry. [chap. vi. 
 
 Urea and uric acid are often absent ', the reaction is 
 generally faintly acid, more frequently neutral, and 
 although containing an abundance of sodium chloride, 
 it is not so rich in this salt as the fluid of an hydatid 
 cyst. The method of procedure for an analysis of 
 dropsical or ovarian fluids is as follows : Evaporate 
 a weighed portion of the fluid (§ 92, page 66) to 
 ascertain proportion of water and solids, and the 
 residue incinerated to determine the saline con- 
 stituents (§ 101, page 93) ; the reaction is ascer- 
 tained (§ 93, page 67) ; the proteids are determined 
 by precipitating from a weighed quantity of fluid the 
 paragiobulin, and fibrinogen if present, by precipita- 
 tion with magnesium sulphate (page 31) ; remove 
 precipitate, and acidulate filtrate with a few drops 
 of dilute acetic acid, and coagulate the ordinary al- 
 bumin by heat (§ 98, page 84). After the removal of the 
 proteids, evaporate the filtrate to dryness, and extract 
 with ether to remove fatty matter, which can be 
 estimated according to directions given, § 99, page 
 85. The residue, after the removal of the ether, 
 is then treated successively with boiling water and 
 boiling alcohol, and the aqueous and alcohoKc extracts 
 mixed together and evaporated to dryness, and then 
 dissolved in hot water, and the amounts of urea and 
 glucose determined by processes given at § 100, pages 
 87 and 88. In a fresh sample of the fluid examine 
 for special products, as paralbumin, metalbumin, suc- 
 cinic acid ; take the specific gi-avity according to di- 
 rections § 92, page 65 ; examine fluid with spectroscope 
 for bands sero-lutein (page 277), or ha?matin (page 77). 
 162. Clieinical chang:es in feone chiefly re- 
 late to the variations occurring between the insoluble 
 salts in relation to the organic basis. Thus, for 
 instance, in the atrophy of bones met with in cases 
 of long-standing anchylosis, dislocations, etc., when 
 the compact and cancellous tissue gradually becomes 
 
Chap. VI.J 
 
 JJlSJCASKS OF Bo.Mi. 
 
 283 
 
 absorl)C(l, altliougli tho whole bone is smallcT and 
 lighter, y(!t tlie proportion of inorganic constituents 
 to the organic is relatively more than in lu altliy 
 bone. The same occurs as the result of chronic 
 inllamniation of bone, where new formation of osseous 
 tissue takes place in the enlarged Haversian central 
 cancellous spaces, and the whole bone is converted 
 into a dense, heavy mass. In rickets and osteo- 
 malacia, the opposite condition maintains, and the 
 bones allected have their calcareous elements dimi- 
 nished. The following tables, giving analy.ses of the 
 tibia, will best show the composition of bono under 
 difierent conditions : — 
 
 Analyses or Normal Bone (Tiiua). 
 
 
 -eg as 
 
 8 2 -=5 >> 
 
 
 11 
 
 
 3 a 
 Pl.o 
 
 4) 
 
 '^ 2 
 
 
 feS Um 
 
 ^ 
 
 
 OP. 
 
 ^% 
 
 d-^ 
 
 
 
 
 
 
 
 W 
 
 Or!:?!inic matters 
 
 ! 
 
 .10-37 i 43-42 
 
 32-29 
 
 31-97 
 
 38-02 
 
 41-16 
 
 48-56 
 
 Ciilciiini pliosijbate 
 
 53-43 
 
 48-55 
 
 59-74 
 
 58-95 
 
 52-93 
 
 49-01 
 
 41-77 
 
 M;i;^nepiiiin pbosi>liate . 
 
 2-00 
 
 1-00 
 
 1-34 
 
 1-30 
 
 0-25 
 
 1-54 
 
 0-87 
 
 Ciilcium ciarLioiaate . 
 
 3-10 
 
 5-79 
 
 6-00 
 
 7-08 
 
 7-G6 
 
 7-76 
 
 7-10 
 
 Soluble salts . 
 
 1-07 
 
 1-24 
 
 0-G3 
 
 1-55 
 
 1-11 
 
 0-52 
 
 1-67 
 
 Analyses of Morbid 
 
 Bone.* 
 
 
 
 
 m 5 
 
 It 
 
 la 
 
 . 
 
 la 
 
 
 .Sj3 
 
 9 A 
 
 <spl 
 
 A 'A 
 
 ° a 
 
 
 p^ '?; 
 
 
 C3 
 
 Sm 
 
 r1 
 
 
 h^ 
 
 MHl 
 
 !> 
 
 
 R,'> 
 
 
 
 
 
 
 
 
 
 Orgniiic matter 
 
 66-36 
 
 75-69 
 
 55-88 
 
 4410 
 
 48-55 
 
 Calcium pliosphate 
 
 26-94 
 
 18-83 
 
 34-38 ) 
 1-181 
 
 48-20 
 
 ( 47-99 
 1 1-55 
 
 M.-isrut.'sium pliosphate . 
 
 0-81 
 
 0-54 
 
 Calducu carbonate 
 
 4-88 
 
 3-8:5 
 
 6-63 
 
 7-45 
 
 1-00 
 
 Soluble salts . 
 
 1-08 
 
 0-43 
 
 1-91 
 
 0-55 
 
 0-91 
 
 * These analyses -were made from typical, but not exti-eme, 
 instances of the disease. 
 
284 Clinical Chemistry. [Chap. vi. 
 
 Bone contains less water in proportion to its 
 solids than any other tissue, except enamel and den- 
 tine, pulverised bone evaporated to dryness losing 
 only 10 per cent, of its weight. From the fact that 
 when perfectly dried bone is placed in water there is 
 a slight elevation of temperature, it is supposed that 
 the water exists in bone partly in a state of chemical 
 combination, like the water of crystallisation. The 
 organic matter may be obtained by digesting a frag- 
 ment of bone for some time in dilute hydrochloric 
 acid (1 — 5), when the inorganic matters will be dis- 
 solved, leaving the gelatinous matrix intact. This 
 consists of a body identical with collagen (which, by 
 long boiling, yields gelatin, and gelatin again, by 
 being heated above boiling-point (130° C), is re- 
 converted into collagen) mixed with a small quantity 
 of elasticin, and traces of proteid, and some fat. 
 Most of the fat of bones, however, is found in a free 
 state in the yellow marrow of the medullary cavity of 
 the long bones, and, to a lesser extent, in the red 
 marrow of the cancellated tissue. The yellow marrow 
 differs little from ordinary fatty matter, and consists 
 chiefly of an admixture of neutral fats. The red 
 marrow yields much less fatty matter than the yellow ; 
 it contains a proteid body ; a free acid (lactic acid V), 
 a product of decomposition ; hypoxanthin ; and cer- 
 tain granules which stain a deep blue with potas- 
 sium ferrocyanide, and therefore probably contain 
 iron. In addition, there are large multi-nucleated' 
 cells (^Myeloplaxes of Robin), which play an impor- 
 tant part in the absorption and formation of bone. 
 These and the granular bodies, according to Heitz- 
 mann, Malassez, and others, have also to do with 
 the formation of the red blood - corpuscles. In 
 pernicious anaemia and leucaemia, where nucleated 
 coloured corpuscles similar to those found in the blood 
 of the human embryo exist, the marrow of the bones 
 
Cliap. VI.] AXALVSIS OF BoNE. 285 
 
 is also generally afTccted ; hence tlio term " niyo- 
 logciiic l(Hic;i'inia." The inorganic constituents can be 
 obtained l)y incinerating some of the crushed bone in 
 a inuflie furnace, which burns off the organic matter. 
 In addition to phosphoric acid, carbonic acid, and 
 chlorine in combination with lime, there exists a 
 minute quantity of fluorine, about 0*22 parts in 100 
 of bone-ash. Some of the other metals are occa- 
 sionally met with, as strontium, aluminum, silicon, 
 copjicr, and arsenic. By long keeping, bones yield 
 relatively less organic matter than fresh, but their 
 inorganic constituents are little altered. Dr. Norman 
 Moore has {Path. Soc. Trans., 1883) shown some 
 interesting si)ecimens of fossil bone, which were 
 evidently from a subject that had suffered from 
 chronic rheumatic arthritis. 
 
 To make an analysis of diseased bone, it is 
 advisable to take a section representing both the com- 
 pact and cancellated part, and a similar section in 
 which the compact part is carefully divided from the 
 cancellous, and submit them all to a separate analysis. 
 In this we learn the chemical changes that have 
 taken place in the bone as a whole, and the changes 
 that have affected the compact and cancellous portions 
 respectively. If possible, it is as well, from the same 
 subject, to examine a portion of a bone as nearly 
 resembling in form and structure the one diseased, 
 but which is apparently free from the disease. The 
 fragments of bone are to be reduced to a fine powder, 
 and the weight ascertained. (Ten grammes is a con- 
 venient quantity to take.) The powder is then 
 placed in a weighed platinum crucible, and dried on a 
 calcium chloride bath at a temperature of 130° C. till it 
 ceases to lose weight. The loss of weight represents 
 the amount of water. The finely-dried powder is 
 extracted with ether, by means of the apparatus 
 described page 2G3 ; this gives the amount of fatty 
 
286 Clinical Chemistry. [Chap. vi. 
 
 matter; and the etherial residue is examined, as di- 
 rected § 99, page 85, to determine the nature of the fats. 
 The powder, after exhaustion by ether, is again weighed 
 in the weighed platinum crucible, then incinerated in 
 a muffle furnace till the ash is quite white, allowed to 
 cool over sulphuric acid, and, when cold, weighed. 
 The loss of weight represents the organic matter ; the 
 actual weight, the inorganic residue. The ash is then 
 boiled at 100° C. in distilled water for some time, by 
 which means the soluble salts are dissolved. Filter, 
 evaporate filtrate, and weigh ; the weight of residue 
 represents weight of the soluble salts. If required, 
 estimate the sodium by process described § 88, page 61, 
 and the hydrochloric acid, § 114, page 136, and the 
 carbonic acid, page 287. The insoluble residue 
 not dissolved by boiling water is then dried and 
 weighed, the weight representing the insoluble salts. 
 Dissolve these in acetic acid, and divide the solution 
 into two equal parts. One portion of the solution 
 is then examined according to the directions given 
 §§ 84:, 85, for quantitative determination of lime and 
 magnesia. The other portion is heated according to 
 the directions given for the estimation of phosphoric 
 acid § 113, and for hydrochloric acid, § 114. Having 
 obtained the total amounts of sodium, calcium, and 
 magnesium, and the amounts of phosphoric acid and 
 hydrochloric acid, the result of the analysis is 
 calculated as follows : The amount of hydrochloric 
 acid obtained by the aqueous solution is combined 
 with the sodium, and calculated as sodium chloride, 
 and any overplus of soda is combined with the car- 
 bonic acid and reckoned as sodium carbonate. The 
 whole of the magnesium is combined with phosphoric 
 acid as magnesium phosphate, and the excess of 
 phosphoric acid is deducted from the original amount 
 of phosphoric acid obtained by volumetric analysis. 
 This is combined with the lime, and calculated as 
 
Ciiap. VI.] AiVALVSIS UF BONE. 287 
 
 calcium phosphate. But as it is insufficient to coui- 
 bino with tlic whole of the lime, the amount of hydro- 
 chloric acid obtained from the acid solution (not from 
 the aquevous solution, which has been combined with 
 sodium to form sodium chloride) is calculated as 
 calcium chloride, and the })ortion of the lime that 
 still remains uncou\bined is then taken as calcium 
 carbonate. The fluorine may be determined either 
 by making an exact determination of the carbonic 
 acid existing in lime, instead of assuming that the 
 whole of lime that is not combined with phosphoric 
 acid and hydrochloric acid as given above. It is then 
 found that a minute quantity of lime is in excess of 
 what is required to form calcium carbonate, and this 
 quantity represents the amount that combines to form 
 calcium fluoride. To estimate the quantity of car- 
 bonate lime, a weighed quantity of unburnt bone, 
 finely pulverised, is to be thoroughly extracted with 
 boiling water to remove soluble chlorides. The 
 residue dried, and placed in a glass flask fitted with a 
 desiccating tube ; a test-tube containing hydrochloric 
 acid is then placed in the flask, so arranged that by 
 means of a fine wire passed through the cork of the 
 flask it may be allowed to flow gradually over the 
 dried portion of bone at the bottom of the flask. The 
 apparatus and its contents are then weighed ; the 
 hydrochloric acid is poured gentl}"- over the powdered 
 bone, till it ceases to effervesce on addition of acid. 
 The flask is then shaken from time to time to dis- 
 engage any gas that may be remaining, and afterwards 
 weighed, the loss of weight representing the amount 
 of carbonic acid in combination with the lime. Now, 
 by the previous process we have determined the total 
 amount of lime in the ash of bone, and have found 
 how much combines with the phosphoric acid, how 
 much with hydrochloric acid, and now we have found 
 the quantity that goes to form calcium carbonate ; the 
 
288 . Clinical Chemistry. [Chap.vi. 
 
 overplus of lime, therefore, that remains after these 
 calculations may be reckoned as calcium fluoride. 
 The determination, however, of calcium fluoride is of 
 little practical value in clinical or pathological investi- 
 gations, so that the direct determination of the calcium 
 carbonate need not necessarily be resorted to ; and the 
 analysis of bone may be concluded by the indirect 
 determination of the carbonate, that is, by the pro- 
 cess of calculating out first the amount of lime 
 combined with phosphoric acid, and the amount 
 combined with hydrochloric acid, leaving the over- 
 plus of lime to be calculated as carbonate. The 
 presence of fluorine can be determined by treating 
 large quantities of the ash of bones with strong 
 sulphuric acid, and gently heating the mixture in a 
 glass vessel, when the glass will become corroded. 
 If the glass vessel has been previously weighed, the 
 amount of fluorine can be determined by the loss of 
 weight the glass sustains. 
 
 With regard to the chemical changes taking place 
 in bone in rickets, much difi'erence of opinion has been 
 expressed. It has been held that the calcareous salts 
 are not retained, owing to the inability of the organic 
 matrix to fix them ; or that they are dissolved out 
 of the matrix, owing to the excessive formation of 
 lactic acid in the system. These views have been 
 based upon the supposition that the urine contains an 
 excess of lime salts. This is based, however, on very 
 insufficient evidence, and is not confirmed by the 
 more recent analj^ses of urine from rachitic patients, 
 which points very conclusively to the fact that the 
 lime salts are not excessively excreted by the kidneys 
 in this disease. Dr. Seeman {Zur Pathogenese und 
 Etiologie der Rachitis; Vir chow's Archiv., Ixxvii., 
 1879), who has analysed the urine of sixteen rachitic 
 children, has actually found a diminution, which was 
 most marked when the disease was at its height. It 
 
chnp. VI.] Rickets and Ostecvalac/a. 2S9 
 
 is proliablo that the bone changes in rickets are due to 
 a lime starvation rather than to a lime withdrawal ; 
 the salts of that base not being introdticed in sufficient 
 quantity into the system, the catarrhal condition of 
 the mucous membrane of the intestines, which invari- 
 ably accompanies this disease, hindering their absorp- 
 tion. A condition termed hsemorrhagic rickets has 
 lately been described ; it is doubtful whether this is 
 related in any way to scurvy, or, to speak more accu- 
 rately, the result of a scorbutic condition, or is merely 
 an exaggeration of the hypera^mic condition of the 
 periosteum, which is more or less always noticeable in 
 the bones of rickety children. This is a question for 
 histologists to decide, but it is an interesting fact that 
 these cases improve under the administration of 
 lunc-juice. In osteomalacia the poverty of bone in 
 calcareous constituents evidently depends on the re- 
 absorption of the lime salts, since not only does the 
 urine demonstrably show an excess of earthy phos- 
 phates, but these salts are also deposited in the tissues. 
 (See Calcai'eous degeneration, page 272.) Some have 
 supposed that the withdrawal is due either to excessive 
 formation of lactic acid in the system, or to its local 
 formation in the bone itself. The fact that lactic 
 acid administered in large quantities, as in the lactic 
 acid treatment of diabetes, or experimentally in the 
 case of animals, seems to show that excessive forma- 
 tion of lactic acid is not the cause. It is probable 
 in this case that the process is truly a degenerative 
 one, like myxoedema, and in which the organic 
 matter of the bone reverts to its embryonic con- 
 dition, which Morochowitz believes to be a mixture 
 of collagen and mucin. It is interesting to ob- 
 serve, in connection with its probable relation to 
 myxcedema, that it most frequently attacks women, 
 at about the same age when myxcedema makes its 
 appearance. 
 
 T 
 
290 Clinical Chemistry. [Chap. vi. 
 
 Scurvy, i^oiit, a^nd rlieumatism. — These 
 diseases may be considered as typical examples of 
 disorders arising, in the first instance, from chemical 
 alterations in the quality of the blood. In their 
 early stages, or ill-defined forms, they often present 
 many features common to each other. Indeed, the 
 close resemblance between gout, rheumatism, and 
 scurvy in their early stages repeatedly attracted the 
 notice of the older writers on the subject. Thus, 
 Sydenham* says, " where matter suited to produce 
 the gout is newly generated there appear various 
 symptoms which occasion us to suspect the scurvy, 
 till the formation and actual appearance of the gout re- 
 move all doubt concerning the disordei". " The symptoms 
 common to these disorders in their early stages may 
 be thus briefly enumerated. Fugitive and erratic 
 pains in the limbs ; tenderness of the joints ; attacks 
 of dyspnoea, more or less paroxysmal in character ; 
 severe attacks of pain over the i-egion of the heart ; 
 weak and intermittent pulse ; irregular discharge of 
 urine, sometimes profuse and of low specific gravity, 
 at other times scanty and concentrated ; and a ten- 
 dency to subcutaneous haemorrhages \ whilst one point 
 in common to these symptoms, worthy of especial con- 
 sideration, is their extreme motility, the paroxysmal 
 nature of their onset, the suddenness with which they 
 disappear or transfer themselves from one region or 
 organ to another. These sudden changes afibrd ad- 
 ditional support to the view that these derangements 
 are caused by chemical alterations in the quality of 
 the blood. What the precise nature of these chemical 
 changes may be is not yet definitely established, but 
 evidence is gradually increasing which points more 
 and more to the conclusion that they arise from a 
 diminution of the normal alkaline reaction of the 
 blood. 
 
 • "De Eheumatismo," sect. 6, cap. v. 
 
Chap. VI.] ScuKyy. 291 
 
 With regard to scurvy, the most important ob- 
 servations liave been made by Mr. Busk and Dr. 
 Garrod. The former, in a series of analyses of blood, 
 published in Dr. G. Budd's article on Scurvy, in the 
 " Library of Medicine," showed that in this disease there 
 was a considerable diminution of the corpuscles and 
 increase in the fibrin, and an augmentation of the in- 
 organic residue. Unfortunately, Mr. Busk did not 
 complete his observations by making a separate esti- 
 mation of each of the inorganic constituents. In ISiS, 
 however. Dr. Garrod found that in the urine of scurvy 
 patients the potash salts were considerably diminished. 
 This observation of Dr. Garrod I was able to confirm 
 in 1877.* Dr. Garrod thought that this diminution 
 of potash was due to a deficiency of this base in the 
 food of those affected, but it has been subsequently 
 shown that this cannot be the case, since peas, which 
 form an important item of the sailor's diet, are rich in 
 this substance ; and, moreover, if we give patients 
 suffering from the disease unlimited quantities of 
 Liebig's extract of meat, a food extremely ricli in 
 potash salts, no amelioration occurs till lemon juice, 
 potatoes, or other fresh vegetable substance is ad- 
 ministered as well. This suggests that scurvy does 
 not depend on the withdrawal of potash from the 
 system, but on some alteration subsisting between the 
 organic acids and the base. With regard to this point, 
 I was able to establish the important fact that the 
 urine passed by scorbutic patients was deficient not 
 only in potash but also in the alkaline phosphates. 
 Thus, after the withdrawal of all vegetable food for 
 eighteen days, I found the alkaline phosphates had 
 sunk from 2-1 grms. to 1'5 grms., whilst there was a 
 slight increase of the earthy phosphates. Again, in 
 four cases of scurvy, two of which are related in my 
 
 * "An Enquiry into the General Pathology of Scurvy." Le-\vis, 
 1877. 
 
292 Clinical Chemistry. [Chap. vl 
 
 pamphlet, and two I have subsequently observed, 
 I found in the first case that the alkaline phosphates 
 on admission were as low as 0'76 grm., but that 
 on the administration of lemon juice, the diet in other 
 respects being the same, they rose to 1 '6 grms. In the 
 second case, the amount on admission was 0'57 grm., 
 which rose after administration of lemon juice to 1'6 
 grms. In the third case the rise was not so marked, 
 being from 1'25 grms. to 1'77 grms.; and in the fourth 
 case the lemon juice increased the amount from 0"87 
 grm. to 1 "29 grms. In all these cases the diet was the 
 same throughout, the only difference being the ad- 
 ministration of a small quantity of lemon juice (2 oz. 
 daily), which could not possibly account for the de- 
 cided increase of the alkaline phosphates. It therefore 
 seems to me that these salts are retained in the system 
 in scurvy to supply the deficiency of the other alkaline 
 salts, the alkaline carbonates and bicarbonates, which 
 are withdrawn when fresh vegetables are withheld. 
 This view is in accord with the experiments of Hoff- 
 mann and Loscar, to which attention has been already 
 called {§ 93, page 68). There can be no doubt that 
 the alkalescence of the blood is mainly dependent on 
 the formation of the alkaline carbonates derived from 
 the reduction of the organic salts, the lactates, malates, 
 citrates, etc., introduced with the food, chiefly by vege- 
 tables, but also, as the experience of Dr. Neal in the Eira 
 Expedition tends to show {Med. and Chir. Soc. Trans., 
 1883), with fresh meat as well. When this supply is 
 cut off, as is the case in long voyages or in sieges, etc., 
 the blood is deprived of one of its sources for maintain- 
 ing its alkalescence at its normal point, and conse- 
 quently it falls back on the other alkaline salts, viz., 
 the alkaline phosphates, to supply the deficiency. In 
 this way it may maintain the proper degree of alka- 
 linity for a time, but after a while a minimum point 
 is reached which is incompatible with healthy nutrition, 
 
Chap. VI.] SCURI'V. 293 
 
 a,nd textural changes are the result. These changes in 
 scurvy re.sciiil)lc closely those induced in animals, iu 
 whom, by feeding with food rich in acid salts, or by 
 the direct administration of acids, the alkalinity of the 
 blood has been slowly diminished, viz., dissolution of 
 the blood globules, ecchymoses in the heart, blood- 
 stains in the mediastinum, gums, and mucous surfaces; 
 ■whilst the muscular structure of the heart and muscles 
 generally, as well as the secreting cells of the liver and 
 kidney, become granular and even distinctly fatty 
 (§93, page 09). With regard to the influence of the 
 oi-ganic salts in the prevention of scurvy, it is inter- 
 estmg to remark that their range is apparently limited. 
 Experience has shown us that fresh vegetables alone 
 ai'e eflicacious as anti-scorbutics, and the same may be 
 said of meat. In Arctic regions, where the meat is 
 frozen almost as soon as killed, and in hot countries, 
 where it is eaten before the changes induced by rigor- 
 uiortis set in, meat is considered as highly anti-scorbutic. 
 In Europe, where the meat is generally kept some 
 time before it is used as food, it is not so reputed. The 
 exjilanation of this lies in the fact that fresh vege- 
 tables and meat undergo changes by keeping with 
 regard to the relation of the organic acids to the bases. 
 Thus, the juices of fresh vegetables contain a certain 
 quantity of organic acid (malic, citric, tartaric, etc.) 
 in combination with a definite quantity of a base. 
 On keeping, fermentative changes take place in the 
 saccharine elements (as we see in fodder preserved by 
 ensilage), and an additional quantity of free organic 
 acid is foi'med (this in the case of vegetables is acetic 
 acid), whilst the quantity of the base in the vegetable 
 remains constant. Now this additional acid takes a 
 portion of the base from the existing salts, reducing 
 them from alkaline or neutral salts, with three or two 
 equivalents of base, to acid salts, with only one equiva- 
 lent. These acid salts, the malates, citrates, acetates, 
 
294 Clinical Chemistry. [Chap.vi. 
 
 etc., in turn are reduced in the blood to acid carbonates 
 (bicarbonates), salts which, though they may have an 
 alkaline "reaction, play the part of an acid in the 
 system, and effect decompositions with neutral salts in 
 all respects like acids (see formulse, pages 24, 70, 183). 
 The same may be said with regard to meat, since after 
 rigor mortis* has set in there is an increase of lactic 
 acid in its juices, so that acid instead of alkaline lactates 
 are formed. From the foregoing it will be gathered 
 that the development of scurvy depends in the main 
 on a change in the conditions of the blood, in the di- 
 rection of a diminution of its alkalescence, and that 
 this diminution may be caused either by the direct 
 cutting off of organic salts which yield by oxydation 
 alkaline carbonates in the blood ; or indirectly, though 
 not nearly so immediately, by the continued use of 
 food which contains acid instead of alkaline salts. 
 And further, that this change in the composition of the 
 blood is more real than apparent, since the acid salt is 
 a bicarbonate of potash or soda, a salt which has an 
 alkaline reaction, and so apparently continues to give 
 blood its alkaline reaction, whilst its chemical consti- 
 tution is that of an acid salt, and acts as such in the 
 chemical decompositions it occasions in the body. It 
 is only by this means, as we have seen when discussing 
 the nature of the reaction of the urine and the gastric 
 juice (§§ 107, 179), that we are able to account for the 
 seeming paradox of the separation of these acid secre- 
 tions from the alkaline blood. 
 
 * It has been pointed out as an objection to the view that kept 
 meat has no anti-scorbutic virtues, that the South American hunters 
 subsist almost entirely on dried hung meat. So that if scurvy de- 
 pended on the undue development of acid in the juices of the 
 meat after having been killed some time, these men ought to suffer 
 from scurvy, whereas they are remarkably free from the disease. 
 It is probable, however, that the rapid drying of the freshly killed 
 meat under a tropical sun j^uts a stop to the fermentative changes 
 that produce excess of lactic acid, so that the "jerked" beef of 
 tropical countries resembles the frozen meat of Arctic regions. 
 
Chap. VI.] Gout. 295 
 
 In gout a diniimition of the alkaline reaction of 
 tlie blood has also b(!on observed. Dr, Garrod has 
 pointed out, that with the exception of collapsed 
 cholera, and perhaps certain cases of albuminuria, the 
 reaction of the blood is to be found neunsr the neutral 
 point in severe forms of chronic gout than in any other 
 disease. This diminished alkalinity in the blood of 
 gout has a relation to that which happens in scurvy, 
 for though it does not depend on the actual withdrawal 
 of alkaline salts supplied by fresh fruits and vegetables, 
 yet the diminution is caused by the addition of acids 
 or acid salts taken in excess with the food, or retained 
 in the system, the result of imperfect elimination, etc. 
 It is generally held that the excessive formation of uric 
 acid is the reason of the phenomena observed in this 
 disease, but the idea is gaining ground that the pre- 
 sence of this substance in the blood, and its deposit in 
 the tissues, is not caused by excessive formation, but to 
 the fact of its retention in the system and to its insolu- 
 bility. When speaking of uric acid (§ 111) it was 
 stated that this substance is never found in normal 
 blood, or perhaps even in the blood of any disease 
 except gout, and it is considered probable that in 
 man it is not formed in the body to the extent that 
 had been supposed. Indeed, the evidence seems to 
 point to that fact, that the quantity formed in health 
 is extremely small, and that it is desti'oyed almost as 
 soon as formed, and so never enters the general current 
 of the circulation. Whilst the small quantity (0'5 grm.) 
 that escapes daily by the kidney does not probably repre- 
 sent the amount foi'med in the body, but is simply the 
 uric acid formed by the kidney itself, and which passes 
 directly out of the body instead of being destroyed. In 
 gout, however, we have decided evidence that uric acid 
 is present in the blood, that it is deposited in certain 
 tissues; and also, although the evidence is not quite 
 satisfactory to me that even the small quantity of uric 
 
296 Clinical Chemistry. [Chap. vi. 
 
 acid "wliicli appears in normal urine is reduced. Dr. 
 Garrod considers gout to depend upon a failure of the 
 renal function to excrete uric acid. In this way he 
 accounts for the diminution of uric acid from the urine 
 and its accumulation in the blood ; whilst its deposition 
 in the tissues depends on this accumulation, and on the 
 fact that uric acid is present in the blood in the form 
 of insoluble urate of soda. If it could be satisfactorily- 
 proved that the minute quantity of uric acid, 0*5 grm., 
 constantly present in healthy urine, really came from 
 the blood, or that it was proved beyond doubt that this 
 extremely minute quantity was still further invariably 
 reduced in gouty patients, Dr. Garrod's view might be 
 accepted without challenge. But thei-e are difficulties 
 in the way of accepting the belief that the uric acid of 
 the urine comes from the system generally, whilst its 
 diminution in gout is by no means invariable ; for 
 where this diminution is chiefly observed is in chronic 
 cases, where kidney changes have been established. 
 In fact, I venture to think the accumulation of uric 
 acid in the blood, and its deposit in certain tissues, 
 depend on other conditions than failure of the renal 
 function, and that the first step in the process lies in 
 the failure of the tissues to reduce the uric acid formed 
 in them, as is the case in health. In the large glands, 
 or where the current of the circulation is free, the uric 
 acid is carried into the blood and gradually reduced to 
 urea ; in tissues outside the current of the circulation 
 the insoluble uric acid is not so readily carried off, 
 and so on the slightest disturbance is deposited, as is 
 the case in cartilages of the joints, the ear, etc. The 
 conditions which prevent the normal destruction of 
 uric acid in the tissues, and which permit it to pass 
 into the circulation, depend probably on disturbance of 
 innervation. These conditions I have endeavoured to 
 formulate in the chapter on the derangements asso- 
 ciated with deposits of uric acid, in my work " On 
 
Chap. VI.] Gout. 297 
 
 Morbid Conditions of the Urine" (p. 65). As they are 
 too lengthy to dwell upon here, it will be sufficient 
 briefly to state the conelu.sions arrived at, which are that 
 the first step in the pathology of gout is a textural de- 
 generation, either hereditary or acquired, by which the 
 tissues and blood become loaded Avith effete products; 
 that such predisposing conditions lead at last to a dis- 
 turbance of some special troi)hic nerve centre, caused 
 either by a degenerative change in its structure, or de- 
 rangement of its functions by the circulation through 
 it of impure blood. This disturbance may be con- 
 sidered the determining cause of the gouty attack. 
 The restdt is the accumulation of uric acid in the 
 blood, and the deposition of urate of soda in the 
 tissues. 
 
 With regard to the diminished alkalinity of the 
 blood noticed in chronic gout, although no doubt in 
 some measure due to the presence of uric acid and acid 
 xirates, yet excess of other organic acids undoubtedly 
 has to be taken into consideration. For if the acids 
 concerned in the production of gout were derived 
 solely from the nitrogenous elements of the food and 
 tissues, then by a rigid limitation of animal food within 
 physiological limits we might hope to check or control 
 the progress of the disease. But other articles of diet 
 besides the nitrogenous, or those which, like alcohol, 
 disturb the functions of the liver, and are thus sup- 
 posed to lead to increased formation of uric acid, give 
 rise to gouty symptoms; and it is a common experience 
 with the gouty that tliere is as much arthritic trouble 
 in a plateful of apple tart as in a mutton chop, and in 
 a few strawberries as in a glass of port wine. 
 
 In rheumatism, no observations, as far as I am 
 aware, have been made to detei-mine whether there is 
 a diminution of the alkaline reaction of the blood ; but 
 no one can have observed the enormous quantity of 
 acid poured out from the body by the skin in this 
 
298 Clinical Chemistry. [Chap. vi. 
 
 disease, or have noted the high degree of the acidity of 
 the urine during the progress of the attack, without 
 coming to the conclusion that an excessive formation of 
 acid is going on iia the system. What the nature and 
 character of the acid is, or how formed, we know 
 absolutely nothing, though some have supposed it to 
 be lactic acid. Whatever the acid may be, its de- 
 velopment seems to be local rather than general, and 
 is apparently excited by catarrhal influences rather 
 than by previous accumulation of acid in the tissues 
 and fluids. The acute manifestation of the disease 
 occurring for the most part among young adults, or 
 during the earlier period of middle age, there is not the 
 same impairment of tissue as is the case with gouty 
 patients, which may account for the non-deposition 
 of urate of soda ; or else the specific character of the 
 inflammation being excited by a different cause, and 
 not to a prolonged saturation of the tissues with acid 
 products, does not lead to the accumulation and de- 
 posit of uric acid in the tissues. 
 
INDEX 
 
 Acetic acid, 38. 
 Acetonsemia, 98. 
 Acetone, 8. 
 Acid albumin, 36. 
 
 fermentation of urine, 111. 
 
 Acid reaction, liiglily. Causes of, 
 
 112. 
 
 , how determined, 112. 
 
 of crastric jxiice, 179. 
 
 of urine, 109. 
 
 - — secretions formed from alka- 
 line blood, 21-, 111, 182. 
 Acids, Organic, 8. 
 Albnmin, final products of dises- 
 
 tion by gastric and pancreatic 
 
 juice, 217. 
 
 , sero-. Estimation of, 145. 
 
 , , Separation of, in blood, 
 
 &t. 
 
 , , , in urine, 142. 
 
 , , Tests for, 33. 
 
 Albuminuria, Causes producing, 
 
 141. 
 — — , Temporary, from functional 
 
 derangement of liver, 214. 
 Alcohol, 6. 
 Aldehyde, 7. 
 Alkali-albumin (casein), Test for, 
 
 36. 
 
 in milk, 103. 
 
 Alkaline phosphates in urine, 113. 
 
 , Estimation of, 135. 
 
 , Eeduction of, in 
 
 scurvy, 292. 
 Alkaline reaction of bUe, 193. 
 
 of blood, 67. 
 
 of dropsical fluids, 277. 
 
 of hydatid cysts, 231. 
 
 of pancreatic juice, 216. 
 
 of pus, 273. 
 
 of saliva, 176. 
 
 of urine, fl^ed, 113. 
 
 , how determined, 
 
 70, 114. 
 , volatUe, 115. 
 
 Alkaloids, Separation of, from 
 
 tissues, 192. 
 
 , Tests for, 14. 
 
 AUantoin, 50. 
 
 , Fluid of, 279. 
 
 Amides, 9. 
 Ammonia, 60. 
 
 , Formation of, in urine, 115. 
 
 Ammonio-magnesium phuspliat« 
 
 deposit in calculi, 248. 
 
 in urine, 134. 
 
 Amnii liquor, Composition of, ^79. 
 , Sugar in, at early period 
 
 of gestation, absent at full term, 
 
 206. 
 Amylum, Tests for, 9. 
 Amyloid degeneration (see Lar- 
 
 daceous), 264. 
 Analysis, 15. 
 Anazoturia, 109. 
 Anderson, Dr., on leucin in urine, 
 
 frequency of, 169. 
 Anti-albumose, 187. 
 
 peptone, 187. 
 
 Antimony, Poisoning by, 191, 230. 
 Arsenic, Poisoning by, 191, 230. 
 Ash (see Salts). 
 Asphyxia, 95. 
 Atropine, 51. 
 Azoturia, 107. 
 
 Baker, Morrant, crystalline de- 
 posit of calcivun oxalate on 
 calcidus, 249. 
 
 Baruria, 109. 
 
 Beneke, on causes of oxaluria, 228. 
 
 Benzoic acid, 42. 
 
 Bertholet on coefficient of partage, 
 181. 
 
 Bezoar stones, Nature of, 256. 
 
 Bile acids, 202. 
 
 , Composition of, 43, 44. 
 
 , Physiological action of, 
 
 203. 
 
 , Spectral analysis of, 202. 
 
300 
 
 Clinical Chemistry. 
 
 Bile acids, Spectroscopic exami- 
 nation of, 202. 
 
 , Tests for, 163. 
 
 , Analyses of, 193. 
 
 , Characters of, 194. 
 
 , Tatty matters of, 205. 
 
 in urine, Tests for pigment 
 
 and acids, 163. 
 
 jaundice, 195. 
 
 , mucin, 198. 
 
 , Physiological action of, 193. 
 
 pigments, 199. 
 
 iu gall stones, 252. 
 
 , Nature of, 199. 
 
 , Spectral analysis of, 200. 
 
 , Tests for, 163, 202. 
 
 ■ ■ salts, 205. 
 
 Hillary calculi, 250. 
 
 Bilirubin, Action of osydising 
 
 agents on s]pectrum of, 200. 
 
 ■ , Decomposition of, 200. 
 
 , how obtained, 199. 
 
 BJood, Albuminous constituents 
 
 of, 71, 84. 
 
 , Clinical examination of, 74. 
 
 , Colouring mutter of, 73, 
 
 , Extractives of, 87. 
 
 , Patty matters in, 85. 
 
 in urine, 159. 
 
 , Reaction of, 67. 
 
 , Salts iu, 93. 
 
 , Solids of, 65. 
 
 , Spectroscopic examination 
 
 of, 77. 
 stains. Chemical tests for, 
 
 83. 
 
 , Toxic conditions of, 94. 
 
 , Water of, 65. 
 
 Pone, Analysis of, 285. 
 
 , Chemical changes of, in 
 
 rickets, 288. 
 , , in osteomalacia, 
 
 289. 
 
 , Composition of, 283. 
 
 , Morbid changes in, 
 
 Brodie, Sir Benjamin, on calculi, 
 
 formation of, 238. 
 
 ■ , , fracture of, 241. 
 
 Brucine, 51. 
 
 Busk, Mr., on analyses of the 
 
 blood in scurvy, 291. 
 Butyric acid, 39. 
 ferment, 20. 
 
 Calcareous degeneration, 272. 
 Calcium, Calculation of, 287. 
 
 , Estimation of, 57. 
 
 in bones as phosphate and 
 
 carbonate, 283. 
 
 Calcium in calculi as carbonate, 
 
 249, 254. 
 
 as oxalate, 249. 
 
 as phosphate, 248. 
 
 in fasces, 223. 
 
 in urine as oxalate, 128. 
 
 Calculi, Biliary Analysis of, 253. 
 
 Characters of, 250. 
 
 , Formation of, 251. 
 
 , gouty concretions, 257. 
 
 , miscellaneoiis concretions, 
 
 259. 
 
 , pancreatic. Analysis of, 254 
 
 iiitestii)al concretions. 
 
 Enumeration of, 256. 
 
 , Prostatic, 257. 
 
 , renal and urinary, 235. 
 
 , Analysis of, 246. 
 
 , Disintegration of, 
 
 241. 
 , Origin and mode 
 
 of formation of, 236. 
 , Solvent treatment 
 
 of, 241. 
 
 , Salivary, 257. 
 
 Capric acid, ^9. 
 
 Caproic acid, 39. 
 
 Carbohydrates, Composition of, 
 
 28. 
 Carbolic acid, 42. 
 Carbonate of lime calculi, 249, 
 
 254. 
 Carbonic acid, 40. 
 
 , Estimation of, 255, 287. 
 
 Carnin, 50. 
 Casein, 36. 
 (alkali albumin) in milk, 
 
 103. 
 
 , Tests for, 36. 
 
 Cases of successful solution of 
 
 urinary calculi, 243. 
 Cerebro-spinal fluid. Analysis of, 
 
 277. 
 Charles, Dr. Cranstoun, on mucin 
 
 in case of myxoedema, 270. 
 Chemical composition of tissues 
 
 and fluids, 1. 
 Cholestersemia, 97, 205. 
 Cholesteric acid, 42. 
 Cholesterin m bile, 205. 
 
 in blood, 85. 
 
 in chyle and lymph, 101. 
 
 in gall stones, 251. 
 
 in ovarian cysts, 281. 
 
 mistaken for lu-ic acid, 259. 
 
 , Tests for, 43. 
 
 Choletelin, Formation of, 200. 
 
 in urine, 116. 
 
 ChoUc acid, 43. 
 
Index 
 
 ;oi 
 
 Clioliu (neurin), +5. 
 
 , Hoimration of, R5. 
 
 Chondi-in, 37. 
 
 Chyle, Composition of, 101. 
 
 absorbed from jejunum aiifl 
 
 upper part of ileum, 2U*. 
 
 Chylous urine, Anali'scs of, 165. 
 
 Chyme, 219. 
 
 Clark, Sir Andrew, on renal inade- 
 qiiacy, 109, 214. 
 
 Co-ellicient of partasro, 181. 
 
 Collai,'en, Decompositiou of, 269. 
 
 Colloid defjeueratiou, 268. 
 
 medium in calculous disease, 
 
 237. 
 
 Colostrum, 102. 
 
 Colouring matters of bile, 199. 
 
 of blood, 73. 
 
 of urine, 116. 
 
 Composition of organic sub- 
 stances, 3. 
 
 Coiipcr, Poisoninp: by, 231. 
 
 , Presence of, in tissues and 
 
 secretions, 206. 
 
 Corpora amylacea, 267. 
 
 Corrosive poisons, 191, 
 
 Curarine, 51. 
 
 Cystin, Characters of, 45. 
 
 in calculi, 247. 
 
 in uriue, 166. 
 
 Desreneratiou, products of, Cal- 
 careous, 272. 
 
 , , Colloid, 269. 
 
 , , (Corpora amylacea, 267. 
 
 , , Fatty, 261. 
 
 , , Hyaline, 266. 
 
 , , Lardaceovis, 264. 
 
 , , Mucoid, 26-J. 
 
 Deposits of cholesterin mistaken 
 for uric acid, 2.59. 
 
 Dextrin, Tests for, 31. 
 
 Dextrose, Tests for, 29. 
 
 Diabetes insipidus, 107. 
 
 mellitus, Acetonsemia in, 99. 
 
 , Bernard's view of, 207. 
 
 , Blood in, 98. 
 
 • , Distinguished from 
 
 glycosuria, 211. 
 
 , Dr. Pavy's view of, 207. 
 
 ■ , Estimation of sugar in, 
 
 151, 153, 155, 157. 
 
 ■ , Increase of urinary flow 
 
 in, 108. 
 
 , Origin of, 207. 
 
 -, sugar in, Tests for, 150. 
 
 Dialysis, 28. 
 
 , Separation of \irca from 
 
 blood by means of, 87. 
 
 Disintepration of calculi, atl. 
 Drafrgoridorf on bile acids in 
 
 normal ui'ine, 203. 
 Dropsical fluids. Analysis of, 277. 
 Drop.sy, how caused, 275. 
 Dyspepsia, Acid, 112, 180. 
 , Flatulent, 226. 
 
 Eichwald on decomposition of 
 mucin, 281. 
 
 on peptones in pus, 273, 275. 
 
 in urine, ll8. 
 
 on separation of mucin, 271. 
 
 Elasticin, 37. 
 
 EUagic acid, 256. 
 
 Estimation of total nitrogen, 232. 
 
 Ewald on liydrochloric acid of 
 gastric juice, 182. 
 
 — — on pancreatic secretion, vari- 
 able nature of, 215. 
 
 on pUysiological and patholo- 
 gical fermentations, 21. 
 
 Extractives, Aqueous and al- 
 coliolic, 2. 
 
 in blood, 86. 
 
 in chyle and lymph, 101. 
 
 in dropsical fluids, 277, 282. 
 
 in fasces, 221. 
 
 in milk, 102. 
 
 Exudations, dropsical fluids, 275. 
 
 , hydatid cysts, 281. 
 
 , liquor amnii and allantoic 
 
 fluid, 279. 
 
 , murbid pus, 273. 
 
 , ovarian cysts, 279. 
 
 , reual cysts, 281. 
 
 , synovia, 279. 
 
 Feeces, Analyses of healthy, 221. 
 
 , Composition of, 221. 
 
 , Examination of in disease, 
 
 224. 
 
 , Meconium in, 223. 
 
 , Stercorin and excretin, 221. 
 
 Fats, neutral. Composition of, 31. 
 
 Fatty acids, 37. 
 
 degeneration. Acute, of liver, 
 
 261. 
 
 • — -, Infiltration of, 260. 
 
 , Nature of, 260. 
 
 — — , Separation of fatty mat- 
 ters in, 263. 
 
 - — matters, Digestion of, 194, 
 216. 
 
 , Estimation of, 85. 
 
 in bile, 205. 
 
 in blood, 85. 
 
 in bone, 285. 
 
 in chyle and lymph, 101. 
 
302 
 
 Clinical Chemistry. 
 
 Fatty matters in fseces, 224. 
 
 in milk, 102. 
 
 in pus, 273. 
 
 in urine, 165. 
 
 , Separation of, 263. 
 
 Feltz and Eitter on ammoniacal 
 decomposition of nrine, 116. 
 
 Fen wick. Dr., on sulpho-cyanate 
 of potassium, pathological im- 
 port of, 57. 
 
 Fermentations, Nature of, 17. 
 
 Ferments, Lactic acid, 225. 
 
 . , Organised, 19. 
 
 , Pepsin, 184. 
 
 , Ptyalin, 175. 
 
 ■ , Trypsin, 216. 
 
 , Unorganised or soluble, 20. 
 
 , Urea fermentation, 115. 
 
 , Teast, 153. 
 
 Fever, Chemical pathology of, 18. 
 
 Fibrin, Concretions of, 247, 256. 
 
 , Estimation of in blood, 71. 
 
 ferment, 35, 72. 
 
 in chyle and lymph, 101. 
 
 in urine, 147. 
 
 , Tests for, 36. 
 
 Fibrinogen in chyle andlymph,101. 
 
 m dropsical fluids, 277. 
 
 , presence in blood, 72. 
 
 ■ , Tests for, 34. 
 
 Fibrino-plastic, 34, 72, 84. 
 
 Fibrinous concretions, 247, 255. 
 
 Flatulent dyspepsia, 226. 
 
 Flatus, Nature of, 225. 
 
 Flint, Dr., on cholestersemia, 97, 
 205. 
 
 on stercorin, 221, 
 
 Formic acid, 38. 
 
 Frerichs on bile acids, injection 
 of, 204. 
 
 on peptones in urine, 148. 
 
 Fusible calculus. Analysis of, 248. 
 
 Gall stones, Analysis of, 253. 
 
 , Formation of, 251. 
 
 Gamgee, Professor, on mucoid 
 
 degeneration, nature of, 272. 
 Garrod, Dr., on gout, views re- 
 garding, 296. 
 on potash, diminution of, in 
 
 scurvy, 291. 
 ■ on sodium urate deposit on 
 
 joints, 258. 
 
 on uric acid in blood, 123. 
 
 Gases in stomach and intestines. 
 
 Nature of, 224. 
 Gaskell, Dr., on dilute acid and 
 
 alkaline solutions, influence on 
 
 circulation, 23, 69. 
 
 Gelatin, 37. 
 
 Gerhardt on peptones in urine, 
 148. 
 
 Globulin, Tests for, 33. 
 
 Glucose in blood, 88. 
 
 in urine. Detection and esti- 
 mation of, 150. 
 
 , Tests for, 29. 
 
 Glycerin-phosphoric acid in fatty 
 degeneration of brain, 262. 
 
 , Tests for, .32. 
 
 Glycocholic acid, 45. 
 
 Glycocin, 43. 
 
 Glycogen, Tests for, 31. 
 
 Glycogenic function of liver, 
 206. 
 
 GlycoUic acid, 41. 
 
 Gould, A. Pearce, on calculus con- 
 taining purulent fluid, 242. 
 
 Gout, Diminished alkalinity of 
 blood in, 295. 
 
 , relation to scurvy and 
 
 rheumatism, ,290. 
 
 , uric acid not necessarily 
 
 formed in excess, 296. 
 
 Gouty concretions. Tophi, 257. 
 
 Gowers, Dr. , on method of estima- 
 ting haemoglobin, 76. 
 
 Guanin, 60. 
 
 Hsematin, 81. 
 
 Hsematinuria from functional de- 
 rangement of liver, 214. 
 
 , Nature of, 161. 
 
 Hsematogenous jaundice, 196. 
 
 Hoematoidin, 83, 201. 
 
 Hasmatopopphyrin, 82. 
 
 Hsematuria, 160. 
 
 HEemic calculi, 287. 
 
 Hasmin, 82. 
 
 Hsemochromogen, 82. 
 
 Haemoglobin, Estimation of, 75. 
 
 , Tests for, 35. 
 
 Hammarsten on digestion of milt, 
 186. 
 
 Hay craft. Dr., on method of sepa 
 rating urea from blood, 87. 
 
 Hemi-albumose (Meissner's a pep- 
 tone), 187. 
 
 glutin, 269. 
 
 -peptone, 187. 
 
 Heninger, on peptones, composi- 
 tion of, 187. 
 
 Heptogenous jaundice, 195. 
 
 Hippocrates' views regarding cal- 
 culi, 235. 
 
 Hippuric acid. Character of, 46. 
 
 , in urine. Separation of, 
 
 139. 
 
Index. 
 
 303 
 
 HofTmnnn on feeding animals 
 
 with iicid salts, efTects of, 23. 
 Hofmeister on decomposition of 
 
 collason, 269. 
 
 ou liictosuria, 102. 
 
 ou peptoues iu urine, 119. 
 
 Holmes, Air. T., ou punctured 
 
 wound of ureter, 278. 
 Hoppe Seyler, on analyses of bile, 
 
 193. 
 on composition of bajmo- 
 
 jrlobin, 80. 
 Hyaliue dcj^encration, 266. 
 Hydatid cysts, Composition of, 
 
 281. 
 Hydrate of albuminate (peptone), 
 
 187. 
 Hydrocarbon radicals, 5. 
 Hydrocarbons, 4. 
 
 of the aromatic series, 6. 
 
 Hydrochloric acid, 54-. 
 
 , Estimation of, in urine, 
 
 137. 
 
 in gastric juice, 180. 
 
 Hydrofluoric acid, 55. 
 
 , Estimation of, in bones, 
 
 287. 
 Hydruria from increased or dimin- 
 ished mctamor[ihosis, 107. 
 Hypoxauthin in blood, 93. 
 
 in urine. Separation of, 168. 
 
 , Tests for, 50. 
 
 Indican in disease of pancreas, 
 218 
 
 in obstruction of small intes- 
 tines, 218. 
 
 in urine, 117. 
 
 , Nature of, 53. 
 
 Indigo, bow formed in sweat and 
 urine, 218. 
 
 in calculi, 247. 
 
 test for sugar, 154. 
 
 Indol, 53. 
 
 Inorganic constituents. Chemical 
 importance of, 22. 
 
 , conditions in which they 
 
 exist iu the body. 26. 
 
 , Distribution of, 25. 
 
 Inosite, 29. 
 
 Intestinal concretions, 255. 
 
 digestion, 219. 
 
 , Gases in, 224. 
 
 Intestine, Large, 220. 
 
 , small, Contents of, 219. 
 
 Invert sugar from cane sugar 
 in intestinal digestion, 219. 
 
 , Tests for, 29. 
 
 Iron, 65. 
 
 JafT6'8 reBcarclies into nature of 
 
 bile pigments, 200. 
 Jaundice, Hiomatogonous, 196. 
 
 , Heptogeuous, 195. 
 
 Johnson, Dr. George, on gouty 
 
 kidney, 297. 
 , , on picric acid test for 
 
 albumin, 14.3. 
 , , on for 
 
 sugar, 155. 
 , , on saccharometer, 157, 
 
 158. 
 Jones, Dr. Bence, on acidity of 
 
 urine after alkaline bicarbon- 
 
 ates. 111, 24-1. 
 , , on albumin in urine in 
 
 case of osteomalacia, 147. 
 
 , , on cystin, 166. 
 
 , , on xanthin, 167. 
 
 Klein on hyaline degeneration, 267. 
 
 KoUiker on corpora amylacea, 267. 
 
 Kreatin, Separation of, from blood 
 or muscles, 92. 
 
 , Tests for, 48. 
 
 Kreixtinin, 48. 
 — in urine, 140. 
 
 Krusenstern on injection of choles- 
 terin into veins of dogs, effects 
 of, 97. 
 
 Kuhne, Prof., on bile acids, action 
 on hoemoglobiu, 2i4. 
 
 , , on hippuric acid, where 
 
 formed, 139. 
 
 , , on peptones, classifica- 
 tion of, 187. 
 
 Lactic acid, 41. 
 
 , Consequences of excess 
 
 of, 227—229. 
 
 ferment, 20. 
 
 in intestines, 225. 
 
 in rickets, 2~8. 
 
 in scurvy, 294. 
 
 Lactose in milk, 103. 
 
 in urine, 102. 
 
 , Tests for, 30. 
 
 Lmvulose (invert sugar). Charac- 
 ters of, 29. 
 
 Lardaceiu, Nature of, 265. 
 
 , Separation of, 266. 
 
 , Tests for, 37. 
 
 Lardaceous degeneration, 26-t. 
 
 Lead, Separation of, from solid 
 tissues, 231. 
 
 in urine, 172. 
 
 Lecithin, Characters of, 47. 
 
 in blood, 86. 
 
304 
 
 Clinical Chemistry. 
 
 Lecithin in lymph and chyle, 
 
 101. 
 Legg, Dr. "Wictham, on action of 
 
 hile acids on heart, 203. 
 , , on bile acids, how de- 
 rived, 203. 
 , , on hile and its relation 
 
 to the formation of glycogen, 
 
 195. 
 , ,on absence of pigment in 
 
 urine after injection of bile acids, 
 
 204. 
 Leucic acid, 41. 
 Leucin, Characters of, 45. 
 
 in urine. Separation of, 168. 
 
 result of pancreatic digestion, 
 
 217. 
 Lime, Estimation of, 58. 
 Lithsemia, 211. 
 Liver, Functional derangement 
 
 of, 206. 
 Liversidge on starch ferment of 
 
 pancreatic juice, 216. 
 Loscar on feeding animals with 
 
 acids, effect of, 23, 68. 
 Lymph, 101. 
 
 Mackenzie, Dr. Stephen, on case 
 
 of chylous urine, 164. 
 , , on hyaline degeneration, 
 
 266. 
 MacMunn, Dr., on colouring 
 
 matter of urine, 116. 
 , of bile ; spectrum 
 
 of Pettenkoffer's test, 202. 
 , on spectrum of dropsical 
 
 fluid, 277. 
 , of ovarian fluids, 
 
 282. 
 JMagnesia, Calculation of, 286. 
 
 , Estimation of, 59. 
 
 , in bones, 283. 
 
 , in calculi, 248. 
 
 , , in faeces, 223. 
 
 Mahomet, Dr., on pre-albumi- 
 
 nuric stage of Bright's disease, 
 
 141. 
 Maly, E., on acidity of urine, how 
 
 caused, 183. 
 , on formation of acid in 
 
 gastric juice, 24, 54. 
 , on oxydation of bilirubin, 
 
 product of, 200. 
 Marrow of bone. Composition of, 
 
 284. 
 Maxwell, Dr., on case of puerperal 
 
 albuminuria, urea in, 120. 
 Meat, Eresh, why antiscorbutic, 
 
 293. 
 
 Meconic acid and sulpho-cyanate 
 of potassium, 57. 
 
 , importance of 
 
 distinguishing between them in 
 medico-legal inquiries, 175. 
 
 test for in opium poison- 
 ing, 192. 
 
 Meconium, 223. 
 
 Melanin, 117. 
 
 Mercury, Detection of, 177. 
 
 Metabolism increased tissue in 
 fever, 18. 
 
 in states of constitu- 
 tional disturbance, 213. 
 
 Metalbumin in ovarian cyst, 281. 
 
 Methsemoglobin, Characters of 
 78. 
 
 in urine, 162. 
 
 Meissner on nuclein in pus cells, 
 273. 
 
 Milk, Composition of, 101. 
 
 , Digestion of, 102, 186. 
 
 sugar in milk, 103. 
 
 • ■ — — in urine, 102. 
 
 , Tests for, 30. 
 
 Moore, Dr. Norman, on fossil 
 bones, 285. 
 
 Morbid exudations, dropsical 
 fluids, 275. 
 
 , hydatid cysts, 281. 
 
 , hydro - nephrotic cysts, 
 
 281. 
 
 , liquor amnii and allan- 
 toic fluid, 279. 
 
 , ovarian cysts, 279. 
 
 , pus, 273. 
 
 , synovia, 279. 
 
 Morochowitz on mucin and col- 
 lagen as embryonic state of 
 bones, 289. 
 
 Morphia, Detection of, in vomit, 
 192. 
 
 in tissues, 232. 
 
 , Tests for, 51. 
 
 Mucin in bile, 198. 
 
 in embryonic condition of 
 
 connective tissue, 268, and bone, 
 289. 
 
 in mucoid degeneration, 270. 
 
 in saliva, 175. 
 
 , relation to paralbumin, 280. 
 
 , Tests for, 36. 
 
 Mucoid degeneration. Changes in, 
 268. 
 
 , Professor Gamgee's view 
 
 of, 272. 
 
 Mucus distinguished from pus, 
 171, 273. 
 
 in urine, 170. 
 
Index. 
 
 305 
 
 Murcbisou, Dr. Cluirles, on 
 
 amouut of bile, 19 1. 
 , , ou doctriue of litlice- 
 
 mia, 212. 
 , , on fluid of hydatid 
 
 cysts, 281. 
 Murexide reaction, 49, 127, 246, 
 
 •IVi. 
 Murray, Dr., Newcastle, on soft- 
 water in treatment of calculi, 
 
 245. 
 Muscle, Separation of kreatin 
 
 from, 92. 
 Myeloplaxes, 284. 
 Myosin, Test for, 35. 
 Myxoedema, Nature of, 270. 
 Myiomata, Nature of, 271. 
 
 Naunym on bile acids in normal 
 
 urine, 20 J. 
 Neal, Dr., on fresh meat in scurvy, 
 
 292. 
 Neurin (cholin), 45. 
 Nitric acid, peculiar re-action with 
 
 urates, 127. 
 test for albumin in 
 
 urine, 143. 
 Nitrogen, Estimation of (soda 
 
 lime process), 232. 
 Nitrogenous compounds, 3. 
 
 , Enumeratioa of, 33, 43. 
 
 Non-nitrogenous compounds, 3. 
 
 , Enumeration of, 28, 87. 
 
 Nuclein, 273. 
 
 Oleic acid, 39. 
 
 , Separation of, from 
 
 stearic acid, 264. 
 
 Oliver, Dr., on indigo-carmine test 
 for glucose, 154. 
 
 Opium, 192. 
 
 Ord, Dr. W. M., on biliary calculi, 
 formation of, 251. 
 
 , , on disintegration of cal- 
 culi, 24]. 
 
 , , on indigo calculus, 247. 
 
 , , on molecular coales- 
 cence, 27. 
 
 , , on myxojdema, 270. 
 
 Organic acids, Separation of, from 
 mineral, 281. 
 
 Organised ferments, 19. 
 
 by yeast, 153. 
 
 , lactic acid fermentation, 
 
 225. 
 
 , urea fermentation, 115. 
 
 Osteomalacia, Albumin of urine 
 in, 187. 
 
 ■ , nature of changes, 289. 
 
 U 
 
 Osteomalacia, pj-obable relation to 
 
 myxcedeina, 289. 
 Oxalic acid as oxalate of lime in 
 
 urine, 128. 
 
 , Characters of, 41. 
 
 , Poisoning by, 190. 
 
 Ovarian cysts, Analvsis of, 282. 
 
 , Contents of, 279. 
 
 Oxydatiou in fevers, 18. 
 
 , Nature of, 17. 
 
 Oxygenated blood , Limited supply 
 
 of, co-use of diabetes, 207. 
 
 Pages injection of cholesterin 
 into veins of animals, effects of, 
 97. 
 
 Palmitic acid, 39. 
 
 . , Separation of, from 
 
 oleic acid, 2(54. 
 
 Palmitiu, Tests for, 32. 
 
 Pancreas, Disease of, 218. 
 
 , , Increase of indican in 
 
 lu-ine due to, 218. 
 
 , , relation to diabetes and 
 
 glycosm-ia, 211, 218. 
 
 Pancreatic calculi. Analysis of, 254. 
 
 iui e. Analysis of, unre- 
 liable, 215. 
 
 fat ferment, 20-216. 
 
 , Ferments of, 216. 
 
 , joint action with gastric 
 
 juice oil proteids, 217. 
 
 , Reaction of, 216. 
 
 Paracelsus, Calculi first analysed 
 by, 236. 
 
 Poraglobulin in urine, 147. 
 
 , Separation of, in blood, 84. 
 
 , Tests for, 34. 
 
 Paralbumin in ovarian cysts, 280. 
 
 Parkes, Professor, on acidity of 
 lu-ine after alkaline bicarbo- 
 nates. 111. 
 
 , , on chemical circulation 
 
 in body, 22. 
 
 , , on entrance and exit of 
 
 nitrogen, 23-4. 
 
 Pathological and physiological fer- 
 mentations, 17. 
 
 Pavy, Dr., on separation of 
 glucose from blood, 88. 
 
 , on views with regard to 
 
 the natiu-e of diabetes, 207. 
 
 Pepsin ferment, 20. 
 
 in gastric juice, 184. 
 
 Peptones, 36. 
 
 in pu-i, 273. 
 
 in urine, 1-48. 
 
 of pancreatic juice, 217. 
 
 of the gastric juice, 186. 
 
3o6 
 
 Clinical Chemistry. 
 
 Phenol (carbolic acid), 42. 
 Phosphatic diabetes, 107. 
 Phosphoric acid, 55. 
 
 , Estimation of, 131. 
 
 Picric acid test for albumin, 143. 
 
 for peptones, 148, 186. 
 
 -. for sugar, 155. 
 
 Planer on analysis of gases of 
 
 stomach and intestines, 225. 
 Poisons, antimony, 231. 
 
 , arsenic, 230. 
 
 , carbolic acid, 191. 
 
 , caustic alkalies, 191. 
 
 , Corrosive, 191. 
 
 , Detection of, in tissues and 
 
 viscera, 229. 
 
 , , in vomit, 190. 
 
 , hydrocyanic acid, 191. 
 
 , Lead, 172. 
 
 , meconic acid, 192. 
 
 , mercury, 177. 
 
 ■ , Metallic irritant, 191. 
 
 , morphia, 192, 232. 
 
 , opium, 192. 
 
 , oxalic acid, 190. 
 
 , phosphorus, 191. 
 
 , strychnine, 192, 232. 
 
 , sulphuric acid, 191. 
 
 , Veg-eto-alkaloid, 192. 
 
 ■ -, Volatile, 191. 
 
 Polarimeter, 158, 
 Polyuria, 107. 
 Potash, 60. 
 
 , Estimation of, 62. 
 
 Propionic acid, 39. 
 Prostatic calculi, 257. 
 Proteids, Constitution of, 14. 
 
 , Digestion of, 186, 217, 
 
 , General character of, 33. 
 
 in blood, 71, 84. 
 
 in chyle and lymph, 101. 
 
 in milk, 102. 
 
 in pancreatic juice, 215. 
 
 in urine, 140. 
 
 Ptoamines, 52. 
 Ptyalin in saliva, 175. 
 
 , nature of fernient, 20. 
 
 Pus, Analysis of, 273. 
 
 in urine, 170. 
 
 Pyo-cyanin and pyo-xanthin, 274. 
 
 Quekett, Professor, on calcium 
 oxalate in renal cell, 238. 
 
 Quincke on variations of hsemo- 
 globin in disease, 74. 
 
 Eainey, Professor, on molecular 
 
 coalescence, 26. 
 Ee-action of bile, 193. 
 
 Ee-action of blood, 67. 
 
 of dropsical fluids, 277. 
 
 of gastric juice, 179. 
 
 of hydatid cysts, 281. 
 
 of pancreatic juice, 216. 
 
 of pus, 273. 
 
 of saliva, 176. 
 
 of urine, 101. 
 
 Eees, Dr. Owen, on ammoniacal 
 
 reaction of urine. Causes of, 
 
 119. 
 
 • , — — , on gouty catarrh, 237. 
 
 Eenal cyst, Contents of, 281. 
 
 inadequacy, 109 — ^214. 
 
 Eheumatism, Discharge of acid 
 
 in, 298. 
 , relation to gout and scurvy, 
 
 290. 
 Eichet on acidity of gastric 
 
 .iuice, 180. 
 Eickets, hsamorrhagic form, pro- 
 bably related to scurvy, 289. 
 
 , Nature of changes in, 288. 
 
 , Views with regard to, 289. 
 
 Ringer, Dr., on potassium, 
 
 sodium, and ammonium salts, 
 
 action of, 23, 26. 
 Roberts, Dr. W., on fermentation 
 
 test for sugar, 153. 
 Role of inorganic constituents, 
 
 22. 
 
 Saccharose, Tests for, 30. 
 Salts in bile, 205. 
 
 in blood, 93. 
 
 • in bone, 286. 
 
 in chyle and lymph, 101. 
 
 in faeces, 223. 
 
 in gastric juice, 179. 
 
 in milk, 102. 
 
 in pancreatic juice, 215. 
 
 in pus, 975. 
 
 ■ in saliva, 175. 
 
 in urine, 127, 128, 131, 136, 137. 
 
 , Soluble and insoluble, 2. 
 
 , To estimate, 94. 
 
 Saliva, Composition of, 175. 
 
 , Detection of mercury in7177. 
 
 , quantities secreted, 176. 
 
 , Varieties of, 173. 
 
 Salivary calculi. Composition of, 
 
 256. 
 Salivation, 176. 
 Saponiflable fats. Characters of, 31. 
 
 • , Estimation of, 86. 
 
 in blood, 85. 
 
 in chyle and lymph, 101. 
 
 in fatty degeneration, 263. 
 
 Sarcosin, 45. 
 
Index. 
 
 307 
 
 Scheele, Uric acid discovered by, 
 236. 
 
 Scherer on discovery of inu-al- 
 bumin, 2S0. 
 
 on separation of mucin, 271. 
 
 Scheteli^ on paralbumin in reual 
 cysts, 281. 
 
 Schultzen and Eiess on peptones 
 in urine, 1-lS, 
 
 Scurvy, Diminution of alkaline 
 phosphates in, 2'J2. 
 
 , relation to gout and rheu- 
 matism, 290. 
 
 , views regarding changes of 
 
 blood, 291. 
 
 , vphy fresh meat and vege- 
 tables are anti-scorbutic, 293. 
 
 Seemou, Dr., on urine in riclvots, 
 288. 
 
 Semi-glutin, 2o9. 
 
 Sero-iuteiu, Sijactrum of, 277. 
 
 Serum, Blood, 84. 
 
 Silica, 6-t. 
 
 in bile, 206. 
 
 in bone, 285. 
 
 in foeces, 223. 
 
 Sodium salts, Estimation of, 62, 
 
 in bile, 205. 
 
 in blood, 94. 
 
 Solids, Estimation of, by evapora- 
 tion, 06. 
 
 , , by specific gravity, 
 
 106. 
 
 Soluble ferments, 19. 
 
 Specific gravity of bile, 193. 
 
 of blood, 66. 
 
 of dropsical fluids, 277. 
 
 of hydatid cysts, 2S1. 
 
 of ovarian cysts, 279. 
 
 of urine, 105. 
 
 Spectroscopic characters of chole- 
 telin in lu'ine, 116. 
 
 of dropsical fluid, 277. 
 
 of htemoglobin and its 
 
 compounds, 76. 
 
 — of ovarian cysts, 280. 
 
 of osydised bile pigments, 
 
 200. 
 
 of Petteukotfer's test for 
 
 bile acids, 203. 
 
 Staedeler on separation of mucin, 
 271. 
 
 Starch, Tests for, 30. 
 
 Stearic acid, 39. 
 
 , Separation of, from oleic 
 
 acid, 264. 
 
 Stearin, Tests for, 32. 
 
 Sterner on action of bile acids on 
 heart, 204. 
 
 Strychnine, Detection of, in 
 tissues, 232. 
 
 , , in vomit, 192. 
 
 , Tests for, ,51. 
 
 Succinic acid, 42. 
 Siiitar (»te Glucose). 
 Sulpho-cyauate of potassium, 57. 
 
 in saliva, 175. 
 
 Sulphur, unoxydisediu urine, 137. 
 Sulphuric acid, 56. 
 
 ■. Kstimation of, 137. 
 
 Synovia, 279. 
 Synthesis, 15. 
 Syntoniu, 36. 
 
 Taijpeiner on absorption of bile 
 at^ids, 203. 
 
 Taurin, 41. 
 
 Taurocholic acid, 44. 
 
 Tossier, Dr., on i)hosphatic dia- 
 betes, 107. 
 
 Tiil'enbach on glycosuria pro- 
 duced by artificial respiration, 
 209. 
 
 Topki, gouty concretions, 257. 
 
 Tyrosi-:, Character of, 46. 
 
 in urine. Separation of, 169, 
 
 UriBmia, 95. 
 
 Urates in calculi, 249. 
 
 in gouty tophi, 257. 
 
 in urine, 127. 
 
 Urea, Derivation of, 12. 
 
 , Estimation of, in iirine, 122. 
 
 ferment, 20. 
 
 , Relation of, to temperature, 
 
 19. 
 
 , Separation of, in blood, 87. 
 
 , Test for, 47. 
 
 •, Variation of, in disease, 118. 
 
 Uric acid calculi, 246. 
 
 , Clinical significance of 
 
 deposits of, 125. 
 
 , Estimation of, 127. 
 
 , Gouty concretions of, 
 
 257. 
 
 in blood, 93. 
 
 in urine, 123. 
 
 , Pathological relations 
 
 of, 123. 
 
 ■ -, Test for, 48. 
 
 Urine, Abnormal constituents of, 
 
 140. 
 , Alkaline and earthy phos- 
 
 Ijhates in, 131. 
 and bile. Test for pigment 
 
 and acids in, 163. 
 
 , Blood as hoematuria in, 160. 
 
 , as hsematiimria in, 161. 
 
3o8 
 
 Cl I NIC a l C hem is TR J ', 
 
 Urine, CaJoiuxn oxalate iu, 128. 
 
 , CbloriJes iu, 136. 
 
 , chyle in. Analyses of, 16j. 
 
 , Clinical examination of, IW. 
 
 , Cystiu in, 166. 
 
 , Estimutiou of Lydrocbloric 
 
 ucid iu, 137. 
 , of phosphoric acid in, 
 
 135. 
 
 , of Bulpliiiric acid in, 138. 
 
 , Pibriu clots iu, 1+7. 
 
 , hippuric acid in, Separation 
 
 of, lay. 
 
 , Hyjjoxanthin in, 168. 
 
 , Kreutinin in, 140. 
 
 , \etiA, Detection of, in, 172. 
 
 — , Louciu in, 168. 
 
 , MucuH and pus iu. 170. 
 
 , Piiraslolniliii iu, 1+7. 
 
 , peptones in, To Beparntc, 
 
 \Mi. 
 
 piemcut, 116. 
 
 , Pro-peptoae in, 147. 
 
 rv-actiou, K<3. 
 
 , sero-olbumin in, TesLt for, 
 
 , Eittimation of, 145. 
 
 , Spociflc irmvitr of, 106. 
 
 , Su>{nr-t«iit« (or, 150. 
 
 , , Ettinuttiou of, by copper, 
 
 m. 
 
 , , , by fcrmeutAtiou, 
 
 153. 
 , , , by JohoBon'fl 
 
 Mtocbaromoter, 1S5. 
 , , , br poUrimetry, 
 
 1.^. 
 
 , SulpbatM in, 137. 
 
 , TmU for blood in, 162. 
 
 .TyixMiu in, ItiS. 
 
 , ur«* in, Eniiniation of, 122. 
 
 , ——, vanAtioux in disease, 
 
 118. 
 
 Urine. Variation in reaction of, 
 in disease, 112. 
 
 , Xauthin iu, 167. 
 
 Urobilin, Formation of, 200. 
 
 iu urine, 117. 
 
 Urostealith, 217. 
 
 Valeric acid, 39. 
 
 Vaso-niotor i>aralysis in diabetes, 
 209. 
 
 ^— may be induced by dim- 
 inished alkaline reaction ot 
 blood, 211. 
 
 Vegretables, Fresh, why anti- 
 scorbutic. 293. 
 
 Vesreto-alkoloids, Separation of,' 
 from tissues, 231. 
 
 , Tests for, 51. 
 
 Voit.uitroKeu, Estimation of, 232. 
 
 Volatile poisons, Dotoctiou of, IHl. 
 
 Vomited matters, Detection of 
 poisons in, l!>0. 
 
 , Determination of 
 
 lunoant and nature of acid iu, 
 188. 
 
 Williams, Dr. John, on liquor 
 
 ainuii of diabetic patient, 2(.M>. 
 , , on reaction of sul- 
 
 jiburic acid and iodine with 
 
 lardAceiu, 266. 
 , , on venesection in cost" 
 
 of puerjKsral albuminuria, 97. 
 
 Xanthin calculi. 247. 
 
 , ChanictiT ..f, 50. 
 
 in urine, 167. 
 
 Xautboprotoic roaction absent in 
 
 true peptones, 1^7. 
 of proteids geueruUy, 
 
 S3. 
 
 Yout torment, 20. 
 
 CAA8ELL AVDOOUPAVr, UMITKD, BKLLE SAUVAOt: WORKS, LONDON, K C. 
 
QP514 
 Ralfe 
 Clinical chemistry 
 
 R13 
 
ri 
 
 4