nil';' lii'' l!lll'll!llllil!ll|i|llllll!llilll!lllllill!lill'"|l liljMhh! IH hiii: BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Mtnvu W, Sage 1891 ,P.:kW?'7-0 -..wXn]. iom.iLo... RETURN TO ALBERT R. MANN LIBRARY ITHACA, N. Y. DATE DUE DltC 1f JUUKj j.(; 1971 mill i Wl r .r-r MIV 1 3 m(i interlioi w^ 1 GAYLORD PRINTED IN U.S.A. Cornell University Library TX 553.U7H17 1904 The purin bodies of food stuffs and the 3 1924 003 549 809 Cornell University Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003549809 THE PURIN BODIES OF FOOD STUFFS THE PURIN BODIES OF FOOD STUFFS And the Role of Uric Acid in Health and Disease Xl'' BY I. Walker Hall, M.D. Assistant Lecturer and Demonstrator in Pathology, the Owens College, formerly Senior Demonstrator in Physiology at the Owens College, the Victoria University of Manchester; Hon. Pathologist to the Salford Royal Hospital. Second Edition (Revised) P. BLAKISTON'S SON & CO. PHILADELPHIA 1909 -jH--^/ PREFACE TO SECOND EDITION. To meet a demand, instead of a simple reprint, the first issue has been revissd, several portions re-written, the results of recent investigations included, the literature brought up to date, and new estimations, etc., added. A chapter on the action oi drugs upon purin excretion now appears, and an index and some tables of analytical methods are appended. I have to express my thanks for the interest manifested in the first edition, and to apologise for the necessarily brief replies to many foreign and English correspondents. Several blocks have been lent to me by the Editor of the "Practitioner," and it is a pleasure to here record my appreciation and thanks. 1903. INTRODUCTION. My object in undertaking the following investigation was to obtain further information as to the action of purin bodies and their metabolism, and to discover some means whereby the early pathological changes in certain metabolic disorders may be detected. In endeavouring to solve these problems, I have made estimations of the purin bodies present in the more common foodstuffs, and studied their specific effects upon the metabolic processes in animals and man, when they are introduced into the body subcutaneously or taken by the mouth. Were it possible to recognise the first stages of the altered functions, the application of preventive and remedial measures would soon follow. The importance of the subject is emphasised by our knowledge of the secondary results of imperfectly katabolised substances upon the vascular and excretory systems. It has been aptly remarked that two-thirds of the cases of cardiac strain in the second half of life present a history of perverted metabolism. I desire to specially express my indebtedness to Professor Stirling, Manchester, Geheimrath Hering and Professor Sieg- fried, Leipzig, Professors Johansson and Holmgren, Stockholm, for permission to work in their laboratories. My thanks are also due to them, as well as to Professor Santesson, Stockholm, and Dr. Burian, Leipzig, for their kindly interest and encourage- ment in an enquiry, which although by no means fulfilling the projected aims, will, I hope, furnish some basis for further work in a similar direction. July, 1902. CONTENTS. CHAPTER PAGE 1 . The Chemistry and Physiology of Food Purins 1 1 2. The Methods of Estimation . 24 3. The Quantitative Estimation of Purins 39 a. in Meats 39 b. in Vegetables 44 c. in Beverages 47 4. The Actions of Food Purins 50 a. Alimentary System : 50 b. Circulatory ,, 52 c. Respiratory „ 55 d. Genito-urinary „ 56 e. Nervous „ 58 /. Skeletal „ 58 5. The Action of Food Purins on the Elimination of CG„ 62 6. The Histological Eflfects of Continued Daily Injection of Food Purins 70 7. The Fate of Food Purins in Metabolism - 79 a. Meats 85 b. Vegetables 89 c. Beer and Alcohol 93 d. The Fsecal Purins 99 e. The Rate of Purin Elimination - 105 /. The Exogenous Purin-remainder 107 8. The Pathology of the Purin bodies 120 9. The Fate of Drugs upon the Elimination of Purin Bodies 131 10. The Estimation of Urinary Purins 140 11. Summary 155 12. Literature 159 13. Appendix 181 TABLES AND ILLUSTEATIONS. PAGE 1. The Earlier Estimations of Xanthins in Organs 21 2. Later Estimations of Purins in Meats 22 3. Comparison of the Purin Estimations 23 4. Estimations of Purins in Meats 40 5. The " Free " and " Bound " Purins in Meats 42 6. The Total and Extractive Nitrogen of Meats 43 7. Estimations of Purins in Vegetables 46 8. „ „ Beverages 48 9. The Effect of Purins upon COo Elimination 67 10. The Absorption and Elimination of Hypoxanthin 67 11. ,, „ ,, of Uric Acid 67 12. Blood Pressures, after Injection of Purin Bodies - 71 13. The Endogenous Factor 86 14. The Metabolism of Foodstuff Purins 88 15. „ „ Vegetable „ W.H. 91 16. „ „ „ „ N. 91 17. „ „ „ „ M. 91 18. ,, „ Beverage „ 97 19. The Purins of the Feeces - 102 20. The Maintenance of Nitrogenous Equilibrium 10-5 21. The Endogenous Purin in Relation to Body-weight 118 22. The Estimation of Urinary Purins by the Purinometer 147 23. Scheme of the Cleavage of Nucleins - 16 24. Normal Liver of Eabbit 76 25. Rabbit's Liver after Injection of Hypoxanthin 76 26. Exogenous Nucleins 111 27. Endogenous Nucleins, Origin and Fate 115 28. Endogenous Purins in Disease 126 29. The Purinometer 154 CHAPTER I. The Chemistry and Physiology of Food Pdrins. Since Kossel estaMislied tlie close chemical connec- tion between nucleins and the xanthin bodies, many experiments have been made in order to determine the precise changes which occur during the meta- bolism of these substances in the animal organism. Few investigations, however, have been more per- tinent and conclusive than the systematic enquiries which have been made into the sources of uric acid and which have ultimately differentiated the several factors in its formation. Of these factors the group named endogenous still compels the acknowledge- ment of its unknown origin, but the other, the exogenous, appears to be directly dependent upon the nucleins and xanthins contained in the ingesta, or in other words, upon the amount of purin bodies present in the daily diet. The term " purin " has been applied by E. Fischer to a nucleus C5N4, and hence all bodies constructed upon such a base may be included under this name. The purin bodies of ordinary occurrence are Hypoxanthin, C5H4N4O 1 — 6 oxypurin, Xanthin, C5H4N4O2, 2 — 6 oxypurin, Uric acid CJlJ^^Oa, 3-oxypurin, Guanin, CgHgNgO 2 amino-purin, Adenin, CsHjNs, 6 — amino-purin, Caffein C5HN4O3 (CH3)3 tri-methyl-oxypurin, and Theobromin, C5H2N4O2 (CHa)^, di-methyl-oxypurin. 12 THE PURIN BODIES Although current text-books treat the chemistry of the individual purins somewhat exhaustively, it is necessary to state some of the principal facts which underlie their group reactions in order to delineate the several phases of niiclein metabolism. The purin compounds crystallise easily, are more or less soluble in the usual solvents, and can now be oxidised and reduced. Hypoxantliin yields small crystalline scales with sharpened extremities almost like grains of wheat. Xanthin may be distinguished by its thin, flat, glistening rhombic plates, Giianin by small prismatic crystals or amorphous masses, Adenin by long needle-shaped prisms, and U)-ic acid by rhombic plates. Rarer forms have been demon- strated by variations in the media and rapidity of crystallisation. Their solubilities present the following remarkable differences : — Hypoxanthin. Xanthin. Adenin. Uric Acid. Guanin. Water: Cold 1:300 1:13000 1 : 1086 1 : 16000 Insoluble Hot 1:78 1:1.300 — i:i600 Alkalies : Weak. Soluble Soluble Soluble Soluble Slightly Soluble Acids : ,, ,, „ Insoluble Soluble By reduction of uric acid with chloroform in a sodium solution, a;i2?) i/im first appears, and is followed by hypoxanthin; the latter finally splits up into CO,, NH3 and cyanamid bodies. By oxidation with ozone, cupric oxide, or potassium permanganate in neutral or alkaline solution, uric acid yields allantoin CiHgN^Oa and CO2. On the addition of nitric acid. OF FOOD STUFFS 13 or potassium. cUorate and liydrocliloric acid, uric acid breaks up into alloxan, C3H3N2O4 and urea, and by further oxidation, urea and oxalic acid are obtained, with parabanic acid, C3H2N2O3, and oxal- iiric acid, C3H4N2O4, as intermediate products. In ammoniacal copper solutions in the presence of air, uric acid yields oxalic acid and urea, and when mammalian blood is added to a solution of uric acid, and allowed to stand for several days at 20 — 35° C, the uric acid entirely disappears, and urea, oxalic acid, NH3 and CO3 are found to be present. When nitrous acid is added to guanin (C5H5N"50) xanthin is formed; adenin (C5H5N5), plus nitrous acid, yields hypoxanthin, and by pancreatic digestion, hypoxanthin, xanthin and guanin are broken up into simpler bodies, but hypoxanthin is the least altered. As regards their cleavage products : — Uric Acid + HCl heated to 160°— 170° C = glycoooll, NH3 and COj. Adenin + HC1 heated to 180° C = glyoocoll, NH3 and CO2 and formic acid. Xanthin + HC1 heated to 200° C=glycocoll, NH3 and CO^ and formic acid. Guanin + HC1 warmed =glycocoll, NH3 and COg and formic acid. From a synthetic standpoint the purin bodies are exceedingly interesting. About twelve different combinations of the purin nucleus are known to exist in nature, but not less than 146 have been produced in the laboratory. Caffein and theobromin 14 THE PDRIN BODIES are largely used as medicaments for their stimula- tive and diuretic properties, and it is possible that in the near future these may be made synthetically. Trichlorpurin, obtained by the action of phos- phorous chloride upon uric acid, occupies a position midway between uric acid and the methyl xanthins, caffein, theobromin and theophyllin. Emil Fischer, in his lucid and interesting address given in Stock- holm in November, 1902, after the distribution of the Nobel prizes, draws a picture of the time when the present coffee adulterants — chicory and coffee- siirrogate — will be superseded by synthetically made caffein, and suggests a period when coffee beans and their roasting will be unnecessary, since the solution of a small powder in hot water will give a well- flavoured refreshing drink at a much lower cost and with much less trouble than the present condi- tions necessitate. Through their afiinity for silver and copper salts, the purin bodies may be fully precipitated by silver nitrate in ammoniacal solutions, or by cuprous oxide in the presence of sodium bisulphite. The separation ■of the several purins, although somewhat tedious, presents no special difficulties. The relation of these bodies to one another will be seen by their structural formulae. OF FOOD STUFFS 15 I ! ! 1 >c« ^N— ■'C— NV Purin nucleus. HN —CO / ! CH C— NH> \ II )CH HN — C — N^/ Hypoxanthin (Monoxy purin). HN — CO / I CO C— NH^ \ II )CH HN — C — N* Xanthin (Dioxy purin). HN — CO / I CO C— NH. \ II )co HN — C— NH/ Uric acid (Trioxy purin). N =CH I I C C— NH II II '^CH N — C — N^ Purin. HN — CO / I C(NH) C— NH> \ II )CH HN — C — N^/ Guanin (2 amino purin). N = C — NH., I C — NH., C — N'' Adenin (6 amino purin). CO I CO C — N< CH \ N CH^.N > CH CH,, ;0H CHg N — C — N/ CafFein. Prom the above it would appear tliat purin consists of two urea radicles linked by a chain of carbon atoms, although it would be more correct to state that it is formed by the union of alloxan with one radicle of urea. Hence the term " alloxuric bodies " has been also applied to these substances. 16 THE PURIN BODIES The piirin bodies exist eitter in a free state or combined with albumin in the form of nucleic acid. Hypoxanthin and xanthin occur in muscle extracts or are obtained by treating cell nucleins with H2SO4. Adenin is yielded chiefly by the decomposition of the nucleic acid present in thymus and guanin by the nuclein prepared from pancreas. The nucleins contain albumin and a carbohydrate (pentose or xylose) in addition to the nucleic acid. The following scheme shows the probable course of cleavage : — Nucleo-Proteid. Nuclein. Nucleic Acid Albumin. K»,,",°,5^P!0i) Phosahoricacid. ^^^f'ff „ ^^^^HyPOXANTHIN Carbohydrate Nucleotin \(^s"s"t. 1 /c.H.N.O \K -phosphoncAcid 1 1 eaminopunnj ( Aiomirpurin) ^ Guanin ^-^^ | Uric Acid combination (Tnoiypunn CiH^N^O^) r Allantoin, (C,N,H,0,) Urea Vricacid (CsH^n^o,) OF FOOD STUFFS 17 The daily " wear and tear " or metabolism of cell constituents leads to the prodnction of a certain amount of purin bodies. Whether this occurs in the vegetable, animal or human organism, these sub- stances constitute the " endogenous " purins of the excreta. When tissues containing nucleins or free purins are eaten by lower animals or by man, the " endogenous " purins of the food ingested become " exogenous " to the system which absorbs them. As " endogenous " purins are practically waste products on their way to excretion, so when they become " exogenous " to another organism, they have little nutritive value and demand early and rapid elimination. This is generally effected by the oxida- tion of the oxy-purins, hypoxanthin and xanthin, to uric acid, and then the purin ring or chain in the uric acid is in the liver partially split off and a portion of the uric acid execreted as urea. The course followed in the case of the nucleins is not quite clear, as a smaller percentage appears in the urine as uric acid. Amongst foodstuffs, with the exception of uric acid, the purin bodies are widely distributed. They exist in all forms of meat extracts, in the flesh meats of ordinary consumption, and in larger quantities in the glandular organs — thymus, pancreas, etc. In lesser amount they occur in many vegetables, as oats, potato, and sugar beet. Schultze and Bossard found them also present in the leaves and bark of certain trees, in young grass, and oat straw; in other plants they found a body vemin which, on the addition of HCL, yielded a guanin. Bethe states that the scales 18 THE PURIN BODIES of Alhurnus lucidus consist largely of guanin. Griffiths found that the pigment of Dienychylus riridescens yielded uric acid when treated with HCl, and Hopkins observed that uric acid formed the basis of the white pigment of Pierida brasxica. That the purins were first discovered in urinary calculi, and occur as regular constituents of human urine and faeces, are facts, which although well-known, may yet be cited, because they to a great extent express the chemical activity of individual meta- bolism, and the normal or abnormal conditions of the organic functions. Before the connection between the purins and nucleins was known, the former were the cause of much controversy. Lehmann, Proust and many others investigated their effect upon the heart and circulation. Thudicum, in England, issued a treatise on the " origin, nature and uses of Liebig's extract " (1869), and the subject became one of distinctly polemic interest for both France and German scientists. Their conclusions attached little harmful influence to these bodies, but Gaucher, in 1886, observed degeneration of the convoluted tubule cells of the kidney after the injection of hypoxanthin, and von ISToorden, in 1896, remarked upon their constant presence in the usual articles of diet, and the harmf \il influence their deficient excretion might exert upon the kidneys and general tissues. He considered it a matter for regret, however, that no data existed as to the purin contents of the various meats of common consumption, for quantitative determinations would have been of value in regard to the much-discussed OF FOOD STUFFS 19 question of " wliite or dark meats " — veal, cliicken, beef, mutton — in gout and kidney diseases, during general convalescence, and in disorders of the stomacli and intestinal mucous membranes. Senator and von Leyden state that the dark meats | contain a larger amount of extractives than the lighter varieties, and hence are more irritating to the kidneys during excretion. Saundby, West, and Yeo condemn soups and meat extracts on account of their " extractives." Dyce Duckworth only allows the use of red meats once a day in nephritis; von Noorden permits their use in similar quantities to the white sorts, and Yeo prefers white meats alone; Dickinson advises light animal broths in nephritis ; Luff is dis- inclined to their use in acute gouty attacks, but recommends either beef, mutton, chicken, turkey, pheasant or calf's sweetbread once a day during the intervals. In order to obtain some tangible reasons for these opinions, Oifer and Rosenqvist, in 1899, analysed certain meat foods, and were led to the conclusion that the variations in the amount of extractives contained in white and red meats were so slight that any theory as to their degree of irritative action, based upon such differences, could not be well founded. Their methods were not, however, free from objections, the varieties of foods they examined were but few, and even if their results were correct, it is obvious that the investigation calls for much more consideration than the simple analytical differences of the ingesta. A deeper interest, however, centres in the specific 20 THE PURIN BODIES actions of food purins upon the various systems of the body, and their behaviour during the processes of metabolism. For such aspects are important in their relation to the construction of children's dietaries in connection with the evolution of the fermentative and chemical functions of their metabolic organs, and the tissue changes in certain diatheses. Not less significant are the action of purins in regard to the cessation of the processes of growth, the maintenance of adult life, and the gradual decline of bodily activities. Further, the individuality of '' body "' (Korper) chemistry is an- other factor which investigations upon these bodies has emphasised, and hence there is a need for some methods by which individual patients may be more accessible for the precise determination of their purin or nuclein metabolism. The existent analyses of the purin-holding contents of food are best given in tabular form. They are but few in number. Hutchinson, in 1900, writes : "As regards the amount of extractives, but few data are available," and their absence from scientific literature has been frequently deplored. Jerome, in his admirable paper upon the relations between variations in the food and uric acid excretions, states that the alloxur-nitrogen of the food was not deter- mined, and in the absence of precise knowledge as to the quantity of alloxur-nitrogen in both the food and fseces, certain deductions were impossible. Naturally, such estimations, together with those of the urinary purin, make too much demand upon the energy and time of one worker, but had any reliable OF FOOD STUFFS «21 food purin analyses been then available, from Jerome we should probably have learned of the " endogenous " and " exogenous" factors of uric acid iormation, instead of noting their appearance several years later in a language other than our own. Table I. The Earlier Estimations of Xanthine in Food, Hypoxanthin % Xauthin % Calculated as Purin Nitrogen % Beef ... . . 0-022 ... 0-008 Strecker 0-027 0-016 ... 0-018 „ , ... 0-006 Neubauer 0-156 ... 0-062 Stadeler Chicken . 0-073 0-129 ... 0-0291 „ , ... 0051 1^°^^^' _.. Fowl ... . ... 0-070 ... 0-028~> „ „ Q.Q26| Hofimann Dove ... . . 0-037 ... 0-014' 0-090 ... 0-036 I Demant 0-107 ... 0-048 0-120 ... 0-060 Kossel Liver — ox . .. 0-011 ... 0-048 Stadeler dog . ox . .. 0-082 . 0-053 ... 00331 -rr , ... 0-021 }^°^^^1 22 THE PUEIN BODIES Table II. Later Estimations of " Pijrins " in Pood. purin nitrogen. Calculated as purin %. Liver — dog- .. 0-175 ... 0-4375 calf .. 0-123 ... 0-3575\ ... 0-1225/ Beef ... ... 0-053 .. 0-030 ... 0-0700 „ .. 0-046 ... 0-1150 „ steak .. 0-071 ... 0-1775 Veal ... .. 0-057 ... 0-1325 ,, .. 0-030 ... 0-0750 Pork ... .. 0-031 ... 0-0775 Mutton .. 0-034 ... 0-0850 Ham . . . .. 0-063 ... 0-1575 J, — .. 0-052 ... 0-1300 Fowl ... .. 0-030 ... 0-0760 Table III. Kossel Burian und Schur Kossel Offer und Eosenqvist )> »» )j Burian und Schur OSer und Eosenqvist 5J )* >y J> 3J 33 Burian und Schur OfJer und Eosenqvist Comparison of the Later Estimations. Burian und Schur. Purin N % Purin % Offer und Kosenq-vis Purin N X Purin % Beef ... 0-063 ... 0-1325 . .. 0-046 ... 0-1150 Veal ... 0-057 ... 0-1425 . .. 0-030 ... 0-0750 Ham ... 0-063 ... 0-1576 . .. 0-052 ... 0-1300 Yariations in the metliods of extraction and estimation perhaps account for these marked differences. The quantities of purins found have OF FOOD STUFFS 23 gracUially increased from the earlier to the later investigators, but even were it possible to strike an average between the widely different figures of the later results, the analyses only include a few of the substances used as national food. Any estimations of such constituents should, however, be first approached from the standpoint whence the present results have diverged, so that a critical study of the methods employed becomes a necessary preliminary to the further consideration of the substances them- selves. 24 THE PURIN BODIES CHAPTER II. The Methods of Extraction and Estimation. As the " purins " may exist in weak combinatioii witli certain proteid substances, or their precipitation be hindered by the presence of albuminous or phos- phorus-holding bodies, one object of the methods employed has been to remove all proteids from the solution containing the purins, before attempting to obtain the latter as metallic compounds. The follow- ing papers contain the principal processes and modifications that have been used : — Strecker, " ' Liebig's ' Annalen," 108, 1858. Neubauer, " Zeit. fiir Analy. Chemie.," 16, 1867. Salkowski, " ' Virchow's' Archiv.," Bd. 50, S. 174, 1870. Salomon, " Zeit. fiir Phys. Chemie.," Bd. 2, S. 65, 1879. Demant, " Zeit. fiir Phys. Chemie.," Bd. 3, S. 387, 1879. Kossel, " Zeit. fiir Phys. Chemie.," Bd. 7, 8, 1883. Stadthagen, " ' Virchow's ' Archiv.," 109, S. 399, 1887. Burian und Sohur, " Zeit. fiir Phys. Chemie.," Bd. 23, S. 60, 1898. Offer und Rosenqvist, " Berlin, klin. Wooh.," S. 938, 1899. Burian und Sohur, " ' Pfliiger's ' Archiv.," 80, S. 24, 1900. The earlier of these workers extracted the minced- up substance with water at 50° C. for several hours, removed the proteids with lead acetate, and then pre- OF FOOD STUFFS 25 cipitated the xanthins by silver salts, and crystallised them from strong nitric acid soliitions. Kossel observed that extraction with a dilute solution of sulphiiric acid accelerated the process and increased the yield, and so he boiled the organs in weak H2SO4 for some hours, then neutralised, removed the sulphate by baryta, the baryta by CO2, and precipit- ated the purins by ammoniacal solution of silver nitrate. When, however, albumin is boiled for a long time in acid solution, small quantities of albumose are formed, and these enter into combina- tion with the purin bodies, or in some way hinder their precipitation. Thus it became necessary to remove these from the solution. Kossel employed lead acetate for this purpose ; Stadthagen used a double volume of 95 per cent, alcohol, as he found that with the lead acetate method ^/26th of the total purin was lost. Burian and Schur, after removal of the albumins, precipitated the purins by ammoniacal silver nitrate solution in the presence of albumoses ; from the filtrate they removed the silver by SH2, dispelled the latter by heat, and precipitated the albumoses by a mixture of equal parts of basic and lead acetate, then re-precipitated with silver and added the amount of the resultant purin to that of the former. The length of this process and the role of the albumoses in preventing complete precipita- tion, provided the cause for my endeavours to over- come these difficulties. In selecting precipitants, it was necessary to bear in mind the ultimate introduction of silver salts. Devoto's method for the separation of proteids by a 23 THE PURIN BODIES saturated solution of ammonium sulphate seemed worth a trial. The albumoses were not, however, entirely removed, and I found that the presence of (NH4)2S04 hindered the purin precipitation. For both these reasons, the method was inapplicable. Tannic acid. It was not easy to obtain this reagent free from nitrogen, so control estimations were always necessary. To entirely remove it from the solutions before using the ammoniacal silver was also a matter of considerable difl&culty. The pre- cipitates produced, neither fell nor filtered easily, vmtil the solution had stood for some days. An endeavour to hasten the process by the centrifuge was only partially successful. Although the remain- ing albumins were efficiently removed, the albumoses and gelatines were still suspended as flocculent flakes. An extract from boiled codfish, to which tannic acid was added on xfovember 6th, 1900, after filtration, gave the following results by Kjeldahl's process: — (1) After boiling in weak acetio acid solution and filtering, 0,0980 % N., estimated Xovember 6th, 1900. (2) After boiling in weak acetic acid solution and filtering 0,0910 % N., estimated November 6th, 1900. (3) After adding tannic acid, 0,0908 %, estimated November 26th, 1900. (4) After adding tannic acid, 0,0336 %, estimated June 20th, 1901. Almcns solution of 4gm. tannic acid, 8cc. of 25 per cent, acetic acid, and 190cc. of 50 per cent, alcohol OF FOOD STUFFS 27 was tried, but as the precipitates were soluble in excess of tbe reagent, it was not entirely satisfactory. Stadtliagcn used two volumes of 95 per cent, alcohol, but even if this process were free from objections, the high government duty upon this scientific necessity renders the process too expensive for continuous use in England. Zinc sid-phate, according to Baiimann, Bonner and Zuntz, precipitates albumoses as perfectly as satur- ated ammonium sulphate solution. They add Ice. of 25 per cent. H2SO4 to each 50cc. of the albumose solution, and then saturate it with zinc sulphate. The precipitate contains NH3, tyrosin, small amounts of kreatin and sometimes traces of leucin, in addition to that of the albumoses, but the flesh bases are said to be untouched. The method does not admit of easy application to the estimation of purins, as the presence of zinc certainly hinders their precipitation, and its hydroxide is not too easy to dissolve. An extract of raw codfish, which gave a good biuret reaction for albumose. By ordinary methods yielded 0"2864 % purin N. After ZnS04 precipitation yielded 0-1081 An extract of rabbits' muscles By ordinary methods yielded 0'1536 „ After ZnSO^ ppt., removal of the Zinc by SH, and overplus of NH^OH yielded 0-1523 The removal of the zinc by SH2 appeared to render the method somewhat more precise, but its details were difficult to modify. 28 THE PURIN BODIES Bechmanns precipitation of proteids by formalde- hyde was unfortunately quite inapplicable to the purpose in view. Kriiger and "WulfE's copper process precipitates other bodies than the purins, but yet, as many observers have shown, does not always com- pletely precipitate the xanthins. Hence, although Malfatti found it reliable, it was not considered a safe method to employ. In the earlier days of the enquiry it was used as a control, but its variable results led to its discontinuance. As gelatinous substances are present in extracts of cooked meats, it was necessary to provide for their removal. Salkowski found that flesh treated with water at a temperature not exceeding 30°C., yields no gelatine ; but to obtain complete cleavage of the nucleins the minced meat must be boiled for some hours. The alcoholic method for the precipitation of gelatine is not now considered reliable, so that on the few occasions when a cold extract of meat was desired, the bromine process of Allen and Searle was employed. The results of my experience gave so little satis- faction that I decided to proceed upon the lines of Burian and Schur's later method, modifying it as occasion arose. When I had used it for several months His and Hagen published a critical summary of the methods available for the estimation of purin bodies in animal organs. Their results led them to conclude that in the direct and correctur method of Burian and Schur, the first precipitate contained albumose as well as silver-pu.rin, and hence gave a too high nitrogen result : that the albumose could OF FOOD STUFFS 29 be removed by zinc sulphate or ammoniura sulphate, but that purins were carried down with the albumose precipitate, and lessened the total amount of purin- nitrogen. This confirmed my own previous results. They also considered that no reliable method for the estimation of food purins existed, for the lead acetate method gave a loss, and although this was nearly constant in the case of beef, with rabbit flesh and other meats containing methylxanthins, the yield of nuclein substances was inconstant. It became imperative, therefore, to re-examine the method I had selected. Elsewhere I have stated the detailed results of such investigation made in conjunction with Dr. Burian (Zeit. f. Physiolog. Chemie., p. •336 — 396, Bd. 38) of which the following is a brief summary. From a critical standpoint it appeared necessary to answer the following questions : — (1) Does the precipitate contain any nitrogenous bodies other than purins, and what is its precise chemical constitution? (2) "What conditions ailect the total purin pre- cipitation ? (3) What further modifications should be made? To fully elucidate these points each step of the process was examined separately. (1) Inf,uence of the quantity of the solution and the length of the boiling. The experimental results showed that the dilution of the solution, and the duration of boiling (above 12 hours) do not materially alter the total amount of purin obtained, but that in dilute solu- tions the first precipitate is small, and the second or " correctur" precipitate is larger, and if the solutions 30 THE PURIX BODIES are evaporated down to 200 — 300cc. before the animoniacal silver nitrate is added, the " correctur " precipitate is so small that it may be almost neglected. The addition of barium hydrate solution. The figures obtained from estimations of glandular and muscular tissues show that when the original solution is made weakly alkaline by barium hydrate, more albumose is present after filtration than when it is made strongly alkaline ; hence after weak barium alkalinity there is a greater hindrance to the purin precipitation, and the " correctur " or second pre- cipitate contains the greater proportion of the purin. Additionally, with a marked surplus of Ba(OH)„, the introduction of COo produces its more complete removal. The evaporation of the solution before silver precipitation. Comparative estimations of the purin- contents of solutions evaporated in neutral and acid media, showed that unless marked acidity is main- tained, upwards of 50 per cent, of the total purins are decomposed and lost. When the solutions were very concentrated, it was found that some of the less soluble purins formed small insoluble masses, whose solution necessitated the addition of sodium hydrate and sodium carbonate for the removal of any remaining barium compounds. Influence of iva^shing upon the silver-pur in precipitate. Very large amounts of pancreas, thymus and beef were taken, the obtained purin precipitates dried in vacuo, then decomposed bv HCl and the resultant filtrate tested for the presence OF FOOD STUFFS 31 of albumoses. When the precipitate had been washed with cold water, a distinct biuret reaction was obtained, but if water at 60°C. had been employed, the biuret reaction was absent or of very faint colour. The same result appeared in quantita- tive estimations. If the precipitate from a peptone solution containing a known quantity of guanin was washed with cold water the purin nitrogen was always too high, but after hot washing the figures approximated the nitrogen of the added guanin and were entirely satisfactory : — Pept one Solution. 6% Guanin N added. Guanin N recovered. Hot washing. Cold washing. 20 cc. in 200 cc. ... 0-0244 . .. 0-0228 ... 0-0232 20 cc. in 340 CO. ... 0-0644 . .. 0-0604 ... 0-0663 20 cc. in 640 cc. ... 0-0545 . .. 0-0561 ... 00616 20 cc. in 640 cc. ... 0-0545 . .. 0-0564 ... 0-0605 The examination of the precipitate itself. The washed precipitate was subjected to elementary analysis. The relation of C-N in hypoxanthin and xanthin is as 15 : 14, and in guanin and adenin as 12-14. Estimations of Sheep's Pancras. Found C =19-33% ... Calculated C =15-66% H = 1-56% ... H = 1-30% N =22-67% ... N =18-27% Ag= 49-46% ... Ag= 56-40% With the presence of ammonia and the repeated washing, the possibility exists that a small amount of silver oxide may be formed, but the proportions of C - N in guanin are 12 - 14, and in this case are as 11-91:14. 32 THE PURIN BODIES Witli thymus, C=24-55. N=17-50.-.C-N=19-6:14. Instead of C-N=15:14. Another estimation of thyvius C, 20-15. N, ll-55.-.C-N = 24-4:14. instead of C-N=15:14. In muscle, C=23-10 N=14-23, hence C-N= 22-9: 14, instead of 15:14. The precipitate from pancreas thus appeared to be qiiite pure, but those obtained from thymus and muscle yielded too high a percentage of C, although the amount of N was correct. As in these estimations the nitrogen percentage is all that is necessary, the precipitates are therefore sufficiently pure for practical purposes. In order, however, to remove the surplus carbon, extracts of horseflesh were pre- cipitated by phosphotungstic acid. After filtration, the solution contained a small amount of unprecipit- ated purins. The excess phosphotungstic acid and the II2SO4 were removed by Ba(0H)2, and the barium precipitated by CO2. The solution, after being entirely freed from any remaining traces of barium by the addition of ammonium carbonate, was evaporated and dried at 100°C. until constant, then weighed and decomposed. It yielded the following results : — 0=19-35%. H= 1-40%. N= 18-12%. C:N=la-5:14. OF FOOD STUFFS 33 As tlie calculated proportions of C : IST in xanthin and hypoxanttin are 15 : 14, the precipitate was entirely pure, and thus allowed accurate results to be obtained. Quantitative results. The figures quoted in regard to the washing of the precipitate show that the guanin added to a peptone solution can be almost completely recovered by this process. The following results additionally confirm the conclusion that the method is thoroughly reliable. MtJSCLE Extracts. Found. Purin substance Total Purin. Percentage Purin. added. Calculated. Found. difference. 0-0551 Xajithin 0-0261 0-0812 0-0821 + 1-1% 0-0620 Guanin 0-0777 0-1397 0-1421 + 1-7% 0-0620 Guanin 0-0777 0-1397 0-1510 + 8-1% 0-0713 Guanin 0-0259 0-0972 0-0991 + 1-9% 0-0713 Guanin 0-0259 0-0972 0-0907 -0-2% 0-0629 Hypoxanthin 0-0262 0-0891 0-0928 + 4-1% 0-0310 Hypoxanthin 0-0229 0-0539 0-0526 -2-4% Thymus Extbacts. 0-1568 Guanin 0-0726 0-2294 0-2287 -0-3% 0-4240 Guanin 0-0259 0-4499 0-4496 -0-1% 0-4240 Guanin 0-0518 0.4758 0-4818 + 1-2% Pancreas Extracts. 0-0525 Guanin 0-0363 0-0888 0-0877 -1-3% The modifications which appeared to hasten and facilitate the process are, perhaps, best included in a detailed description of the method. 1. Extraction. The well-hashed meat was boiled for twelve hours in 10 — 20 volumes of 0-5 to 1 per 34 THE PURIN BODIES cent, sulphuric acid. After filtration the residue was boiled several times, filtered and well washed with at first acidulated and later with distilled water. 2. Preparation of the extract for the " direct " preciijitation. The filtrate from 1 was saturated with powdered barium hydrate to strong alkaline reaction. After filtration the barium precipitate was well washed with water at 60°C. and CO2 passed through the filtrate until the fluid became neutral or slightly acid. The carbonate of barium precipitate was then removed, and after thorough washing, acetic acid added to the filtrate, and the latter evaporated to lOOcc. for each lOOgm. of the organic material. It was then made alkaline by the addition of a few cubic centimetres of a mixture containing equal volumes of 33 per cent. NaOH and half- saturated sodium carbonate solution. Any resultant precipitate of BaCOg was then removed and the filtrate first made acid with a few drops of strong HCl and then saturated with ammonia solution. 3. The direct precipitation. To the filtrate from 2, not exceeding in quantity 200cc. for each lOOgm. of meat, 30 — 50cc. of Ludwig's ammoniacal silver nitrate or chloride solution was added. The pre- cipitate obtained was first washed with very weak ammonia, then with hot water until the washings were neutral ; afterwards boiled with a little magnesia (after Arnstein's method) and its nitrogen then estimated by Kjeldahl's process. 4. The indirect or " correctur " precipitation. The filtrate from 3 was acidified with glacial acetic acid, the silver decomposed by H2S, the residue boiled OF FOOD STUFFS 35 several times with weak acid and filtered, the HaS driven off by heat, and the fluid evaporated to lOOcc. for each lOOcc. of meat. Basic lead acetate was then added until the solution was alkaline and precipitation hastened by the addition of a small quantity of talc. The residue was well washed with cold water. After removal of the lead by HaS or H2SO4, the filtrate therefrom was evaporated in acid solution to 20 — 30cc. for each lOOgm. of tissue, and ammonia and ammoniacal silver sohition added. The silver-purin precipitate obtained was treated as in 3, and its nitrogen added to that obtained by the direct precipitate. The amount of the two results gave the total purin. The old lead-acetate method was used as " control " on several occasions, but always showed a slight loss as compared with the direct method. At this point the process adopted by Offer and Rosenqvist may be discussed. They took 25 — 40gms. of hashed flesh, added 250cc. water, and allowed it to stand upon ice for 12 — 20 hours. The proteids were removed by boiling during three periods of 15 minutes each, when albumin tests were said to be entirely negative. It was deemed unnecessary to acidulate, as the flesh itself was slightly acid. After the filtrate had been made up to 500cc., lOOcc. (5 — 8gms.) were taken for the estimation of the santhin bodies. The method was simple and expeditious, but could scarcely yield more than approximate results. The ice extracts would certainly contain the free " purins," but the bound " purins,'' which consist of 15 to 25 per cent, of the total amount, would be unextracted. 36 THE PURIN BODIES Furtlier, in regard to the removal of the albu- minous bodies, if the reaction of the filtrate was sufficiently acid to produce com^plete coagulation, it would probably, during the 45 minutes at 100°C., cause the formation of small quantities of albumin- ates or albumoses. On the other hand, Fiirth has shown that plasma obtained from the muscles of fishes contains a proteid, myoproteid, which is not coagulated by heat, and is only precipitated by strong solutions of acetic acid; this by Offer and Rosenqvist's method would remain in solution, swell the total extractive N and prevent the complete precipitation of the purins. There is no mention of filtration after the addition of NH^OH, so that while the purin-N would be too small from the imperfect extraction, the presence of other nitrogenous bodies would incorrectly increase its amount. I used Rosenqvist's method in an estimation of chicken flesh, and obtained 0'0262 purin-N. This compared favourably with Offer's results 0300 purin-N^. The residue from the cold extract was then boiled with 0'5 per cent. H2SO4 for 12 hours, and precipitated with Ba(0H)2, the Ba(0H)2 removed by H2SO4, and the filtrate precipitated with AgNOg and NH4OH. The pre- cipitate yielded 00144 purin-N. The filtrate from the first silver precipitate was acidified, the silver removed by H2S, the filtrate heated until the H2S was dispelled and then precipitated with a solution of subacetate of lead. After removal of the lead, AgNOg and NH4OH were added, and the precipitate obtained yielded 0'0087 purin-N. OF FOOD STUFFS 37 Thus the original result of 0-0262 N. by Ofier's method plus 0-0087 N. from „ filtrate plus 0-0144 N. „ „ residue gives a total of ... 0-0493 purin N. Estimationsi by the method as described above gave 0-0501 purin N. 0-0532 „ so that there was a loss of 0-023 N. or 0-055 xanthin bodies by Offer and Eosenqvist's method (0-0493—0-0262). For purposes of comparison, the total nitrogen and the total " extractive " nitrogen were also estimated; 1 — 2gm. were taken for the former, and 25 — 50gms. for the latter. A cold extract was made, and the N. taken after the removal of the albumins and albunainates. The result was naturally only approxi- mate, as the bound nucleins were unextracted, and a small amount of albumose may have been present. The precise total quantity was not, however, per- tinent to the enquiry. In relation to the effect of food purins upon the urinary excretion, it was necessary to examine the total urinary purins. For their amount, Arnstein's modification of Camerer's method was employed. Uric acid was estimated by Hopkin's ammonium chloride process, and the xantliins calculated by difference. In the former case the crystals were weighed, and control studies were made by the Ludwig-Salkowski process. Phosphoric acid was titrated against uranium nitrate and expressed in terms of PaOg. For the extraction and estimation of purins in 38 THE PURIN BODIES vegetables and beverages, 250gms. — 2 kilos were boiled for twelve bours in 0'5 per cent. H3SO4 solu- tion. Tbis was tben neutralised, and tbe filtrate tberefrom was acidified witb acetic acid and again filtered. Tbe extract was next boiled for 5 — 10 minutes and any resultant precipitate removed. Excess of copper sulpbate and sodium bisulpbite were tben added, and tbe fluid again boiled. After standing for 2 — 10 bours tbe precipitate was filtered off, and tbe residue well wasbed witb water at 60°C. I found it of advantage to allow tbe precipitate to dry until cracks appeared, and tben grind it in a mortar until it was entirely pulverised. Tbii facilitated tbe next step of suspension in boiling water, and tbe subsequent precipitation of tbe Cu as copper sulpbide by H2S or KjS. Tbis precipitate was wasbed witb H2S water, tbe filtrate freed from HoS by beat, and evaporated to about SOOcc. After tbe addition of NaOH and NaaCOg, subsequent filtration and acidification, strong ammonia solution was added. Wben tbe fluid gave no proteid reactions silver nitrate was used, and tbe purin-N. found by Kjeldabl's process as usual. Tbis metbod gives satisfactory results, except wben large quantities of proteid matter are present, as in tbe legumes. Witb tbese it appeared safer to take tbe final filtrate and treat it in tbe same manner as tbat from tbe meat extracts, adding tbe two results togetber. As a rule tbe copper precipitation was repeated twice or tbrice, until tbe silver purin precipitate was colourless. OF FOOD STUFFS 39 CHAPTEE III. Estimations. The Quantities of PtmiNS in Meat Foods. In raamnialiail imiscles a considerable quantity of fat is found, and by its presence in streaks within tht lean portions of meat, tbe quality of a specific cut or joint is more or less judged. The object of the breeder is, therefore, to produce in his cattle the appearances which the public prefer during the several seasons, and he obtains these by variations in the feed and environment. As the percentage of fat is thus changed according to the time of the year, and may vary between 1"5 — ^29 per cent., the quantities of the other constituents will be propor- tionately altered. Still, analytical results show certain limits of variation in regard to the different species, and so permit of their application to scientific and clinical purposes. Additionally, the many parts of the same animal vary both in regard to their proteid and extractive percentages, and this fact should be also remembered. With fish and fowl flesh, these matters are of less moment. The following table is constructed from my own estimations, and is intended to show the amounts of purin bodies contained in the more common of 40 THE PURIN BODIES the meats found in tlie English dietary. The extracts were made from flesh purchased in the ordinary way from a butcher, and with the fat and other contents intact, just as they are used in the household. This was thought preferable to the separate analysis of lean and fat portions, which would have made the results inapplicable to the necessities of daily practice. Table IV. Fish: Percentage of Purin Nitrogen. Average X of Nitrogen. Calculated as Purin bodies. Undried Purins. As grains As grains per kilo, per lb. Cod 0-0219 0-0247 0-0233 0-0582 0-582 4-074 Plaice 0-0334 0-0302 0-0318 0-0795 0-795 5-565 Halibut 0-0405 0-0412 0-0408 0-1020 1-020 7-140 Salmon 0-0482 0-0450 0-0466 0-1165 1-165 8-155 MEATS . Tripe 0-0235 0-0224 0-0229 0-0572 0-572 4-007 Mutton — Australian 0-0365 0-0386 0-0965 0-965 6-755 English . . . Veal- 0-0411 Loin 0-0454 0-0481 0-0465 0-1162 1-162 8-137 Neck 0-0300 Pork- Loin 0-0485 0-0485 0-1212 1-212 8-487 Neck 0-0257 0-0198 0-0227 0-0567 0-567 3-969 OF FO OD STXJ FFS 41 Ham 0-0505 0-0462 0-1155 1-155 8-085 *(Fat) ... 0-0419 Beef- Ribs 0-0455 0-0455 0-1137 1-137 7-959 Sirloin . . . 0-0506 0-0538 0-0522 0-1305 1-305 9-135 Steak . . . 0-0826 0-0826 0-2065 2-066 14-455 Liver 0-1125 0-1078 0-1101 0-2752 2-752 19-264 Sweetbread — Thymus ... 0-4025 0-4025 1-0063 10-063 70-431 Chicken 0.0495 0-0546 0-0518 0-1295 1-295 9065 0-0512 Turkey 0-0504 0-0504 0-1260 1-260 8-820 Rabbit 00305 0-0456 0-0380 0-0970 0-970 6-314 These figures call for little discussion at the m.onient. Certain meats appear richer in purin than others, but with the exception of liver and sweet- bread, and when the amount of each sort necessary to provide the requisite amount of proteid or the feeling of satisfaction, is calculated, there is not much, difference between the several species. More fish is generally eaten than beefsteak, if the meal consists solely of one or the other; tripe is usually a supper luxury, and sweetbread is, as a rule, taken sparsely. But the form in which the purins occur is interesting in regard to their metabolism, and further investigations were undertaken in order to * Considerable difficulties were experienced with this owing to the use of curing substances, principally potassium nitrate. 42 THE PURIN BODIES determine the relations of tlie free and bound purins in meat foods. For this purpose an extract was made with. 0'5 per cent. H2SO4 solution, and kept for 24 hours upon ice, as Meischer has shown that there is no cleavage of nucleins when the tempera- ture does not exceed 2 — 3°C. The filtrate from this extract contained the free purins and was treated as usual. The residue was boiled for 12 hours in 05 per cent. II2SO4, and then precipitated by a mix- ture of basic and lead acetate, the lead removed by H2SO4 and the purins obtained as silver compounds. It is possible that a small quantity of the bound purin was present in the first filtrate, but it may be safely neglected. Appended to the table stating the results obtained are the figures of Burian and Schur and of Katz showing the relation of the phosphorus and sulphur to the bound purin. Table Y. The " Free " and " Bound " Purins of Meats. ■' Free" purin. "Bound" purin. VS>^. Sulphur. Nitrogen. Nitrogen. Cod 0-0299 . . 0-0106 . Tripe 0-0143 . . 0-0092 . Chicken ... 0-0348 . . 0-0147 . Ham 0-0398 .. . 0-0064 . . 4-8702 . . 2-0430 Oxflesh ... 0-0460 .. . 0-0070 . . 3-8944 . . 1-8677 Veal 0-0430 .. . 0-0100 , . 5-0291 . , 2-2586 Liver 0-0330 . . 0-0790 . Sweetbread 0-0420 . . 0-3.510 . As possessing some interest in relation to the percentage of purins already cited, and as a con- OF FOOD STUFFS 43 tribution to existent analyses, my estimations of tlie total nitrogen, and the total extractive nitrogen of the meats examined are given in the following table : — Table VI. Total Total Extrac- Total Total Extrac K. % tive N. % N.Z tiveN.% Cod Plaice 4-445 4-645 4-922 3-356 0-2659 0-1949 0-5600 Pork ... 2-576 2-324 2-216 2-284 0-2097 0-2151 0-2276 3-040 Ham . . . 4-200 Halibut ... 3-370 3-360 0-3570 d^yjW 5-840 5-860 0-4710 Beefsteak 4-900 0-4800 Tripe ... 2-800 0-0980 4-390 2-600 0-1036 Chicken... 3-560 Mutton ... 3-102 0-3908 Babbit ... 3-245 0-2450 Veal 3-136 0-4690 3-382 2-856 0-3250 Liver . . . 3-122 2-904 0-2850 The amount of total nitrogen multiplied by the factor 6'25 will give the proteid percentage. The extractive nitrogen consists of creatin, creatinin, hypoxanthin, xanthin, in some instances methyl- xanthins, and perhaps urea, carnin, and inosinic acid. Considerable emphasis has been laid upon the alterations produced in the amount of extractives by cooking, and one infers from the remarks of Senator that the various kinds of meat may yield altered percentages of residual purins when prepared and ready for eating. Apart, however, from the fact that both roasting and boiling render meat more 44 THE PURIN BODIES sapient by coating its surface witL. extractive matter, supplying a solution of purins, etc., known as gravy, and lessening its digestibility by tbe coagulation of proteids, tbere is only a very sligbt decrease in the amount of total purins. If it were customary to eat meat food, minus tbe gravy produced during tbe process of preparation, tbe matter migbt be of moment, but as not only tbe gravy obtained from tbe meat, but also an additional purin contribution from some fasbionable meat ex- tract is served, it is probable tbat more purin is taken witb tbe cooked meat tban exists in tbe fresbly killed muscles. Hence, although the percentages of purin nitrogen are expressed in terms of tbe raw undried substances, they may be satisfactorily applied to the several forms in which animal food is usually partaken. The Pueins of Vegetable Foods. It is iisually stated tbat while vegetables contain much water, indigestible cellulose and varying amounts of proteids, their extractive matter is very small. Consequently only a few stray estimations are recorded of the purins existent in vegetable foods. Jerome noticed an increased uric acid excre- tion after the ingestion of large quantities of large quantities of asparagus, and was led to investi- gate its nuclein percentage, and found 00854gm. in 500gms. of asparagus (00171 per cent.). TheKrtiger- Wulff method was employed. Burian and Schur with the object of finding a purin-free food, analysed OF FOOD STUFFS 45 bread, potatoes, rice and cabbage, but observed traces of purin bodies. The following determina- tions will not only confirm the general impressions but furnish, precise data in regard to the nuclein nitrogen of vegetable life. The percentages are certainly small, but if vegetable food is solely used, larger quantities are required than when meat is taken. As a rule, plants have no excreta except gaseous bodies, so that katabolic resultants of a solid nature are retained within the organism; these excretory products are, however, always removed to such localities as ensure their withdrawal from the spheres of vital activity, and are met with in not inconsiderable quantities in the bark of trees, dead leaves, cell walls, etc. Table VII. includes some of the ordinary articles of vegetable dietaries, and demonstrates the need for recognition of their purin-holding capacity. 46 THE PURIN BODIES Table VII. Cereals ; Bread — white Oatmeal Quantity Purin Calculated as used for Nitrogen. Purin bodies. Grams Estimations. % % per kilo. Rice Pulses : Peameal 500 grams no trace — 250 „ 00212 0-0530 0-0210 500 „ no trace — 0-530 250 „ Beans (Haricot). 500 Lentils Lentils (malted). Roots and Tubbks : Potatoes 500 „ 500 ,, Ikilo 0-0156 0-0278^ 0-0247 0-0250 0-0252 0-0250 0-0250 0-0252 0-0150 0-0156 00390 0-390 Grains per lb. 3-4563 2-5413 00637 0-6375 4-1661 0-0637 0-0375 Onions 0-6375 0-3755 0-0200 0-090 4-1661 2-3340 0-1400 0-0630 Tapioca Green- Vegetables Cabbage Lettuce Cauliflo-wer Asparagus (cooked) 0-0008 0-0020 00006 250 grams 0-0031 0-0090 00040 250 ,, no trace — large head , , — 700 grams 0-0086 0-0215 02150 1-5050 OF FOOD STUFFS 47 The Pueixs Contained in Beveeages. So many analyses of tea, coffee, and cocoa exist, that it is imnecessary to add to them. From the following table it will be seen that although purin bodies were not found to be present in wines, they existed in fairly large amounts in other fermented liquors. Probably their presence is due to peculiarities in the yeasting process. The work of A'ictor Lehman is interesting in this regard. He took 300 gms. of yeast and allowed it to stand for 24 hours at ordinary-room temperature. The filtered flxiid yielded traces of hypoxanthin and 0'0179 gm. guanin. Further estimations of the yeast itself at body temperature demonstrated its tendency to the formation of hypoxanthins and guanins. The significance of these facts will be discussed under another heading. It sufiices now to remark that a large percentage of the existent records of uric acid excretion are from patients or workers whose dietary included beer and porter. Table VIII. contains the amount of purins found in the beverages examined. 48 THE PURIN BODIES Table YIII. Beers : Lager B eer Quantity used for estimation. 1 litre Purin 0-0050 Purin 0-0125 Purin grams grains Iter litre. per pint. 0-1250 1-0955 )) 0-0053 Lager dr nk 0-0020 0-0021 0-0050 0-0500 0-1533 Pale Ale 0-0059 0-0056 0-0145 0-1450 1-2708 Porter 0-0060 0-0062 0-0155 0-1550 1-3578 Wines : Claret J litre no trace — — — Volnay Sherry Port... )5 ;) — — — (Commendador) Tea, &c. : Methyl-purins Per tea -cup. Ceylon 0-0164 0-0587 0-0805 1-210 Indian 0-0147 0-0500 0-0700 1-050 China 0-0107 0-0365 0-0460 0-750 Coffee — - 0-0294 0-1000 0-1100 1-700 Milk, butter, eggs, and cheese slioiild be placed under tlie heading of animal foods, but they are best estimated by the method Trhich Tvas employed for vegetables, and so m^ay be considered as a separate class. Eggs contain no free purin or purin- yielding substance. Butter and cheese are deriva- tives from milk, and so may hold traces of nuclein bodies. The percentages of casein and -(vater vary in different samples of butter, and the same remark OP FOOD STUFFS 49 may be applied to cheese. When the curd is pre sent, any xanthiu present in the milk will pass into the slightly acid whey, just as the process of churn- ing or separation assists their removal from the butter, and hence only minute traces can remain in these two substances. In milk, Petren was unable to find any purin bodies, but Burian and Schur by complete removal of all the albuminous bodies found 00014gm. purin-N. per litre. An estimation of my own yielded 0'0020gm. N. per litre. The quantities are very small, but are probably correct, as Barthel, of Stockholm (private communication), by use of the centrifuge has enumerated at least 100,000,000 leucocytes per kilo of ordinary cow's milk. These four articles of diet form together our most valuable m eans of withholding purin substances from the body, and yet allow the provision of a diet at once digestible, easily absorbed and capable of m^aintaining nitrogenous equilibrium. 50 THE PURIN BODIES CHAPTER ly. The Actiox of Food Pueixs. When- Liebeg first introchiced his " extract of meat," many investigations were undertaken to demonstrate the effect of the extractives upon the body, but since then they have received little attention. Current handbooks upon dietetics regard them as somewhat necessary evils, and almost negative in character. They are considered to yield no potential energy, to exert no influence upon the circulatory or nervous systems, although they maj' remove the feeling of fatigue and slightly aid digestion. Their excretion throws extra work upon the metabolic and elimina- tive organs, and hence their passage through the organism is accompanied by a loss of energy. Rarely is any reference made to their cumulative after effects, which are possibly of deep import. Alimentary system. The food purins are power- ful sapients, and both directly and indirectly increase the salivary flow. The secretion induced is, however, more watery than digestive. The gastric juice, according to Pawlow is similarly affected, but Potapow-Procaitis has recently observed that although meat extractives increase the total quantity, they invoke little secretion of pepsin, and only affect the production of hydrochloric acid. He fed a dog (which had a Pawlow's fistula) upon milk. OF FOOD STUFFS 51 boiled egg albumin, and meat that had been saturated with water in order to remove all soluble substances. Though Pawlow had determined that the amou^nt of gastric secretion was proportional to the digestive intensity required by the ingesta, in Potapow's experiment little peptic secretion was induced. When, however, meat-extract or dextrin was added to the other food, a copious flow of pepsin immediately followed. Mark Schnorf, however, finds that puic dextrin does not cause peptic secre- tion, and ascribes the action of the ordinary dextrin to certain accompanying ejitraetirc bodies. Lehman had severe diarrhoeic attacks after taking large quantities of Liebig's extract, but these were probably due to the mineral constituents. Pure adenin causes, in the dog, intense inflammation of the mucou^s membranes of the stomach and intes- tines. Uric acid produces irritation of the gastric and intestinal mucosa and in some cases slight diarrhcea. llypoxanthin and xanthin are readily dissolved by the acid secretions of the stomach and thus are quickly absorbed. Xanthin, however, is less soluble than hypoxanthin. Some as yet unpublished experiments appear to indicate that in man guanin is not easily absorbed. The nucleoproteids may be absorbed unaltered by the intestinal mucous mem- brane or be split up by the pancreatic juices and their phosphorus excreted in the faeces. Mochizucki has shown that rectal enemata con- taining emulsions of thymus gland lead to increased uric acid excretion in man. Mendel, Underbill, and 52 THE PURIN BODIES White liave obtained allantoin excretion in animals after a similar procedure, but tbey did not obtain any increased uric acid output after the rectal injection of nucleic acid. Kuelnau injected thymus emulsions and thymus nuclein into the peritoneal cavity of a dog and found an increased output of uric acid. Mendel, TJnderhill and White have recently observed an excess of allantoin after the intra-peritoueal injection of nucleic acid in dogs. After the injections there -svas vomiting and a slight rise in temperature. Caffeine and theobromine do not exert an}' direct action upon the digestive functions, but after large doses, through overstimulation of the intestinal muscles, cramp and vasomotor disturbances may occur, followed by loss of the intestinal secretions. Circulatory system. On the vascular system, the methyl-purins exert the more pronounced action. The earlier workers in this field concluded that these bodies directly' stimulate the heart, augment its force, lessen the pulse-rate, and increase the blood- pressure. Parisot ascribed the whole action to a vasotonic origin, and Yinci obtained, after injections into normal animals, a constant rise of peripheral vascular pressure. Cushnj- and Yan Naten now consider, however, that the most characteristic features of the action of caffeine are the acceleration of the rhythm, and a decreased strength of contrac- tion in the auricle and later in the ventricle, accom- panied or followed by a lessened degree of dilatation in diastole. In their experiments, after 0'2 — Igm. a dog's heart became irregular, and the auricles and OF FOOD STUFFS 53 ventricles beat arhythmically. Larger doses in- creased the irregularity and caused fibrillary con- tractions. The acceleration results from the stimu- lation of the so-called escitomotor apparatus of the heart. The lessened contraction may be due in part to the acceleration, and thus be considered as a secondary effect of the increased irritability of the vasomotor area, but it may be also caused by the direst action of caffeine upon the muscle of the auricles and ventricles. The whole action of caffeine upon the mammalian heart thus appears to consist in a descending stimulation which begins in the excitomotor area at the junction of the auricles and great veins, extends into the auricles and finally intc the ventricles. The effects can be therefore explained by direct action on the cardiac muscle itself, without the necessity of appealing to any nervous apparatus. Santesson, working with a cannula in the peri- cardium, finds that administration of caffeine causes increase of pressure and of cardiac rhythm. From the comparative effect of digitalin and cardiac poisons he concludes that as caffeine only increases the systolic part of the contractions, it exerts a direct and tonic action on the cardiac muscle. Mitchell Bruce regards tea, coffee and cocoa as extrinsic cardiac poisons. As to the purins proper, Gautier states that xanthin excites cardiac muscle, but Baldi found it absolutely inactive on the frog's heart, although allantoin appeared to be slightly excitatory. Adenin, however, when subcutaneously injected. 54 THE PUEIN BODIES strengthens the beat of the dog's heart. Hedbom observed an increased tonus and rhythm of tlie isolated heart, following the application of a watery splenic extract. Lehman, after drinking varying amounts of beef extract, found no alteration in the rapidity or force of the pulse. Bunge obtained similar results, but Kenimerich observed a slig'ht rise in pulse frequency. Hutchison ascribes any cardiac effects to the hot water in which the meat extracts are usually taken, or to the effects of con- stant sipping. Blood. Milroy and Malcolm observed in young rabbits, killed 2 — 10 days after the injection of 0'2 — 0'5gm. of nucleic acid, an accumrilation of white cells in the pulmonary capillaries, an increase in the finely granular myelocytes in the marrow and a diminution in the coarsely granular oxyphile cells. The number of granules in the cells was also lessened and the usual oxyphile granules appeared to more readily take the basophile stains. Adenin, guanin and cytosin obtained from thymus nuclein produced similar results. In guinea pigs, however, the effects were neither so constant nor noticeable. L. Hue, in 1898 (proceedings of the Physiological Society), observed that when the Drosera was fed upon nucleic acid although the basophile chromatin seg- ments were unaltered, an extremely copious secretion appeared, accompanied by rapid bending of the tentacles. Except very slight protoplasmic vacuola- tion, nuclein itself, however, produced no cytological changes. Bang, after intravenous injection of guanylic acid OF FOOD STUFFS 55 (from pancreas) into dogs, observed immediate excita- tion followed by temporary narcosis. The blood pressure fell, quickly and the pulse became smaller. After varying periods the heart beat gradually became more forcible and the blood pressure normal. The rate of coagulation was considerably lengthened. The urine was distinctly alkaline and contained albumin. Mendel, TTnderhill and "White obtained similar results after nucleic acid prepared from the wheat embryo. They also observed an increase in the flow of lymph and in the percentage of its total solids after intravenous injections of vegetable nucleic acid. The recent work upon the caffeine group is interesting in relation to the action of the santhin bodies. If the former exert a tonic action upon the cardiac muscle cells, it is not unlikely that when they become demethylated in the body, they may equally as the other purins act as slight irritants to the tissues. Additionally, the purin bodies are constantly taken with the food, they throw con- siderable work upon the metabolic and excretory functions and if at any time these are sub-normal, the unexcreted purins may exert cumulative effects upon the circulatory organs and the blood. Respifatofy System. In 1859, Edward Smith and Hoppe-Seyler found that tea and coffee excited the respiratory functions, and caused an increased out- put of CO2, the effect lasting for over an hour. In both eases, however, the experiments were made with apparatus now considered unreliable. Smith wore a mask which covered the face, and which was con- 56 THE PUEIN BODIES nected by rvibber tubes with the absorptive media. The method was trying and tiring, and as Hoppe- Seyler has since pointed out, gave abnormal results. No evidence exists as to the action of the other purins either upon the CO2 output or upon the respiratory mechanism. Leven in 1868, Giraud in 1881, and Parisot in 1890 observed that the admini- stration of caffeine to animals caused acceleration of the respiratory movements, but after toxic doses the respiration ceased before the heart was arrested. In tea and coffee, however, there are other bodies which cause increased respiratory exchanges, for Binz and Archangelsky find that a distillate of tea and coffee, free from caffeine and thein, augments both the output of CO2 and the number of respira- tions. Heerlein had earlier pointed out that the coffee distillate also affected the nervous system, but Lehman and Wilhelm, in 1898, considered that the distillates were inert. Still, as all aromatic sub- stances are tissue irritants, and increase reflex excitability, it is probable that the contents of the distillate are responsible for the observed effects. The increase in the elimination of CO2 found in the earlier experiments may thus, in some degree, be due to constituents of tea and coffee other than caffeine and theobromine, as well as to the methods of experiment and analysis which present the objec- tions previoiisly noted. Gcnito-iirinary system. That the methyl-xanthins are useful diuretics is a fact long since appreciated. The recent works of Anthen and Gottleib and Magnus shoV that the methyl-purins act as direct OF FOOD STUFFS 57 excitants of the renal parenchyma, and lead to an increased excretion of the nitrogenous elements, especially of urea and uric acid. Ach finds that in rabbits they are less effective. Uric acid appears to be without effect on the renal cells, although it is quite possible it may possess some lymphagogic properties. After the injection into rabbits of small doses of hypoxanthin, Gaucher observed inflammatory changes in the kidney parenchyma, and these were confirmed later by Kolisch. Croftan produced under similar conditions interstitial as well as parenchymatous nephritis, albuminviria, nephritic endarteritis, and small-celled infiltration of the intima and adventitia. These changes were accom- panied by an increased blood pressure and cardiac hypertrophy. In some of the animals distinct emaciation occurred. Parallel investigations with uric acid gave negative results. Upon these obser- vations is reared the imposing theory of the alloxur- base causation of the chronic forms of nephritis, which now, however, is somewhat discredited, since it has been impossible to prove the existence of large quantities of the purin bodies in the human blood stream. The aminopurins, when obtained from thymus or pancreas are excreted in unaltered condition, but when administered in a pure form, adenin causes in the dog an intense inflammation of the tubular cells, and uratic deposits in the lumen and interstices of the renal epithelium. Interesting in this rela- tion is the work of Steudel, who considers that 58 THE PURIN BODIES thymin tlirough its close connection with the hypo- thetical " nracil " may be akin to pyrimidin deriva- tives. In the hope of obtaining purin bodies by systemic synthesis, he fed a dog with methyluracil, nitro-uracil, dioxypyrimidin, etc., but the urinary purins were not increased, and no toxic symptoms were observed. When, however, he added an amido- group, as di- or tri- amino-oxy-pyrimidin, O'l — 0'2gms. were lethal to rats, and in the kidney tubules there was deposited an almost insoluble salt of the unchanged base. Xnrous system. In small doses caffeine and theo- bromine are cerebral excitants, and after toxic quantities the medullary centres are dii-ectly affected, the motor functions of the cord accelerated and the peripheral nerves, particularly the pneumo- gastric, paralysed. Baldi supposes that their action is due to the liberation of a methyl group. This group has no precise stimulative effect, the excita- tion being dependent upon the way in which protoplasmic activity causes its liberation, and the particular portion of the purin nucleus to which it is attached. Xanthin and hypoxanthin do not increase the excitability of the spinal cord, but Grautier obtained excitation of reflexes and tetanus after the injection of hypoxanthin in guinea-figs. According to Salomon and Krtiger the alloxur bodies cause migraine, and after large doses of uric acid, taken for experimental purposes, I have myself had headache lasting for several hours. Muscular system. The purin nucleus itself exerts a specific action upon muscular tissue, and its effect OF FOOD STUFFS 59 is quite independent of any attached groups. Kobert and Rossbach observed that the application of hypoxanthin to frog's muscles after severe muscular efforts, caused renewed activity, and inferred that it removed the sense of fatigue and stimulated muscular tissue. Filehne noticed muscle rigidity and tetanus in frogs after hypoxanthin, and rigidity followed by cardiac arrest after santhin. Guanin and uric acid up to lOOmgm. were inert. Mitscherlich et Bennett and Filehne, in 1887, observed similar results with di-oxy-purins ; and Paschkis states that the toxicity becomes more intense from the hypo- to the methyl-xanthins. Johannsen, after caffeine injection in frogs, obtained muscular rigidity and loss of excitability, and by analogy between blood and muscle plasma coagulation, Klempner thought that caffeine thus evoked the development of a coagulative ferment. Although Eossbach and Hartenack were unable to confirm these results, they have since been substantiated. Leblond observed that in frogs, caffeine produced a period of transitory rigidity followed by tonic and tetanic convulsions and diminished excitability, and thought that the action was first upon nervous and later upon muscular tissue. Lusini states that the minimum toxic and fatal doses decrease from the mono- to the tri-methyl xanthins, and that the resistance of the muscle against fatigue increases in an inverse direction, and Fere concludes that although muscular power is for a time increased, yet caffeine causes an earlier appearance of fatigue than that which normally occurs. Baldi points out 60 THE PURIN BODIES that wliile the methyl group is responsible for the excitation, it is the xanthin or purin nucleus alone ■which produces the rigidity and hyper-excitability. Finally, Schniiedeberg has published the results of an interesting investigation upon the role played by the oxy and alkyl attachment to the purin nucleus, and shows that whilst these groups may alter the intensity of action, the purin nucleus still exerts its own specific action upon muscular tissue. In experiments with substances akin to the purin bodies two conditions must, however, be always remembered ; (1) that the relative actions of the several purins may be due to their varying solubilities, which in the one case allows free circula- tion in the lymph spaces, and in another permits only partial absorption by the individual cells ; and (2) that they may form weak salts with some of the lymph constituents, and so obtain augmented or diminished powers. Metabolism. The purin bodies do not appear to exert any direct influence on either carbohydrate or nitrogenous metabolism. Acting through the nervour system, caffeine is said to raise the tonus of the tissues, and so permit the organism to utilise its reserves. Indirectly, however, they invoke an output of metabolic energy to ensure their early removal from the body. They are not used for the production of cell nuclein. In regard to the " forced feeding " treatment of tuberculosis and the small percentage of infective disorders amongst gouty patients, it would be of value to know if an excess of purin bodiec in the OF FOOD STUFFS 61 bloodstream increases or diminishes tlie immunity of the individual, or if there is any alteration in bacterial cultures, when purins form one of the constituents of the media. Bendix has lately shown that the presence of uric acid neither retards nor diminishes the growth of certain micro-organisms, and I have been able to confirm these results, especi- ally as regards several varieties of micrococci. When uric acid, hypoxanthin and guanin were severally added to the nutrient media, the resultant growth in no way differed from that of the control tubes. 62 THE PURIN BODIES C'HAPTEE Y. The Comparative Effect of Prnix Bodies upon THE PeODUC'TIOX OF C'( )„. As previoiisly cited, earlier investigators observed an increased production of CUo after tlie ingestion of tea and coffee. These increases were obtained, how- ever, by the use of unsuitable apparatus and by unsatisfactory methods of analysis. It would thus be of interest to compare the results of modern experimental methods with those already recorded, and preferably to employ pure caffeine instead of an infusion of coffee. With the object of making such comparison, and also to ascertain the action of the other purins upon the carbohydrate metabolism, the following studies were devised. The subject of experiment rose about 7-30 a.m., walked an Eiiglish mile, and still fasting, entered the Sonden-Tigerstedt respiration chamber about 8-30 a.m., and lay absolutely still upon a mattress for 30 minutes, covered only with a light felt rug. One sample of air was taken five minutes after entry, and another thirty-five minutes later. The temperature and pulse-rate were observed at the commencement and at the close of each experiment. The analyses were made by a Sonden-Peterson's apparatus. OF FOOD STUFFS 63 W. H., OF Manchester. Nov. 18, 1901, 8-0 a.m., |gm. Benz. Natr. CO^ Caffeinicus. excretion. 8—30 a.m., ^ gm. „ 8-35 a.m., Temp. 36-5° C, pulse 80. 9-5 a.m., Temp. 37-8° C, pulse 78. 14' 6 gm.s. Sensations of warmtli in abdomen and over tlie whole surface of the body. Intense headache, which lasted the whole day. Muscular fibrillation in muscles of the back and thigh. Nov. 19, 8-35 a.m., Temp. 36-5° C, pulse 80. 9-5 a.m.. Temp. 36-5° C, pulse 78. ll'Sgms. Nov. 20, 7-30 a.m., 0-25 gm. Hypoxanthin in slightly alkaline solution. 8—15 a.m., 0'25 gm. Hypoxanthin in slightly alkaline solution. 8-20 a.m.. Temp., 36-5° C, pulse 76. 8-50 a.m., Temp. 36-5° C, pulse 76. ll'l gms. Slight fulness in head, and a feeling of stiffness over the whole body. Nov. 26, 7—45 a.m., 0'25 gm. uric acid partially dissolved in alkaline solution. 8—20 a.m., 0'25 gm. uric acid partially dissolved in alkaline solution. 8-30 a.m.. Temp. 37° C, pulse 84. 9-0 a.m.. Temp. 36-5° C, pulse 84. 14-3 gms. There was distinct headache and confused ideas. Sensation of warmth in the stomach. E 6i THE PURIN BODIES Nov. 28, 7-45 a.m., 0'25 gm. uric acid partially dissolved in alkaline solution. 8-30 a.m., 0'2i) gm. uric acid partially dissolved in alkaline solution. 8-33 a.m.. Temp. 37° C, pulse 84. 9-3 a.m.. Temp. 36-.5' C, pulse 84. 11-6 gms. Slight headache, sensory disturbances in abdomen. Nov. 29, 7-45 a.m., 0'5 gm. Benz. Natr. Caffeinicus. 8—15 a.m., 0'5 gm. Benz. Natr. Caffeinicus. 8-26 a.m., Temp. 36-6° C, pulse 84. 8-56 a.m.. Temp. 36-5° C, pulse 72. 14-3 gms. Fulness in head ; loss of muscular sense ; confused ideas. Nov. 30, 7-45 a.m., 0'5 gm. uric acid, entirely dissolved in sodium carbonate solution. 8-15 a.m., 0"5 gm. uric acid, entirely dissolved in sodium carbonate solution. 8-35 a.m.. Temp. 36-8° C, pulse 90. 9-5 a.m., Temp. 36-5° G., pulse 76. 11-0 gms. Dr. EniHEERE A. C, of Finland. Normal rest value 9' 8 10-3 gms. 10-3 gms. CO2 excretion. 10-0 Nov. 21, 7-30 a.m., 0'5 gm. Benz. Natr. Caffeinicus. 8-0 a.m., 0'5 gm. Benz. Natr. Caffeinicus. 8-5 a.m.. Temp. 36-1° C, pulse 60. 8-35 a.m., Temp. 36-1° C, pulse 60 (fuller) 10-7 gms. No headache ; slight warmth over whole skin area ; no fibrillations. OF FOOD STUFFS G5 Nov. 25, 7-30 a.m., 1 grm. Benz. Natr. Caffeinicus. 8-0 a.m., 1 grm. Benz. Natr. Caffeinicus. 8-12 a.m., Temp. 36-2° C, pulse 62. 8-42 a.m., Temp. 36-2° C, pulse 62. 12'3 gms. Headache; abdominal warmth, followed by diarrhoea in the later part of the day. Professor Saxtesson, of Stockholm. Dec. 5, 8-25 a.m., Temp. 36-8° C, pulse 56. 8-55 a.m., Temp. 36'8° C, pulse 56. 10'5 gms. Dec. 7, 7—55 a.m., ^ gm. B,enz. Natr. Caffeinicus. 8-25 a.m., J gm. Benz. Natr. Caffeinicus. 8-35 a.m.. Temp. 37-0° C, pulse 56. 9-5 a.m.. Temp. 37-1° C, pulse 57. 12-5 gms. Audition slightly augmented, also sensation of body warmth. No headache. The results show that my early morning CO.j excretion is about 11 grammes per half-hour. The values of Professor S. and Dr. C. are slightly lower, as also their pulse-rate and temperature. "With Professor S. and myself, caffeine caused an increased production of CO2 in average doses, but an almost toxic dose was required before any effect was manifest upon Dr. C. It would appear, therefore, that although caffeine may incite increased combus- tion, it acts variously upon different individuals. The results recorded do not indicate whether the excitation is directly upon the metabolic organs, or indirectly through the neivous system. At all events, caffeine increases the elimination of CO2 in many cases — a fact of interest in the consideration 66 THE PUEIN BODIES of the treatments available for tlie alterations of cell-activities during stasis. Hypoxanthin, the monoxypurin, yielded negative results, and uric acid, the triosypurin, may probably be placed in the same category. The chemical constitution of these bodies and their behaviour during metabolism, pointed to the probability of their inactivity, but the observations have yielded results which indicate the limited role of the purin-nucleus, and allow us to ascribe the effects of caffeine upon respiration to the action of its methyl-groups. That the latter mainly excite nervous tissues is certain, but that they may also directly affect cellular processes is not disproved and not improbable. In these experiments, however, the action of uric acid was somewhat irregular. On the first occasion, when the uric acid was only partially dissolved, there was a sensation of warmth in the alimentary canal, which, apart from the intense headache, would be sufficient to account for the rise obtained. There was no headache on the second day, but the stomach sensations were present ; for the third experiment the uric acid was com- pletely dissolved in 340cc. of Naa CO3 solution, and neither headache nor other symptoms interfered with quiet respiration and general comfort. Possibly my body became rapidly tolerant of the repeated doses of uric acid. That the substances taken were duly absorbed appears from the following records : — OF FOOD STUFFS 67 Table X. Nov. 21, 7-30 a.m. Urine passed : „ 21, 8-15 a.m. 0'5 gm. Hypoxanthin (020 purin N.) Total purin Urine. Total N. Nitrogen. 10 a.m.— 12 noon 415 cc... 3-949 ... 0-1227 12 noon— 3 p.m 100 cc. ... 2-548 ... 0-0792 3 p.m.— 7-30 a.m., Nov. 22 650 cc. ... 12-989 ... 0-1560 1165 cc. 19-486 0-3579 Table XI. Nov. 27, 7-30—8-0 a.m., 0-5 gm. uric acid (0-166 purin N.) TIrine. purin Nitrogen. 10 a.m., 250 cc. 0-0330 2 p.m., 150 cc. 0-0396 8 p.m., 230 00. 0-0606 10-30 p.m., 150 cc. 0-0376 7-30 a.m., 270 cc. 0-0712 Nov. 28, 1050 cc. 0-2420 It will be seen from later experiments, Table XIV., that my endogenous purin-N. is 01625 per 24 hours. During these experiments I ate purin free food, with the exception of 300gms. of veal on the hypoxanthin day. This latter yields about one- half its purin nitrogen as urinary purin-N. (Table TV.), therefore, 0'075 of the urinary purin would be from this source, 0-1625 -h 0-075 = 0-2375. The total quantity of urinary purin after the hypo- xanthin was 0-3579. This, minus 0-2376 = 0-1224 N., directly due to the hypoxanthin ingested. As the N. of 0-5gm. hypoxanthin = 0200, it will be seen that 60 per cent, of the hypoxanthin N". was voided in the 68 THE PURIN BODIES urine during the 24 hours. This confirms similar results by Burian and Schur. Equally, when the uric acid was taken, the purin-X. excretion was 0-2420. On this day, only eggs, milk, bread, cheese and butter were eaten, and the endogenous purin-X. = 0-1625. The difference of 0-0795 came, therefore, from the uric acid: 0-5gm. of uric acid = 0-1666 N"., and hence during the succeeding 24 hours 47-7 per cent, of the uric acid ingested was excreted as urinary purin. It will be shown later, that the remainder was probably excreted as urea. Scetheer and Ibrahim have recentlj^ published experiments showing that uric acid is not absorbed when taken per the mouth. The results obtained are at distinct variance with those of other workers as well as those above stated, and confirmation of Scetbeer's figures are necessary before we can accept them. If the uric acid was not absorbed, it should have been recoverable from the faeces, but this Soetbeer and Ibrahim did not attempt. Neither the total purin nitrogen nor the xanthin bases are given, so that conclusive deduction from their figures is impossible. A noticeable feature of these absorptive lesnltg, is the rapidity of their excretion. Almost the whole of the expected amount of hypoxanthin was eliminated as urinary purin within a few hours. Later experiments have given somewhat similar results, but the subject needs wider application. The administration of these substances might be of use as an indicator of individual purin metabolism. A known quantity given with purin-free food, OF FOOB STUFFS 69 skould, under ordinary circumstances, be excreted as urinary purin to the extent of 50 per cent, in A- hours. The integrity of the liver and kidney cell activities would be a matter of easy induction from the results obtained, and some clue would be gained as to the tonicity of the vascular circulation in these organs. The application of this suggestion will appear more feasible when purin metabolism has been discussed. 70 THE PURIX BODIES CHAPTER VI. The Effect of Continued Daily Injections of PuRiN-BoDiEs IN Rabbits. These experiments were undertakeu with tlie object of recognising any changes in the liver, marrow and nerve cells after the injection of hypoxanthin, etc., and of repeating previous investigations upon the kidney and blood-pressure. Dosage. The quantity injected corresponded with the average daily amount (per kilo) taken by an adult man in his food. This would be a large dose for an animal accustomed to small quantities of purins in its food, but yet not approach the toxic doses of Milroy and Malcolm. It is difficult to con- clude how much Croftan administered, as the weights of the animals are not stated. The results of toxic injections are certainly of value and interest, but as the purin action under general conditions is perhaps more cumulative than momentary, and through overstrain of cellular functions may pro- duce its effect indirectly, an attempt to obtain some less pronounced tissue changes should lead to a better knowledge of cell reactions in pathological metabolism. The injections were made and the operations OF FOOD STUFFS 71 performed at Carolinska Institutet, Stockholm. Four young rabbits were procured six days before the experiment commenced, kept in separate cages, fed on the same daily quantities of oats throughout, and their urine examined regularly. Each day from September 23rd to November 12th inclusive, Eabbit 1 (1480gms.) received 5co. of 0-026 slightly alkaline solution of hypoxanthin (for a man ■weighing 68 kilos= l"133gms.). „ 2 (1546gms.) received Ice. of 0'025 slightly alkaline solution of hypoxanthin (for a man weighing 68 kilos = 0'2193gms.). „ 3 (1713gms.) Ice. of 0'025 of guanin solution (for a man weighing 68 kilos = 0'2193gms.). „ 4 (2025gms.) was employed as a control. The hypoxanthin used for No. 1 was made by the usual process from fresh beef, that for No. 2 was obtained from E. Merck., of Darmstadt. The guanin was prepared from the scales of alburnus lucidus, which, after boiling in 5 per cent. NaOH for four hours, precipitation with freshly-prepared cuprous oxide, and decomposition by HaS, yielded guanin upon the addition of strong ammonia to the HaS freed filtrate. It contained 42'46 per cent, nitrogen (Kjeldahl) and was free from all albuminous material. The rabbits were weighed each day at 3 p.m. Although they all received the same amount of food, while the control animal had gained 145 grams at the end of the experiment. No. 1 and No. 3 had only increased 60 and 52 grams respectively, and 72 THE PURIN BODIES IXo. 2 had lost 206 grams. The effects of the injec- tions were thus reflected in their weights. The control rabbit increased gradually in weight, Xo. 1 gained lip to a certain level and then just managed to maintain it, biit Xo. 2 during the last 20 days rapidljr emaciated. The animal in which guanin was injected was subject to marked diurnal or di-weekly increases or diminutions of weight. On the 43rd day blood films were made from each rabbit, and on the following morning, 4 — 6 hours after a meal, blood pressure tracings were taken. After death, the heart, vessels, kidneys, lungs, marrow, and brain were removed for histological examination, and the muscles boiled with 0'5 per cent. H2>S S "5 <^ s <^^7> ^"(U'^'^ ^":-dM OF FOOD STUFFS 77 these rabbits a distinct cellular reaction was directed against bodies of a toxic nature. The alterations in the liver parenchyma suggest the presence of some exogenous or endogenous cell poison, but certain morbid manifestations may follow over- worked or overstrained organs, and the slowness of growth in rabbits 1 and 2 is somewhat signiiicant. Whether it is reasonable to assume that the purins exert a similar influence in man is hard to say. The exogenous purin in the rabbit is, as a general rule, A-ery much less than in man ; and it could be well argued that human cellular tissues are more immune to these bodies than those of the rabbit. Mitchell Bruce, Bier, Jelks, and many others think that the kidney, cardiac and vascular changes in nephritis are due to an irritant of a chemical nature. Croftan and Kolisch consider that alloxuric bases are the specific irritant, but there is no evidence obtained by reliable methods which substantiates any increased circulation of these bodies in the blood or lymph stream of nephritic patients. At the same time it must be admitted that the purin bodies are not wholly harmless, and any deficiency of oxidation might readily delay the transformation of these insoluble substances into the soluble urate, and so retard their passage into the circulation. The tissues of rabbit No. 3, into which guanin was injected, presented no noteworthy alterations. Kochmann has recently fed several dogs on oxen- flesh alone for six to ten weeks. In one there was distinct loss in weight and in all the liver showed cloudy swelling and fatty infiltration. Broncho- 73 THE PUEIN BODIES pneumonia, acute hsemorrhagic nephritis, cloudy swelling, fatty degeneration and parenchymatous inflammation of the kidney were also observed. The urine contained blood and albumin. Although he raises the question of a possible acid intoxication, his conclusions indicate that excessive flesh food as well as alcohol and lead may cause deficient liver metabolism, kidney degeneration and the conse- quent alterations in the excretion of uric acid. At present there is a tendency to disregard the action of the oxypurins upon the tissues, but it must be remembered that when they are in excess they probably form unusual combinations and that such products may act as irritants. When Kochmann added carbohydrate food to the meat diet, his dogs presented few post-mortem pathological changes. Up to the present date, I have made a large number of personal experiments, and when I have taken large doses of purin bodies — such as |gm. of hypo- xanthin, 1 — 5gm. of guanin, 05 — Igm. uric acid — apparently associated symptoms of general malaise and irritability have frequently appeared. OF FOOD STUFFS 79 CHAPTER VII. The Fate of Food Pueins in the Body. The relation between the ingested food and the simplified nitrogenous bodies of the urine and fseces has been the cause of many experiments and much theory. Practical demonstration of the intermediary stages has been very slow, and it is only within recent years that chemical physiologists have demonstrated the differences between the decomposi- tion products of proteid and nuclein. The view, that during metabolism one portion of the absorbed proteid is first anabolised into living protoplasm and the other undergoes direct katobolism, has been further developed by the belief that as all metabolic processes are intracellular, no katabolism occurs except as a result of cell influence. Whether, how- ever, as some cytologists affirm, the proteid first undergoes entire anabolism, or as others consider, is in part directly katabolised, in both cases, as a result of cellular control, through oxidations, dehydrations, decompositions and perhaps also by synthesis, it is excreted as urea. Wohler and Frerichs, in 1848, from the results obtained by the injection of urates into rabbits, con- sidered uric acid to be an intermediate body between proteid and urea. Amongst many others, Stad- 80 THE PURIN BODIES tliagen, in 1887, thought that uric acid resulted from the cleavage of albumin, and that its quantity was dependent upon the amount of albumin in the food, and Mares proposed a theory of its formation by glandular cells, and its consequent expression of the secretory activity of the body. As late as 1898, the following statement appeared in a well-known book : " The production of uric acid depends upon the ingestion of proteid matter, and it makes no differ- ence whether the proteid matter be of animal or vegetable origin. The only reason that a vegetable diet is less productive of iiric acid than an animal diet, is in the fact that the former is poorer in proteid material. With the same intake of nitrogen in the two diets, there is practically no difference in the uric acid output." On similar grounds is based Latham's theory that uric acid results from the synthesis of urea and glycocin through the stages of hydantoin and biuret. In 1899, however, Taylor showed that the amount of ingested proteid has absolutely no constant relation to the quantity of uric acid excreted, and that even with a proteid-free diet of 350gms. sago, 50gms. sugar and lOOgms. butter, the urine con- tained 0'2T3gms. of uric acid per 24 hours, and Hess and Schmoll liave not found increased purin excre- tion after tlie consumption of even twenty-four hen's eggs, .lerome concluded .from the resxilts of a long experiment, that " there is at present no proof that uric acid can arise in man independently of a sub- stance containing an alloxur or purin group." Maurel, however, recently pointed out that if a con- AViener has lately shewn that from an experhiiental standpoint, a small amount of uric acid, may arise synthetically, but that the quantity is almost infinitesimal. Xuclein, on the other hand, according to the work of Burian and other's, is being constantly formed from the purin-free proteids. OF FOOD STUFFS 81 dition of nitrogen hunger is induced, tlie amount of nitrogen in the food exerts some influence upon the uric acid output. For instance : — Food of 3250 calories with l'25gm. N. per day=0'21 uric acid. 3800 ., 1-00 ,, ,, =0-11 2500 ., 0-50 „ „ =0-07 But as early as 1867 Gorup recognised the import- ance of the nuclein bodies in regard to metabolism, and Kossel, in 1881, obtained xanthin bodies from pure nuclein by hydrolytic cleavage. His declara- tion in 1882, that nuclein might be a source of uric acid with hypoxanthin as an intermediary body led to a series of experiments in which rabbits, eats and dogs- were fed with nuclein bodies, and increased amounts of urinary purins demonstrated. The work of Horbaczewski, who showed that oxidation of fresh splenic pulp by bacterial agencies, produced uric acid of the same nitrogenous value as that of the nucleins of the tissues, and that nuclein prepared from splenic substance, dissolved in weak alkali and digested with blood at 40°C, yielded uric acid, led up to the theory that the decomposition of nuclein in the tissues yielded xanthin and hypoxanthins, and that these bodies, after oxidation, were excreted as uric acid. The increased amount of uric acid, eliminated after meals rich in nucleins and present in the urines of leucocythsemic patients, supported Horbaczewski's further contention that disintegra- tion of leucocytes was the source of uric acid. Parallel examinations of the blood and urine have, however, subsequently shown that leucocytosis does 82 THE PURIN BODIES not regularly accompany increased viric acid excre- tion, and Hutchison and Macleod have recently reported a case of leiicopenia in which the alloxuric urinary nitrogen was of an Average normal amount. "Whilst we may thus regard leucocytic destruction as one source of urinary purin, it probably does not play such an important role as was formerly thought. The supposition of Haig that the urinary uric acid is in part the expression of the uric acid con- tained in the food, may be cited. His conclusions are elsewhere reviewed, although they are not generally accepted. The observations of Weintraud, Maj-er, Umber, Jerome, and Hopkins and Hope have proved that thymus and pancreas, bodies rich in nucleins, cause an increased urinary purin output. As regards the cleavage 'product.^! of miclein, Strauss, in 1896, obtained an increased uric acid excretion after the addition of 50gms. of meat extract to his usual diet, and Jerome recorded varied increases after lamb, steak, mutton, fowl, pigeon and partridge. The methyl-purins of the food increase the total purins of the urine, but only slightly affect the uric acid excretion. Albanese, and Krtiger and Schmidt have shown that these bodies are de- methylated during metabolism, and that the 1 — 3 — 7 methyl-xanthin caffeine is excreted as di- and mono- niethyl-xanthin, and the 3 — 7 di-methjd-xanthin, theobroniin, as 3 methyl-xanthin. All foods containing purin bodies thus appear to increase the excretion of uric acid and the OF FOOD STUFFS S3 xanthins. What theu, is the eft'ect of the piirin-free or p\irm-poor foods? Milk was found by Buriaii and Schur to lesult in a very low uric acid excretion, and casein, aleuronat, and sanose by Rosenfeld and Bornstein, Brandenburg, and Schreiber to produce a similar effect. In this regard the purin excrstion of children fed upon milk is interesting. Camerer reports the case of an unweaned child nearly twelve months old, whose total daily urinary purin = 0'035gm. N., and Bendix obtained 0098gm. of uric acid (0'033gia. N.) from the urine of a three month's old child fed upon cow's milk, and in a child aged seven years I have found 01072 — O'llTO urinary purin jS^. on a milk diet, and 0'1570 — 01600 on a mixed diet. Camerer estimated the effects of food upon purin excretion and arrived at the follow- ing results : — Urinaiy Purin N. A diet of milk, cream, eggs, meat and coffee =0'72 „ peas, cabbage, fat, bread, butter and beer = 0'4:l „ potatoes, chestnuts, fruits, bread, butter, honey, meal and milk =0'36 „ meat, fruit, vegetables, eggs and cheese... = 0' 66 As coffee and beer were taken, it is impossible to draw any adequate conclusions as to the exact effect of these diets. Taylor found : — Uric Acid Bases On a mixed normal diet 0-364 0-0249 plus sweetbread 0-871 0-0271 „ much proteid 0-456 0-0134 „ peas and beans 0-462 0-0195 „ nitrogen free food 0-273 0-0066 84 THE PUEIN BODIES Hence we may infer that with certain foods a minimum of uric acid is excreted, and that as such foods probably contain little purin, they make but a slight addition to the uric acid which the body produces independently of the nucleins of food- stuffs. Siven, in 1900, on a fixed diet, fiirnished experimental proof of such a conclusion, but to Burian and Schur is the credit due for its substantia- tion through their estimations of the purin-N. of certain foods. Their results are as follows : — Purin nitrogen Purin X Brown bread 0-010% Thymus 0-386% Milk 0-004% Liver 0-123% Potatoes 0-0005% Beef 0-063% Veal 0-057% Ham 0-063% In white bread, rice, eggs, salad and cauliflower, they found no xanthins. By use of these latter foods they determined the endogenous urinary purins in a number of cases, and obtained results of individual constancy. When the endogenous urinary purin was estimated, and the amount of the food purin also kno-wn, they were able to explain the relation of the food purin to the urinary purin, and knowing the amount of the food purin and the total urinary purin, they were able to calculate the qviantity of endogenous iirinary purin. They state that with beef and liver one-half, with thymus one- fourth, and with coffee one-third of their purin-Jv". appears in the urine as uric acid and xanthin bases. The xanthin bases have not received much OF FOOD STUFFS 85 attention as to tlie cause of their occurrence in the Tinne. They are present only in small amounts, and research has been mainly directed to the investiga- tion of uric acid. The terms bases and acid are, hovever, in this connection somewhat misleading, as uric acid is a tri-oxy-purin, and xanthin and hypo- saiithin are respectively di- and mono-oxypurin, herce their relation is closer than their names sigaify, and they should be estimated together. Milroy has recently recorded the interesting fact that in birds there is always a small but definite laily output of purin bases, although the uric acid excretion is mainly synthetic in origin and but little influenced by feeding with nucleic acid. The Metabolism of Meat Pueixs. The publication, in 1900, of Burian and Schur's interesting researches, led to my investigation of the metabolic changes occurring after the ingestion of those substances, other than thymus, liver, veal, beef and ham, which my earlier estimations had shown to contain considerable amounts of purin bodies. At first sight, it must be supposed that no differences would be found, but as the flesh of certain animals (rabbits, etc.) contains methyl-xanthins, actual results appeared preferable to inference. S^ihject of experiment: W.H., weight, 70 kilos (list. 5lbs.). Urine free from albumin and sugar. The 24 hours' collection was taken from and to 8 a.m., and the urines were preserved for repeated estimations by the addition of a few drops of CHCl . During the experiment ten hours' laboratory work was per- formed, and a walk of four English miles taken each day. 86 THE PURIN BODIES To obtain the average amount of endogenous piirin excretion, a fixed purin-free diet, consisting of eggs, bread, milk, cbeese, butter, rice and sugar was selected. Neither tea, coffee nor beer was taken. Table XIII. gives the results, and indieaies the variations in the calorific and nitrogenous values. Table XIII. Food Uriniry Days Diet Calories Nitrogen PuriE N Approximate 1. 10 eggs, 360gTn. bread, lOOOco. milk, 80gm. cheese, GOg-m. butter 2631 22-38 0-1611 2. 10 eggs, 300gm. bread, lOOOcc. milk, SOgm. cheese, GOgiii. butter 2490 21-60 0-1608 3. 10 eggs, 300g-m. bread, lOOOcc. milk, SOgm. cheese, 60gm. butter 2i90 21-60 0-1560 i. 8 eggs, 360gm. bread, lOOOcc. milk, 80gm. cheese, 60gm. butter, lOOgm. rice, 50gin. sugar- 3053 20-50 0-1636 5. 8 eg-gs, 360gm. bread, lOOOcc. milk, SOgm. cheese, 60gm. butter, lOOgm. rice, 50gm. sugar 3053 20^50 0-1660 6. 8 eggs, 360gm. bread, lOOOcc. milk, 40gm. cheese, 60gm. butter, 50gm. sugar, 50g-m. rice 2898 17-80 0-1563 7. 8 eggs, 360gm. bread, lOOOco. milk, 40gm. cheese, 60gm. butter, 50gm. sugar, oOgm. I'ice 2898 17-80 0-1654 8. 8 eggs, 360gm. bread, lOOOco. milk, 50g-m. sugar, 50gm. lice, 40g-m. cheese, 60gm. butter 2898 17-80 0-1645 OF FOOD STUFFS 87 It thus appears that upon an almost purin-free diet an average of 0'1623gnis. purin-N. per day was excreted, or 0'4869gms. in terms of uric acid and xanthin bases, or 03645gm. iiric acid and 00950 xanthin bases approximately. Such amount is apparently uninfluenced by slight alterations in the quantities of nitrogen and the calorific values of the food. These results are in accordance with those of Hirchfield, Siven and Burian and Schur. In each set of experiments, however, the details differed. Siven and Burian and Schur maintained an unchanged caloric food value, with marked nitrogen variations. Hirschfield added 57 per cent, nitro- genous material and 22 per cent, calories. In my experiment I kept the nitrogen at a constant level and added 22 per cent, of calories. In all cases the urinary purin showed a constant excretion in spite of the changed dietary. The food was, it may be noted, invariably purin-free. In Table XIV., the same fixed purin-free diet was taken, with the addition of certain meats whose amounts are separately noted. That the effect of the increased purin ingestion might be at once evident, the principal meal was taken at 7.45 a.m., when the larger portion of the meat was eaten. A light lunch preceded the next meal at 4 p.m., when the remaining purin-rich food was consumed. Bed 10 p.m. The meats were weighed raw, then steaked with fat sufficient for the purpose, and every particle of gravy, etc., preserved. 88 THE PURIN BODIES M P5 O O O !> ^ O CO lO ■-" "* -*^ t^ CO lO .I' 6i 4 CD X-- oo CO CO CO r^ -^ ■^ r* t^ CO CO CJO CTJ to oa -^ m 00 t- CO o 5c* * t--QOC .-i(M-^*cDi>.a:icDCNcocNoco r-_\ ^O TJHCO.— i-^tNC3:)CD'M'-HiO(MCO(N(NI>-C^CNO C-l .2 is' ' ' l^rHfMr-lrH-;-!— lrHC^rH--^,-lr-H.-HpHr-l--^(N ^g oooooooooooooooooo f-.fl0505(NQO--HOOOGOoa:>iOCDOQ001r^CO-*00 lOLT^p 35>cocoi>-0'-HOioo:>co°oiocoooaicDmcoiO'— * i -^t^ — Ph ™l:^ I>.-rt<(MtOCDcDt-iO-*t-tD-*COCDOOin)COooooo .S'^o.— (i-Ht-fMio^ooi— i-^-— -'' Uric Acid Purin- bases. Phosphorus. Urea. 112 THE PUEIN BODIES Without committal to the precise details, of whicli we are still in ignorance, the above diagram probably represents the course of the exogenous purins in the body. It will be seen that the exogenous nucleins simply pass through the body. Their phosphorus may be retained for synthetic or organic purposes, and the small amount of albumin they contain may be used up in the tissues, but their purin contents are not employed in the synthesis of cell nucleins. Through some decomposition of the purin ring, a definite proportion of the purin bodies are liberated, oxidised and excreted as uric acid, and the remainder eliminated as urea or as bodies intermediate. Kaufman and Mohr, from recent experiments, have concluded that the extent of this cleavage depends upon the individual and his daily disposi- tion, but the majority of current studies show that the variations lie between 40 and 60 per cent, of the total purin taken with the food, and these constants suggest rather that the constitution of the purin nucleus or polymerisation of the cleavage products play a prominent part. Soetbeer and Ibrahim have lately published the experiments which led them to conclude that uric acid after ingestion or injection is almost entirely excreted as such by man. According to their figures they obtained 80 — 98'9 per cent, of the uric acid from the urine after subcutaneous injection of l'26gm. of uric acid dissolved in piperazine. As will be seen from the following table taken from their OF FOOD STUFFS 113 results, the inferences they make are hardly per- missible. Average for 20 previous days 0"3345gm. urinary uric acid nitrogen. Day of experiment, injection of 0-42gm. uric acid N. ... 0-6739 Following days O'ilOG 0-4518 0-4283 0-4283 Burian und Schur, discussing these experiments, remark that if the excess of the four following days over the average of the twenty previous days be added to the increased amount upon the day of experiment, then 171 per cent, of the injected uric acid was eliminated. It is probable that the average should be 0-4297gm. uric acid, and then 58-1 per cent, of the injected uric acid would have been excreted as such in the urine. If the average, how- ever, was really 0-3345gm. uric acid 'N., then it is apparent that the uric acid was decidedly toxic and led to an immediate increase of the endogenous uric acid and this increased excretion continued for several days. The results of Soetbeer and Ibrahim appear after all to support the previous statement, that 50 per cent, of the exogenous purin bodies are oxidised to uric acid and 50 per cent, are further broken down and excreted as urea or intermediate bodies. m THE PURIN BODIES Endogenous Pueins. The sources of endogenous purins are probably numerous and the quantities derived from each may vary with the hourly activities and daily needs. Although our present knowledge upon this point is somewhat inadequate, we may be sure that in pathological conditions alterations in any one of the factors may lead to diminution or increase of endogenous purins. So far as experimental results can suggest normal action one portion of the total endogenous purins is broken down to urea and the remainder excreted as uric acid. Abnormal endogenous purin metabolism may, therefore, consist in an increased production with excessive or diminished destruction, or in decreased production with excessive or diminished destruction. Hence arises the diflSculty of any correct inference from the results of endogenous piirin elimination. Constancy of endogenous purin excretion points to normal metabolism and the maintenance of the several factors concerned. Variations in the endogenous iirinary purin of the same individual upon a fixed diet indicates altered relations of the contributory functions. The table on p. 115 will perhaps give a broad idea of the origin, course and fate of the endogenous purins within the body. How is the nucleoproteid transformed into the simpler purin bodies? In the laboratory, the pro- cesses used for such purpose are lengthy and elaborate, and cleavage products, such as pentose, xylose, hexose, albumin, phosphorus, pyrimidin OF FOOD STUFFS 115 derivatives, cytosin, uracil, and nucleotin phosplioric acid are obtained. Is there in tte body a direct splitting of nuclein into uric acid, or is uric acid only an end product of the mono- and di-oxyxanthins ? In what way is kataholism OHIGIN AHD FATE OF ENDOGENOUS PURINS OR NUCLEINS. Leucocytes. Red blood-corpuscles. Gland-secretions. Cell Nuclei It cleavage (Synthesis^) CELLS. TISSUES. Blood. Spleen- Muscles Liver LIVER. KIDNEY. U/tlNL ENDOGENOUS NUCLEINS OR PURINS Bound. Huclein Nucleic acid. Free. Jtanthm. Hypoxanttiin. Purin- bases, moncxypurin di-arypurin. Phosplioric arid Nucleotin - Phosphoric acid /organic \ line acid (combination) Hmmonmm Carbamate. (organic combsnatien removed) Uric acid Purin- bases Urea Phosphorus 116 THE PURIN BODIES affected by pathological conditions? Do ferments play an active part, or are physico-chemical pro- cesses more usually employed? These questions suggest the extent of an unexplored and a difficult field. When we take up the subject of the circulation of purin bodies in the blood-stream and tissues there is more evidence to cite. Without doubt the presence of uric acid can be demonstrated in the blood of patients suffering from certain diseases, but in healthy blood the general tests for the presence of uric acid are not applicable. Substances there exist which interfere with the action of these tests, or the uric acid and xanthin bodies circulate in loose combination with some organic corapound. It has been shown that the addition of certain reagents to solutions containing uric acid entirely prevents or markedly hinders the precipitation of the purin bodies, and the suggestion of Minkowski that uucleotin-phosphoric acid forms the medium for their transmission certainly deserves further thera- peutical application. After large doses of food purins, or in those conditions in which the purin bodies are present in excess in the blood stream, the administration of certain organic compounds might lead to a loose combination which would favour elimination and prevent uratic infiltration. It is more than probable that the form in which the purin bodies exist in the tissues is more produc- tive of pathological lesions than the quantitative excess. When one remembers how varied is the composition of the blood in different parts of the OF FOOD STUFFS 117 system — liere venous, there arterial, here containing much CO3 and excretory products, there much oxygen and nutrients, it is conceivahle that few organic compounds can exist in a permanent form. Hence it is not unlikely that we may ultimately abandon to some extent our conception of bi- and quadri-urates of soda and substitute therefor the thesis of uric acid organic combinations as a necessity for their normal circulation. If we allow such a possibility, then some idea may be gained of the resultant eifect of the presence of the imperfect metabolites in the tissues, and our therapeutics be directed to the restoration of normal metabolism and consequent freedom from imperfectly metabolised bodies, rather than to the attempted solution and elimination of uric acid. When uric acid exists in normal combination, it does not irritate the tissues, but if the blood contains abnormal substances and consequent altered osmotic and physico-chemical conditions prevail, necrosis and uratic infiltration frequently result. A large number of uric acid compounds have been obtained in the laboratory and some of them are isomeric. May not a similar number occur within the body, and perhaps some individual combination be responsible for the particular symptoms and lesions which certain families or persons exhibit? The seat of the endogenous uric acid formation has been assigned by numerous workers to the spleen, kidney and liver respectively, but Mendel and Jackson consider that in mammals no one organ alone per- forms such functions. Its destruction, according to 118 THE PURIN BODIES recent work upon the subject, takes place mainly in the liver, but Wiener, working with organ extracts, showed that such prepared from liver, kidneys and muscles were able to decompose uric acid. If his methods were reliable and his experiments correspond to intra-vitam processes, the tissues generally may share in the uric acid destruction. But the role of the latter must be small compared with that of the liver, and to this conclusion the later experiments of Burian und Schur distinctly point. Probably, there- fore, the exogenous purin-remainder is decomposed chiefly in the liver, perhaps partly in the tissues, and finally excreted as urea, or as bodies intermediate. The endogenous purin may undergo similar meta- bolism, and only 50 per cent, of the total quantity appear as such in the urine. Table xxi. may be appended as a contribution to our knowledge of its source of endogenous purin, as it indicates a relation between the body weight and the endogenous purin excretion, and points to the probability that the endogenous purin is the expression of that amount of nuclear or protoplasmic activity necessary for the maintenance of cell functions. Table XXI. Endogenous Age Weight Urinary Purin Infant... 8 days ... 4'5 kilos. ..0-0170 Uric acid-N. ...Mares. „ ... Smths.... 5- „ ...00330 „ „ ...Bendix. ,, ...12 „ ... 8- „ ...00350 total purin-N....Camerer. Female... 7yrs. ...22- ,, ...0-1200 „ „ ...Walker Hall. „ ...32 „ ...48- ,, ...0-1450 „ „ ...Walker Hall. Male ...23 „ ...68- „ ...0-1530 „ ,, ...Burian. ,, ...32 „ ...70- „ ...0-1625 ,, ,, ...Walker Hall. „ ...28 „ ...77- ,, ...0-2020 „ „ ...Burian. OF FOOD STUFFS 119 Burian und Schur in tHeir recent work point out that this tatle, while indicating a relation between the body weight and the endogenous purin excretion, tells little as to the source of the purin. The origin of tissue nucleins is much more complex. This must be admitted, as so few other figures are at present available, but if further estimations confirm these results, such a relation would make a useful basis for clinical practice. B. Mendel informs me privately that he has col- lected a number of new purin estimations, and that his figures correspond, particularly in the case of children, with the above table. 120 THE PURIN BODIES CHAPTEE VIII. The eole of Puein Bodies ix Moebid Conditions. Although healthy blood does not apparently contain uric acid, its presence has been fully demonstrated in the following diseases : — Pernicious Ancemia. Salomon, "Zeit. fiir Phys. Chemie.,"' S. 65, 1878. Leukcemia. Klemperer, " Untersuchungen iiber Giobt.," S. 3, 1896. Anmmia and intestinal inflammation, v. Jaksch, " Deut. Med. Woch.," S. 33, 1890. Fevers. Malaria, between the attacks. „ S. 33, 1890. Typhus, after febrile stage. „ „ Gout. Garrod, nature and treatment of gout, 1861. M. Levy, " Verhand. f. Cong. f. d. Inn. Med.," S. 266, 1896. Liver. Carcinoma, v. Jaksch. Nephritis. Garrod, lOOcc. blood = 4mg. ur. V. Jaksch. Levy, "Virchow's Archiv.," S. 107, 1898, 12 cases. Klemperer, in ursemic conditions. Plumhism. Oliver, " Goulstonian lectures," 1891. Pneumonia, v. Jaksch. OF FOOD STUFFS • 121 In cardiac, nephritic and pleural exudations it has also been found, and Bouchard identified it in the nasal, pharyngeal, stomach, bronchial, vaginal and uterine mucus and the lachrymal secretions during ursemia. Numerous estimations of urinary purins have been made in nearly all known pathological conditions, but only in the following have any distinct variations been demonstrated. Nephritis has yielded irregular results : — Pathological Increases of Urinary Purins. Ukic Acid : Alcoholism with enlarged liver. Strauss, " Zeit. fur klin. Med.," p. 319, vol. 31. Carbon monoxide poisoning. Miinzer, " Deutsch. Archiv. f. klin. Med.," p. 236, vol. 62. Cirrhoses of liver, v. Noorden, " Lehrbuch," p. 288. Also in a case of acute yellow atrophy. Gout. M. Levy, "Berlin, klin. Woch.," p. 389, 1896, during and immediately after acute attacks. Leucocythcemia. Eanke and many others. Neurasthenia and Migraine. " His W., Verhand-Cong. f. inn. Med.," 1896. Pneumonia. Herter and Smith, " New York Med. Journ.," 1892. Sepsis. V. Jaksch, " Cbl. f. inn. Med.," p. 188, 1896. Scurvy, v. Jaksch, " Cbl. f. inn. Med." p. 188, 1896. Xanthins : Adipositas. Schreiber und Waldvogel, " Arch. f. Exp. Path, und Pharm.," 42, S. 74, 1895. 122 THE PURIN BODIES Diabetes. Baginsky und Sommerfeld, " Zeit. fiir Phys. Chemie., S. 412, 1895. Diphtheria. Baginsky und Sommerfeld, " Zeit. fiir Phys. Chemie.," S. 412, 1895. Scarlet fever. Baginsky und Sommerfeld, " Zeit. fiir Phys. Chemie.," S. 412, 1895. Nephritis. Kolisch and Tandler, " Stuttgart," 1895. Croftan, " New York Med. Journ.," Aug. 11, 1900. Thyroidea. Schreiber und Waldvogel. Pathological Decreases in Ueinaey Pueins. Uric Acid : Ancemias. Brandenburg, '" Berlin klin. Wocli.," S. 137, 1896. Honigman, " Cbl. f. inn. Med.," S. 873, 1897. Taylor, Loewy, " Cbl. f. inn. Med.," S. 188, 1896. Gout. Decrease 1 — 3 days previous to attack. His (I.e.) Vogt. S. (general decrease) " Deutsche Archiv. klin. Med., S. 21, 1901. Dependent upon the extent of diuresis, variations occur in cardiac diseases, and in epilepsy and chorea. In diabetes, any increase is usually the result of excessive intake of meat purins. In certain fevers, leucopenia, phthisis, and the intermediate stages of gout, the uric acid excretion is normal. These variations result from the balancing of pro- duction and destruction, or of production and excre- tion. Unfortunately, the great mass of statistics available for reference supply little distinct and OF FOOD STUFFS 123 decisive evidence; for until recently, diet was not considered in relation to tte results obtained, and although the newer experiments give details of the food taken, there exist hut few investigations in which the purin contents of the dietary have heen estimated, and the reaction they incite, seriously recognised. It is even now generally thought that in gout the exogenous uric acid formation and excretion are normal, except before and after the acute attacks, and Watson has demonstrated the fact by feeding a gouty patient upon thymus and nucleic acid, obtaining an increased uric acid elimination, and inferring that the nuclein metabolism was normal. The average daily uric acid was 0'307gm. Thymus contains about 0'4 per cent. purin-lST., of which one-fourth reappears in the urine as uric acid. On January 6th and 7th, 280 gms. of thymus were given, and the total uric acid excretion was 0'730, or 0"242 uric acid nitrogen; 280gms. of thymus contain l'12gms. purin-N., of which 0.28 may be expected to appear in the urine as such. If we take the average excretion of 0'307, the total for the two days would be 0614 uric acid, or 0'205 uric acid N., and the difference between 0242 -0-205 = 0-037 might be considered as due to the thymus. But 280gms. of thymus yield 0'28 exogenous urinary purin. Similarly, on January 9th, 252gms. of thymus were administered, and the uric acid was still only slightly increased. There is no record of the total purin nitrogen or the xanthin bases, so that one cannot draw the conclusions desired, but if the many in- vestigations upon the effect of thymus upon meta- 124 THE PURIN BODIES bolism are correct, it is improbable that tbe patients' purin metabolism was normal, and possible tbat con- siderable retention occurred. We can now, however, by aid of the average purin percentages of Tables iv. — viii., and the knowledge of the metabolic results recorded in Table xiv., deduct the exogenous portion from the total urinary purin, and so obtain the endogenous factor, or by the observations of a diet containing only purin-free foods, directly estimate the endogenous purin. As we may thus definitely assign some portion of the urinary purin to the presence of purins in food, we m.ay, as the results of this investigation demonstrate, control the individual nuclein metabolism in its relation to purin ingestion by prescribing a dietary based upon quantitative purin estimations. Hence, so far as the reactive processes are concerned, the practitioner should now be able to precisely spare or stimulate his patient's metabolic powers, and under both conditions prognose the character and the in- tensity of the endogenous metabolism. To this end, indeed, further studies must now be directed. The experiments herein described have shown the import- ance of diet in its relation to uric acid, and the ease with which we may arrive at the amount of uric acid produced by the body itself, so that the future deter- minations of urinary purins should have for their object the attainment of definite factors for the endogenous purins, a knowledge of the circumstances that affect their variation, and the acquisition of data as to the rapidity and completeness of the individual exogenous purin metabolism. New estimations of OF FOOD STUFFS 125 tlie purin excretion in many diseases are by these conclusions rendered absolutely necessary, and tbe results therefrom should lead to more accurate conceptions of those metabolic changes, compensatory or otherwise, which probably accompany all patho- logical processes. The tendency to ascribe to uric acid a causative influence in the majority of the known diseases may be attributed to an over- enthusiasm, which has sadly enough induced much apathy upon any subject connected with uric acid, and consequently led many to under estimate its role in the economy. When, however, pathological chemistry becomes gradually narrowed to the appreciation of cell-reactions, it may direct attention to the nuclear changes as the expression of the dominating factor in cell life, and compel us to regard the endogenous purins as the more important indicator of metabolic processes, and the decomposi- tion of proteids as dependent upon the energy liberated by the cleavage of cell-nucleins. Kaufmann and Mohr have recently published some estimations of purely endogenous purins in certain pathological conditions. One cannot, of course, compare them with similar results obtained from healthy persons and make conclusions there- from, but the figures are exceedingly useful as the first of a new series. The following are a few typical cases : — 126 THE PURIN BODIES Total Urinary Sex Age Weight Purin N Disease emale .. 17yrs . .. 41kg. ... 0-137 .. Scarlet Fever „ .. 18 „ . . 49kg. ... 0-181 .. Hsematemesis ?) .. 20 „ . .. 47kg. ... 0-115 .. Gastric Ulcer ale .. 21 „ . . 54kg. ... 0-213 .. Perityphlitis jj .. 23 „ . .. 62kg. ... 0-200 .. Abdominal Pain -*> ... 36 „ . .. 64kg. ... 0-190 .. . Gastric Catarrh In gout the same observers and also Vogt con- ducted metabolic experiments and found an increase of endogenous purins immediately before and during the acute attack. During the intervals the excretion approached the normal. It is, ho-vrever, exceedingly- difficult to make satisfactory deductions from the excretions of different patients. Ho-w far these statements may be applied to individual cases is not at present known ! The general inference that in gout there is little retention except during the acute attacks is permissible, but accurate figures are only possible by comparison of the excretions of the same individual at varied intervals and under altered cir- cumstances. For the formation of tophi, marked urate retention is unnecessary, as these accretions are only formed slowly and are most probably due to local rather than general lesions. When the kidney is involved, the uric acid excretion is slightly altered, but it is in no sense comparable with the marked variations of the urea and albumin which occur. Exogenous purins are, as a rule, badly metabolised by gouty individuals. This has been recently observed in a case by Reach. It will be shown later that uric acid cannot be " washed out " of the system. Substances that solute uric acid in OF FOOD STUFFS 127 the test tube are of little or no use in increasing the output of uric acid in the body. When drugs do increase or diminish the uric acid excretion, they act by directly affecting the cellular processes of the body and not by dissolving out the uric acid deposits. In leucocythsemia the formation of endogenous purin is excessive and the urine contains very large quantities of uric acid. In this case the endogenous purins are probably diminished by the anaemia and its consequent tissue malnutrition, and augmented by the formation and destruction of enormous numbers of leucocytes. The increase of uric acid in cirrhoses of the liver is somewhat variable and new estimations are required. Here it is probable that there is decreased destruction of uric acid in the liver. In neurasthenia and migraine, excess in uric acid elimination has been observed. Whether this be- tokens loss of nervous control or irregular nervous stimulation is not clear. In either case there is room for extended enquiry in this direction, and results obtained by the use of recognised methods should be useful as regards the prognosis of both the meta- bolism and the nerve lesions of the patient. Still, at the moment, the source and function of the endogenous purin are not clearly delineated. A small portion may arise from leucocytic destruction, but distinct evidence of any other origin, although at present unavailable, will doubtless soon be furnished. Apart from theoretical considerations it is certain that diseases of perverted metabolism are frequently accompanied by abnormally increased or decreased 128 THE PURIN BODIES excretion of urinary purin, and just as the secret of successful treatment in tuberculosis depends on its early recognition, so the radical therapeutics of metabolic diseases will depend upon our better knowledge of their earlier stages. Let the now fashionable precepts of individuality in treatment have further application in the practical recognition of a personal factor in the normal and compensatory chemical processes which occur in the human body, and the necessity for lifelong studies of patients and their families becomes at once apparent. Who is to obtain the information as to the metabolism of children of gouty parents and its alterations during their growth? The laboratory worker is unable to make material advances along this line, for the cases he is able to investigate are principally those of healthy, abstemious adults, with perhaps a sprinkling of kindly disposed patients. It is the clinician who alone can furnish the necessary information and statistics. If one be permitted to further indicate the lines of such research, I would remark that opportunities to estimate a patient's endogenous purin, and occasions for systematic determinations of these factors from year to year in children of certain diatheses, must occur to many practitioners. The accumulation of such statistics would not only contribute to our general knowledge of these processes, but would often throw much light upon local conditions. The occurrence of abnormal quantities of the santhin bases in the urines of nephritic and gouty patients has been pointed out by Kolisch and others, OF FOOD STUFFS 129 but their results were obtained by the (for this purpose) inappropriate Kriiger-Wulff method, and as His and Schmoll have failed to find any such increases in gout, additional work is necessary before the theory of the causation of nephritis by alloxur bodies can be accepted. The opponents of the theory are not, however, justified in their denial of its probability. Already cited facts certainly show that in rabbits, unaccustomed to much purin in their foods, degenerative tissue changes occur, and normal growth is hindered. Whether these are due to direct toxic action, or to cellular exhaustion consequent upon overwork, is a matter not yet decided. But Mitchell-Bruce and Bier are both agreed that meta- bolic perversion throws extra strain upon the vascular and excretory organs, and as a result of some chemical irritant, the heart hypertrophies and possibly the kidney degenerates. The relation, if any, between such excitant and the food purins, is a subject which I hope to further investigate. Croftan has recently published an interesting paper upon the role of uric acid in morbid conditions. He points out that the accumulation of uric acid in the tissues is simply one of the symptoms of gout, and must not be taken as its cause. The intravenous injection of uric acid into animals caused immediate intra-cellular changes and the excretion of 80 — 90 per cent, of the uric acid in the urine. He also examined the uric acid destroying quotient of the liver, kidney, muscle, blood and spleen after the removal of these tissues from the body. The human kidney appeared to destroy more uric acid than the 130 THE PURIN BODIES liver, and the muscles more than either the liver or kidney. The presence of salicylates and alkalies accelerated the destruction. He ascribes these results to the action of unorganised soluble ferments, and considers that his experiments favour the renal theory of gout and that the relation of obesity, gout and diabetes, arises from the fact that the organs which destroy uric acid equally catabolise fat and carbohydrates. The association of oxaluria with diminished uric acid excretion, and the presence of these conditions in gout is also dealt with. There is no doubt that Croftan's experiments are ingenious and important, and differ from other workers in the inclusion of human organs ; it is at the moment difficult to apply the figures, as we do not know much of the changes which occur during the autolysis of glandular organs and in what ways the available ferments can vary their usual actions. OF FOOD STUFFS 131 CHAPTER IX. The Actiox of Dkugs upon the Elimination of PuEiN Bodies. The view Avhicli regards uric acid as the actual and only mate lies morhi in gout and allied disorders, still largely prevails; consequently, mucli therapy is directed against this necessary result of nuclein metabolism. Fashion has decreed the use of numerous drugs in the active and prophylactic treat- ment of these conditions and the value of each medicament has been measured in terms of its solvent powers for uric acid in the test-tube, quite regardless of the fact that it could not be safely introduced into the blood in sufficient quantities to exercise its soluting properties. The following table shows a few of the results obtained by the use of these much vaunted remedies. Bain, W. " Brit. Med. Journal," p. 243, 1901. BoMand, K. " Miinoh. Med. Woch.," s. 505, 1899. Goodbody, F. W. " Journal of Physiology, p. 414, 1899. Good, C. " American Journal of Med. Sci.," p. 274, 1903. Huber and Lichenstein. "Berlin. Klin. Woch.," No. 28, 1 902. Hupfer, F. " Zeit. f. Phys. Chemie.," s. 303. Bd. 37. Kumagawa. " VirchoVs Archiv," s. 192. Bd. 113. Laquer,B. "Verhandf.d. 14 Cong. Inn. Med.," s. 333, 1896. Leber, H. " Berliner Klin. Woch., s. 957, 1897. Lewandowsky, M. " Zeit. f. Klin. Med., s. 202, 1900. Salkowski. " Virclaow's Archiv, s. 573. Bd. 117. Schrieber und Waldvogel. "Arch. f. Exp. Path.," s. 69. 42. Singer, H. 'Arch. f. d. Ges. Phys.," s. 527. Bd. 84. 1901. Weiss, J. "Zeit. f. Phys. Chemie.," s. 216. Bd. 27. 1899. 132 THE PURIN BODIES c j; . UTtIC ACID. Observei". Diet. , 1 Average Average J ^^,^^^1- Iiicrease. | ^^^^^ Remarks. Water Laquer y y 10% — Alkalies 1. 9 ? — 0-020 gni Homburg "Water . . Lebers days Fixed mixed 0-173 gm — three days later decrease of 0-109 gm SodiumAcetate lOgm Salkowski _ ■} — 0-285 gm supposed diminished formation ,, 13 gm Kumagawa . . _ Fixed mixed 0-054 gm — in dogs „ It) gm It — Fixed mixed 0-064 gm — ,, Benzoate 3 gm Schreiber 3 days Fixed mixed — — ^ gm Lewandowsky 2 days Hospital diet — — 1' >i '' gm ,j 5 days Hospital diet 0-032gm — ,, Salicylate 3 gm Ulrici 3 days Fixed mixed — ■ 0-049 gm nitrogenous equilibrium maintained 3gm Schreiber 4 days ? 0-252 gm — . 3 gm 1! 3 days Vegetable diet 0-097 gm — ! > ! ) * gm ,, 3 days Vegetable diet 0-140 gm — n 1 gm Goodbody . . 4 days Fixed mixed 0-065 gm — 2gin n 9 days Fixed mixed 0-078 gm — 2 gm Jl 9 days Fixed mixed 0-250 gm — n y, ^> gm Lewandowsky 3 days Hospital diet 0-207 gm — Lithium Good — — — __ without any influence ,, Benzoate 45 grs Bain 4 days Fixed meat 0-017 gm _ Acid Tannic . . 3 gm Boland 4 days y — 0-287 gm ■ ■ 3gm Ulrici 3 days Fixed meat 0-067 gm ■ — nitrogenous equilibrium ,) 1, - (>ffm M 6 days „ — 0-298 gm „ Gallic . . S gm 11 3 days Fixed meat — 0-049 gm nitrogenous equilibrium ,, Benzoate 8 gm 11 3 days Fixed meat — 0-049 gm ni trogen ous equilibrium ,, Quinic . . S gm I. 3 days Fixed meat — — nitrogenous equilibrium ,, .. 6 gm Oewandowsky i days Hospital diet — 0-045 gm ■■4 gm Hupfer 4 days Fixed mixed 0-0] Ogm — Aspirin . . . . 3 gm Singer 2 days 9 0-273 gm — big fall afterwards Atropin . . 2 mgm Bohland i days V — 0-148 gm Colchi-sal 9 capsules Bain 4 days Fixed meat __ 0-013 gm aromatic sulphate high Lysidine . . 45 grains 11 4 days Fixed meat VllOgm — „ .. 1 gm Goodbody . . 4 days Fixed meat — — . . 2 gm jj -i days Fixed meat — — .. 1 gm 4 days Fixed meat 0-018 gm — Piperidin, 30 grains Bain 4 days Fixed meat 0.017 gm — slight rise afterwards Tartrate Piperazin 45 grains 1. 4 days Fixed meat 0-064 gm — aromatic sulphate diminished Sidonal 75 grains ti 4 days Fixed meat 0-126 gm Piperazine quinate Sidonal, Neu. 10 gm Huber 5 days Fixed meat 0-116 gm Quinic anhydride Urosine Weiss — — — said to diminish urio acid excretion Urotropine 30 grains Bain 4 days Fixed meat 11-03 gm — OF FOOD STUFFS 133 A glance at the above figures shows that the uric acid output is only slightly affected by drug adminis- tration. If we take 0'3750gm. as an average uric acid excretion upon purin-free food, then upon a mixed dietary the average output may be anything from 09 to 1'2 grms., dependent upon the amount of exogenous food-purin. As the bulk of the above 3xperiments were conducted upon patients taking meat, the variations recorded are quite insignificant. Only salicylate of soda yielded a distinct increase. Any excess or diminution in the urinary uric acid may be due to alterations in the amount destroyed by the liver, and it is at present beyond our knowledge to assign the exact cause of these variations, so that when the food contains large amounts of uric acid yielding bodies the question is extremely complic- ated. Thus, although some of the above experiments were conducted under the conditions of nitrogenous equilibrium, until similar experiments upon the same individuals taking purin-free food are available, it is impossible to make any deductions as to the causes resulting in the slight variations recorded. In the case of sodium salicylate, however, Schreiber gives the figures obtained from an experiment in which the subject took vegetable food only, and I have nearly ready for publication a similar case in which the patient was fed upon purin-free food and in which the purin excretion was increased about 50 per cent, after the administration of sodium salicylate. Six months earlier the same patient had taken 45 grains of sodium salicylate each day and a similar increase of uric acid output occurred, 134 THE PUBIN BODIES although on the davs selected for comparison there was a temperature of 99 — 100°F. It appears, there- fore, that when sodium salicylate is administered to a patient upon purin-free food, the endogenous puria or uric acid is at once increased by about 50 per cent, and upon its cessation the uric acid immediately becomes normal. In those experiments in whicli nitrogenous metabolism was maintained, some observers found a distinct urea increase, and con- cluded therefrom that the drug led to considerable disturbance of the nitrogenous functions and to in- creased leucocytosis. When, however, we eliminate the exogenous purin from the question, it is extremely improbable that the leucocytosis or increased tissue destruction would account for the augmented uric acid output. Although further experimental proofs are necessary, it is quite conceivable that this excess purin excretion is due to a synthetic formation and not to any retained products or ordinary cell processes. Luff has already arrived at the same conclusion from a different standpoint; his thesis as to the union of glycocine and urea in the kidney is as yet unproved. The liver is the more likely organ. But his infer- ence that sodium salicylate increases the amount of circulating purin bodies and hence is contra-indicated in gout and for patients with uratic deposits deserves wider appreciation. One thing is certain — salicylate of soda does not wash out retained uric acid and it cannot be employed for such a purpose. Tannic and quinic acids appear to reduce the purin output, but in the cases recorded above a mixed diet was employed, and it is therefore impossible to con- Tattersall and fJies {Aj,i,r. Jmirnal of Pliys., 9, 1903) flnd that quinic acid does not cause any increase of uric acid eycretion in dogs. OF FOOD STUFFS 135 chide wliether the diminution was due to an increased destruction of the exogenous moiety (particularly the 50 per cent, which is ordinarily excreted as purin bodies), or to a decreased formation of endogenous purin from a depressant action of the drugs ; or whether it arose from an abnormal destruction of the endogenous purin moiety which generally escapes further cleavage. The entire question is exceedingly complicated and contains little promise of early solution. Certainly, the same experiments repeated with purin-free instead of a mixed diet, would serve for useful comparison, but in our present state of knowledge one fact stands out prominently, viz., that we have not a drug that can be administered in sufficient quantities to affect the circulation of urates in the tissues, and therefore that such medication is entirely useless. We are thiis, at present, in the condition of waiting for estimations of the endogenous uric acid output of a large number of healthy and diseased individiials. The figures which allow a considera- tion of the relation of leucocytosis, pyrexia and toxications to nuclein cleavage and excretion are comparatively few. We possess results which point to an excess of urate excretion in pneumonia, anaemia, cirrhoses of the liver, malignant tumours, and the acute stages of gout, but their appraisement is difficult, because of the conditions under which they were obtained. Until more reliable results exist, empiricism and fashion must direct the prophylactic treatment in metabolic disorders. Eecent researches have revealed much of the meta- 13G THE PURIX BODIES bolism of cats and dogs, but comparative studies can only point a guiding line to human investigations. If ii can be realised tbat the enormous difficulties of research upon the metabolic functions are being gradually surmounted, and that the study of the cleavage products of the several elements of proto- plasm is making rapid progress, it will be then understood that in the extension of our knoTrledge of the anomalies of body chemistry there are possibilities near ahead of enormous practical importance. It may be conceded that eacli individual has the capacity of very elastic adaptation, as, for instance, in the conditions of alkaptonuria, cystinuria, etc., but at the same time if the average action of the tissues is determined it may appear that in the majority of circumstances the adaptation follows certain fairly defined courses. It would seem that the hepatic functions are primarily concerned in gout and the metabolic dis- orders. During the intervals of the gouty attacks the uric acid excretion is apparently normal, although if any irritated or necrosing tissues exist, slow uratic infiltration is possible, but in the acute attacks there is a slight diminution before, and an excess during the attack. Here again must the question be put, is this increased formation or decreased destruction only? The consideration of these matters may therefore lead us to the acceptance of a thesis that uric acid is rather the symptom of, than the precise materies morbi in gout, and that its effect upon the tissues results rather from its combination with the products OF FOOD STUFFS 137 of abnormal metabolism tban from its excess in its usual compounds. If we abandon the former views and admit the value of uric acid estimations from the standpoint of symptomatology, we are a step nearer to the cause or number of causes which pro- duce the varied excretions. Thus the study of irregular, hereditary and acquired gout would prob- ably yield a series of uric acid variations quite distinct in character and quantities. Perhaps such results would direct attention to the associations of diet, habits or individual tendencies, and the relations of other metabolic disorders, such as diabetes and obesity. Until such time as we can obtain more figures for comparison and as a basis for further inA-estigation, in our ignorance of the exact causes of the toxic origin of the gouty diathesis, the only aveniie avail- able for actual treatment is the one so often advocated, viz., the maintenance of good digestive faculties, the diminution of intestinal fermentation and putrefaction by suitable remedies, the regular evacuation of the bowels, and the careful control of the circulatory system. The presence of un- known metabolites is very quickly reflected in the action of the heart and vessels — either through an effort of enforced elimination or by their direct effect on the vessel walls. When the excessive urate excretion betokens hepatic insufficiency the establishment of a correct circulatory uric acid com- bination and hepatic stimulation are indicated. And thus we arrive at the conclusion that those drugs, which stimulate the hepatic functions or 138 THE PURIN BODIES diminisli the variety and extent of abnormal products in the portal bloodstream, best assist the nuclein metabolism of the body and the normal expulsion of its cleavage products. Thus Luif finds that guaiacum is a useful prophylactic in gout, because it is a good hepatic stimulant. Hence the elimination of purin bodies cannot be directly influenced by drugs, although indirectly the excretion of uric acid may be altered, as, for instance, alkalies which stimulate diuresis and large quantities of liquids which demand early excretion, form media in which the purin bodies may be removed from the tissues. The maintenance of the liver functions should nevertheless command the first attention, and hepatic stimulants are the safest means of promoting purin excretion. If the liver is also assisted by the preservation of normal intestinal conditions and is so protected from the toxic products of proteid putrefaction or carbo- hydrate fermentation, then the circulation of purins in the bloodstream and their excretion through the kidney will be accelerated. The necessity for systematic estimations of the uric acid and purin excretion of individual patients becomes more important when we regard purin sub- stances as symptomatic. As each person presents variations in both exogenous and endogenous excre- tions, it will be apparent that for clinical purposes uric acid and purin estimations should be comparative as regards the same individual and not in relation to other patients. There are some drugs which appear to definitely hinder the elimination of purin bodies. Quinic OF FOOD STUFFS 139 acid and its compounds produce a diminished excre- tion of uric acid in some cases, but their action is slight as well as variable. Sodium salts, as Luff points out, lead to distinct delay, and almost to a retention of purin compounds, as uric acid readily forms insoluble combinations with sodium, and so uratic deposition is favoured. An interesting outlook in relation to this question is the action of some bodies which hinder or prevent the precipitation of uric acid andxanthin bodies from their solutions. Minkowski some time since remarked upon this property of nucleotin phosphoric acid, and has administered this substance to patients with the view of maintaining the circulating purins in solu- tion and preventing uratic iniiltration. At present, however, nucleotin phosphoric acid is not easily obtainable and very few results are recorded. 140 THE PURIN BODIES CHAPTER X. The Estimation of Uri^'ary Pueixs. Although uric acid may be considered more as one of the normal excretions tlian an extensive factor in the causation of disease, there are many conditions in which a knowledge of a patient's nuclein meta- bolism is of practical as well as of theoretical value. Eecent investigations have shown that a period of diminished uric acid excretion precedes acute attacks of gout, and if such alterations could be rapidly and easily observed, preventive measures might palliate if not avert the attack. The value of individual metabolic quotients has been already emphasised, and the possibility expressed that such information might lead to the earlier recognition of progressive changes in the chemical activities of the liver. This would at the same time indicate the possibility of any calculous deposits. Such evidence would also assist in the elucidation of the sources of endogenous ptirin, and of those conditions which excite or depress the synthesis and katabolism of nucleins. The estimation of uric acid is not difficult, but it requires considerable care and attention, a certain amount of apparatus and much more time than the clinical assistant or general practitioner is able to OF FOOD STUFFS 141 bestow. The reliable methods which may be used are as follows : — 1. Ludwig-Salkowski — precipitation and removal of phosphates — precipitation of total purins as silver- magnesium salt — decomposition by HaS or potassium sulphide — acidification and evaporation of the filtrate, crystallisation of the iiric acid — drying, weighing, or estimation of the N. by Kjeldahl's process. 2. Hofkins. Saturation of lOOcc. urine with SOgrms. NH4CI, after 1 — 2 hours, ppt., washed, acidified and heated to 90°C, evaporated to 30cc. and the uric acid crystallised, dried and weighed. Modifications : — Ritter, G. After solution of the ammonium urate, the addition of 20cc. strong H2SO4, and titration whilst warm against ^,'20 normal KMnOi. (1-578 KMnOJnl litre distilled H„0) lcc.= 00375gm. uric acid. Worner E. During precipitation the urine heated to 30 — 40° C, the ppt. washed with hot 10 per cent. (NH4)2 SO4 solution, the ammonium urate dissolved in 1 — 2 per cent. NaOH solution, and heated on a waterbath until all NH3 is driven off, and the N. of the evaporated solution then estimated by Kjeldahl's method. Lexoandotviky , M., first ascertains by titration the acidity of the urine, and then makes it nearly neutral. In acid urines the formation of the ammonium urate is slow and imperfect. Folin und Shaffer employ a solution containing oOOgm. (NH4)2 SO4, 5gm. uranium acetate, 60cc. 142 THE PURIX BODIES 10 per cent, acetic acid, 650cc. distilled water; 75cc. of this solution are added to 300cc. of urine, lOcc. NH4OH added, and the whole allowed to stand until the next day. The ppt. is washed with 10 per cent. (NH4)2 SO4 solution, then dissolved in lOOcc. HoO, 15cc. H2SO4 added, and the 115cc. titrated against KMnO^. Dimmock and Branson. lOOcc. of urine, warmed to 40°C., saturated with 31gms. NH4CI, shaken in a stoppered measuring glass and allowed to stand two to twelve hours. Precipitate washed with dilute ammonia (1 — 1000), and then placed in 25cc. solution of sodium hypobroniite in a generating bottle and the gas evolved measured in a graduated azotometer. The results are empirical but the error should not exceed three per cent. JoUes, A., after formation of the ammonium urate, removes the ammonia by heating with magnesia for 45 minutes, then adds lOcc. 1'4 per cent. H2SO4, and oxidises the uric acid to urea by KMn04. To the urea solution NaOH and bromine are added, and the N. evolved collected in an azotometer. All these methods are, however, too laborious for clinical use. As we have previously seen, both uric acid and the xanthin bases are the result of an un- destroyed or unoxidised portion of the total amount of purin bodies dealt with by the system. If food substances are taken that contain methyl-purins, only the xanthin portion of the urinary purins is increased, and if they are absent from the dietary the quantity of xanthin bases in the urine is very small. If no methyl xanthins are present, the total OF FOOD STUFFS 113 purin-N represents tlie purin end products of nuclein metabolism more fully than the uric acid alone. Hence, although the estimations of endogenous uric acid are valuable, much more so are those of the total urinary purins. If, then, some method for estimating the total purins were devised, which would occupy little time and yet give approximately accurate results, it would be of much practical use. The methods of Haycraft, Herman and Camerer for the estimation of the total alloxur bases offer no easier means to this end. The silver-magnesium precipitate is gelatinous in char- acter, falls only slowly, and takes many days to become firm enough to occupy a constant space. In a long glass tube of l|cm. diameter, a magnesium- silver precipitate from lOOcc. urine After 12 hours filled 27-5c.m. „ 36 „ „ 21-5 „ „ 6-t „ „ 20-5 „ A small quantity of magnesium silicate was then added, and in 12 hours the precipitate had fallen to 18'4cm., and there remained constant. With a graduated measure, a similar precipitate from 50cc. urine gave : — After 24 hours 21cc. ., 48 „ 20 „ Magnesium silicate was then added, and in 10 minutes the precipitate had sunk to 15cc. J 144 THE PUEIN BODIES The solution was next well shaken, and 15 minutes later the precipitate = 17cc. 24 hours „ „ „ = 20 „ at which point it hecanie constant. Many similar experiences yielded equal results; 001 uric acid was precipitated by Camerer's method and ^grm. talc added. 12 hours later the precipitate = 3.5 cc. 24 „ „ „ „ =33 48 „ , , , , , , — -J -J , , „ ., ., =32 „ 64 „ „ „ „ =31*., 88 „ „ „ „ =31 , 112 „ „ „ „ =30|„ 136 „ „ „ „ =30i, 178 „ „ „ ., =30 , 202 = 29J Oct. 18 0'Ol uric acid 24 hours after pi'ecipitation = 34 cc. ,, 20 0-01 ., 24 ,, ,, =34 ,. ,, 21 0-01 ., 24 „ ,, =34i .. It would thus appear that it is possible to obtain the silver-magnesium-purin precipitate as a firm, constant mass, as well as in gelatinous form. Should later experiments confirm this conclusion, it might be practicable to determine a specific value for each cc. of the precipitate, and so calculate from its amount the approximate quantity of purins present in the urine. But the reagent which serves as a medium to produce this result must itself occupy a constant space and be sufficiently fine and ponderous to overcome the varying densities of the solutions in OF FOOD STUFFS 145 which it acts. Talc appears to satisiy these two demands, and is without any reactive influence upon the other constituents. By the use of this medium I have obtained the following results : — 100 cc. of various urines Purin N" estimated by Camerer's method, (Kjeldahl N). •0299 •0287 •0258 •01.53 •0150 •0162 •0152 •0174 •0162 •0128 •0130 •0184 •0168 •0124 •0106 •0221 •0244 •0163 •0170 •0259 •0202 XOO cc, urine Silver — magnesium — purin- talc precipitate, 0- liO CO. 24 „ 23 „ 13 „ 13 „ 15 „ 15 „ 15|.. 15 „ 12 „ 12 „ 16 „ 14i„ 12 „ 11 „ 21 „ 23 „ 15 „ 16 „ 24 „ 18* „ From these figures it would appear that the pre- cipitate maintains a somewhat constant relation to 146 THE PURIN BODIES tlie amount of N. found by Kjeldahl's method, and gives a factor of O'OOll N. per cc. The table on page 147 states the results obtained by the use of this factor compared with those found by Camerer's method. Three separate estimations of lOOcc. urine were made at the same time. Compared with a similar estimation by Camerer's method, the con- stancy of the quantity of the silver-purin-talc precipitate confirms the previous figures. OF FOOD STUFFS 147 Table XXII. Amount OF Precipitate. Subjects of Measure Measure Measure Measure Calculated Cam- experiment. I. II. III. IV. N value erer N. Silver ppt. withour talc. Dr. K 24cc ...23CC....24 cc....28cc.. .0-0258. .0-0244 Prof. S 15 ,, ...15 „ ...15 ,,...22,, . .0-0165. .0-0163 „ S 15 „ ...16 ,,...15 ,, ... — . .0-0170. .0-0170 ■Vaktmiistare, J 24,, ...25 ,,...24 ,,...31 „. .0-0269. .0-0259 Patients from Serafimer lazarettet 1. Pleurisy 19 „ ...18 ,,...19 „...31„. .0-0203. .0-0202 2. Cardio-sclerosis ... 10 „ ...11 „ ...10 ,, ... — . .0-0115. .0-0116 3. Polyneuritis 13 „ ...13 ,,...13 ,, ... — . .0-0143. .0-0160 4. Acute nephritis ... i ,, ... 5 ,,... 4 ,, ... — . .0-0049. .0-0030 5. Chronic alcoholism 10 „ ...10 „ ...Hi ,, ... — . .0-0121. . — 6. Cardiac disease .... 4,, ...4i„ ... 4 „ ... — . .0-0046. .0-0033 For the opportunity to examine these pathological urines I am indebted to the Physicians of the Serafimer Lazarett, Stockholm. Expressed as total quantities of daily purin excre- tion, the results of the two methods sho-w close approximation : — Quantity of urine Measured ppt. N Camerer N In terms of uric acid and xanthin Dr. K .. lOOOcc. .. 0-2580 .. . 0-2440 .. 0-7320 Prof. S. . .. 1250,, .. 0-2062 .. . 0-2047 .. 0-6131 V. J .. 1200,, .. 0-3228 .. . 0-3108 .. 0-9324 Patient 1 . . . . .. 1150,, .. 1500,, .. 2000,, .. 1800,, .. 2000,, .. 1200,, .. 0-2340 .. .. 0-1725 .. .. 0-2860 .. .. 0-0680 .. .. 0-2420 .. .. 0-0430 .. . 0-2323 . 0-1730 . 0-3200 . 0-0540 . 0-0396 .. 0-6969 .. 0-5190 3 .. 0-9600 4 .. 0-1720 .. 0-7260 6 .. 0-1290 148 THE PURIN BODIES Althougli I cannot assume that tlie factor O'OOllN. per cc. of purin precipitate is absolutely correct, yet it will form a basis for the Avork of other observers, and lead, I hope, to the establishment of a definite factor. In the cases cited above, however, it gives very close results, and the figures agree most closely when the quantity of the urine approaches the normal. If the amount of urine and its specific gravity are markedly abnormal, the precipitate falls differently. The use of talc to a great extent over- comes this dif&cultj^; concentrated urines may be easily diluted, and dilute urines may be evaporated to any desired quantity in slightly acid solution. As Camerer's process involves the use of ammonia to fully dissolve the silver-chloride formed, the question as to the varying amounts of sodium chloride in pathological urines is important, for in order to obtain a near uniformity of density, the amount of fluid must not exceed a certain number of cc. Additionally, any excess of ammonia interferes with the proper precipitation of the purin bodies. As to the silver chloride, I have in many instances added 20 drops of concentrated HCl to 60cc. of urine, and experienced no difficulty with the solution of the chlorides in NH.iOIi. In a ease of chronic alcoholism, however, I was unable to entirely dissolve the silver chloride, and the part remaining fell with the purin precipitate, increasing its amount. A proposal to overcome this difficulty will be advanced later. Albuminous urines must be freed from albumin b}' boiling in slightly acidified solution. Medium amounts of sugar do not affect the precipitation, but OF FOOD STUFFS 149 with very large amounts, it is better to precipitate the urine with excess of copper sulphate and sodiumi bisulphite, decompose the precipitate by H2S or K2S, and then reprecipitate with ammoniacal silver nitrate solution. The method I have used is as follows: — After noting the total daily quantity, the urine is tested for albnmin. If present, this is removed by slight acidification with acetic acid and boiling. Two solu- tions are necessary : — No. 1 solution. Ludw:g's Magnesium Mixture 100 cc. Ammonia solution 20 X - 100 cc- Talc .. logrm. No. 2 solution Silver nitrate - - 1 grm. Ammonia (strong) - - 100 cc. Talc ... ; 5 grm. Distilled water - loo cc. To 90cc. of the urine, 20cc. of No. 1 solution are added. An immediate precipitate of the phosphates falls, and the clear fluid may be removed by filtration or decanted into another graduated measure glass. This precipitate should not be allowed to stand longer than 15 — 30 minutes, as otherwise the uric acid may be partially precipitated. To 80cc. of the filtrate 18cc. of solution No. 2 are added. The resultant precipitate is a mixture of silver-chloride and silver- purin ; the former body is dissolved by the excess of ammonia. The filtrate should be shaken until all white flakes disappear and the finely granular yellow- white precipitate remains suspended. If the AgCl is not entirely dissolved, strong ISrH40B[ is added drop by drop and the solution well shaken until no AgCl remains. The measure-glass is then corked and placed in a cupboard or corner protected from strong light. After an hour the purin precipitate will have 150 THE PUEIN BODIES entirely fallen, but it is best to wait 24 hours before reading the result. If tbe precipitate occupies Tec, then this amount multiplied by 1'5 and 0'0011 = percentage quantity of purin-N. = 0'0100 per ceiit., and multiplied by the total daily amount of uriae, say 1500cc. = 0'1500 N. or in terms of uric acid and xanthin bases = 0'45gm. Should it now be desired to estimate the precise total purin-N. by Kjeldahl's method, this may be easily performed after the pre- cipitate has been washed with water (60°C.) until the filtrate is neutral to lacmus paper, or the exact amount of uric acid may be estimated in the pre- cipitate by the Ludwig-Salkowski method. The process does not interfere with the details of the ordinary laboratory methods, but yields an approxi- mate result which for clinical purposes is sufficiently accurate, and allows the estimation to be attained at little cost of time and apparatus. Still, two measure- glasses are necessary, and the trouble of preparing filter paper, and the process of filtration occupy a certain amount of time. It would be of advantage, therefore, to have an apparatus in which the whole process could be completed easily. I think that the " purinometer " I now propose will meet this require- ment. It consists essentially of three parts : — 1. A closed, graduated tube. 2. A stop-cock, with a bore of the same diameter as the upper tube. 3. A small glass reservoir of known cubical capacity. It is used in the following manner : — With the stop at a right angle to the tube, urine is poured in OF FOOD STUFFS 101 up to 90cc. The stop-cock is then turned parallel with the tube, and the lower chamber and the bore of the tap become filled with the urine. ; 20 cc. of solution No. 1 is then added and the precipitate allowed to settle. If the reagent contains no talc, the precipitated phosphates take a long time to settle ; there is some loss of uric acid. To demonstrate the time saved by the addition of talc, an experiment may be cited. At 3-30 p.m. (Nov. 13), 60cc. urine, 7cc. Ludwig's magnesia mixture and 7cc. 20 per cent, ammonia solution were placed in two graduated measures. To one of these 5cc. of a 5 per cent, talc solution was added. p.m. With talc Precipitate Witliout talc 3'35 phosphate precipitate = 18 CC. ... phosphate precipitate = 72cc. 3-40 ,, „ =16 3-45 ,, ,. =14 3-50 „ ,, =13 3-55 ,, „ =1U = 70,, = 30 „ = 22 „ = 17 ,, The precipitate of phosphates sinks into the lower chamber of the purinometer, and immediately this has happened the tap is again turned at right angles. To the clear fluid now remaining in the iipper tube, solution No. 2 is added to make the total fluid lOOcc. The resultant precipitate consists of a mixture of silver-chloride and silver-purin. The apparatus is then inclined backwards and forwards until the pre- cipitate is yellowish-white. This can be readily seen by comparison with the white phosphate precipitate in the lower tube. The instrument is now allowed to stand 24 hours, when the percentage of purin may be read off at the upper level of the precipitate. Yaria- 152 THE PURIX BODIES tions in the quantities of phosphates can also be observed by a similar grading of the lower chamber. An advantage may be claimed in the case of an excess of chlorides, which solution IN'o. 2, or even a few added drops of strong ammonia will not dissolve. The silver-chloride is heavy and falls rapidly (within a minute), whilst the lighter pnrin precipitate takes an hour or so to settle. It is possible, therefore, to allow the silver-chloride to fall, turn the stop-cock, let the ppt. pass into the bore of the tap, and immedi- ately return the tap to a right angle. The loss of any purin-silver is by this means exceedingly light, and the silver-chloride excess does not interfere with the estimation. As the purinometer is graded in cc, it can be used for ordinary measuring purposes when occasion demands. The temperature of the room in which the estimations are made should be between 10°^15°C. The instru.ment is also of use for the collection and examination of urinary sediments for ptis, casts, crystals, etc. "When the insoluble substances have fallen, they can be passed into the lower chamber by slightly turning the stop-cock, and then, after emptying the upper chamber, be transferred to an object-glass, or if ttibercle bacilli are suspected, directly centrifugalised in an ordinary tube. In both cases work is facilitated. By use of the centrifuge, the precipitates became constant in a few minutes, and there was no necessity for the addition of talc. "Where such apparatus exists, the convenience of the method is increased OF FOOD STUFFS 153 and the results are more regular. A graduated centrifugalising tube is however necessary. Later experience shows that the results attained compare well with control estimations made by the Camerer process for total alloxuric bodies when the S.G. of the urine is between 1015 and 1025. With urines whose specific gravity is from 1000 — 1005, the percentages stated in the tables are too high, and for accurate estimations the urine must be evaporated in slightly acid solution to considerable concentration, although for clinical purposes the precipitates give relatively correct figures and allow useful comparison. The purinometer has been made for me by Gcetze, of Leipzig, and may be obtained from Messrs. Gallenkamp, Sun Street, Finsbuiy. 154 THE PURIN BODIES THE PURINOMETER OF FOOD STUFFS 155 CHAPTEE XI. Summary. Of the known purin-bodies, hypoxanthin, xantliin, guanin, and tlie niethyl-xanthins, caffeine and theo- bromin are found in foodstuffs, and uric acid, and traces of xantbins and metbyl-xantbins are met with in the urine. 1. As the methods available for the estimation of purin-bodies in animal organs were imsatisfactory, both as to technique and results, modifications were introduced and a reliable process worked out. 2. In foodstuffs, the purin-bodies occur in two forms, " free " and " hound." Both the glandular and muscular tissues contain approximately equal amounts of " /ree-purins," but the glandular tissues yield very large and the muscles only very small quantities of bound-purins (nucleins). 3. The estimations of the purin bodies contained in meats, show that considerable quantities are pre- sent, but that little difference exists between the amounts contained in white and dark meats. 4. Certain vegetable foods have been found to contain purin bodies. Amongst these are peas, beans, oatmeal, asparagus and onions. This furnishes a reason for the high uric acid excretion which follows their ingestion. 5. From several varieties of beer and porter purin- 156 THE PURIN BODIES bodies have been isolated, and their percentage amounts estimated. Their presence may account for the harmful influence of these beverages in gout, and for some of the pathological changes which occur in chronic alcoholism. 6. Experiments upon the action of the purin- bodies xipon carbohydrate metabolism show that caffeine induces an increased elimiination of CO2. Uric acid and hypoxanthin, however, are inert in this regard. 7. The continued daily injection of hypoxanthin into rabbits hinders their growth, causes degenerative cell changes in the liver and kidneys, alters the cellular relations and contents of the blood and marrow, and produces slight changes in the intima of the smaller blood-vessels. 8. Feeding experiments with fish, fowl, beef, haricot beans and beer, under appropriate conditions, show that the urinary purin is increased in all these cases ; that this increase corresponds with 50 to 60 per cent, of the purin-bodies ingested with the food ; that the purin is principally in the form of uric acid, and that the increase of urinary purin reflects the metabolic activity of the individual in regard to nucleins. 9. The faeces may contain unabsorbed nucleins as well as certain purin substances from, the digestive juices and cell-nuclei, and estimations of these bodies should be included in all metabolic experiments. 10. When the '' free " purins are ingested, they are rapidly oxidised and decomposed. About 50 — 60 per cent, of hypoxanthin leaves the body as urinary purin OF FOOD STUFFS 157 (principally uric acid) within 4 — 6 hours, and the same percentage of uric acid appears in the urine after 8 — 10 hours. The hound purins, however, take 1 — 2 days hefore they are fully excreted. 11. The remaining 50 per cent, of the food-purin is excreted as urea, or as bodies intermediate between uric acid and urea. 12. By the quantitative estimations of purin- bodies in foodstuffs, an exact forecast of the exogenous urinary purin is possible, and its amount can be limited when necessary by prescribing a certain diet. From the total urinary purin the exogenous portion can be deducted and the endogenous amount obtained. Tables iv., vii., and vii. should, therefore, not only be useful for dietetic purposes, but save a considerable amount of laboratory work. 13. The endogenous purin is partly derived from leucocytes, but mostly from the cell changes which resvilt in the maintenance of bodily functions. Hence, as the cell-nucleus is the dominating factor in metabolism, the cleavage of cell nucleins may incite the decomposition of proteid matter. It is possible that the endogenous urinary purin repre- sents about one-half of the total endogenous purin produced, and that the latter quantity indicates the extent of metabolic processes more completely than any other factors at present available. 14. Uric acid is a necessary result of normal nuclein metabolism. In disease it is symptomatic of conditions which hinder or prevent its solubility and excretion, and does not itself cause the lesions which accompany uricacid^mia. Drugs are unable to 158 THE PURIX BODIES increase its solubility in the bloodstream, but they may promote the normal processes of nuclein meta- bolism through hepatic stimulation. Uratic deposits take place slowly and their infiltration might perhaps be decreased by the administration of organic com- pounds which delay the precipitation of uric acid from its solution. 15. The general conclusions of the investigation point to the need for determinations of the endogenous purins in many diseases, either by the use of purin-free food, or by the aid of tables giving the percentages of purins in foodstuffs, and the necessary calculations therefrom. In order to assist the clinician in his attainment of such records, an instrument — the purinometer — is proposed, and the method for its use is described. 16. The action of the purin bodies upon the alimentary system, as demonstrated by Pawlow and later by Potapow-Procaitis, strongly contra-indicates the employment of meat extracts or soups in hyper- chloridia. OF FOOD STUFFS 1S9 LiTERATUEE. Ach, N. Tiber die diuretische Wirkung einiger purinderivate. " Arch. f. Exp. Path, und Pharm.," U, 1900. Albanese, 0. Ueber das Verhalten des Caffeins und des Theobromins im Organismus. " Arch. f. Exp. Path. und Pharm.," s. 449, 1895. Allen and Searle. The bromine method. " Analyst,'' p. 223, 1897. Anten, H. Action diuretique de la Caffeine et de la Theobromine. " Arch, de Pharm. et de Therap.," 1. 465, 1901. Archangelsky, W. Wirkung von Cafiee und von Thee auf Atmung und Herz. " Arch, de Pharm. et de Therap.," p. 425, 1900. Arnstein, J. Ueber die Bestimmung der Xanthin basen im Harn. " Zeit. fiir Physiolog. Chemie," s. 417, 1897; and " Centrbl. f. d. Med. Wissenchaft," 15, 1898. Armstrong. Red meat diet in certain cases of chronic gout. " Lancet," July 3, 1897. Ascoli, G. Ueber die stellung der Leber im Nuclein Stofiwechsel. " Pfliiger's Arohiv." Bd. 72, s. 340, 1898. Baginsky und Sommerfeld. Zur Kenntniss der Ausschei- dung von AUoxurkorper bei Erkrankungen des Kindlichen Alters. "Zeit. f. Physiolog. Chemie," s. 412, 1895. K 160 THE PURIN BODIES Baginsky, A. Ueber das Vorkommen von Xanthin und Hypo-xanthin. " Zeit. f. Physiolog. Chemie," s. 396, 1883. Bain, W. Action of drugs and diets in excretion of nitrogen in gout. " Brit. Med. Journal," April 7, 1900. Bang. Studien ueber die guanylsaure. " Zeit. f. Physiolog. Chemie," 31, p. 410, 1900; 32, p. 201, 1901. Bang und Raaschou. Darstellung der Guanylsaure. " Hofmeister's Beitrage.," Bd. 4, heft. 2, s. 175, 1903. Baldi, C. Azione della Xantina in rapporto piii special- mente con la excitabilite. " La Terapia Moderna," 12, 1891. Bauman and Bommer. Ueber die Fallung der Albu- mosen. " Zeit. f. Untersuch. d. Nahrungsmittel," s. 106, 1895. Bendix, B. Der Einfluss der Massage auf den Stoff- wechsel. "Zeit. f. Klin. Med." Bd. 25, s. 303, 1894. Bendix, B. Beitrage zum Stofiwechsel des Sauglings. " Jahrbuch f. Kinderheilkunde," s. 23, 1896. Bethe, A. Den Schuppen von Alburnus lucidus. " Zeit. f. Phys. Chemie," s. 472, 1895. Bier, A. Ueber die Ursachen der Herz-hyperthropie. " Munch. Med. Woch," 16, 1900. Binz, A. Die Wirkung des Destillats von Kaffee und Thee auf Atmung und Herz. " Centrbl. f. inn. Med.," 47, 1900. OF FOOD STUFFS 161 Blumenthal. Ueber die Aussclieidung der Harnsaure nach Dari'eichung von Chinasaure. " Charite Annalen." Bd. 25, s. 34, 1900. Bohland. Ueber den Einfluss des Salicylsauren Natrons auf die Bildung and Aussclieidung der Harnsaure. " Centrlbl. f. Inn. Med." Bd. 17, s. 70, 1896. Bohland. Ueber den Einfluss einiger Arzneimittel auf die Bildung und Ausscheidung der Harnsaure. " Miinch. Med. Woch." No. 16, s. 505, 1899. Borissow. Ueber des Vorkommen des Allantoins im Harn. " Zeit. f. Physiolog. Chemie." Bd. 19, p. 499, 1894. Bondzynski and Gottlieb. Ueber methyl-xanthin, ein Stoffweohsel product des Tbeobromin und Cafiein. " Arch. f. Exp. Path, und Pharm.," s. 132, 1895. Bouchard, Ch. Excretion de I'acide urique chez les Uricemiques. " C. R. de la Soo. Biol.," 1., 454, 1896. Bruce-Mitchell. Lettsomian Lectures, 1901. Brandenburg. Ueber die diagnostische Bedeutung der Harnsaure und Xanthin im Harn. " Berlin Klin. Woch.," s. 137, 1896. Bunge, G. Ueber die Physiologische Wirkung der Fleischbriihe. " Pfluger's Archiv.," s. 235, 1879. Burian und Schur. Der Darstellung von Purinkorper im Thierorganismus. " Zeit. f. Phys. Chemie.," s. 60, 1897. Burian und Schur. Der Darstellung von Purinkorper in der nienschlichen Stoffweohsel. " Archiv. f. d. ges. Phys.," s. 309, 1900. Burian und Schur. Der Darstellung von Purinkorper in der menschlichen Stoffwechsel. " Arch, f . d. ges. Phys.," s. 239, 1901. 162 THE PURIN BODIES Burian, R., and Walker Hall. Die Bestimmung der Purinstoffe in tierischenOrganen mittels derMethode des Korrigierten Wertes. " Zeit. f. Physiolog. Chemie.," Bd. 38, p. 336, 1903. Camerer, W. Zur Lehre von der Harnsaure und Gioht. " Deut. Med. Woch.," p. 356, 1891. Camerer, W. Harnsaure und Xanthinkorper im mensch.- lichen Earn. "Zeit. f. Biol., s. 78, 1891; "Zeit. f. Biol.," s. 218, 1897. Chittenden, C. H. The influence of alcohol on proteid metabolism. "Journal of Phys.," p. 220, 1891. Cohn, T. Beitrage zur Kenntniss des Stoffwechsels nach Thymus-nahrung. " Zeit. f. Physiolog. Chemie.," Bd. 35, p. 507, 1898. Corlette, A. Excretion in the small Intestine. " Journal of Phys.," p. 351, 1900. Croftan, A. " Medical Eecord," July 4, 1903 ; and " Pfliiger's Archiv.," 1903. Croftan, A. So-called Uric-acid lesions. "New York Med. Journal," August 11, 1900. Croftan, A. Role of alloxuric bases in Nephritis. "Journal of Amer. Med. Sci.," p. 592, 1900. Cushny and Van Naten. On the action of Caffeine on the Mammalian heart. " Archiv. f. Pharm.," Dec, 1901 ; " Journal of Phys.," p. 49, 1899. Dapper, Karl. Ueber Harnsaure-ausscheidung beim Menschen unter verschiedenen Ernahrungsverhalt- nissen. "Berlin Klin. Woch.," Bd. 30, p. 619, 1893. Demant, A. Zur Kenntniss der Extractive-stoffe der Muskels. " Zeit. f. Physiolog. Chemie.," s. 387, 1879. Determeyer und Buttner. Zer Therapie der Harnsauren Diathese. " Deutsoli. Med. Woch.," No. 21, 1901. OF FOOD STUFFS 163 Devoto, S. Eine neue Art der quantitative Eiweiss- bestimmung. " Zeit. f. Physiolog. Chemie., s. 465, 1891. Dickinson, W. " Allbutt's System of Medicine," p. 371, 1900. Dimmock and Branson. Determination of uric acid in urine. " Brit. Med. Journal," p. 585, Vol. 2, 1903. Drummond. Neurotic symptoms of Urio-acidoemia in the Young. "Lancet," Vol. i., p. 1,338, 1897. Duckworth, Sir Dyce. " Allbutt's System of Medicine," p. 407, 1899. Donogany and Tibald. Ueber den Einfluss des Alkohols im Organismus. " Ungar. Arch. f. Med.,'' s. 189, 1895. Dominici, M. Sur le plan de structure du systeme hematopoietique des mammiferes. " Arch, de Med. Exp. et d'anat. Path.," p. 473, 1901. Douglas, C. Observations upon the excretion of uric acid. "Edin. Med. Journal," p. 32, 1900. Dreschel and Balke. Zur Kenntniss von Xanthinkorper. " Dissert.," 1889. Dunin und Nowaczek. Harnsaure-ausscheidung bei croupouser pneumonie. " Zeit. f. klin. Med.," s. 1, 1897. Ebstein. Vererbbare Cellulare Stofiwechselkrankheiten, Stuttgart, 1902. Ebstein und Nicolaier. "Die Ausscheidung der Harnsaure durch Nieren." Virchow's Archiv., Bd. 143, 1896. Fere, Ch. Note sur I'influence du cafe sur le travail. " C. R. de la Soc. Biol.," p. 627, 1901. Filehne, W. Ueber einige Wirkungen des Xanthins. "Arch. f. Anat. und Phys.," s. 72, 1886. 164 THE PURIN BODIES Fischer, Emil. Syntliesen in der Puringruppe. " Ber d. Deutsche Chemischen Gesellschaft.," s. 435, Bd. 32, 1899. Numerous earlier papers. Fischer, Emil. Synthesen in der Purin und Zucker- gruppe. " Braunschweig,'' 1903. Lecture given at Nobel prize distribution. Folin and Schaffer. Ueber die quantitative Bestimmung der Harnsaure im Harn. " Zeit. f. Physiolog. Chemie.," s. 56, 1901. Forster. Die Beeinflussung der Harnsaure-ausscheidung mit specieller Beriicksichtigung der Chinasaure und der Chinasauren Salze. " Inaug. Diss. Breslau., 1899. Formanek. Ueber den Einfluss kalter Bader auf die Harnsaure Ausscheidung beim Menschen. " Zeit. f. Physiolog. Chemie.," Bd. 19, s. 271, 1891. Fiirth, v. Ueber die Eiweiss-Korper des Muskel-plasmus. " Arch. f. Exp. Path, und Pharm.," s. 231, 1895. Gamgee, Arthur, and Jones, Walter. Ueber die Nukleo- proteid des Pankreas, der Thymus und der Neben- niere mit besonderer Beriicksichtigung ilirer optisohen Aktivitat. " Hofmeister's Beitrage Zur Chem. Pliys. und Path.," iv., p. 10, 1903. Gar rod, A. Treatise on Gout, 1883, and " A new view of the formation of uric acid." Proc. Roy. Soc, 1893. Gaucher, A. Pathogenesis der nephrite. These de Paris, 1886. " Revue de Med.," L 367, 1886. Gautier, A. Les Toxines, 1. 264, 1896. Giacosa. Ueber die Bildung der Harnsaure im Organismus. " Maly's Jaliresbericht," Bd. 21, s. 182, 1891. OF FOOD STUFFS 165 Goeppert, F. Ueber Harnsaure-aussclieidung. " JahrbuCh f. Kinderheilkunde," Bd. 51, s. 334, 1900. Goodbury, W. The action of Lysidin and Piperazin as Uric Acid Solvent. " Brit. Med. Journ.," October 3, 1896. Goto, M. Ueber die Losing der Harnsaure durch Nucleinsaure und Tliymusaure. "Zeit. f. Physiolog. Chemie.," Bd. 30, s. 473, 1900. Gottlieb und Magnus. Ueber die Beziehungen der Nieren circulation zur diuresis. " Arch f. Exp. Path, und Pharm.," s. 223, 1900. Green, A. Vegetable Physiology, p. 274, 1900. Hammond, C. The physiological effects of Alcohol. " Amer. Journal of Med. Sci.," p. 305, 1856. Hammarsten. " Physiologiska Chemie.," 1898; also English translation, 1902. Haig, A. Uric acid as a factor in the causation of disease, 1900—1903. Haig, A. The bo'dy as an analytical laboratory. " Brit. Med. Journal," p. 1078, 1901. Harley, Geo. Gout in relation to liver disease. " Lancet," September 4, 1896. Hedbom, K. Ueber die Einwirkung verschiedener Stofie auf das isolirte Saugethierherz. " Skand. Arch. f. Phys.," s. 165, 1895. Heerlein, W. Das Caffein und das Kaffee destillat in ihrer Beziehung zum Stofiwechsel. " Pfliiiger's Archiv.," p. 165, 1892. Herland. Untersuchungen ueber die Nucleinsaure. " Arch. f. Exp. Path, und Pharm." Bd. 44, 1900. 166 THE PURIN BODIES Herman, H. Harnsaure-ausschiedung von Nahrungs- mitteln mit Rucksioht auf die Gicht. " Deut. Archiv. f. Klin. Med.," s. 279, 1888. Herringham and Davies. On the secretion of uric acid and urea. "Journal of Physiology," vol. 12, p. 475, 1891. Herter and Smith. The excretion of uric acid in health and disease. " New York Med. Journal," 1892. Hess und Schmoll. Ueber die Beziehungen der Eiweiss substanzen der Nahrung zur Alloxurkorper ausschei- dung. " Arch. f. Exp. Path, und Pharm.," s. 24, 1896. His, W. Untersuchungen an Gichtkranken. " Berlin Klin. Wooh.," s. 970, 1896. His und Hagen. Kritische Untersuchungen ueber der Nachweis von Purin basen. " Zeit. f. Physiolog. Chemie.," s. 351, 1900. His, W. (jun.). Das Verhalten der Harnsaure im Thierischen Organismus. " Verhand. des 17 Cong, f. inn. Med.," s. 315, 1899. His, W. (jun.). Physikalische Chemische Untersuchungen ueber das Verhalten der Harnsaure und ihrer Salze in Losungen. " Verhand. des 18 Cong. f. inn. Med.," s. 425, 1900. Hopkins and Hope. On the relation of uric acid excretions to diet. " Journal of Physiolog.," p. 271, 1898. Hoppe-Seyler, F. Apparat zur Messung der respirato- rischen Aufnahme im Menschen. " Zeit f. Physiolog. Chemie.," s. 579, 1894. OF FOOD STUFFS 167 Horbaozewski. Beitrage zur Kenntniss der Bildung der Harnsaure und des Xanthin basen. " Sitzuns- bericht der k. Acad. d. Wiss. Wien," 1891. Hutchison, R. Food and the principles of dietetics," p. 63, 1900. Hutchison and Macleod. Alloxuric excretion in a case of Leucopenia. " Amer. Journal of Exp. Med.," p. 541, 1901. Huber und Lichtenstein. Ueber Gioht und ihre Behandlung mit Chinasaiire. " Berlin. Klin. Woch.'' No. 28, 1902. Iwanoff, L. Fermentative Zersetzung der Thymonuklein- saure durch Schimmelpilze. " Zeit. f . Phys. Chemie.," No. 39, s. 31, 1903. von Jaksch. Ueber Uricacidsemia. " Deut. Med. Woch," s. 741, 1890. Jerome, W. J. S. The formation of uric acid in man, and the influence of diet on its daily output. "Journal of Physiology," p. 124, 1898. Jerome, W. J. S. Uric acid after certain foods. "Journal of Physiology," p. 98, 1899. Jolles, A. Ueber eine neue methode zur quantitativen Bestimmung der Harnsaure im Harn. " Zeit. f. Physiolog. Chemie.," s. 223, 1901. Jolles, A. Beitrage zur Kenntniss der Purinbaseu. "Journal f. Praktische Chemie." Bd. 12, s. 61, 1900. Kaufman und Molir. Beitrage zur Alloxurkorperfrage und zur Pathologic der Gicht. " Deutsche Archiv. f. Klin. Med," 1902. Bd. 74, s. 141, 348, 586. Katz, J. Die mineralischen Bestandtheile des Muskel- fleisches. " Pfliiger's Archiv.,'' s. 63, bd. 85. 168 THE PURIN BODIES Keiiunerich, G. Untersucliung ueber die pliysiologisolie Wirkung des Fleisohextracts. " Pfliigers Arcliiv.,'' s. 49, 1869. Klemperer, A. Ueber die Wirkung des CafEeins auf die Muskeln. " Untersuchungen ueber Gicht," 1896. Klemperer, G. 1st Fischkost rathsamer als Fleisch bei Harnsaure Diathesis. " Therapie. der Gegenwart." Bd. 3, s. 428. 1901. Kochmann, M. Ueber Fleisclmahrung und ilire Beziebungen zur Gicht. " Archiv. f. die Ges. Physiolog." Bd. 94, s. 593, 1903. Kolisch und Tandler. Monograph, 1895. Kolisch und Dostal. Das verbalten der Alloxurkorper im pathologischer Harn. " Wien. Klin. Wooh," 1895. Kobert, W. Ueber den Einfluss verschiedener pharmo- kologischer Agentier auf die Muskel substanz. "Arch. f. Exp. Path, und Pharm," 15, 1882. Kossel, A. Ueber Xanthin und Hypoxanthin. " Zeit. f. Physiolog. Cheniie.," s. 428, 1881. Kossel, A. Beitrage zur Chemie des Zellkerns. '' Zeit. f. Physiolog. Chemie," s. 248, 1884. Kossel, A. Zur Chemie des Zellkerns. " Zeit. f. Physiolog. Chemie.," s. 7, 1882. Kossel, A. Ueber Guanin and Beitrage zur Chemie des Zellkerns. " Zeit. f . Physiolog. Chemie," s. 404, 1883. Kossel und Neumann. Ueber die Spaltungsproducte der Nucleinsaure. " Sitz. d. Kong. Prusslich Akad. der Wissenschaften." Bd. 18, 1894. OF FOOD STUFFS 169 Kossel und Neumann. Ueber Nucleinsaure und Thymin- saure. "Zeit. f. Physiolog. Chemie." Bd. 22, e. 74, 1896. Kossel und Steudel. Weitere Untersuchungen iiber das Cytosin. "Zeit. f. Physiolog. Chemie." Bd. 38, s. 49, 1903. Kriiger, M. Zur Kenntniss des Adenins und Hypoxanthin. " Zeit. f. Physiolog. Chemie.," s. 444, 1894. Kriiger und Wulfi. Ueber eine methode zur Bestimmung der Xanthinkorper im Harn. " Zeit. f. Physiolog. Chemie.," 20, s. 176, 1896. Kriiger und Schmidt. Ueber das Verhalten von Theo- bromin im Organismus. " Ber. der. deut. Cliem. Gesell.," p. 2,677, 3,336, 32; and "Zeit. f. Physiolog. Chemie." Bd. 34, p. 549, 1902. Kriiger und Schmidt. Die Purinkorper der Menschlichen Fseces. "Zeit. f. Physiolog. Chemie." Bd. 35, s. 153, 1902. Laquer, S. Ausscheidungs-verhaltnisse der Alloxur- korper im Harn. " Verh. f. d. Kong. inn. Med.," 1896. Laquer, B. Ueber Beeinflussung der Alloxurk5rper- ausscheidung durch Milchdiat und iiber Fettmilch bei Gicht. " Berlin klin. Woch.," iv., 36, 1896. Latham, W. P. Croonian Lectures. 1886. Laquer, W. Einfluss der Emser Quellen auf die Harn- saure. "Berliner Klin. Woch., No. 26, 1903. Laval. De I'influence des Exercise Physiques sur I'excretion de I'acid unique. " Revue de Med.," 16, p. 384, 1896. 170 THE PTJRIN BODIES Lebers, H. Zur Pathologie der Harnsaure beim Mensclien. "Berliner Klin. Woch.," No. U, 1897. Leblond, A. Etude de la Cafeine. Paris, 1883. Lehman und Wilhelm. Besitz das Caffein und die Caffein- f reien Kaffee-surrogate eine Cafieeartige Wirkung 1 "Archiv. f. Hygiene," s. 310, 1898. Lehmann, K. Ueber die Wirkung des Fleisch extracts. "Arcliiv. f. Hygiene," s. 249, 1885. Lewandowsky, M. Ueber die Wornersche Methode der Harnsaure-bestimmung. " Zeit. f. Klin. Med.," s. 199, 1900. Lewandowski. Versuche liber den Einfluss der Benzoe- saure auf die Harnsaure-bildung. " Zeit. f. Klin. Med." Bd. 40, s. 202, 1900. Levene, P. A. Darstellung und Analyse einiger Nuclein- sauren. "Zeit. f. Physiolog. Chemie." Bd. 38, 1903 (other papers in " Amer. Journ. of Physiology " ). Levy, M. Beitrage zum Stoffwechsel bei Gicht. " Berlin Klin. Woch.," s. 387, 1896. Leyden, V. Ernahrungs-therapie und Diatetik., s. 364, 1897. Loewi, 0. Untersuchung ueber den Nuclein Stoffwechsel. ' Arch. f. Exp. Path, und Pharm.," s. 159, 1901. Loewy, J. Der Eiweiss Stoffwechsel in einem Falle von Antemia Splenica. " Cbl. f. inn. Med.," s. 983, 1897. Luff, A. P. Chemistry and Pathology of Gout. Goul- stonian Lectures, 1897. Luff, A. P. Value of certain drugs in the treatment of Gout. "Lancet," p. 1,606, June 11, 1898. Luff, Arthur P. Gout, its Pathology and Treatment. 1898. OF FOOD STUFFS 171 Lusini, V. L'action biologique et toxique des Xanthins. " Archiv. Ital. de Biol.," p. 212, 1900. Llithje, S. Der Einfluss der Blei auf die Harnsaure- ausscheidung." Zeit. f. Klin. Med.," s. 266, 1896. Luzzatto, A. M. Uber das Verhalten des Allantoins im Tierkorper. " Zeit. f. Pliysiolog. Chemie." Bd. 38, 1903. V. Mach. Ueber die Bildung der Harnsaure aus dem Hypoxanthin. " Arch. f. Exp. Path, und Pharm." Bd. 24, s. 389. Malf atti. Ueber die Kriiger-WulfE's Reaction. " Wien. Klin. Woch.," s. 597, 1900. Malfatti. Ueber die Alloxur-korper und ihr Verhaltniss zur Gicht. " Wiener Klin. Woch.," s. 723, 1896. Mares. Sur I'origine de I'acide urique chez rhomme. "Archives SJaves de Biol.," p. 207, 1888. Mark-Schnorf, F. Zur Physiologie der Verdauung. " Pfliiger's Archiv.," s. 143, 1901. Martin, C Ueber die Aussoheidungs-verhaltniss der Alloxur-korper bei Nephritis. " Centrlb. f. inn. Med." Bd. 20, s. 625, 1899. Maurel, E. Influence des variations des Azotes de L'alimentation sur L'excretion de L'acide-urique. " C. R. de la See. de Biol.," p. 427, 1901. Mayer, P. Ueber den Einfluss nuclein-haltiger Nahrung auf die Harnsaure-bildung. " Deut. Med Woch.," s. 186, 1896. Mendel, Underbill and White. Physiological Studies in Nucleic Acid. " American Journal of Physiology." Vol. viii.. No. 5, p. 377, 1903 — which contains refer- ences to numerous earlier works. 172 THE PURIN BODIES Meisoher, 0. Pliysiologischechemische Untersucliungen ueber die Lachsmilch. " Arch. f. Exp. Path.," 36, s. Ill, 1896. Milroy and Malcolm. The Metabolism of nucleins. " Journal of Pliys.," p. 106, 1899. Milroy, T. H. The formation of uric acid in birds. " Journal of Physiology," 30, p. 47, 1903. Minkowski, O. Untersuchungen zur physiologie und pathologie der Harnsaure bei Saugethieren. " Arch. f. Exp. Path.," s. 375, 1898. Minkowski, 0. Ueber die Unwandlung der Purin-korper im Organismus. " Deutsche. Med. Woch. No. 28, 1902. Minkowski, 0. Die Gicht. " Wien," 1903. Mochizueki. " Archiv. f. Verdauungskrankheiten," 7, p. 221, 1901. Moscatelli, R. Ueber den Zucker und Allantoin im Harn. " Zeit. f. Physiolog. Chemie.," p. 203, 1889. Miinzer, E. Der Stoffwechsel des Menschen bei acutev Phosphorvergiftung. "Deut. Archiv. f. Klin. Med.," p. 236, 52. Neubauer. " Zeit. f. Analy. Chem.," s. 33, 1867. Neumayer, S. " Verhand. f. d. Cong. inn. Med.," s. 421:, 1896. Nicolaier. Ueber die Umwandlung des Adenin im thierischen Organismus. " Deutsche Med. Woch.'' No. 14, 1902, and "Zeit. fiir. Klin. Med," 45, p. 35p, 1902. Von Noorden. " Verhand f. Cong. inn. Med," s. 424, 1896. Von Noorden. Lehrbuch, Stoffwechsel, 1894. ■Oliver. Lead poisoning. Goulstonian Lectures, 1891. OF FOOD STUFFS 173 Offer and Rosenqvist. Ueber die weissen und dunklen Fleisches. "Berlin. Klin. Wooh," ii, 45, 1899. Parker, W. Xanthines in the Faeces. " Amer. Journal of Phys.," s. 37, 1901. Parisot, A. Etude de Taction de la cafEeine sur les functions motrices, Paris, 1890. Pawlow, M. Die Arbeit der Verdauungs-drusen, Wies- baden, 1898. Petren, K. Ueber das Vorkommen der Xanthin basen in den Faeces. " Skand. Arch. f. Phys.,'' s. 315, 1898. Petren, K. Nachtrag. "Skand. Arch. f. Phys," s. 412, 1899. Petren, K. Nachtrag. "Arch. f. Exp. Path.," s. 269, 1900. Petren, K. Ueber das Vorkommen von Harnaaure im Blute bei Menschen. " Arch, f . Exp. Path, and Pharm.," 41, s. 265, 1898. Pfeiffer. Ueber Harnsaure Verbindungen beim Menschen. " Berlin. Klin. Woch.," s. 913, 1894. Poduschka. Versuche ueber Allantoin Ausscheidung. "Arch. f. Exp. Path, and Pharm.," 44, s. 59, 1899. Pohl. Ueber Allantoin bei Intoxikationen. '' Arch. f. Exp. Path." Bd. 48, s. 367. Pope. Kenntniss der Beziehungen zwischen Hyperleuko- cyten und Alloxurkorperausscheidung. " Centrlb. f. inn. Med.," s. 657, 1899. Potapow-Procaitis, M. Influence de quelques alimento sur la quantite et la qualite de sue gastrique. " These," Lausanne, 1901. Reach, F. Beitrage zur Kenntniss des Stoffwechsel bei der Gicht. " Miinch. Med. Woch.," s. 1,215, 1902. 174 THE PUEIN BODIES Richter, Paul (jun.). " Zeit. Klin. Med.," 27, p. 311, 1895; "Charite Annalen," Bd. 25, s. 197, 1900. Reiss, J. Ueber den Einfluss des Alkohol auf den Stofi- wechsel. "Zeit. f. Klin. Med.," s. 1, 1881. Ritter, G. von. Ueber die Bestimmung der Harnsaure. "Zeit. f. Phys. Cliemie.," 21, s. 288, 1896. Roberts, Sir W. Chemistry and Therapeutics of Uric Acid, 1892. Rommel, 0. Die Ausscheidung der Alloxurkorper bei Giclit. "Zeit. f. Klin. Med.," s. 200, 1900." Rest, J. Ueber die Ausscheidung des Cafiein im Harn. "Arch. f. Exp. Path., s. 71, 1895. Roseman. Ueber den Einfluss des Alkobols auf die Harnsaure Ausscheidumg. " Deutsche Med. Woch.," No. 32, 1901. Rosenfeld, G. Harnsaure und Diat. "Allgemeine Med. Central. Zeitung," s. 789, 1896. Salomon, G. Ueber die Verbreituns; und Enstehuns: von Hypoxanthin und Milohsaure im Thierisohen Organism. "Zeit. fiir Phys. Chemie.," s. 65, 1878. Salomon, G. Ueber die Verbreitung von Hypoxanthin im Thierischen Organism. " Zeit. fiir Physiolog. Chemie.," 2, 5, 65, 1879. Santesson, G. Wirkung des Cafieins auf das Herz des Kaninschen. " Skand. Archiv. f. Phys.," 12, 1902. Saundby, A. Lectures on Renal Diseases, p. 170, 1896. Salkowski. Ueber das Vorkommen von Allantoin im Harn nach Fiitterung mit Pancreas. " Centrlb. f. Med. Wissenchaft," s. 929, 1898. Salkowski. Ueber das Verhalten der in den Magen Eingefiihrten Harnsaure im Organismus. '' Zeit. f. Physiolog. Chemie.," 35, s. 495, 1902. OF FOOD STUFFS 175 Salomon und Kriiger. Die AUoxurbasen des Harns und ihre Physiologisclier Bedeutung. " Deut. Med. Woch.," 25, s. 97, 1899. Schafer, E. A. Handbook of Physiology, vol. i., p. 719, 1898. Scherk. 1st die Fleischkost bei Gichtkranken indioiert ? "Zeit. f. Krankenpflege," p. 29, 1897. Schmidt, R. Ueber Alloxurkorper in ihrer Beziehung zu pathologische CEnderungen im Zell-leben. " Zeit. f. Klin. Med.," 34. Schmidt-Nielson. Zur Kenntniss der Autolyses des Fischfleisches. " Hofmeister's Beitrage," Bd. 3, p. 266—275. Schindler. Beitrage zur Kenntniss des Adenins, Guanins und ihrer derivate. " Zeit. f. Physiolog. Chemie.," s. 439, 1887. Schmiedeberg, 0. Vergleichende Untersuchungen ueber die pharmakologischen Wirkungen einiger Purin. " Berichte der Deutsche Chem. Gessellschaft.," p. 2550, 1901. Schondorfi. Die Stellung der Purin-korper im Mensch- lichen Stofiwechsel. " Pfiuger's Arch.," 81, 1900. Schreiber, E. Ueber die Harnsaiire. Monograph. Stuttgart, 1899. Schreiber und Waldvogel. Beitrage zur Kenntniss der Harnsaure-aussoheidung. " Arch. f. Exp. Path, und Pharm.," s. 74, 1895. Schreiber, E. " Deutsch. Med. Woch.," s. 41, 1897. Schultze und Bossard. Zur Kenntniss des Vorkommen von Allantoin, Asparagin, Hypoxanthin und Guanin in der Planzen. " Zeit. f. Physiolog. Chemie.," 9, s. 420, 1885. 176 THE PURIN BODIES Scliultze und Bossard. IJeber das Vorkommen von Verniii. " Zeit. f. Physiolog. Cliemie.," 10, s. 326, 1886. Senator. " Notlinagel's Handbuch," 19, p. 231, 1898. Senator. Ueber die Unterscheidung des Weissen und des dunklen Fleisclies. " Berlin. Klin. Wocli." No. 4.5, 1899. Siven, 0. Zur Kenntniss Harnsaure-bildung in Mensch- lischen Organen unter physiologische Verhaltniss. "Skand. Arcli. f. Phys.," x., 1900. Smith, E. Experiments upon the action of food upon the respiration. Proc. Eoy. See, 1859. " Lancet,'' p. 215, 1859. Sa^tbeer und Ibrahim. Ueber das Schicksal eingefiihrter Harnsaure im Menschliche Organismus. " Zeit. f. Physiolog. Chemie.," 35, s. 1, 1902. Sonden ooh Tigerstedt. " Skand. Arch. f. Phys." Bd. vi., 1894. Spitzer, W. Die Ueberfulirung von Nucleinbasen im Harnsaure durch die Sauerstoffe iiber tragende Wirkung von Gewebsauszuge. " Pfliiger's Archiv.," 76, s. 191, 1899. Stadeler. " Liebig's Aiinalen." Bd. 116, s. 105, 1860. Steudel, H. Die constitution des Thymins. " Zeit. f. Physiolog. Chemie.," s. 241, 1901. Steudel, H. Das Verhalten einiger pyrimidin derivate im Organismus. " Zeit. f. Physiolog. Chemie.," s. 255, 1901. Strecker. " Liebig's Annalen," s. 137, 1858. Strauss. Ueber die Beeinflussung der Harnsaure und Alloxurbasen ausscheidung durch die Estractivestofie des Fleischen. "Berlin Klin. Woch.," s. 710, 1896^ and "Zeit. f. Klin. Med.," s. 319, 1896. OF FOOD STUFFS 177 Sundvik, E. Xantliinstofie aus Harnsaure. " Zeit. f. Physiolog. Chemie.," s. 131, 1898. Swain, R. E. The formation of Allantoin from uric acid in tlie animal body. " Amer. Journ. of Phys.," p. 38, 1901. Taylor, E. The influence of various diets upon the elimination of uric acid and the purin bases. " Amer. Journal of Medical Sciences," p. 141, 1899. Taylor, A. E. Beitrage zur Verwerthung der Kriiger- AVulfisches method zur Bestimmung der Alloxur- korper im Earn. " Cbl. f. inn. Med., s. 873, 1897. Tunnicliffe and Rosenheim. Contribution to our know-" ledge of uric acid salts. " Lancet," p. 1708, 1900. Ulrici, H. Ueber pharmakologische Beeinflussung der Harnsaure-aussoheidung. " Arch. f. Exp. Path., ' s. 321, 1901. Umber, A. Ueber den Einfluss nucleinhaltiger Nahrung auf die Harnsaure-bildung. " Zeit. f. Klin Med.," s. 174, 1896. Vinci, L. Azione della Caffeina sulla pressione sanguine." " Arch, di Farmacolog. et Therap.," 365, 1891. Vogt, H. Ein StofEwechselversuch bei Acuter Gicht. "Deutsch Archiv. f. Klin. Med." Bd. 71, s. 21, 1901. Walker Hall. The relation of purin bodies to certain metabolic disorders. " Brit. Med. Journal," June 14th, 1902. Walker Hall. The elimination of CO^ in certain meta- bolic disorders. " Journal of Pathology," p. 282, 1903. 17S THE PURIN BODIES Walker Hall. Zur klinischen Bestimmung des Gesamt- gehaltes von Purin in Harn mittels Purinometer. " Wiener Klinischen Woohenschrift. No. 14, 1903. Walker Hall. Determination approximative des purines urinaires par le Purinomfetre. " Archives Gen. de Medecine," p. 597, 1902. Walker Hall. The action of continued injection of hypo- xanthin upon the tissues of rabbits. " Virohow's Arohiv." Bd. 174, 1903. Walker Hall. Metabolism in Gout. " The Practitioner " (special gout number), July, 1903. Walker Hall. The purin bodies of human feeces in health and disease. " Brit. Med. Journal," p. 582, Vol. 2, 1903. AValker Hall. Vegetabilische Nahrung und Getranke bei Gicht und Nephritis. " Berlin. Klin. Wooh.," No. 38, 1903. Walker Hall and Burian, R. Die Bestimmung des Purin- stofie. " Zeit. f. Physiolog. Chemie." Bd. 38, p. 336, 1903. Watson, Chalmers. Metabolism in Gout. " Edin. Med. Journal," p. 103, 1900. Watson, Chalmers. Observations on general metabolism in Gout. "Brit. Med. Journ.," Jan. 6, 1900. Watson, Chalmers. The action of salicylate of soda and nucleic acid upon the general metabolism in Gout. " Journal of Pathology," p. 103, 1900. Watson, Chalmers. Gout article, in " Encylopedia Medioa." Vol. iv., 1901. Weintraud, W. Ueber die Ausscheidung von Harnsaure und Xanthinbasen durch die Faces. " Centrlb. f. inn. Med.," s. 18, 189.5. OF FOOD STUFFS 179 Weintraud, W. Beitrage zur Stoffwechsel der Gicht. " Charite Annalen," s. 275, 1895. Weintraud, W. Ueber Harnsaure im Blut und ilire Bedeutung fur die Ensteliung der Gicht. " Wien. Klin. Rundschau," g. 8, 1896. Weintraud, W. Enstehung der Harnsaure im Sauge- thier-organismus. " Verhand. f. d. Cong, f . inn. Med.," s. 190, 1896. Weintraud, W. Ueber den Abbau des Nuoleins im Stofiwechsel. " Verhandlungen des 18 Cong. f. inn. Med.," 1900. Weiss, J. Beitrage zur Erforschung der Bedingungen der Harnsaure-bildung. "Zeit. f. Physiolog. Chemie." Bd. 27, s. 216, 1899. Weiss, J. Ueber den Einfluss von Alkohol und Obst auf die Harnsaure-bildung. " Miinch. Med. Woch.," s. 1048, 1901. West, S. Granular Kidney and Physiological Albumin- uria, p. 154, 1900. Wheeler and Merriam. Syntliesis of Uracil, Thymin, and similar combinations. " Amer. Cliem. Journ.," Vol. xxix., s. 478, 1903. Wheeler und Johnson. Cytosin or 2 oxy-six-amino- pyrimidin. " Amer. Chem. Journal," Vol. xxix., s. 505, 1903. Wohler und Frerichs. "Annalen der Chemie und Pharm." Bd. 65, s. 340, 1848; and Bd. 26, s. 241, 1838. Wiener, H. Zersetzung und Bildung der Harnsaure im Thierkorper. " Arch. Exp. Path.," 42, s. 374, 1899. Wiener, H. Ueber Synthetische Bildung von Harnsaure im Thierkorper. "Hofmeister's Beitrage Zur Chem. Physiologie und Pathologie," s. 42, 1902. 180 THE PUEIN BODIES Worner, E. Eiii einfachen Verfaliren zur Bestimmung der Harnsaure. " Zeit. f. Pliysiolog. Chemie.," 27, s. 70, 1900. Yeo, B. Food in health and disease. 1897. Zuelzer, G. Ueber die Alloxur-korper ausscheidung im Harn bei nephritis. "Berlin. Klin. Wocli.," s. 72. 1896. Zuntz, 0. Die Absoheidung der peptisolien Yerdauungs- produkte mittelst Zinksulfat. " Zeit. f. Pliysiolog. Chemie.," 27, s. 219, 1899. Zerner, E. Cheniischen Bedingungen fur die Bildung von Harnsaure-sedinienten. " Wieu. Klin. Woch.," s. 272, 1893. OF FOOD STUFFS 181 APPENDIX. Constitution and Calorific Values of certain Foodstuffs. Water Proteid Fish : Cod 76.1 23. Plaice 77.9 18.7 Salmon 76. 15. Halibut 75.2 19.9 Meat : Beef 72. 21. Fat 54. 16. Mutton 76. 18. Fat 48. 15. Veal 76. 20. Fat 72. 18. Pork 72. 19. Fat 47. 14. Ham 41. 23. Meat Soups — 8. Chicken 76. 19.5 Vegetables : Potatoes 74. 2. Eice 10. 6.7 Flour, white .... 16.5 13. Bread, white ... 40. 7. Oatmeal 15. 13. Peas 14.3 21.1 Lentils 12.5 24.8 Beans (Haricot) 14.8 25.1 Asparagus 93.3 1.9 Cabbage 80.0 3.9 Lettuce 94.3 1.4 Fat Carbo- hydrates Purin bodies i grms per Salts Calories kilo 0.2 — 0.5 0.7 103. 2.4 — 0.7 1.0 104. 7. — 1.1 2.0 132. 3.9 — 1.0 1.0 124. 6. 1.3—2.0 1.1 133. 27. — 1.1 1. 213. 5. — 0.96 1. 150. 36. — — 0.8 390. 6. — 1.1 1.3 180. 8. — — 1. 220. 6. — 1.2 1.1 146. 37. — 0.5 0.7 406. 36. — 1.1 1.0 434. 0.2 1.2 varying 17.5 7. large amounts. 1.5 — 1.2 1.3 100. 0.2 20.0 0.02 1. 92. 0.8 78.5 — 1. 356. 1.5 68.3 — 0.7 350. 0.5 55.4 — 1.3 260. 6. 63. 0.53 3.0 177. 0.8 61. 0.39 2.6 344. 1.8 58.4 0.38 2.5 343. 1.8 51.5 0.63 3.1 330. 0.2 2.3 0.21 0.5 18.7 0.9 10.4 — 1.5 64. 0.3 2.1 — 1.0 16.6 182 THE PURIN BODIES Water Proteid Special Foods : Milk 88.5 3.4 Butter 13.2 0.8 Eggs 75.6 13.0 Cheese (fat) .... 37.8 27.2 Drinks : Beer, Lager 88.7 0.7 Ale 89.1 0.5 Porter 88.0 0.6 Tea — 0.6 Cocoa — 2.0 Chocolate — 5.1 Coffee — 0.5 Claret — — Sherry — — Brandy — — Fat Carbo- hydrates Purin bodies grms per Salts Calories kilo 3,6 4.8 _ 0.7 64. 85. — — 1.0 793. 11.0 — — 1.4 155. 30.0 2.5 — 1.5 404. 5.0 0.12 0.2 47.9 — 4.8 0.14 0.1 46. — 5.0 0.15 0.3 47. 1.0 per pint 1.2 6.5 2.0 4.0 1.0 — 43.2 15.2 74.9 0.7 — 469. 0.6 1.6 1.7 — 14.7 0.3 Alcohol 8.0 57.2 — 1.5 17.1 — 125.8 — — 45.0 — 315.0 Methods. Estimation of purin bodies in meats and meat extracts see p. 33. Estimation of purin bodies in vegetable foods see p. 37. Preparation of N nclein : — Minoe a thymus or pancreas gland thoroughly, or pass it several times through a sausage machine, and then macerate the pulp with four times its bulk of 0'5 per cent, solution of ammonia. Stir frequently. Strain through muslin, and similarly extract the residue several times. Mix the extracts together, and acidify with five per cent. HCl until a faintly acid reaction is obtained. OF FOOD STUFFS 183 The brown or dirty white precipitate is nuoleo-albumin. To prepare nuclein from this, add ten times its bulk of 0"2 per cent. HCl and 5 — 15cc. of liquor pepticus. Digest the mixture for 48 hours at 37°C upon a water bath or in an incubator. The albumin will have been split off as peptone, and the nuclein will be precipitated as a brown sediment. To purify it, filter, wash the residue with 0'2 per cent, hydrochloric acid, re-dissolve it in 0'5 per cent, ammonia solution, and re-precipitate it by the addition of five per cent, acetic acid. Repeat the process several times, and then weigh the purified nuclein. Boil an aliquot portion in 0'5 per cent, sulphuric acid for 12 hours and determine the quantity of purin-nitrogen as on p. 33. Preparation of Nucleic Acid: — The nuclein is decomposed by caustic soda, a sodium nucleate is formed, and the nucleic acid is freed by the addition of acid alcohol. Place a weighed quantity of nuclein in lOOco. of a 3 per cent, caustic soda solution. Stir the mixture during 5 — 10 minutes, make it neutral with 0'5 per cent, hydrochloric acid and then add acetic acid to precipitate the proteid. Filter and make up the filtrate to 200cc. Add occ. of 20 per cent, hydrochloric acid and 200cc. of 0"4 per cent, acid alcohol (hydrochloric) and collect the precipitated nucleic acid upon a hardened filter paper. Wash the residue into a small beaker, re-dissolve it in 0'5 per cent, ammonia solution and re-precipitate the nucleic acid by the addition of acid alcohol. Dry at 90°C then over sulphuric acid and weigh. 184 THE PURIX BODIES Pi-fparutlon of XucJeic Acid (after Neumann): — Place one kilo of pancreas or thymus in boiling water for a few minutes and weakly acidify. Then mince thoroughly and heat for half-an-hour in two litres of water, lOOcc. of 33 per cent, caustic soda solution, and 2()0grnis. of sodium acetate. Then neutralise with I.jOcc. of .")0 per cent, acetic acid, and filter whilst hot. Next at 40°C add an equal volume of alcohol, and allow the solution to cool. Filter and dissolve the residue in .500cc. of water, heating upon water bath .until the solution is quite clear. Filter and precipitate the nucleic acid with acid alcohol. Purify by dissolving in weak ammonia solution and re-precipitating with 0'5 per cent, hydrochloric acid. I'lepavation of GuanyJic Acid (after Ivor Bang): — Mince thoroughly one kilo of pancreas gland, and allow it to stand for 24 hours in one per cent, solution of sodium hydrate. Warm until the mixture pours easily, neutralise with acetic acid and then make it distinctly acid. Filter and boil the residue several times with water. Add all the filtrates together — they should yield ."i — 6 litres — filter again, make alkaline with 0'5 per cunt, ammonia solution and evaporate to 300cc. Warm, add 900cc. alcohol, allow to stand for four hours and then filter. Dissolve the residue in loOcc. of hot water and filter whilst hot. Boil the remainder several times, filter, add three volumes of alcohol to the filtrate, cool and filter. Wash the precipitate of guaiiylic acid with alcohol, alcohol and ether, and ether, dry over sulphuric acid and weiffh. OF FOOD STUFFS 185 Estimation of Phosphorus in Nucleins: — Fuse tlie substance in a platinum or silver capsule with a little caustic potash and potassium nitrate. This liberates the phosphorus from the organic matter, and it combines to form potassium phosphate. When cool, dissolve the mass in water, and acidify with nitric acid. Precipitate the phosphorus by adding about one-fourth of its bulk of a solution of ammonium molybdate containing nitric acid and a similar quantity of a saturated solution of ammonium nitrate. Place the mixture on a water bath at 50°C., collect the yellow precipitate of molybdium iJhosphate on a hardened filter paper, wash it with ammonium nitrate solution, and then dissolve it in 3 per cent, ammonia solution. Add some Ludwig's magnesia mixture, filter after 24 hours on a Schliecher and SchuU's No. 575 ash free filter paper, and incinerate. The ash, which consists of Mg^P^O,, may be weighed, and its phosphorus calculated. Estimation of "Carbohydrate" in Xiicleins : — Weigh about 0'2gm. of the dried nuolein, add to it lOOoo. of 20 jDer cent, sulphuric acid, heat on a water bath at 60 °C. for four hours. Filter, wash the residue with distilled water, titrate the filtrate with Fehling's solution, and calculate the inverted sugar in terms of dextrose. For further differentiation of xylose, pentose, etc., consult Grimd ("Zeit. f Physiolog. Chemie.," Bd. 35) or Bang (" Hoffmeister's Beitrage," s. 175, 1903). 186 THE PDRIN BODIES Estimation of Total Nitrogen (Kjeldahe) : — Incineration. Add 5 — 30cc. of concentrated pure sulphuric acid to about O'ogm. of organic matter or lOcc. of urine. Heat the mixture in a hardened Jena flask of about 300cc. capacity until it is quite clear and white in colour. This part of the process may be hastened by adding a few crystals of copper sulphate and about 3 grams of potassium sulphate or potassium pyro- phosphate. When the solution becomes light yellow in colour, the carbon has been nearly all oxidised to COj and the nitrogen changed into ammonia at first, and later into ammonium sulphate. A few crystals of pure potassium permanganate may be added to hasten the final stages. Except when filter papers or considerable quantities of organic matter require incineration, it is best to use sulphuric acid and the crystal of copper sulphate only, even if the process lasts over twelve hours. Distillation. Allow the contents of the combustion flask to cool. Meanwhile measure 10 — oOcc. of deci-normal sulphuric acid solution into a small Erlenmeyer's flask, add a few drops of neutral lacmus or alizarin solution, and connect the flask with the distillation apparatus, so that the block-tin tube just touches the fluid. When the incineration solution is quite cold wash it into a hardened glass distillation flask of about lOOOcc. capacity, and add about 10 — 20 grams of talc to prevent bumping. Talc is more satisfactory than zinc or glass tubing. Pour down the side of the flask a sufficient quantity of 33 per cent, caustic soda to make the mixture thoroughly alkaline. The reaction may usually be taken rapidly with litmus paper without any loss of ammonia. Attach the flask to the distillation apparatus, heat at first It has been lately pointed out that the addition of solid potassium permanganate frequently leads to loss of nitrogen, so that it should not be used when accurate estimations are desired. OF FOOD STUFFS 187 slightly, then strongly, and turn on the water at slow speed. Continue the distillation until the drops of distillate as they appear react neutral to litmus paper or to a drop of neutral lacmus or alizarin allowed to run down the tin tube so as to mix with the drop as it appears. Titration. It is more satisfactory to use a deci- normal solution of barium hydrate than one of sodium hydrate. Run the alkaline solution into the distillate until the lacmus turns blue or the alizarine turns yellow. Then deduct the number of cc. of alkali used from the number of cc. of acid taken and multiply the factor obtained by 0-0014. The figures obtained will give the amount of nitrogen in grammes contained in the substance taken. Estimation of Urea (Morner and Sjoqvist) : — Solutions required. 1. Saturated solution of barium chloride (with 5 per cent, baryta). 2. A mixture of 1 vol. ether and 2 vols, absolute alcohol (preferably in a wash-bottle). Take 5cc. of urine, 5cc. of barium mixture, lOOco. of the alcohol-ether mixture in a small stoppered flask and allow to stand for twelve hours. Filter and wash the precipitate with the alcohol-ether. Remove the alcohol and ether from the filtrate by evaporation at 55 °C. (not above 60°C.). When the liquid is reduced to 25cc. add a little magnesium oxide and about 15cc. of distilled water. Continue the evaporation, and when the ammonia is entirely removed and the fumes. 188 THE PURIN BOBIES are no longer alkaline in reaction add a few drops of concentrated pure suliDliuric acid. Now transfer the liquid to a Kjeldalil combustion flask, evaporate a little further, add 20cc. of strong sulphuric acid and estimate the nitrogen contents by Kjeldahl's process. To state the nitrogen in terms of urea multiply by 2'14:3. Estiination of Ammo7iia (Schlosing's method): — Take 25cc. of urine and place it in a flat glass dish with vertical sides, and mix it with 20cc. milk of lime. Into another similar vessel place 20cc. of deci-normal sulphuric acid. Cover both with a bell jar and allow to stand for several days. The sulphuric acid absorbs the ammonia after its expulsion by the lime, and the amounts of acid which has not been neutralised is determined by titration. This method gives rather low results. Estimation of Ammonia hy the Vacuum Method after Schittenhehn (" Zeit f. Physiolog. Chemie.," Bd. 39): — To 2.5 — .50cc. of urine (or equal quantity of solid tissues) add lOgms. sodium chloride and 1 gm. sodium carbonate. Place the flask in a water-bath and distil through iced water into 10 — 30cc. decinormal acid containing a few drops of rosolic acid. Produce a vacuum in the receiving flask and keep the water-bath at a definite temperature of 43°C. Replace the evaporated fluid in the distilling flask by a few cc. of water or alcohol run in through a separator funnel. The entire process should occupy 30 — 40 minutes. Carefully dis- connect the vacuum flask, allowing air to enter slowly. OF FOOD STUFFS 189 and titrate the distillate with deci-normal caustic soda or barium hydrate. Ex. 30oc. urine + 10gms. NaCl+lgm. Na^CO^ + 20cc. CoHjOH after twenty-five minutes at 43 °C. neutralised 7'03cc. deci-normal acid. This quantity equals 0-0119 NH3. Estimation of the Total Purin Bodies (Camerer-Arnstein). Solutions required. L Magnesia mixture. Magnesium chloride (crystal) ... llOgms. Anmionium chloride 110 „ Ammonia 250 „ Water to lOOOcc. 2. Ammoniacal silver nitrate. Silver nitrate 26gms. Water 300cc. Add ammonia until the silver oxide re-dissolves and dilute the solution to lOOOcc. 3. Ammonia solution (20 per cent.). To 24:Occ. of urine, from which all proteids have been removed by acidification and boiling, add 30cc. of magnesia mixture and 20cc. of the 20 per cent, ammonia solution. Allow to stand for 15 minutes and then filter. Take of the filtrate two portions of 125cc. each — 125cc. corresponds to lOOcc. of urine. To each add lOcc. of ammoniacal silver nitrate, and after a few minutes filter through an ash free filter paper of about lOcm. diameter. Wash out the vessel used for precipitation, with weak ammonia solution, and the precipitate with distilled 190 THE PUEIX BODIES water at 60°C until the washings are no longer alkaline. Transfer the filter paper and the precipitate to a Kjeldahl's combustion flask, add about 0'5gm. of magnesium oxide and boil the solution almost to dryness. Then add 20cc. concentrated pure sulphuric acid and a crystal of copper sulphate and determine the nitrogen contents by Kjeldahl's process. Modification by Purinometer. See page 149. Estimation of Uric Acid (tri-osy-purin) (Ludwig- Salkowski) : — Solutions required. 1. Magnesia mixture. Magnesium chloride llOgms. Ammonium chloride 110 „ Ammonia 250 „ Water to lOOOcc. 2. Silver nitrate solution 3p.c. 3. Sodium sulphide solution. lOgms. pure caustic soda dissolved in lOOOcc. of water. Divide into equal parts ; saturate one with sulphuretted hydrogen and then mix the two together. To 200ce. of urine add 50cc. magnesia mixture and oOcc. 20 per cent, ammonia solution. Filter, take 200oc. and add 10 — IB cc. of 3 per cent, silver nitrate solution. Wash the precipitate with weak ammonia solution and then with water, puncture the filter and wash the precipitate into another beaker. Heat to boiling OF FOOD STUFFS 191 10 — 20cc. of the sodium sulphide solution, and allow it to flow through the filter into the vessel containing the silver precipitate and then warm the contents on a water bath for 30 minutes, stirring constantly until the precipitate is entirely dark brown and no light specks are visible. Filter, add a few drops of concentrated hydrochloric acid, evaporate to about 15cc., add a few more drops of hydrochloric acid and allow to stand for 24 hours. The uric acid, which has crystallised out, should be transferred to a small paper, or, better, a glass wool filter, washed with a few cc. of water, alcohol, ether and carbon disulphide, and dried for four hours at 100°C. It may then be weighed, or its nitrogen determined by Kjeldahl's process. The amount of nitrogen found, multiplied by three, will give the quantity of uric acid in grammes in 13.3"3cc. For each lOcc. of the watery filtrate add 0'00048gms. uric acid to the quantity found directly. Hophins' method. Solutions required. 1. Pure ammonium chloride (free from iron and entirely soluble in water). 2. Pure ammonium sulphate. 3. Potassium permanganate solution Potassium permanganate l'578gm. Water 1 litre. Add 30gms. of ammonium chloride to lOOcc. of urine and shaie until the salt is dissolved. Now add Ice. of strong ammonia. Plug the flask with cotton wool and M 192 THE PURIN BODIES allow it to stand until the ammonium urate has settled and the upper layer of liquid is quite clear. This stage requires from one to two hours. Filter and wash out the vessel with a saturated solution of ammonium chloride, and also wash the precipitate with the same solution. Transfer the precipitate from the filter to a beaker by a jet of hot water. Not more than 30cc. of water should be used. If more has been taken, add Ice. of strong hydrochloric acid, concentrate on a water bath and then heat the solution to 90°C. Allow the uric acid to crystallise out and collect it on a hardened paper or glass wool filter, wash it with a few cc. of cold distilled water, alcohol and ether and weigh it. Instead of weighing, the first precipitate may be washed with a saturated solution of ammonium sulphate, transferred to a beaker, water added to lOOcc. 15cc. concentrated sulphuric acid are then run in and the mixture at once titrated with the permanganate solution. The end point is reached when the permanganate gives to the fluid a diffused pink flush. The colouration should be apparent throughout the solution, but rapidly dis- appears. The amount of cc. of permanganate solution used, multiplied by 0-00,375, will give the amount of uric acid in grammes contained in the lOOcc. of urine. Dimmock and Branson's modification, see p. 142. Estimation of the XantJiin or Piirin Bases :- Solutions required. 1. Magnesia mixture (see total purins). 2. Silver nitrate solution (3 per cent.). OF FOOD STUFFS 193 3. Potassium or sodium sulphide solution. Caustic potash 16 grammes. Water lOOOcc. Divide solution into equal parts, saturate one with sulphuretted hydrogen ; then mix the two together. To 500oc. of urine add 50cc. of magnesia mixture. Allow the phosphate to settle, then filter and take 400cc. of the filtrate for the estimation. Add 30oo. of the silver nitrate solution and a few cc. of strong ammonia solution, and filter after 1 — 2 hours. Wash the beaker and the precipitate with weak ammonia solution and with distilled water at 60 °C. Then transfer the precipitate to another beaker, decompose it with 30co. of the potassium sulphide solution or by H^S. Filter, acidify the filtrate with hydro- chloric acid and then evaporate the solution to lOcc. on a water-bath. Allow the fluid to stand for twelve hours, so that the uric acid may crystallize out. Remove the uric acid by filtration, make the filtrate thoroughly alkaline with ammonia and precipitate the purin bases by adding silver nitrate solution. Wash the purin-silver precipitate and the beaker, first with weak ammonia solution, then with distilled water at 60°C., until the washings are no longer alkaline. Then transfer the filter and precipitate to a combustion flask, add a little magnesium oxide and 50cc. of water, boil down to lOcc. and then determine the nitrogen contents by Kjeldahl's process. One gramme of nitrogen multiplied by 2' 625 gives the amount of xanthin or j)urin bases present. Or, the precipitate may be collected on a chlorine free filter, washed, incinerated, the ash dissolved in nitric acid 194 THE PUEIN BODIES and titrated with ammonium sulpho-cyanide (Igm. silver corresponds to 0'277gm. nitrogen or 0'738 purin bases). Estimation of Allantoiii: — 1. After LcBwi. Solutions required. 1. Solution of merourous nitrate (containing a little metallic mercury to prevent further oxidation). 2. Silver nitrate solution (3 per cent.). Add to 100 — 500cc. of urine excess of mercurous nitrate, filter, wash and saturate the filtrate with sulphuretted hydrogen. Remove the latter by evapora- tion, then add magnesium oxide and silver nitrate solution. Filter, wash with water, until the filtrate does not give a cloud with hydrochloric acid. Then determine the nitrogen by Kjeldahl's process. 2. After Poduschka. Solutions required. 1. Solution of basic lead acetate. 2. Solution of sodium sulphate. 3. Solution of silver nitrate. To 50 — lOOcc. of urine add an equal volume of basic lead acetate solution. Take an aliquot portion of the filtrate, add sodium sulphate solution to remove the overplus lead. Filter, add 20 — 30cc. of the silver nitrate solution and again filter. The filtrate should not give any precipitate on the addition of silver nitrate. Add to it a few drops of very weak ammonia solution and a large volume of silver nitrate solution. Allantoin is precipitated as white or greyish-white flocoulent masses. Filter, wash with a 1 per cent, solution of sodium sulphate OF POOD STUFFS 195 (perfectly free from ammonia), then estimate the nitrogen of the precipitate by Kjeldahl's process — Ice. -^sulphuric acid=0"0039gm. allantoin. Estimation of Chlorides. Solutions required. 1. Silver nitrate solution. Fused silver nitrate 29"075gms. Water lOOOcc. Ice. = 0"01gm. sodium chloride. 2. Potassium chromate (neutral). Saturated solution. Place lOcc. of urine and 90cc. of distilled water in a porcelain capsule, and add a few drops of the chromate solution until a distinct yellow colour is obtained. Take 25cc. of the silver nitrate solution in a burette, and, while stirring the diluted urine, run in the silver solution until an orange tint appears and remains after further agitation of the fluid. Deduct Ice. for the other urinary substances that combine with silver nitrate and multiply the number of cc. used by O'Ol. This gives the quantity of chlorides in lOcc. of urine. Estimation of Phosphates: — Solutions required. 1. Uranium nitrate solution. Uranium nitrate ... 35-5gm. Water ... lOOOcc. 2. Sodium acetate. Sodium acetate ... lOOgm, Glacial acetic acid ... lOOco. Water ... QOOce. i9d the purin bodies 3. Tinctura cocci B.P. Total phosphates. Take oOcc. of urine in a small flask and add 5oc. of the sodium acetate solution and sufficient cochineal to colour the mixture a decided red. Fill a burette with the uranium nitrate solution. Boil the urine and run in the uranium until a faint green colour appears and is uniformly diffused. Again bring the mixture to the boiling point, and if the green colour is not permanent continue to add the uranium. Multiply the number of co. used by 0.005 to obtain the quantity of P3O5 in 50cc. of urine. Earthy phosphates. Add strong ammonia solution to 200cc. of urine till it reacts strongly alkaline. Allow to stand for 12 hours. Collect the precipitate of earthy phosphates on a hardened filter, wash with dilute ammonia solution, remove from the filter paper to a porcelain basin, dissolve the phosphates by adding a few drops of acetic acid, warming if necessary, make up the mixture with distilled water to SOcc, add 5cc. of sodium acetate and run in the uranium nitrate solution. Alkaline phosphates. Subtract the amount of earthy phosphates from that of the total phosphates in 200cc. imiiiber of c aoo of urine and multiply the total dailj- urine by the factor resulting to obtain the amount of total alkaline phosphates. Estimation of Sulphates : — Solutions required. 1. Barium chloride solution. 2. Pure hydrochloric acid. 3. Pure sulphuric acid. OF FOOD STUFFS 197 Total sulphates. Add 5cc. of concentrated pure hydro- chloric acid to lOOcc. of urine, and boil in order to decompose the aromatic sulphates. Then add barium chloride solution until no more precipitate is produced. Collect the barium sulphate on a hardened ash free filter paper, wash with boiling distilled water until the wash- ings no longer give a precipitate with sulphuric acid. Dry the filter paper and residue from the washings- as well as the precipitate in an oven at 100°C., weigh a crucible, transfer the dried sulphates, incinerate, cool over sulphuric acid, add a few drops of sulphuric acid, carefully heat to redness, again cool in a dessicator, weigh and deduct the weight of the capsule.. This gives the quantity of barium sulphate (1 part of barium sulphate corresponds to 0'34:33 parts of sulphuric acid). Ethereal or aromatic sulphates. To lOOcc. of urine add lOOoc. of barium chloride solution. Filter very thoroughly through hardened filter paper. Take lOOcc. of the clear filtrate (corresponding to 50cc. of urine), add 5cc. of hydrochloric acid and heat just above boiling point for five minutes. Then add barium chloride solution until no more barium sulphate falls, collect the precipitate on an ash-free hardened filter, wash well with boiling distilled water, and dry the residue in an air-oven at 100°C. Weigh a capsule, transfer the precipitate, heat to redness, allow to cool and add a few drops of pure sulphuric acid, then re-heat carefully and weigh. Multiply the amount of barium sulphate by 0'34:33 to obtain the quantity of aromatic sulphates. It has been suggested that instead of gravimetric estimations the barium sulphate precipitate formed after the addition of hydrochloric acid and barium chloride in Modrakowski (Zdt.f. Phys. Chemie., 38, 1903) takes 2gm. sodium peroxide in a nickel dish, adds slowly 50cc. of urine, evaporates to a syrupy consistence, heats the mass with spirit lamp until fusion occurs, then dissolves mass in water, filters, acidifies filtrate with HCl and then precipitates as usual with BaCla- 19oi THE PURIN BODIES each, case, should be centrifugalised in a graduated tube and the amount of the precipitate recorded. This method gives very good results in regard to the relations existant between the aromatic and total sulphates. Estimation of Oxalates (after Autenrieth and Bartli. "Zeit. f. Physiolog. Chemie.," Bd. 35): — Solutions required. 1. Calcium chloride solution (saturated). 2. Ammonia solution (strong). 3. Hydrochloric acid, 15 per cent. 4. Ether-alcohol. Ether 97cc. Absolute alcohol ... 3oc. Take 500 — lOOOcc. of urine, add excess of calcium chloride and ammonia solution until the reaction is strongly alkaline. Shake thoroughly, and allow to stand twenty-four hours. Filter, dissolve the precipitate in 15 — 30cc. of 15 per cent, hydrochloric acid and then shake out the solution four or five times with 150 — 200cc. of the ether-alcohol mixture. Decant, allow to stand for an hour, remove the few drops of watery fluid remaining at the bottom of the vessel by passing the liquid through a dry filter and then distil the ether- alcohol extract. Evaporate the residue to about 5cc., add calcium chloride and ammonia to alkaline reaction, allow to stand for an hour and then preciiaitate the oxalate by adding weak acetic acid. After twenty-four hours collect the precipitate on a hardened filter of known OF FOOD STUFFS 199 weight, incinerate in a previously weighed capsule and then determine the weight of the calcium oxalate. Table op Measures. Solids (approximates). Vsoo grain = 000013 i gramme. /lOO " = 0-00065 )) /so " = 00013 )t /40 " = 00016 )j 1/ / 10 " = 0-0065 J, 1 = 0-065 „ 5 grains = 0-33 )j 10 „ = 0-66 )> 15-4 „ = 1 5> J ounce = 7-1 grammes. i = 14-2 j» 1 = 28 is \ pound = 112 )J h = 225 3J i-H = 450 3) 1 milligramme = Ve5 grain. 1 centigrajnme = \ jj 1 decigramme = 1-5 3) 1 gramme = 15-4 jj 10 grammes = i ounce. 28 = 1 jj 1 hectogramme =^ ounces. (lOOgms.) 1 kilogramme =2-35 pounds. 200 THE PURIN BODIES Liquids (approximates). 1 minim =0'06co. 1 drachm (fluid) = Ice. 1 ounce „ =30oc. 1 pint „ =568co. J gallon „ =2'26 litres. i „ „ =4-5 „ Ico. =16 minims. 4co. = 1 drachm (fjuid) 30co. = 1 ounce „ lOOcc. =3|^ ounces „ Atomic Weights. Aluminium Antimony Arsenic Barium Bismuth Lead ... Borium Bromine Cadmium Carbon Cerium Chlorine Chromium Cobalt Copper Erbium Fluorine Gallium Germanium 27-1 120 75 137-4 208-5 206-9 11 80 112-2 12 140 35-5 52-1 59 63-5 166 19 70 72 OP FOOD STUFFS 201 Gold .. 197'2 Hydrogen ... 1-01 Indium .. 114 Iodine .. 126 Iridium .. 193 Iron .. 56 Lithium .. 7 Magnesium .. 24-3 Manganese .. 55 Mercury . . . .. 200-3 Molybdium .. 96' Nitrogen . . . .. 14 Nickel .. 58-5 Osmium .. 191 Oxygen .. 16 Palladium .. 106 Phosphorus .. 31 Platinum ... .. 194-5 Potassium .. 391 Radium Selenium ... .. 79-1 Silica .. 28-4 Silver .. 107-9 Sodium .. 23 Strontium .. 87-6 Tellurium .. 128 Thallium ... .. 204-1 Tin .. 118-5 Tungstium .. 184 Uranium . . . .. 239-5 Zinc .. 65 INDEX. A. PAGE Abdominal diseases, purins in . 126 Absorption of guanin . 51 of hypoxanthin . 51 of nucleoproteids 51 of purins . 51 of xanthin . 51 of purins in rectal feeding . 51 of uric acid . 68 Acid Benzoate, action on purin ex cretion . . .132 gallic. .... 132 quinic ,, ,, .... 132 tannic ,, ,, ... 132 Action of food purins 50 Adenin, action on blood corpuscle i 54 action on cardiac muscle . . 54 action on kidney . 57 chemistry of . 11—14 in faeces .... . 103 AUantoin, after intra-peritoneal inj ections . . . .52 after rectal feeding . . 52 after hydrazin . . 109 after sulphonal 110 after uric acid feeding 109 cleavage product of uric acid . 12 estimation of . 194 in metabolism . . 110 in secretions . 110 Alcohol, effect on purin metabolisr n . . 94 Alcoholism, uric acid in . 121 ii INDEX Alkalies, action on purin excretion . Almen's method of proteid separation . Alloxan, cleavage product of uric acid . Alloxuric bodies bodies, action on nervous system . theory of nephritis . Amino purins, action on kidney Ammonia, estimation of . . . Anaemia, purins in . . . Arnstein's method for removal of ammonia Asparagus, effect on purin excretion . purins in . Aspirin, action on purin excretion . Atomic weights Atropin, action on purin excretion . Autolysis, effect on purin contents . PAGE . 132 26 13 15 58 129 57 188 120 34 92 46 132 200 132 110 B. Bacterial growth and purins Beans, effect on purin excretion purins in . Beckmann's method of proteid separation Beef extract, action on pulse . action on liver, etc. purins in . . Beer, effect on purin metabolism purins in . Beverages, methods of extraction in purins in . metabolism of purins Birds, urinary xanthin bases Blood corpuscles, action of hypoxanthin on pressure after guanylic acid . purins in .... Bread, purins in . . . Butter, purins in Burian, on methods 94, INDEX Cabbage, purins in . Caffeine, action on circulation action on digestion . action on heart action on nervous system action on respiration chemistry of . Caffeine in purin metabolism . Calculi, purins in . mode of action on cells . Calories, effect on purin excretion . Camerer-Arnstein, method for purins Carbohydrate in nucleins . Carcinoma, purins in Cauliflower, purins in . Cereals, purins in . . Chlorides, estimation of . Champagne, effect on uric acid excretion Cheese, purins in . Chicken, purins in . Child, endogenous purins in . Coagulation, after caffeine, in frogs rate of, after guanylic acid . COj elimination after tea and coffee elimination after caffeine elimination after hypoxanthin elimination after uric acid Cod, purins in Coffee, purins in ... . Colchi-sal, action on purin excretion Critical summary of methods . PAGE , 46 52 52 52 53 58 55 56 11- -14 98 18 98 86 , 87 189 185 120 46 46 195 94 48 41 93 59 55 55 62 62 62 40 48 132 24—38 D. Demethylation 55 iv INDEX Diphtheria, xanthins in . Diuresis and methylpurins Drugs, action on purin excretion . action on purin excretion Diabetes, xanthin in PAGE 122 57 131 127 122 E. Eggs, purins in Endogenous purins . purin in child . Enemata, purins in . uric acid after Estimations of purins in foods Exogenous purins 48 17 93 51 109 24 17 FfEces, purins of .... . , 99 Fseces, purins of, method of estimation 100 purins of . . . 103 Fat in meat . . 39 Fever, purins in . 120 Ferment action in purin metabolism .... 130 Fish scales, guanin in .... 18 purins in . 40 free and bound purins 42 total extractives 43 total nitrogen . . . . . 43 Formaldehyde in proteid separation 28 G. Gastric diseases, purins in juice, action of purins on Glycocoll, cleavage product of purin bodies Gout and perverted metabolism beef in ... . 126 50 13 94 77 INDEX PAGE Gout, exogenous purins in 126 chicken in ... . . 19 red meats in . . 19 soups in . . 19 sweetbread in . 19 endogenous purins . 126 ■ effect of wines on . 98 guaiacum in . 138 liver functions in . 136 purins in 78, 120 renal theory of . 130 ■ salicylate of soda in . 134 • uric acid in ... . . 121 Guanin, action on blood corpuscles . . 54 Guanylic acid, action on blood pressure . 55 action on heart . 5j action on pulse . . 55 Guanin, action on tissues . 77 chemistry of . 11—14 in fseces . 103 in fish scales . 18 preparation of . 71 Guanylic acid, preparatior 1 of . . 184 H. Halibut, purins in . 40 Ham, purins in . 41 Hsematemesis, purins in . 126 His and Hagen on methods .... 28 Hypoxanthin, action on blood pressure . 72, 73 action on blood corpuscles 74, 76 CO, elimination 63 action on kidney . 75 action on liver . 76 action on muscle . 59 INDEX Hypoxanthin, chemistry of ■ in faeces . PAGE 11—14 . 103 Injections, intravenous uric acid after Intestinal diseases, purins in . 109 120 K. Kidneys, action of hypoxanthin on . Kidney, changes after hypoxanthin relation to uric acid metabolism 75 57 129 L. Leucopenia and uric acid Leucocytosis and uric acid Lentils, purins in Lettuce, purins in . Leukfemia, purins in Liebig's extract, diarrhoea from Liver, action of purins on cirrhosis, uric acid in in gout .... purins in seat of uric acid metabolism Lithium benzoate, action on purin excretion Ludwig-Salkowski, method for uric acid Lysidine, action on purin excretion Lymph flow and composition after nucleic acid M. 82 81 46 46 120 51 76 121 136 41 118 132 190 132 55 Measures, table of, solids table of, liquids Meat extracts, purins in . Meats, free and bound purins 199 200 17 42 INDEX PAGE Metabolism, fermentation in 130 Malaria, purins in ... . .... 120 Marrow, action of purins on 75 Meat, fat in 39 Meats, light and dark 19 Meat, total extractives 43 total nitrogen 43 Metabolism, action of purins on 60 of beverages in purins 93 of exogenous purins Ill, 112 effect of calories on purin ..... 87, 88 proteid-effect on purin excretion . . . . 87, 80 of vegetable purins 89 nuclein, in dogs ........ 95 perverted by beer .94 purin, effect of alcoholism .... .94 Methods of estimation 24 Method of estimating ftecal purins . . . . . .100 of extraction, etc., in vegetables and beverages . . 38 Methyl purins, action on nervous system . . . .58 purins, as diuretics 57 Methylation and demethylation 55 Methyl purins, effect on purin excretion ... .98 purins, mode of action on cells ... .98 Milk, purins in 48, 49 Muscles, relation to uric acid metabolism .... 130 Mutton, purins in 40 Myoproteid 36 N. Narcosis, after guanylic acid . Neu-Sidonal, action on purin excretion Nephritis, purins in . relation to purin bodies . red and white meats in . souDs in . 54, 55 132 120 77 19 19 viii INDEX Nephritis, theory of alloxur causation xanthins in Nitrogen, effect on purin excretion . Kjeldahl's method Nucleic acid, action on blood corpuscles acid, action on drosera acid, chemistry of acid, preparation of Nuclein, chemistry of Nucleins, carbohydrate in Nuclein, cleavage products cleavage products preparation of Nucleins, relation to uric acid intestinal changes in Nuclein, in fasces metabolism in dogs synthesis of Nucleins, slowness of excretion Nucleo proteid, chemistry of . PAGE 129 122 87 186 54 54 16 183 16 185 115 82 182 81 101 103 95 80 107 16 0. Oatmeal, purins in . Offer and Rosenqvist's method Onions, purins in . . . Oxaluria and uric acid Oxalates in urine, estimation of 46 35 46 130 198 Pancreas, purins in . Peameal, purins in . Peas, effect on purin excretion Pentose . ... Pernicious anaemia, purins in . Phosphates, estimation of Phosphorus, estimation of 17 46 90 16 120 195 185 INDEX PAGE Piperazin, action on purin excretion . . . .132 Piperidin, action on purin excretion 132 Plaice, purins in ... . 40 Plumbism, purins in . 120 Pneumonia, purins in . . . 120 uric acid in ... . 121 Pork, purins in . 40 Porter, purins in ... 48 Potatoes, purins in ... 46 Pulses, purins in ... . 46 Purins, action on gastric juice . 50 action on blood pressures 72, 73 action on blood corpuscles 74 action on heart . . . 52 action on CO^ production 62 action on kidneys .... 75 action on marrow .... 75 action on liver .... . 76 action on metabolism .... 60 action on saliva . 50 action of drugs on . . . 131 amino action on kidney .... . 57 and bacterial growth . 61 bases, estimation in urine 85, 192 chemistry of . , . . . . . 11, 12, 13, U endogenous ... 17, 114 early estimations of .... . 22 excretion, effect of beans on 90, 91 excretion, effect of beer on . . 96 excretion, effect of lentils on . 90 effect of peas on . . . . 90 excretion, hepatic stimulation in . 138 exogenous . 107 exogenous 111 estimation of, in meats . . 33, 182 estimation of, in vegetables . . 37, 182 estimation in urine . . 140 INDEX PAGE Purins, elementary analysis of precipitate . . 31 free and bound .... . 42 in autolysis 110 in beverages .... . . . 48 • in blood stream . 116 in cereals . . 46 in exudates . . . . . 121 in meat extracts . 17 in morbid conditions . 120 in pulses . 46 in thymus and pancreas 17 in tissue fluids . 116 in urfemia . 121 in urine, estimation of . 189 in vegetables . . . . 17, 44, 46 metabolism, action of ferments on . 130 metabolism, effect of alcoholism . 94 metabolism, effect of beverages . 93 metabolism, effect of calories of, on 86, 87 metabolism, effect of nitrogen on . 86, 87 methods of extraction .... 24 methyl, action on nervous system . . 58 methyl, as diuretics 56, 57 methyl, relation to uric acid . . 82 nucleus, action on muscle .... . 58 oxidation of . 17 rate of excretion of . . 68 relation to uric acid . 80 Purinometer . .... . 150 Pyrimidin .... ... . 58 R. Rabbit, purins in 41 Rate of purin excretion 68 Rice, purins in 46 INDEX S. Salkowski, method for uric acid Salicylate, action on uric acid destruction Saliva, action of purins on Salmon, purins in . . . Scarlatina, endogenous purins in xanthins in . . Sherry, effect on purin metabolism Sidonal, action on purin excretion Splenic extract, action on heart Sodium acetate, action on purin excretion benzoate, action on purin excretion — — salicylate, action on purin excretion salts hinder excretion Sweetbread, purins in ... . PAUE 190 130 50 40 126 122 94 132 54 132 132 132 132 41 T. Tapioca, purins in . Tannic acid method .... acid, Almen's solution . Tea distillates, action on respiration Theobromine, chemistry of action on digestion . Theophyllin Tripe, purins in ... . Thymus, purins in . Turkey, purins in ... . Typhus fever, purins in . . 46 . 26 26 . 56 11—14 . 52 . 14 . 40 17, 41 . 41 . 120 U. Uracil . . . , Urea, estimation of . relation to uric acid relation to purins Uric acid, absorption of . 58 187 13, 108 . 15 . 68 xii INDEX TAGK Uric acid, aclion on mucosa 51 acid, after allantoin . ... 109 acid, after nucleic acid . . 109 acid, after rectal injections . . 109 acid and bacterial growth . . 61 acid and proteid foods . . . . .80 acid and leucocytosis . . 82 acid and urea quotient . . . 108 acid, chemistry of . . . 11 — 14 acid, destruction by tissues . . . 129 acid, effect of alcohol on ... 94 acid, effect of champagne on . . . 94 acid, effect of beer on . . .94 acid, effect of mixed diets on . . . S3 acid, elimination by drugs . 130 acid, estimation of . 141, 190 acid, fate in the body ... . . 112 acid, intravenous injection of . . . 129 acid and oxaluria ... . 130 acid in morbid conditions 120 acid. Mare's theory . . . .80 acid, seat of formation . 117 acid, relation to nitrogen hunger 81 acid, relation to nucleins . 81 acid relations to methylpurins 82 acid, synthetic theory . . 80 acid, toxic action .... .113 Urine, oxalates, estimation of . . . 198 phosphates, estimation of total . 196 phosphates, estimation of earthy . 196 phosphates, estimation of alkaline . 196 purin bases, estimation of . 192 xanthin, estimation of .... . 192 purins, estimation of . .... 189 sulphates, estimation of total . 197 sulphates, estimation of ethereal or aromatic . 197 uric acid, estimation of 190 of birds 85 INDEX Urine, xanthin, bases of Urosine, action on purin excretion . Urotropine, action on purin excretion PAGE 85 132 132 V. Veal, purins in 40 Vegetables, method of extraction 38 purins in 17, 46 Vernin ........... 17 W. Water, action on purin excretion . Weight, relation to purin excretion Wines, purins in ... . 132 118 48 X. Xanthin, action on cardiac muscle . . 53 action on nervous system . . 58 bases in urine . . 85 chemistry of . 11—14 earlier estimations in food . 21 Xanthins, estimation in urine . . 192 Xanthin in faeces . 103 Xanthins in morbid conditions . 121 Xylose ..... • . 16 Zinc sulphate in proteid separation 27 Sherratt & Hughes Printers and Publishers London and Manchester