THE CHEMISTRY OF THE ANIMAL BODY. 999 



in the body in some way have lesser opportunities for oxidation than those 

 introduced into it. Experiments on this same ease have shown that, though 

 the proportion of daily uric-acid nitrogen to total nitrogen in the urine may 

 vary considerably (1 : 63 to 1 : 88), the proportion of the nitrogen of uric acid 

 plus the bases to total nitrogen is quite constant (1 : 48.3 to 1 : 40.8) ; from 

 this may be inferred that there is greater or less production of uric acid through 

 oxidation of the bases on different days. This may be interpreted as affording 

 the missing link in explanation of the conversion of the bases into uric acid. 

 If xanthin itself be fed, it is not converted into uric acid. According to 

 Horbaczewski, 1 uric acid is produced from nuclein by digesting putrid extract 

 of the spleen with blood. 



Xanthin fed to birds is converted into uric acid. In birds the formation of uric acid 

 depends on a synthetic union of ammonia and lactic acid in the liver, since on extirpation 

 of the liver the last two substances appear in the urine in amounts proportional to the 

 normally formed uric acid (see p. 989). 



The literature on the subject of gout is enormous. It is sufficient to re- 

 mark here that it is not even known whether gout is due to an increased for- 

 mation or an increased retention of uric acid. The amount of uric acid in the 

 blood is certainly increased. The normal amount of uric acid in the daily 

 urine is put at 0.7 gram, that of the alloxuric bases at 0.1325. 2 The amount 

 of the bases may be quadrupled in leucocythsemia. 3 Whether all the alloxuric 

 bodies produced in the organism are eliminated, or whether they are partially 

 burned, is a matter of controversy. 



DIATOMIC DIBASIC ACIDS, C n H 2n _ 2 O 4 . 



COOH 



Oxalic Acid, I . This is found as calcium oxalate in the urine, and 



COOH 



is present in most plants. Its possible origin from uric acid has been men- 

 tioned. It is a product of boiling proteid with barium hydrate. It may be 

 obtained synthetically by heating sodium formate : 



COONa 



2HCOONa=| + 2H. 



COONa 



Oxalic acid and its alkaline salts are very soluble in water. Its calcium salts 

 are insoluble in water and dilute acetic acid, but are soluble in the acid phos- 

 phates of the urine. 



If oxalic acid be given subcutaneously it appears unchanged in the urine. 4 

 Given per os it undoubtedly unites with the calcium salts of the gastric and 

 other juices, and is therefore but partially absorbed. After feeding a man 

 with meat alone, or with meat, fat, and sugar, Bunge 5 could find no oxalates 



1 Loc. tit. 2 Kriiger and Wulff : Zeitschrift fur physiologische Chemie, 1895, Bd. 20, p. 184. 



3 Boudzynski and Gottlieb, Op. cit., p. 132. 



4 Gaglia: Archivfur exper. Pathologic und Pharmakologie, 1887, Bd. 22, p. 246. 



5 Physiologische Chemie, 1894, p. 340. 



