352 PHYSIOLOGICAL CHEMISTRY. 



proved. With regard to the pathological relations we really only 

 know two conditions in which the elimination of uric acid is 

 increased, namely, in fever and leucaemia. In fevers the elimina- 

 tion of uric acid is increased because of an increased waste of the 

 organism. In leucaemia the elimination is increased absolutely as 

 well as relatively to the urea (RANKE, SALKOWSKI, FLEISCHER and 

 PENZOLDT, STADTHAGEN, and others), and the relationship of the 

 elimination of uric acid to the urea may be 1 : 16-1 : 12. The 

 elimination of uric acid may be diminished in gout shortly before 

 and during the attack, because the uric acid is retained in the 

 body. A decrease in the elimination of uric acid is observed also in 

 a diminished exchange of material, also after the use of quinine, 

 caffeine, and certain other medicines. 



Formation of Uric Acid in the organism. The formation of uric 

 acid in birds is increased by the administration of ammonia-salts 

 (v. SCHRODER). Urea acts in the same way (MEYER and JAFFE), 

 while in the organism of mammalia uric acid is more or less com- 

 pletely converted into urea. MLFKOWSKI observed in geese with 

 their livers extirpated a very significant decrease in the elimination 

 of uric acid, while the elimination of ammonia is increased to a 

 corresponding degree. This indicates a participation of ammonia 

 in the formation of uric acid in the organism of birds ; and as 

 MIKKOWSKI has also found after the extirpation of the liver that 

 considerable amounts of lactic acid occur in the urine, it is prob- 

 able that the uric acid in birds is produced in the liver, perhaps 

 from lactic acid and ammonia by synthesis. Amido-acids leucin, 

 glycocoll, and aspartic acid increase the elimination of uric acid in 

 birds (v. KNTERIEM), but whether the amido-acids are first decom- 

 posed with the splitting off of ammonia is still unknown, v. MACH 

 has shown that a small part of the uric acid in birds originates from 

 hypoxanthin, and a similar origin for the uric acid of mammalia is 

 also very probable (MINKOWSKI). 



After the extirpation of the kidneys of snakes and birds 

 V. SCHRODER has observed an accumulation of uric acid in the blood 

 and tissues. . This shows that the kidneys of these animals are not 

 the only source of uric acid, and any direct proof of the formation 

 of this acid in the kidneys has not to the present time been demon- 

 strated. A direct relationship between the spleen and the forma- 



