214 



THE BODY AT WORK 



we gave as the predominant cause of gout acid fermentations 

 in the stomach. It does not, by any means, follow, however, 

 that we were right in correlating imperfect digestion with an 

 excessive formation of uric acid. It may well be that the gouty 

 symptoms to which hampered peptic digestion gives rise are 

 due in larger measure to a disturbance of the composition of 

 the body-fluids which renders them unfit to carry uric acid to 

 the kidneys in such a form, or in such relation to the fluid in 

 which it is dissolved, as will insure its escape into the urinary 

 tubules. The interference with the efficient working of the 

 system caused by accumulation in it of uric acid gives a par- 

 ticular interest to all that is known regarding the nature and 

 origin of this substance. 



Uric acid has the formula C 5 H 4 N 4 3 . It is a more com- 

 plicated and a more stable body than urea. The deposits of 

 guano in Peru contain uric acid (the excrement of birds) which 

 has remained practically unchanged for years for centuries, 

 perhaps. Its chemical nature is not completely understood. 

 It can be readily made to yield urea ; and it can be formed by 

 conjugating urea with a nucleus derived from lactic acid 

 (cf. p. 13). Its formula is therefore commonly represented as 

 that of a diureide a substance containing two urea radicles : 



fHN CO 



CO 



HN 



NH 



NH 



CO 



But notwithstanding this inclusion in its molecule of two 

 radicles of urea, it is safe, when one thinks of the contrast 

 between urea and uric acid, to lay stress, in the case of the 

 former, on the binding of nitrogen to hydrogen ; in the case of 

 the latter, on the binding of nitrogen to carbon. 



Uric acid is soluble with difficulty ; it crystallizes in rhombs. 

 It forms salts, normal and acid. Those which appear in the 

 urine are always acid salts. As a treatment for " stone," 

 lithia water has long had a reputation which it probably 

 deserves, the acid urate of lithium being the most soluble salt 



