COMPOHtO)S OF URIC ACID. 201 



found in urinary deposits, where it is interesting to study the 

 peculiar and varied forms of its crystals. Frequently, in ta- 

 bles of the composition of the urine, the proportion of uric 

 acid is given, but this is simply a matter of convenience, and 

 has precisely the same signification as the estimates of the 

 proportions of sulphuric or phosphoric acid. None of these 

 acids constitute, of themselves, proximate principles of the 

 urine, but are always combined with bases. 



In normal urine, uric acid is combined with soda, ammo- 

 nia, potassa, lime, and magnesia. Of these combinations, 

 the urate of soda and the urate of ammonia are by far the 

 most important and constitute the great proportion of the 

 urates, the urates of potassa, lime, and magnesia existing 

 only in minute traces. The urate of soda is very much more 

 abundant than the urate of ammonia. 1 The union of uric 

 acid with the bases is very feeble. If from any cause the 

 urine become excessively acid after its emission, a deposit 

 of uric acid is liable to occur. The addition of a very small 

 quantity of almost any acid is sufficient to decompose the 

 urates, when the uric acid appears after a few hours in a 

 crystalline form. 



Uric acid, probably in combination with bases, was found 

 in the substance of the liver in large quantity by Cloetta ; a 

 and his observations have been confirmed by recent German 

 authorities. 8 It is more than probable that the urates also 

 exist in the blood and pass ready-formed into the urine; 

 but their proportion in the blood is so slight under normal 

 conditions, that their presence in this fluid has not been defi- 



1 The urates of soda exist in two forms ; the neutral urate, in which there 

 is one equivalent of the acid, and the acid urate, with two equivalents of acid. 

 There are likewise neutral and acid urates of ammonia. The neutral salts exist 

 hi by far the larger quantity. 



2 CLOETTA, De la presence de Vinosite, de facide urique, etc., dans diverse* par- 

 ties du corps animal. Journal de la physiologic, Paris, 1858, tome i., p. 802. 

 Cloetta also noted the presence of uric acid in the substance of the spleen. 



3 MEISSKER, op. tit. Centralblatt fur die meditinischen Wissenschaften, 1868, 

 No. 15, S. 226, et seq. 



