URINE. 115 



and soda, and lie conceives that, in all probability, the uric acid 

 is held in solution through the agency of some of the other con- 

 stituents of the urine. 



[Liebig 1 has shown that uric acid possesses the property of 

 combining with a portion of the soda of the alkaline phosphate 

 of soda, and acquires in the combination a higher degree of 

 solubility than it possesses in its uncombined state, at the ordi- 

 nary temperature of the body. By this reaction there are 

 produced a urate of soda and an acid phosphate of soda.] 



Prout, on the contrary, is of opinion that the uric acid is held 

 in solution in the urine in the state of urate of ammonia, a 

 combination which probably always occurs in healthy urine, and 

 which is often found in large quantity in the urine of diseased 

 persons, giving rise to the formation of sediments. The real 

 state of the case may be, that normal urine contains both free 

 uric acid and urate of ammonia. 



Qualitative analysis of healthy urine. 



The qualitative analysis of healthy urine seldom presents any 

 great difficulty. Many of its constituents may be detected with 

 ease, unless, as is sometimes the case, they exist in very minute 

 quantity. Others, as for instance, the extractive matters, can 

 only be detected with any degree of certainty by isolating them, 

 in the same manner as is done in quantitative analysis. 



The analysis of the urine is something like that of mineral 

 waters ; some of the constituents may be at once recognised by 

 the addition of a test, while we can only be assured of the pre- 

 sence of others, by separating them in a distinct and iso- 

 lated state. 



The specific gravity of the urine is most accurately deter- 

 mined by the ordinary 1000-grain glass bottle. An areometer 

 will give the result with less trouble, but, at the same time, 

 with less accuracy. 



Becquerel 2 has published a table for the purpose of enabling 

 us to calculate the amount of the solid constituents in a known 

 weight of urine, from the observed specific gravity, [but it has 



1 Lancet, June 1844. 2 Semeiotique cles Urines, p. 17. 



