CREATIXINE. URATE OF SODA. 



347 



alkaline reaction. It occurs, like creatine, in the muscles, the blood, 

 and the urine ; and is undoubtedly first produced in the muscular 

 tissue, to be discharged finally by the kidneys. It is very possible 

 that it originates, not directly from the muscles, but indirectly, by 

 transformation of a part of the creatine ; since it may be artificially 

 produced, as we have already mentioned, by transformation of the 

 latter substance under the influence of strong acids, and since, fur- 

 thermore, while creatine is more abundant in the muscles than 

 creatimne, in the urine, on the contrary, there is a larger quantity 

 of creatinine than of creatine. Both these substances have been 

 found in the muscles and in the urine of the lower animals. 



URATE OF SODA. As its name implies, this substance is a neu- 

 tral salt, formed by the union of soda, as a base, with a nitrogenous 

 animal acid, viz., uric acid (C 5 HN 2 2 ,HO). Uric acid is sometimes 

 spoken of as though it were itself a proximate principle, and a 

 constituent of the urine; but it cannot properly be regarded as 

 such, since it never occurs in a free state, in a natural condition of 

 the fluids. When present, it has always been produced by decom- 

 position of the urate of soda. 



Urate of soda is readily soluble in hot water, from which a large 

 portion again deposits on cooling. It is slightly soluble in alcohol, 

 and insoluble in ether. It 



crystallizes in small globu- Fig. 114. 



lar masses, with projecting, 

 curved, conical, wart-like 

 excrescences. (Fig. 114.) It 

 dissolves readily in the alka- 

 lies ; and by most acid solu- 

 tions it is decomposed, with 

 the production of free uric 

 acid. 



Urate of soda exists in 

 the urine and in the blood. 

 It is either produced origin- 

 ally in the blood, or is formed 

 in some of the solid tissues, 

 and absorbed from them by 

 the circulating fluid. It is 



constantly eliminated by the kidneys, in company with the other 

 ingredients of the urine. The average daily quantity of urate of 



URATE OF SODA ; from a urinary deposit. 



