204 EXCRETION. 



The lactates of soda, potassa, and lime exist in very con- 

 siderable proportion in the normal urine. They are un- 

 doubtedly derived immediately from the blood, passing, 

 ready-formed, into the urine, where they exist in simple wa- 

 tery solution. According to Robin, the lactates are formed 

 in the muscles, in the substance of which they can be read- 

 ily detected. 1 We have no positive information with regard 

 to the precise mode of formation of these salts. It is prob- 

 able, however, that the lactic acid is the result of transfor- 

 mation of glucose. As a curious chemical fact, it is inter- 

 esting to note that the lactic acid contained in the lactates 

 extracted from the muscular substance is not absolutely 

 identical w^ith the acid resulting from the transformation of 

 the sugars. The former have been called paralactates, and 

 they contain one equivalent of water less than the ordinary 

 lactates. According to Robin, the compounds of lactic acid 

 in the urine are in the form of paralactates. 3 



Although the inosates (compounds of inosine, C 12 H 12 O 12 ) 

 have never been detected in the urine, Robin is of the opinion 

 that traces of these salts are separated from the blood by 

 the ,kidneys, from the fact that they exist normally in the 

 blood and in the muscular tissue. 3 



We have little or no information with regard to the re- 

 lations of the inosates to excretion. 



Creatine, C 8 H 9 O 4 N S + 2HO, and Oreatmme, C 8 H 7 O 2 3 . 



Creatine and creatinine are undoubtedly identical in 

 their relations to the general process of disassimilation, for 

 one is easily converted into the other, out of the body, by 

 very simple chemical means ; and there is every reason to 

 suppose that, in the organism, they are the products of 

 physiological waste of the same tissue or tissues. These 

 principles have been found in the urine, blood, muscular 



1 ROBIN, Lemons sur les humeurs, Paris, 1867, p. 681. 



2 Loc. cit. 3 Loc. cit. 



