124 THE SECRETIONS: 



salts, it might have been supposed that the neutral lactates 

 formed upon the neutralization of the urine with the two bases 

 had been decomposed, together with the phosphates of soda and 

 potash contained in the urine, and transposed themselves anew, 

 with these substances, into phosphate of baryta or of magnesia, 

 and into neutral lactate of potash or soda. In this case neither 

 baryta nor magnesia could remain in solution. This circum- 

 stance, therefore, renders these experiments indecisive, and 

 leaves the question as to the presence or absence of lactic acid 

 in urine dependent upon more direct experiments. 



" I employed putrid urine in my attempts to detect lactic 

 acid, because lactic acid is not destroyed by putrefaction, and it 

 must, therefore, of necessity be present in putrid urine if it 

 really forms a constituent of fresh urine ; and because if lactic 

 acid can at all be formed by the putrefaction of urine, from 

 matters containing previously no lactic acid, the question whether 

 lactic acid is to be reckoned among the constituents of normal 

 urine is at once practically decided; or, more correctly speak- 

 ing, the problem is proved to be impossible of solution, since 

 we possess no means of positively determining which urine may 

 be considered of a normal constitution, and, on the contrary, 

 which is, to this extent, abnormal. 



" As matters at present stand, therefore, with regard to this 

 subject, it was immaterial whether the presence of lactic acid 

 was detected in fresh or in putrid urine ; if it was found to exist 

 in the latter, this fact must be considered as a confirmation of 

 Berzelius' examination of fresh urine ; whilst its absence from 

 putrid urine would justify us positively in asserting that it does 

 not form a constituent of fresh urine ; and, moreover, that urine 

 contains no substance giving origin, by means of putrefaction, 

 to the formation of lactic acid. 



" I have come to the latter conclusion. I have found it im- 

 possible to detect the presence of lactic acid in putrid urine ; 

 and if we examine somewhat more closely and minutely the 

 experiments made by Berzelius, and from which he inferred the 

 presence of lactic acid in urine, we find that not one of them 

 amounts to a positive proof that lactic acid really forms a con- 

 stituent of fresh urine. 



" The experiments which I made for the purpose of ascer- 



