LACTIC ACID. 101 



of diabetic urine containing sugar, these experiments were of less 

 weight than those of Scherer. We may hence fairly conclude 

 that the urine, after its excretion from the kidneys, undergoes a 

 similar acidification in the bladder, and consequently that the 

 lactic acid which is often found in the urine discharged from that 

 viscus is a product of decomposition which is formed externally 

 to the sphere of vital activity. If, however, the occurrence of 

 crystals of free uric acid warrants us in inferring the existence of 

 the lactic fermentation, it is only very seldom that it can occur in 

 the bladder, for the cases are extremely rare in which urine on its 

 emission from that organ contains free uric acid; the statement 

 that has found its way into various books, to the effect that fresh 

 urine often contains free uric acid, being a very erroneous one. 



C. Schmidt * has separated lactic acid in the form of lactate of 

 zinc, from the strongly acid fluid yielded by the long bones in a 

 case of osteomalacia. He measured the angles of the crystals, and 

 submitted the salt to an elementary analysis. 



Origin. If we might be permitted to hazard a conjecture 

 regarding the production of lactic acid from its occurrence in the 

 animal body, we should ascribe to it a double origin. No one can 

 entertain a doubt that the lactic acid, found in the contents of the 

 intestine and in the chyle after the digestion of vegetables, owes its 

 formation to the amylaceous or saccharine matters contained in the 

 food, which in their passage through the primce vice become 

 converted into that acid, in the same manner as takes place in the 

 fermentation of milk. But the true genesis of the lactic acid 

 which accumulates in such large quantity in the muscles is not so 

 immediately obvious ; we may certainly assume that the lactic 

 acid formed in the primoe vice from vegetables is especially 

 attracted by some mechanical or chemical influence of the 

 muscular fibre, and is accumulated there to serve certain definite 

 purposes; but this view is in some measure opposed by the 

 circumstances that the muscles of carnivorous animals contain as 

 much lactic acid as those of herbivorous animals, and that free 

 lactic acid is always found in the urine of carnivora and of men 

 when living on a strictly animal diet, which would scarcely be 

 the case if the acid conveyed to the muscles solely proceeded 

 from the lactic acid contained in the flesh which had been taken 

 as food. But if we regard the lactic acid of the juice of flesh, 

 merely as a product of metamorphosis which is formed while the 



* Ann. d. Ch. u. Pharm. Bd. 61, S. 302-306. 



