ALKALINE CARBONATES IN THE BLOOD. 239 



acid. Ranke 5 * who commenced under my direction a more minute 

 examination of this subject, has now obtained the undoubted result, 

 that salicylic acid is formed in addition to salicylous acid ; he also 

 obtained considerable quantities of phenylic acid by the distillation 

 of the alcoholic extract of such urine with water. I have, however, 

 not convinced myself that this acid is contained preformed in this 

 urine ; it may very readily occur here as a product of distillation. 

 Phenylic acid exerts an extremely poisonous action, so that some 

 symptoms of indisposition ought to manifest themselves after the 

 use of salicin, if this acid were formed from salicin ; such, however, 

 is not the case. As it might be conjectured that phenylic acid was 

 separated from the kidneys immediately on its formation, I injected 

 the alcoholic extract of this urine into the jugular vein of a rabbit, 

 but the animal exhibited no morbid symptoms whatever. 



I may here observe in reference to the decomposition of salicin 

 in the animal organism, that this substance, which, like amygdalin, 

 is decomposed by synaptase, does not behave in the blood in the 

 same manner as amygdalin, which on being injected into the blood 

 is not decomposed, and hence does not produce poisoning by 

 prussic acid; although when salicin is injected, a portion only 

 passes in an unaltered state into the urine, whilst the larger quan- 

 tity is decomposed in the blood ; for after the injection of salicin 

 into the veins, the urine is affected in the same manner as after its 

 introduction by the mouth. Sugar, which, as is well known, is 

 formed in the decomposition of the salicin by synaptase, cannot be 

 recognised in the urine, even when as much as 0*943 of a gramme 

 of salicin has been injected into the blood. Ranke also found 

 saligenin in addition to those acids in the urine, but no saliretin. 



The previous observations leave no doubt as to the function of 

 the alkaline carbonates in the blood, and we have already treated 

 circumstantially of carbonate of soda in the first volume of the 

 present work (see pp. 436-440) ; we will, therefore, only observe, 

 that these salts are able to maintain their function as agents in the 

 process of combustion for an infinitely long period ; that is to say, 

 an infinite quantity of organic acids and carbo-hydrates may be 

 reduced by one and the same quantity of these salts into carbonic 

 acid and water ; for scarcely is an alkaline carbonate decomposed 

 by a substance of this kind, and deprived of its carbonic acid, 

 before it is reconverted into a carbonate by the combustion of the 

 organic substance ; hence we are able to explain how the propor- 

 tionally small quantity of alkaline carbonates which are present in 



* Op. cit. 



