PRODUCTION OF HIPPURIC ACID. 143 



whether that compound of proteine be derived from 

 the food or from the tissues of the body. 



47. It has very lately been stated by A. Ure, that 

 benzoic acid, when administered internally, appears in 

 the urine in the form of hippuric acid. 



Should this observation be confirmed,* it will ac- 

 quire great physiological significance, since it would 

 plainly prove, that the act of transformation of the tis- 

 sues in the animal body, under the influence of certain 

 matters taken in the food, assumes a new form with re- 

 spect to the products which are its result ; for hippuric 

 acid contains the elements of lactate of urea, with the 

 addition of those of benzoic acid : 



1 at. urea . . . . C 2 N 2 H 4 O 2 \ ( 



\ 2 at crystallized hippuric acid 



1 at. lactic acid . C 6 H 4 O v = } 



2 at. benzoic acid COR H 1A ( 



C 36 N 2 H 18 O 12 



48. If we consider the act of transformation of the 

 tissues in the herbivora, as we have done in the car- 

 nivora, then the blood of the former must yield, as 

 the last products of the metamorphosis, from all the 

 organs taken together, choleic acid, uric acid, and am- 

 monia (see p. 129) ; and, if we ascribe to the uric acid 

 an action similar to that of the benzoic acid in Ure's 

 observation, such, namely, that the further transfor- 

 mation, owing to the presence of this acid, assumes 

 another form, the elements of the uric acid being incor- 



* The analysis of the crystals deposited from the urine on the ad- 

 dition of muriatic acid has not been performed. Besides, the state- 

 ment of A. Ure, that hippuric acid, dissolved in nitric acid, is red- 

 dened by ammonia, is erroneous, and shows, that the crystals he ob- 

 tained must have contained uric acid. L. 



