176 BASIC BODIES. 



Physiological Relations. 



Occurrence. Vauquelin and Buniva thought that they had 

 found allantoine in the Liquor Amnii of a cow, but Lassaigne* 

 proved that it is peculiar to the Liquor Allan toidis. It has 

 recently been found by Wohlerf in considerable quantity, in the 

 urine of young calves. It has as yet been found nowhere else in 

 the animal organism. 



According to Wohler, the allantoine from calves' urine presents 

 the peculiarity that it differs in the character of its crystals from 

 that which is obtained from the allantoic fluid or from uric acid ; 

 the crystals grow together in bundles, and their terminal .surfaces 

 are no longer distinct, while pure allantoine appears in isolated well- 

 formed prisms. This difference, however, only depends on the 

 admixture of a foreign substance, whose quantity is much too 

 minute to produce any appreciable influence on the result of its 

 elementary analysis. By combining it with oxide of silver, and 

 then decomposing the compound, we obtain it in as pure and 

 isolated a state as when we prepare it from the allantoic fluid or 

 from uric acid. 



Origin. That allantoine is a product of the metamorphosis of 

 nitrogenous food or of tissue in the animal organism, is sufficiently 

 obvious from the circumstances under which it occurs, but any 

 nearer indication of the chemical process on which its formation 

 depends is impossible, since we have no idea of its rational com- 

 position. The two following facts may, however, probably 

 indicate the way in which its formation may at some future time 

 be explained : firstly, it only occurs in the urine of the foetus and 

 of recently-born animals, and disappears after the use of vegetable 

 food ; secondly, as has been discovered by Wohler, it occurs in the 

 urine of sucking calves, together with uric acid and urea, but without 

 hippuric acid ; hence the idea suggests itself that allantoine and 

 hippuric acid exclude or stand in the place of one another, which 

 might rather have been expected of uric acid, from which allantoine 

 may be artificially prepared. 



* Ann. de Ch. et de Phys. T. 17, p. 301. 



t Nachrichten der k. Gesellsch. d. Wiss. zuGottingen, 1849. No. 5, S. 61-64 ; 

 [and more fully in Ann. d. Ch. u. Pharm. Bd. 70, S. 229. G. E. D.] 



