532 LIQUID PARTS OF ANIMALS. 



lantois of the cow ; but it is more probable that in their analysis 

 the two liquors had been mixed together. 



The liquor of the allantois of the cow is transparent, has a 

 fawn-yellow colour, and a taste slightly bitter and saline. It 

 reddened litmus-paper, and had a specific gravity of 1-0072. 

 When evaporated in a porcelain basin, a brownish pellicle form- 

 ed on its surface, and precipitated in flocks. This substance 

 possessed the following properties : 



It was insoluble in water, alcohol, and diluted acids. It dis- 

 solved readily in alkalies. When ignited it blackened, swelled 

 up, and emitted the odour of burning horn. When incinerated 

 it left a grayish ash composed of phosphates of lime and magne- 

 sia. These characters show that the coagulated matter was al- 

 bumen. 



When the liquid was evaporated to the tenth part of its ori- 

 ginal volume, and left in a cool place for twelve hours, it did 

 not deposit crystals. Being now treated with boiling alcohol, it 

 was separated into two portions : the one brown and viscid did 

 not dissolve ; while the other, which was brownish-yellow, dis- 

 solved in the alcohol. 



When the alcoholic solution was evaporated it left a yellowish- 

 brown acid matter, having the smell and taste of beef-tea. 

 Being left at rest for twenty-four hours confused crystals were 

 deposited, which were white, and had a pearly lustre, and which 

 were easily freed from the colouring matter by washing them in 

 cold water. These crystals constituted the substance called am- 

 niotic acid by Vauquelin and Buniva. The name was changed 

 to allantoic acid by Lassaigne, and to allantoin by Wohler and 

 Liebig, because they did not find it to possess acid characters.* 

 The alcoholic extract from which the allantoin had been sepa- 

 rated still reddened litmus-paper. It had a deep-brown colour, 

 and a smell and taste similar to that of the juice of roasted meat. 

 Lassaigne considered it as a mixture of osmazome and lactic acid. 

 When calcined in a crucible it left a grayish-white ash, partly 

 soluble in water. The liquid being evaporated gave crystals 

 of common salt mixed with a little carbonate of soda. The por- 

 tion of the ashes insoluble in water was phosphate of lime. Be- 

 sides these constituents the portion dissolved in alcohol contained 

 some sal-ammoniac. 



* The properties of this substance have been described in the Chemistry of 

 Vegetable Bodies, p. 212. 



