MILK. 441 



rest a cream collects on its surface : but by no means in such 

 quantity as in woman's milk. This cream, by very long agitation, 

 yields a butter which is always soft, white, and tasteless ; and 

 what is singular, readily mixes with the butter milk ; but it may 

 be again separated by agitation, while the vessel which contains 

 it is plunged in cold water. Creamed ass's milk is thin, and 

 has an agreeable sweetish taste. Alcohol and acids separate from 

 it a little curd, which has but a small degree of consistence. 

 The serum yields sugar of milk and chloride of calcium.* 



According to the experiments of Stipriaan, Luiscius and 

 Bondt, ass's milk yields at an average 2*9 per cent, of cream, 

 2*3 of casein, and 4*5 of sugar of milk. It undergoes very rea- 

 dily the vinous fermentation.f They found the specific gravity 

 of ass's milk 1'023. 



In 1836, M. Peligot published some interesting experiments on 

 ass's milk. The object which he had in view was, if possible, 

 to discover whether the medicinal properties ascribed to this 

 milk might not be accounted for by some variation in its solid 

 constituents from that of the milk of other animals.:]: Its speci- 

 fic gravity varies from 1*030 to 1*035, being nearly the same as 

 that of cow's milk, yet it contains less solid matter. But cow's 

 milk contains more cream, which counteracts the effect of its so- 

 lid contents. 



The mean composition of ass's milk, according to Peligot, is, 



C Butter, . 1-29 



Solid matters, 9 -53 -J Sugar of milk, 6-29 



(.Casein, . 1-95 

 Water, . 90-47 



9-53 

 100- 



It contains more sugar of milk than cow's milk, and to this he 

 ascribes its medicinal properties. 



It was found that the proportion of solid matter varied ac- 

 cording to the food by which the ass was nourished. The fol- 

 lowing are the results : 



1. An ass fed during a month on carrots yielded a milk com- 

 posed of, 



* Parmentier and Deyeux, Jour, de Phys. xxxvii. 423. 



t Crell's Annalen, 1794, ii. 266. 



\ Ann. de Chim. et de Pbys, Ixii. 432. 



