THE DAIRY. 275 



muks, and other Eastern Asiatics, still make considerable 

 use of the milk of their numerous Mares. 



The milk of the Ass possesses nearly the same properties 

 as that of the Mare, but it contains still less of oil and 

 the matter of cheese. It has been used from early times as 

 a medicament. It is sweet and wholesome, and, from the 

 small quantity of oil which it contains, it is the most easily 

 assimilated by the digestive organs of any kind of milk. The 

 butter which may be obtained from it by long agitation, is 

 soft and insipid, and possesses the property of mixing again 

 with the whey. 



Milk, like all the secretions of the animal body, is a very 

 compound substance. It consists of about 90 per cent, of 

 water, holding in solution and suspension the substances 

 which enter into its composition. These are, 1st, The matter 

 of butter, diffused in myriads of globules throughout the 

 fluid ; 2d, Caseine, or the matter of cheese, which is held 

 partly in solution, and partly in suspension ; 3d, Lactine,-or 

 the sugar of milk ; kth, An animal extract, like that yielded 

 by flesh, various soluble salts, and, in some cases, a quantity 

 of free acid. 



When milk is suffered to remain at rest, it separates 

 slowly into two parts. The lighter globules of oil rise to 

 the surface, carrying with them a portion of the caseous 

 matter and serum, and forming the unctuous coat termed 

 cream. The rising of the cream is favoured by employing 

 shallow vessels, and the separation continues for twenty-four 

 hours or more, according to the kind of milk, and the tem- 

 perature of the air. The entire oil does not separate, but a 

 portion of it remains suspended in the liquid. When the 

 cream is removed, the remaining liquid is still opaque, is of 

 a bluish-white colour, and has had its density increased by 

 the removal of the lighter globules. This substance, in com- 

 mon language termed Skimmilk, is perfectly nutritive, con- 

 taining nearly all the caseous and saccharine principles, with 

 a certain portion of the butyraceous. 



