792 



thus treated will keep nearly as long again as milk not so treat< 

 and all animal odour is removed. \Vhere this appliance is not 

 procurable the milk can be greatly improved by means of passing a 

 current of fresh air through it. 



The specific gravity of ordinary milk is given at 1*031, which 

 means that a vessel holding, say, 1000 pounds of water if filled up 

 with the same quantity of milk, would weigh 31 pounds more. But 

 the various constituents of milk, if separated, differ greatly in their 

 specific gravity, thus the fat is lighter than either milk or water, 

 having only a specific gravity of '930, and thus it is that the fatty 



_ _ PIPETTE 



ACID MEASURE 



Fisj 4. Li-tei-B;ilu-(K-k Milk T 



portion, or cream, rises to the surface when the milk is allowed to 

 remain quirt. 'The fat in milk is in small globules, and they vary 

 greatly in size in different breeds and individual cows. The si/e of 



globules varies from | .' part of an inch in diameter t< 

 and it is this variati n in si/e that makes the cream from some 

 cow's milk rise SO much more quickly than the- cream from others. 



