THE DAIRY 203 



skimmed cream of the same fat content, and is sometimes 

 thickened by the addition of " viscogen," made by mixing 

 2| parts of cane sugar, 1 of quicklime, and 8 of water. About 

 1 oz. of the clear solution will thicken a gallon of cream. 



Skimmed Milk varies in composition according to the more 

 or less complete removal of the fat. 



Skimmed milk from hand-skimming usually contains about 

 06 per cent, of fat, but may contain as much as 2 per cent. 

 Separated milk usually contains from 005 to 0-15 per cent, of 

 fat. In consequence of the removal of fat the percentage 

 amounts of the other constituents are slightly higher than in 

 the original milk. Thus milk of the average quality given on 

 p. 187 might be expected to yield with a good separator 

 skimmed milk of about the following composition : 



Water 90-54 



Fat 0-10 



Sugar 4-94 



Casein 3'11 



Albumin 0'42 



Citric acid 0-10 



Ash 0-79 



100-00 



Skimmed milk contains a valuable amount of food-stuffs, and 

 should be utilised on the farm for feeding pigs or in other 

 ways. Separated milk, though poorer in fat, has the advan- 

 tage of being sweet and of keeping better ; by the addition of 

 cod-liver oil it has proved successful in calf-rearing. 



Butter. — When cream or milk is agitated for some time the 

 fat globules coalesce and butter separates out in irregular 

 masses, which consist of almost continuous fat, very few of the 

 original globules remaining. The spherical globules visible in 

 butter under the microscope consist of minute drops of butter- 

 milk or water enclosed in the fat. 



Churning is a purely mechanical process : the fat globules 

 collide, adhere, and the large, irregular masses thus formed in 



