PRODUCTS OF MILK. 153 



sometimes used, but the cheese of this country is made almost 

 entirely from cows' milk. Formerly, the cheese was made in 

 the private dairies, but now principally in factories, to which 

 the milk is drawn. The cheese usually made here in the 

 factories is what is known as Cheddar cheese. It is more 

 properly called American Cheddar, or Canadian Cheddar. 



The fat, as we already know, is simply floating in the milk 

 in fine particles, but the casein is held in solution. To get it 

 out of the milk it must be changed to an insoluble form. 

 Rennet is the substance used for this purpose. This is an 

 extract obtained from calves' stomachs. If a little rennet is 

 dropped into a glass of milk, the casein will at once begin to 

 appear as a flaky, curdy substance with the fat entangled in it, 

 and the water may be poured off, leaving behind the casein 

 and fat. In the factory, the milk is strained and run into large 

 vats that have a larger vessel or jacket around them for holding 

 water or steam. By means of this jacket the milk can be 

 cooled or warmed, as the maker desires. The rennet is added, 

 and at once curdling begins ; the proper heat is obtained by 

 hot water or steam, and the curdy milk begins to " ripen." 

 Gradually, by working, the flakes or grains of curd increase in 

 size, and when the proper time comes the water is run off. 

 This water or whey carries away the sugar of the milk and 

 most of the ash material ; little or none of the fat should float 

 away on it if the cheese-making has been properly done. The 

 curd is heaped up and allowed to drain, when it appears as a 

 crumbled mass. Some salt is added and mixed with it ; then 

 it is run through the mill, and is ready for putting up in pack- 

 ages. These packages are pressed out and bandages are put 

 on them, when they are taken to the curing room. The curing 

 of the cheese is a very important part of the making. The 

 room is kept at a warm temperature, and various ferments 

 work in the cheese, causing changes that add much to the 

 flavor and lood value of the cheese. The fresh, or "green," 



