88 THE INVISIBLE WORLD 



bution to the consumer, all danger is avoided. If 

 he does not, as soon as the milk is received in the 

 home, it should there be heated to 165 degrees, 

 bottled, corked with sterilized cotton, and kept in 

 a cool place. It will then keep sweet for a long 

 time, and its use will be safe and wholesome. 



The natural process of souring milk is a decided 

 benefit. It separates the milk into its four ele- 

 ments, and enables the owner to use each part to 

 best advantage. Every hundred quarts of milk 

 contain eighty quarts of water, five of cheese, four 

 of sugar, and three of butter. The microbes con- 

 sume the sugar and convert it into lactic acid. 

 The acid unites with the water, and thus pre- 

 cipitates the cheesy element, while the butter rises 

 to the surface in the shape of cream. The cream is 

 converted into butter, while all the other parts are 

 used as feed for calves, swine, and so on. , 



It need not be said that the separator now usu- 

 ally takes the place of the microbes, separating 

 the cream from the milk as soon as it comes from 

 the cow. But the practical result in each case is 

 the same. 



Every one is naturally interested in milk. 

 There is a time in every one's life when he lives 

 wholly on milk. It is the natural food for all young 

 children. It is their best, if not their only, food. 

 It is the natural and only food of all the young 

 of the lower mammals 1 as well. Milk contains more 

 nourishing properties than any other kind of food. 

 The young, therefore, of all mammals, including 



