Nowadays, in the best dairies, it is required that the barns or sheds in which cows are milked shall have tight walls and roofs and good flooring; that the walls and roofs shall be kept white-washed; and the floor be cleaned and washed before each milking, so that no germs from dust or manure can float into the milk. Then the cows are kept in a clean pasture, or dry, graveled yard, instead of a muddy barnyard; and are either brushed, or washed down with a hose before each milking, so that no dust or dirt will fall from them into the milk. The men who are to milk wash their hands thoroughly with soap and water, and put on clean white canvas or cotton overalls, jackets, and caps. As soon as the milk has been drawn into the pails, it is carried into the milk-room and cooled down to a temperature of about forty-two degrees--that is, about ten degrees above freezing point. This is to prevent the growth of such few germs as may have got into it, in spite of all the care that has been taken. Then the milk is drawn into bottles; and the bottles are tightly capped by a water-proof pasteboard disc, or cover, which is not removed until the milk is brought into the house and poured into the glass, or cup, for use. [Illustration: THE MILKING HOUR AT A MODEL DAIRY] Milk handled like this costs from two to four cents a quart more to produce than when drawn from a cow smeared with manure, in a dark, dirty, strong-smelling barn, by a milker with greasy clothing and dirty hands; and then ladled out into pitchers in the open street, giving all the dust and flies that happen to be in the neighborhood a chance to get into it! But it is doubly worth the extra price, because, besides escaping stomach and bowel troubles, you get more cream and higher food value. There is one-third more food value in clean milk than in dirty milk, because its casein and sugar have not been spoiled and eaten by swarms of bacteria. How great a difference careful cleanliness of this sort can make in milk is shown by the difference in the number of bacteria that the two kinds of milk contain. Ordinary milk bought from the wagons in the open street, or from the cans in the stores, will contain anywhere from _a million_ to a _million and a half_ bacteria to the cubic centimeter (about fifteen drops); and samples have actually been taken and counted, which showed _five_ and _six millions_. [Illustration: MILKING BY VACUUM PROCESS This method is used in many large dairies to avoid handling the udders or the milk. Its chief drawback is that the long tubes are very difficult to keep clean.]