Fig. 21 —Germs which grow in milk and make it sour.

When Milk is a Poison.—In New York, Cincinnati, and Chicago it has been noticed for many years that large numbers of babies become sick in warm weather and many of them die. The doctors learned that most of the babies taken sick were being fed on cows' milk because their own mothers did not have enough for them. It was then found that the sick babies had been using milk from dairies where the stables were dirty, the cows soiled, and the hands of the milkers unclean. On this account much dirt got into the milk.

Babies fed on clean milk from clean cows kept in clean stables remained strong and well. By much study the doctors learned that dirty milk is poisonous milk. The poison is made by the germs or bacteria living by the millions in unclean stables and in milk buckets not well washed in boiling water. Dirty milk becomes most poisonous in hot weather because warmth makes the germs grow very fast and become so numerous that millions are present in a teaspoonful of milk.

Keeping Milk Clean.—During one week of hot weather in Cincinnati, over a hundred babies were poisoned with dirty milk. In the same week twice this number were made sick by unclean milk in Philadelphia. During the hot part of the year in our country bad milk kills more than a half dozen babies every hour of the day and night.

The only way to have milk clean is to have clean stables with clean cows, milked by clean hands, and the milk handled in clean pails, cans, and bottles which have been scalded after being washed. The milk must then be kept cold until used, so that the germs will not grow in it.

Saving the Baby from Bad Milk.—If possible, milk should be bought for the baby in bottles sealed with a pasteboard lid. If milk turns sour the same day it is delivered, it is not fit for the baby to take. Heating it makes most milk safer for use. The heating of milk to kill most of the germs is pasteurizing it. It should be kept very hot for about fifteen minutes, but should not be allowed to boil. It should be cooled by placing the vessel on ice or in cold water.

The baby's bottle and nipple should be washed in cold water and then well scalded immediately after being used. The bottle, the nipple, and the milk should be kept away from flies and dust. One fly has been known to carry on its body more germs than there are leaves on a large tree.

Fig. 22 —Plan of the prison at Easton, Pa. The crosses show into which cells the flies brought typhoid germs from the sewer and made the prisoners sick with fever.