Other Disease Germs in Milk.--We have already shown how typhoid may be spread through milk. Usually such outbreaks may be traced to a single case of typhoid, often a person who is a "typhoid carrier," _i.e._ one who may not suffer from the effects of the disease, but who carries the germs in his body, spreading them by contact. A recent epidemic of typhoid in New York City was traced to a single typhoid carrier on a farm far from the city. Sometimes the milk cans may be washed in contaminated water or the cows may even get the germs on their udders by wading in a polluted stream. Diphtheria, scarlet fever, and Asiatic cholera are also undoubtedly spread through milk supplies. Milk also plays a very important part in the high death rate from diarrhoeal diseases among young children in warm weather. Why? [Illustration: A diagram to show how typhoid may be spread in a city through an infected milk supply. The black spots in the blocks mean cases of typhoid. _A_, a farm where typhoid exists; the dashes in the streets represent the milk route. _B_ is a second farm which sends part of its milk to _A_; the milk cans from _B_ are washed at farm _A_ and sent back to _B_. A few cases of typhoid appear along _B_'s milk route. How do you account for that?] Grades of Milk in a City Supply.--Milk which comes to a city may be roughly placed in three different classes. The best milk, coming from farms where the highest sanitary standards exist, where the cows are all tubercular tested, where modern appliances for handling and cooling the milk exist, is known as certified or, in New York City, grade A milk. Most of the milk sold, however, is not so pure nor is so much care taken in handling it. Such milk, known in New York as grade B milk, is pasteurized before delivery, and is sold only in bottles. A still lower grade of milk (dipped milk) is sold direct from cans. It is evident that such milk, often exposed to dust and other dirt, is unfit for any purpose except for cooking. It should under no circumstances be used for children. A regulation recently made by the New York City Department of Health states that milk sold "loose" in restaurants, lunch-rooms, soda fountains, and hotels must be pasteurized. Care of a City Milk Supply.--Besides caring for milk in its production on the farm, proper transportation facilities must be provided. Much of the milk used in New York City is forty-eight hours old before it reaches the consumer. During shipment it must be kept in refrigerator cars, and during transit to customers it should be iced. Why? All but the highest grade milk should be pasteurized. Why? Milk should be bottled by machinery if possible so as to insure no personal contact; it should be kept in clean, cool places; and no milk should be sold by dipping from cans. Why is this a method of dispensing impure milk?