Federal departments at Washington were, not long ago, almost crippled by the prevalence of typhoid fever among the employees; and the public health service under Surgeon-General Walter Wyman traced more than ten per cent. of the cases to the milk supply. Professor Lafayette B. Mendel of the Sheffield Scientific School of Yale University, told one of the writers of this book that he went to a certain city that had suffered an epidemic of typhoid, and made a map showing each house that had contained a case of typhoid fever. He made a similar map showing the houses where certain milkmen stopped—and the two maps were almost completely identical. It has also been established beyond a doubt that tuberculosis is communicated from the cow to the human being, and in certain sections of the world it is believed that milk from tubercular cows is the chief channel of infection. It has been shown that even if the udder of a cow be healthy, a tubercular cow may give infected milk, and that the presence of a single tubercular cow in a herd may be responsible for the infection of the milk of healthy animals. Several international medical congresses have lately declared that all milk should be boiled in order to kill the germs. [Illustration: PROF. LAFAYETTE B. MENDEL, PH.D., YALE UNIVERSITY, Who has carried on researches in conjunction with Prof. Chittenden.] The United States Department of Agriculture issued in Circular No. 111 of the Bureau of Animal Industry, and in Circular No. 114, the recommendations made by a conference of some twenty of the foremost scientists of the United States, and few more important documents concerning the public health have ever been issued by a government. In brief, these recommendations may be thus stated: Raw milk is highly dangerous. Boiling or pasteurizing kills the disease germs and makes the milk safe without seriously impairing the taste or digestibility. Milk produced under the most ideal conditions, such as “certified” milk, is only relatively safe. Pasteurization, when properly done, makes the milk absolutely safe. Butter, of course, is subject to all the arguments that can be advanced against milk, with the additional one that it is even more subject to infection with germs than milk itself, since the time that elapses between its manufacture and its consumption is usually far longer than the time that elapses between the drawing of milk from the cow and its use. Only butter that is made from sterilized cream should be used.