Behring announced in 1903 that pulmonary tuberculosis could be induced from intestinal infection and that infants often become tuberculous from the milk fed to them. Since then there have been many investigations of the occurrence of tubercle bacilli in milk. The milk of tuberculous cows is of most importance in such investigations, but the milk of tuberculous women is also worthy of consideration. The demonstration of tubercle bacilli in human milk and the production of tuberculosis in animals with such milk would point out a possible means of direct transmission of the disease from mother to child. Early life is the period when individuals are most susceptible to tuberculosis, and every possible avenue of infection of children should be investigated and safeguarded if possible.
The available statistics regarding the bacteriology of human milk are much less than those of cow's milk, and the literature reveals a lack of concerted conclusions.