Sources, Pathways and Prevention of Infection in Tuberculosis *

DURING the present century there has been a rapid decline in most of the common infectious diseases in Great Britain. Measles and whooping-cough, almost alone, have not shared in this decline, and have so far resisted efforts at control, while poliomyelitis, for many years prevalent in Scandinavia, U.S.A., and Australia, has come to our shores to offer us a further challenge. For much of the decline in the other infectious diseases, medical research and the public health services