We started the study of the fate of children in tuberculous homes on Dec. 15, 1926. In 1927, we began to vaccinate some of the children with the attenuated living bovine strain of Calmette, called B C G. In 1931, at the request of Dr. E. R. Baldwin, we added to our procedure the use of heat-killed human tubercle bacilli for an additional small group of children. Up to the present we have administered B C G orally (to new-born children) and subcutaneously or intradermally (to children a few months of age). At first, to study the effects of the vaccine, we vaccinated a few older children by injection. The heat-killed vaccine was given subcutaneously or intramuscularly.
The indications for vaccination were: 1. The child came from a home in which some one had tuberculosis. 2. The tuberculin test, roentgenograms of the chest and physical examination gave negative results before