In view of the fact that a determination of the relative frequency with which bovine tuberculosis occurs in children of the same community has a very definite bearing upon the nature of the milk supply of that community, and also that, in some instances, the figures of other investigators have been somewhat too small to deduce final percentages of bovine infection in children, a study of the subject was undertaken in these laboratories. It was our chief object to ascertain the type of infection in each case, rather than to attempt to discuss at any length the morphologic and cultural characteristics of tubercle bacilli from bovine and human sources.
Following the discovery by Theobald Smith,1 in 1898, that two distinct types of tubercle bacilli could be recovered from tuberculous lesions in man, one of which was also pathogenic for cattle, and thus designated "bovine," and the other pathogenic only