Having thus studied the fate of anthrax bacilli introduced into the stomach of new-born and adult guinea-pigs, I now turned to a similar study of tubercle bacilli. Together with Dr. Römer I studied the behavior of guinea-pigs toward a definitely weighed quantity of tubercle bacilli given in _one single feeding_. And here also, as in the case of anthrax bacilli, it was found that when the tubercle bacilli could be demonstrated microscopically nowhere else in the alimentary tract, they were often present in the cæcum. After a single feeding of a small quantity of tubercle bacilli, only the new-born or the few-days-old guinea-pigs became tuberculous. When larger doses were administered it happened that older animals also became tuberculous. At the post-mortem examination of the new-born, a few days later, there were found submiliary thickenings, with tubercle bacilli in the great and the lesser omentum. There were also little nodules at a point on the root of the mesentery, not far from the cæcum. Of especial interest is the further development of this alimentary tuberculosis in the guinea-pigs which survived. In these animals, even while their general health remains good, it is always possible to demonstrate a tuberculosis of the glands of the neck, a type of disease which may be said to correspond to scrofula in man. Not infrequently there is later on developed that type of guinea-pig tuberculosis which has heretofore been regarded as the expression of an inhalation tuberculosis. In the results of all these investigations I see experimental support for the view I have for some time maintained, namely, that the origin of the epidemiological pulmonary tuberculosis in man and that of the epizootic pulmonary tuberculosis in cattle is a primary intestinal infection occurring in very early infancy. In this I leave undecided whether the bacilli gain access to the body through feeding or through inspiration.