which is generally much greater in the virus of bovine tuberculosis than in that of human tuberculosis. It also depends on the number of bacilli introduced per stomach, and whether such introduction is single or oft repeated. In the human being months and years may elapse before the infection is followed by any sensitiveness to tuberculin injections in the usual dose. If, then, at the time of puberty, or after an exhausting puerperium, after too great a demand on the milk secretion (especially with insufficient food), after so-called colds and other unfavorable meteorological conditions, after muscular over-exertion, under conditions unfavorable to life, such as improper nourishment, confinement in insufficiently or badly ventilated rooms, etc., if, after any of these, pulmonary disease develops whose tubercular nature we cannot doubt, then we are dealing with the _beginning of consumption_; the _beginning of tubercular lesions_ is much further back; and the first introduction of the disease germs, in other words, the _beginning of the infection_, is far back in earliest infancy. This must be so, for we see many individuals, though subject to the most unfavorable conditions, for example, those confined in unsanitary prisons, wholly escape tuberculosis. The results of all these scientific investigations lead us back to the old folk belief in family tuberculosis and hereditary consumption, with this difference, however, that now we believe the germs of consumption to be transmitted _postgenitally_ from parents, relatives, or house-companions. If a coughing consumptive lives together with a new-born child, especially if cleanliness leaves much to be desired, it is impossible for this child to avoid infection with tubercle bacilli. They are present in the particles of sputum which are scattered about everywhere, and they thus gain access to the mouth and nose of the infant. From there they reach the intestinal mucous membrane, which they penetrate, and so they invade the body juices. Not alone infants, but older persons as well, are endangered in the home of the consumptive. In these, however, there must previously have been pathological changes in the alimentary tract, or an overwhelming dose of the infectious agent, in order to effect an intestinal infection. Pathological changes, accompanied by the shedding of epithelium, occur especially in the exanthemata, and particularly after measles. The laity has long noticed this close relation between measles and tuberculosis. In the infant, the disposition to intestinal tubercular infection is entirely physiological and normal. The healthiest and strongest infant is exposed fully as much as the weak, sickly one, and perhaps more so, for in the latter other parasites are contending for the cells on which they feed.