I have now given you a general idea of the origin and spread of the tubercular infections ending disastrously. This brings us at once to certain practical points in dietetic hygiene which, though never entirely neglected, are now brought into prominence. It is unnecessary for me to further emphasize the necessity, in infant feeding, to insist under all circumstances on milk absolutely free from tubercle bacilli; nor, what is equally obvious, that it is absolutely necessary to keep coughing consumptives away from infants. But I should like to observe that not only infants but also older persons should be protected against the possibility of infection, if we have any reason to fear that the alimentary tract is anywhere deficient in its protective epithelial covering. I have already pointed out the importance of the exanthemata in this respect, and I need only remind you of the many other disturbances associated with the shedding of epithelium, disturbances due to catching cold, to indigestion, or the after-effects of certain diseases associated with intestinal ulceration, etc. There is one other condition which I must not fail to mention, namely, the temporary exacerbations of a tubercular process, in which one cannot be too careful in ordering the diet. For that large class of individuals threatened with consumption, I believe we have a valuable healing agent in the dietetic therapy made prominent during the past decade, especially by von Leyden and his pupils. In the same sense we must regard the temporary residence of tuberculous individuals in sanitaria as most valuable, for even if the lesions do not heal there, the progressive downward course of the disease is checked and the patients learn for the rest of their lives to appreciate what will benefit and what will harm them. In many cases, therefore, these sanitaria will prove themselves homes for the prevention of consumption, even if they are not homes for the cure of tuberculosis. My own efforts in the field of tubercular therapeutics do not, to be sure, concern themselves with sanitarium treatment. _Their last aim is to make all homes for the prevention of consumption, all sanitaria, etc., unnecessary by means of a protective agent similar to that by which Jenner made smallpox pest-houses unnecessary._ Institutions for persons bodily wrecked are like those for persons morally wrecked; they are products of our civilization, but not desirable products. At best they are necessary evils. OBSERVATIONS CONCERNING THE STUDY OF PHTHISIOGENESIS IN MAN AND IN ANIMALS. 1. It is possible in experiments on guinea-pigs to produce pulmonary phthisis by infecting these animals from the oral cavity in such a manner that every direct infection of the lungs (alveolar infection through the trachea = aerogenous infection of the lung) is excluded. (_a_) Infection through the parenchyma of the tongue. (_b_) Feeding of tubercle bacilli with milk.