I. Directly from the point, of injury. This is true in infected wounds open to the surface, skin glanders (farcy), black-leg, surface anthrax, exanthemata in man and animals (scarlet fever (?), measles (?), smallpox; hog erysipelas, foot-and-mouth disease): also in case of disease of mucous membranes continuous with the skin--from nasal discharges (glanders), saliva (foot-and-mouth disease), material coughed or sneezed out (tuberculosis, influenza, pneumonias), urethral and vaginal discharges (gonorrhea and syphilis in man, contagious abortion and dourine in animals), intestinal discharges (typhoid fever, “choleras,” “dysenteries,” anthrax, tuberculosis, Johne’s disease). Material from nose, mouth and lungs may be swallowed and the organisms passed out through the intestines. II. Indirectly through the secretions and the excretions where the internal organs are involved. The _saliva_ of rabid animals contains the ultramicroscopic virus of rabies (the sympathetic ganglia within the salivary glands, and pancreas also, are affected in this disease as well as the cells of the central nervous system). The _gall-bladder_ in man is known to harbor colon and typhoid bacilli, as that of hog-cholera hogs does the virus of this disease. It may harbor analogous organisms in other animals, though such knowledge is scanty. The _kidneys_ have been shown experimentally to excrete certain organisms introduced into the circulation within a few minutes (micrococci, colon and typhoid bacilli, anthrax). Typhoid bacilli occur in the urine of typhoid-fever patients in about 25 per cent. of all cases and the urine of hogs with hog cholera is highly virulent. Most observers are of the opinion, however, that under natural conditions the kidneys do not excrete bacteria unless they themselves are infected. The _milk_ both of tuberculous cattle and tuberculous women has been shown to contain tubercle bacilli _even when the mammary glands are not involved_. Doubtless such bacteria are carried through the walls of the secreting tubules or of the smaller ducts by phagocytes and are then set free in the milk. SPECIFICITY OF LOCATION OF INFECTIVE ORGANISMS.