244 PATHS OF ENTRANCE OF PATHOGENIC ORGANISMS 



black-leg, surface anthrax, exanthemata in man and animals 

 (scarlet fever (?), measles (?), small-pox; 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 pan- 

 creas also, are affected in this disease as well as the cells of 

 the central nervous system). The gaU-bladder in man is 

 known to harbor colon and t^^phoid bacilli, as that of hog 

 cholera hogs does the virus of this disease. It may harbor 

 analogous organisms in other animals, though such knowl- 

 edge is scanty. The kidneys have been shown experimen- 

 tally to excrete certain organisms introduced into the circu- 

 lation within a few minutes (staphylococci, 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 tvheii 

 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. 



