226 ENTRANCE OF PATHOGENIC ORGANISMS 



PATHS OF ELIMINATION OF PATHOGENIC MICRO- 

 ORGANISMS. 



I. Directly from the point of injury. This is true in 

 infected wounds open to th6 surface, skin glanders (farcy), 

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

 [scariet fever (?), measles (?), smallpox; hog erysipelas, foot- 

 and-mouth disease]. Also in case of disease of mucous mem- 

 branes continuous with the skin — from nasal discharges 

 (glanders), saliva (foot-and-mouth disease), material coughed 

 or sneezed out (tuberculosis, influenza, pneumonias), ure- 

 thral and vaginal discharges (gonorrhea and syphilis in man, 

 contagious abortion and dourine in animals), intestinal dis- 

 charges (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 ultra-microscopic 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 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 knowl- 

 edge is scanty. The kidneys have been shown experimen- 

 tally to excrete certain organisms introduced into the circu- 

 lation within a few minutes (micrococci, colon and typhoid 

 bacUli, 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. 



