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3Ia7iual of Veterinary 3Iicrohiology . 



accidents — whicli are met with almost every-where — 

 must be present on the surface of the body and even 

 in its interior, upon the various mucous membranes 

 and especially that of the digestive canal. Recently 

 the bacillus of tetanus has been discovered in the 

 fsecal matters of healthy horses. The pneumococ- 

 cus — the pathogenic germ of lobar pnuemonia in 

 man — ^is constantly present in the buccal mucus of 

 nearly all individuals. The skin, the respiratory mu- 

 cous membrane and that of the genitd-urinary pas- 

 sages near the openings communicating "vvith the ex- 

 terior, are likewise contaminated with ubiquitous 

 germs. 



The transmission of a contagious disease through 

 the intermediation of healthy individuals, animals or 

 mankind, shows that pathogenic micro-organisms 

 may be present on or in the body without producing 

 disease. The methods by which infection is produced 

 and the phenomenon of immunity sufficiently explain 

 this peculiarity. 



Infected organism. — The organism attacked by a 

 contagious disease harbors the microbes of the latter 

 in very difierent points according to the nature and 

 localization of that disease. It is desirable, for the 

 ends of a rational prophylaxy, to know the places of 

 election of the germs of the different diseases, and, 

 more especially, the seat of those which, in being 

 eliminated from the economy, are able to contaminate 

 healthy individuals. 



We may meet with these germs in the various 

 secretions flowing to the exterior: in the saliva: 

 rabies; in the ftecal matters: tuberculosis, typhoid 

 fever, cholera, chicken cholera, pneumo-enteritis ; in 



