234 PATHOGENIC BACTERIA OUTSIDE THE BODY 



festly it would be futile to attempt to prevent or eradicate 

 such diseases by attacking the organism in its natural 

 habitat. Clostridium hotulinum, which causes a type of 

 food poisoning in man, does not even multiply in the body, 

 but the disease symptoms are due to a soluble toxin which 

 is produced during its growth outside the body. 



(6) Organisms like the bacterium of anthrax and the 

 bacillus of black-leg from their local occurrence seem to be 

 distributed from animals infected, though capable of a 

 saprophytic existence outside the body for years. These 

 can no more be attacked during their saprophytic existence 

 than those just mentioned. Doubtless in warm seasons of 

 the year and in the tropics other organisms pathogenic to 

 animals may live and multiply in water or in damp soil 

 where conditions are favorable, just as the cholera organism 

 in India and occasionally the typhoid bacillus in temperate 

 climates do. 



(c) Most pathogenic organisms, however, when they are 

 thrown off from the bodies of animals, remain quiescent, do 

 not multiply, in fact always tend to die out from lack of all 

 that is implied in a "favorable environment," food, moisture, 

 temperature, light, etc. Disinfection is sometimes effective 

 in this class of diseases in preventing new cases. 



II. A. (a) The most common infectious diseases of 

 animals are transmitted more or less directly from other 

 animals of the same species. Human beings get nearly all 

 their diseases from other human beings who are sick; horses, 

 from other horses; cattle, from other cattle; swine, from 

 swine, etc. Occasionally transmission from one species to 

 another occurs. Tuberculosis of swine most frequently 

 results from feeding them milk of tuberculous cattle or from 

 their eating the droppings of such cattle. Swine may also 

 contract avian (bird) tuberculosis from chickens. Human 

 beings occasionally contract anthrax from wool, hair and 

 hides of animals dead of the disease or from postmortems 

 on such animals; glanders from horses; tuberculosis (in 

 children) from tuberculous milk; bubonic plague from 

 rats; tularemia from rabbits and other rodents; rabies 

 practically always from the bites of dogs and other rabid 



