CIIAPTEK XXVIII 

 DISINFECTION 



In the discussion of various diseases, it has been shown 

 that there are a number of ways by which the causal or- 

 ganisms are eliminated from the body of the diseased ani- 

 mal. For each disease the manner of elimination is more 

 or less characteristic. In some it is true that the organisms 

 may he discharged in a number of ways, as in the case of 

 tuberculosis, in which the organisms an- to be found in the 

 sputum, the feces, the milk when the udder is involved, and 

 in the discharge from the genital passages when the repro- 

 ductive organs are affected. In the case of Texas fever the 

 causal organism is able to leave the body only as the blood 

 is drawn, and nmh-r natural conditions the transmission of 

 the organism from animal to animal is due entirely to the 

 bite of a specific insect, one of the cattle ticks. 



It has also been shown that the organisms vary greatly 

 in their resistance to environment. Those that produce 

 spores are, as a rule, resistant to all agencies, and persist 

 for long periods outside the body in the dormant form. 

 The non-spore-forming organisms differ greatly in resist- 

 ance, some resisting certain agencies almost as long as the 

 spore-bearing organisms, while others are so sensitive that 

 the disease produced by them can be transmitted from ani- 

 mal to animal only by the most intimate contact. It is 

 fortunate that none of the important transmissible diseases 

 in man is due to spore-bearing organisms, and but two of 

 the diseases affecting animals, viz., anthrax and blackleg. 

 If it were otherwise, the difficulties in combating the trans- 

 missible diseases would be greatly increased. 



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