CHAPTER XVIII. 

 DISINFECTION. 



It has been seen that the disease-producing bacteria 

 pass from the bodies of living and dead animals in a 

 number of ways, as in the material coughed up from the 

 lungs, as in tuberculosis ; in the manure, as in hog 

 cholera; in the milk, as in tuberculosis; in the contents 

 of abscesses and carbuncles, as in anthrax, black leg, and 

 pyogenic troubles, and in the discharges from the nostrils, 

 as in glanders. The bacteria thrown off from the bodies 

 of the diseased animal contaminate the stables, yards, 

 and fields, and from these contaminated places and ob- 

 jects often enter the bodies of healthy animals thus serv- 

 ing to perpetuate the disease in the herd. 



If the farmer is to stop the spread of transmissible dis- 

 ease, he must destroy in some effective way the bacteria 

 that have been thrown off from the bodies of diseased 

 animals. In short he must disinfect the barns and 

 stables, and as far as is possible the yards and fields. 



In the destruction of the pathogenic bacteria consider- 

 ation must first be given to the resistance of the organism 

 it is desired to destroy. For this purpose the various 

 disease-producing bacteria may be divided into two 

 classes; those that ^produce spores and those that do not 

 form these resistent bodies. The former class of bac- 

 teria are very difficult to kill, the latter are easily de- 

 stroyed. Fortunately, but two of the important dis- 

 eases of animals are produced by spore-bearing bacteria. 



