VITALITY OF HOG-CHOLERA VIRUS 97 



and other refuse and thoroughly destroying same by saturating 

 with kerosene and burning. 



Liquor Cresolis. — Following this the pens should be thoroughly 

 sprayed with the liquor cresolis compound above described and 

 then sprinkled with chlorid of lime. Sheds should be cleaned with 

 especial thoroughness, whitewashed, and sprayed with the cresol 

 compound. 



Old insanitary sheds should be torn down or burned, and re- 

 placed by modern sanitary buildings which admit plenty of light 

 and sunshine. 



Old hog wallows should be drained, the mud at the bottom 

 either removed or thoroughly saturated with disinfectant solution, 

 and allowed to remain exposed to the direct rays of the sun for 

 several weeks. 



New hogs added to the pens should be treated by the serum- 

 simultaneous vaccination method, and thus rendered immune to 

 any infection that may remain. Of this latter method of over- 

 coming the attack of the cholera virus more will be said in the fol- 

 lowing pages. 



Examples of how cholera virus will persist in pens which have 

 once become infected are familiar to all of us, but a few illustra- 

 tions may be of interest. 



As a boy, in western Illinois, I can remember the case of one 

 farmer who resided on an adjoining farm. This man had a large 

 herd of animals one summer which became infected with hog- 

 cholera, and large numbers of them died before the balance had 

 been shipped to market. The pens on this farm were in a particu- 

 larly insanitary condition. The hogs had the run of the cattle 

 feed lots, and there was an inch or more of old corn cobs on the 

 ground over the entire feed lot. These were thoroughly worked 

 up with the mud in the feed lot every time it rained. As a result 

 the virus was thoroughly worked into the soil during the time the 

 outbreak lasted on the farm. 



About three months after the last of these hogs had died the 

 farmer brought in a new drove of nearly 100 hogs, which had been 

 purchased from a herd some miles distant in a vicinity where 

 cholera had not been present for several years. 



Within ten days after the new hogs had been brought in a few of 



