166 HOG CHOLEBA 



infectants are of little service, and we must de- 

 pend on natural influences (drying and sunlight) 

 to destroy virus which contaminates the soil. 



Many states have specific regulations governing 

 precautions against interherd spread of hog chol- 

 era, and when these are available and practicable 

 they should be followed. None of the shoats 

 should be removed earlier than thirty days follow- 

 ing disappearance of all sickness from the herd, 

 and previous to their removal, if they are to min- 

 gle with cholera susceptible hogs they should first 

 be dipped or sprayed with 3 per cent compound 

 cresol solution. It is legal in some states, in han- 

 dling a herd of this kind, to remove apparently 

 well animals for immediate slaughter under in- 

 spection, but except in unusual circumstances the 

 practice has little to recommend it. 



If we go back to our original problem and as- 

 sume alterations in the conditions there outlined, 

 corresponding changes in the plan of handling will 

 suggest themselves, and the reasons for these 

 changes will appear. If hogs are closely confined 

 and the herd is badly infected, serum alone is indi- 

 cated, because natural infection will take place 

 and produce permanent immunity in all that sur- 

 vive ; if they are found under conditions that sug- 

 gest low resistance, if they are of exceptional 

 value, or if the owner is skeptical, nervous, or 

 overcritical, plan number three should be recom- 



