240 HOG CHOLERA 



demonstrated that the disease can be kept down in 

 individual counties, but the expense involved was 

 so great as to forbid use of the plan on a large 

 scale. Area work in the eradication of hog chol- 

 era is, we believe, wrong in its conception as long 

 as the virus continually invades the selected terri- 

 tory from without through the three channels that 

 have just been indicated. 



No successful standardized plan for the control 

 of hog cholera has yet appeared. Killing infected 

 and exposed animals and indemnifying the owners 

 has been tried in England and Canada but results 

 have not been such as to recommend wide applica- 

 tion of the plan. Immunizing all hogs against 

 cholera was once enthusiastically recommended, 

 but we doubt if there can be found to-day an ex- 

 perienced man who considers this method feasible. 

 It would involve the principle of forcing owners 

 to vaccinate, the expense would be prohibitive, 

 and the trained men necessary to carry it out do 

 not exist. 



In our appraisal of the cooperative forces 

 which can be brought to bear immediately in hog 

 cholera eradication we must include the swine 

 breeder, the practicing veterinarian, the official 

 veterinarian and the serum producer. 



The breeder should be acquainted with the 

 methods by which hog cholera is spread so as to 

 be able to protect his herd against extraneous 



