332 BUILDINGS, SANITATION, AND DISEASES 



allowed to run with the sick animals along with a number 

 of untreated animals, which served as controls, and the 

 success following vaccination can therefore be attributed 

 to the action of the serum. In the herds where hog chol- 

 era appeared subsequent to treatment, all of the vaccinated 

 hogs remained well, while more than 65 per cent of the 

 checks (untreated hogs) died. In the herds which had been 

 exposed, but were apparently well at the time of the treat- 

 ment, 4 per cent of the treated animals died, while approx- 

 imately 90 per cent of the checks succumbed. In the herds 

 where disease existed at the time of treatment, and where 

 we did not anticipate very great success, 13 per cent of the 

 treated animals were lost, whereas 75 per cent of the checks 

 died. 



" These successful field trials, confirming as they did 

 numerous tests carried out under experimental conditions, have 

 convinced us of the efficiency of this method of dealing with 

 hog cholera, and, though improvements will undoubtedly be 

 made in many of the details of producing the serum, the method 

 is believed to be now in such condition as to make the practical 

 use of it entirely feasible." 



This plan of combating hog cholera to be successful must 

 be carried out under the direction of skilled veterinarians, and 

 hence little can be accomplished unless the State comes to the 

 aid of the farmer, supplies the serum at cost, and provides 

 veterinarians to make the injections and to supervise the 

 work. 



Three Methods of Vaccinating. (Kansas Bulletin 182.) 

 (1) " The first method is to use the serum alone. In this 

 method there is simply injected into the tissues of the hog a 

 dose of the anti-hog-cholera serum, which makes the hog im- 

 mune against cholera for a time varying from a few weeks to 

 several months." 



