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 serwn 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 varving from a few weeks to 
several months,” 
