CONTROL OF HOG CHOLERA. 5 
as all new stock could be immunized before being brought upon the 
infected premises, while the immunization of neighboring herds 
probably would lessen greatly the chances of spread. All things con- 
sidered, then, this plan seemed to be one that would enlist the coop- 
eration of farmers and at the same time do much toward reducing the 
losses from the disease. 
On July 1, 1913, the Congress of the United States appropriated 
the sum of $75,000 to be used for the purpose of " demonstrating 
the best method of preventing and eradicating hog cholera," and 
later, on February 23, 1914, supplemented this with an additional 
appropriation to permit work on a much larger scale. With these 
funds extensive field experiments have been carried on, and it is the 
purpose of this paper to discuss the results of these experiments, both 
with respect to their bearing upon the broad questions of control and 
upon certain important, though minor, questions that are involved. 
FIELD EXPERIMENTS LOOKING TO THE CONTROL OF 
HOG CHOLERA. 
As stated above, the first appropriation for field work became 
available on July 1, 1913, and the work itself was begun at that time. 
The plan was to try out in several small areas the procedure sug- 
gested and outlined in the preceding section. A single county was 
adopted as the unit area for the experiments, and during the first 
year work was carried on in three counties, namely, Dallas County, 
Iowa, Montgomery County, Ind., and Pettis County, Mo. Later, 
in the spring of 1914, when more money had become available, other 
counties in other States were added, so that in the summer of 1914 
active work was being carried on in 14 counties in 12 different States. 
In each county the United States Department of Agriculture 
placed three veterinary inspectors and one clerk, previous arrange- 
ments having been made with the State agricultural college and 
with the State veterinarian or live-stock sanitary board for cooper- 
ation in educational work on the one hand and in the enforcement 
of the necessary sanitary regulations on the other. 
At the beginning, in each county steps were taken with the aid 
of the State agricultural college to inform farmers of the objects 
sought, of the characteristics of the disease and channels which serve 
to convey it, and of the importance of promptly reporting outbreaks. 
A census of hogs and of losses from diseases was taken, and the 
existing centers of infection were located as far as possible. To 
obtain the cooperation of the farmers, which is an essential to suc- 
cess in work of this nature, organizations of farmers were formed 
in each township, consisting of one leader and eight district repre- 
