CONTROL OF HOG CHOLERA. v6 
antine against infected farms. The properties and limitations of 
anti-hog-cholera serum were also fully discussed. 
From what has been said it will be seen that these experiments for 
the study of the control of hog cholera partook only to a small degree 
of the characteristics of the usual control methods. Strict sanitary 
police measures were replaced by organization and education, and 
torce was replaced by argument and explanation. Now, after three 
years of effort, the original indifference to the work has, for the most 
part, been replaced by genuine interest and willingness to cooperate 
on the part of farmers. It is interesting to consider the results. 
RESULTS OF FIELD EXPERIMENTS. 
The results of this work may be considered from four different 
viewpoints: (1) Cost of the work; (2) prevalence of the disease; (3) 
losses from cholera; and (4) gondition of the hog industry. 
COST OF THE WORK. 
The principal item of expense in connection with this work is the 
salary list of field inspectors. Next in importance is the cost of the 
serum, and to these two items must be added charges for trans- 
portation, equipment, and general supervision. The cost per county 
to the Federal Government has averaged a little less than $9,000 
a year. In most cases the amount expended by the States has been 
small, and it is safe to say that the total expenditures on the average 
have not exceeded $10,000 per county per annum. 
PREVALENCE OF THE DISEASE. 
The actual effect of this work upon the prevalence of hog cholera 
is difficult to determine. As shown by figure 1, the disease, consider- 
ing the country as a whole, varies in prevalence from year to year. 
Furthermore, these experiments began at a time (1918) when hog 
cholera had almost reached the pinnacle of one of the periodic waves 
of prevalence. During 1914 there was a decrease in some sections 
and in 1915 the disease was on the decline in the country as a whole, 
though it is true that in some localities it did not materially abate. 
Bearing these facts in mind, we may consider the number of out- 
breaks (that is, individual farms upon which the disease appeared) 
that occurred in the several areas during the experimental period, as 
shown in Table 1. 
