BULLETIN 584:, U. S. DEPARTMENT OF AGRICULTURE. 
Table 1. — Number of infected farms in counties where experimental work icas 
carried on, 1913-1916. 
State. 
County. 
Farms infected. 
1913 1 
1914 
1915 
Decatur 
764 
92 
446 
324 
130 
302 
278 
157 
96 
616 
324 
420 
269 
517 
250 
Twin Falls 
103 
Indiana 
247 
Do 
Montgomery 
Clay 
370 
393 
Iowa 
32 
Do 
Dallas 
324 
82 
Kansas 
48 
Kentucky 
Henderson 
163 
Michigan 
Branch 
19 
Minnesota 
Renville 
74 
Pettis .. 
211 
281 
Nebraska 
86 
South Dakota 
Davison 
116 
Tennessee 
462 
1 Only 3 experimental counties in 1913. 
It is unfortunate that the data contained in this table do not cover 
a greater period of time and that similar information can not be fur- 
nished for a number of counties immediately surrounding each ex- 
perimental county. Nevertheless considerable information is afforded 
by the table in its present condition. 
For the purposes of analysis it will be sufficient to consider the 
records of the three original counties. The table shows that with re- 
spect to prevalence of cholera these counties are not in agreement, 
for while the number of outbreaks steadily declined in Dallas County, 
Iowa, they increased slightly in Montgomery County, Ind., in 1915, 
while in Pettis County, Mo., though somewhat reduced in 1915, they 
yet exceeded the record of 1913. YVTiat is the explanation of these 
figures and how are these differences to be accounted for ? 
A separate consideration of each of these counties is necessary to 
obtain an answer to these questions. As stated above, no figures are 
available on the number of outbreaks in surrounding counties during 
the same period. However, some data relative to total losses from 
cholera in neighboring territory have been obtained, and this informa- 
tion enables us better to understand the records of these three experi- 
mental counties. 
With reference to Dallas County, the table shows that the disease 
was most prevalent in 1913, slightly reduced in 1914, and greatly re- 
duced in 1915. It is a fact that hog cholera in the State of Iowa as 
a whole followed somewhat the same course,' being much less in extent 
in 1915 than in either of the two preceding years. Furthermore; a 
carefully prepared estimate, following personal investigations of the 
losses of hogs in 1913, 1914, and 1915 in seven neighboring counties 
where no organized fight against cholera was being carried on, shows 
the same progressive decrease that occurred in Dallas County. The 
