IOO 
Journal of Agricultural Research 
Vol. I, No. 2 
of the country as well as of the horses and the fact that many horse 
owners would try to conceal from the inspectors animals which they 
knew to be affected with the disease. In 1906 the last suspicious cases 
of dourine were destroyed in South Dakota. 
In the meantime, during the year 1903, dourine was reported in Van 
Buren County, Iowa, and successful steps were immediately taken to 
stamp it out. No connection could be established between this outbreak 
and that in Nebraska, but it was quite definitely determined that an 
imported Percheron stallion purchased by a company of farmers was 
responsible for its appearance. 
Another outbreak of dourine was discovered in Taylor County, Iowa, 
in 1911. The diseased animals, together with all exposed stallions and 
mares, were immediately quarantined by the State. Those showing 
lesions of the disease and those exposed horses that reacted to the 
complement-fixation test were purchased by the Government and 
destroyed. It is now believed that the infection is entirely eradicated 
from Iowa. The source from which this center of infection was derived 
is only a matter of conjecture, but there is apparently no connection 
between this and any of the previous outbreaks. No authentic informa¬ 
tion as to the origin of the outbreak was discovered, but all cases lead 
back to a Percheron stallion which was imported in 1909 and brought 
direct to Tenox, Iowa. 
Early in July, 1912, the State Veterinarian of Montana reported several 
suspicious cases of dourine in eastern Montana and forwarded blood 
sera from the suspected animals for the complement-fixation test. 
All but one sample gave positive results, thus establishing a new center 
of infection of dourine. From present indications this outbreak appears 
to be more extensive than any of the previous outbreaks, involving also 
two Indian reservations in North Dakota and South Dakota; but a force 
of 12 Federal veterinarians assisted by State representatives is at work 
on the disease, and the infection is well under control. 
SEARCH FOR A METHOD OF DIAGNOSIS 
The difficulty of diagnosing chronic and latent forms of dourine is 
generally recognized, and owing to this fact the control and eradication 
of this disease in horses has been of slow progress and sometimes in¬ 
effective. In such outbreaks it has been the custom to trace the disease 
as far as possible to its origin and then to keep under observation all 
mares and stallions which directly or indirectly have been exposed to 
the disease. At the same time animals which show clinical evidences of 
the affection are destroyed without delay. By this means several of 
the outbreaks which have occurred in the United States have been 
checked and eradicated. 
The attempt to make a microscopical demonstration of the Trypano¬ 
soma equiperdum in affected horses is very frequently unsuccessful, 
