370 DOURINE 
edematous and tender, with suppurative or necrotic foci. The 
adjacent lymph glands are enlarged by infiltration or contracted by 
sclerosis. 
In the dog the symptoms and the lesions resemble those in the 
horse. 
Diagnosis. Dourine is diagnosed by the symptoms, lesions, find- 
ing the specific trypanosome and by the complement fixation test. 
The “dollar spots” or cutaneous plaques are quite characteristic in 
northern latitudes. The trypanosome may be found in the urethral 
and vaginal discharges in the early stages of the disease by a careful 
microscopic examination. They are not present in the blood except 
for short periods. In chronic cases they are difficult to find. 
The complement fixation method is reported by Mohler to be very 
satisfactory.* 
It is being used to identify infected horses in districts where the 
disease exists. 
Dourine is to be differentiated from the other forms of trypano- 
soma disease, and also from “benign venereal disease.”’ 
Pearl found a disease simulating dourine caused by filaria. 
Williams describes a benign venereal disease of mares all of which 
had been bred to an imported French draft horse. He states that 
“the margins of the vulva retain their natural color in this disease, 
except at the seat of eruptions, when the color quickly returns. The 
*The method for the Complement Fixation Test for Dourine used and. recommended 
by Mohler, Eichhorn and Buck (see Journ. of Agricultura] Research, November, 1913), 
is as follows: 
“The test proper for the diagnosis of dourine is carried out in a manner similar to 
that practiced for the diagnosis of glanders. 
“The hemolytic system consists of sensitized rabbit serum, serum from a guinea 
pig, and a 5 per cent. suspension of washed sheep corpuscles. 
“The serum to be tested is, of course, inactivated for one-half hour at 56° C. and is 
used in the tests in quantities of 0.15 cc. since it has been found that fixation in this 
quantity is obtained only with sera of horses affected with dourine. Tests to determine 
the smallest quantity of serum of horses having dourine which will give a fixation 
Sa that in several instances even 0.02 cc. of serum was sufficient to give a complete 
xation. 
“The complement from the guinea pig is always titered previous to the test, as it is 
absolutely necessary to use the exact amount of the complement to obtain the best 
results, since a deficiency or an excess of the complement would interfere greatly with 
the reaction.” 
The antigen used consists of the ground-up spleen of rats that have died from surra. 
The spleens are ground with a small amount of salt solution and the suspension thus 
obtained is filtered twice through double gauze into a test tube. The quantity of sus- 
pension from each spleen is made up to 40 cc. by dilution with salt solution. 
The complement fixation for dourine using the spleen of surra infected rats for anti- 
gen isa group reaction. As dourine is the only trypanosomic disease of horses in this 
country, such a group reaction is practically specific for its diagnosis. 
