196 JOHNE’S DISEASE 
this affection. He reported very good results and recommended its 
subcutaneous use as a diagnostic agent. The results from the 
ophthalmic application were not satisfactory. From 4 to 8 ce. of 
avian tuberculin is used. The reaction is not so pronounced as that 
of tuberculin in tuberculous cattle. Our experience has not been 
satisfactory in the cases tested although in a few of them a distinct 
temperature curve was obtained. Meyer states that we are not justi- 
fied in recommending the avian tuberculin as a diagnostic agent for 
paratuberculosis, and that the ophthalmic test, as recommended by 
Howe, is also unreliable. Holth, also Twort and Ingram, have pre- 
pared a tuberculin (paratuberculin) from cultures of the Johne’s 
bacterium, which they report to be successful. They obtained maxi- 
mum temperatures in three cases of 105°, 106.1° and 104.8° F. 
respectively. 
Sera tests. Both the agglutination and complement fixation 
methods have been tried. The results are not satisfactory and the 
experimental work with these methods is too meager to warrant their 
recommendation at present. 
The diagnosis depends upon a combination of the physical condi- 
tions, histological and bacteriological findings together with the 
reactions obtained with the specially prepared tuberculin. There is 
no reaction in animals affected with this disease to tuberculin prepared 
from the human or bovine varieties of tubercle bacteria. 
Johne’s disease is to be differentiated from tuberculosis and para- 
sitic enteritis. Miessner and Trapp have mentioned a case of sar- 
comatosis of the bowel in which the animal gave every symptom of 
Johne’s disease. Twort and Ingram point out coccidioses as a condi- 
tion to be differentiated. It is accomplished by finding the coccidium 
cyst in the feces. The diagnosis is made on the accumulation of evi- 
dence of Johne’s disease and the absence of causes to otherwise 
explain the physical condition. It is presumed that ere long more 
definite methods of diagnosis will be formulated. 
Prevention. M’Fadyean states that in all the cases which have 
come under his observation there was a history of similar cases on the 
farm, in several instances extending back over a period of many 
years. During the advanced stages of the disease large numbers of 
the bacteria are voided with the feces, and under all ordinary circum- 
stances there are ample opportunities for infection from this source. 
In this way both pasture and other materials as well as drinking 
water may become seriously contaminated. At present there is no 
