IMMUNITY IN TUBERCULOSIS—FLEXNER. 641 
results are not serious: fever lasting several days sets in, the animals 
may cough, and they may eat less and lose somewhat in weight, but 
even they return to what is for them the normal. 
It would appear that McFadyean is entitled to the credit of the 
discovery equally with Behring of the immunization of cattle against 
tuberculosis; and, indeed, there is reason to believe that his results 
even anticipated those of Behring. By using for injection first tuber- 
culin and then in succession tuberculin and tuberculous material con- 
taining bovine and possibly human tubercle bacilli, McFadyean 
succeeded in increasing the resistance of several cattle to artificial 
tubercular infection. 
Pearson and Gilliland, 1902, in this country early published ac- 
counts of some experiments which they carried out upon the immu- 
nization of cattle against tuberculosis. They employed a culture of 
human tubercle bacilli for producing immunity and found that sub- 
sequently the protected animals, as compared with the controls, which 
all succumbed to the virulent inoculation, either developed no lesions 
or very inconsiderable ones upon being given large quantities of 
highly pathogenic bovine cultures. As far as I know these experi- 
menters are the only investigators who have endeavored to carry the 
principles of the method a step farther, so as to bring about arrest 
of the disease in cattle already tuberculous. While it is unlikely 
that such a therapeutic use of “ vaccination ” will ever be made in 
veterinary practice, the facts are of considerable theoretical interest, 
especially in view of the somewhat similar means employed to arrest 
tuberculosis in man. 
The immense importance to scientific agriculture of the matter of 
immunization of cattle against tuberculosis and the even greater col- 
lateral interest which the subject has for man, as enlarging the pos- 
sibilities of immunity even for him, have led to a discussion on the 
priority of the discovery between Neufeld, a pupil of Koch, and 
Behring. It would appear from Neufeld’s writings that, while work- 
ing under Koch’s direction, he ascertained as early as 1900-1901 that 
large animals—donkeys chiefly, but cattle also—could be protected 
from artificial infection with virulent tubercle bacilli, always fatal to 
control animals, by previous treatment with tubercle vaccine, of which 
several different preparations were studied. It is not within the 
scope of this address to apportion the credit of priority; but in any 
case, assuming the facts to be as stated by the contestants, McFadyean 
should receive as great credit as either of the others, if not the chief 
credit. The principle which all the investigators employed is not 
new in experimental medicine, but has come to us from the genius of 
Pasteur. It may, however, be said that our knowledge of the tubercle 
bacillus and its varying activities had by the year 1900 become so 
much enlarged that the possibility of putting the facts of the newly 
