IMMUNITY IN TUBERCULOSIS 243 



even anticipated those of Behring. By using for injection first tubercu- 

 lin and then in succession tuberculin and tuberculous material con- 

 taining bovine and possibly human tubercle bacilli, McFadyean suc- 

 ceeded in increasing the resistance of several cattle to artificial tubercu- 

 lar infection. 



Pearson and Gilliland, 1902, in this country early published ac- 

 counts of some experiments which they carried out upon the immuniza- 

 tion of cattle from tuberculosis. They employed a culture of human 

 tubercle bacilli for producing immunity and found that subsequently 

 the protected animals, as compared with the controls, which all suc- 

 cumbed to the virulent inoculation, either developed no lesions or very 

 inconsiderable ones upon being given large quantities of highly patho- 

 genic bovine cultures. As far as I know these experimenters 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 practise, the facts 

 are of considerable theoretical interest, especially in view of the some- 

 what similar means employed to arrest tuberculosis in man. 



The immense importance to scientific agriculture of the matter of 

 immunization of cattle from tuberculosis and the even greater collateral 

 interest which the subject has for man, as enlarging the possibilities 

 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 ISTeufeld's writings that, while working 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 medi- 

 cine, 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 discovered properties to a 

 practical test of immunity occurred to the several independent workers 

 in bacteriology. There can, I think, be no doubt that Behring deserves 

 the credit of making the protection of cattle from tuberculosis a feas- 

 ible, practical object of study. This alone is a merit of no small order. 



From the mere fact that cattle have been successfully protected 

 from infection by the tubercle bacillus, even under the severest condi- 



