No. 6. DEPARTMENT OF AGRICULTURE. 469 



I may be thouj?bt audacious to discuss the work of a master who 

 is authority in all inaUcrs which concern baclcriology, and above 

 all in regard to tuberculosis. I know that my intervention is some- 

 what dangerous; however, the interests at stake are so important 

 and the conclusions from Koch's work so frought with grave con- 

 sequences, that 1 cannot hesitate to resjDond to the iovitation of our 

 illustrious president, Lord Lister, to speak my sentiments on the 

 subject. 



That which pleases me in the communication of Koch is that he 

 justifies in a clear manner the efforts of those who protest againsi: 

 extreme methods in the prophylactic measures designed to protect 

 the human race against the dangers of bovine tuberculosis. For 

 some years a salutary reaction has taken place against the extreme 

 measures at first adopted. The communication of Koch will ac- 

 complish this end; perhaps it goes to extremes in the inverse sense, 

 and I fear greatly that after having advised excessive and absurd 

 measures against imaginary dangers, people may now neglect to 

 take precautions against the real dangers which exist for the public 

 health in bovine tuberculosis. 



I have always held, and recently again at the Berlin Congress on 

 Tuberculosis, that bovine tuberculosis plays but a small part in the 

 spread of human tuberculosis; but no matter how small this part 

 may be, it is undeniable, and it would be a great mistake to leave it 

 out of consideration. 



Koch has not succeeded in producing tuberculosis in cattle inocu- 

 lated by various methods with cultures or material from human 

 source. He concludes from this that cattle are refractory to human 

 tuberculosis; that man has nothing to fear from tuberculosis of cat- 

 tle, and that it is useless to take precautions against it. 



With all the respect due to the illustrious savant, but with all the 

 strength of profound conviction, I wish to say that his experiments 

 do not justify such conclusions. 



It is a principle of the experimental method that negative results, 

 however great their number, cannot outweigh positive facts. There 

 exist positive facts proving that it is possible to infect cattle with 

 tuberculous matter from man. The first of these are the experi- 

 ments of my eminent master, Trofessor Chauveau. I regret ex- 

 tremely that his duties prevented him from taking part in this Con- 

 gress; he could have presented them with the authority which be- 

 longs to a master of experimental medicine. I will endeavor to 

 take his place, and to show the value of these facts from the point 

 of view which now engages us. 



Among his numerous experiments on this subject there are four 

 which are particularly strong, in which calves aged from five to ten 

 months were infected by the digestive tract, or by intravenous in- 



