26 ADAPTATION AND DISEASE 



me through the German Consul in Montreal, had forwarded 

 copies of my address to Berlin. Listening to Koch's speech, I 

 could not but feel that he had utilized and perverted the data 

 I had brought together. Basing myself upon those data, and 

 upon experiments which showed that inoculations of the human 

 bacillus would not set up tuberculosis in cattle, I had urged the 

 Canadian Government not, as Koch suggested, to cease the 

 endeavour to eradicate tuberculosis among cattle, but on the 

 contrary to set aside a restricted area, such as Prince Edward's 

 Island, kill or remove all cattle affording the tuberculin reaction, 

 and then to proceed to raise pedigree and other herds in these 

 protected areas, guaranteed free from Tuberculosis, wherewith 

 to supply the rest of Canada, and if need be the world, with 

 sound stock, the danger of these cattle becoming infected from 

 tuberculous human attendants being, as I pointed out, practic- 

 ally nil. And as the Canadian authorities, pending the findings 

 of the British Royal' Commission, took no action, I venture to 

 repeat the recommendation in England as regards the Channel 

 Islands and the Isle of Man. As it is, I believe that the former 

 are already relatively free from bovine tuberculosis. It would 

 not be a difficult matter, therefore, to ensure that the whole 

 original stock of Jersey and Guernsey cattle become absolutely 

 free from this devastating disease, and that the value of the 

 herds become markedly augmented. 



Saying this it would seem that I myself support the doctrine 

 of the fixity of bacterial species, and even of bacterial strains, 

 that I believe not in the adaptive qualities of the bacteria, but 

 in their conservatism. The truth is that I believe in both. 

 As regards these two strains, there are some very interesting 

 data the relationship of which has still to be worked out. Thus, 

 as regards other animals such as the rabbit, the typus bovinus 

 is the more virulent, and while the typus humanus cannot be 

 conveyed to cattle save by the exhibition of unduly massive 

 doses in young and little resistant animals, the typus bovinus 

 can be conveyed to human beings in a more natural course. 

 But here again it is the young and less resistant individuals 

 that are susceptible. Nevertheless if, as Krumweide of New 

 York and others have shown, some 25 per cent of tuberculous 

 children under five years afford the bovine type, how is it that 

 this type is almost unknown in adults ? The evidence at our 



