INFECTIOUS DISEASES OF CATTLE. 431 



Oil a large fa I'm. on which before the injection tuberculosis had appeared 

 in a vicious form, the owner had the impression that the severe cases had after- 

 wards become more numerous. He had, however, not suffered severe losses, 

 and S months later the large reacting division by no means made a bad 

 impression. Finally, it is to be noticed that tuberculin has been employed on 

 a large scale in Denmark for years, and still the demand from farmers con- 

 stantly increases. This could certainly not be the case if the injections were 

 generally followed by bad results. 



Paige said, after the tests of the herd of the Massachusetts Agri- 

 cultural College, that "its use is not followed by any ill effects of a 

 serious or permanent nature." 



Lamson, of the Xew Hampshire College Agricultural Experiment 

 Station, said : "There is abundant testimony that its use is not in any 

 way injurious to a healthy animal." 



Conn, who made a special study of the present attitude of Euro- 

 pean science toward tuberculosis in cattle, reached the following 

 conclusions : 



It has been, from the first, thought by some that the use of tuberculin produces 

 a direct injury upon the inoculated animals. This, however, is undoubtedly a 

 mistake, and there is no longer any belief anywhere on the part of scientists that 

 the injury thus produced is worthy of note. In the first place, the idea that it 

 may produce the disease in a perfectly healthy animal by the inoculation is abso- 

 lutely fallacious. The tuberculin does not contain the tubercle bacillus, and it 

 is absolutely certain that it is impossible to produce a case of tuberculosis in an 

 animal unless the tubercle bacilli are present. The use of tubei'culin, therefore, 

 certainly can never produce the disease in the inoculated animal. 



It has been more widely believed, however, that the inoculation of an animal 

 with this material has a tendency to stimulate an incipient case of tuberculosis. 

 It has been thought that an animal with a very slight case of the disease may, 

 after inoculation, show a very rapid extension of this disease and be speedily 

 brought to a condition where it is beyond any use. The reasons given for this 

 have been the apparent activity of the tuberculosis infection in animals that 

 have been slaughtered shortly after Inoculation. This has been claimed, not 

 only by agriculturists who have not understood the subject well, but also by 

 veterinarians and bacteriologists. But here, too, we must recognize that the 

 claim has been disproved, and that there is now a practical unanimity of opinion 

 on the part of all who are best calculated to judge, that such an injurious effect 

 does not occur. Even those who have been most pronounced in the claim that 

 there is injury thus resulting from tuberculin have, little by little, modified 

 their claim, until at the present time they say either that the injury which they 

 formerly claimed does not occur, or that the stimulus of the disease is so slight 

 that it should be absolutely neglected, in view of the great value which may 

 arise from the use of tuberculin. Apart from two or three who hold this very 

 moderate opinion, all bacteriologists and veterinarians unite in agreeing that 

 there is no evidence for believing that any injury results. In Denmark, espe- 

 cially, many hundreds of thousands of animals have been inoculated, and the 

 veterinarians say there is absolutely no reason in all their experience for 

 believing that the tuberculin inoculation is followed by any injurious results. 



In 1898 tuberculosis was found in the large Shorthorn herd belong- 

 ing to W. C. Edwards, of Canada, who with commendable prompt- 



