424 DISEASES OF CATTLE. 



and 8 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 New 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 pro- 

 duces a direct injury upon the inoculated animals. This, however, is un- 

 doubtedly 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 perfectl5- healthy animal by the 

 inoculation is absolutely 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 tuberculin, 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 lias 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 in- 

 jurious 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 tlie 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, especially, many hundreds of thousands of animals have been inocu- 

 lated, 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- 

 ness and public spirit had his animals tested, and at once proceeded 

 to separate the diseased from the healthy animals. They were all 

 finely bred animals, and of the very class which we have been told 

 are most susceptible to the injurious effects of tuberculin. After 



