ade a special study of the present attitude of European 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 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 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, especially, many hundreds of thousands of animals
have been