d comprehensive conclusions followed from a comparatively
few experiments upon animals, and apparently no effort had been made to
learn to what extent human tubercle bacilli may differ in their virulence
for cattle or what grades of virulence there might be among bacilli of
bovine origin. Vagedes had already shown that bacilli were sometimes
present in human lesions which were as virulent as bovine bacilli, but his
work was wholly ignored by Koch.

A considerable number of investigators, including Chauveau, Vagedes,
Ravenel, De Schweinitz, Mohler, De Jong, Delepine, Orth, Stenstroem, Fibiger
and Jensen, Max Wolff, Nocard, Arloing, Behring, Dean and Todd, Hamilton
and Young, the German Tuberculosis Commission, and Theobald Smith, have
found tubercle bacilli in the bodies of human beings who died of
tuberculosis which proved to have about the same virulence for cattle as
had the bacilli from bovine animals affected by the disease.

Kossel, in a preliminary report, stated that the German commission had
tested 7 cultures of tuberculosis from cattle and hogs--4 from cattle and 3
from hogs. Two proved acutely fatal in cattle after eight to nine weeks; 4
likewise produced a generalized tuberculosis, but which certainly had a
more chronic course, while 1 of the cultures caused only an infiltration at
the point of inoculation, with some caseous foci in the adjoining
prescapular gland and in one of the mediastinal glands, and there was
lacking the spreading of the tuberculosis over the entire body which they
were accustomed to see after the injection of cultures of bovine
tuberculosis. "Hence," says Kossel, "among bovine tuberculosis bacilli
there can also occur differences with regard to the virulence."

The German commission also tested 39 different freshly made cultures from
tuberculous disease in man. Nineteen did not produce the slightest symptoms
in cattle; with 9 others the cattle exhibited after four months very minute
foci in the prescapular glands, which were mostly encapsuled and showed no
inclination to progress; with 7 other cases there was somewhat more marked
disease of the prescapular glands, but it did not go so far as a material
spreading of the process to the adjoining glands. There were 4 cultures,
however, which were more virulent and caused generalized tuberculosis in
the cattle inoculated with them.

It would appear, therefore, that hereafter everyone must admit that it is
impossible always to tell the so