84                                                 ABSTRACTS

received a second dose of the vole strain. One calf died of allergic reaction following
the inoculation of the second dose. Another calf died from non-specific causes. All
the rest remained apparently healthy. Two of these were killed 44 and 89 days respective-
ly after the injection to follow the reaction due to the inoculation of the vole strain of
acid-fast bacilli. From careful post mortem, histological and cultural examinations, it
was concluded that the vole strain was able to excite in calf a tuberculous reaction,
chronic in nature, which tended to disappear without leaving many traces. It was also
ascertained that sensitiveness to tuberculin following injection of the vole strain deve-
loped very early.

(2) Immunity resulting from vaccination with the vole strain.—The remaining nine
calves (four once-vaccinated and five twice-vaccinated) were tested for their resistance
to tuberculosis along with two controls by the oral administration of 7.5 mg. of viru-
lent bovine tubercle bacilli. The interval between vaccination and resistance tests rang-
ed from 65 to 175 days. The calves were killed at periods ranging from 208 to 223 days
after the resistance tests. Careful post mortem examinations were made and selected
glands were tested for infectivity by guinea-pig inoculation.

Both controls became infected, the glands of the alimentary tract showing wide
spread lesions and some dissemination, slight in one, a little more extensive in the other.

Of the nine vaccinated calves, five were found to have trivial tuberculous lesions in
the glands adjoining the alimentary tract and four showed no macroscopic lesions. Select-
ed glands from the five calves with trivial lesions were tested for evidence of viable orga-
nisms, two guinea-pigs being used for inoculation with material from each calf. In most
instances only one of the two inoculated guinea-pigs developed the disease, showing that
living tubercle bacilli were very scanty in the glands. Of the four no-lesion cases, guinea-
pig inoculation revealed the presence of living bovine bacilli in the mesenteric glands of
two ; the other two harboured no living bovine bacilli.

Of the four no lesion calves, three had received a single dose of the vaccine, (2 intra-
venous and one subcutaneous) and one two doses of the vaccine. It therefore appears
that there was no advantage in giving more than one immunizing dose. As regards
route of administration, the intravenous route is preferred to the subcutaneous, as in
the former no unsightly local reaction was obtained.

As the authors conclude, the results obtained in calves by vaccination with the
vole strain of acid-fast bacilli were good and the method is worth further trials. [V. R. R.]