9
a very slight attack of the disease with a sufficiently long consequent immunity,
will be best suited to the conditions met with in this country; especially as the
protection will be obtained in a very few days. Moreover, the serum in larger
doses can be used as a curative measure in early cases of the disease, if a suffi-
cient quantity is available,—a matter of the greatest practical importance. All
these methods are, therefore, being tested in this Laboratory and the results as far
as they have yet been obtained will be now given, although it should be said
that the experiments are not yet far enough advanced to allow of any definite
conclusions being arrived at on any of the methods enumerated above, and a
special report on the subject will be submitted when they are completed.
Summary of Experiments on Rinderpest as yet carried out.
18. Pure unfiltered bile.—An animal was inoculated with 10 c.c. of good
green bile, and on the tenth day was tested with an injection of 10 c c. of
virulent blood. No disease followed. This animal died of colic on the twenty-
fifth day, and on making a postmortem well-marked lesions of rinderpest were
found in the fourth stomach, and less marked ones in the cæcum. This is very
interesting as showing that the animal had actually suffered from a mild attack
of the disease, although he had never presented any definite rise of temperature or
symptoms of the disease throughout the time he was under observation, the
temperature having been taken twice daily. Whether the disease occurred after
the injection of bile or after the virulent blood it is impossible to say, but such a
case may explain the occasional unusually long duration of the immunity after
the bile inoculations.
A series of animals have been inoculated with bile, and will be tested at
intervals in order to determine the duration of the immunity which may be
expected to result in Indian cattle from the use of this method.
19. Filtered bile.—As so many observers in South Africa have found
that virulent rinderpest sometimes follows injections of bile, it was decided to
test the immunising properties of bile that had been passed through a Pasteur
filter and so deprived of all chance of the danger of conveying the infection to
the inoculated animals. Several animals were inoculated with different doses
of filtered bile, and subsequently either inoculated with virulent blood or
exposed to natural infection in a shed containing animals in an active stage of
the disease. All the animals contracted the disease in various degrees of
severity, some dying of it, although in a smaller proportion than control
animals which were inoculated with virulent blood only. It appears, then,
that only a very slight degree of protection is afforded by this method, and
that it is of too uncertain a degree to allow of cattle, any rate of the Hill breeds,
being safely passed through a mild attack of the disease by first inoculating
them with filtered bile and subsequently with a small dose of virulent blood.
Since these experiments were carried out a paper has been received in which
similar experiments in South Africa were reported to have yielded identical
results, so that it appears to be useless to pursue this question further, unless
better results are obtained in Plains cattle which have not yet been treated in
this way.
20. Glycerinated bile.—This method has also been tested, but so far
without success. Five animals were inoculated with the same dose as is recom-
mended by Dr. Edington for the large South African cattle, which is more than
three times that which would be required in these small Hill animals if their
weight is taken into account. Two of these animals unfortunately developed a
naturally acquired disease in less than ten days, and another on the tenth day,
and all died. Two others were inocculated with 1 c.c. of virulent blood on the 14th
day, and both developed severe attacks of the disease, one dying and the other
very nearly so, showing that no protection had been afforded. As it was after-
wards found that Dr. Edington advises that only 0.2 c.c. of blood should be
used for the second inoculation, six other animals were inoculated with the
dose of glycerinated bile recommended by him, taking into account the weight
of the animals, and on the tenth day they were reinoculated with 0.2 c.c. in
accordance with his directions; but five of them died of rinderpest and the
other was very ill. This method, then, does not appear to be successful in