7
and eighth days of the disease. A local swelling forms at the seat of the
inoculation, which is slowly absorbed, and ten days after the injection the
animal is found to be immune to the disease. The duration of this immunity
is very variable, being occasionally only of some three weeks' duration, and its
average, as a result of many thousand inoculations in South Africa, has been
found to be about four months. As, moreover, it was found impossible after
the bile method to use other methods of producing a permanent immunity in
the same animal, the method has been abandoned in South Africa in favour of
others which produce a much longer or a permanent immunity. The bile was
also found in the experience of most authors to actually originate the disease
in some instances.
14. The Glycerineated bile method of Dr. Edington.—To overcome the
above mentioned objections, Dr. Edington, of the Grahamstown Bacteriological
Institute, introduced a method in which bile from animals which had died of
rinderpest, but which was not putrid or thin and light yellow, was mixed with
half its- bulk of glycerine, and after being kept for eight days was injected
subcutaneously, and followed after ten days with a very small quantity of
virulent blood, by which means a mild attack of the disease was produced
which would ensure a permanent immunity from the disease. Over three
hundred thousand animals have been treated by this method with a loss of only
8 per cent. A slightly larger quantity of bile is required for this method
than in Koch's, but on the other hand there is no necessity to kill the animals
on the sixth to eighth day in order to get the bile, and it is claimed that a
larger proportion of biles are available for use by this method, while it will
not originate the disease in a healthy herd, although it should be mentioned
that the advocates of the Koch's bile method claim that pure biles also never
produce the affection.
15. Defibrinated Blood of salted animals.—This method, which was carried
out on a large scale in the Transvaal by Messrs. Danysz and Bordet, consists in
the inoculation of a large quantity of defibrinated blood obtained from an
animal which had passed through an attack of rinderpest, and into which in
some cases doses of virulent blood had been injected in order to increase the
active immunity of the animals. The inoculated animal was then exposed to
natural infection, by which means, being partially protected by the injection,
they contracted a mild form of the disease, and were rendered permanently
immune to it. This method was a great advance on the previous ones, and
forms the basis of the improved serum method to be mentioned immediately,
but it had the disadvantage of requiring large injections, and of there being a
risk of malarial fever or red-water fever being conveyed to the inoculated
animal, but fortunately the latter objection does not apply to this country, as
far as we know.
16. Simultaneous Serum method of Turner and Kolle.—This method,
which has been very widely adopted in South Africa with most encouraging
success, is an improvement on the last mentioned one. It consists in injecting
a small dose of a powerfully protective serum (obtained by repeated injections
of gradually increased doses of virulent blood into a salted animal, and the
separation of the serum from its blood), and at the same time a small dose of
virulent blood into a different part of the animal's body. A mild form of the
disease is produced in 90 per cent. of the animals, with a loss of only one-
half per cent., and with the production of a permanent immunity, while the
other 10 per cent., are also protected for some months even though they fail to
react. The latest report on this method states that in Rhodesia over 100,000
animals had been inoculated with a loss of less than 1 per cent., and over
90 per cent. of them were permanently protected, with the result that the
disease had been stamped out of this large tract of country.
17. The conditions of rinderpest in India in relation to the question of
protective inoculation.—It might be thought at first sight from the above de-
scription that it only remains to put into practice in India the methods which
have been so successfully used in South Africa, but a moment's consideration
of the great differences between the intensity and distribution of the disease
in the two countries will suffice to show that the problem is not quite so simple.
In the first place, it must be remembered that in South Africa the disease found
itself in a virgin soil, it never having been known there previously, and, like
all epidemic diseases, it consequently spread with frightful rapidity, some
twenty miles a day, and it is estimated by the best authorities that, if no