16
carried on in one in which cases of the disease had occurred, and although
careful disinfection was carried out, in some instances the animals became
infected from others in the same shed, mostly at a date which was beyond the
incubation period of the disease, so that it was certain that the infection was
here a natural one, caught from the infected sheds and not from the skins
which were being tested, and only proved that the animal was susceptible to
the disease and yet had failed to get it from the skin injections within the
extreme known incubation period of the disease. I should also mention
that all of the animals which did not get the disease from the skins were sub-
sequently injected with virulent blood and proved to be susceptible by their
contracting the disease in every case except one, and this solitary exception
was also given at the same time a large dose of protective serum, which was
sufficient to prevent him contracting the disease. In every fatal case the diagnosis
I was confirmed by a post mortem examination. Moreover, all the cases
which natural infection followed the skins injections in the infected shed
were subsequently controlled by a final experiment in a shed in which no
cases of rinderpest had ever occurred. The temperatures, pulse and respira-
tions of all the animals were taken twice a day and recorded on a chart, together
with the symptoms for ten days after the injection, while the extreme incuba-
tion period of the disease mentioned in the reports from South Africa is eight
days, and I have never seen it to be as long as that in any animals tested in
this Laboratory. The animals used were all Hill cattle, which I find are much
susceptible to the disease than Plains animals. The sun temperature at the
place where the skins were being dried was recorded with a solar radiation
thermometer three times a day, and the shade maximum and minimum
temperatures were also recorded together with other meteorological data, and
it will be seen from the records given with the experiments that these tem-
peratures are lower than would be likely to be met with in most Plains stations
at any time of the year, so that the length of time that was found necessary
in the different processes for the destruction of virus in the hides tested at
Muktesar will be at least as long as, if not longer than, would be required in
the Plains, so that the results obtained here may reasonably be held to apply to
all those parts of India in which there is any material trade in hides.
The experiments were carried out in three series, the first of which only
applied to dried skins and were undertaken to get a general idea as to the
probable duration of the infection, while, as the skins had been kept in the
post mortem house until shortly before they were used, which is, perhaps, the
most infected spot in the place, it was recognised that some of them might
have become recently reinfected from the place where they had been kept,
and the test was of more negative than positive value. The second series was
carried out with skins that had been treated by a professional native Chamar
(hide curer) with skins which were kept in an uninfected room and hung up
separately from each other. The third series were carried out in the same way
as the second series, only in an uninfected shed. The results of each experiment
will now be briefly recorded.
FIRST SERIES OF EXPERIMENTS.
31. Experiments No. I.—A small bull, aged 5½, was injected subcutane¬
ously on March 4th, 1899, with 10 c.c. of an extract made with normal saline
solution (0.6%) of small pieces of the hide of a bull that had died of inoculated
rinderpest on February 12th. The skin had been dried in the sun for 18 days,
during which time the maximum temperature in the shade had varied between
51° and 60°F., and the minimum temperature between 34° and 44°F.
Result.—The temperature, pulse and respiratory curves remained normal
for ten days and no symptoms of disease appeared. This animal was subse-
quently used for another experiment and contracted rinderpest and died of
the disease, proving that his failure to become infected by the skin extract
was not due to insusceptibility to the affection.
Experiment No. II.—A small bull, aged 1½, was inoculated subcutaneously
on March 4th with 8 c c. of an extract of the hide of an animal which had died
of inoculated rinderpest on February 5th, and which had been allowed to dry
in the post mortem room with other skins for 26 days, during which the maxi-
mum temperature in the shade had varied between 38° and 60°, and the minimum
between 28° and 44°F.