21
Result.—The temperature rose on the fifth day and remained high until
the ninth day, when it fell rapidly and the animal died. Buccal vesicles and
ulcers, purulent discharge from the nose, and diarrhœa with the passage of
mucus, were noted during life, and after death a postmortem examination
revealed the usual lesions of rinderpest.
Remarks.—As no case of rinderpest had ever occurred previously in the
shed in which this animal was placed, there can be no doubt that in this case
the disease was produced by the virus which had survived in the marrow
inside the bone for two weeks, in spite of it having been daily exposed to a hot
sun.
Experiment No. XIV.—A portion of the marrow of the same bone which
was used in experiment No. XV recorded above, was smeared on the nostrils of
a bull, aged 1¼ years.
Result.—The temperature, pulse and respiratory curves remained normal;
no symptoms of disease appeared for ten days.
Experiment No. XX.—The femur of an animal which had died of
rinderpest, and which had been placed in the sun daily for nine days, the tem-
perature during which being the same as noted in experiment No. XV, was
placed in the feeding trough of a bull, aged 2½ years, and left there for eight
days.
Result.—The temperature, pulse and respiratory curves remained normal
for ten days, and no symptoms of rinderpest appeared during that period. He
was subsequently inoculated with virulent rinderpest blood and contracted a
typical attack of the disease.
Experiment No. XXI.—Some of the bone marrow from the femur of an
animal which had died of rinderpest, and which had been placed in the sun
daily for ten days, after which the marrow was taken out and placed in the sun
for three days, two of which were cloudy, during which the maximum tem-
perature in the shade was from 70° to 74°, the minimum from 41° to 53°, and
the maximum of the solar radiation thermometer was 150°F., was placed in
the food of a bull and was eaten by him.
Result.—The temperature, pulse and respiratory curves remained normal
for ten days, and no symptoms appeared.
Remarks.—The above experiments are of considerable interest, for they
prove, in the first place, that the virus remains active in the marrow inside the
shaft of a long bone for at least two weeks, even when the bone is exposed to
the sun daily during that time.
Secondly, they prove that the outside of the bone is rendered innocuous in
a few days when placed in the sun, and that the marrow quickly loses its
power of infection when taken out of the bone and exposed to the sun's rays.
The failure of the same bone marrow, which caused infection when injected
under the skin of an animal, to give the disease when it was rubbed on the
nostrils of another animal, may be due to the fatty nature of the material pre-
venting the germs of the disease from coming into sufficiently intimate con-
tact with the mucous membrane to allow of infection to take place. In any
case, as the only way in which the marrow of bones would be likely to come
into contact with a healthy animal would be after they had been ground up
and spread over fields as manure, in which circumstances the infection would
very quickly be destroyed, even if this was done within a month, later than
which the infection even inside the bone is lost, it is evident that there is no
danger of animals becoming infected through the trade in bones.
The preservation of the infection in the marrow has, however, some
practical importance from another point of view. One of the difficulties in
carrying out both experimental work and inoculations in uninfected places
lies in conveying virulent blood to considerable distances without its losing its
power of infecting animals into which it is injected in order to produce the
disease. This difficulty has been found to be a very real one in India owing
to the high temperature through which blood had to be brought up to the
Muktesar Laboratory on several occasions having caused a great loss of virulence.
In South Africa, again, the difficulty has been of some importance, and was
overcome by inoculating a sheep with virulent blood and then sending it
several days' journey to the place where virulent blood was wanted, and then
bleeding it, for it was found that the virus was preserved in the sheep without