34
REPORT OF THE IMPERIAL BACTERIOLOGICAL LABORATORY,
In the first experiments the method of attempted cultivation was
to sow the candle fluid into serum obtained with the strictest precautions
to prevent escape of its carbon dioxide into the air and separated as
quickly as possible from the solid blood clot, and then placed under
paraffin in sterile bottles. Subinoculations were made from this genera-
tion into one or two per cent Bacto-peptone in Fleisch's (1922) modifica-
tion of Ringer's solution, with a fragment of fresh sterile potato added to
increase the nutritive qualities. The third subculture in a large flask
of this medium became restored to rinderpest after passage through the
rabbit, but the material had no " vaccinating " effect upon cattle.
In 1923, work was carried out again to repeat the above results,
but confirmation was not obtainable of the cultural part of the work,
and again in 1924, although the candle fluid could be restored to virulent
rinderpest by three rabbit passages, it could not be maintained in the
rabbits. In 1923, some candle fluid eventually produced a febrile
reaction in the rabbits, quite similar to that of rinderpest, but the rabbit
blood failed to set up rinderpest in the ox. The difficulty in regard to
obtaining a good initial tractability on the part of the virus in this sort
of work seems to be very great, but it is known that analogous diffi-
culties were encountered with other viruses before all the factors neces-
sary for saprophytic growth were understood. In 1923, a strain of
the bovine pleuro-pneumonia virus was kindly sent to us by Dr. Heslop
of the Melbourne University, and after much difficulty we succeeded
in obtaining very good growth, as measured by the production of opale-
scene in culture fluid (peptone as prepared by Meyer and Stickel from
liver and pigs' stomachs for the growth of Bacillus botulinus, added to
one half of its volume of meat extract, prepared by heating at 80°C,
with 0.2 per cent. phosphate buffer, passed through bacterial filter ;
it is important to use this medium fresh, for it has a tendency to in-
crease in alkalinity on storage). However, the growth obtained was
found to be quite incapable of causing even a local swelling in injected
cattle. The microscopic appearances were identical to those of the
rinderpest candle fluid, and as has been inferred recently by Dahmen
a large part of the opalescence is due to a protein precipitate and not
the virus, for the stainable bodies are relatively few in both cases to the
forms seen under dark-ground illumination, and the coarse morphology
of which led the early French investigators to call the organism an " as-
terococcus."
These cursory notes on the work done intensively here during the
period under report are written merely to justify the expenditure entailed
in prosecuting the studies. Whether any considerable economic benefit
will accrue from the investigations is very problematical, for if the pre-
liminary indications of the work are substantiated it may transpire that
the cultivation of the rinderpest virus, and of the contagious bovine
pleuro-pneumonia virus, has little more interest than that of the spiro-
chaetes of human yaws and syphilis, for with both these organisms
we know that no vaccinal effect can be set up by the inoculation of cultures
Record must be made of the sterling services rendered by Mr. M. B.