29
passed through an attack of rinderpest or been subjected to in-
oculation with rinderpest bile or serum.
(ii) Subject the calf of a cow, which has passed through an attack of
rinderpest during the period of pregnancy, to milk supplied by
a foster mother which has not been protected by an attack of
the disease or by artificial means, with a view to determine
whether the immunity is inherited, or the effect of suckling the
milk of a protected mother.
(iii) To test each animal with virulent rinderpest blood, at a later date.
24. Preparation of a highly immunised serum in fourteen days. Rapid
method.—The preparation of a hyper-immunised serum, capable of conferring
protection against rinderpest to the animals subcutaneously injected with small
quantities of (10 to 20 c. c.) it, takes a considerable period to prepare. An
unprotected animal selected for the purpose of serum giving by the method
of Turner and Kolle, cannot be bled the first time for the purpose of
obtaining protective serum until it has passed through a preparatory period
lasting some 50 to 60 days. In case of a severe outbreak of rinderpest, it is
essential that a reliable prophylactic should be forthcoming with the utmost
despatch in order to combat the outbreak. These experiments therefore are
being undertaken with a view to determine whether some modification of the
above method could not be introduced, so as to do away with the delay entailed
by injecting a series of increasing doses of virulent blood, viz., 10 to 3,000 c. c.,
and by substituting a Rapid method, one injection of 3,000 to 6,000 c. c.,
according to body weight of animal being administered and serum prepared
from blood drawn 14 days later. The results of these experiments are not
quite ready for publication, however the conclusions arrived at up to the
present time are noticed in the next paragraph (result 5).
25. Summary of the Results of Experiments. Serum.— (1) Hyper-
immunised serum (10 c. c. per 600 lbs.) prepared by the Clotting method
between February 24th and April 12th, 1899, has been found to retain its
initial strength (power of protecting against rinderpest) twelve months later
when tested upon plains animals.
(2) Serum prepared by the Clotting method, which occupies from 8 to 12
days, is always found by Cultures to contain micro-organisms although 0.5%
carbolic solution is added, whereas serum prepared by centrifugal action is
found free from organisms, several months later.
(3) Animals protected by the Simultaneous method with serum prepared
by the Clotting method, present more local symptoms at the seat of inoculation,
than animals treated with protective serum collected by centrifugal action, due
to presence of putrefactive micro-organisms in the former.
(4) For the injection of serum giving animals, virulent blood should be
drawn from the Control, as soon as possible, after the maximum temperature
has been recorded, 3 to 5 days after the rise in temparature. By this means a
much higher protective power (5 c. c. per 600 lbs.,) will be acquired by the
serum of the animal injected ; whereas if taken when the temparature is falling
and symptoms of the third stage of rinderpest have supervened, much risk is
run of obtaining serum of low protective power (20 c. c. to 30 c. c. per 600 lbs.)
or even of secondary infection.
(5) Serum (i) Animals susceptible to Rinderpest.—A naturally or artifi-
cially protected animal is subjected to a large injection subcutaneously of
virulent rinderpest blood, varying from 3,000 to 6,000 c. c. according to the
body weight of the animal selected. After an interval of 14 days, to allow for
the subsidence of the reaction, the animal is bled and serum utilised at once.
Within a period of 55 days, this animal may be bled ten times and made to
furnish an immunised serum of high standard.
The results of these experiments are not quite ready for publication ;
however, it may be stated that up to the present time, plains animals by the
Rapid method furnish a protective serum of 10 c.c. per 600 lbs. in 14 days:
buffaloes furnish a serum in 17 days, which produces no reaction with 15 c. c.
per 600 lbs. on plains animals, so that it is probably a 10 c.c. serum. The