TUFAIL
AHMED
SIDDIQI
161
As the number of calves inoculated subcutaneously
was less than the number treated by scarification
for comparative purposes data were taken at
random from an old record of subcutaneously—
vaccinated animals* of suitable age and breed,
and reactions consolidated into another composite
chart (Fig. 2). An examination of these two
composite charts will enable a judgement to be
formed of the comparative susceptibility of this
breed to the two forms of inoculation.
FIG. 1. Composite thermel reaction of the 20 calves
immunized by the scarification method under
the experiment.
FIG. 2. Composite thermal reaction of the 20 calves
immunized by the subcutaneous method in 1937
Of the four hill bulls, one reacted and recovered
a second reacted and died, while the remaining two
(Nos. 152 and 416) behaved irregularly, dying
without a characteristic reaction on the 22nd and
23rd day. As no hill bulls were inoculated sub-
cutaneously, it was not possible to make any com-
parison of methods, but in a typical syndrome,
this is not what one would expect to find in this
highly susceptible breed.
It was also observed that the thermal response in
the animals reacting to the scarification route was
delayed, commencing on the fifth or the sixth day
after inoculation.
Immunity tests (Table I). The animals of the
scarification and subcutaneous groups were divided
into four similar lots, for immunity test every three
months. Two healthy hill bulls were also included
to serve as virus controls at each test. All were
injected subcutaneously with 5 c.c. of virulent
hill bull blood, and in addition, the animals under
test were allowed to mix freely with the reacting
controls, so that they were exposed to all possible
outside chances of infection.
Of the scarification group consisting of 19
animals which remained for test there was evidence
of strong immunity in 15 (including the remaining
hill bull), partial immunity in three and in one
(H. C. 79) apparently no protection. Among the
subcutaneous lot of five calves, immunity was
strong in four, and partial in one. One calf
(H. C. 102) of the scarification group and one
(H. C. 104) of the subcutaneous group, though imm-
une to rinderpest, showed resuscitation of blood
protozoa during the test. In no case, however,
was it necessary, either during immunization or
test, to control the reaction by serum. The eight
hill bulls serving as test-virus controls reacted
typically and died.
DISCUSSION
It is evident that in most of the calves there
were no reactions following immunization by scari-
fication. In a few, however, there was a mild
thermal response. It is also evident, that in spite
of the absence or mildness of the reactions, the
immunity conferred by this method could be favou-
rably compared with that obtained by the subcuta-
neous method. Our results in respect of reactions
are apparently in agreement with those of Tuft
[1931] in the case of a potent mixed typhoid
vaccine. This worker immunized over 100 indi-
viduals with small doses of this vaccine intracu-
taneously, obtaining results which were usually
better than those got with larger doses by other
routes and without general reactions. Absence
of reaction or its delayed appearance and mildness
may be attributed to the smallness of the dose of
inoculum absorbed, to its local fixation, or to
slow rate of its absorption. From a practical
*These animals were from amongst a batch of animals
immunized as a routine practice with the goat-spleen-
virus subcutaneously in 1937, with one and the same
brew of vaccine, and in respect of age, breed and immu-
nization history of parents were identical with the animals
treated by scarification in our experiment.