MARCH 1948.]
M. K.
SREENIVASAN
25
Experiments on prevention of shock
Three methods have been proposed : (1) The use of immune serum prepared from the same
species of animal, (2 Dividing the amount of antigen into fractions, and giving one or more small
doses and following up with the remainder of the amount after an hour or so. What may be called
a modification of this method and (3) is to give the desensitizing dose of serum in diluted form,
i.e. injection of reagents having an anti-histamine effect.
As to (1), the chief reason why buffalo serum is used in the immunization of cattle is apparently
because, with the defibrinated or exalated blood of buffaloes, the red cells quickly sediment rendering
the use of a centrifuge unnecessary. This is a very important consideration in serum institutes where
large quantities of product have to be manufactured. The use of Bos indicus instead of Bos bubalis
for serum production would introduce great difficulties in practice. As to (2), the method has been
favourably reported upon and if found to be efficacious, should solve the problem. Thus Jacob [ 1940 ]
has obtained useful results in this way. As to (3), a number of products have been tried and research
in this field is continuing more particularly as regards prevention of atopic disorders such as asthma
and hay fever. Thus, Dragstedt, Mills and Meed [1937] found that acute shock in sensitise
dogs could be prevented by extract of adrenal cortex. Holmes [ 1913 ] and Reichel [1939] state
that the simultaneous injection of a small dose of adrenalin, say 1.0 c.c. 1 : 1,000, will reduce the
shock and the reagent may be mixed with the serum. Wolfram and Zwemer [ 1935 ] found cortin
to be successful in sensitized guinea pigs.
In course of this work chief attention was paid to the second method, the principle of which is to
desensitize the animal. Thus in December 1944, 124 hill-bulls were given 25 c.c. blackquarter serum
followed 40 days later by a second similar dose. As expected, there were no reactions. Forty days
later, the animals were divided into three groups : group I of 42 animals was given 25 c.c. blackquarter
serum as a single dose and 10 reacted ; group II of 41 animals was given 25 c.c. healthy buffalo serum
as a single dose an even reacted ; in group III of 41 animals the dose of 25 c.c. blackquarter serum
was divided: 14 animals were given 1.0 c.c. serum, 14 animals were given 2.0 c.c. serum and the
remainder were given 5.0 c.c. serum, one hour later the remainder of the serum dose was injected.
In this third group, nine animals reacted viz., two which had been started with the 1.0 c.c. dose, six
which had been started with the 2.0 c.c. dose and one which had first been given the 5.0 c.c. dose.
These 26 reactors and four non-reacting hill-bulls were then used for further experiments of the same
kind. These animals were divided into two groups of 13 reactor and two non-reactors. After about
40 days, rest, group I was given 25 c.c. blackquarter serum in one dose and nine reacted (including
one of the ' non-reacting ' hill-bulls); in group II the dose of 25 c.c. blackquarter serum was divided
into two parts, the first portion of 5.0 c.c. being followed an hour later by 20 c.c. In group II, eight
animals reacted, viz., one severely after the 5 c.c. fraction and the rest after the remaining 20 c.c.
fraction.
The experiment was continued with the 17 hill-bulls now left as reactors. These animals were
divided into three groups of five, 6 and six bulls and tested 45 days later with blackquarter serum.
The five animals in group I were given 25 c.c. serum as a single dose and all reacted. The animals of
group 2 were given 5 c.c. serum followed two hours later by 20 c.c.; of these six animals, three reacted
severely after the 5 c.c. fraction and one died, one reacted slightly after the 20 c.c. fraction, and two
did not react. The animals of group III were given 1.0 c.c., 1.5 c.c. and 2.5 c.c. serum at two hourly
intervals, followed two hours later by the 20 c.c. fraction; of these six animals, one reacted after the
1.5 c.c. fraction, one after the 2.5 c.c. fraction, two reacted after the final 20 c.c. fraction, and two did
not react.
DISCUSSION
This work has again demonstrated that injections of a foreign antigen set up in cattle a state of
hypersensitiveness, revealed by a definite train of symptoms of varying severity on reapplication of
the antigen. Cattle vary considerably in their powers of response to the shocking agent, differing
in this respect from guinea pigs and rabbits, on which most of the experimental work has hitherto
been done. It has been shown that in the small hill cattle the sensitive state is not readily induced
E