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580. In addition to the above described series of experiments, Veterinary-
Major Raymond has conducted some tests with what is known as the "serum
treatment." But as this is fully explained in his report it is thought advisable
to produce this interesting note in extenso:—
"The principle involved in serum treatment is this: that an animal which has recovered from an infectious
disease develops in his system a substance which will prevent him from again catching the disease for a very long
time, at any rate. Moreover, the blood of this recovered animal, if taken at the right time and injected into a
healthy one in sufficient quantity, will preserve that healthy animal from an attack for a short time; and as
the effects of the blood injection wear off, the animal may contract the disease in a modified (milder) form and
recover. The blood of a recovered animal may also be used as a curative.
"Leaving general principles, I come to the serotherapeutics of Rinderpest. In 1895, Veterinary-Surgeon
Semmer working in Russia ascertained that the blood of an animal that had recovered from Rinderpest
exercised for a short time an immunising influence, if injected into a healthy animal. In 1896, Veterinary-
Surgeons Pitchford and Theiler, experimenting upon the same lines, confirmed Sommer's discovery, and their ex-
periments were subsequently confirmed by Professor Koch and others. Pitchford and Theiler's experiments had
for their object to confer a passive immunity on cattle by injecting serum obtained from an animal that had
recovered from Rinderpest, and then by means of an injection of virulent blood set up a modified (milder)
a tack which would make these cattle actively immune. Their experiments were stopped to enable Veterinary-
Surgeon Theiler to collaborate with Messrs. Dampz and Bordet, who had been sent out to the Free State from
the Pasteur Institute in Paris.
"These gentlemen have shown that the blood of oxen immunised by an attack of Rinderpest acquires
strength for curative purposes shortly after recovery has been effected, but that the maximum strength is reached
about two months after recovery. The most advantageous time to take blood is said to be from two to six
months after an attack of Rinderpest.
" They ascertained also that the active immunity of a recovered animal can be greatly increased by applying
subsequent injections of virulent blood into the same animal; and when this treatment was adopted, the dose
of immunising serum manufactured from his blood could be reduced. It was known that the amount of serum
from an ordinary recovered case of Rinderpest necessary to give a curative or temporary preventive result was
from 100 to 200 c.c., but by treating a recovered animal with gradually increasing doses of virulent blood, it
was said to be possible to obtain a serum of such strength that 20 c.c. of it was effective.
"But they confirmed the experience of previous observers that serum only confers immunity for a short
time, and that to render the animal immune for a very long period it was necessary he should have an attack of
rinderpest. This attack was rendered milder by serum treatment.
"The treatment of healthy herds, recommended by the Cape Town conference held on the 14th and 15th
October 1897, was to inject virulent Rinderpest blood into one side of the animal and a dose of immune serum
on the other. This process was said to give the disease a modified form, and although some required a second
dose of serum, most of them would recover. The conference, however, recommended that herds should not be
inoculated with serum until the disease had actually appeared in them or in their immediate neighbourhood.
When herds became infected, they were to be injected with serum immediately and those animals which
showed a normal temperature should be injected with virulent blood or kept in close continuous association
with the infected animals. I shall refer to this subject later.
"In case the owner could not procure the serum that was sent out by the Agricultural Department, he
was recommended to use defebrinated blood from animals that had recovered, but they should be healthy and
a period of at least six weeks should intervene between complete recovery and withdrawal of blood. I do not
think it is necessary to go deeper into this method, as it is not suited to Bengal.
"It will bo seen from this short review that the serum treatment is not useful as a preventive, but as a
modifier or curative of the disease, whereas the bile treatment is essentially preventive.
"I may here remark that there is a difference between the Rinderpest of the cattle of South Africa and that
of those in Bengal. In South Africa nearly every animal could be infected, hence an element of certainty was
infused into the experiments, whereas here a fair number of cattle become naturally immune; in South Africa
the mortality is very great, 80-90 per cent. Here (Belgatchia Hospital) with careful nursing, one can save
30 per cent., and one year we saved 50 per cent. Therefore, I started with the idea that, unless the results
obtained after a careful consideration of all circumstances did not amount to 50 per cent., I would entertain
some doubts as to the treatment being worth the cost.
"The experiments which I have concluded at Belgitchia have had for their object to gain some idea of the
probable results of serum treatment in Bengal (a) when used in combination with virulent blood and (b) as a
curative.
"I have done my best to get uniform data by procuring ordinary Dehati animals of equal size, condition
(very poor) and age (18 months to 2 years). Unfortunately, foot and mouth disease broke out amongst some of
them and complicated matters a little, but as the same thing constantly happens in ordinary practice, the evil
had its advantages for the test.
"For some time I had been preparing some super-immunised animals by injecting virulent blood, but the
cost of keep and the difficulty in procuring regular and sufficient supplies of virulent Rinderpest caused me to
part with most of them in exchange for other animals for experimental purposes.
"The serum I used came chiefly from a young buffalo which had received up to 3,200 c.c.m. of virulent
blood, and the material was taken about 3 months after the last injection of virulent blood.
"Except to expedite evident convalescence, no medicine was given and the nursing was confined to what
every ryot would afford.
"The cattle were divided into two groups. One (S) was injected with a dose of Rinderpest blood on one
side and a dose of serum on the other, as follows:—
"First group.—S. A. series comprised 10 bullocks, of which each received 5 c.c. of serum and 0.5 c.c. of
virulent blood. S. B. series comprised 7 bullocks of which each received 10 c.c. of serum and 0.5 c.c. of
blood.
"S. C. series comprised 7 bullocks and each received 10 c.c. of serum and 1.00 c.c. of blood. S. D. series
comprised 7 bullocks and each received 20 c.c. of serum and 1.00 c.c. of blood.
"Under S. A. series I treated some sheep with 5 c.c. of serum and 0.5 c.c. of blood.
"I have kept careful records on charts, but they are bulky and are not attached for that reason, but I
append the results in tabulated form for easy reference.
"The best results were given in S. D. series, by an injection of 20 c.c. of serum and 1 c.c. of virulent
blood, inasmuch as none of the animals died, and 4 out of 7 had a distinct reaction and will be immune, while
in the case of 2, the reaction was doubtful.