60
walking exercise daily. As it did not thrive on gram, barley (boiled) was given in its place
with the most satisfactory results, the animal rapidly putting on flesh.
An experiment was made with the alkaloid of Adhatoda Vasica (vasicine), which was
observed microscopically to have a certain effect upon the surra hæmatozoon. Twenty-two
grains of the freshly-prepared alkaloid, in distilled water, were injected directly into the
blood-stream of a horse during the presence (numerous) of the hæmatozoon in the circulation.
But although numerous examinations of the blood were made for some hours after the in-
jection, the organism was apparently not affected.
Observations have been made to determine the efficacy of subjecting healthy animals
to drugs sufficient to cause the full physiological effects, previous to submitting them to
experimental inoculation with surra—
(i) By subcutaneous inoculation of soiled blood.
(ii) By communicating the disease in a somewhat similar manner to that in which
it is naturally contracted, viz., by small repeated doses of the hæmatozoon in
water.
The chemicals made use of during these experiments were—
(a) Arsenic.
(b) Tri-iodide of arsenic and bin-iodide of mercury—
(i) In the first instance, although the latent period was not lengthened, the course
of the disease was undoubtedly modified, only a few hæmatozoa being at any
time in the blood; and although the disease has run for some weeks, the
animals still maintain a fair condition.
Owing to the reasons given below the drugs administered were insufficient to
withstand the severe and unnatural test of subcutaneous inoculation.
(ii) As a lengthened period is required to communicate surra by the second method, the
experiments are not yet concluded; but the results as yet obtained warrant one
in believing that they will be successful.
It appears that animals suffering from surra have a greater tolerance of arsenic than
healthy animals when the drug is administered for a lengthened period, as in the above experi-
ments. Difficulty was experienced in getting the horses accustomed to be watered at a river
or tank to take the drug (in water), or even pure water from a bucket. No such difficulty
occurred in treating previously-recorded surra cases received from Bombay, where horses had
always been used to the latter method.
During an acute attack of a disease only lasting a few days it is easy to administer
drugs by drenching; but in the treatment of surra, when it is necessary to administer medi-
cines two or three times daily for a period of some weeks, drenching is out of the question,
as any unnecessary disturbance of the animal, and possible injury to the mouth, is prejudicial
and would certainly retard recovery.
Several interesting physiological problems have been worked out relating to the ingestion
and excretion of nitrogen during health and the course of the disease (surra) under treatment.
The results of these will be published when the cases are completed.
350. Investigations have been conducted in connection with rat surra
with the following results:—
Experiments on animals with the hæmatozoon of the Rat at the Poona Laboratory.
Proof was wanting that this hæmatozoon was capable of producing surra when blood
containing the organism was subcutaneously injected into horses and some other species of
animals. As early as November 1890 I commenced a series of experiments for the purpose
of deciding the above question, and obtained positive results, but found that the periods of
incubation were more prolonged than in horse surra, in one case being as much as 63 days.
Notwithstanding this, the virulence of the disease when once developed was intense, as shown
by the short period during which the animal survived after the appearance of the hæmatozoon
in the blood; this being in three cases only 2 to 5 days.
Inoculation with soiled blood of the rat (mus decumanus).
Of twelve horses inoculated with soiled rat's blood, four animals contracted surra, or
33.3 per cent—
(a)
(b)
(c)
(d)
Period of incubation lasted
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18
29
13
63
days.
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Animal lived
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19
2
2
5
days.
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