59
point to death from arsenical poisoning, neither in their symptoms nor in their post mortem
lesions.
The decision of this point will best be arrived at by the experimental inoculation of
small animals susceptible to the disease, at different times, during the absence of the infu-
sorian from the blood of the animal under treatment. The effect of doses of arsenic similar
to those used in treatment will be easily determined by experiments on healthy animals.
The number of animals treated with arsenic is at present too few to allow of the question
being properly decided, but there is no doubt that the results achieved in treatment with
the drug are more hopeful than any which have been obtained previously.
The subcutaneous inoculation of blood and its derivatives in its different forms, obtained
from animals suffering from, or which had lately succumbed to, surra, was also tried to
ascertain whether there was any substance capable of conferring immunity against the disease,
but the results were negative.
The efficacy of arsenic as a prophylactic has not yet been demonstrated, and it will
be necessary to do this before its recommendation can be safely made. Probably the best
method would be to subject animals to a course of arsenic, and then to experimental inocula-
tion with small quantities of the infusorian. The other recommendations as to prevention
are in the majority of cases not practicable.
Further experiments in treatment and on the debateable questions are therefore desir-
able, but the facts noted in the report with regard to the nature of the disease are most
valuable.
319. Since that date Dr. Lingard has continued his experiments with
reference to this disease. The following is an extract from a summary of
these further investigations:—
Recent outbreaks of Surra in fresh localities.
Katgodam, North-West Provinces (elevation 1,900 feet).—Before 1890 many tonga
ponies (principally Cabulis) succumbed to surra. Forty also died in 1890 and 15 between
1891 and 1893.
The disease occurs during the rains—first at the Katgodam stables and later at the
stables of the first stage (Bhugia Ghat, elevation 2,500 feet), but never above the latter.
At first the supposed cause was contaminated water; but although pure water has been
supplied since the early part of 1892 the outbreaks continue yearly. Careful observations
in February 1894 revealed the presence of rat excrement in some quantity in the grain stored
for future use.
In 1893 an outbreak occurred in the stables of the dâk ponies running between Saha-
runpore and Mussoorie. (Rayment.)
In the same year a horse arrived in the Port of Bombay from the Persian Gulf suffer-
ing from surra.
(Mills.)
In Burma (1893) the Kachins lost 14 elephants from the disease out of a total of 32
used for timber-drawing. (G. H. Evans.)
Other outbreaks have occurred—one in Sind among the horses of the Preventive
Force (Police Report) and others, details of which have not been received.
Treatment of Horse Surra.
Since the publication of the last report, the experimental treatment has been continued
with success, the hitherto fatal disease having now proved amenable to certain drugs. The
following is the outline of the first case.
The animal contracted surra by gastric ingestion of soiled blood after a latent
period of six days. Treatment was commenced at once, consisting of arsenic as Liquor
arsenicalis, in 4-grain doses bis die, increasing rapidly to 12-grains daily.
After
a paroxysm of five days, during which time the haematozoon was very numerous, it
disappeared from the blood. The arsenical treatment was continued for 65 days, 454
grains of arsenic being administered. At this period the animal showed an aversion to
the arsenic in this form. For this reason, and as previous experience pointed to the
fact that arsenic by itself did not, in some cases, destroy the resting (or immature form
of the) hæmatozoon, the double iodide of arsenic and mercury was substituted, as it
was known that the iodide of mercury does not form an albuminate, and consequently
the whole of the salt would be available. The iodides were continued for a period of 106
days in order to insure the absolute destruction of the immature form. In all 1,822.75 c.c.,
or 288 grains, each of the tri-iodide of arsenic and bin-iodide of mercury were given.
Since the medicine was discontinued about eight weeks have elapsed, and the animal is in good
health and condition; and no hæmatozoon has appeared in the circulation for 224 days, or
over seven months. For 6½ months during this period this animal has averaged 4½ miles