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under very different conditions many months before. If the surra parasite in some
form or other develops in ponds which dry up during the hot season, the germs or ova
would be widely scattered by the wind, which raises the dust of the beds of those
ponds afterwards, the spores or ova would be sown broad-cast, many would rest on
the food, others on the drink of horses, thus being conveyed into the stomach, while
others would be inhaled into the lungs and develop by the moisture and heat there,
then pass into the circulation. Possibly that may in some measure account for the
disease prevailing much more this year and the last, which were very dry and hot,
than the previous year (1878), which I was told was a very wet one in the district of
Dera Ismail Khan. If, again, the horses daily drank water from a source in which
these organisms naturally developed, then that would be the most common way
in which they were conveyed into the system, and that water would be the chief
remote cause of the disease. My opinion is that such is the case in the district of
Dera Ismail Khan. I cannot prove it, for I have not been able to find the parasite
in the water; but I declare that the water which the horses drink is very impure and
obtained from shallow, narrow, winding irrigation channels choked with sedgy
vegetation and slime, most favorable places for the breeding of all kinds of low
organisms. For a further description of them I beg to refer His Honor to appendix
K. That the water is of a marshy character is further shown by the presence of
flukes in the liver of two surra cases I made a post-mortem examination of.
28. With regard to the food being the remote cause, it has been suggested that
the disease is due to the horses eating grass from low inundated land on the banks of the
Indus, &c. Major Money, 4th Punjab Cavalry, informed me that the disease was
common among the horses of the 3rd Punjab Cavalry when they got grass from
inundated ground near the Indus, but it ceased when they got grass from higher
ground. It is not improbable that such grass would convey the ova of the parasite ;
but it is not the common cause at the outposts, for the disease comes on when the horses
feed on chopped straw and drink irrigation water at the base of the hills 40 miles
beyond the reach of the Indus, just as much as when they feed on grass, and the
disease prevails, moreover, at these posts far more than at Dera Ismail Khan, close to
the Indus, where they get better water from wells.
29. I cannot praise the horse standings at all the posts: some of them were very
much soiled, but upon the whole they were not worse than the average of native
cavalry, and I do not think the disease comes from this source. However, I would
strongly recommend that the standings be raised and kept even and the soil renewed
periodically. There was an abundance of clean dry earth and sand near all the posts,
but I saw none used to put on the ground when horses stale, to keep the stalls dry
and clean, as is the practice in all well-regulated stables and horse lines in India.
30. Ultimate causes.—These are still more obscure. They comprise all those
atmospheric and other conditions which favor the development of all low organisms,
—the " blight" upon vegetables, and epidemic disease (cholera, &c. among men. I
have already referred to how germs are scattered more in dry seasons than in wet; the
more dust there is blown about, the more broadcast are the spores and ova of low
organisms sown, but the seeds of disease are not so plentiful to be scattered one dry
season as at another. No doubt electrical conditions play a very important part, and
very probably the conditions of the u spot" upon the sun also, as ultimate factors in
the causation of disease germs. There is no doubt that surra, though enzootic as a
rule in certain districts, does become epizootic in some years, as the tahsildar of Tank
informed me that about twenty years ago his uncle, the late Nawab, lost every one of
his horses from surra, about 300 in number, and that the disease was not very common
since then until last year, though the sanitary conditions of the water, &c., remained
the same. With regard to the influence of the different seasons of the year, I failed
to get accurate statistics, as many horses of the 4th Punjab Cavalry have died with
no record to show when they were first reported sick ; but there is abundant evidence
to show that the outbreak takes place usually in August and more in September,
continues until January, then it suddenly ceases.
31. Prevention.—The important practical question is, if the cause of the disease
does come from the water, can we so alter its quality that the parasite will not breed
in it when the most favorable ultimate or atmospherical causes prevail, as in epizootic