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the dry shore of an ancient sea. From there the land slopes to the Indus, the soil at first
becoming less stony, more gravelly and sandy ; then the gravel disappears, and there is more
and more of alluvial mud mixed with the sand as we approach the Indus, but the sand remains
in a large proportion.
5. The streams and rivers which come within our borders from the Suliman valleys are
not allowed to reach the Indus except by percolation through the soil. My opinion is that,
owing to its being spread over such an extensive area of dry sandy soil, the water is nearly all
evaporated by the heat of the sun before it reaches the Indus.
6. As soon as a river comes well within our boundary, the natives dam it, and make
what they call a "bund." From this dam channels are made to carry the water in different
directions on the plain. As these main channels proceed, they divide and sub-divide into a
perfect net-work of small channels, about a foot wide and a few inches deep, circulating round the
small enclosures and inosculating with each other. From them water is drawn to irrigate the
fields about the villages, and from them men and animals drink, until at last the water becomes
expended, so that the channels cannot be conducted further.
7. There are very few wells in the district outside Dera Ismail Khan. It may be said that
there is no cultivation anywhere except where the land is irrigated, as I have described, from the
rivers coming in from the Suliman hills. Beyond these net-works of irrigation-channels the land
is a barren desert.
8. These shallow courses are made to circulate in a manner to check the too rapid flow of
the water, and this arrest is further encouraged by allowing sedgy vegetation to grow freely in
them. I found the water often stagnant and exposed to a tropical sun for hours when the
channel was dammed at distant points for the purpose of irrigation. Nothing could be contrived
more favorable for the development of the lowest forms of organic life, animal and vegetable,
and these I found swarming and often visible to the naked eye in a clear glass bottle exposed to
the rays of the sun. The farther the channels are from the main arteries the more does the water
approach the condition of marsh water, and we should expect animals which drink such water to
be infested by parasites found in animals pastured on marsh lands. Accordingly, I found flukes
in the livers of two of the horses which suffered from surra. The fluke is an exceedingly rare
parasite in the liver of the horse. I never saw one before, and very few Veterinary Surgeons
ever have found one in that animal, though they are not uncommon in the ass in England,
because he is ill-cared for and pastured on waste places, commons, &c., where the land is more or
less of a marshy character and the water stagnant. The presence of the flukes in the livers of
these horses is alone a proof that the water which they drank was not good. The parasites could
not be traced to any marsh grass, for there are no marshes proper in the district: the soil is too
porous, and the climate too dry. The horses were fed on grass grown on dry sandy soil or else on
chopped straw. The bottom of all the irrigation channels which I saw was slimy.
9. My opinion is that the cause of surra is taken in by the horses with the water which they
drink, that the dirty condition of the wells at Dera Ismail Khan favors the development of that
cause to some extent, but that it is developed mostly in water conveyed by shallow winding,
sedgy, slimy, water-courses such as I have above described exposed to the influence of a scorching
sun and a cloudless sky.
10. There are three ways of avoding it. First, get pure well water. I am told that no good
well water can be got at the outposts by the native mode of digging: the water obtained is far too
salty. Could not an Artesian well be made deep enough at reasonable cost to obtain good water
from a lower stratum ? Secondly, if no good water can be obtained from wells, the water from the
irrigation channels should be boiled every day before the horses drink it. Thirdly, draw water
for the horses direct from the rivers above the irrigation channels by means of pipes.
11. Filtering the water through a bed of clean sand 3 feet deep has been suggested
to me; but I do not think it would be effective, for the filter would require very frequent
renewal, and I do not think the native officers in charge of the outposts could be trusted to do
that properly.
12. I made the following notes at the outposts which I visited.
13. Tank, 11th October 1880 —One hundred sabres, 1st Punjab Cavalry. The stables are
low sheds open both sides, the roof only 6 feet from the floor, the floor lower than the ground
outside and very uneven. In four out of five stalls I examined the soil was impregnated with
urine 5 or 6 inches deep in the centre. The roof should be elevated, and the standings raised
one foot at least above the surrounding ground. The surface drains all about the lines are very
dirty, with grass and slime choking them. Water is made to flow slowly through these drains
every day drawn from irrigation-channels, to promote the growth of young trees in the lines.
There is a small open pond or tank 30 by 37 paces on the east of the bazaar, where all the men
bathe ; the water is stagnant and exceedingly dirty, full of infusoria and frogs, &c., with a slimy
bottom: fresh water is brought in occasionally from a shallow irrigation-channel, about a foot
and-a-half wide, about 4 miles distant from the river Zam; the bottom of the channel is slimy,
and the flow of water is intercepted by sedgy growths as well as by its tortuous course, favor-
ing the development of low organisms, infusoria, &c. The horses are now supplied with water