42
Scientific Memoirs by
expansa in some, and another smaller tape worm, which I have not yet been able to
identify, in nearly every case ; and these too no doubt help to swell the mischief.
At the same time, making all allowances for the influence of these parasites, it is, I
am convinced, to the ravages of Œsophagostoma columbianum that the poorness
of our supply of mutton is mainly due.
It is remarkable that, out of over a hundred animals examined, I have never
in the Punjab met with either of the, two lung strongyles which are so destruc-
tive to sheep in some parts of the world.
Diagnosis. —For the stock-keeper the only symptom will be wasting, follow-
ed perhaps by diarrhœa, often of a dysenteric character. The existence of such
symptoms in animals inhabiting any region known to be infected by this para-
site should at once arouse suspicion, and the diagnosis can easily be confirmed
by slaughtering one of the suspected animals and examining the intestines for
nodules. The veterinary expert may make an equally sure diagnosis by merely
examining the dung under the microscope. Owing to their large size the ova
can be seen with a low power in dung mixed with water in a shallow glass tray.
In order to make sure, the ova must be measured, and the best plan will be to
arrange the camera lucida so that it gives 440 diameters, and to compare the
outline with the drawing given in the plate.
Treatment is, from the nature of the case, almost hopeless. No vermifuge
can be expected to exercise any effect on the encysted worms, and it is by
these that the main part of the mischief is effected.
The adult worms could probably be expelled by means of thymol ; but
it may be doubted if they do sufficient harm to make it worth while to attempt
their expulsion. Apart from which, the value of a sheep in bad condition
would, in India, be but little in excess of the cost of the dose.
Prevention. —In this direction too the outlook is not hopeful. It would not
pay to cut grass for sheep, and, as it is impossible to prevent their depositing their
droppings on their grazing ground, the only possible method of prevention lies in
the detection and prompt slaughtering of all infected animals ; but, owing to the
ability of the species to exist continuously as a free nematode, this would have
to be supplemented with periodical burning of grass on pastures, and would have
to be persisted in for a long time before any great results could be expected.
The meat, such as it is, is in no way rendered unsuitable for food, and, as
the sheep cannot be expected to improve while harbouring this parasite, the
sooner they are slaughtered the better for the pocket of the sheep-owner.
As anything like systematic inspection of flocks, however, would be difficult,
even in the most highly civilized of countries, and is entirely out of the question
under the conditions of Indian agriculture, I think the most that can be done is
to encourage grass-burning before the rains. Such a procedure would inflict a
severe check on the mutiplication of the free stage of the species, and would at
least give the lambs a fair start on uninfected pasture.
Curtice suggests stall-feeding, and this would, no doubt, be useful, provided