"In all those instances in which I observed them, the green flies were the first to attack, and this is the common opinion among the shepherds. After a time, when the larvæ (maggots) commenced gnawing the flesh, the putrid stench, which was thereby occasioned, attracted numerous other species. The Vomitoria (blue-bottle) was very common, more numerous than both the former species, and perhaps contributed most to accelerate the death of the animal, after the others had commenced. The Carnaria was rare. I observed but few of them, and these seemed not concerned; which is the more remarkable, as in the fenny counties of England it is said to be most troublesome. All the species of this genus resemble one another closely, both in appearance and mode of life. They are exceedingly voracious, feeding upon carcasses and filth of every description. In five days after being hatched they arrive at full growth, provided they have plenty of food; they then cease to eat, and seek to assume the pupa state, crawling under ground two or three inches. Here they remain about fourteen days, when the shell cracks, and the imago, or fly, appears. In this last state, they feed also on putrid juices, sucking them through their probosces."
The correctness of this description of their transformations I can attest, from having watched their habits during my anatomical pursuits in the summer months.
(148.) Treatment of Fly-blown Sheep. When the sheep is fly-blown, dislodge the maggots with a knife, and shake a little powdered white lead into the wound. Do not apply tar to the abraded surface, as, from its cauterizing effects, the wound will be enlarged, and a repetition of the visit speedily ensured. To ward off the onset of the flies, various substances noxious to them are rubbed or poured upon the wool. Tar, in small quantities, and of pungent quality, is by some daubed upon the ears, horns, and tail. Others prefer rubbing a little melted butter, thickened by flour of sulphur, along the sheep's back: this is an effectual preventive. Some, again, prefer dressing the sheep, when in low situations, with the following recipe, which I take the liberty of copying from Mr Mather's paper on the fly, in the Quarterly Journal of Agriculture, No. XXIV.
| "Take of | Arsenic, finely pounded, one pound |
| Potash twelve ounces, | |
| Common yellow soap six ounces, | |
| Rain or river water thirty gallons. |
"Boil the ingredients together for fifteen minutes. * * * * The liquid is in no degree injurious to wool. It cleans and dries the offensive perspiration of the sheep, and destroys the smell caused by the dew in the mornings, or by damp hot weather. In most situations, one dressing in July and another in August will suffice; but as the expense is trifling, and the process simple, it may be better to apply it more frequently, especially in low and damp situations." The liquid is applied only in dry weather. A teapot, or any vessel of a similar form, is filled with it, and one person pours it on the wool, while another rubs the fleece to facilitate the passage of the fluid. At the times of using the solution, all superfluous wool ought to be shorn from the buttocks, but not too closely.
When the insects are very troublesome, drive the sheep if possible to higher ground. Examine carefully all wounds and ulcers, however trifling, and dress them with any simple ointment containing a small proportion of sulphur, mercury, or white-lead. Lastly, bury all useless carcasses as speedily as possible, by which means you will keep down the number of the flies.
(149.) The Sheep-Fag or Ked (Hippobosca ovina) and The Tick (Acarus reduvius), are destroyed or stopped in their attacks by the same remedies and preventives detailed in the preceding paragraphs on the fly.
(150.) Inflammation produced by the Œstrus bovis. This insect infests not only cattle but also sheep and goats, depositing its eggs on the back of the animal, where it forms a small tumour, in which the larvæ remain from autumn till the commencement of the ensuing summer. Only the fattest and most vigorous animals are attacked, and the larvæ are very difficult to destroy. Fischer found, from numerous experiments, that even spirits, and a strong solution of salt, could not affect them. The fumes of burning sulphur alone seemed to annoy them, and to it they speedily fell victims. This, however, is a remedy which cannot be applied to the skin of the sheep, so that our only resource is the repeated application of turpentine to the tumours on the back, taking care to slit them up so as to facilitate its action.
(151.) Sore Teats. When a ewe is observed to hinder the lamb from sucking, its teats should be examined. If much inflamed, a poultice should be applied, and the lamb placed under the charge of another nurse. Suppuration will thus be promoted, and the matter may be allowed to escape by making an opening for it at the place it points. If there is only a little tenderness of the skin, all that is required is the washing it with a solution either of sugar of lead or sulphate of zinc, eight grains to the ounce of water.
(152.) Foot-rot. No disease occasions more acute suffering to the sheep, and annoyance to the farmer, than foot-rot, and no disease has led to longer arguments as to its contagious or non-contagious nature. Thanks, however, to Mr Dick of Edinburgh, these disputes are closed for ever, as any one may be convinced, by perusing his clever and sarcastic paper at page 852, Vol. ii. of the Quarterly Journal of Agriculture. His excellent remarks on the popular ideas of the infectious nature of foot-rot, I have not space to quote, but shall lay before the reader his views as to the situations and circumstances which give origin to the disease.[ [29]