"There is another method by which I have seen some men attempt to judge of the soundness of sheep. It is a well known fact, that when sheep are rotten the lungs swell to a greater size; they therefore lay the sheep down upon its broad side, and pressing the skin in at the flank, up below the ribs, pretend to feel the lungs. But if there is anything to be learned by this I could never perceive it, and have seen some men, who pretended to know most by it, very often mistaken.
"These are the principal rules by which the Highland farmers draw their stocks; and they relate all to ewe stocks; for as to wedders, they are generally all sold off when they are three years old, and those that buy them for feeding mostly buy them by the condition they appear outwardly to be in at the time, and the character of the ground upon which they were bred."
(167.) Jaundice. I have never seen this disease in the sheep, and have heard almost nothing of it; indeed it is very rare, few having ever witnessed cases of it. It is consequently very imperfectly understood, every one who has written about it assigning for its occurrence a different cause. The principal symptoms to be depended on, according to those who have treated it, are a yellowness of the eyes, and an obstinate sluggishness of the animal, almost amounting to sleep. Copious bleeding and two ounce doses of Glauber salts have been recommended for the treatment, which must be gone about promptly, as the disease is said to be quickly fatal. Reasoning from what is known about jaundice in man, I would, were a case to occur to me in the sheep, give a good dose of calomel, say 15 grains, in conjunction with the salts, unless the disease had supervened on rot, when I would substitute ten grains of ipecacuanha for the mercury.
(168.) Dropsy. When it is the concluding symptom of a disease, it may be reckoned part of the complaint itself, and treated accordingly. Often, however, it is the first thing which attracts the attention of the shepherd, and when such is the case it will usually be traced to long exposure to cold and wet. In this event the best plan is to bleed largely, and give two or three smart doses of Epsom salts. When it occurs in young lambs, sweet spirit of nitre, given in the quantity of a tea-spoonful twice a-day, is found to be attended with the happiest effects. Tapping, or, as it is popularly termed, stabbing, or sticking, to permit the escape of the water, is the cure resorted to in South Africa, when it appears in old sheep, after exposure to rain; but this ought never to be resorted to unless under the guidance of a medical person. It would be much better at once to kill the sheep.
(169.) Sturdy. As shown in the tabular view of the diseases, in foot-note to paragraph (121), this affection may be the result either of pressure on the brain from an animal growth, or from the accumulation of a fluid. Serum is in both cases the mechanical cause of the symptoms, but in the former it is eliminated from neighbouring parts by a hydatid, while in the latter it is merely deposited in some of the natural cavities (the ventricles) of the brain, owing to a congested state of the spinal marrow, the result of continued cold upon the back.
Figure 2, Plate VII., taken from Rudolphi, exhibits a view of the animal which gives rise to the first variety of sturdy. It is the many-headed hydatid of the brain, Cœnurus Cerebralis of naturalists. Like the Cysticercus tenuicollis, already described under the head of Rot, it consists of a thin membranous cyst, full or otherwise of serous fluid; but, unlike the aforementioned animal is studded over with groups of little velvety appendages or heads, each of which has a series of barbs projecting round the mouth. Figure 2, a, Plate VII., is a highly magnified representation of two of these heads.
A good idea of the hydatid, as it exists in the sheep, may be derived from an inspection of Fig 1. Pl. VIII., which has been engraved from a sketch kindly furnished to me by my friend Dr Kirk of Deal. Fig. 1 represents the brain of a sheep two years old, which has been affected with sturdy. The right lobe, a, of the cerebellum or lesser brain, is much distended with fluid, which is enclosed in a membraneous bag, as shown at b, where an incision has been made to expose it, and at c, where it is shining through one of the coverings of the brain, the pia mater.
The hydatid is found of all sizes, from that of a pea to that of Fig. 2, Plate VII. Large ones are far from rare, and the ventricle is frequently enormously distended. The hydatid in the brain from which Fig. 2, Plate VIII. was taken, though not filled to repletion, contained ten drachms of serum. The ventricle was consequently much dilated, as shown at a in that figure, and the usual course and size of the convolutions completely altered. Instead of being folded, like the intestines, upon themselves, they proceeded, as seen at b b, from back to front of the brain; while the furrows between them, which are, in the healthy animal, usually too shallow to be measured, were in several places as deep as the length of the lines at c d.
This excessive accumulation of fluid within the brain leads, as might be expected, to the dilatation of the skull, and to the absorption of its walls, when the bones, young though the animal be when affected with sturdy, can no longer be made to yield. For this reason the skull, towards the termination of the disease, generally becomes thin and soft in front of the root of the horn, and in this way offers a spot which, from its being easily pierced, is frequently made the seat of surgical operations. Other parts of the skull also undergo considerable thinning, more so indeed than in front of the horn. The attention of the farmer has hardly, if ever, been called to this fact, though I believe that, for one instance in which perforation occurs in the frontal bone, it will be noticed a score of times on the sides of the head. In a head with which I was favoured by Mr Grieve, Branxholm braes, each temple, exactly beneath the superior extremity of the upright branch of the lower jaw, displayed a circular opening entirely through the bone, wide enough to permit the passage of an ounce bullet.
Whatever may produce pressure on the brain, the symptoms which indicate it are nearly always the same. The sheep has a dull, stupid look, turns very often round and round, and will, when water is in its way, stand staring at it till at last, giddy and confused, it plumps fairly in. If, when the symptoms are very unpromising, convulsive movements should occur, they may be taken as a favourable sign, as they indicate a diminution of the pressure on the brain. A minute description of the morbid appearances in hydrocephalus could serve no good purpose, I therefore pass on to the prevention of sturdy.