On examining the brain of sheep thus affected, what appears to be a watery bladder, called a hydatid, is found, which may be either small or of the size of a hen’s egg. This hydatid, one of the class of entozoöns, has been termed by naturalists the hydatis polycephalus cerebralis, or many-headed hydatid of the brain; these heads being irregularly distributed on the surface of the bladder, and on the front part of each head there is a mouth surrounded by minute sharp hooks within a ring of sucking disks. These disks serve as the means of attachment, by forming a vacuum, and bring the mouth in contact with the surface, and thus, by the aid of the hooks, the parasite is nourished. The coats of the hydatid are disposed in several layers, one of which appears to possess a muscular power. These facts are developed by the microscope, which also discloses numerous little bodies adhering to the internal membrane. The fluid in the bladder is usually clear but occasionally turbid, and then it has been found to contain a number of minute worms.
Treatment. This is deemed an almost incurable disorder. Where the hydatid is not imbedded in the brain, its constant pressure, singularly enough, causes a portion of the cranium to be absorbed, and finally the part immediately over the hydatid becomes thin and soft enough to yield under the pressure of the finger.
When such a spot is discovered, the English veterinarians usually dissect back the muscular integuments, remove a portion of the bone, carefully divide the investing membranes of the brain, and then, if possible, remove the hydatid whole; or, failing to do this, remove its fluid contents. The membranes and integuments are then restored to their position, and an adhesive plaster placed over the whole. The French veterinarians usually simply puncture the cranium and the cyst with a trochar, and laying the sheep on its back, allow the fluid to run out through the orifice thus made. A common awl would answer every purpose for such a puncture; and the puncture is the preferable method for the unskilled practitioner. An instance is, indeed, recorded of a cure having been effected, where the animal had been given up, by boring with a gimlet into the soft place on the head, when the water rushed out, and the sheep immediately followed the others to the pasture.
When, however, the hazard and cruelty attending the operation, under the most favorable circumstances, are considered, as well as the conceded liability of a return of the malady—the growth of new hydatids—it is evident that in this country, it would not be worth while, except in the case of uncommonly valuable sheep, to adopt any other remedy than depriving the miserable animal of life.
OBSTRUCTION OF THE GULLET.
A BARRACK FOR STORING SHEEP-FODDER.
After pouring a little oil in the throat, the obstructing substance which occasions the “choking,” can frequently be removed up or down by external manipulation. If not, it may usually be forced down with the flexible probang, described in “Cattle and their Diseases,” or a flexible rod, the head of which is guarded by a knot, or a little bag of flax-seed. The latter having been dipped in hot water for a minute or two, is partly converted into mucilage, which constantly exudes through the cloth, and protects the œsophagus, or gullet, from laceration. But little force must be used, and the whole operation conducted with the utmost care and gentleness; or the œsophagus will be so far lacerated as to produce death, although the obstruction is removed.