Fig. 1.
Condition of the horse in lying posture. Steps to bring one of the hind legs upon the corresponding front one.
By veterinarians who employ the old method of casting with four hobbles, the animal, being properly prepared, is thrown upon whichever side corresponds with the operator’s habit of manipulation, whether with the right hand or the left, and the leg opposite to that on which he is lying being released from the hobble, is carried forward upon the corresponding shoulder, as far as it can be safely done. To effect this a loop of rope or platelonge is passed around the coronet, below the fetlock, the free end being carried forward over the dorsal border of the neck, under the neck, towards its anterior border, and is then carried back under the same hind leg, between the hinder extremities and over the hock, from the posterior border, where an assistant, stationed at the back of the animal, is ready to receive it ([Fig. 1]). By careful, gradual and steady pulling upon the rope the foot is brought forward upon the external surface of the shoulder, and there secured by two or three turns of the rope around the coronet.
But it often occurs that in this position the inguinal region is not sufficiently exposed, and some of the steps of the operation may thus be rendered difficult, even when the surgeon has taken the precaution to pose the body of the patient and place him partly on his back, by means of bundles of straw pressed under the side upon which he lies. Many operators prefer the use of the double side line, with which, when the animal is thrown, both hind legs are brought forward together, and he is fixed squarely upon his back, and the inguinal region thus brought distinctly into view. The manipulation is thereby made easier for the surgeon, and, it is claimed, safer for the patient. The possibility of danger attending these methods has led many veterinarians in Europe, and in the United States as well, to prefer the operation with the animal in the standing posture. But it is to be considered that the same complications may rise in all instances, with the exception of apprehended injury to the vertebral column, which, though possible, is almost unknown, in fact, at the usual age of the castrated animal. It is to be considered, likewise, that the animal, on his feet, is free to struggle as violently as he wishes, and is thus exposed to the risk of the pulling and laceration of the spermatic cord, and a resulting predisposition to enlargements of that body and the formation of champignons. When it is considered, again, that by the traction of the cord the superior opening of the inguinal canal is necessarily dilated, and the formation of a hernia of castration is liable to take place, we submit the point to the intelligent judgment, whether, in the presence of these possibilities of extremely dangerous accidents, it does not become the duty of the veterinarian to prefer the mode of securing his patient in the supine position, both in his own behalf and that of his employer.
Fig. 2.
1. Testicular envelope. 2. Posterior serous septum. 2′. White muscular fibres of Bouley. 3. Serous membrane—portion of the tunica vaginalis. 3′. 3″. Visceral layers of the tunica covering the cord and the testicles. 4. The testicle with its peritoneal covering. 5. The epididymis. 5′. Globus major. 5″. Globus minor, the tail. 6. Deferent canal. 7. Spermatic blood vessels and nerves.
ANATOMY.
We now pass rapidly in review the anatomical structure of the inguinal region and of the testicular organs. A knowledge of these is of course essential to a proper understanding of the description of the various modes of operation, and of some of their sequelæ, upon which we shall soon enter.
The testicular envelopes, passing from the surface inwards, are represented by the scrotum, the dartos, the cellular coat, the tunica erythroida, formed by the cremaster, and the fibrous and serous or vaginal sac ([Fig. 2]). The scrotum is a continuation of the skin, and forms a complete bag, common to both testicles, which it contains and covers; the skin being here thin, vascular and nervous, usually black in color, almost hairless, and soft and unctuous to the touch. It is divided into two lateral halves by a raphæ or median line. It is very elastic, and easily yields to the efforts of distention, to which it is subjected, and when stretched over the organs it contains, presents a shining aspect, due to the sebaceous secretion which covers it. It easily contracts to its shrunken condition, and may be closely drawn up into the inguinal canal, when it assumes a thickly wrinkled surface.