Of all the operations pertaining to the domain of Veterinary Surgery, without doubt the practitioner is most frequently called upon to perform—more especially in breeding districts—that of castration, the destruction or removal of the essential organs of generation in our domesticated animals. It is, however, not nearly so often resorted to for purely surgical reasons as for purposes closely related to questions of agricultural and industrial economy, by reason of its effect upon the individuals of the various species of animals subjected to it, in order to improve their value and increase their usefulness to mankind. And that this is its practical effect is no modern discovery. As far back in antiquity as seven centuries preceding the Christian era, it was known and practised upon various animals. Of this we may find ample historical proof in the writings of Roman, Greek, and Oriental authors, where specific mention appears of the various methods employed, including the processes of excision, of crushing and of tearing. Even the castration of females was known to our less remote ancestors, the Danes having in the sixteenth century performed it on sheep, swine, cows, and even mares. The spaying of cows, however, seems to have been forgotten about the beginning of the present century, and it was not until the year 1831 that Thomas Winn, of Natchez (Louisiana), and afterwards Levrat (of Lausanne), brought it to the attention of veterinarians, as a means for the improvement of the milky secretion in cows.

The operation may be considered under two distinct heads. Under the first it is to be considered as one of necessity, as when performed with a therapeutic object in view; as, for example, when it constitutes one of the first steps involved in the surgical treatment of strangulated hernia, or of diseased conditions of the testicles or ovaries, such as orchitis, epididymitis, sarcocele, hydrocele, cyst, etc. In the other case it is resorted to for reasons of mere fashion and convenience, and has for its object the production of such a modification of the general organism as shall increase the adaptedness of the animals subjected to it to the uses to which they are applied; when, of course, the economic becomes the paramount and exclusive reason for thus interfering with the obvious creative purpose. It is the operation as performed under this general heading that we shall now principally consider.

In relation to this latter object it must be borne in mind that the operation is followed by certain peculiar effects, which may either manifest themselves upon the entire organism, or upon some special functions only. In the first instance it is quite evident that the primary and most obvious effect of the mutilation is to be discovered in the character and disposition of the animal, which at once becomes in a double sense an “altered” creature, docile and submissive, and entirely willing to become the obedient and useful servant of his human master. But it is not alone that we find the vicious stallion, the uncontrollable bull, the kicking jackass, the dangerous boar, and even the hysteric mare and cow transformed into the useful gelding, the quiet ox, the patient donkey, and the “fatherly” barrow, the quiet working mare and the productive cow, as the result of the change which the character—the nervous system, in fact—has undergone. Besides this, other marked changes are to be observed of a more distinctly physical character, such as a modification of the entire organism, manifested in the external symmetry, and the expressive physiognomy of the creature, when deprived of its virility.

The animal becomes more quiet, and its general form is modified. If altered at an early age, the skeleton will be arrested in its growth, and the mass of muscles attached to it will participate in the defective development; the head will become elongated, the legs will continue to be lighter, and the body will show a corresponding lack of development. In other words, the male animal will tend to assume the characters of the female, in form and feature, the gelding, indeed, resembling the mare, not only in the ensemble of his appearance, but in his voice, which loses the resonance of the stallion’s, and his physiognomy, which becomes milder and less expressive; while his neck is lighter and his mane more scanty, with the hairs which compose it more fine and silky.

A like tendency exists in other male animals to acquire a resemblance to the female as an effect of the operation of castration. The altered bull has a weak and feminine voice; his head is narrower and elongated; his horns become lengthened and more curved; he has exchanged his wild and threatening aspect for a mild and gentle visage; his neck also is lighter and his chest narrower; his bony structure is less massive; and he has, besides all the rest, acquired a quality of essential importance to mankind in a dietetic view, that of accumulating fat. This last phenomenon shows us that besides the other changes referred to, there is an important modification of the nutritive forces of the animal, or at least a change in the direction of their action.

When thus deprived of his virile functions the animal ceases, in effect, to exist as one of a species, but maintains an essentially individual life, in which the assimilable nutriment which he absorbs, instead of being in part appropriated to the office of reproduction of his kind, is all devoted to his own individual conservation. In animals not used for draught purposes, or in other labor, when the food received is nearly always in excess of the amount required for the support of the organism, the result follows that the surplus of nutritive substances (found sometimes in great abundance) becomes stored in the connective tissue and intermuscular structure, and that in this way the flesh assumes superior and more nutritious qualities than that of the unaltered animal, while, at the same time, it loses the strong and peculiar odor frequently communicated to it by the presence of the testicular apparatus and secretion in the entire animal.

This property of modification of function is probably still better illustrated in the effect of the operation upon cows, where we shall find not only the power of accumulation of fat increased by castration, but, above all, the milky secretion improved both in quality and quantity, and also in the duration of the flow.

AGE.

The question, “at what age can an entire animal be altered?” admits of a simple answer, to wit, “as soon as the testicles can be easily reached—as soon as they appear outside of the abdominal cavity, and are found in the inguinal canal.” But although it can be performed at that epoch, or deferred to any period of after life, it must be remembered that it is easier and less dangerous in young than in older animals, and that with the former it is a simple operation, producing, ordinarily, no noticeable alteration in the other functions, and but rarely followed by accidents.

A period between eighteen months and two years is generally preferred for horses, though, according to some authors, even a much earlier date may be chosen, some English veterinarians being accustomed to operate at as early a date as ten days from birth. It is immaterial, however, at what precise time the operation may be performed, since it is a conceded point that the earlier it is done the better.

SEASON.

When it is possible to choose the season most favorable for the operation, and for securing the best chances of recovery, the spring, or the early stages of the fall, are those to which the operator should give the preference, provided the atmospheric temperature is moderate and not susceptible to sudden variations. It is to be remembered that at some periods of the year, without any known or apparent cause, a tendency appears in wounds to take on gangrenous or septicemic complications which are not so generally observed in the mild weather of spring and early fall. Another essential condition which surgeons will do well to take into consideration is the general health of the subject, as in all cases of surgical interference, any diseased tendency already existing (perhaps latent) in the patient, such as an anÆmic condition, a gourmy predisposition, or typhoid susceptibility are likely to give rise to the development of serious and perhaps fatal sequelÆ to an operation which, simple as it may be in itself, is nevertheless not without danger, or of possible complications of its own.

PREPARATIONS.

The preparations to which the animal is to be subjected previous to undergoing the operation are the same as those which are required in other cases of surgical manipulation. Some portions of the preparations are, perhaps, of even greater importance, and may not, on any account, be overlooked, when we take into consideration the peculiar position in which the animal must frequently be secured in order effectually to control his movements. Hence, a low diet for twenty-four hours preceding that appointed for the operation, and an empty stomach at the time of castration, with a thorough washing of the sheath, are precautions which no surgeon entitled to the name will overlook or neglect, especially when a soliped is to be subjected to the knife. We shall discuss hereafter the indications in the case of the castration of large females.

RESTRAINT.

Two modes of restraint are employed in securing the animals during the manipulations for the removal of the testicles, one which is applied to all the various methods yet to be described, and the other applicable principally to the method of amputation of the cord by the use of the Écraseur. In the former, the animal is thrown down and secured with one of his hind legs fixed in a position in which the inguinal region is fully exposed. In the latter he is allowed to remain in a standing posture, and is kept quiet by the application of a twitch upon his upper lip. As the first mode of securing the patient is the safest for all parties engaged in the undertaking, and from the further fact of its applicability in all methods of operating, we shall first consider it somewhat in detail.

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.

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.

The second envelope, the dartos, is a prolongation of the tunica abdominalis, and is a yellow, fibrous structure, forming two distinct sacs resting upon each other, and lying on the inside of the scrotum, to which it is intimately adherent.

In the lateral and superior parts the adhesions are looser, and in front it becomes continuous with the suspensory ligament of the sheath, which, like itself, forms a portion of the abdominal tunic. Under the dartos is a layer of very loose cellular tissue, the lamellÆ of which are so formed that it may be divided into several superimposed layers. This formation endows the testicle with great mobility in the dartoid sac; and these layers may be easily separated with the finger from the external surface of the fibrous coat beneath, except posteriorly, where it forms a strong band which sometimes requires even the aid of an instrument to divide.

The next envelope is represented by the tunica erythroida which is the cremaster muscle, and from the lumbar region extends itself downwards into the inguinal canal along the outside of the cord, and terminates towards the superior part of the testicle in fibres spreading only over its external face. This muscle, by its deep surface, rests upon the fibrous coat—another envelope of the testicle and of the cord—and to which it is closely adherent. To the powerful contraction of this muscle is due the retraction of the testicle into the depth of the groin, which condition sometimes it is so difficult to overcome in the first stages of the operation.

The fibrous testicular envelope which we have just seen giving attachment to the cremaster, is a thin membranous bag, elongated like the neck of a bottle around the spermatic cord, which it envelopes, and dilated below, in order to enclose the testicle. Lined internally by the serous coat, to which it intimately adheres, this last membrane is a duplicature of the peritoneum, drawn downwards by the testicle when it descends from the abdominal cavity into the inguinal canal. This serous envelope has, therefore, two coats, one lying on the inside of the fibrous tunic, and called the parietal, and that which covers the cord and the testicle and is known as the visceral. These two layers approximate towards the posterior border of the cord, and, as they unite, form a sort of fold, band, or septum which divides into two parts the posterior portion of the vaginal cavity, and becomes a means of solid adhesion between the tail of the epididymis and the bottom of the sac.

The testicles, thus covered by the visceral layer of the serous coat, are suspended at the end of the spermatic cord, and surmounted upon their superior border by the epididymis, the first part of the deferent canal, which is folded upon itself, while at its posterior extremity—the “tail,” so called—it continues in a straight course, and conveys the product of the secretion of the testicles into the vesiculÆ seminales, lodged in the pelvic cavity.

The spermatic cord is formed anteriorly by the spermatic or great testicular artery, which forms, in that portion, a large number of flexuosities, causing its length greatly to exceed that of the cord to which it belongs. It contains a network of veins, and lymphatic vessels in abundance, which are united to the curves of the artery by a somewhat loose cellular tissue. A large number of nervous branches, given off by the solar plexus, surrounds the whole.

Between the lamellÆ of peritoneal structure which forms the posterior septum, and which unites the parietal with the visceral layer, there is found a band of grey muscular fibres—first discovered, I believe, by H. Bouley—which exerts a powerful agency in the retraction of the testicle towards the inguinal ring. Behind this muscle, and situated on the internal face of the septum, are found the deferent canal and the circumvolutions of the small testicular artery.

Having thus considered the essential points of the anatomical structure of these organs, we shall next seek to enforce the importance of their careful study in reference to the intelligent and skilful performance of the important operation which we are discussing.

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