The necessity of this operation, at least so far as the British Islands are concerned, is its justification. There are not wanting extreme humanitarians who are prepared to deny the necessity of castration, and point to the fact of entire animals being employed to a considerable extent in European capitals. In the omnibuses of Paris, stallions are commonly found yoked together, and apparently upon good terms with each other. In this country it has been proved dangerous and inconvenient to employ them for such purposes. We may claim, too, that the custom of castration having been general for centuries, has tended to the survival of the fittest, and that being so, our horses are in every respect superior to those of other countries, and being more high-spirited, are consequently dangerous for general use when not emasculated. It is obvious that breeds cannot be maintained pure if at pasture the sexes are permitted to associate, and the inconvenience of having to keep them apart on an ordinary farm holding-would very materially interfere with horse-breeding. In the town stable a similar objection applies, notwithstanding that certain mechanical restraints are employed to keep mares apart and stallions from fighting.
Castration in some crude form would seem to have been a means adopted very early in the history of the world, not only for the purposes of taming and controlling animals used in the service of man, but also for improving their flesh. In the Pentateuch we have references to animals "maimed, broken or lacking in their parts", and a very distinct one to mulling1 as still practised in Asia.
Age. - It is usual in this country to castrate yearlings, provided the colt has wintered well and developed sufficiently in the forehand. There is much to recommend this custom, inasmuch as the animal may continue after operation to run with other horses. It is, however, found that some considerable number of colts are not fit for operation at this age, for the reason that only one testicle is to be seen in the scrotum, the other not having made the second descent (they are both usually present at birth). It is then advisable to wait until autumn or perhaps until the following spring. Castration is also postponed until the second year when colts me low at the wither, light or of ewe-formation in the neck, or generally backward in development, or where it is desired to have male features more pronounced. For the last reason, operation may be deferred until the third season, when all the inconveniences of keeping an entire horse are of course encountered. When the operation is too long deferred the shoulders become thick and heavy, the crest high and coarse, and the forehead broad; in a word, the masculine features which distinguish the horse from the gelding become developed.
These are many, and vary not only in different countries, but also in counties and districts of England. Some are practised while the animal is upon his feet; others necessitate casting with hobbles or ropes.
The oldest, and what is still regarded by many expert operators as the best method, is by actual cautery. Hobbles of various designs (see Methods of Restraint) are employed by some operators, while others attain their object with no other apparatus than a wagon rope (see Plates LI and LV).
The colt being cast upon his left side, and the hind-limbs drawn forward out of the way of the castrator, the parts are fully exposed. The penis and scrotum are now thoroughly cleansed with soap and water, and freely anointed with carbolized oil or vaseline, so that in the event of any considerable swelling following the operation, the penis may be extruded without difficulty in the act of urination. While this is being done, the scrotum is examined for possible hernia or malformation, and having satisfied himself that all is normal, the operator seizes the testicle in the left hand, and drawing the skin tightly over it, proceeds to lay open the scrotum with a bold long sweep of the knife (fig. 516), which shall by one stroke divide the common integument and investing membranes. He will choose the under testicle first, as the second operation will not then be so much obscured by blood as when the reverse order is pursued. The gland, having been freed from the purse, is firmly grasped, and the action of the cremaster muscle, which tends to draw it back again into the scrotum, is steadily resisted. Any attachment which may be found to exist between the testicle and the investing membrane is divided by the knife, until the gland is clear of everything but the cord. A clamp or forceps made for the purpose (fig. 518) is then placed upon the latter, and either locked by a hook or serrated catch at the end, or firmly held by the operator, while in the right hand he holds a red-hot iron, with which the cord is divided by a gentle sawing movement of the instrument.
1 Levit. xxi. 20: "or having his stones broken". Deut. xxiii. 1.
HORSE CAST FOR CASTRATION.
A " D " or a Spring Hook must be inserted at * to prevent the chain from slipping.
To prevent haemorrhage from the spermatic artery a little powdered resin is dusted on to the divided extremity of the cord, and a somewhat cooler iron is then employed to seal up the vessel.
The majority of castrators employing this ancient but truly aseptic method also adopt the precaution of smearing the clamp, and afterwards anointing the interior of the purse with an ointment composed of verdigris, Venice turpentine, and bees'-wax, with the object of preventing too rapid healing of the wound and imprisonment of blood-clots, which may decompose and set up septic poisoning.
Fig. 516. - Castrating Knife.
Fig. 517. - Castrating Iron.
Fig. 518. - Clamp for Castration by Firing.
Whatever the origin of the custom, we know that verdigris (copper acetate) is a valuable antiseptic, and that the success of this apparently crude application of the antiseptic system is beyond dispute. The method above described is that most commonly practised among those who employ the actual cautery and cast horses as a preliminary to castration, but the details vary, and some operators do not use a knife at all, but divide the coverings of the testes by a thin-edged and very hot iron. Dexterously carried out, this is not so painful as from the bare recital of the method it would appear, the severance being very rapid when the investitures are rendered tense by the hand or clamps grasping the scrotum below.
Haemorrhage from the spermatic artery when imperfectly sealed is the chief danger to be feared; a moderate amount of bleeding from the small vessels divided is rather welcomed as presaging less swelling subsequently. Un the completion of the operation the inner aspect of the thighs should be anointed with lard or vaseline to prevent scalding of the skin by matter discharged from the wounds in the course of healing, and it may be advisable to tie up the tail when long, lest the decomposing blood and matter gathered upon it be transferred to the wounds and set up septicaemia or blood poisoning. This is especially liable to take place in summer, when flies are troublesome and the tail is lashed between the thighs to effect their displacement.