_Below the Epididymis._--This, the fourth step of the operation, consists in the separation of the testicle from the epididymis and the torsion of one upon the other. The testicle being exposed, the operator, taking hold of its appendix, the epididymis, with the left hand, and of the gland with the right, their cellular serous attachment is divided by the thumbs from the posterior to the anterior extremity, from the tail to the head of the twisted efferent canal. If this cannot be done with the hand, the convex bistoury must be called into action. This accomplished, the head of the epididymis is firmly secured with the fingers of the left hand, and the right hand, left free, gives to the testicle the number of rotatory motions necessary to separate it from its excretory canal--that is, from eight to ten. When the testicle is thus severed, the stump of the end, with the epididymis, is pushed back into the vaginal sac, where it is confined by the application of a suture upon the middle of the edge of the scrotal wound. LIMITED TORSION. _Limited Torsion Above the Epididymis._--As we have seen, this is the operation by which the division of the spermatic cord is effected by torsion made upon a given point in its length, and limited by the use of special instruments. [Illustration: FIG. 3. FIXING FORCEPS FOR TORSION. A.--Renault and Delafond pattern. B.--Perier. C.--Reynal.] We have already called attention to the difficulty of the operation of free torsion, which requires a great deal of strength, and which, besides, may be accompanied by a serious inflammatory condition of the parts, through rough manipulations of the cord. It is for this reason that this mode of procedure must have been reserved for small animals, as, if performed upon the larger kinds, it can only be by men whose muscular force is sufficient to enable them to overcome and bring into subjection the struggling subjects of their operations. [Illustration: FIG. 4. MOVING FORCEPS FOR CASTRATION BY TORSION. Renault and Delafond pattern. Reynal pattern.] It was in 1883 that two French veterinarians, Renault and Delafond, of the Alfort school, introduced the use of instruments in the operation, as an improvement upon the manual methods and their effects on the sequelæ, though it is said to have been already practiced in Germany as far back as the last century. The instruments employed are two forceps of peculiar construction, and which were more or less modified, one of which (_fixing_ forceps, Fig. 3,) is to be applied upon a fixed point of the cord, where it is suffered to remain, and the other (_moving_ forceps, Fig. 4,) is employed to accomplish the rotation of the testicle and the lower end of the cord. Those of Renault and Delafond or of Reynal are now in general use. Those of Beaufils (Fig. 5) are, we believe, too complicated for general use. [Illustration: FIG. 5. COMBINED FORCEPS OF M. BEAUFILS.]