This mode of castration consists in the application to the cut end of the testicular cord--previously divided with the bistoury, or by the cautery--as a means of hemostasis, of an iron heated to a white heat--the actual cautery. This is claimed to be one of the oldest modes of operating, Vegetius and Absyrtus describing it as a common process of castration. It is much in favor in England, and in some parts of Germany, though less practiced in some other parts of Europe. The instruments essentially needed for the operation of castration by firing are two; the first, a peculiar forceps for holding the cord and securing it while the application of the cautery is being made; and the second, the iron or cautery itself. [Illustration: FIG. 9. SINGLE FORCEPS FOR CASTRATION BY FIRING.] [Illustration: DOUBLE FORCEPS FOR CASTRATION BY FIRING.] These forceps, or nippers, are either single or double (Fig. 9), and may be made either of wood or of iron, and more or less modified in form, according to the fancies of the different operators. But they all work on the same principle, and effect the same object. With the single forceps but one cord can be treated at a time, but with the double instrument both cords may be secured at once, and may be divided and cauterized at one step. In this way the possibility of disturbing the eschar caused by the cauterization of one cord while manipulating the second, is quite obviated. When the testicles, either or both, have been exposed, the mass of the cord is fixed between the jaws of the forceps, from before backwards, at about one inch above the tail of the epididymis, and firmly secured. This may be effected either by tying it tightly with a string wound about the handles, or by means of a spring crank with which some instruments are furnished. The testicle is then amputated, either by a stroke of the bistoury, or with the sharp edge of the cautery carried across and at a right angle with the direction of the cord. This done, the operator applies the broad portion of the iron over the entire surface of the stump of the spermatic cord, and cauterizes (or sears) the part thoroughly. It must be remembered that to insure the safety of the cauterization, the iron must be very hot. Otherwise, when it is removed, if it has cooled off, it may adhere to the carbonized surface, and the scab formed at the end of the blood vessel may accompany the instrument. The application of pulverized rosin to the end of the cord, previous to the cauterization, is recommended by some practitioners. A very proper precaution, and one on no account to be omitted, is the protection of the surrounding parts from the radiating heat by covering them with wet cloths.