_Preparation of the animal._--No general preparation is required, except one, which may be regarded as of local effect, but is not to be overlooked. This consists in the evacuation of the bowels by means of a rectal injection, in order that the arms of the surgeon may not become unnecessarily soiled during the operation. The animal is secured on her feet by being placed in a narrow stall to prevent her from moving from side to side, the floor of the stall having an inclination forwards, in order to prevent the pressure by gravitation of the intestinal mass towards the posterior parts of the abdomen. The operation is completed in two steps, of which the first is the incision of the vagina, and the second the extirpation of the ovaries. THE INCISION IN THE VAGINA. This is made in the following manner. The operator introduces the speculum with his right hand, through the vulva, into the vaginal cavity, and carefully passing in his left hand, well oiled, directs and introduces the little prolongation A of the speculum into the centre of the neck of the uterus, gently pressing upon it in order to keep it in place. In using the original dilator, the opening of the branches must be so regulated as to put the walls of the vagina upon the stretch. Or, if he uses the modified speculum, he pushes the instrument downwards and forwards, and by this motion distends the upper wall of the cavity, keeping the instrument in that position by a hold of the left hand, which has been withdrawn from the vagina. He then arms himself with the bistoury caché, which he holds closed in his full hand and introduces with the right hand into the vagina. Carefully feeling the condition of the upper wall of this cavity, and assuring himself of its being well stretched, he rests his hand, still holding the bistoury, upon the opening or “window” at the end of the speculum (Figs. 37 and 38), and by firmly pushing the blade (the sharp edge being turned backwards) out of its handle, pierces with it the vaginal walls, about two inches above the neck of the uterus, and with a motion from below upwards and from before backwards, makes an incision on the median line, from three to three and a half inches in length. The introduction of the instrument must be made in such a manner that it will pass at once through the walls of the vagina proper, as well as through the peritoneal cap which it presents at its anterior portion. The incision being completed, the speculum is carefully withdrawn; and if a slight hemorrhage should occur, the blood should be removed before the surgeon proceeds to the second step of the operation. [Illustration: FIG. 37. CASTRATION OF COWS. (Charlier’s process). Incision of the vagina.] [Illustration: FIG. 38. CASTRATION OF COWS. (Charlier’s process). 1st step. Incision of the vagina.] [Illustration: FIG. 39. SCISSORS DIVIDING THE BROAD LIGAMENTS.] REMOVAL OF THE OVARIES.