For these subjects, two modes of operation are to be principally recommended. The first is the double subcutaneous torsion; the other the ligature _en masse_ of the cord and its envelopes. Having already considered these operations, a passing reference will suffice here. FOR SWINE. In _males_, the varying modes employed are the ligature, limited torsion, and the clamps. [Illustration: FIG. 41. GENITAL ORGANS OF A YOUNG SOW. (Median and antero-posterior section). 1--Ovary. 2--Horn of the uterus. 3--Body of the uterus. 4--Rectum. 5--Vagina. 6--Bladder. 7--Kidney. 9--Intestines. 10--Stump of one of the horns of the uterus.] [Illustration: FIG. 42. BISTOURY FOR THE CASTRATION OF SOW. (Division of the flank).] In _females_, it must be remembered that the horns of the uterus are very long and flexuous (Fig. 41), and that the very small ovaries are situated on the inside of the broad ligaments, which are very large, and allow the horns to float freely amongst the circumvolutions of the intestines. The animal must be prepared by being secured upon the right side in order to expose the left flank. The incision is made with a knife of peculiar form (Fig. 42), the coarse bristles having been previously closely clipped off. Care should be taken to carry the left leg in extension backwards, in such a manner that the edges of the various tissues divided shall not meet each other when the operation is completed. The incision may be made either vertically, horizontally, or obliquely. When vertical it should be immediately below the lumbar vertebra next to the last rib; if horizontal it should be parallel with the vertebral column. The vertical incision should be preferred, because it brings the ovaries within easy reach of the fingers. It should be from two to three inches in length, and should be made by a single stroke of the knife, and without dividing the peritoneum, which should, afterwards, be either torn with the finger or carefully cut while raised with the forceps. To find the ovaries the operator introduces the index finger of the right hand between the vertebral column and the intestines, and explores the lumbar region. Upon finding the ovarian sac, he presses it against the abdominal wall and causes it to slide by pushing towards the opening through which it is extruded and grasped. While it is held there the left horn is carefully drawn out after it, until arriving at the bifurcation of the horns at the uterus, the right horn also is brought out and the ovary on that side secured. Both glands being now outside, they are torn or scraped off from their attachment, and the horns are returned to the abdomen.