1. _Colotomy in the left loin_, generally known by the name of _Amussat's operation_.--The patient is laid upon his face, a pillow placed under the abdomen, rendering the left flank prominent. A transverse incision should then be made at a level about two finger-breadths above the crest of the ilium, extending from the outer edge of the erector spinæ muscle forward for four or five inches, according to the fatness of the patient; the muscles must then be carefully divided till the transversalis fascia is exposed. It is then to be pinched up and divided, as in the operation for strangulated hernia. The muscular wall of the colon uncovered by peritoneum is then in most cases very easily recognised from its immense distension. The bowel should then be hooked up by a curved needle, two or three points at least secured to the margins of the wounds by stitches, and then the bowel should be opened by a longitudinal incision of at least an inch in length. When the distension has been great, there is generally a rush of fluid fæces, which must be provided for, special care being taken lest any get into the cavity of the peritoneum. [Illustration: FIG. XXXIII.[149]] 2. _Colotomy in the left groin_, for absence of anus and deficiency of rectum in newly born infants.--The dissections of Curling, Gosselin, and others have shown that in infants the operation of lumbar colotomy is very difficult, and its results uncertain, while it is comparatively easy to open the colon in the left groin. Huguier, again, has shown that in certain cases the colon is not to be found in the left groin, but is accessible in the right groin. This abnormality seems, as shown by Curling, to occur not oftener than once in every ten cases. _Operation._--An oblique incision from an inch and a half to two inches in length should be made in the left iliac region above Poupart's ligament, extending a little above the anterior-superior spinous process of the ilium. The fibres of the abdominal muscles should be divided on a director passed beneath them, and the peritoneum should next be cautiously opened to a sufficient extent. The colon will most likely protrude, but if small intestine appear the colon must be sought for higher up. A curved needle armed with a silk ligature should be passed lengthways through the coats of the upper part of the colon, and another inserted in the same way below, and the bowel, being drawn forwards, should then be opened by a longitudinal incision. The colon must afterwards be attached to the skin forming the margin of the wound by four sutures at the points of entry and exit of the needles.