Autopsy twenty-four hours after death. Upon opening the abdominal cavity, a large portion of the intestines was found of a dark purple or black color, while the remainder was perfectly natural in color. Upon lifting the bowels and exposing the mesentery, there was found an opening in the latter, of sufficient size to receive the thumb, and through which a large portion of the small intestines had become crowded, producing such a twist in the border of the mesentery as to have produced complete strangulation of the bowel, which had rapidly passed into a gangrenous state, resulting in violent shock and death in less than twelve hours. The opening was situated at about one inch from the intestinal border of the mesentery, and was plainly congenital in its origin, as indicated by its smooth and rounded edges.[21] Another form of obstruction is sometimes found, and known as =Volvulus=, in which a loop of bowel, generally of the small intestines, becomes twisted upon itself, the constriction at the base of the loop, finally resulting in complete closure. =Intussusception=, or invagination of the bowels, consists in the slipping of a portion of intestine into itself, and generally from above downwards. Either the large or small intestines may be found in this condition, but it is much more frequent in the lower portion of the small bowels. From a few inches to a foot or more of the bowel may thus become slipped into itself, and it may be found at more than one point. From the constriction which must necessarily attend such a displacement, congestion with hæmorrhage may result, or peritoneal inflammation, gangrene, and death, with symptoms of mechanical obstruction. In some rare cases, the inner or invaginated portion of the bowel sloughs off, adhesion takes place at the point of commencement of the intussusception, and the patient recovers. This form of displacement may be found in both children and adults, where the appearance of the parts are such as to render it apparent that it had not been a source of trouble during life. =Rupture= of the intestines may result from severe injury by blows, or from a crushing force applied to the abdominal walls. _Penetrating wounds_ of the bowels may be followed by escape of the intestinal contents into the peritoneal cavity, acute peritonitis, and death. If the bowel be empty at the time, adhesions may form between the adjoining parts, the wound thus closed, and recovery follow. _Prolapsus_ of the rectum consists in a protrusion of the mucous membrane or entire walls from the anus. The only post-mortem change that may be detected is a relaxed condition of the coats of the bowel, with congestion of the mucous membrane. =Diseases of the Anus.= These include _ulcer and fissure_ of the _anus_, _fistula in ano_, and _hæmorrhoids_.