Dilatation of the colon frequently occurs as a transient affection, and by its action in pushing up the diaphragm may so seriously interfere with the action of the heart and lungs as to occasionally cause heart-failure. Fenwick has mentioned an instance of this nature. According to Osler there is a chronic form of dilatation of the colon in which the gut may reach an enormous size. The coats may be hypertrophied without evidence of any special organic change in the mucosa. The most remarkable instance has been reported by Formad. The patient, known as the "balloon-man," aged twenty-three at the time of his death, had had a distended abdomen from infancy. Postmortem the colon was found as large as that of an ox, the circumference ranging from 15 to 30 inches. The weight of the contents was 47 pounds. Cases are not uncommon in children. Osler reports three well-marked cases under his care. Chapman mentions a case in which the liver was displaced by dilatation of the sigmoid flexure. Mya reports two cases of congenital dilatation and hypertrophy of the colon (megacolon congenito). Hirsohsprung, Genersich, Faralli, Walker, and Griffiths all record similar instances, and in all these cases the clinical features were obstinate constipation and marked meteorismus. Imperforate Anus.--Cases in which the anus is imperforate or the rectum ends in a blind pouch are occasionally seen. In some instances the rectum is entirely absent, the colon being the termination of the intestinal tract. There are cases on record in which the rectum communicated with the anus solely by a fibromuscular cord. Anorectal atresia is the ordinary imperforation of the anus, in which the rectum terminates in the middle of the sacral cavity. The rectum may be deficient from the superior third of the sacrum, and in this position is quite inaccessible for operation. A compensatory coalition of the bowel with the bladder or urethra is sometimes present, and in these cases the feces are voided by the urinary passages. Huxham mentions the fusion of the rectum and colon with the bladder, and similar instances are reported by Dumas and Baillie. Zacutus Lusitanus describes an infant with an imperforate membrane over its anus who voided feces through the urethra for three months. After puncture of the membrane, the discharge came through the natural passage and the child lived; Morgagni mentions a somewhat similar case in a little girl living in Bologna, and other modern instances have been reported. The rectum may terminate in the vagina. Masters has seen a child who lived nine days in whom the sigmoid flexure of the colon terminated in the fundus of the bladder. Guinard pictures a case in which there was communication between the rectum and the bladder. In Figure 140 a represents the rectum; b the bladder; c the point of communication; g shows the cellular tissue of the scrotum.