The divisions of the left bundle anastomose so freely with each other in the mesentery and immediately above the intestine that the blocking of any one branch cannot entirely arrest the circulation in the corresponding part of the intestine. It may however produce a partial local stagnation in the vessels of a short loop of intestine, resulting in œdematous infiltration and thickening with resulting induration and stricture of the gut. Chronic and permanent lesions are produced by such blocking, but only rarely acutely fatal ones. Acute and fatal congestive lesions of the small intestine from verminous embolism, occur only when several adjacent divisions of the artery are blocked at once, and this is a rare occurrence. The right bundle of branches furnishes the only two arteries which are supplied to the cæcum and the only artery furnished to the first half of the double colon. The ileo-cæcal branch is less involved, first, because being less dependent and smaller, it is less likely to receive an embolus, and, second, because any lack of blood supply is counterbalanced by the free anastomosis with the last iliac division of the left bundle. When the embolus blocks the undivided trunk of the right bundle this same principle comes into play, the free supply of blood from the posterior branch of the left bundle supplying blood through its anastomosis with the iliac and cæcal branches of the right. But when the emboli are lower down, in the cæcal branches of the right bundle, or in these and the colic branch, arrest of the circulation in the intestinal walls ensues, followed by paresis, passive congestion and hemorrhage. The cæcum and double colon thus become the seats of the grave and fatal lesions of verminous embolism. The resulting lesions are to be variously accounted for. The stagnation of blood in the vessels below the embolus, determines a speedy exhaustion of its oxygen and increase of its carbon dioxide, so that it is rendered unfit to maintain the normal nutrition and functions of the part, and the capillary and intestinal walls are alike struck with atony or paresis. The blood filters into the stagnant vessels slowly from adjacent anastomosing trunks, and the liquor sauguinis exudes into the substance of the tissues and lumen of the intestine, leaving behind the greater part of the blood globules so that the stagnant blood is rendered more and more abnormal in composition. The walls of the capillaries soon lose their cohesion as well as their contractility, and giving way at different points, allow the escape of blood into the tissues, bowels and peritoneal cavity. It has been further claimed that the emboli already infected and in process of degeneration communicate this to the walls of the vessels and to the stagnant blood, hastening the process of degeneration and rupture.