Although sporadic reports of absence of ganglion cells in Auerbach's plexus in the rectum of patients having Hirschsprung's disease began to appear as early as 1901, and although a detailed description of 11 such cases by Whitehouse and Kernohan in 1948 firmly established the association of the aganglionic terminal segment of the large bowel with megacolon, it remained for Swenson and his associates,7 followed closely by Bodian, Stephens, and Ward, and by Hiatt,2,3 to analyze the significance of this finding and to utilize the information clinically. They concluded that the disease could be explained by the assumption that the aganglionic distal part of the colon obstructs the passage of feces. Megacolon results from this chronic obstruction; the aganglionic portion does not become dilated. A colostomy made in the dilated portion of the colon functions normally; if such a colostomy is closed surgically, obstipation recurs. Studies of motility of