SINCE 1886, when Hirschsprung1published a report entitled ""Sluggishness of the Stool in the Newborn, Resulting from Dilatation and Hypertrophy of the Colon," there have been many reports in the medical literature describing various aspects of megacolon. Generally, the name "Hirschsprung's disease" has been applied to the cases of megacolon reported in the literature but, as Finney2has pointed out, there were many reports of cases of megacolon in the literature antedating those of Hirschsprung. For this reason, in our opinion the descriptive term "megacolon" rather than the less precise eponym should be applied to these cases. Cases of megacolon are rarely encountered.3Perhaps as a result of the rarity of the condition, there have been few descriptions of the gross pathologic characteristics of megacolon. There have been a few reports4of single cases of megacolon in which the myenteric plexus was studied by microscopic pathologic methods. Except for the