From the Karolinska Hospital, Stockholm

I do not intend to give an account of the changing philosophies concerning the aetiology and treatment of the disease which followed upon Hirschsprung's (1888) first presentation of it as an entity in 1886. It required about 60 years of vague or wrong ideas to find the key to our present knowledge. That happened when our attention was diverted from the characteristic megacolon and was focused on a less conspicuous and apparently normal distal part of the bowel. In 1946 a study of the early stages of the disease in 10 newborn infants (Ehrenpreis, 1946) revealed that the megacolon was not present at birth but developed only secondarily. Hirschsprung's (1888) assumption that constipation was caused by con-genital megacolon could thus be reversed: the megacolon proved to be caused by the congenital constipation. During the next few years definite proof of the cause of congenital constipation was presented. Evidence was produced that a narrow or normal-looking segment of rectosigmoid distal to the dilated colon was the primary pathology in Hirsch-sprung's disease (Swenson and Bill, 1948). Neuro-histological investigations demonstrated that the entire distal segment lacked ganglion cells (White-house and Kernohan, 1948; Bodian, Stephens and Ward, 1949; Swenson, Rheinlander and Diamond, 1949). Removal of the distal segment cured the disease (Swenson and Bill, 1948). Finally, a most important advance was made by the subdivision of the group of idiopathic megacolon into two different disease entities (Bodian et al., 1949). Only about half of the cases of idiopathic megacolon showed the clinical, radiological and neurohistological signs which had been demon-strated as typical of Hirschsprung's disease. The other half disclosed a different pattern of symptoms and signs, the main diagnostic difference being the absence of a distal aganglionic segment (Figs. 1-2). This division has made it possible to account for the * A paper given at the inaugural meeting of the British Associatio