A vast and growing literature on diaphragmatic hernia, larger than the incidence of the condition would seem to warrant, attests a keen interest in this condition. Once rated as extremely rare, it is now considered more often among diagnostic alternatives because of the publicity it has received and the increasing frequency with which these hernias are being discovered. For example, as late as 1924 it was estimated that in all not more than 1,200 cases had been recorded, but these consisted chiefly of gross and easily demonstrable hernias, and since that time, besides numerous single case reports, several extensive series comprising less obvious cases have been added. When this estimate was made, only twenty cases had been listed at the Mayo Clinic, but during the last six years ninety additional cases have been observed in this clinic alone. It is evident, therefore, that diaphragmatic hernia is not merely a pathologic