Pain is, perhaps, the most important evidence on which we base our interpretation and diagnosis of abdominal disease. So whatever contribution may be made to the better understanding of abdominal pain, its origin, nature, and localization, is of direct interest to the clinician. Our present knowledge of sensation in the abdomen and its viscera is due largely to the careful and ingenius observations during laparotomies of Lennander1and Sir James Mackenzie.2These observers are agreed that the hollow viscera and omentum give no sensation response to heat or cold, to cutting or clamping. Lennander found that the parietal peritoneum was sensative to irritation, especially when inflammation was present. This pain sense he explained by the rich supply of cerebrospinal nerves to the parietal peritoneum and its subserosa, in contrast to the sympathetic nerve supply of the insensitive viscera. From these premises he contended that all visceral pain was the result