The presence of a toxic substance within the lumen of the bowel in cases of intestinal obstruction has long been recognized, but the process by which it enters the system, if indeed it is absorbed, is a problem that is as yet unsolved. The observations of Stone and Firor,1 in 1924, suggested the possibility that the changed intra-intestinal pressure might alter the intestinal permeability. Without attempting to investigate the latter problem, it appeared that a study of the degree of pressure within the lumen of the bowel during obstruction might be undertaken with profit.
Before attempting to determine the abnormal conditions, it was necessary to find out the normal intra-intestinal pressure and the relationship of the intra-abdominal pressure to that within the intestine. The physiology of the gastro-intestinal tract from a mechanical point of view reveals an extremely complicated conducting system. The stomach, serving as a reservoir, must receive