Abstract
The movements of the gastrointestinal tract, as described by Walter B. Cannon 100 years ago, reveal much about the functions of this unique organ and how it is controlled by the body. Two classic papers by Cannon provide a rare glimpse into the hidden functions of the body and give students a great example of the scientific method in action. In this essay, we describe the basic movements and functions of the gastrointestinal tract as revealed by X-rays, contrast meals, and Cannon's careful observations. It is Cannon's experimental care and obvious interest in his subject matter that can provide your students with a taste of the excitement of discovery and insight into the processes by which experimental science moves forward.