The Mechanics of the Digestive Tract, Fourth Edition: An Introduction to Gastro-Enterology provides information pertinent to the mechanics of the digestive tract. This book reviews the various explanations for the downward progress of intestinal waves. Organized into 34 chapters, this edition begins with an overview of the main types of activity in the small bowel. This text then explains the nature of the polarity and the location of the mechanism that produces it. Other chapters consider the duodenal tonus contraction in which the wave seems to originate generally appears a few seconds before a gastric wave reaches the pylorus. This book discusses as well the polarity of the bowel that caused every contraction ring to spread caudad as soon it formed. The final chapter provides a list of books that are likely to be helpful to readers who are starting on their lifework in the fields of gastro-enterology and gastro-intestinal physiology. This book is a valuable resource for students, teachers, physicians, and research workers.