Uterotubal insufflation (peruterine tubal insufflation) was devised in November, 1919, and was reported before this section in April, 1920, as a method of determining the fact of tubal patency without the necessity of resorting to a laparotomy.1It has since undergone several developments. The addition of manometric and volumetric control has made it possible to elicit diagnostic data that must escape the simple unaided introduction of gas through the uterus and tubes into the peritoneal cavity.2Within the past two years I have studied the behavior of the gas insufflation by means of an attached kymograph. It was manifestly desirable in view of the recent advances in our knowledge of tubal function to endeavor to see whether additional light might not be thrown on: The question of normal tubal patency, including tubal peristalsis. Interference with patency; i. e., stenosis or stricture. The question of spasm in individual cases.