While investigating the degree of intra-intestinal pressure in simple obstruction,1 a method was employed which was thought to give a fairly exact conception of the type and magnitude of the intestinal motility. The degree of pressure was found to be maintained at a level (from 6 to 8 cm. of water) about twice that of the normal maximum (from 2 to 4 cm. of water), and when the intestine became active, the pressure rose to ten or fifteen times the normal (from 30 to 60 cm. of water). Having determined the type of motor activity and the degree of intra-intestinal pressure in this condition, it was concluded to record the effect of certain tissue extracts and drugs on the movements of obstructed intestine and on the intra-intestinal pressure.. For the most part, the action of a drug on smooth muscle, such as is found in the intestine, is usually