Abstract

1. Morphine sulfate in doses of 16 or 48 mgm. injected subcutaneously in dogs weighing from 19 to 36 kilograms causes an increase in tone and in propulsive and non-propulsive motility of the colon.

2. Fifty per cent of the propulsion of large magnitude occurs in the first 20 minutes after the subcutaneous injection of 16 mgm. of morphine sulfate.

3. The previous injection of 1 mgm. of atropine will antagonize the propulsive activity produced by 16 mgm. of morphine sulfate, but has slight temporary effect, if any, on tone and non-propulsive activity.

4. One milligram of atropine will antagonize both the propulsive and non-propulsive activity initiated by 4 mgm. of morphine sulfate.

5. One milligram of atropine depresses the spontaneous motility of the colon of the dog for a variable length of time (1 hour to several hours). The distal colon is depressed for a longer interval of time than is the proximal colon.