Abstract
1. Inhibitory response to nicotine was observed in fresh intestinal preparations isolated from chicks 1 week to 3 months of age, and only contraction in fresh intestinal preparations from adult domestic fowls. 2. The inhibitory action of nicotine was enhanced after cooling. Even in intestinal preparations from adult fowls, inhibitory response appeared frequently. 3. The inhibitory nicotine response to the intestinal preparation was supposed to be due to stimulation of ganglion cells, as it was abolished by hexamethonium. 4. Existence of two kinds of functionally distinct fibers in the myenteric plexus was revealed also in the avian intestine. When stimulated, one caused contraction and the other inhibition of the intestinal Movement. 5. The differential development of such two kinds of functionally antagonistic fibers in the inner plexus was suggested.
