CONDUCTION IN DIFFERENT PARTS OF THE SMALL INTESTINE

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Abstract
The small intestine of rabbits was stimulated with a faradic tetanizing current and records were obtained of the local contraction and of the disturbance which spread orad and caudad. Make and break faradic and galvanic stimuli produced a local contraction but little or no sign of a traveling disturbance. Interrupted galvanic stimulation produced effects similar to those of alternating faradic stimulation. After faradic stimulation a disturbance traveled orad from 1 to 15 cm. and caudad from 1 to 20 cm. The modal distance orad was 5 cm. and the modal distance caudad was 10 cm. The best conduction was seen in the duodenum. In a few animals a disturbance could be detected 40 or 50 cm. caudad to the point stimulated. Such conduction was rapid and was mediated probably by nerves in the mesentery. The response to electric stimulation of the rabbit''s bowel is practically always contraction locally and orad and caudad. Bayliss and Starling''s law does not hold true for the rabbit. Occasionally after traveling a short distance as a wave of contraction the disturbance produced by an electric stimulus manifested itself as a wave of relaxation. In the intact bowel the rate of conduction varied from 1 to 13 cm. a sec. with a mode about 2.5 cm. The mean varied from 5 cm. a sec. in the duodenum to 3.8 cm. a sec. in the terminal ileum. In excised bowel the mean rate varied from 72 cm. a sec. in the duodenum to 6.0 cm. a sec. in the terminal ileum. In both intact and excised gut the rate caudad was a little faster than the rate orad. Conduction in the wall of the bowel appears to take place by way of nerves which are sluggish like those in lowly forms of life.

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