iv DIGESTION IN THE INTESTINE 249 



the intestine, which show that stimulation of the splanchnics in 

 some animals increases, in others inhibits muscular tonus ; in 

 others again there is inhibition with preliminary augmentation 

 of tone. Bunch concludes that the splanchnics contain fibres of 

 opposite functions, and that excitation of the nerves produces one 

 or the other effect, according as the inhibitory or the motor fibres 

 preponderate in the particular animal. 



Ehrmann (1885), in work carried out in von Basch's laboratory, 

 suggested crossed innervation by the two kinds of fibres contained 

 in the splanchnics, and assumed that they were motor for the 

 longitudinal and inhibitory for the circular coat. 



On the other hand, Courtade and Guyon (1897), in experiments 

 undertaken in FranQois-Franck's laboratory, state that in normal 



FIG. 84. Intestinal contractions. Balloon method. Intestine returned to abdomen. Shows 

 inhibitory effect of exciting peripheral ei 

 white mark shows duration of excitation. 



inhibitory effect of exciting peripheral end of cut splanchnics. (Bayliss and Starling.) The 

 of excitat" 



conditions of the intestine, excitation of the splanchnic produced 

 exactly the opposite effects, viz. contraction of the circular and 

 inhibition of the longitudinal coat. But they obtained the same 

 results as Ehrmann when the gut was in an abnormal state owing 

 to defective circulation and diminished tone of its walls. The 

 splanchnics must therefore contain motor and inhibitory fibres 

 for both layers of muscle. 



Whatever interpretation be given to these conflicting results, it 

 is certain that under really physiological conditions the intestine, 

 on opening the abdomen of a dog in a warm saline bath, with intact 

 splanchnics, is absolutely motionless. Under these conditions 

 Bayliss and Starling (1899) find that division of the splanchnics 

 produces no immediate change in the intestines; but after 

 15 to 30 minutes they gradually become more active, the previously 

 motionless intestine begins to beat rhythmically, and any con- 

 tractions which were previously present become stronger and more 

 regular. The vessels become hyperaernic from vascular dilatation 



