INNERVATION OF THE DIGESTIVE TUBE 191 



gastric folds and plicae and the intestinal villi where many of 

 them terminate on cells of the digestive epithelium. The fibers 

 which terminate on cells of the digestive epithelium are, doubtless, 

 the dendrites of 'receptive' or sensory neurones. 



3. The orientation of the neurones in the ganglia of the myen- 

 teric and the submucous plexuses and the distribution of their 

 axones and dendrites strongly suggest that the sympathetic sys- 

 tem, like the other functional di\'isions of the nervous system, is 

 essentially a system of reflex arcs involving both sensory and 

 motor neurones, some of which are strictly local while others are 

 less local or even involve centers in the cerebro-spinal nervous 

 system. 



4. The normal nervous control of the digestive functions is 

 probably exercised primarily by the local sympathetic mechan- 

 ism, the general control which is exercised by extrinsic nerves 

 being largely tonic in character. The major portion of such tonic 

 control is probably exercised by the vagi. 



BIBLIOGRAPHY 



AuER, John 1910 The effect of severing the vagi or the splanchnics or both 

 upon gastric motility in rabbits. Amer. Jour. Physiol., vol. 25, pp. 

 334-344. 



Bayliss, W. M. and Starling, E. H. 1899 The movements and innervation 

 of the small intestine. Jour. Physiol., vol. 24, pp. 99-143. 



Cajal, S. R. y. 1905 Tipos celulares de los ganglios sensitivos del hombre y 

 mamiferos. Trabajos de Lab. de Invest. Biolog. de la Univers. de 

 .Madrid, T. 4. 



Cannon, W. B. 1906 The motor activities of the stomach and small intestine 

 after splanchnic and vagus section. Amer. Jour. Physiol., vol. 17, 

 pp. 429-442. 



1912 Peristalsis, segmentation, and the myenteric reflex. Amer. Jour. 

 Physiol, vol. 30, pp. 114-128. 



DoGiEL, A. S. 1895 Zur Frage tiber die Ganglien der Darmgeflechte dei den 

 Siiugetieren. Anat. Anz., vol. 10. pp. 517-528. 



1896 Zwei Arten sympathischer Nervenzellen. Anat. Anz., vol. 11, 

 pp. 679-687. 



HuBER, G. C. 1897 Lectures on the sympathetic nervous system. Jour. Comp. 

 Neur., vol. 7, pp. 73-145. 



