370 



PRINCIPLES OF GENERAL PHYSIOLOGY 



A fact which indicates the dependence on the central nervous system of those co-ordinated 

 movements of the intestines which are not included in the myenteric reflex is described l>y 

 Gottfried Boehm (1912). Cannon had shown that the food, after passing into the colon, is 

 kept there for a time and churned backwards and forwards in order to ensure absorption ot 





FIG. 98. PORTRAIT AND SIGNATURE OF IVAN PKTROVICH PAVLOV. 



water and any products of digestion still left. Boehm found that excitation of the vairus 

 nerve increased the vigour of the backward movements. 



THE SECRETION OF THE DIGESTIVE JUICES 



The food, as it passes along the alimentary canal, is subjected to the action of 

 a series of fluids containing enzymes, whose action will be described in the 

 following section of this chapter. 



