I III MECHANISMS OF IHUI sTION 





peristaltic wave. This first wave is bood followed by othi 

 result that the food ifl forced up into the cecum, againsl the blii 

 of which it is crowded, being meanwhile | from passing into 



the ileum by the operation of the ileocolic Bphincter and l>y the obli 

 manner in which the ileum opens into the cecum. 



As the result of the distention of tl scum Bet up by tl led 



antiperistaltic waves, a true coordinated peristaltic wav< tonally 



initiated, and passes along the ascending colon preceded by the usual 

 wave of inhibition. These waves, however, disappear 1" ach 



the end of the colon, so that the food is again driven back by the 



Fig. !i of time it taki 



of tin- large intestine. 



tailed antiperistaltic waves. The effeel of the movements i^ to ki • 

 and mix the intestinal contents, and thus encourage the absorption 



water from them. The resulting more solid portions then collect toward 



the splenic flexure, ami become separated from the remaining more fluid 

 portion by transverse waves of constriction, which develop into p 

 Btaltic waxes carrying the harder masses into the distal portic the 



colon, where they colled chiefly in the sigmoid flexure. Tl liiig 



colon itself is aever distended with contents and merelj 

 for transferring the masses from the trans toid 



flexure. The time taken for a capsule of hismuth t. 

 parts of the large intestine is shown in Pig !> 



After a certain mass has collected in the sigmoid I im, 



the increasing distention causes an vacua" 



