OF THE ALIMENTARY CANAL 101 



stomach is empty. Even then peristalsis may not 

 cease (Hertz), but the pylorus Hes open, and bile and 

 duodenal contents pass in and out without causing 

 any discomfort. 



The effect of the principal food-stuffs on these 

 movements must now be noticed. Water runs out 

 at the pylorus almost as quickly as it enters by the 

 cardiac orifice. The clotting of milk is probably 

 designed to prevent the same thing happening, 

 otherwise it would run through the stomach and 

 duodenum without giving the pepsin and trypsin 

 time to act upon it. Carbohydrates do not stay 

 long in the stomach ; fats and proteins, however, 

 may remain for several hours. In a normal human 

 stomach, nothing should be present before breakfast 

 in the morning ; if there is, some stasis must be 

 occurring. 



Emotion hinders peristalsis. Excitable cats, 

 especially males, often show no movements for a 

 long time after being tied down ; Cannon did most 

 of his work with placid elderly female cats. Fever, 

 such as distemper in dogs, also diminishes the move- 

 ments ; in fact food may he all day without moving. 

 There is great delay after abdominal operations. If 

 the jejunum is cut across near the upper end and 

 then sutured, the pylorus remains tightly closed for 

 about six hours, even if food is given. 



Solid pellets, such as bismuth pills or lead shot, are 

 not allowed to escape readily, and a bread mixture, 

 which usually began to pass out into the duodenum 

 in fifteen minutes, was retained for forty minutes 

 when the pills were given with it. This probably 



