44 HUMAN PHYSIOLOGY 



ingly, the interior of the stomach may literally be 

 said to blush on the entrance of food. The gastric 

 juice is poured out upon the food, and the stomach's 

 movements, of which in health we are unconscious, 

 serve thoroughly to mix the food with the secretion 

 of the organ. It would appear that the food is made 

 to circulate within the stomach in a somewhat figure- 

 of-8 fashion, and this again would appear to proceed 

 during the whole period that the food remains in 

 the stomach. The hinder aperture of the stomach, 

 or that which leads into the intestine, is known as 

 the pylorus (Fig. 10), the aperture by which food 

 enters the stomach being termed the cardia, as we 

 have already noted. The pylorus is kept closed by a 

 valve-like muscular arrangement which exists in 

 that situation, and it is only when the proper time 

 arrives for the food to pass out into the intestine 

 that is, when digestion in the stomach has been 

 completed that this muscular ring uncloses, and the 

 subsequent contraction of the stomach forces the 

 digested material into the bowel. 



WHAT THE STOMACH DIGESTS. Allusion has 

 already been made to the work of the stomach, in 

 respect that the amount of its labours is inferior to 

 that discharged by, say the bowel or intestine. 

 Hence we now arrive at the interesting fact that 

 there is only one class of foods upon which the 

 stomach can exert any decided action. These foods 

 are the nitrogenous ones, represented, as we have 

 seen, by albumen, casein, legumin, gluten, and the 

 like. They represent of course the typical body- 

 building elements. As by far the larger proportion 

 of our daily meals consists of non-nitrogenous 

 starch, sugar, and fat, it therefore follows that the 

 stomach's share in the work of digestion is relatively 



