104 



ELEMENTARY PHYSIOLOGY 



the nature of the food taken ; but it is generally a thick, milky, 

 acid fluid, possessing a disagreeable odour. 



The changing of the food into chyme by the gastric fluid is 

 called chymification. The average time occupied in producing 

 this change is from three to four hours. 



The information we possess concerning these changes in the stomach is 

 the result of a number of observations made on living and on recently- killed 

 animals ; and not a little is due to the investigations of Dr. Beaumont, who 

 had an opportunity of witnessing the action of the gastric fluid in a Canadian 

 whose stomach had been perforated by a bullet. Dr. Beaumont introduced 

 various substances into his stomach, and noted the time required to chymify 

 various foods. A few of the results obtained are as follows : 



Time occupied in Chymification. 



Hours 

 . I 



: it 



Boiled rice 

 Boiled tripe 

 Raw apples- 

 Boiled salmon . 



Boiled sago . . . if 



Boiled, cured cod-fish . . 2 



Boiled beans . . . 2 -> 



Sponge cake . . . 2 1 



Baked potatoes . . . 2\ 



Roasted goose . . . .2^ 



Boiled gelatine . . . .2.1 



Broiled lamb . - . 2 a 



Boiled beef . . . . 2| 



Boiled apple dumplings . . 3 



Hours 



Roasted beef . . .3 

 Boiled mutton ... .3 

 Boiled carrots . . . 3? 

 Roasted mutton . . Si- 

 Bread . . . . .34 

 Boiled potatoes . . 3 

 Boiled turnips . . . 3$ 

 Cheese ..... 3| 

 Boiled eggs (hard) . . s| 

 Fried eggs 3t 

 Boiled cabbage. . . -4 

 Boiled or roasted fowl . . 4 

 Roasted pork . . . Sk 

 Boiled gristle . . . 5% 



Some albuminous substances, such as casein (of milk), are 

 coagulated or curdled by the gastric fluid, thus becoming solid 

 before being digested. 



The soluble and diffusible substances formed by the action of 

 the gastric fluid on albuminous foods are called peptones. These 

 peptones are at once fit for absorption, and are to a certain ex- 

 tent taken up by the mucous membrane of the stomach, and pass 

 into the blood circulation. 



(ESOPHAGUS 



SUMMARY. 



/ Narrowest portion of alimentary canal. 

 I Length about 9 inches. 



Communicates between pharynx and stomach. Pass- 

 \ ing through the diaphragm. 



(i. Outer muscular longitudinal fibres. 

 1 n nat . I Circular fibres. 



2. Middle areolar (filamentous). 

 1 3. Inner mucous. 



