CHAPTER X. 

 DIGESTION. 



1. Introductory. We learned almost at the outset of 

 our anatomical study, that the alimentary canal is but 

 a tube (Fig. i) which, beginning at the mouth, runs 

 through the neck, chest, and abdomen; and ends by 

 opening again on the outside at the lower part of the 

 trunk of the body. We now have further to observe 

 that it is wide in some parts, like the stomach and large 

 intestine (all to be presently described), and narrow in 

 others, like the gullet and small intestine, which will 

 also be presently described; some parts of it are straight 

 and others coiled; but it has no branches which reach 

 out into the arms or legs or brain. Nevertheless, after 

 a good dinner we feel no doubt that what we have eaten 

 is going to strengthen our limbs and every other part of 

 the body. To accomplish this, the nourishing portions 

 of the food must get through the walls of the alimen- 

 tary canal, and then be carried to all the organs. 



2. Digestion The first important thing that happens 

 to our food inside the alimentary canal, by way of pre- 

 paring it to reach distant organs, is that its solid parts, 

 or at least those of them which are nourishing, are dis- 



1. How do the various parts of the alimentary canal differ ? What 

 must happen in order that food may nourish all parts of the body ? 



2. What is the first important work inside the alimentary canal to 



