THE DIGESTIVE TRACT 



97 



for the food and a special organ for its digestion. In 

 man, as in the higher animals, the alimentary canal 



Mouth A 



Mouth 



FIG. 59. Diagram to illustrate 

 the gradual development of 

 the alimentary tube as found 

 in the lower and higher forma 

 of animal structure. (Testut.) 



Salivary 

 glands 



Pharynx 



Gullet 



Stomach 

 Pancreas 



.Large 

 intestine 



Appendix- 

 Small- 

 intestine U ^ 



FIG. 60. Diagram of the alimentary tube 

 and its appendages. (Testut.) 



has become a complicated system of organs, each of 

 which has its own peculiar work to do. 



Mouth. The first section of the alimentary canal, 

 the mouth, receives the food. It is provided with grind- 

 ing stones, the teeth; with a device for stirring it up, 

 the tongue ; with muscular walls for keeping it between 

 the teeth and for moving the jaws, the cheeks; and with 

 glands for moistening it with a digestive fluid, the 

 saliva. 



Teeth. The teeth are peculiarly adapted to reduc- 

 ing masses of food into the fine particles required for 



