MOUTH. '0< 



t. Why surely Dr. B., you cannot be serious ; 

 I never m my life beheld a stomach, nor any part of one. 



Dr. B. Perhaps not a human stomach. But tripe, 

 an article of food, which no doubt you have seen and 

 eaten in the course of your life, is the stomach of the 

 ox, which, in the same way as man's, has these three 

 coats which I have described. After it has been fried 

 you can easily separate them and see their relative con- 

 nexions. 



Emily. I recollect now distinctly the soft and deli- 

 oate appearance of the mucous coat and directly under 

 it, the muscular coat with its red and parallel fibres very 

 perceptible. 



Dr. B. As different parts in the process of diges- 

 tion are performed in different parts of the digestive 

 system of organs, it will be convenient for us to describe 

 them both in connexion, proceeding in the order in which 

 they present themselves. 



Emily. And first I suppose, we have the mouth with 

 its appendages. Pray do be particular in describing the 

 teeth, for you know, I have particular cause to be inter- 

 ested in their organs. 



Dr. B. Well then let us look at the mouth in the 

 first place. In shape, it approaches the oval nearer than 

 any other figure. Above it is bounded by an arch form- 

 ed by a bone called the palate ; below by the tongue ; 

 behind chiefly by the veil of the palate and \hepharynx ; 

 anteriorly by the lips, and laterally by the cheeks. This 

 cavity may be greatly enlarged, you know, by separa- 

 ting the jaws, and the cheeks, and depressing the 

 tongue. The upper jaw constitutes a portion of the 

 face and therefore moves only with the head ; the lower 

 jaw on the contrary, is fixed by joints to the head, and 

 is capable of considerable extent of motion moving 

 freely upwards and downwards, and a little from side to 

 side. To understand the admirable though simple con- 

 tftYance by which this lateral motion is effected, cast 

 4 



