46 



STOMACH. 



food into the gullet. The circular fibres of this organ,, 

 stimulated by its presence, contract upon it and thrust 

 it onward. The next set of fibres, then act and propel 

 the food still farther, until by means of this successive 

 contraction of the circular fibres, it at last reaches the 

 stomach. Deglutition seems at first thought to be per- 

 fectly under our control, yet nearly all its acts are en- 

 tirely beyond it, and are purely instinctive. The food 

 must be of just such size and quality, and properly masti- 

 cated, before it can be swallowed, endeavor as much as 

 you will to get it down. Try to swallow your saliva five or 

 six times in quick succession, and you will see how im- 

 possible it is to perform deglutition by the will, unassisted 

 by any instinctive wants. You know how difficult some 

 people find it to swallow a pill. 



Emily. I believe I can testify to the truth of that 

 fact myself, and, I am confident, you would be the last 

 person to refuse my testimony. 



Dr. B. The rest of the digestive operations take 

 place in the abdomen, the largest cavity in the body, and 

 containing, besides the stomach, many other important 

 organs. This cavity is irregularly egg-shaped, and 

 bounded on the upper side by 

 the diaphram or midriff, a 

 thin membranous muscle, dis- 

 posed in the iorm of an arch 

 over the top of the cavity, and 

 separating it from the chest. 

 Posteriorly the abdomen is 

 bounded by . the back-bone, 

 and anteriorly and laterally by 

 the abdominal muscles, the ac- 

 tion of which is likewise con- 

 siderably connected with that 

 of the organs within. In the 

 upper portion of this cavity, on 

 the left side, is situated the 

 stomach, a figure of which you may see in this engrav- 

 ing. It is likened by some to a Scottish bag-pipe in 



1. Cardiac portion of the stomach. 



2. Pyloric portion of the itomaeh. 

 3. 



4. 



canal 



