DIGESTION, CIRCULATION, AND ABSORPTION 269 



2. Study a piece of tripe. What is tripe ? What advan- 

 tage in the " honeycomb " arrangement ? 



3. Why does a man need teeth ? Are they all of the same 

 shape ? 



4. (Home work.} With the aid 

 of a small mirror count the teeth of 

 each jaw. Answer the following 

 questions: 



a. The total number on each 

 jaw ? 



b. The number of broad teeth 

 (incisors) in the front of each jaw? 



c. The .number with one point on 

 the biting edge (canines) ? 



d. The number with two points 

 on the biting edge (premolars or 

 bicuspids) ? 



e. The number with more than 

 two biting points (molars) ? 



f. Compare your results with 

 Figure 61. How do they agree ? 

 Differ ? 



g. Examine the teeth of a cat or 



a dog. What difference do you find FIG. 60. Front view of the or- 



as to the kind and number of teeth ? 

 What kind of food do they eat ? 



Conclusions. 1. Is there any 

 connection between the food and 

 the kind of teeth found in any 

 animal ? 



2. What is the use of the teeth ? 



3. Why is thorough chewing a 



gans of digestion of man. a, 

 c, e, colon ; d, duct of the gall 

 bladder ; dm, diaphragm ; g, 

 gall bladder ; h, hepatic duct 

 from the liver ; k, kidney ; I, i, 

 small intestine ; Iv, liver : n, 

 opening of the bile duct into 

 the small intestine ; oe, esoph- 

 agus ; pn, pancreas ; r, rectum ; 

 st, stomach ; ftp, spleen ; vx, 

 vermiform appendix. 



necessary first step in digestion ? 



4. Through what organs does the food pass in the course of 

 its passage through the body of man ? 



