116 THE DIGESTIVE SYSTEM 



in a salt solution. Keep it in a cold place so that you may continue your 

 investigation the next day. 



XI. Write a paragraph describing the internal organs of the frog, as seen 

 from the ventral view. 



Problem. Study of the food tube or alimentary canal of the 



frog. 



By means of your forceps, lift up the heart and carefully cut it out of the 

 body. Lift up each lung, and carefully cut it out. In a similar manner re- 

 move the liver. 



I. Describe the organ leading into the stomach. This is the gullet or 

 esophagus. Place the blunt end of the dissecting needle in the anterior 

 end of the gullet. Carefully force it through the gullet. Where does it 

 lead ? Is the passageway a continuous one or did the needle meet any ob- 

 structions ? 



II. Make another outline drawing of the frog and sketch in it the alimentary 

 canal. Label gullet, stomach, small intestine, large intestine, and cloaca. 



III. Remove the alimentary canal. The two small brownish red struc- 

 tures near the backbone in the center of the body cavity are the kidneys. The 

 kidneys remove the nitrogenous wastes (urea) from the blood. Each one is 

 connected to the cloaca by a small duct. 



IV. WVite a paragraph describing the alimentary canal. 



Problem. Study of the internal organs of man. 

 Remove the front wall from the mannikin. 



I. Contrast the chest and abdominal cavities of man with the body cavity 

 of the frog. Note the presence of a partition, the diaphragm. 



II. Locate and describe the organs in the chest or thoracic cavity. 



III. Name all the abdominal organs observed in the frog, which can be 

 identified in man. 



IV. State four easily recognized differences in structure or position be- 

 tween the organs of the frog and man. The large intestine takes care of solid 

 wastes only ; therefore, it is a true large intestine and not a cloaca. 



V. Make an outline drawing of the mannikin and sketch the organs in posi- 

 tion. Label chest cavity, diaphragm, abdominal cavity, heart, lungs, liver, 

 stomach, small intestine, and large intestine. 



