THE PIGEON 183 



the heart as you can. Draw the cords tightly, and after a 

 secure knot is made, cut off the blood vessels between the 

 cords and remove the heart. Preserve the heart in alcohol 

 for further study. 



(6) Remove the lungs and dissect them further. Follow 

 the bronchial tubes out in their subdivisions as far as pos- 

 sible. Do you see tubes other than bronchial tubes in 

 the lungs? What are they? (Blood vessels). How can 

 you tell them from bronchial tubes ? Remove a small piece 

 of the lung and place it under the lov/ power of the micro- 

 scope. From its appearance and from what you have found 

 out, of what do you think the lung is composed? 



(7) Study the alimentary canal. Trace the esophagus 

 down to the slightly dilated stomach. Observe the tube 

 closely to find traces of muscular bands or coats. Do you 

 find any such structure at the end where it has been cut off? 



Below the stomach is the gizzard, the large rigid body 

 lying in the folds of the alimentary canal. Turn it to one 

 side. Where does the alimentary canal enter? Where does 

 it leave the gizzard ? Is the gizzard caecalf 



(8) The part of the alimentary canal lying just back 

 of the gizzard is the duodenum. In a fold of the duodenum 

 is the pancreas. What work is performed by the pancreas ? 

 Where are the ducts leading into the intestine? The liver 

 has already been noticed perhaps. What part of the body 

 cavity does it occupy? Turn the lobes aside and find the 

 gall sac. What does it contain? Of what use is it? How 

 does this liquid get into the alimentary canal? Find two 

 ducts leading from the liver to the duodenum. Note the 

 folds in the intestine below the duodenum. How are they 

 held in that position? What is the nature of this mem- 



