VIII. 



THE CIRCULATION OF THE BLOOD. 

 A. The Heart and Related Organs. 



Material. Obtain from the market the "pluck" of a sheep, pig, 

 or calf. This includes the heart, lungs, trachea, and diaphragm. 

 Care should be taken to engage it beforehand, with the request that 

 it be left intact, or the heart will be punctured and there will be no 

 pericardium. 



Study the entire specimen. 



Identify : 



a. The lungs. 



b. The trachea, or windpipe leading to the lungs. 



c. The oesophagus, a thin-walled tube near the trachea, 

 is sometimes cut away. 



d. The heart. 



e. The pericardium is the thin- walled bag in which the 

 heart is held. Does it fit closely to the heart ? Puncture 

 the pericardium, if it has not already been cut. 



/. The pericardial liquid is within the pericardium. 



g. The diaphragm is the muscular membrane just under 

 the heart. What is its shape and texture? Part of it 

 may be cut away. 



h. Sketch all the parts to show the relation of one to 

 another. 



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