APPENDIX TO CHAPTER Xlll. 



three inches further up; to follow it in this part of its course, turn 

 the right lung towards your left and the heart towards your right. 



The vein, just below the diaphragm, may be seen to receive several 

 large vessels, the hepatic veins. 



As it passes through the midriff, two veins from that organ enter it. 



b. Superior vena cava: seek its lower end, entering the pericardium 

 about one inch above the entry of the inferior cava; thence trace it 

 up to the point where it has been cut across; stuff and clean it. 



c. Between the ends of the two venae cavae will be seen the two 

 right pulmonary veins, proceeding from the lung and entering the 

 pericardium; clean and stuff them. 



5. Turn the right lung and the heart back into their natural posi- 

 tions; clear away the loose fat in front of the pericardium, and seek 

 and clean the following vessels in the mass of tissue lying anterior to 

 the heart, and on the ventral side of the windpipe. 



#. The aorta: immediately on leaving the pericardium this vessel 

 gives off a large branch; it then arches back and runs down behind 

 the heart and lungs, giving off several branches on its way. 



b. The pulmonary artery: this will be found imbedded in fat on the 

 dorsal side of the aorta. After a course, outside the pericardium, of 

 about an inch, it ends by dividing into two large branches (right and 

 left pulmonary arteries), which subdivide into smaller vessels as they 

 enter the lungs. 



c. Observe the thickness and firmness of the arterial walls as com- 

 pared with those of the veins; they stand out without being stuffed. 



6. Notice, on the ventral side of the left pulmonary artery, the left 

 pulmonary veins passing from the lung into the pericardium. 



7. Slit open the pericardiac bag, and note its smooth, moist, glis- 

 tening inner surface, and the similar character of the outer surface of 

 the heart. Cut away the pericardium carefully from the entrances 

 of the various vessels which you have already traced to it. As this 

 is done, you will notice that inside the pericardium the pulmonary 

 artery lies on the ventral side of the aorta. 



9. Note the general form of the heart that of a cone with its apex 

 turned towards the diaphragm. Very carefully dissect out the entry 

 of the pulmonary veins into the heart. It will probably seem as if 

 the right pulmonary veins and the inferior cava opened into the same 

 portion of the organ, but it will be found subsequently (13, a) that such 

 is not really the case. Note on the exterior of the organ the follow- 

 ing points: 



a. Its upper flabby auricular portion into which the veins open, 

 and its thicker lower ventricular part. 



b. Running around the top of the ventricles is a band of fat, an 

 offshoot of which runs obliquely down the front of the heart, passing 

 to the right of its apex, and indicating externally the position of the 

 internal partition, or septum, which separates the right ventricle, 

 which does not reach the apex of the heart, from the left, which 

 does. 



10. Dissect away very carefully the collection^ of fat around the 

 origins of the great arterial trunks and that around the base of the 

 ventricles. 



