ELEMENTARY PHYSIOLOGY. XV. 



9. Holding the heart vertically, pour water into the 

 pulmonary artery; observe from below the form of the 

 semilunar valves, and their mode of closing. 



10. To observe the valves from above, insert into the 

 pulmonary artery a short wide tube, fill it with water, 

 and cover it with a piece of glass, excluding air-bubbles. 



11. Prolong the incision of 8 so as to lay open the 

 pulmonary artery. Note 



The form and attachment of the semilunar valves. 



The small nodule of tissue in the middle of the free 

 edge of each valve, the corpus Arantii. 



The slight depressions in the arterial walls opposite 

 each valve, the sinuses of Valsalva. 



12. Lay open the left auricle in a manner similar to 

 that employed for the right. Note that the left auriculo- 

 ventricular valve, the bicuspid or mitral, has but two 

 flaps. Observe its manner of closing (cp. 7). 



13. Lay open the left ventricle in a manner similar to 

 that employed on the right side, carrying the incision at 

 first along the extreme left of the heart. Note the thick 

 walls, the mitral valve, &c. 



14. Lay open the aorta, and examine its semilunar 

 valves, corpora Arantii, and the sinuses of Valsalva, 

 which are here very distinct. Note that the coronary 

 arteries open respectively into two of the sinuses. 



DEMONSTRATIONS. 



1 . The beat of the isolated mammalian heart and the 

 effect of adrenaline upon it. 



2. The stethoscope and the sounds of the heart. 



3. The cardiograph. 



