ON THE MOTIONS AND SOUNDS OF THE HEART. HGI 



mur was accompanied by a thrilling motion, sensible to the 

 finger of the operator, and synchronous with the impulse. A 

 lamina of each sigmoid valve was then hooked up (with dissect- 

 ing hooks), when a sound was heard not followed by a second 

 sound, but on removing the hooks the second sound was again 

 heard. 



On inverting the auricles again the chordae tendineae of the 

 mitral valve alone were felt to become tense in systole and lax 

 in diastole. A finger being introduced into the left ventricle 

 through the auricle, the first sound was heai'd with a murmur. 



Experiment 13. — Subject, a young ass, pithed. On opening 

 the chest, and then the pericardium, both sounds were distinctly 

 heard, but feeble. On touching the arteries in the vicinity of 

 the valves, a sensation of flapping (or jerking) observed by all, 

 commencing immediately after the systole, and accompanying 

 the second sound. 



The awls being introduced into the arteries (so as to hook up 

 the valves), the second sound was wanting. After removing the 

 awls, at first but the systolic sound was heard, but after a short 

 time both were heard by all. 



On opening the heart (at the close of the experiment), the 

 valves were found to have been sufficiently hooked up in both 

 arteries. 



Experiment 14. — Subject, a young ass, pithed. After open- 

 ing the chest the pericardium was opened, and a thick layer of 

 tow was interposed between the heart and surrounding parts, 

 the heart continuing to act. At first the systolic sound was 

 heard, followed by a bellows murmur ; but afterwards the flap- 

 ping sensation and second sound very distinct also. 



The finger being introduced into the left ventricle by inver- 

 sion of the auricle, was felt to be gently embraced and pushed, 

 as if by a membrane distended with blood. On the right side 

 nothing similar uneqviivocally observed. On pressing the aorta 

 or pulmonary artery between the finger and thumb gently, a 

 *'to and fro" thi'illwas felt accompanying the systole and dia- 

 stole of the ventricles, and terminated by a flap. The sensation 

 of flapping (or jerking) was felt to be synchronous in the two 

 arteries. 



The tension and hardness of the ventricles during their systole 

 was very remarkable. 



The pulmonary artery being cut across, the first sound was 

 still loud, and the aorta being then cut across (likewise), the same 

 result was obtained (viz. a first, without a second sound). The 

 heart was then severed from its other attachments, and the (first) 

 sound was still heard distinctly. 



