106 or VITAL MOTION. 



CHAPTER IV. 



C. OF VITAL MOVEMENTS IN THE HEART. 



Preliminary Considerations. 



If we examine the heart, we find many reasons to 

 believe that it is subject to the law which rules the 

 rest of the muscular system. 



The existence of the sigmoid valves at the outlets 

 of the ventricular cavities, is a fact which testifies 

 as to the existence of a power in the heart whose 

 operation is to produce regurgitation of blood : and 

 in those cases, where these valves have been altered 

 by disease, so that the arterial openings are imper- 

 fectly closed, the stethoscope reveals to us the reality 

 of such a regurgitation. Now it is certain, that the 

 force by which the blood is made to rush back in 

 this manner is not owing to the resilience of an 

 elastic tissue seated in the walls of the ventricles. 



