THE MECHANISM OF THE HEAKT PUMP 917 



It is evident that an unrestricted diastolic filling of the heart is not of 

 unqualified advantage to this organ. If during diastole the heart be too 

 forcibly distended, as may easily occur after opening the pericardium, or 

 in cases of enfeeblement of the heart's action by chloroform poisoning or 

 otherwise, the muscle fibres of the heart may be quite unable to contract 

 against the distending force represented by a pressure in the heart equal 

 to that in the aorta. Under such conditions we may have sudden heart 

 failure, which can only be relieved by diminishing the diastolic distension, 

 as, e.g., by letting blood from the veins opening into the heart. 



