VARIATIONS IN OUTPUT 



69 



increased by distension. The next systole is stronger, and 

 results in, say, 6 c.c. being expelled, 6 c.c. remaining in the 

 ventricle. At the next diastole, the distension is greater 



Fig. 16. — Effect of alterations in venous supply on the heart. The 

 curved line on the left shows the ventricular capacity in c.c. (From 

 Starling's Princi'ples of Physiology.) 



still, 6 c.c. -f 8 c.c. = 14 c.c, and is followed by a still 

 stronger systole, which probably succeeds in expelhng 

 8 c.c, leaving 6 c.c. in the ventricle. The normal output 

 is thus restored ; the only difference lying in the diastolic 



