80 Borelli and the Influence [lect. 



This has only to be translated into present language in 

 order to be read as stating that the steady flow from the 

 arteries through the capillaries into the veins is the result of 

 the elastic reactions of the arterial walls, and thus the indirect, 

 not the direct result of the heart -beat. 



Some of Borelli's numerical calculations were misleading, 

 but even in quite recent times numerical calculations of 

 muscular force based on the latest researches have also proved 

 misleading, and such miscalculations in nowise lessen the 

 admiration which one must feel for work shewing, in such 

 early times after Harvey, such a grip of the problems of 

 hemodynamics. We may almost say, even not forgetting 

 Hales, that Borelli brought our knowledge of the subject 

 nearly to the point at which after the lapse of more than a 

 century, indeed of nearly two centuries, Poiseuille and Weber 

 took it up again. 



Borelli completes his treatise on the circulation by con- 

 siderations on the nature and cause of the heart-beat. In its 

 immediate nature the heart-beat, the movement of the heart, is 

 identical with the movement of a limb ; both are muscular 

 contractions of the same order. But the two differ in their 

 ultimate cause. The movement of the limb is the issue of a 

 direct action of -the will, the movement of the heart is not so. 

 "It may arise by organic necessity, the heart may move as 

 " certain automata move. Or possibly the movement may come 

 "from a voluntary effort of which we have ceased to be 

 "conscious because it has been repeated so often and so 

 ° constantly." 



After treating the movements of the circulation thus fully, 

 Borelli goes on to attack by similar methods the problems of 

 respiration. Of his views on this subject I will not speak 

 here ; it will be convenient to deal with them in another 

 connection. Nor did he stop at respiration. As we shall see 

 in the next lecture physiologists were becoming much exercised 

 in their minds concerning the structure of glands and the 

 nature of the process of secretion. Borelli attacked these 

 problems also, and satisfied himself that all the phenomena 

 of secretion could be explained in a mechanical manner by 



