76 Borelli and the Influence [lect. 



He fully accepts Harvey's views, and developes them in his 

 own way. Although Harvey could not be ignorant of the 

 exact mathematical and physical knowledge which was being 

 gathered up in his time, he as we have seen makes little or no 

 use of it in his great work. That was based exclusively on the 

 teachings of anatomy and the results of experiments on living 

 animals ; he never made use of the new mathematical or even 

 the new physical methods. This is exactly what Borelli does. 

 To the physicist the problems of the circulation have always 

 been fascinating ; they obviously were so to Borelli, and he 

 developes a number of mechanical investigations and specula- 

 tions. While his brother mathematician Descartes was content 

 with the old view of the expansion of the ventricles by the 

 rarefaction and dilatation of the contents through the innate 

 heat, Borelli seizes the Harveian view of the propulsive power 

 of the heart in its systole and likens the ventricle to a wine- 

 press or to a piston. He dwells on the mechanical action of 

 the spiral arrangement of the fibres of the ventricle, an 

 arrangement which he says he himself had discovered, though 

 there is reason to think that the observation is due to Malpighi, 

 and speaks of the work done by the heart in the following 

 terms : 



" The true action of the muscle of the heart is the contrac- 

 tion of its ventricles, and the compression and expression of 

 " the blood contained in them is carried out after the manner 

 " of a winepress, and that not by the contortion of the spiral 

 " fibres of the heart but by their inflation and tension." 



He gives the following as the reason why the lateral walls 

 of the heart are brought together in the systole : 



" All the almost innumerable fibres are carried obliquely 

 " and transversely round the sides of the heart, and form a 

 "number of strata placed one upon the other like a series of 

 "membranes. When therefore the fibres of any stratum are 

 " inflated, these touching each other laterally and lying in one 

 "plane, naturally push each other sideways, and so mutually 

 " shove each other out of their proper places, and push each 

 "other away from their proper situation, namely towards the 

 " base and the apex. This would tend to increase the interval 



