S2& 



Mr. Alderson on the 



It consists of a vertical cylinder, supported by a spindle, allowing 

 of a rotatory motion. This cylinder is met by another, which is 

 horizontal, and in which, near its extremities, and on opposite sides, 

 are cut two orifices, from these orifices the fluid supplied from a 

 spout is suffered to escape. The effect produced, is a rotatory 

 motion, arising not from the resistance given to the issuing fluid by 

 the air (for it would have place in vacuo), but from the v/ant of re- 

 sistance to counteract the pressure of the fluid against the sides of 

 the horizontal cylinder opposite the orifices, and this is the principle 

 I purpose making use of to account for the motion of the heart. 



of the isochronism of the beat witli the contraction of the ventricles, though 

 he has no where accounted for it. " Au moment ou I'art^re vient frapper le 

 doigt, I'oreille est K'gerement soulev^e par un mouvement du cceur isochrone 

 a celui de I'artere et accompagn^ d'un bruit un peu sourJ quoique distinct. 

 L'isochronisme ne permet pas de m^connaitre que le phenom^ne est du ^ la 

 contraction des ventricules." — De I' Auscultation Mediate, vol. ii. p. 21 6. 



