C 60 ] 
Syjloles and © iaftoles analogous to the Heart and 
its Auricles, 1 think we have good Reafon to con- 
clude, that the fame Principles which contrail and 
dilate the voluntary Mufcles, in the above-mention’d 
Condition, are the Principles which occafion the 
Syfiole and Diajiole of the Heart, with this Dif- 
ference only, that the Influx of the Blood into the 
Sinufes of the Heart, is what no other Mufcle in 
the Body has or receives; and without Doubt this 
may truly be reckon'd the greateft Affiftant in di- 
lating the Ventricles of the Heart, after the attraft- 
ive Influence of the nervous e_jEther ceafes, and 
the c /Equilibrium is reftored between the ftretched- 
out Fibres and thofe which were contracted. 
CXXXVIII. 
What has been faid feems greatly to evince the 
Truth of our third and lafl Suppofition; viz. that 
the Diaftole of the Heart may depend on an Abate- 
ment of Tenfion in the contracted Fibres, a Vis Re- 
Jiitutionis in fuch as are over-ftretched, and the In- 
flux of the Blood conjunctly. 
CXXXIX. 
Give me Leave to relate two or three Experi- 
ments which I have made, in order to illuftrate the 
foregoing Theory, and then I fhall conclude. 
CLX. 
