[ *0 1 
% 
every Incifion made acrofs them, when the two 
Segments of the Mufcle fo divided, retire, one to its 
Infertion, and the other to its Origination 5 that is, 
every Fibre is always ftretched out beyond its natu- 
ral State of Reft or Quiefcence, fo that both Ends 
of it retraCt a confiderable Diftance after being cut 
afunder. Now there are two Things which feem to 
be principally concerned in this Affair 5 viz. the 
Impulfe and Frefliire of the circulating Fluids, always 
diftrafting the Fibres, and a c^nftant Nifus or En- 
deavour in the conftituent Particles of the Fibres to 
run clofer together, when fo diftended, by means 
of their mutual Attraction towards each other. 
XXIII. 
The Equilibration which is ever preferved between 
the antagonift Mufcles, in a healthy State, unlefs 
when the Will direfts it otherwife, arifes from this 
Vis Reftitutionis $ which being ftronger oj: weaker ac- 
cording to the Degrees of Tenfton, and the Degrees 
of Tenfton depending upon the Velocity and Quan- 
tity of Fluids circulating through every Fibre 5 it 
follows, that as long as the Fluids have the fame free 
Accefs to every voluntary Mufcle, fo long, will the 
<^sEqiiilibrium be maintained. 
XXIV. 
In an Effay which I publifh’d on this Subject of 
mufcular Motion, in the Year 1733, 1 endeavoured 
to prove that every the lead Corpufcle of Matter is 
endued with an attractive Virtue on one of its Sides,, 
and 
