PREFACE . 
V 
that are the immediate Infiruments of Motion , 
we dare not attempt to guefs ; thefe being 
wrapp'd up among thofe Secrets only known to 
HIM that order d all "Things : But , as the 
Bodies of Animals are mechanical , and there- 
fore naturally fall within the Sphere of our 
Underflanding , we 7nay make Jome Attejnpts 
towards explaining the jeveral Phenomena that 
belong to it \ and therefore we can only confider 
how its Organs are aSluated , and not what is the 
Caufe of their Motion *, a?id ?nuft take it for 
granted , that the Soul makes her Impulfe on 
the Orgajis , and thejt endeavour to few the 
Nature of the feveral Confeque?ices of that 
Impulfe , as far as it relates to the Motion of 
the Mitfcles . 
IV. 
And this is carried on , as the Reader will 
find , upon a Plan and Foundation not merely con- 
jectural , as is the Cafe of mofi IV r iters on this 
Subject y but ( i.) upon the Knowledge of the Stru- 
cture of a tnufcular Fibre \ ( 2 .) upon a due Con- 
federation 
