[ *5 ] 
of the fkfhy Fibres caufes the Tendons to come nearer 
t-o each other, which every-body has laid; but the 
grand Queftion is. How they are contra&ed ? And 
as to this particular Structure of the Fibres, I believe 
none but the Author himfelf ever fanfied he faw 
them fo. For, fuppofing this angular Form in every 
one 
to be the real Structure, the 
Contraction would reduce it to this Form" 
But the Caufe and Manner how this is brought about 
upon this Plan is inexplicable jefpecially lincc much 
Force is required to draw the Weight or move- 
able Parr. But enough of this Author : Let us now 
proceed ro give a fhort Sketch of the Opinion of a 
much more famous Author, the great Dr. IVillis. 
XX. 
He commends the foregoing Author very . w . u 
much for his ingenious Conjecture about the 
Structure of the Mufcular Fibres ; and gives a Detail of 
what that Author has laid concerning them, with an 
Air of Approbation ; but attempts’ accounting for the 
Caufe and Manner of the Performance of Mufcular 
Motion, of which the following is the Sum : 
XXL 
Animal Spirits are carried from the Encephalon* 
- by the Nerves, to every Mufcle ; and are received 
by the membranous FibnlUe* and by thefe forwarded 
into the tendinous Fibres; there to be referv’d as in a 
proper Receptacle or Store- houfe. Thefe Spirits, as 
they are of a raoft active and elaftic Nature, as often 
2 as 
