[ 4 +] 
LECTURE III. 
xcw 
Xead April Confirmation of the Truth of what 
5747,1 A ^ as faid. * n t ^ ie £wo preceding 
Lectures, and for a further Illuftration of this Sub- 
ject of mufcular Motion, I beg Leave to offer fome 
Thoughts concerning the Caufe and Manner of 
Action in the involuntary Mufcles; and after that 
I {hall relate fome Experiments, which I have made 
in order to illuftrate our Theory in general, as far as 
the Nature of the Subjeft will admit* 
XCV! 
When any Mufcle, voluntary or involuntary, is* 
fully contracted, that is, when its component Par- 
ticles are drawn into the clofeft Contacts they are 
capable of, by the Influence of the ^ethereal Medium 
in the Nerves, it is evident, from all the Laws of 
Matter, that they would not recede from each other, 
again without fome impreffed Force. Now in all 
the voluntary Mufcles we very well know, that when 
one Set of them are contracted, their Antagonifts 
are lengthen'd, and vice verfa . ; fo that the Vis Re - 
Jt it idioms in all the ftretched-out Fibres, and the 
Momentum 
/ 
