[ 5i 3 
Mate i and confequently whenever the Nerves are 
imprefs’d by the Soul, there is an immediate Infla- 
tion of all the Cells, in the Fibres of that Muldc 
which is to perform a voluntary Motion. 
XI. 
And thefe mufcular Cells, together with the ner- 
vous Tube that opens into each mufcular Fibre, are 
conftantly full of this inflating Matter to a certain 
Degree j that is, fill’d to a Medium between their 
utmoft Comprefiion or Emptinefs, and their utmoft 
Capacity of Repletion. By this means, the mufcular 
Fibres, when at Reft, are in a Medium between Dif- 
tenfion and Contra&ion ; but are diftenftble to near 
a Third longer, and contra&ible to near a Third 
fhorter, than when in a State of Reft ; the former, 
by the RetraBion of Part of the inflating Matter 
back into the Nerves 5 and the latter, by its Imjml- 
flon or Inflation into the Cells from the Nerves. 
xir. 
There is no NecelTity for imagining, with fome 
Authors, that the Soul makes her Impulfc in the Head 
rather than any other Part, in order to impel from 
thence the inflating Matter of the Nerves to this or 
that Mufcle : Becaufe, by fuppofing the Nerves al- 
ways thus full, the fmallcft Impulfe on the Part of a 
Nerve leading to this or that Mufcle will be fufficient 
to perform what is neceflary ; whereas, if we confine 
the Power of the Will to the Brain, may there not 
be Danger of Irregularities like Explofions, from 
thence into the different Divifions of a Nerve, and 
Hz fo 
