C 3 ] 
be appointed hereafter to undertake the fame Task* 
by bringing the feveral Opinions together in a fmali 
Compafs before him, 
IV. 
Mod: Authors agree, That a Fluid, commoply 
call’d Animal Spirits , flows from the Brain , by the 
Nerves to the Mafcles , in order to move them ; but 
are at a Lofs to know how it is performed ; and 
aifo, by what means thofe Spirits are fent, fo fwiftly, 
into this or that Mufcle to be moved, 
V. 
Some endeavoured to explain it, by fuppofing cer- 
tain Valves placed in the Cavities of the Nerves, 
(where they are divided into Branches *, to go to 
different Mufcles) in order to flop the Reflux of the 
Spirits, and caufe them, upon being brought back 
from one Mufcle, to be determin’d to the other, from 
the Valve. 
VI. 
Others, not well fatisfy’d with this Scheme, ima- 
gined a double Tube, palling from one Mufcle to the 
other, fo plaeed, as that the Orifice of one, in its 
Contra&ion, (being furnifhed with a particular Valve) 
might be opened, and the Spirits immediately flow 
through it, from the Mufcle to be relaxed into that 
B 2 to 
* Cartef. lib. de Homine , and feveral of his Followers, were for 
, placing Valves oqly in the Divifions of Nerves ; whereas Regius^ 
Philo foph. Nat. lib. 4. cap 16. thought them to exift elfe where in 
the Nerves. 
