[ 11 7 ] 
CHAP. IX. 
The Circulation of the Blood, 
I N order to view the Blood circulating 
through its VeJJ'els , we muft make ufe of 
fuch /mail Creatures as by their Tranfpa- 
rency permit us to look within them, and 
fee what pafles there : for, in a Man, or any 
of the large Animals, the Skin is fo opake 
that we cannot difcern even the fine Blood- 
Yefiels themfelves, and much lefs the Cur¬ 
rent that runs along them. Our Informa¬ 
tion, however, will not be greatly different $ 
for the whole Animal Creation is efiablifhed 
on one and the fame Plan, and the Circu¬ 
lations in the meaneft living Creature are 
carried on through Yefiels of a like Structure 
(in the general), and are accelerated or re¬ 
tarded by the fame Caufes, as in the nobleff. 
And, in Truth, as to the Circulations of 
the Fluids, and the Motions of the Bowels* 
the Brain, or any of the internal Parts, 
more Knowledge may be gained by infpect- 
ing InfeBs and fmall Animals with the Mi- 
crofcope } than by the mofl fkilful and curious 
Difie&ions, or anatomical Experiments on 
larger Subje&s. For the Skins of fome of 
thefe little Creatures are fo tranfparent, that 
we may fee plainly through them the Order 
and Difpofition of the Yefiels underneath * 
and 
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