f 1004 ) 
Elaftick Fluid, will appear from the following Experi- 
ment. 
Exp.W. In a fmall quantity of Serum o{ Human 
Blood, I dillblv’d fo much Blood, as that the Globules 
might not lye too thick together, to hinder their being 
feen diftin(^Iy. Then having lodged a fmall drop of 
this Liquor on the infide of a thin Glafs Tube, I fitted 
the Tube on to the Air-Pump, and placed a MicroB 
cope by it, fo that I could fee the Blood>Globules 
through the Tube. This being done, I caus’d the 
Tube to be exhaufled, keeping my Eye upon the Glo- 
bules all the time, in order to obferve whether they 
dilated themfelves, as the Air was withdrawn ; but 
could not perceive the lead alteration, they appearing 
exadly of the fame bignefs in the Facuum^ as they 
had done before. Whereas if they had been fill’d with 
an Elaftick Fluid, they would either have burft, or 
have been dilated to at lead 70 or 80 times their 
former Magnitude. The Stop- cock being afterwards 
turn’d, and fuffer’d to re-enter the Tube, the 
Blood-Globulesdillretain’d the fame bignefs, as in Facuo, 
To this it will perhaps be objedled, that a learned 
Member of this Society, in a Book lately pubiifh’d, has 
aflerted the diredi contrary to what I here affirm, and 
has afiur’d us, that the Blood’Globules in an exhauded 
Receiver, indantly fwell, and dilate themfelves fo, as 
to become incredibly large. But as that Gentleman 
does not tell us, upon what Experiment this affertion 
is grounded, it may not be unreafonable to fuppofe, 
that he was milled by the common Hypothefis, which 
he there maintains, of the Blooa-Globules being fill’d 
with Air, and by what he has heard or feen of the 
bubbles of Air, which arife from Blood in the Air Pump in 
the fame manner as from other Liquors, and which not 
cafily breaking out from fq a Fluid; cccafion 
