( 1002 ) 
Thefe Experiments however having hitherto pad 
uncontroverted, and it appearing from them, chat the 
fpecifick Gravity ot Serum was greater than that of 
Blood in the proportion of 1190 to 104O or of 8 
to 7 nearly ; it was a necdfary confequence of rhis, 
that the Blood Globules were fpecificaliy lighter than 
the Serum, and that in a very great degree, confide- 
ring the fmall proportion, that the bulk of the Craffa- 
mentum was found to bear to that of the Strum, {tova 
other Experiments. 
From this it was not improbably conjedured, that 
thefe Globules were thin Veficles fill’d with an Aereal 
fubftance : and this Opinion feem’d to receive a great 
confirmation, upon it’s being obferv’d, in viewing the 
Circulation by a Microfeope, that a Blood Globule, in 
pafiing through a very narrow Vefiel, would change 
its fhape from a Globular to an Oval Form, and would 
recover it’s former Figure, as Toon as it was got thro’ 
the narrow Paflbge; which appearance feem’d to be na- 
turally accounted for from the Elafticity of the included 
Aura., 
Upon this conjedure have been built a great many 
Solutions of the Fhxnomena oblcrvable in the Animal 
Oeconomy, and the dilbrders of it ; particularly a late 
ingenious account of Mufcular Motion, It it net my 
bufinefs at prefent to examine any of thefe, nor is it 
my defign to cad any refledfion upon their Authors, 
who were led into this miftake by the natural confe- 
quence of a matter of Fad, for the truth of which they 
had To great an Authority, as that of the excellent Per- 
fbn above-mentioned. But I hope, I lhall eafily be 
pardon’d for enquiring into the found nefs of the 
Foundation, when the Superftrudure ereded thereupon 
is fo confiderable ; and the following Experiments, 
however trivial in themfelyes, will not appear unworthy 
the 
