2 
Of the Circulation of the Blood. 
Buies, which are compreffible into any flhape, and' in 
continual motion, may, by finking againft each other, 
Compofe one large globule of a perfectly fpherical figure, 
one of which, and five of the {mailer fort, as they appear 
in contact, the fixth lying behind, is reprefented fig. 29. 
which, by their mutual attraction to, and preffure again ft 
each other, readily unite to form a perfe&ly round body, 
as at fig. 30. Their attraction towards- each other is fo 
confiderable, as to form a kind of flefhy fubftance, when 
brought into contact 5 and their fpecific a gravity more 
than the ferum in which they float. 
How thefe globules, and alio the more minute ones of 
which they are compofed, are occalionally feparated, in 
order to pafs through extremely minute veffels, which 
without fuch a reparation they cannot poffibly enter, 
and how they re-unke again in veffels where they have 
more room, is eaf-ly comprehended by a due confidera- 
tion of the two foregoing figures. 
The diameter of a common round globule of human 
blood, is equal to the 1940th part of an inch. 
In order to view the blood with the microfcope, upon 
the tip of an hair pencil, take a fmall drop of warm 
blood, immediately as it comes from the vein, and 
fpread it as thin as poffible upon the object-carrying 
glafs of the microfcope, and apply it between the 
objeT plate and fprings, to the firft and fecond mag¬ 
nifiers. It may alfo be extreamly well examined, if 
a little of it be taken up into a fmall, but very thin 
capillary tube, which being held in the nippers of the 
apparatus, may be readily applied to the magnifier. 
If you dilute a drop of bood with warm water, and 
apply it either of thefe ways to the magnifier, fome 
of the larger globules will be feparated from each 
other, 
Phil, Tranf, No. 361. 
