( 1012 ) 
5from the Craffamtntum^ is about one half of the whole 
Mafs. The remaining Crajfamentum confifis of the 
Blood Globules, and a quantity of Serum filling up the 
Interftices between them ; which, if the Globules keep 
their Spherical Form, may eafily be found by the prin- 
ciples of common Geometry, to be nearly one half of 
the bulk of the Craffamentum: but if the Globules by 
their prefTure againfl one another change their Figure, 
the quantity of Serum will be fomething lefs. 
If this quantity of Serum lying between the Blood 
Globules be added to that pour’d off. it appears, that 
the Serum contain’d in Blood is about *- of the whole 
bulk, and confequently that the Blood Globules make 
about ~ of the whole. From which we ftiall find the 
Specifick Gravity of the Blood Globules to be to that of 
Water as iix6 to looo. 
If we fuppofe the Blood Globules to make f, 
or I of the whole bulk, their Specifick Gravity will be 
refpe< 3 ively 1174, 1150, noz, or 1078. So that 
upon any of thefe Suppofitions, the Specifick Gravity 
of the Blood Globules will be confiderably greater than 
that of the Serum, and confequently they cannot be 
fuppos'd to be Veficles fill’d with an Aereal Subftance. 
It will therefore perhaps be>askt, What do they re- 
ally confifl of ? 
In order to come to a Solution of this Quedion, it 
may be proper to take notice. 
That Blood is compos’d of Phlegm, Oil, Volatile 
and fixt Salts, and Earth. For as to the Spirit, we 
look upon it with Mr. Boyle, to confift of the Phlegm 
and Volatile Salt united together. 
That the Serum, upon a Chymical Analyfis, exhibits 
a great deal of the firft of thefe, and the others in a 
Tery fmall quantity. 
That 
