[ 37i ] 
feme called the fibrous part of the blood, or the 
gluten, but by others with more propriety termed 
the coagulable lymph ; and of another, which gives 
the red colour to the blood, and is called the red 
globules. Thefe two parts can be feparated by 
wafhing the crajfamentum in water, the red particles 
difiolving in the water, wliilft the coagulable lymph 
remains folid. That it is the coagulable lymph 
which by its becoming folid gives firmnefs to th'c 
crajfamentum , is proved by agitating frefh blood with 
a flick, fo as to collect this coagulable lymph on 
the flick, in which cafe the reft of the blood remains 
fluid *. 
The furface of the crajjamentum , when not 
covered with a cruft, is in general of a more florid 
red than the blood was when firft taken from the 
vein, whilft its bottom is of a dark colour, or blackifli. 
This floridnefs of the furface is juftly attributed by 
fome of the more accurate obfervers to the air, with 
which it is in contact ; for, if the crajfamentum be in- 
verted, the colours are changed, at leaft that which 
is now become the upper furface aflumes a more florid 
rednefs. This difference of colour, others have endea- 
voured to explain from the different proportions of 
* It may be proper to mention here, that till of late the 
coagulable lymph has been confounded with the ferum of the 
blood, which contains a fubflance that is likewife coagulable. 
But in thefe papers, by the lymph, is always meant that part of 
the blood which jellies, or becomes folid fpontaneoufiy when 
blood is received into a bafon, which the coagulable matter 
that is dilTolved in the ferum does not ; but agrees more with 
the white of an egg, in remaining fluid when expofed to the 
air, and coagulating when expofed to heat, or when mixed with 
ardent fpirits, or fome other chemical fubftances. 
Bb b 2 
the 
