[ 3^0 3 
the whole of the blood is not congealed in this time 
by reft alone, yet a part of it is. But as it would be 
trefpaffing too much on the Society’s time to relate 
every experiment I have been obliged to make for 
this purpofe, I (hall only mention the general refult 
of the whole. 
After fixing a dog down to a table and tying up 
his jugular veins, I have in general found, that on 
opening the veins, at the end of ten minutes, the 
blood was ftill entirely fluid, or without any appear- 
ance of the coagulation’s beginning *. If opened at 
the end of fifteen minutes, at firft fight it appeared 
quite fluid j but on a careful examination I have 
found fometimes one, and fometimes two or three 
fmall particles about the fize of a pin’s head, which 
are part of the blood coagulated. When opened 
later than this period, a larger and larger coagulum 
was obferved j but fo very flowly does this coagu- 
lation proceed, that in an experiment where I had 
the curiofity to compare more exactly the clotted 
part with the unclotted, I found, after the vein 
had been tied two hours and a quarter, that the 
coagulum weighed only two grains j whilft the reft 
of the blood, which was fluid, on being fuffered to 
congeal, and then weighed, was found to weigh 
eleven grains. I can advance nothing farther in this 
part of my fubjedt with precifion. Nor can I pre- 
tend exa&ly to determine the time at which all the 
* I fa}', in general, it was fluid at the end of ten minutes ; 
but I mult like wife mention that in one dog I found two very 
fmall particles of beginning coagulation, even at this period; 
yet in another I could not obferve any fuch appearance, even 
at the end of fifteen minutes, 
blood 
