COAGULATION OF THE BLOOD. 
507 
fish, which had the actions of life stopped for three days, 
and was supposed to be dead, did not coagulate in the 
vessels, but, upon being exposed or extravasated, soon 
coagulated. 5 ‘The blood of a lamprey-eel, which had been 
dead to appearance some days, was found fluid in the vessels, 
because the animal was not really dead : there had, however, 
been no motion in the blood, as the heart had ceased acting; 
but upon its being exposed, or extravasated into water, it 
soon coagulated. 5 (Palmer’s edition, vol. iii, p. 32.) Hunter, 
however, does not seem to have drawn any inference with 
regard to the higher animals from these cases. He speaks 
of 4 the very speedy coagulation of the blood which usually 
takes place in all the vessels after death 5 (vol. iii, p. 27); 
and though he believed that 4 where there is a full power of 
life, the vessels are capable of keeping the blood in a fluid 
state, 5 he also supposed that some motion, though 4 very 
little, is required to keep up its fluidity 5 (ib., p. 32). Indeed, 
the expression, 4 full power of life, 5 just quoted, is quite in- 
consistent with the state of a sheep’s foot, six days after 
muscular irritability has been lost. I had myself frequently 
made experiments on inflammation upon the amputated 
limbs of frogs, and observed that the blood remains fluid for 
more than twenty-four hours after death; but muscular 
irritability, ciliary action, &c., also last in those creatures to 
a very much later period than in the higher animals, so that 
I never ventured to infer that fluidity of the blood was likely 
to continue long after death in mammalia. 
“Further observations on the feet of the sheep and limbs 
of the cat, proved even still more strikingly the influence of 
the vessels upon their contained blood. If the skin be 
reflected from over a subcutaneous vein full of blood, and 
lightly replaced, so as to protect the subjacent parts from 
evaporation without excluding the air, the vessel will be 
found, in two or three hours, changed from a dark venous 
colour to a scarlet arterial tint ; yet no coagulation will occur 
in the blood, although the oxygen of the atmosphere has 
evidently penetrated freely through the coats of the vessel, 
showing that abundant opportunity has occurred for evolu- 
tion of ammonia, provided any tendency to such an occur- 
rence existed. Again, if such a vein be cut across with fine 
sharp scissors, without disturbing its connexions, or inflicting 
much injury on its coats, the blood will be found, after about 
six hours, perfectly fluid in the vein, up to within perhaps 
one twentieth of an inch of the wound, where a small clot is 
perhaps seen, utterly insufficient to obstruct the progress of 
ammoniacal vapour. Hence it appears to me to follow, as a 
