[ 377 ] 
indeed been faid, that the cold alone coagulated it , 
for, fay they, if you receive blood into a bafon, and 
keep that bafon in warm water, and ftir the blood 
well, it can be kept fluid. But in the experiments 
from which this concluflon was made, I find there 
has been a deception. In fhort I have found that it 
coagulates as foon when kept warm, and when agi- 
tated, as it does when fuffered to reft and to cool. 
As the fubjeft feemed to me of importance, I 
have endeavoured to afcertain the circumftance to 
which this coagulation is owing, by feveral of ex- 
periments, in each of which the blood was generally 
expofed to but one of the fufpe&ed caufes at a time. 
Thus, in order to fee whether the blood’s coagulation 
out of the body was owing to its being at reft, I 
made the following experiment. 
Experiment IV. 
Having laid bare the jugular vein of a living dog, 
I made a ligature upon it in two places, fo that the 
blood was at reft between the ligatures } then cover- 
ing the vein with the fkin, to prevent its cooling, I 
left it in this fituation. From feveral experiments 
made in this way, I found in general, that after be- 
ing at reft for ten minutes, the blood continued fluid ; 
nay, after being at reft for three hours and a quarter, 
above two thirds of it was ftill fluid, though it coa- 
gulated afterwards. Now the blood, when taken 
from a vein of the fame animal, was completely jel- 
lied in about feven minutes. The coagulation there- 
fore of the blood in the bafon, and of that which is 
merely at reft, are fo different, that reft alone can- 
Vol. LX. C c c not 
