'04 RESEARCHES ON THE COAGULATION OF THE BLOOD. 
rinary College, I tied into the right jugular vein, one end of 
a piece of vulcanized India rubber tube, four yards in length 
the greater part of which was coiled up in a freezing mixture 
and some of the blood, having been allowed to remain for a 
while in the tube, was shed into vessels standing in ice-cold 
water. Its temperature on first escaping into the air was 39T 
Fahr., and having been since kept in the cold, it is still only 
partially coagulated at the present time (twenty-nine hours 
after it was shed). At first, however, it appeared as if we 
were likely to fail, the blood of this horse being a rare excep¬ 
tion to the general rule, in exhibiting for a long time no ap¬ 
pearance of the “ sizy” layer. But after it had stood for about 
two hours, I succeeded in removing from the surface, by means 
of a glass tube, a sufficient amount of liquor sanguinis for the 
performance of an experiment, taking care that the glass into 
which it was shed, and the tube, were both near the freezing 
point. To half a drachm of this plasma, I now added one 
minim and a half of moderately dilute acetic acid, which had 
the effect of rendering it distinctly acid, as indicated by its 
communicating a red tint to litmus, and restoring the colour 
of turmeric paper which had been reddened by dipping it in 
the portion of the liquor sanguinis which had not been acidu¬ 
lated. I kept the specimen in ice-cold water till this evening. 
For a long time it remained perfectly fluid, except the forma¬ 
tion of a little soft coagulum at the surface, just as in the 
unacidulated blood; but a few drops placed in a watch-glass 
and brought into a warmer atmosphere, coagulated in about 
the same time as the blood that first flowed from the tube, a 
soft clot forming in about a quarter of an hour. Even at the 
expiration of twenty-four hours, a portion of what remained 
in the cold was still fluid, though faintly acid, but set into a 
pretty firm clot on being removed into a warmer situation. 
[“Mr.Lister nowproceeded to perform a similar experiment 
before the Society. A glass containing some liquor sanguinis 
of the horse’s blood shed twenty-nine hours before, was taken 
out of the mixture of ice and water in which it stood, and 
the contents were seen to be still to a considerable extent fluid, 
although acidulated with acetic acid two hours previously. 
A portion of the liquid was poured into a watch-glass, and, 
having been shown to be acid by litmus paper, was set aside 
to coagulate, and about a quarter of an hour later was ex¬ 
hibited as a soft clot. Mr. Lister then continued—] 
“ From these facts it is obvious that the ammonia 
theory utterly fails to explain the influence of temperature 
on coagulation. The circumstance that the liquor sanguinis 
was acid in this experiment, is clear proof that it contained 
