106 NOTICE OF FURTHER RESEARCHES 
hours freely exposed to the air, but being situated in an uninjured part of a 
blood-vessel, had remained free from coagulation. 
Further, in the opening meeting of last Session I demonstrated another 
important principle, viz.—That ordinary solid matter, unlike atmospheric air, 
induces coagulation of blood in its vicinity when introduced within the living 
vessels. Having inserted a piece of clean silver wire for a considerable distance 
into one of the veins of an amputated sheep’s foot, I slit up the vessel after 
a short time had elapsed ; when I exhibited a coagulum extending along the 
whole length of the foreign body, whereas a mere wound of the vein failed to 
induce a clot except immediately at the spot where the injury had been inflicted. 
It was obvious that the introduction of the wire could not affect the amount 
of ammonia in the blood; and from this and many other facts, to which I need 
not here allude,t I was led to the opinion, that as regards what takes place 
within the living vessels, the ammonia theory might practically be left entirely 
out of consideration. 
What I have to show this evening will, I think, prove that even for blood 
outside the body, the ammonia theory, whatever degree of truth it may contain, 
is very far indeed from representing the whole truth. 
One of the most remarkable circumstances connected with blood that has 
been shed from the vessels is, that it refuses to coagulate below a temperature 
of 40° Fahr. or thereabouts. This is explained by Dr. Richardson on the hypo- 
thesis that the low temperature prevents the evolution of ammonia,’ while 
the rapidity with which coagulation takes place at high temperatures seems 
to him satisfactorily accounted for by the increased volatility exhibited by the 
ammonia under such circumstances. I was myself at first disposed to accept 
this interpretation, but subsequent reflection led me to think that, to say the 
least, it required confirmation. It occurred to me that if it were true that the 
fluidity of blood below 40° was due to free ammonia retained in it, coagulation 
would take place immediately, in spite of the cold, if the alkali were neutralized 
by the addition of acid, provided the fibrine were not impaired in its coagu- 
lating property by the reagent employed. In order to ascertain whether this 
result would really follow, I poured blood freshly shed from a sheep into vessels 
surrounded by ice-cold water, and by this means succeeded in keeping some 
portions of it fluid for a considerable time, and found that it continued liquid 
notwithstanding the addition of dilute acetic acid in what I supposed must be 
* For some of these facts see ‘On the Early Stages of Inflammation,’ Philosophical Transactions 
for 1858, pp. 673, et seq. 
* See Dr. Richardson’s Astley Cooper Prize Essay, p. 303, where a fact is mentioned, indicating 
that no ammonia was given off at 34° Fahr. from a specimen of blood which had been artificially am- 
moniated, and which at 96° afforded distinct evidence of evolution of the alkali. 
