548 
THE CROONIAN LECTURE ON THE COAGULATION OE THE 
BLOOD, DELIVERED BEEORE THE ROYAL SOCIETY, 
JUNE 11, 1863. 
By Joseph Lister, Esq., F.R.S., F.R.C.S. 
[Continuedfrom p. 436.) 
It may not be altogether superfluous to mention some other 
facts illustrative of the active influence of ordinary matter in 
promoting coagulation, and the negative character of the 
lining membrane of the vessels. I find that a needle 
introduced into one of the veins of the foot of a sheep for a 
much shorter period than is necessary to produce the first 
appearance of the actual deposit of fibrin upon it, leads after 
a time to coagulation where the needle had lain; in other 
words, that a foreign solid, by a short period of action on the 
blood, brings about a change that results in coagulation, 
though the blood still lies in the living vessels. I have also 
ascertained that after blood has been made to coagulate in a 
particular vessel by introducing a needle into it, if the 
coagulum as well as the .needle is removed, and more fluid 
blood is allowed to pass in, this blood remains fluid for an 
indefinite period, showing that the needle had not impaired 
the properties of the vessel by its presence ; so that the pre¬ 
vious coagulation must be attributed, not to any loss of 
power in the vein, but simply to the action of the foreign 
solid. 
In seeking for an analogy to this remarkable effect of ordi¬ 
nary solids upon the blood, we are naturally led to the 
beautiful observations of Prof. Graham, lately published in 
the ( Philosophical Transactions/ He has there shown what 
insignificant causes are often sufficient to induce a change 
from the fluid or soluble to the “pectous,” or insoluble con¬ 
dition of “ colloidal” forms of matter. Indeed, Mr. Graham 
has himself alluded to the coagulation of fibrin as being pro¬ 
bably an example of such a transition. 
There is, however, another remarkable circumstance that 
must be taken into consideration, of which I myself have 
been only recently aware, and which may be new to several 
Fellows of the Society, and that is, that in spite of the in¬ 
fluence of an ordinary solid the liquor sanguinis is not capable 
