694 
ON THE CAUSES OF COAGULATION OF THE BLOOD IN 1 
DISEASES OF THE BLOOD-VESSELS. 
By Joseph Lister, Esq., E.E.C.S. Eng. and Edin. 
( Continued from page 508.) 
The application of ammonia occupied three quarters of a 
minute, and three quarters of a minute later the blood was again 
allowed to flow through the vessel, having been arrested alto- 
gether a minute and three quarters. A short time having been 
allowed for the evaporation of the ammonia, the edges of the 
wound were brought together by stitches. At 4*58, or an 
hour and three quarters later, the wound having been opened, 
the flow was again obstructed as before, and the vein was 
rapidly slit up. A small amount of dark coagulum escaped 
with the fluid blood. The interior of the vessel was now 
immediately examined. A valve with three flaps, about the 
middle of the open portion, was rendered conspicuous from 
the fact that a black coagulum existed between each of the 
flaps and the wall of the vessel; and on careful observa- 
tion of the lining membrane of the vein in other parts, it was 
seen to be dotted over in patches with fine granular deposits 
of pink fibrine, which could only be detached by firmly 
scraping with the edge of the knife, reminding me precisely 
of the close adhesion of the clot which occurred in the pop- 
liteal artery in the case which I related at the commencement 
of this paper, and which is known to be characteristic both 
of arteritis and phlebitis. Here it is clear that the coats of 
the vessel having been deprived of their vitality, the blood 
flowing through it assumed the same chemical tendencies as 
we have seen it to possess when removed from the body ; and 
those parts of the fluid which remained at rest under these 
conditions, namely, the motionless layer of liquor sanguinis 
next to the lining membrane, and the portions of blood in the 
sinuses of the valve, underwent coagulation, yielding up 
their ammonia through the permeable coats of the vein. 
And I think we need not hesitate to admit that similar 
occurrences take place in the early stages of arteritis and 
phlebitis, the coats of the vessels being in those cases not 
dead, but impaired in vital energy by inflammation. 
A similar explanation appears to account for the early 
formation of coagula in the vicinity of a ligature placed upon 
an artery. It has been seen how utterly the usual explana- 
tion, that of the quiescence of the blood, fails to account for 
