182 
COMPTK-RENDU OF THE ALFORT SCHOOL 
The clot which the vein contains is yet black, and adheres 
already, by its whole periphery, to the internal membrane to which 
it seems fixed, as if there were a true agglutination between them; 
and it is a remarkable fact, that this adhesion is stronger in pro¬ 
portion as we examine it near the ligature. 
If we dissect the clot, we shall find that it has already begun to 
undergo some modification. It seems to be composed of the super¬ 
position of numerous concentric fibrinous layers which can be per¬ 
fectly disengaged from each other by a tolerably careful manipu¬ 
lation. 
If we follow, in a series of experiments, the different phases of the 
phenomena of the inflammation of the vein and the organization of 
the clot which it contains, we shall see that, in proportion to the time 
which has elapsed since the application of the ligature, the exterior 
cellular tissue of the vein becomes condensed as it is gradually and 
intimately mingled with the external and central membranes of the 
vessel, so that, about the twentieth or five-and-twentieth day, they 
resemble a white indurated tissue, creaking under the knife. Still 
the internal membrane preserves all its normal characters; and if 
there w’ere not a greater degree of whiteness resulting from its trans¬ 
parency which permits us to observe its subjacent white tissue, we 
should not be able to discover any difference, even at the thirtieth 
day after the ligature, between this membrane and that of a healthy 
vein. 
As for the clot, in proportion as time passes on, its structure of 
concentric layers becomes more and more evident. It diminishes 
in volume on account of the reabsorption of the liquids which im¬ 
pregnate it—it changes its colour, and becomes of a fibrinous yel¬ 
low by the disappearance of its colouring matter, and it adheres 
still more intimately to the internal membrane of the vein. 
Such, rapidly described, are the phenomena which take place in 
a vein which is the seat of adhesive or cicatrizing inflammation; 
but there are some different conditions of this obliteration with 
which it is of considerable importance for us to be acquainted. 
The first is, that the clot contained in the interior of the vein 
should be completely removed from the contact with air—that the 
exterior inflammation of the vein should be elevated to a moderate 
intensity—and that the animal shall be in good health. 
M. Renault formerly made some experiments with a view to 
prove the indispensable necessity of the absence of air in order to 
the organization of the clot in the interior of the vein. These ex¬ 
periments have been repeated during the last session, and with the 
same results. 
If the ligature of the vessel, w^hich ordinarily falls off between 
the tenth and sixteenth day, detaches itself before the clot becomes 
