54 THE TONER LECTURES. 



joining tunica intima, there ma}'' be no very inconsiderable 

 number of endothelial cells detached from the arterial wall 

 above, and but little changed. 



C OX CLU SIGNS. 



The foregoing study has led me to the following conclu- 

 sions : — 



1st. After the ligation of an artery, if the first collateral 

 branch above is sufficiently distant, a blood coagulura generally 

 forms at the bottom of the arterial stump, but not always. 



2d. The formation of this blood coagnlum, when conditions 

 are favorable to healing, is not sudden. Frequently the struc- 

 ture of this fibrinous clot proves it to have been deposited at 

 interrupted intervals. The blood-clot is, therefore, often larger 

 some hours or days after its first formation, than when it is 

 first deposited. See Fig. 2. 



3d. The portions of the fibrinous clot which have been 

 deposited at interrupted intervals have usually a stratified 

 aspect. The blood-clot is not homogeneous in structure. 



4tli. The blood or fibrinous clot does not undergo a genuine 

 oro-anization or vascularization. It acts onlj' as a temporary 

 barrier to the course of the blood, and as a foreign body, 

 whose tendency is first to pi'oduce a certain amount of irrita- 

 tion in the adjacent internal coat of the vessel, and to finally 

 disappear after slow disintegration. 



5tli. The healing of an artery ligated after the ordinary 

 method is effected by the organization, vascularization, and 

 subsequent cicatricial metamori)hosis of a plastic formation 

 which grows between the blood-clot and the ligature, and which 

 is mainly composed of colorless endothelioid cells. 



6th. The origin of the cells of the plastic clot is to be 

 referred chiefly to a proliferation of the endothelium and sub- 

 jacent cellular elements of the tunica intima, between the point 



