38 THE TONER LECTURES. 



serves a parallelism to the axis of the granulation. The sur- 

 face of the granulation is covered with one or two layers of 

 epithelioid cells ; not the slightest sign of a capillary loop 

 occupying the axis of the granulation, nor the Isast trace of a 

 vessel to be seen anywhere in the inner layers of the media, 

 preparing to send a vascular loop through the elastic layer of 

 the intima. 



It could not be found that the clot possessed any vascular 

 communication with the vasa vasorum at this stage. The 

 blood which permeated the plastic clot travelled by wa}- of the 

 previously mentioned capillaries and blood-channels, and was 

 supplied from the open artery above the thrombus. 



Preparations from thrombi fifteen days old exhibited only a 

 more complete development of the conditions shown to be pres- 

 ent in the last-discussed stage of organization. I wall merely 

 add that the blood coagulum, when lifted up from its proper bed 

 by the growth of the plastic clot, still remained, at tliis date, 

 as at first formed. No changes other than those of the inevi- 

 table consequences of contraction of the fibrin were to be re- 

 marked. The clots were attached to the top of the organized 

 or plastic clot only by their base. When, on the other hand, 

 the blood-clot had remained in its primitive position, firmly 

 attached to the w^alls of the arter}-, the previousl^^ mentioned 

 granulations had so increased in number and size as to cause, 

 probably by pressure, a progressive degeneration of the red 

 blood disks, and their slow disappearance by granular disinte- 

 gration and absorption. Preparations for the establishment 

 of an anastomosis between the vessels of the clot and those 

 of the walls were now for the first time definitely observed. 

 The capillaries at the bottom of the plastic clot had by cavern- 

 ous dilatation become enlarged almost into sinuses. Opposite 

 to those enlarged capillaries, be^yond them, and on the other 

 side of the intima and media, similar varices had been formed 

 from the vasa vasorum. A loop from one of these varices 



