REPARATORY IXFLAMMATIOX IN ARTERIES. 39 



would occasionall}' be seen extending toward the intima, but 

 would not be observed to reach the latter. 



At this time, however, there was no tendency' of an}' vessel 

 to pass into the now thoroughly vascularized clot from the 

 media, by penetrating, at the sides of the clot, the well-defined 

 elastic layer of the internal lining of the arterial walls. 



The last study of this series was made upon preparations 

 from the femoral arteries of dogs, twenty and twentj-'five da3-s 

 after ligature. 



All that need be said of the thrombi twenty- days old is 

 that the two previously mentioned modes of growth of the 

 plastic clot had reached a still further development. A com- 

 ])lete anastomosis between the vessels of the clot and those of 

 the walls had now been established at the bottom of the clot, 

 bv the before-mentioned varices sending toward each other 

 capillar}' loops, which passed through ruptures in the intima, 

 and which united together forming a network. Even now 

 there was no visible advance toward the establishment of a 

 vascular anastomosis between the vessels of the walls and 

 those of the clot directly through the sides of the artery. 

 At the sides of the vessel the elastic loyer of the intima still 

 appeared to be intact, or but little softened. The end of tiie 

 artery had already begun to shrink by reason of the transition 

 of the spindle-cells of tiie organized clot into cicatricial tissue. 

 As this contraction continues the stump of the artery assumes 

 a conical shape, and the organized clot slowly disappears by 

 cavernous transformation. 



In those blood-clots twenty and twenty-five days old which 

 are found attached to the top of the plastic clot, no decided 

 metamorphoses are yet observable. The red disks often 

 have not even become decolorized or shrunken. Those blood 

 coagida which become occupied by trabecule of the plastic 

 clot generally nt this dnte have disappeared, the only remains 

 of tlicm being small masses of colored granules occupying 



