REPARATOKY INl'LAMMATIOX IN ARTERIES. 1 1 



nia ; highly refractive, very distinct, also apparently unaltered. 

 p. Thick layer of colorless cells closely adhering to each other 

 and to the elastic layer of the intima, entirely filling up the 

 crypts made by the folds of tlie latter; dissociation demon- 

 strated these cells to be of the same general character as those 

 described above. The section has passed through the sides of 

 the plastic cup or clot. 



Prei)arations from this same series thirtj^-six hours old, in 

 the main presented similar characteristics. It is only neces- 

 sary to remark that the thickness of the plastic clot at the 

 bottom and sides of the arterial stump had considerably in- 

 creased, and that a comparatively greater number of the cells 

 had assumed the oval or spindle outline. The cellular infil- 

 tration of the adventitia and surrounding connective tissue 

 had become much more decided. Now, also, one could speak 

 a little more positively concerning a slight irritation of the 

 protoplasm immediately outside of the elastic layer of the 

 intima. The elastic layer itself still showed no change ; neither 

 did the muscular elements of the media. 



Of the same series, the preparations next in order of date 

 are those containing thrombi forty-eight hours old. Careful 

 study of these demonstrated the following. The cells of the 

 plastic clot presented changes which were a progression of 

 those already noted in the two younger clots. The size of the 

 plastic clot was found to be considerabl}' increased. Some of 

 the cells constituting it were spindle-form, and numbers of 

 them now possessed one, sometimes two or even more, slender 

 and somewhat lengthened pi'ocesses. Occasionall}- two or more 

 cells were united together by a long process, and then a tend- 

 enc}' to the formation of a cellular network could be made 

 out. The nucleus of many was oval or oblong, and frequently 

 there were two or more round nuclei in the cell. The clastic 

 bands of the tunica intima were still to be seen near the bot- 

 tom. These and the elastic laj-er of tlie intima in its proper 



