THROMBOSIS. 



229 



organisation, a permanent, but a transitory phenomenon, and 

 passes straightway into the opposite condition, that of softening 

 and liquefaction ; accordingly we find at a certain stage in the 

 process a yellow fluid not unlike pus occupying the interior of 

 the clot, and enclosed in a comparatively tough, flesh-coloured 

 layer which adheres firmly to the wall of the vessel. The cir- 

 cumstance that softening occurs chiefly in laminated thrombi 

 gives rise to various modifications in the anatomical appearances. 

 The strata of colourless corpuscles sometimes exhibit a singular 



Fig. 73. 



Part of a transverse section tlirougli an arterial thrombus three 

 months old. a. Middle coat (its innermost layers only) ; 

 h.y Lamella which separates the middle from the inner 

 coat ; c. Intima ; d. Line of demarcation between the 

 intima and the thrombus ; e. Thrombus ; /. Vessels cut 

 across ; epithelium very distinct. 3^7;. 



proneness to take part in the softening, while at others they 

 offer the longest resistance to disintegration. In the former 

 case, the connexion of the colourless cells with one another is 

 early broken. Even before the red corpuscles have had time to 

 part with all their colouring matter, the thrombus breaks up 

 into a reddish-grey pulp which may resemble anything between 

 chopped meat and the lees of wine. 



If on the other hand the white corpuscles offer a more deter- 

 mined resistance than the red ones, we first of all get a mass of 

 cheesy colour and consistency, passing at a later period into a 

 more spongy or loculoso decomposition of the whole of the 

 softening thrombus. 



