138 



Disturbances of Circulation. 



trates the mass ; and in the site of the clot there is formed a 

 mass of connective tissue. These changes are known under the 

 term organization of the thrombus. The vessel in the situation in 

 question is converted into a solid cord, its lumen completely 

 obliterated ; and as a result of shrinkage of the newly formed con- 

 nective tissue the part eventually may be seen as a thin string-like 

 obliterated section of the vascular tube. Now and again spaces 



Fig. 7. 



Embolism of branches of the pulmonary artery ; the superior embolus almost com- 

 pletely adherins; to the vessel walls and shmmken. Somewhat reduced. 

 (After Thoma.) 



are left in the connective tissue, however, through which blood in 

 some degree may pass. 



If a thrombus or a portion of a thrombus should break away, it 

 is carried forward with the blood current and must find lodgment 

 at some point where the calibre of the artery is less than the diam- 

 eter of the floating mass. The latter is then spoken of as an 

 embolus, and the process as embolism. Detachment is especially 

 likely to take place in connection with softening of a thrombus, in 

 Vv hich process the clot may easily crumble : however, even entire 



