TUMORS. 



FIG. 319. 



357 



Endothelioma from the floor of the mouth. (Earth.) Section showing the advance of the 

 growth into the lymph-spaces : a, karyokinetic figure in an endothelial cell. Other less 

 well-preserved figures are seen in other portions of the section. 



intercellular substance. This is more particularly the case when 

 the endothelial cells in the adventitia of the bloodvessels mul- 



FIG. 320. 



Early stages in the formation of a psamuioma. (Ernst.) a, collection of endothelial cells; 

 b, similar group showing imbrication of the cells and beginning hyaline degeneration ; c, 

 hyaline mass containing a slight deposit of infiltrated calcareous matter, appearing as 

 granules. 



tiply to form the growth. The cells of the growth are then in 

 intimate relation with the walls of the vessels, and the tumor is 



