536 



TUMORS. 



(c) The variety called medullary cancer is the most malignant. 

 It shows the following features : 



The epithelia are very large and irregular in shape ; sometimes 

 they are of a polyhedral form and partly nucleated, sometimes 

 homogeneous and shining. They exhibit endogenous multipli- 

 cation in the shape of so-called mother cells, and also multiplica- 

 tion .effected through wedges which spring from the living matter 



FIG. 222. EPITHELIOMA OF THE PREPUCE. 



E, epithelial pegs ; N, epithelial nests, with a concentric arrangement of the epithelia in 

 the centers of the pegs and nests ; P, so-called cancer-pearl in the center of the nests and 

 pegs; C, connective tissue, crowded with medullary or inflammatory corpuscles. Magnified 

 200 diameters. 



in the cement-substance. The connective tissue is scanty ; it is 

 fibrous in character, and incloses large and small groups of epi- 

 thelia in closed alveoli. (See Fig. 223.) 



The characteristic feature of what we call medullary cancer 



