TUMORS. 



537 



is, therefore, the large number of epithelial formations in com- 

 parison with the connective tissue, the coarse granulation of the 

 epithelia giving them the appearance of bright, homogeneous 

 lumps i. e., solid masses of living matter, indicating an active 

 morbid growth of epithelia. The compact lumps of bioplasson 

 often appear as medullary corpuscles ; the more rapid the growth 

 of the tumor, the greater is the increase of the corpuscles and the 

 more malignant the type of the growth. In the worst tumors 

 of this kind, we can barely trace under the microscope fully 

 developed, nucleated, polyhedral epithelia, arranged in nests ; 

 the main mass of the tissue is constructed of elements closely 



z-f 



FIG. 223. MEDULLARY CANCER OF THE PAROTID GLAND. 



E, regularly developed, polyhedral, nucleated epithelia, which at H, by increase of their 

 living matter, have become shining and homogeneous ; M, medullary corpuscles in a space 

 inclosed by living matter (so-called mother-cell) : L, vacuolation of epithelia; F, scanty con- 

 nective-tissue frame. Magnified 600 diameters. 



crowded together, exhibiting all the features of medullary cor- 

 puscles, and rendering the tumor a myeloma rather than a 

 cancer. Transition of cancer into myeloma under these circum- 

 stances is often observed. An originally well-developed scirrhus 

 may gradually assume the character of a medullary cancer, and 

 this the features of myeloma, In the clinical variety of carcinoma 



