492 



TUMOES. 



melanoma. The presence of pigment alone is not sufficient to characterize 

 the nature of the tumor. There is, however, no objection to calling a tumor 

 which contains sand-like bodies an " arenoid fibroma, angioma," etc., and a 

 tumor which contains pigment granules a " melanotic fibroma, myeloma," 

 etc. 



5. MYELOMA OB SARCOMA. 



The special character of this group of tumors was first 

 determined by Virchow. He considers the structure to be con- 

 nective tissue in an embryonal or medullary condition, without 

 any epithelial elements, and thus sharply marked from cancer. 

 All later researches have corroborated Virchow's views. We 



FIG. 190. ARENOID MYXOMA (PSAMMOMA, VIRCHOW) OF THE 

 DURA MATER. 



T, trabeculse of fibrous connective tissue, holding partly sessile, partly pediculated, arenoid 

 corpuscles, A, or elongated calcareous formations, C. Magnified 50 diameters. 



define sarcomata as Virchow defined them that is, connective- 

 tissue tumors, in which very little or no basis-substance is 

 developed. We object, however, to the word " sarcoma," as this 

 means fleshy tumor, and would substitute for it the old term 

 "myeloma," viz., medullary tumor, as this accords better with 

 the histological features. 



Virchow divided sarcomata into the following varieties: 

 (a) net-ceil sarcoma; (~b) spindle-cell sarcoma; (c) round-cell 



