TUMORS. 365 



or even more nuclei are observed. The intercellular substance is 

 more abundant and more distinctly nbrillated than is the case in 

 the small round-cell sarcomata, but it is not uniformly distributed 

 between the individual cells. These are usually aggregated in 

 groups, which are surrounded by the denser bands of fibrous tissue. 

 From these, little fibrous twigs may sometimes be seen penetrating 

 between the individual cells of the group. This arrangement gives 

 sections of the growth an alveolar appearance (Fig. 328). The 



Large round-cell sarcoma of the tongue : a, large round cell containing three nuclei ; 6, 

 delicate fibrous stroma supporting the cells of the growth. At the point b this stroma 

 contains a collapsed capillary bloodvessel. The large round cells are probably of endo- 

 thelial origin. The growth occurred in a man aged sixty-one years, and in the course of 

 eight months had attained the size of a hickory-nut. 



fibrous tissue itself may be highly developed, resembling the adult 

 form ; or it may be more highly cellular and contain large spindle- 

 shaped cells. When this is the case the tumor becomes a mixed- 

 cell sarcoma composed of large cells, partly round, partly fusiform. 



The large round-cell sarcomata spring from the same tissues 

 that give rise to the small round-cell sarcomata, but it is probable 

 that they owe their production in large measure to a proliferation 

 of the endothelial cells of those tissues, and are, therefore, etiologi- 

 cally related to the endotheliomata. They grow less rapidly than 

 the small round-cell and lympho-sarcomata, and, as would be ex- 

 pected from a study of their structure, they are less prone to 

 infiltrate their surroundings or to be subject to metastasis. They 

 are, to a corresponding degree, less malignant in their clinical mani- 

 festations. 



d. SPINDLE-CELL SARCOMATA. The shape of the cells of this 

 group of tumors betokens a higher state of differentiation than is 

 found in the small round-cell sarcomata, the cells having more 



