340 



TUMORS. 



and the atypical may look like young connective-tissue cells or even 

 lymphocytes. It is in the topography, together with the general charac- 



FIG. 186. CANCER CKLLS INFILTRATING THK TISSUE SPACES IN THE VICINITY OF A TUMOR OF THE 



MAMMA. 



From carcinoma mammae. Somewhat diagrammatic. 



ters of the cells and the situation of the growth, that we must seek for 

 the evidences of the nature of such tumors. 



The carciuomata are very prone to local extension, the advancing 

 tumor cells in the periphery making their way through the lymph spaces 

 and forming new foci (Fig. 186). Metastasis is of frequent occurrence 



r\fi?i \'-V\ : 



P*Ja - *-* 



Fro. 187. A GROWTH OF CARCINOMA CELLS IN A LYMPH-VESSF.L NEAR A TUMOR. 

 Such cell masses are liable to be detached and carried along the vessel, forming metastases. 



in some forms, and takes place jhiefly, though not exclusively, through 

 the lymph-vessels (Fig. 187), frequently involving adjacent or remote 

 lymph-nodes (Fig. 188). The growth of the tumor cells in the lymph- 



