THE MICROSCOPE IN PATHOLOGY. 



291 



(1.) Scirrhus. Hard, fibrous, or chronic cancer. This is 

 characterized by the large amount of its stroma and its 

 chronic growth. At the external surface of a scirrhus 

 tumor the microscope shows cells of indifferent, or granu- 

 lation, tissue infiltrated among the muscular or adipose 

 tissue of the part affected. At a little greater distance 

 within these cells have developed into nests of cancer- 



FIG. 237. 



Carcinoma hepatis. The production and structure of diffuse medullary cancer. The 

 vascular network forms the first foundation of the stroraa, while the liver-cells are con- 

 verted into cancer-cells, a. Normal liver-cells, c. Parenchymatous inflammation, b. 

 Nests of cancer-cells, v. Vena centralis. 1-400. After EINDFLEISCH. 



cells, while the interstitial inflammation has produced an 

 abundant stroma from the growth of pre-existent connec- 

 tive tissue, the trabeculae of which are pressed asunder 

 by the advancing cell-formation. Nearer the centre we 

 find the cancer-cells in a state of retrogressive metamor- 

 phosis, producing a diminution in the size of the alveoli, 

 and leading to a puckering of the external surface of the 

 tumor. Fig. 238 exhibits each of these stages. 



