224 KANSAS UNIVERSITY SCIENCE BULLETIN. 



DESCRIPTION OF OUTLINE SKETCHES AND DRAWINGS. 



Cell Nest 8, "A" (fig. 10) . The amount of necrotic material 

 in this figure is greater than in the following ones, the necrotic 

 plug showing less and less in each consecutive section. There 

 are no divisions shown in this figure near the necrotic plug, 

 but the nearest two are direct. The greater part of the divid- 

 ing cells are in the limb of the nest. 



Cell Nest 8, "B" (fig. 11). The number of divisions pres- 

 ent in the distal part of the limb is noticeable. There are three 

 direct divisions immediately adjacent to the necrotic plug and 

 one nearer than the nearest indirect division. 



Cell Nest 8, "C" (fig. 12). In this nest there was an un- 

 usually large number of dividing cells. At the point of the 

 arrow in figure 12 is the center of the group of cells drawn on 

 a large scale in figure 13. About the arrow point are the four 

 direct divisions and the two indirect divisions shown in the en- 

 larged group. This group of nineteen cells includes a larger 

 area under the lens than any previously drawn. I drew all the 

 cells of importance under the field of the camera lucida, in- 

 cluding a field .05 mm. in diameter, while the previous groups 

 drawn have included an area only .0375 mm. in diameter. It is 

 located on the edge of the necrotic area and includes the whole 

 width of cells lying between this area and the free edge of the 

 cell nest, cell F being in the first row of the nest, while cell B is 

 among the necrotic cells. The direct divisions of this section 

 are deep in the center of the nest, while the indirect are 

 largely very close to the edge, seven cells out of twenty-five 

 dividing indirectly lying in the first row and no directly di- 

 viding cells nearer than the second row, and then only one. 

 A general survey of these sketches together with the tables 

 strongly indicates that the cells on the edge of the tumor 

 increase almost, if not wholly, by indirect divisions, while those 

 deeper away from the edge increase largely by direct divisions 

 but occasionally by indirect. I want to emphasize by the large 

 drawings the intimate association of the directly dividing cells 

 with the degenerate ones. Cells H, H', H" are the "chromatic 

 cells" that I have described previously under figure 13. Sur- 

 rounding these cells closely are cells A, B, C, D and E, plainly 

 in the process of direct division. Cell B is peculiar in that it 

 shows no chromatin nucleolus in either segment of the 

 nucleus. This same occurrence was noticed in numbers 



