214 KANSAS UNIVERSITY SCIENCE BULLETIN. 



Figure 4 is a group of twelve tumor cells drawn from cell 

 nest 1, a small nest of seventy-five cells containing six indirect 

 and no direct divisions. In this group are shown four of the 

 six indirect divisions. Cells A and B are noticeable for their 

 large size, while cells C and D are of the same size as the rest- 

 ing cells. Cell £■ is a common-sized resting cell, containing one 

 chromatin nucleolus but with a hollow clear vesicle bulging 

 into the wall of its nucleus. Cell F is a common resting cell ex- 

 cept that it has its chromatin diffused through the karyoplasm. 



Figure 5. In this group and in those following I have not 

 included all the cells that appeared in the field, but simply in- 

 structive ones and enough resting cells to show a comparison. 

 The group was drawn from cell nest 3, of 253 cells, which in- 

 cluded six indirect and five direct divisions. Cell C was in the 

 fourth tier from the edge and on the peripheral side of the 

 group. It was large, being .0125 mm. in its greatest diameter 

 and showing a nucleus in two segments, each segment con- 

 taining a regularly round chromatin nucleolus. The cell was 

 noticeably clearer than the others. Cell B also has a biseg- 

 mented nucleus, but its chromatin was scattered in irregular 

 masses through the karyoplasm. It was also large, being .01 

 mm. in its greatest diameter. The nucleus of cell A was in 

 three segments, each part having a regularly round chromatin 

 nucleolus, and beside this a certain amount of chromatin scat- 

 tered in clumps through the karyoplasm. It was .0125 mm. in 

 its greatest diameter. In all my cell measurements I used a 

 micrometer scale which I have found by measurement to give 

 the following dimensions: With a drawing board on a level 

 with the object and at the same inclination as the microscope 

 stage, using i/42 oil-immersion objective and a 8x Huyghenian 

 ocular, an object that fills the square of the scale is .0125 mm. 

 in diameter; with the Va objective it is .03 mm. in diameter, and 

 with a % objective it is .15 mm. in diameter. Three-fourths 

 of the square equals .0093 mm.; one-fourth of the square is 

 equal to .0031 mm.; one-half of the square is equal to .0062 

 mm. Cell D is in the indirect division process. Cell £7 is a 

 structure that is common among the tumor cells and I have 

 concluded that it is a degeneration result, although it may 

 occur anywhere in the cell nest among the otherwise vigorous 

 cells. It is characterized by a large amount of deeply staining 

 chromatic material, homogeneous and closely massed, having 



