212 KANSAS UNIVERSITY SCIENCE BULLETIN. 



this material and which are plainly cells in varying degrees of 

 degeneration, as evidenced by changes in the chromatin, cy- 

 toplasm and cell wall, and note if there is any similarity be- 

 tween them. 



Figures 5, 6, 7 and 8 are used to further illustrate these three 

 cell changes as they appear in various parts of the tumor. In 

 these drawings I omitted the greater number of the resting 

 cells. 



I will supplement this preliminary account by short de- 

 scriptions of individual cells in the several plates with inter- 

 pretations of their variation from the normal. 



I have used the term "cell nests" to mean the group of cells 

 within the alveoli; the term "chromatic cells" to mean those 

 cells in that condition in the degeneration process just before 

 the chromatin loses its staining power and when it has swollen 

 so much and become so diffuse as to fill the entire nucleus as 

 a more or less densely staining mass. 



OBSERVATIONS. 

 The Cells of the Nests Change by Mitosis, Amitosis and Degeneration. 



In showing the cell changes of these nests I will simply use 

 a number of figures, describing each one with some amount of 

 detail and inserting comments as observations suggest. 



Figure 1 is drawn from cell nest 2. It includes three cells 

 dividing directly, one dividing indirectly, two cells in the 

 process of degeneration, and a number of resting cells. 



The resting cell is smaller than the dividing cell, is of poly- 

 hedral shape, has a limiting membrane, and a large, well- 

 marked nucleus. Its cytoplasm is denser than the karyoplasm 

 and is of a reticular appearance. The nucleus has a well- 

 marked nuclear wall and usually contains from one to three 

 regularly round, deeply-stained chromatic bodies which I will 

 call chromatin nucleoli. A directly dividing cell is of much 

 larger size than the resting cell and usually a bit clearer, a 

 condition suggesting that it has included a large amount of 

 fluid preparatory to its division. The nucleus divides by the 

 formation of a groove or cleft on one side. I have not seen a 

 cell where the cleft appeared on the two sides. The cleft 

 deepens and the nuclear substance pulls apart to form the 

 regular outline of the daughter nuclei. The nuclear membrane 

 seems to follow the deepening cleft so that as soon as the seg- 

 ments have separated the karyoplasm is enclosed by its wall. 



