442 WARREN H. LEWIS 



or until the dye was exhausted from the solution. With the 

 death changes in the cell some alteration apparently took place 

 in the granules and vacuoles and they were unable to retain the 

 dye. Potassium permanganate does not decolorize the neutral 

 red in vitro in Locke's solution. 



DISCUSSION 



Certain reactions are produced by potassium permanganate 

 that seem to have some bearing upon mitosis. The segregation 

 of the chromatin material from the nuclear sap takes place in 

 both mitosis and in the potassium-permanganate experiments, 

 but in the latter the chromatin is clumped. The reduction of 

 the mitochondria to rods and granules occurs in mitosis and 

 also in our experiments. The condensation of the cytoplasm is 

 another peculiar phenomenon common to both mitosis and to 

 the experiments. These reactions suggest that some of the 

 factors involved in mitosis and in potassium-permanganate 

 experiments are alike. Can it be that an increased supply of 

 oxygen is one of the common factors? The evidence is too 

 slight to go into a prolonged discussion. 



The fact that the centrosphere, when present, does not seem 

 to be affected is perhaps more important than appears on first 

 thought. If the centriole and its centrosphere represent the 

 most active or dynamic center of the cell, as is sometimes sup- 

 posed, we should expect it to be involved. In studying cell 

 degeneration^ one is much impressed by the picture of a gradu- 

 ally enlarging centrosphere surrounded by the accumulating 

 granules and vacuoles and the mitochondria. In a former paper^ 

 I expressed the opinion that this seemed to indicate that the 

 centriole or centrosphere was the dynamic center of the cell, as 

 expressed by Boveri years ago. There is, however, another 

 possibility that has gradually been forcing itself into considera- 

 tion, namely, that the centrosphere may have just the opposite 

 significance and is rather to be looked upon as a degenerating 



' Lewis, W. H., 1920 Giant centrospheres in degenerating cells of tissue 

 cultures. Jour. Exper. Med., vol. 31. 



