Germ Cells of Leptinotarsa Signaticollis. 163 



nuclei." The passage of the nuclear material into the cytoplasm 

 is regarded as a fundamentally important condition to the sub- 

 sequent changes undergone b}^ the latter. 



Wilson and Mathews ('95) have shown that by far the greater 

 part of the chromatin is set free in the cytoplasm in the first 

 maturation division of the starfish egg, and F. R. Lillie ('06) 

 states that in Chcetopterus the greater part of the germinal vesicle 

 consists of a ^'residual substance" which is set free in the cyto- 

 plasm of the first maturation division, and plays an important 

 part in the future development. 



If these phenomena are characteristic for mitosis in general, as 

 they seem to be, the rupture of the nuclear membrane permits the 

 escape of some substance into the cytoplasm that is essential to the 

 changes which follow. Therefore, if the membrane remains intact 

 during division, a difference in cell metabolism is certain to take 

 place. 



Lyon ('04) has shown that the production of carbon dioxide by 

 the dividing egg follows a rythm parallel with that of the nuclear 

 division, and Loeb ('06) has connected these oxidations with the 

 synthesis of nucleins from the compounds of cell metabolism — a 

 process which likewise undergoes a rythm parallel with that of 

 the mitotic process. 



Mathews ('07) suggests that the periodic dissolution of the nu- 

 clear membrane in mitotic cell division might have the signifi- 

 cance of providing for the distribution of the oxydases (synthesized 

 in the nucleus) through the cytoplasmic area which would natur- 

 ally result in a periodic acceleration of oxydative processes in the 

 cell. 



R. S. Lillie ('08) points out that as certain enzymes exhibit the 

 properties of nucleoproteins, it is reasonable to regard the so-called 

 ''oxy chromatin" or "residual substance" as consisting, at least 

 in part, of ferments concerned in the chemical processes — largely 

 oxidative in nature as shown by the condition in the starfish egg — 

 that determine the later characteristic changes in the cytoplasm. 

 In this way the physiological data can be readily reconciled with 

 cytological observations. 



The failure of the nuclear membrane to dissolve in the course 



