CELLS IN DIVISION 



two irregular masses not sharply set off from the surrounding 

 karyolymph'. 



Interphase lasts no longer than 27 minutes. In cells with so short a 

 resting period it should readily be possible to determine whether the 

 polarity of chromosomes in prophase is a relic of their previous telo- 

 phase orientation. 



Figure 25 Diagrams of an embryonic neuroblast of Chortophaga 

 viridifasciata during mitosis, a polar and b side view in interphase or 

 prophase c prophase, just before breakdown of nuclear membrane, 

 cell rounding up d Prometaphase e metaphase f mid-anaphase 

 g late anaphase h early telophase j late telophase, the cells have lost 

 their spherical form. (0 and p) polar (e) equatorial cytoplasm. 

 {nc) cytoplasm of nuclear core, (g) ganglion cell, (/j) half spindle, 

 (i) interzonal region, (n) nucleus. From Carlson** {By courtesy, Biol. 



Bull.). 



Vertebrate cells in culture: Amphibia — The original description of 

 Jolly's*'^ method for obtaining dividing erythroblasts free in the blood 

 of the newt was published in 1901. The first paper with Gomandon*^ 

 on the cinematography of such cells in hanging-drop preparations 

 appeared in 1913, but a description of early prophase, based on their 

 final film is not found until the 1934 paper (Comandon et alii^^). In 



77 



