are really the only enduring structures ni the nucleus 

 led to their being considered as the probable bcarci-. 

 tary qualities. 



3. The Dynamics ot Nuclear Division. 



Mitotic phenomena in certain plant cell> pie^cnt e\ 

 has very direct bearing on some of the then u s iIk- 

 mechanical and dynamical explanations of luu lear di\ 

 methods of spmdle formation and the various l.)ini> 



caps) which generally in plants seem not t.. be 

 organs of the cells all tend to support Slrasbur^ei > 

 of kinoplasm, which is an outgrowtb and applu atmn 

 Boveri's well known theory of archo])lasm. 



The centrosome theory is supported by ver) Il x 

 tions in Botany, the most notable being that nt Sw 

 for Stypocaulon, who believes that the centrosome • 

 the aster and is maintained as a permanent organ 

 successive cell divisions. Other examples of smiih 

 may be found among the thallophytes which, aft 

 received very little attention, and such types as 

 the diatoms^ offer excellent subjects for ^^'''^"^^^^ 

 series of cell divisions. Hut in contrast to M\i)(Kau 

 be noted that the conspicucms centrospheies ot ui 

 allina disappear with each mitosis to be formed ai 

 same conditions obtain in the germmatmg si)ore> < 

 (Pellia). There seems to be no place tor the o 

 spindle formation as presented in the spore mot ic 

 groups above the thallophytes (see Sec. 11 h- - 

 mitosis in the vegetative tissues of these groups, < 

 as it is by the presence of kinoplasmic caps, coi 

 program of the centrosome theory. 



The morphological manifestations of knioplaHu , 

 that we are driven to a very general concei.Uon <m 

 tion. Kinoplasm runs through cycles m '''^"''^^ 

 passes from a granular condition t.. a fibrillar anc 1 1 



