1892.] Phenomena ainl Dere/opment "/Fecundation. 105 



importance in cell division. Since Kobert Brown, in ls:>;>. tirst 

 discovered the cell nucleus in the generative organs of orchids. 

 and Von Mold in l,s:Jo first saw it divide, it has been growing 

 in importance until now. or at least not long ago, the majority of 

 biologists were willing to assign to it all importance in repro- 

 duction and in the life of the cell, the *•» 11 brain as it were. 



Amitoris. — We need only to consider the so called Indirect, 

 mitotic or karyokinetic division. The direct or amitotic nuclear 

 division it appears from FlemmingV late paper and ZieglcrV 

 biological discussion of amitotic unclear division, having merely 

 a nutritive or secretory function, occurs in the animal kingdom 

 only at the end of typical cell multiplication, when the cell is 

 given over to other purposes and loses its power of physi- 

 ological multiplication and reproduction of cells. Amitotic' 

 nuclear division then always indicates the end of the series of 

 divisions. Ziegler thinks "it occurs chiefly (perhaps exclu- 

 sively) in such nuclei as minister to a process of unusually ac- 

 tive secretion or assimilation." In typical gland cells it is 

 frequently found. Whether like conclusion will be reached in 

 the vegetable kingdom is yet doubtful, but in the absence of 

 definite investigations we are justified in assuming that similar 



reproduction we need not further discuss this kind of cell 

 division. 



Karyokenetis — In the cell nucleus, two kinds of protoplasm 

 may be distinguished, the chromatin, so named from its strong 

 affinity for stains, and the achromatin. Other substances 

 have, it is claimed, been differentiated, but these will for the 

 present answer our purpose. Investigators have come almost 

 uniformly to agree that the essential featured of karyokenesis 

 lies in the equal distribution of the chromatin elements to the 

 daughter cells. 



The resting nucleus (fig. 2) presents under the microscope 

 a finely punctate character but close examination will show us 

 that these granules (micros&mata) are connected by fine granu- 



i\V. Flemming, " Ueber Teilung und Kernformen bei Leukocyten und iiber 

 deren Attraktionsspharen." Archiv. f. mikr. Anatomie, 37Bd. 1891. 



2 H. E. Zieeler. " Die biologische Bedeutung der amitotischen (direct) Kern- 

 teitung im Tier?eich." Biol. Centralblatt, Bd. XI, pp. 372-389, July 1891. 



