Ncogenctic vs. Panmeristic Cell-Division 129 



size from the beginning, or in cells with many nuclei, first 

 as small formations which increase through growth. 

 Sometimes they contain granules as soon as they become 

 visible, but frequently they occur at first without any inter- 

 nal solid structure, and attain this only later. Every cell- 

 division is usually preceded by a disappearance of the 

 nucleus, which is then followed by the appearance of two 

 or more new nuclei.^ 



The comprehensive investigations of Strasburger and 

 Schmitz have proven this assumption to be erroneous, at 

 first for isolated and then for an increasing number of 

 cases, and wherever a disappearance and subsequent re- 

 appearance of nuclei was assumed, the origination of the 

 new nuclei through division of the original ones could be 

 proven. Exceptions to this rule are no longer known. 



The history is exactly the same for chlorophyll grains. 

 Even in the last edition of his text-book^ Sachs 

 said: "The chlorophyll bodies originate in young cells 

 through the separation of the protoplasm into clearly 

 distinct colorless portions that are becoming green. 

 The process can be conceived to mean that, in the 

 originally homogenous protoplasm, most minute particles 

 of a somewhat different nature are distributed or origi- 

 nate for the first time and then accumulate at various 

 points, appearing as differentiated bodies.'* That the 

 green bodies which had formed in this way could multi- 

 ply through division, and that the chlorophyll bodies of 

 many algae are usually cut through at every cell-division 

 by the forming wall, can easily be observed and was not 

 unknown at that time. 



But it was Schmitz who first showed that, in the algae. 



^Hofmeister, Die Lehrc von der PflanzenijcUe. p. 79. 1887. 

 ^Lehrbuch der Botanik. 4. Auflage, p. 46. 1874. 



