Neogenetic vs. Panmeristic Cell-Division 131 



Went's investigations. 10 Thereby, to my mind is proven 

 the correctness of this conception as opposed to that of 

 neogenesis. Now the situation is reversed. While up 

 to the present time the condition with reference to the 

 nucleus and the chromatophores could be regarded as 

 peculiar, there is now great probability that the different 

 members of a protoplast have the same mode of origin, 

 and therefore that they can claim the rank of independent 

 organs only in so far as they follow this rule. 



Now that the mode of origin for nucleus, trophoplasts 

 and vacuoles has, in the main, been established, and that 

 the works of Wakker 11 have taught us to recognize the 

 crystals, most of the crystalloids, and the aleurone grains 

 as contents of the vacuoles, the problem is chiefly con- 

 cerned with the plasmatic membrane and the granular 

 plasm. 12 In regard to their behavior during cell-forma- 

 tion our knowledge is essentially the same as at the time 

 of Mohl and Hofmeister. Our insight into the pro- 

 cess of cell-division has indeed become deeper, chiefly 

 through Strasburger's work; but the very point in ques- 

 tion, the beginning of the dividing wall, which for some 

 time, seemed to be decided neogenetically, has again be- 

 come extremely uncertain through the discovery (to be 

 discussed later) of the cell-ring by Went 13 as well as 

 through the objections of other investigators. 



10 Went, F. A. F. C. De jongste toestanden der vacuolen. Amster- 

 dam, 1886. Les premiers etats des vacuoles. Arch. Neerl 1887, and 

 Die Vermehrung der normalen Vacuolen durch Theilung. Jahrb. 

 Wiss. Bot. 19: 295. 1888. 



"Wakker, J. H., Studien iiber die Inhaltskorper der Pflanzen- 

 zellen. Jahrb. Wiss. Bot. 19: 423. 1888. Preliminary contributions 

 are found in Maandblad v. Natuurwetensch. 1886, Nr. 7. 1887, Nr. 

 5 and 6, and in Bot. Cent. 33: 360, 361. 1888. 



12 Cf. 6 below, p. 150. 



13 Cf. 7 and 8, pp. 157 and 160. 



