206 Pangens in the Nucleus and Cytoplasm 



examined with this point in view.^ In the Botanische 

 Zeitung for 1885, I have furnished proof that mechanical 

 contrivances are not sufficient for the transmission of the 

 assimilated nutrient matter in plants, and that, of the 

 processes known up to date, it can only be accomplished 

 by the currents of the protoplasm.^ 



In this connection I have carefully verified Velten's 

 statement, and have confirmed the quite common exist- 

 ence of currents in vigorously living plants/*^ 



The mechanical possibility of a transmission of pan- 

 gens is, therefore, sufficiently assured for all plant-cells. 

 Only one difficulty has yet to be overcome. Following 

 the precedence of Hofmeister, it was generally assumed 

 that the currents in the cells begin only at the end of the 

 meristematic period, and that, until that time, the granu- 

 lar plasm is in a state of rest. Now the meristematic 

 period is not only that in which the cells originate, but 

 also that in which their later character is chiefly deter- 

 mined. Hence it is in this very period that we must place 

 the most important part of the transportation of the 

 pangens. 



But Hofmeister's statement was based on insufficient 

 observations. A subsequent investigation by Went, with 

 the more modern methods, led to a quite different result." 

 The movements are indeed slow, and one examination 

 will often not disclose them. But if the observation of 



^Velten, W. Ueber die Verbreitung der Protoplasmabewegungen 

 im Pflanzenreiche. Bot Zeit. 30: 645. 1872. 



^Vries, H. de. Ueber die Bedeutung der Circulation und do 

 Rotation des Protoplasma fiir den Stofftransport in der Pflanze. Bo 

 Zeit. 43: 1. 1885. 



i^Over het algemeen voorkomen van circulatie en rotatie ii 



de weepelcellen der planten, Maandhl. v. Natuurw. No. 6. 1884. 



Cf. ihid. No. 4, 1886, and Bot. Zeit. 43: 1, 17. 1885. 



"Went, F. A. F. C. Die Vermehrung der Normalen Vacuolen 



durch Theilung. Jahrh. Wiss. Bot. 19: 329. 1888. 



