RELATIONS BETWEEN THE NUCLEUS AND CYTOPLASMA 51 



a time to decompose CO 2 , while in the same way the nucleus and 

 cytoplasm may continue to carry on certain vital actions for some time 

 after they have been separated from one another. 



In all such cases, the observed phenomena result as an after effect 1 

 of the previous conditions, which were such as to permit of the growth 

 and functional activity of the different parts, as well as of the formation 

 of new functional organs. Any such organs formed by secondary 

 differentiation exhibit a more or less marked independence when isolated, 

 and the duration of the activity of which a separated organ is capable is 

 largely or mainly dependent upon external conditions. It is, indeed, not 

 impossible that under special culture conditions, a chloroplast ", or even 

 a nucleus or mass of cytoplasm, might remain living for a very long time, 

 and might possibly be caused to grow and multiply. If it were possible 

 to cultivate isolated organs in appropriate media, we should undoubtedly 

 find that the same general principles previously recognized as controlling 

 the organism as a whole would be equally applicable to its isolated parts. 



As yet, no non-nucleated mass of cytoplasm, nor nucleus free from 

 cytoplasm, has ever been found capable of continued growth and life, 

 however suitable all other conditions might be. In every case the isolated 

 nucleus or mass of cytoplasm dies after a time, though in some cases 

 life is retained and certain vital actions continue to be manifested for 

 a few weeks. 



The cytoplasm may be regarded as living so long as it can be 

 plasmolyzed. and thus continues to exhibit the same diosmotic peculiarities 

 as the living protoplast does. The power of movement may be retained in 

 non-nucleated cytoplasm ; thus, active streaming movements in both higher 

 and lower plants 3 , amoeboid and streaming movement in Amoebae 4 , or a 

 pulsation of the contractile vacuoles of Protista 5 , may still be possible. 



Ciliary movements also continue in the absence of a nucleus, and 

 hence non-nucleated fragments of swarm-spores or Protista may continue to 

 exhibit free swimming movements 6 . The existence of specific peculiarities 



1 It is hence incorrect to suppose that an isolated portion of cytoplasm continues to exist and 

 show functional activity only owing to the after effect of the specific nuclear influences originally 

 acting upon it, for the dependence is a mutual one, and each influences and regulates the other when 

 combined together to form the protoplast. 



[See Ewart, Assim. Inhib., Journal of Linnean Soc., 1895, vol. xxi, p. 424; also Kny, Ber. d. 

 1). Bot. Ges., Sep., 1897; and Ewart, Hot. Centralbl., 1897, Oct.. Bd. LXXII, No. 9.] 



3 Pfeffer, Zur Kenntniss d. Plasmnhaut u. d. Vacuolen, 1890, p. 279; Hauptfleisch, Jahrbuch 

 f. wiss. Bot., 1892, Bd. XXIV, p. 172 ; Gerasimoff, Ueber die kernlosen Zellen bei einigen Conjugaten, 

 1892 u. 1896. On this and other questions, see the reference by Zimmermann, Beiblatter z. But. 

 Centralbl., 1894, Bd. IV, p. Si ; O. Hertwig, Zelle, 1893, p. 264; Verworn, Allgem. Physiologic, 1895. 



4 Hofer, Exp. Unters. lib. d. Einfluss d. Kernes auf d. Protoplastna, 1889, p. 486. 



5 Hofer, I.e. For additional literature, see O. Hertwig and Verworn. 



6 For literature, see O. Hertwig and Verworn. On the cilia of Bacteria, A. Fischer, Jahrb. f. 

 wiss Bot., 1895, Bd. XXVII, p. 153. 



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