OTHER PROTOPLASMIC MOVEMENTS 303 



of nuclear division to a greater or less degree. Thus, when a cell of Spirogyra which 

 normally divides by mitosis is caused to divide amitotically by the action of ether, we 

 have a change similar to the production of Mucor yeast occurring under special 

 conditions \ The shape of other plants is, however, relatively little affected by the 

 external conditions, and hence it is not surprising that in most cases the external 

 conditions exercise little effect upon the character of the mitotic nuclear division. 

 Certain abnormalities may often be produced, however 2 , and in many cases changes 

 in the external or internal conditions may result in one or in numerous amitotic 

 divisions 3 . On the other hand, in the case of many lower organisms in which the 

 nucleus normally divides by amitosis 4 , mitotic nuclear divisions may possibly be 

 produced under special circumstances. In any case transitions occur between typical 

 mitosis and amitosis 5 , and all forms of amitotic nuclear division characterized by the 

 non-production of pronounced mitotic figures do not fall in the two categories pro- 

 posed by Wasielewski 6 . 



Furthermore various instances are known of temporary and reversible differentia- 

 tion in the protoplasm, and in fact the distinction between hyaloplasm and granulo- 

 plasm is one of this character. There is no positive evidence to support Strasburger's 

 use of the terms trophoplasm or alveolarplasm, and kinoplasm or reticuloplasm as 

 indicative of fixed structures 7 . Changes in the relative percentage of each according 

 to the external conditions or the progress of development 8 are quite in accord with 

 a unity of origin for both. Both Hertwig and Zacharias have opposed this doctrine 

 of the existence of permanent organically distinct differentiation in the general 

 cytoplasm. 



The doctrine that continued existence and reproduction is impossible in the 

 absence of mitotic nuclear division is, like the dogma as to the necessity of free 

 oxygen for life, founded upon hasty, incorrect generalization. Nor is there any 

 reason why full hereditary transmission should not be possible unless some of the 

 reproductive living units, biophore, or pangens, group themselves into large visible 

 chromatin-threads. It is quite possible, however, that such grouping previous to 



1 Cf. Pfeffer, Sitzungsb. d. sachs. Ges. d. Wiss., 3. Juli, 1899. 



2 Blazek, Bot. Centralbl., 1902, Bd. XC, p. 548 ; Van Wisselingh, Flora, 1900, p. 373 ; Geras- 

 simoff, Zeitschrift f. allgem. Physiol., 1902, Bd. I, p. 220; Strasburger, Histologische Peitrage, 

 Heft vi, 1900, p. 127. On the lower animals cf. Doflein, Zell- u. Protoplasmastudien, 1900, p. 42 ; 

 E. B. Wilson, Archiv f. Entwickehmgsmechanik, 1901, Bd. xin, p. 389 ; Wasilieff, Biol. Centralbl., 

 1902, Bd. XXII, p. 758; Werner, Bot. Centralbl., 1902, Bd. xc, p. 521; Wallengren, Zeitschr. f. 

 allgem. Physiol., 1902, Bd. I, p. 67. R. Hertwig, Abhandlg. d. Bayr. Akad., 1898, Bd. XIX, p. 687 ; 

 Archiv f. Protistenkunde, 1902, Bd. I, pp. n, 16, gives instances of variations in the nuclear figures 

 at different stages of development. 



3 Wasielewski produced amitosis in roots by the aid of chloral hydrate (Jahrb. f. wiss. Bot., 

 1902, Bd. xxxvin, p. 377). See also Magnus, Jahrb. f. wiss. Bot., 1900, Bd. xxxv, p. 242 ; 

 Chodat, Actes du Congres international de Botanique, Paris, 1900, p. 23; Shibata, Jahrb. f. wiss. 

 Bot., 1902, Bd. XXXVII, p. 648 ; Schimkewitsch, Bot. Centralbl., 1902, Bd. XXII, p. 605. 



4 R. Hertwig, Archiv f. Protistenkunde, 1902, Bd. I, p. 26. 



5 R. Hertwig, I.e., p. 25. 6 L.c., p 401. 



7 Strasburger, Histologische Beitrage, Heft vi, 1900, p. 144. 



8 Strasburger, I.e., p. 144; R. Schrammen, Bot. Centralbl., 1902, Bd. XC, p. 551 ; R. Hertwig, 

 Abhandlg. d. Bayrisch. Akad., 1898, Bd. Xix, p. 690; Zacharias, Flora, 1895, Ergzbd., p. 259. 



