710 NOTES 



Winterstein : Ber. L895. pp. 65 sqq. (Fungus-cellulose). Schellenberg : P.J. 29, 1896 

 (iignified wails). Czapek : Hoppe-Seyler's Zeitschr. 27, 1899 (lignin-reaction). Id. 

 Flora. 18!)!) (cell-walls of Mosses and Liverworts). Id. Biochemie, 1, pp. 506 sqq. 

 Euler : Grundlagen u. Ergebnisse d. Pflanzen-chemie, Braunschweig, 1908, Vol. I. 



21. Active growth of a cell-wall might take place in one of two different ways. 

 In the first place, the growing membrane may be possessed of a definite molecular 



or micellar structure, which may be termed the "living structure" of the wall. 

 Nageli distinguished three different conditions of the cell-wall in respect of its 

 micellar structure, namely, "life," ''natural death" and "imbibition." The 

 " living" condition is characterised by the fact that the membrane is capable of 

 independent growth by intussusception : in these circumstances, the underlying 

 protoplasm merely keeps the membrane supplied with soluble plastic material. 

 Under certain conditions, therefore, such a "living" cell-membrane should be able to 

 go on growing, even though it is not in actual contact with living protoplasm, pro- 

 vided it is sufficiently supplied with soluble plastic compounds. Fitting (B.Z. 1900* 

 alleges that this case is exemplified by the developing spore-wall in Isoetes and 

 Selaginella. 



The " living " state of the cell-wall, with which its power of active growth is 

 correlated, might, on the other hand, depend upon the presence in the cell-wall of 

 protoplasm continuous with the living contents of the cell. This view has found a 

 strong adherent in Wiesner. There is undoubtedly much to be said in its favour. 

 It dispenses with the necessity of assuming a mysterious " living " condition of 

 the cell-wall, independent of the presence of protoplasm ; and thus maintains the 

 fundamental physiological principle which regards the protoplasm as the sole living 

 constituent of the cell. It is true that Wiesner does not explicitly state that the 

 " membrane-plasma " is a part of the protoplast, but his remarks must undoubtedly 

 be interpreted in this sense. As Correns has pointed out, the chief objection to 

 Wiesner's theory is the lack of any proof that cell-membranes ever contain proto- 

 plasm ; in fact, Klebs, Fischer and Correns go so far as to deny the presence of 

 protein-Compounds as alleged by Wiesner and Krasser in cell-walls. Cf. Note 

 18 (Wiesner, Krasser, Klebs and Correns) ; also Strasburger : Hist. Beitr. 2, 1889, 

 and Reinhardt : Festschr. f. Schwendener, Berlin, 1899 (plasmolytic method). 



22. Sachs : Flora, 189.3. Amelung : Flora, 1893. 



23. Nageli : Mechanisch-physiologische Theorie d. Abstammungslehre, 1881, pp. 

 357 sqq. 



21. Sachs : Sitzb. Wiirzb. 1878 (Nov.). 



[24 a. The term " non-cellular," due to Sachs, is now chiefly of historic interest. 

 In English botanical literature multinucleate "cells " are generally termed 

 " coenocytes." ] 



25. Janse : P.J. 21, 1890, pp. 269 sqq. 



26. The exceedingly voluminous literature of nuclear and cell-division cannot 

 be considered in detail here. On the botanical side, special attention may be drawn 

 to the work of Strasburger and his school (Strasburger : Hist. Beitr., P.J. 30, 1897, 

 etc.), and to several papers by Nemec. Cf. also Hacker : I.e. [10]. 



27. Warburg (B.Z. 1885, p. 29) maintains that " logically, one ought to distinguish 

 several protective dermal systems, each corresponding to a different principal 

 function of the dermal tissue ; the most important of these would be concerned with 

 the reduction of transpiration, the others with the restriction of radiation, protection 



