46 Mr G. F. Scott Elliot on Recent Researcltes [sess. li. 



the " stabchen " found immediately under the cuticle in the 

 spongy parench}ana cells of the Marattiacea?.* He also points 

 out that all cases of secretions developed immediately beneath 

 the cuticle are not easily brought under Strasburger's theory. 

 These and the other cases mentioned appear to point there- 

 fore towards a power of growth and change possessed in 

 certain cases by this supposed intramural protoplasm. 



But with regard to the inner mechanism of growth neither 

 Strasburger nor Wiesner give a thoroughly satisfactory ex- 

 planation. Strasburger states that it is due to a dissocia- 

 tion of the protoplasm. Wiesner simply states that the 

 dermatosomes take an active part in the growth of the cell- 

 wall,t without saying what that part may be. Now it is 

 probable, as Sti'asburger says, that the mechanism of 

 growth of the starch grain and the cell- wall is the same. The 

 recent researches of Boehm,;j: Schimper,§ and Arthur Meyer || 

 appear to point to the conclusion that starch is deposited 

 from the sugar in solution in the cell when the solution has 

 attained a fixed state of concentration or a certain density, 

 the protoplasm acting as a water-withdrawing substance. 

 Does this occur in the case of the cell-wall ? (Is this 

 what Sachs seems to have thought probable ?)1i 



In su})port, it may be noticed that the formation of cell- 

 wall sometimes coincides very nearly with the disappearance 

 of starch (e.//., endosperm of Ornithogalum,** epidermis of 

 seeds of certain Cruciferai). tt Wiesner also affirms that a 

 sugary substance can be extracted from the cell-wall, as others 

 have also found. The part played by the dermatosomes 

 might be to deposit cellulose from the sugar solution just as 

 a leucoplast deposits starch; but, as stated, Wiesner does not 

 give this or any explanation, and as the explanation probably 

 involves the vital activity of protoplasm, a thoroughly satis- 

 factory one can scarcely be expected. 



The results may l>e sunnned up as follows: — 

 1. Growth of the cell-wall may be effected by deposition 

 IVoiii the ]ii()to])lasm of tlu! cell. 



* Sclieiick, "//cr. dcdcul.,'" Bot. Gen., iii., 1885; .see Bot. Ccntralblatt, xxvi., 

 1886, p. 300. t Wiesner, loc. cit. ; c.f. also Klcbs, loc. cit. 



X lioelmi, Bot. Zcitung, 1883. II Scliiiii[)ur, Bot. Zeilung, 1885. 



§ Arthur Meyer, Bot. Zcitung, 1885. 



H Sach's Textbook, 2ii(l ed. (Euglish), p. 707. 



** Loc. cit.; c.f. also Kleks, loc. cit. 



ft Abraliaiii, Inuug. iJisa. ::u Bonn ; .sec Both Ccnlralb., xxviii. , 1886, p. 1. 



