44 Mr G. F. Scott Elliot on Recent Researches [sess. li. 



gyra one can see a ring of cell-wall projecting into the cell, 

 and the edges connected by two parallel rows of granules 

 embedded in a protoplasm plate (probably a network) ; cf. 

 Schmitz * and Strasburger,t who appear to have also seen 

 this. Moreover, the layer of protoplasm in contact with the 

 cell-wall, and undergoing change into cellulose, is perfectly 

 well known {cf. Pfurtschneller).| A reaction is given by 

 Schmitz for this " innen haut." It consists in leaving the 

 material twenty-four hours in picric acid, then washing and 

 staining in hai-matoxylin, which colours the granules or 

 microsomes \dolet. The process of conversion of this layer 

 of protoplasm into cell-wall was traced so long ago as 1855 

 by Crliger § in the cells of the aerial root of an orchid. These 

 cells possess a peculiar spiral marking, and Criiger was able 

 to see currents of protoplasm accompanying these spiral 

 bands before they were fully formed (confirmed by Dippel,|| 

 Schmitz, and Strasburger). Strasbuiger gives similar in- 

 stances, e.g., spiral vessels of Impatiens and Bryony,1[ also 

 the spiral bands on Sphagnum leaf, &c. In certain cases he 

 was able to contract the protoplasm away from the cell- 

 wall, but not all of it, for some of the microsomes, coloured 

 l)y lueniatoxylin, were observed sticking in the cell-wall, 

 while most of the protoplasm was lying in the centre of the 

 cell. A conclusive proof that the protoplasm of the cell 

 itself can continually change part of itself into cell-wall is 

 afforded by an experiment of Klebs.** He placed (Edogonium 

 filaments in a 10 j^er cent, solution of glucose, and found 

 that the pnjtoplasm, though contracted entirely away from 

 the cell-wall, had, after a certain time, formed a new cellulose 

 coat, distinct and separate fi'oni the older one, round itself. 

 Thus in most cases it appears probable that the protoplasm, 

 assumed on Wiesner's theory to exist within the cell-wall, 

 does not assist in the growtli in thickness of the wall. 



There are, however, certain cases in which a cell-wall 

 exhibits growth of itself. For example, a certain turgidity 

 resulting from hydrostatic pressure within the cell is necessary 



* Loc. c'U. t Loc. cit., pp. 83, 173. 



X Pfurt.sclinell(;r, Bot. Centralllult, xxii., 1885, p. 13. 



§ Criiger, Bot. Zeitung, 1855, p. 606. 



11 Dippel, ALU. d. Nutur. Ocs. zu Halle, Bd. x., 1867; see Stra.sburger, loc. 

 cit., p. 78; Schmitz, loc. cit. 



1 Cf. also Giltay, Bd. xxii. Bot. Centralblult, 1885. 



** Botanisr.lic CentrulhlaU, xxviii., 1886, ]). 156. 



