NOTES 721 



There can be little doubt as to which of these modifications <>(' the original 

 significance of the term " bast " is the more precise and logical. 



89. Histology of bast-fibres. Schwendener : Das mechanische Prinzip, 1874, 

 pp. 3 sqq. De Bary : Comp. Anat. Wiesner : Mikroskopische Unters. pp. 21 sqq, 

 Id. Rohstoffe d. Pflanzenreichs, Leipzig, 1912 (2nd ed.) Ch. XVIII. Von Hohnel : 

 Uber pflanzliche Faserstoffe, Vienna, 1884. Id. Mikroskopie d. technisch-verwen- 

 deten Faserstoffe, Vienna, 1887. Krabbe : P.J. 18. The distortions exhibited by 

 certain bast-fibres, described by Von Hohnel (P.J. 15, p. 311), are attributed by 

 Schwendener (Ber. 12, pp. 239 sqq.) to the effects of preparation, a view which is 

 shared by Wiesner. 



90. Nageli : Theorie d. Gahrung, Munich, 1879 (micellar structure of bast-fibres). 



91. CoUenchyma, Schwendener : I.e. [89], pp. 3 sqq. De Bary : Comp. Anat. 

 Ambronn : P.J. 12, 1881. Giltay : Arch, neerl. 17, 1883. Van Wisselingh : ibid. 

 Carl Miiller : Ber. 8, 1890. Jonas Cohn : P.J. 24. 



Bokorny's interpretation of collenchyma as a water-conducting tissue, and 

 C. Midler's views regarding the water-storing capacity of this tissue have already 

 been disposed of by Strasburger (Leitungsbahnen, pp. 557 sqq.) and J. Cohn (I.e.). 

 There was therefore no need to refer to those theories in the text. 



92. Although sclereides and genuine fibres are connected by intermediate forms, 

 these are not so numerous as to justify us in placing two such very different cell- 

 types in a common category under the name of sclerenchyma. Where this is done 

 (cf. Sachs, De Bary, etc.), the only distinguishing feature of a sclerenchyma-element 

 is the thickness of its walls, a characteristic which is not only wanting in definiteness, 

 but is also not directly connected with the mechanical function. Apart from their 

 thick- walled character, however, there is little in common between bast-fibres and 

 sclereides. Wiesner takes up the same attitude in his Elementen d. Anatomie u. 

 Physiologie d. Pflanzen (Vienna, 1881). where he writes (p. 162): "Their unusual 

 inextensibility and tensile strength, their flexibility, the uncoloured and altogether 

 relatively unmodified condition of their cell-walls, which usually exhibit the re- 

 actions of pure cellulose all these are features, in respect of which bast-fibres 

 offer a very marked contrast to the hard, brittle, lignified, brown or yellow 

 sclereides." The difference between the two types of cell could not be expressed 

 in clearer language. 



Concerning sclerenchyma (in the narrow sense) cf. De Bary : Comp. Anat. 

 Tschirch : P.J. 16, pp. 30 sqq. Id. Angewandte Pflanzenanatomie, Vienna and 

 Leipzig, 1889, pp. 300 sqq. Potonie : Kosmos, 8, pp. 33 sqq. G. Haberlandt: Sitzb. 

 Wien, 75,1877 (testa of Phaseolus). Ibid. Mitth. Steiermk. 1887 (Begonia). Solereder: 

 I.e. [47]. With regard to the filling in of the ruptured fibrous cylinder with 

 sclerenchyma. see : Tschirch: I.e. [92]. Schwabach : Bot. Centr. 76, 1898. Devaux: 

 Mem. Bord.,ser. V., 5, 1899. Schellenberg : Schwendener-Festschrift, 1899. Vochting: 

 P.J. 34, 1899. Kny : P.J. 37, 1901. Gaedecke : Das Fiillgewebe d. mechanischen 

 Ringes (Inaug.-Dissert.), Berlin, 1907. 



Strasburger maintains (Leitungsbahnen, p. 77) that the sclereides which occur 

 in the bark of the Larch, Spruce and Fir, and in the flesh of the Pear, have no 

 mechanical significance at all ; he believes that metabolic processes which go on in 

 the starch-conducting tissues of the plants in question lead to the production of 

 superfluous cellulose- material, which is then deposited in the form of secondary 

 thickening layers on the walls of the sclereides. It seems, however, very unlikely 

 that cellulose, which is ordinarily a plastic substance, should ever appear as a useless 

 by-product of metabolism ; nor is there any good reason for supposing that trans- 

 location of carbohydrates involves the production and deposition of cellulose. 



2 z 



