720 NOTES 



81. Mikosch : Sitzb. Wien, 73, 1876 (cork in bud-scales). 



82. Wiesner : Sitzb. Wien, 79, 1879 (imperviousness of cork to gases). 



83. Extensibility and elasticity of cork. Schwendener : Abh. Akad. Berlin, 1882 

 (p. 39 of the separate). 



84. PheUogen. Sanio : P.J. 2. De Bary : Comp. Anat., p. 109, J. G. Weiss : 

 Denkschr. Regensbg. 6, 1890. Kuhla : Bot. Centr. 71, 1897. Leisering : Ber. 17, 1899. 



85. Light -reflecting plates of Algae. Berthold : P.J. 13, pp. 685 sqq. Hansen : 

 Mitth. Neapel, 11, 1893, Nos. 1 and 2. 



86. De Bary : Comp. Morph. and Biol, of Fungi (sclerotia). 



87. Origin and regeneration of epidermis. Schwarz : Sitzb. Wien. 77, 1878 

 (Monstera). Pfitzer : P.J. 8, pp. 40 sqq. (Peperomia). Vochting : Unters. z. exper- 

 Anat. und Path. d. Pflanzenkorpers, Tubingen, 1908, pp. 73 sqq. (Brassica). 



88. Different botanists have attached and still attach different meanings to 

 the term bast. It has already been explained in the text that, in its original sense, 

 " bast " refers to a single tissue, namely, the extracambial fibrous tissue in the 

 Dicotyledonous stem. Kurt Sprengel, for example, defines the term as follows 

 (Von dem Ban u. der IMatur d. Gewachse, Halle, 1812, p. 423) : " Bast is a whitish 

 tissue, situated beneath the green rind, and distinguished by its fibrous structure 

 and by its great elasticity, toughness and general resistant properties." 



The further development of this primitive conception of bast took place along 

 two divergent fines. A number of notable botanists, such as Link, Kieser and Meyen, 

 continued to associate the term bast with one particular kind of tissue ; the advance 

 of anatomical knowledge forced this school of observers to recognise that bast was 

 not confined to the extracambial region of Dicotyledonous stems, but that a pre- 

 cisely similar tissue also occurred in the axial organs of Monocotyledons. Thus 

 Meyen, in describing the figure of a longitudinal section through the leaf of Scirpus 

 lacustris (Phytotomie, Berlin, 1830), writes as follows : " The wood-bundles (Holz- 

 biindel) are of two kinds, larger ones situated in the middle of the leaf, and smaller 

 ones placed nearer the epidermis ; bast-bundles (Bast -biindel) occur everywhere 

 between the wood- bundles, some lying close beneath the epidermis." Strasburger is 

 therefore mistaken when he alleges (Leitungsbahnen, preface, p. ix) that " the term 

 bast-fibre has always been applied to cells of a particular morphological value and 

 must accordingly be used only in this restricted sense." Similarly, the application 

 of the term bast to mechanically specialised fibres by Schwendener and his school 

 is in no sense an innovation ; all that Schwendener did, in this connection, was to set 

 up a much more exact definition of the term than the earlier botanists were in a 

 position to formulate, the increased precision arising largely as a consequence of 

 the effect upon vegetable anatomy of a physiological mode of treatment. 



The original definition of bast also became modified in a different direction 

 altogether, the term being transferred, without much logical justification, from a 

 particular tissue to a particular tissue-region. Bast, in this purely topographical 

 sense, includes the whole of the extracambial secondary tissues of the Dicotyledonous 

 stem (inclusive of the corresponding portions of the medullary rays), in which bast- 

 fibres in the histological sense occur frequently, though not invariably. It then 

 became necessary to discriminate between hard bast (equivalent to bast-fibres) 

 and soft bast (comprising sieve-tubes and phloem-parenchyma). Later, the term 

 bast was also transferred from the secondary phloem of Dicotyledons and Gymno- 

 sperms to the corresponding portions of the primary vascular tissue, which thus 

 came to be known as bast both in Monocotyledons and in Dicotyledons. 



