[339] 'Bot. Zeit.,' 1850, t. viii, pp. 514, 664. 'Flora,' (B. Z.) 1832, t. xv, p. 252; also cited in 'Ann. des Serres et des jardins,' vi, pp. 241-5. See also Schlechtendal, 'Bot. Zeit.,' 1845, t. 3, p. 6. [340] 'Bull. Soc. Bot. France,' t. viii, p. 453. [341] See also Allmann, 'Rep. Brit. Assoc.,' July, 1851. [342] 'Theory of Horticulture,' ed. 2, p. 82. [343] 'Mem. Soc. Hist. Nat. Paris.' i, 16. [344] Gen. Munro, 'Trans. Linn. Soc.,' xxvii, p. 7. [345] 'Bull. Soc. Bot. Fr.,' 1857, p. 21. [346] 'Ann. Scienc. Nat.,' t. viii, 1837, p. 50, and 'Bot. Zeit.' (R.), 1836, t. xix, p. 513, &c. See also MM. Sourd Dussiples and G. Bergeron, 'Bull. Soc. Bot. France,' viii, p. 349; Von Schmidel, 'Icon. plant. et Anal. part.' 1782, p. 210, fig. 54. [347] Godron, 'Bull. Soc. Bot. Fr.,' xiii, p. 82, Rev. Bibl. [348] Cited in Henfrey, 'Bot. Gazette,' iii, p. 12. [349] 'Ann. Nat. Hist.,' September, 1856, p. 56. See also Kirschleger, 'Flora (Bot. Zeit.),' xxiv, 1841, p. 340, _Salix alba_. Henschel, 'Flora (Bot. Zeit.),' 1832, t. xv, p. 253, _S. cinerea_. Hartmann, 'Flora (Bot. Zeit.),' xxiv, p. 199, _S. nigricans_. Meyer, C. A., 'Bull. Phys. Math.,' t. x, _S. alba_. PART IV. HETEROMORPHY. There are certain malformations that have little in common beyond this, that they cannot readily be allocated in either of the great groups proposed by writers on teratology. There are also deformities which, unlike the majority of deviations from the ordinary structure, are absolute and not relative. While the latter are due to an exaggeration, or to an imperfection of development, or, it may be, to a partial perversion in organization, the former differ from the normal standard, not merely in degree, but absolutely. This is often the case when disease or injury affects the plant; for instance, in the case of galls arising from insect-puncture the structure is rather a new growth altogether, than dependent on mere hypertrophy of the original tissues. These absolute deformities arising from the causes just mentioned belong rather to pathology than to teratology strictly so called; but, under the head of deformities, may be mentioned sundry deviations not elsewhere alluded to. CHAPTER I. DEFORMITIES. The special meaning here attached to the term deformity is sufficiently explained in the preceding paragraph; it remains to give a few illustrations, and to refer to other headings, such as Heterotaxy, Hypertrophy, Atrophy, &c., for malformations capable of more rigid classification than those here alluded to. [Illustration: FIG. 166.--Portion of the under surface of a cabbage-leaf, with horn-like excrescences projecting from it.]