4l6 LAMARCK, HIS LIFE AND WORK 



tantin, Bonnier, and others, all demonstrating that 

 the environment acts directly on the plant. 



Henslow also suggests that endogens have origi- 

 nated from exogenous plants through self-adaptation 

 to an aquatic habit,* which is in line with our idea 

 that certain classes of animals have diverged from the 

 more primitive ones by change of habit, although this 

 has led to the development of new class-characteris- 

 tics by use and disuse, phenomena which naturally do 

 not operate in plants, owing to their fixed conditions. 



Other botanists — French, German, and English — 

 have also been led to believe in the direct influence 

 of the milieu, or environment. Such are Viet,f and 

 Scott Elliot, :j: who attributes the growth of bulbs to 

 the " direct influence of the climate." 



In a recent work Costantin§ shares the belief em- 

 phatically held by some German botanists in the 

 direct influence of the environment not only as modi- 

 fying the form, but also as impressing, without the 

 aid of natural selection, that form on the species or 

 part of its inherited stock; and one chapter is de- 

 voted to an attempt to establish the thesis that 

 acquired characters are inherited. 



* " A Theoretical Origin of Endogens from Exogens through 

 Self-Adaptation to an Aquatic Habit," Linnean Society Journal : 

 Botany, i8g2, /. c, xxix., pp. 485-528. A case analogous to kineto- 

 genesis in animals is his statement based on mathematical calcula- 

 tions by Mr. Hiern, "that the best form of the margin of floating 

 leaves for resisting the strains due to running water is circular, or at 

 least the several portions of the margin would be circular arcs " (p. 

 517)- 



f_"De I'lnfluence du Milieu sur la Structure anatopiique des 

 Vegetaux," Ann. Sci. Nat. Bot., ser. 6, xii., 1881, p. 167. 



i " Notes on the Regional Distribution of the Cape Flora," Trans- 

 actions Botanical Society, Edinburgh, 1891, p. 241. 



S^Les Vigdtaux et les Milieux cosmiques , Paris, 1898, pp. 292. 



