( xcix ) 



ago the original paper, I could not avoid thinking that some 

 special explanation would hereafter be found for so curious a 

 case. I speculated whether a species very liable to repeated 

 and great changes of conditions might not assume a fluctuating 

 condition ready to be adapted to either conditions." * 



I venture to express the prediction tliat this class of cases, 

 already very numerous, will hereafter be immensely enlarged, 

 and will become especially important in the vegetable king- 

 dom. t Although Hooker at one time took the opposite side, 

 and thought that plants were never "changed materially by 

 external conditions — except in such a coarse way as stunting 

 or enlarging," J Darwin considered that " physical conditions 

 have a more direct effect on plants than on animals." § Un- 

 doubtedly the view at the time was that of Buffon, the idea of 

 an operation of the environing forces almost as direct as 

 those which produce the weathering of rocks or the whitening 

 of an exposed flint. But it is probable that the more in- 

 timately we know of the conditions of plant-life, the more 

 fully it will be recognised that all such changes are adaptive. 



* " More Letters," vol. i, p. 391, Letter 303. 



t See " StimiThi.s ajid Mecbanisin as Factors in Organisation'' by J. 

 Bretland Farmer, F.R.S. (the New Phytologist, vol. ii, Nos. 9 and 10, 

 Nov. and Dec. 1903). Professor Farmer speaks of the probable prevalence 

 in the plant -world of "a constant specific mechanism that is able to be 

 actuated in different ways by different kinds of stimuli." Although for 

 the purpose of his paper Professor Farmer is concerned with the train of 

 physico-chemical sequences which is set going, utility or no utility, when- 

 ever the mechanism of an individual is stimulated, he fully admits that 

 the mechanism i'^self has come to be a character of the species by the oper- 

 ation of natural selection. "Naturally," he says, "only those sjiecies 

 whose inner character expressed itself in making these 'suitable' adjust- 

 ments to the environment were able to survive. " 



Toward the close of his paper Professor Farmer seems to bring the con- 

 siderations that have regard to the species into somewhat unnecessary 

 conflict with those that have regard to the individual. Thus he says 

 that "current literature still teems with teleo'ogical explanations that 

 really explain nothing, but rather bar the way of scientific enquiry." 



A properly loaded, well-constructed modern gun goes otf, for disadvan- 

 tage no less than for advantage, wlieu its trigger is pulled ; but the very 

 existence of the gun depends upon a long succession of past stages, e ich of 

 which was more advantageous than its predecessor. The recognition of 

 this history does not bar the way of enquiry, but rather stimulators and 

 suggests a searching and intelligent study of the latest mechanism with 

 all its intricacy. 



X See the letter from Hooker to Darwin, March 17, 1862, in " More 

 Letters," vol. i, p. 197. 



§ See the letter from Darwin to Lyell [June 14, 1860], " Life and 

 Letters," vol. ii, p. 319. 



