CH. XI] B. MORPHOLOGICAL 105 



with a bi-ternate leaf, grows in alpine bogs, T. minus, with a 

 tri-pinnate leaf, in chalky pastures, and T. flavum, with a bi- 

 pinnate leaf, on river banks. In the next genus, Anemone, A. 

 Pulsatilla, with a bi-pinnate leaf, grows in chalky places, and A. 

 nemorosa, with a ternate leaf, in woods. Yet these two genera are 

 closelv related, and surelv. if the structural forms of the leaves 

 had anything to do with the conditions, the two with the bi- 

 pinnate leaves would occupy places not very dissimilar. The usual 

 reply of the selectionists to questions like this, that at some time 

 there must have been such conditional differences that a dif- 

 ference like that between these various types of leaf had a 

 physiological significance, is simply an appeal to ignorance, for 

 which there is not the slightest evidence. 



If one takes the matter the other way round, one gets a good 

 argument against this contention of theirs. Why does one find 

 pinnate leaves, to take just a few examples from the British flora, 

 in Clematis, climbing in hedges, in Nasturtium in wet places, in 

 Cardamine in meadows, Anthyllis in dry pastures, Vicia climbing 

 in waste places, Sjnraea on downs, Potentilla by the roadside, 

 Rosa in hedges, Myriophyllum in water, and so on; and why in 

 Geum urbanum are the pinnate leaves only the lower, radical, 

 leaves of the plant? The argument of the selectionists is clearly 

 an admission of the point for which I am contending, that adapta- 

 tion is mainly an internal, physiological, or functional process, 

 without any necessary influence upon the outer, structural 

 features of the plants concerned. 



The Englishman is successful enough in the conditions that 

 obtain in England, but if taken directly to India, and asked to 

 make good in the conditions to which the natives of that country 

 are subject, he would fail, primarily on account of the very 

 different climate. But he might succeed, if he were adapted by 

 nature's method of extremely slow change, say in a quarter or 

 half a million years. But by quick change he would be like the 

 potato and the dahlia, which have not yet become acclimatised 

 to Europe. Time is the needful thing in acclimatisation and 

 adaptation, and nature has plenty of it available. But it is of 

 course by no means unlikely that so great a change would be 

 beyond the limits of the Englishman's possible adaptation; there 

 are many cases in plants which seem to point to the existence of 

 such a limit. From what we know of man, it is not to be expected 

 that in the course of this adaptation the Englishman would suffer 

 great morphological changes, though he might acquire a darker 



