NATURAL SELECTION. 



117 



the self -same flank, with self -same aspect, we may and do find extra 

 foliose varieties, dwarfed varieties, crested varieties, and depauperate 

 varieties. We find these intricately intermingled with the normals and 

 have usually to dig up a clump and sort the "find " out of the tangle. 

 Hundreds of distinct varieties have been found under such circumstances, 

 and exist in proof at any rate of their discovery. How is it possible, then, 

 I ask, to reconcile such facts with Professor Henslow's theory that 

 variation only occurs when a change of environment takes place, and then 

 only varies to fit the altered conditions ? 



The conditions obviously have not altered, and the divergent forms of 

 variation prove that they have not varied in sympathy with any 

 recognisable factor. Moreover, why is it the rule that such plants are 

 either solitary or few in number and closely associated ? Why did their 

 normal relatives mingling with their rcots and fronds not respond too if 

 any environmental influence were at work ? 



Finally in No. 7 Professor Henslow implies that a seedling may and 

 does begin normally, and subsequently adopts the new characters in 

 sympathy with the environmental impulse. I have never seen a case of 

 this sort ; the varietal character of a fern is usually shown by an unusual 

 shape of the primary frond, leading me to believe that the varietal 

 tendency is already in the spore when shed. 



It seems to me that Professor Henslow confounds the difference of 

 form assumed by wild plants (let us say the cabbage) when brought 

 under culture with variation proper. The cabbage is obviously a highly 

 variable plant, but it must not be forgotten that under cultivation it is 

 always under the eye of a searcher for varieties, and it is due to this fact 

 and the immense numbers raised annually many of them on lines of 

 definite selection for improvement and enhancement of type that we have 

 such a multitude of different forms of it. That these forms are responsive 

 to environment is beyond proof ; their extra size and vigour undoubtedly 

 are obvious enough and plainly due to high culture ; but that is all that is 

 demonstrable. Take a wild cabbage and " fatten " it up by high culture, 

 and having done so plant it out on its native cliff ; and if it survive it 

 will resume its old wild form. Not so a " sport," and that is the vital 

 difference. 



In view of the above, and much more that I could add, I fail to believe 

 that Professor Henslow will do much to detract from the world's estimate 

 of Darwin's " unproven hypothesis" unless he can adduce at least an 

 instalment of that " infinite amount of actual proof " which he alleges to 

 exist to the contrary, and ceases to put forward as such the cases with 

 which I have dealt. 



Since writing the above I have heard Professor Henslow's lecture at 

 the R.H.S. Hall on March 5 on the True Darwinism, which has given me, 

 I think, a clue to the conflict between the facts I have cited and Professor 

 Henslow's statements. With the exception of a passing allusion to Pro- 

 fessor De Vries's experiments with (Enothera there was not the slightest 

 reference to true variations, i.e. inheritable differentiations of plan. The 

 whole of the pictures and dried specimens dealing with variation as 

 shown by him exemplified merely the fact that, by high culture and feeding, 

 plants can be induced to assume robuster forms, and that the seed may 



