A COUNTER CRITICISM. 151 



ted factor ; and it is surprising that this assumption should have 

 been made after reading the second of the two articles criticised, 

 in which this factor omitted from the first is dealt with ; this 

 omitted third factor being the direct physico-chemical action of 

 the medium on the organism. Such a thought as that which the 

 Duke of Argyll ascribes to me, is so incongruous with the be- 

 liefs I have in many places expressed that the ascription of it 

 never occurred to me as possible. 



Lower down on the same page are some other sentences hav- 

 ing personal implications, which I must dispose of before going 

 into the general question. The Duke says " it is more than doubt- 

 ful whether any value attaches to the new factor with which he 

 [I] desires to supplement it " [natural selection] ; and he thinks 

 it " unaccountable " that I " should make so great a fuss about 

 so small a matter as the effect of use and disuse of particular 

 organs as a separate and a newly recognised factor in the devel- 

 opment of varieties." I do not suppose that the Duke of Argyll 

 intended to cast upon me the disagreeable imputation, that I 

 claim as new that which all who are even slightly acquainted 

 with the facts know to be anything rather than new. But his 

 words certainly do this. How he should have thus written in 

 spite of the extensive knowledge of the matter which he evi- 

 dently has, and how he should have thus written in presence of 

 the evidence contained in the articles he criticises, I cannot un- 

 derstand. Naturalists, and multitudes besides naturalists, know 

 that the hypothesis which I am represented as putting forward 

 as new is much older than the hypothesis of natural selection — 

 goes back at least as far as Dr. Erasmus Darwin. My purpose 

 was to bring into the foreground again a factor which has, I 

 think, been of late years improperly ignored ; to show that Mr. 

 Darwin recognised this factor in an increasing degree as he 

 grew older (by showing which I should have thought I suffi- 

 ciently excluded the supposition that I brought it forward as 

 new) ; to give further evidence that this factor is in operation ; 

 to show there are numerous phenomena which cannot be inter- 

 preted without it ; and to argue that if proved operative in any 

 cases, it may be inferred that it is operative on all structures 

 having active functions. 



Strangely enough, this passage in which I am represented as 

 implying novelty in a doctrine which I have merely sought to 

 emphasise and extend, is immediately succeeded by a passage in 

 which the Duke of Argyll himself represents the doctrine as be- 

 ing familiar and well established : 



That organs thus enfeebled [i. e. by persistent disuse] are transmitted by in- 

 heritance to offspring in a like condition of functional and structural decline, is 

 a correlated physiological doctrine not generally disputed. The converse case — 



