Preface to Second Edition, 



markings of flowers." In using this phrase I was quoting, 

 as I believed, the spirit, not the letter, of Mr. Wallace's 

 teaching in the matter. But since the use of inverted 

 commas made me appear to put into Mr. Wallace's mouth 

 words which he had never used, I have made a slight 

 alteration to correct this mistake. 



In the vexed and much-debated question of the inherit- 

 ance of acquired characters, I still retain and advocate the 

 position of anti-dogmatism. Neither side in this contro- 

 versy will be convinced by a priori arguments. What we 

 need is experimental evidence. In my presidential address 

 to the Bristol Naturalists' Society, on '* The Nature and 

 Origin of Variations," which I hope soon to publish, I have 

 suggested certain experiments on differential use which may 

 perhaps throw light on the question. An interesting work 

 entitled, ** Are the Effects of Use and Disuse Inherited ? " by 

 Mr. Piatt Ball, has appeared since the publication of this 

 volume. In this essay he criticizes Mr. Herbert Spencer's 

 evidence in favour of *' use-inheritance," together with that 

 brought forward by Darwin. Mr. BaU, however, does not, 

 it appears, sufficiently grasp the fact that it is as a source 

 of origin of variations that use-inheritance is operative, if 

 operative at all; and that, if its effects in varieties and 

 species are hidden by the constantly co-operating effects of 

 selection, this does not of itself justify " grave doubts of the 

 alleged inheritance of 'the effects of use and disuse," but 

 rather shows the practical difficulty of proving or dis- 

 proving such use-inheritance by special examples. In 

 science we must not say. Here are the major factors — these 

 practically do all the work ; never mind about the minor 

 factors — the major factors are quite strong enough without 

 them. We must endeavour to study the minor factors or 

 test their existence by the careful elimination of the 

 major factors. 



C. LLOYD MOEGAN. 



Univerbity College, Bristol, 

 July, 1891. 



