THE TRANSMUTATION OF CHARACTERS 19 



35. Most biologists now reject this, the Lamarckian hypothesis, 

 on the ground that it is against the weight of evidence. It is not 

 realized, however, that here we have a question not of the trans- 

 mission but of the transmutation of characters ; for the child is not 

 supposed to reproduce that which the parent developed (an effect 

 of use or injury), but something vastly different (a response to the 

 stimulus of nutriment). As a fact the evidence against the 

 Lamarckian hypothesis is very conclusive. Characters which 

 evolution has fitted parents to develop under the stimulus of use 

 and injury do not tend to be automatically transmuted in the 

 offspring into characters which develop under the stimulus of 

 nutriment. Such a change would be as intrinsically improbable 

 as a change of eyes into ears. But the language used has raised 

 a false issue, has diverted attention from the real significance of 

 responses to use and injury, and of the evolution which enables the 

 individual to develop them. The belief, reached after long and 

 heated controversy, that * acquirements ' are not ' inherited/ has 

 caused nearly all students of heredity to think of them as mere 

 accidents which have no importance except in so far as they 

 obscure the outlook and render the discovery of the truth difficult. 

 Hence, for example, the notion that the acquirements of the 

 blacksmith which comprise among other things almost his entire 

 muscular development since infancy are limited to the extra 

 development which results from the nature of his labour. We 

 shall see how mistaken is this view, and how great a gap in bio- 

 logical thought and study has resulted in consequence. In effect 

 it has shorn the study of heredity and evolution not only of one of 

 its most important branches, but of its main title to practical 

 utility as well. 1 



36. Nevertheless, since these terms, innate, acquired, and inherit- 

 able are firmly established in the literature of heredity, their use 

 is now in many ways convenient. For the sake of clear thinking 

 it is necessary, however, to bear their real meanings carefully in 

 mind to remember always, when speaking of multicellular organ- 

 isms, that by an inborn character is meant one which develops 

 under the stimulus of nutriment, by an acquirement one which 

 develops under the stimulus of use or injury, and by inheritance 

 the reproduction, as a nutritional character, by the child of a 

 parental character of any sort. We shall thus avoid that confusion 

 of thought which is the common accompaniment of misleading 

 terminology. " Men believe that their reason rules over words ; 



1 See chapters xx.-xxv. 



