i 4 o INSECTS AND HEREDITY 



of insects is of value in two ways. First, we are made to 

 realize the importance of our study : by the contemplation 

 of its relation to one majestic example we are prepared for 

 the belief that our subject is essential for the solution of 

 all the widest and deepest problems concerned with organic 

 nature as a whole. Secondly, the attempt for the first 

 time to marshal the whole of the evidence supplied by the 

 study of insects will make it possible to strengthen and 

 amplify certain parts, and thus render the whole fabric 

 better balanced and more stable. 



I should wish at the outset to express my indebtedness 

 to the columns of Nature by means of which nearly the 

 whole of the controversy has been followed. We are 

 happy in the possession of a single journal in which dis- 

 cussions on general scientific questions are, by common 

 consent, carried on. 



'Acquired Characters' defined. 



Before beginning a discussion it is important to remove 

 any possibility of doubt or uncertainty as to the precise 

 meaning of the terms which are employed. The word 

 ' acquired ' as used in this controversy has been the source 

 of as much confusion as the word * mimicry '. Just as 

 almost every one who hears of ' mimicry ' for the first 

 time assumes that the word means a power of intentional 

 imitation, so the inexperienced think that an acquired 

 character is any new structure which a species has gained 

 in the course of its history. 'Why should we not consider 

 every character acquired as an "acquired character"?' they 

 not unnaturally ask. And the answer is the same in both 

 cases. Because these ordinary and untechnical words 

 were given a special and technical meaning by the writers 

 of memoirs which have become classical. In spite of 

 all inconvenience both words are, in their scientific use, 

 historic, and we must reckon with the fact that they 

 have a special meaning which differs from their ordinary 

 meaning. 



Erasmus Darwin was, I believe, the first to use 

 'acquired' in this restricted sense. 'Fifthly,' he says, 

 ' all animals undergo transformations which are in part 



