VARIATION OF INSTINCT IN DEFINITE LINES. 225 



among animals, but it may be said in general that, as the 

 faculty of imitation depends on observation, it is found in 

 greatest force, as we should expect, among the higher or more 

 intelligent animals — reaching its maximum in the monkeys, 

 where, as is well known, it passes into ludicrous extremes. 

 And in this connection it is interesting to observe that 

 a child begins to imitate very early in life, and that the 

 faculty goes on developing during the first year or eighteen 

 months, after which it remains stationary for a time, and is 

 then of much service in developing language.* With growing 

 intelligence, this faculty subsequently declines, and in after 

 life may be said to stand in an inverse relation to originality 

 or the higher powers of the mind. Therefore among idiots 

 below a certain grade (though of course not too low), it is 

 usually very strong and retains its supremacy through life, 

 while even among idiots of a higher grade, or the " feeble- 

 minded," a tendency to undue imitation is a very constant 

 peculiarity. The same thing is conspicuously observable in 

 the case of many savages ; so that in view of all these facts 

 we must conclude that the faculty of imitation is one very 

 characteristic of a certain area of mental evolution, and there- 

 fore that within the limits of this area it must conduce in no 

 small degree to the formation of instinct.f 



* Fee Prever, loc. cit., pp. 170-182, where a number of detailed obser- 

 vations on this head are given. lie says that the first imitative movement begins 

 n- early as the fifteenth week in protruding the lips when anyone performs 

 this action before the child. [This action seems to come naturally to young 

 children, and may 1 think probably have some hereditary connection with tho 

 tame morement as so strongly pronounced in the orangoutang. For a picture 

 of inch protrusion in this animal, see Darwin. Expression of Emotions, p. HI.] 

 Towardi t he end of the Bret year imitative movements become more numerous 

 and more quickly learnt, and the child takes active pleasure in their perform" 

 ance. At twelve month* Preyer observed his child repeating in its dreams 



imitative movements which had made a strong impression on it w bile awake, 



— t.g., blowing with the mouth. Later still, complicated imitative movements 

 arc performed for mere amusement, as is apparently the case with monkeys. 



t With reference to imitation in connection with instinct, 1 think i* is 

 desirable here again to express my opinion already given in Animal intiVi- 

 genet, on the theory published by Mr. Wallace, in bis Natural Selection, 

 that the nidiflcation ox birds is due to the young hirds consciously imitating 

 the structure of the nests in which they have themselves been reared the 

 characteristic nidiflcation of each ipecdes of bird being thus maintained. 1 

 have advanced in An imal Intelligence sundry general considerations, which 1 

 though! suiiieieiit to negative this theory on i priori grounds ; but dnoe then 

 I have found among Mr. Darwin's M8S a letter which describee the results 

 of the tesl experiment which Mr. Wallace himself suggests. This experiment 

 it to r> a r young birds from the egg in an artificial nesl or inoubator unlike 



