166 INSECTS AND HEREDITY 



nerve-mechanisms of instinct are transmitted, and owe 

 their inferiority as compared with the results of education 

 to the very fact that they are not acquired by the indi- 

 vidual in relation to his particular needs, but have arisen 

 by selection of congenital variation in a long series of 

 preceding generations. 



' To a large extent the two series of brain-mechanisms, 

 the "instinctive" and the "individually acquired", are in 

 opposition to one another. Congenital brain-mechanisms 

 may prevent the education of the brain and the develop- 

 ment of new mechanisms specially fitted to the special 

 conditions of life. To the educable animal — the less there • 

 is of specialised mechanism transmitted by heredity, 

 the better. The loss of instinct is what permits and 

 necessitates the education of the receptive brain. 



' We are thus led to [the] view that it is hardly possible 

 for a theory to be further from the truth than that 

 espoused by George H. Lewes and adopted by George 

 Romanes, namely that instincts are due to " lapsed " 

 intelligence. The fact is that there is no community 

 between the mechanisms of instinct and the mechanisms 

 of intelligence, and that the latter are later in the history 

 of the development of the brain than the former, and can 

 only develop in proportion as the former become feeble 

 and defective.' 1 



The bearing of Insect Warning and Mimetic Colours 

 upon the supposed Hereditary Transmission of Experience 

 by their Vertebrate Enemies. 



Adaptations which facilitate the education of entomo- 

 phagous vertebrates are so 'perfect and so wide-spread 

 in insects that they constitute a large body of indirect 

 evidence in favour of the non-transmission by heredity of 

 the results of experience. Fritz Muller, in his celebrated 

 theory of mimicry, suggested that the object of the likeness 

 between the warning colours of specially-protected species 

 was to reduce the danger from the attacks of young and 

 inexperienced enemies. This is all the more interesting 



1 From the Jubilee Volume of the Soc. de Biol, Paris, 1899. 

 Reprinted in Nature, vol. lxi, 1900, pp. 624-5. 



