1884.] on the Darwinian Theory of Instinct. 133 



from reflex action. Unless we assume that a new-born infant, for 

 example, is conscious of sucking, it is as great a misnomer to term 

 its adaptive movements in the performance of this act instinctive, as 

 it would be similarly to term the adaptive movements of its stomach 

 subsequently performing the act of digestion. 



Next, instinct implies hereditary knowledge of the objects and 

 relations with respect to which it is exercised; it may therefore 

 operate in full perfection prior to any experience on the part of the 

 individual. When the pupa of a bee, for instance, changes into an 

 imago, it passes suddenly from one set of experiences to another — the 

 diiference between its previous life as a larva and its new life as an 

 imago being as great as the difference between the lives of two 

 animals belonging to two different sub-kingdoms ; yet as soon as its 

 wings are dry it exhibits all the complex instincts of the mature 

 insect in full perfection. And the same is true of the instincts of 

 vertebrated animals, as we know from the researches of the late 

 Mr. Douglas Spalding and others. 



Again, instinct does not imply any necessary knowledge of the 

 relation between means employed and ends attained. Such know- 

 ledge may be present in any degree of distinctness, or it may not be 

 present at all ; but in any case it is immaterial to the exercise of 

 the instinct. Take, for example, the instinct of the Bembex. This 

 insect brings from time to time fresh food to her young, and 

 remembers very exactly the entrance to her cell, although she has 

 covered it with sand, so as not to be distinguishable from the sur- 

 rounding surface. Yet M. Fabre found that if he brushed away 

 the earth and the underground passage leading to the nursery, 

 thus exposing the contained larva, the parent insect " was quite 

 at a loss, and did not even recognise her own offspring. It seemed 

 as if she knew the doors, nursery, and the passage, but not her child." 



Lastly, instinct is always similarly manifested under similar cir- 

 cumstances by all the individuals of the same species. And, it may 

 be added, these circumstances are always such as have been of frequent 

 occurrence in the life-history of the species. 



Now in all these respects instinct differs conspicuously from every 

 other faculty of mind, and especially from reason. Therefore to 

 gather up all these differentioe into one definition, we may say that 

 instinct is the name given to those faculties of mind which are con- 

 cerned in consciously adaptive action, prior to individual experience, 

 without necessary knowledge of the relation between means employed 

 and ends attained; but similarly performed under similar and fre- 

 quently recurring circumstances by all the individuals of the same 

 species. 



Such being my definition of instinct, I shall now pass on to con- 

 sider Mr. Darwin's theory of the origin and development of instincts. 



Now, to begin with, Mr. Darwin's theory does not, as many suppose 

 that it does, ascribe the origin and development of all instincts to natural 

 selection. This theory does, indeed, suppose that natural selection 



