94 ZOOLOGY. 



more complex nature, which constitute both what we call 

 instincts and what we call habits. The former term covers 

 all those which are determined by. the inherited structure 

 of the nervous system, while the latter includes those which 

 owe their existence to structural characters in the nervous 

 system that have been produced during the life of the 

 animal. 



Habits can only be formed as a result of those still 

 higher modes of action which we call "rational" or ".deli- 

 berate " or "voluntary " actions which differ from all grades 

 of reflex action by reason of their involving the association of 

 ideas a term under which we include all kinds of imagina- 

 tion, memory, and reason. A young rabbit who by mistake 

 eats some unpleasant-tasting vegetable is not likely to eat 

 it again, because the image of the same vegetable focussed 

 on the retina of his eye will not merely give rise in his brain 

 to the simple sensations of colour, form, etc., as in the case 

 of an unknown plant, but these in turn will awaken a vivid 

 sense of the unpleasantness of taste associated with them. 

 In this and similar ways a rabbit is educated, and all 

 education is concerned with the association of ideas. 



The distinction between deliberative actions and instinctive 

 ones thus appears perfectly definite ; but in practice the line 

 is hard to draw, as instinctive actions may be started, or 

 modified, or stopped in the course of deliberative ones. 

 Moreover, deliberative actions, when often repeated, pass 

 into habits, in which association of ideas no longer takes 

 any part. This is strikingly shown in the case of civilized 

 men, in whom actions of a most complicated kind, most 

 slowly and painfully acquired, become apparently instinctive. 

 Writing from dictation, for example, is carried on without 

 a thought of how a word should be spelled or how each 

 letter should be shaped. Reading aloud from a book may 

 be carried on without a thought of the spelling of the words, 

 and even without a thought of the sense. 



13. Consciousness. It is apparently only in really 

 deliberative actions that consciousness is at all involved. It 

 is of course impossible to know whether an animal is con- 

 scious or not, and, in arguing from analogy, we have not 



