268 ESSAYS OF A BIOLOGIST 



the basis of our mental individuality, as our per- 

 sonal being, is the result of a long process of organ- 

 ization. We come into the world with a set of in- 

 stinctive and emotional reactions only waiting their 

 proper stimuli to be fired off, with a capacity for 

 learning, for amassing experience, and a capacity 

 for modifying our instincts and our behaviour ac- 

 cording to our experience. We incorporate experi- 

 ence in ourselves, and in so doing we alter the orig- 

 inal basis of our reactions; a strongly emotional ex- 

 perience colours all that is closely associated with it; 

 and so after birth we are continually making our 

 mental microcosm not only larger but qualitatively 

 more complex, in exactly the same way as before 

 birth our body grew not only in size, but also in com- 

 plexity of organization. 



Parts of experience or of inherited tendencies may 

 fail to become organically connected with the main 

 parts of our minds, simply because attention has 

 never been focussed on them, or has not attempted to 

 bring them into relation with the rest. They are, 

 shall we say, like bricks which might have been used 

 in a building, but have been left lying on the ground 

 by the workmen. 



Still more remarkable are the methods by which 

 harmony is achieved in the personal mind. It is 

 obvious that a conflict of any sort between parts of 

 the mind will waste energy, will prevent a clear-cut 

 reaction being given in either direction, and so con- 

 stitute a grave biological disadvantage by making us 



