6 ANIMAL INDIVIDUALITY [CH. 



has not the requisite machinery, the requisite com- 

 plication of brain and muscle. 



Lastly it is due to increased adaptability, which 

 depends mainly upon increased power of choice. 

 Adaptability seems to be a property soon acquired 

 by a complex and unstable substance, or rather 

 mixture of substances, like protoplasm. Roux (16) 

 by extending Darwin's idea of Natural Selection or 

 survival of the fittest from individuals to the organs 

 and tissues, the cells and varieties of protoplasm within 

 the individual, has shown that some measure of 

 adaptability, or useful response to changed conditions, 

 becomes a common property of all living things. 

 This, though very important, has been slow in 

 action, merely automatic, and therefore limited in 

 its usefulness, the result, to speak in metaphors, not 

 of choice but of habit. What we call choice has only 

 become fully realized through a special arrangement 

 of special tissue the brain. 



Says Bergson : "A nervous system with neurones 

 placed end to end in such wise that, at the extremity 

 of each, manifold ways open in which manifold 

 questions present themselves, is a veritable reservoir 

 of indetermination " (1, p. 133). Such is the nervous 

 system of man : and whatever value we assign to the 

 idea of indetermination, whether we believe in the 

 reality of choice and free-will, or think that they are 

 only apparent, due to the relativity of our mental 



