164 The Study of Animal Life part ii 



was the means of the evolution of habit as much as of 

 form. 



Mr. Romanes, starting from this as a basis, has con- 

 structed a well-reasoned and lucid theory. He supposes that 

 while many instincts have been evolved by Natural Selection, 

 such instincts being called Primary, other habits become 

 instinctive through the " lapse of intelligence." Actions 

 performed at first with mental effort, becoming after suffi- 

 cient repetition so ingrained upon the nervous system that 

 a mechanism of neuro- muscular co-ordination has been 

 established, are referred to as Secondary Instincts. He 

 imagines also a third class of Mixed Instincts in which 

 there are primary instincts that have been altered and 

 improved by intelligent variations of habit, or secondary 

 instincts that have been modified by natural selection. 



Obviously, therefore, he supposes that intelligence may 

 be a factor in the formation of any habit that may be under 

 consideration. 



But this theory of instinct becomes impossible if we accept 

 Professor Weismann's doctrine that acquired characters can 

 not be inherited (this doctrine will be discussed in a later 

 chapter). If this be true, the only possibilities are primary 

 instincts, and secondary instincts formed afresh during each 

 individual lifetime, and mixed instincts of the same nature. 



The exact antithesis to Professor Weismann's theory is 

 upheld by Professor Eimer, who believes that instincts have 

 been evolved chiefly by the perpetuation of what Mr. 

 Romanes calls secondary instincts. There is little evidence 

 that this is the case. The value of Elmer's work really lies 

 in his insistence upon the intelligent action of animals as 

 apart from purely instinctive action. 



Mr. Wallace has begun the analysis of the particular 

 forms which the intelligence of animals takes. He supposes 

 that imitation of parents and other members of the species 

 has a great influence upon the actions of individuals. He 

 has dwelt especially upon such cases as the song and nest- 

 building of birds. 



It may be pointed out as a matter for consideration that, 

 granted that parents teach their offspring, as, for instance. 



