Hillside. 161 



operation, we have only reflex action, and yet such operations 

 must be transmitted directly to the offspring, and be in- 

 herent in the individual at the time of birth. We say that 

 it is by instinct that the young cuckoo ejects from the nest 

 the rightful occupants, whom it supplants, and whose place 

 it takes, so far as the attentions of the parents are concerned. 

 There can be no real mental operation performed by the 

 young bird at this early age. Its action, resulting as it does 

 in the destruction of the young birds whose place in the 

 nest it usurps, and in its own advancement, must depend 

 upon the imprint it has received of the experiences of suc- 

 cessive generations transmitted by heredity during thou- 

 sands of years. 



An action like this, which we could not perform without 

 the guidance of experience, when it is performed by a young 

 animal devoid of experience, and without knowledge of the 

 purpose for which it is performed, is instinctive. It cannot 

 be said to be due to reflex action, for in reflex action 

 muscular work is effected, or brought about by a suitable 

 stimulus, without the intervention of a mental process, or of 

 mental cognisance. There can be no doubt that the young 

 cuckoo is aware of what it does, for when any of the birds 

 which have been ejected are replaced in the nest, it will turn 

 them out again and again. 



In much the same manner the spinning of a spider's web is 

 instinctive, for if the web be broken, the spider will renew 

 the broken part. The spinning of cocoons by caterpillars, 

 in which to hybernate or pass the winter, and the selection 

 of suitably protected spots for the same purpose by moths, 

 butterflies and other insects, are further instances of instinc- 

 tive acts. On a level with these may be considered the 



