58 SENSATION AND REACTION 



by an accurately directed sting. But it seems 

 wholly unreasonable to pretend that by chance 

 or experiment the worm could have acquired 

 its marvellous skill in dissection, or that a 

 complicated chain of events, affecting the 

 behaviour of two generations, could have been 

 elaborated by casual or tentative experience. 

 The fascinating pages of M. Fabre support this 

 illustration by hosts of others, which show 

 that, even if habits may in some cases be in- 

 herited, instinctive behaviour is too elaborate to 

 have been derived from them. The various com- 

 plexities of instinctive conduct must have origin- 

 ated in such mutations, or " sports," as have 

 produced the different species of plants and ani- 

 mals. And, after all, its manifestations are not 

 more wonderful than the instinctive functioning 

 of our vital organs. 



A nerve cell is sensitive to an impression and 

 exhibits a reaction. The behaviour of a photo- 

 graphic plate under the action of light is,- so far, 

 precisely similar. But in the cell these processes 

 appear to be attended by something that is 

 lacking in the plate by a feeling of " awareness " 

 or " consciousness." To some this will appear a 

 monstrous hypothesis ; it invests a nerve cell 

 with attributes that are peculiar to the brain. 

 But the brain is but a mass of nerve cells, and 

 must derive its power from its constituents. Dur- 

 ing sleep the brain is quiescent : if the finger of 

 a sleeping person is pinched, it is sharply with- 

 drawn although he is not awakened. This, it 

 may be urged, is a purely automatic action, and 

 does not prove that any awareness arose. But 

 the pinch may move the sleeper to dream that a 



