246 Animal Intelligence 



alterations of the animal's ' natural ' or ' normal ' structure 

 as by cuts, bruises, blows, and the like, - - and deprivations 

 of or interference with its ' natural ' or ' normal ' activities, 

 as by capture, starvation, solitude, or indigestion, are in- 

 tolerable. But interference with the structure and func- 

 tions by which the species is perpetuated is not a sufficient 

 criterion for discomfort. Nature's adaptations are too 

 crude. 



Upon examination it appears that the pernicious states of 

 affairs which an animal welcomes are not pernicious at the 

 time, to the neurones. We learn many bad habits, such as 

 morphinism, because there is incomplete adaptation of all 

 the interests of the body-state to the temporary interest of 

 its ruling class, the neurones. So also the unsatisfying 

 goods are not goods to the neurones at the time. We neglect 

 many benefits because the neurones choose their immediate 

 advantage. The neurones must be tricked into permitting 

 the animal to take exercise when freezing or quinine when 

 in a fever, or to free the stomach from certain poisons. 



Satisfaction and discomfort, welcoming and avoiding, thus 

 seem to be related to the maintenance and hindrance of the 

 life processes of the neurones rather than of the animal as a 

 whole, and to temporary rather than permanent mainte- 

 nance and hindrance. 



The chief life processes of a neurone concerned in learning 

 are absorption of food, excretion of waste, reception and 

 conduction of the nerve impulse, and modifiability or change 

 of connections. Of these only the latter demands comment. 



The connections formed between situation and response 

 are represented by connections between neurones and neu- 

 rones, whereby the disturbance or neural current arising in 

 the former is conducted to the latter across their synapses. 

 The strength or weakness of a connection means the greater 



