304 MENTAL FACULTIES SEC. 



inherited experience cannot have taught how to satisfy it. 

 Not until the inherited experience of proper method 

 has been acquired does instinct exist but here again the 

 impulse itself, and the endeavour to satisfy it in accordance 

 with inherited experience are difficult to separate. 



I have considered instinct as a faculty which can be called 

 into exercise by external or internal stimuli. These internal 

 stimuli consist in the temporary condition of the body, and 

 show themselves as impulses. The sexual impulse appears 

 first at a definite period of life, as hunger at a definite time 

 of day, and with them the instinct of satisfying them. If the 

 sexual organs are removed, both impulse and instinct cease. 

 Hunger we cannot remove. 



CONCLUDING EEMAKKS ON INSTINCT 



My experiments on chickens show that the exercise of 

 instincts is determined by definite inherited mental images 

 of things, e.g. of the kind of food. But I consider it especially 

 necessary again expressly to point out that it is also in a high 

 degree the general acquired faculty of learning what actions 

 are suitable, of making use of the slightest experience, which 

 enables the animals so quickly to make themselves at home 

 in the world, and not always, however it might appear so at 

 first sight, perfect instinct, i.e. the inborn complete capacity 

 for performing certain actions. 



The faculty of rapid learning implies in the particular 

 cases of its application a small remnant of independent 

 reflection, which beautifully shows how instinct arises. When 

 this reflection disappears in a particular case, we have pure 

 instinct. If we do not regard its importance, we believe we 

 have nothing but instinct before us. This explains how 

 difficult it often is to decide how much in a particular action 

 is to be ascribed to instinct. 



