30 INTRODUCTION. 



individually, and from motives changing according to cir- 

 cumstances. This is one of the greatest results of comparative 

 psychology in the second half of this century, and the time 

 is near when no one will any longer dispute it." 



There are certainly many actions of an instinctive kind, 

 but if they cannot be explained as the result of reflection, 

 imitation, habit, instruction, experience, and consideration, 

 or from a specially fine development of a sense, and other 

 peculiarities of organisation they depend in each case, as 

 has been shown, on propensities inherited from parents, or 

 mental habits and capacities, or, to put it anatomically and 

 physiologically, on inherited predispositions of the brain and 

 nervous system for certain psychical function-grooves 

 briefly, on what may be called inherited memories. These 

 tendencies and habits, perhaps even ideas of a certain sort, are 

 acquired by parents and ancestors during their lives in a defi- 

 nite manner, generally very gradually and in the course of very 

 long spaces of time ; these are transmitted, when they bring 

 or have brought advantage in the struggle for existence to 

 their possessors, and are handed down intensified from 

 generation to generation. Artificial breeding may wor.k in 

 the same fashion as do the struggle for existence and natural 

 selection in Nature. For instance, the well-known and oft- 

 cited instinct of the hound or the pointer is nothing more 

 than the lengthening by art and training of a brief pause, 

 which all beasts of prey are wont to make at the sight or 

 scent of their quarry just before springing at it, partly to 

 gather up their forces, partly to fix attention as strongly as 

 possible on the object to be seized. None the less must 

 the pointer puppy, which has brought with it into the world 

 a tendency to this action, inherited from its parents, be 

 trained into a perfect and useful hound by education, 

 punishment, and experience. In like manner is it with the 

 instinct or inclination of sheep-dogs to herd sheep, or of the 

 greyhound to course hares, or of the Newfoundland to rescue 

 men, as also with the love and attachment shown to men 

 especially by the dog, originally sprung from wild animals, 

 apparently from wolves and jackals. The famous migrations 

 of birds have only arisen gradually through a slow pressure 

 of cold from the poles to the equator, and are now continued 

 by transmission from generation to generation. Thence 

 comes it that migratory birds kept in cages grow uneasy 



