THE MIND OF MAN 279 



previous experience of injury. The new-born infant neither 

 fears nor hates anything. An ability to track game, and 

 other like characters, are said to be instinctive in some savages. 

 But this is much the same as saying that an ability to read 

 and write is instinctive in Englishmen. Presumably the 

 Australian native, for instance, is not born with a knowledge 

 of the appearance, habits, and tracks of the emu or the 

 kangaroo. There is not any evidence even that he is more 

 capable than the child of civilized parents of acquiring the 

 knowledge. It is natural, however, since he has been trained 

 under the best tuition from infancy to tracking, that he 

 should be more proficient than the European who attempts 

 to acquire proficiency much later and under much less 

 favourable auspices. 



447. The kind of stimulus (use) that causes any physical 

 structure to develop is always much the same for that 

 structure. Thus the human hand is employed mainly in 

 grasping, pushing, and otherwise manipulating objects. It 

 is subjected to pressures and strains that vary somewhat in 

 degree, but little in kind, with the occupation of the 

 individual. Subjected to great and constant pressures and 

 strains it tends to grow relatively large, strong, and coarse ; 

 subjected to lesser pressures and strains it tends to be 

 relatively smaller, weaker, and more delicate. But the 

 tendencies to growth in it are such that a comparatively 

 limited amount of use is sufficient to develop it into a 

 normal adult hand. A greater amount of use results only in 

 minor differences. Probably the amount of stimulus received 

 by the hand, in different members of the community, varies 

 more than that received by any other structure for example, 

 eyes, tongue, lungs, heart, legs. Nevertheless the indi- 

 vidual members of a community, even when reared under 

 almost identical conditions, may differ greatly in their 

 physical characters. Thus one person may be tall, strong, 

 and dark, while another is short, weak, and fair. It is 

 evident, therefore, that the physical differences are, to a very 

 large extent, due to germinal variations. We see the truth 

 of this yet more plainly when we contrast individuals of 

 different races. No one will doubt that a Scandinavian and an 

 African Bushman reared as members of the same household, 

 and therefore under very similar conditions, would present 

 immense physical contrasts. The structures of both would 

 grow under the influence of use, and all this growth would be 

 an acquirement ; but the direction of the growth and the ex- 

 tent of it would be rightly limited by their inborn tendencies. 



