338 ENVIRONMENT AMONG MEN 



matter, so to speak, upon which mental processes work, it will be 

 considered in Chapters XIX and XX. It is important to dis- 

 tinguish the influence of the environment in this latter respect 

 from the sense in which it is considered in this chapter. The 

 failure to do so has vitiated many contributions to the subject. 

 It is felt that the environment is somehow of great influence in 

 social life and it is not realized that, if in the respect in which it is 

 considered in this chapter we find reason to conclude that its 

 influence is not great, there is another field in which its influence 

 may be established. 



When considering the influence of the environment on man, 

 it is convenient to distinguish between physical and mental 

 characters. Mental characters may be considered under the head 

 of the intellect, the disposition, and the temperament. It must, 

 however, be clearly understood that this is merely a distinction 

 convenient for our present purpose which is not based upon, and 

 does not imply, any fundamental distinction. Mental characters, 

 such as the instinct of gregariousness, and physical characters, 

 such as head form, are for our purpose merely characters resulting 

 from the play of certain stimuli upon a certain germinal consti- 

 tution. 



2. It is remarkable how little on the whole is known with 

 regard to the influence of the environment on man. For the most 

 part we have to depend upon observations as distinguished from 

 experiments. Though a few experiments have been made, some 

 deliberately but others accidentally, we are for the most part in 

 the position with regard to man that we should be with regard to 

 other animals, had we only such observations to go on as those 

 quoted respecting the size of marine molluscs, the variation in 

 the coat of the tiger, and the changes in the sparrow and the 

 periwinkle when introduced into America. Though such observa- 

 tions may strongly suggest certain conclusions as to the part played 

 by the environment, no definite or precise results can be reached. 



We may first consider some evidence bearing upon the influence 

 of particular factors such as exercise and climate. We may 

 disregard those rare cases of extreme modifications deliberately 

 induced, such as the distortion of the shape of the head or of the 

 feet by pressure. These extreme modifications approximate to 

 mutilations such as amputation of the finger-joints or the knocking 

 out of the incisor teeth. 



