164 MENDELISM CHAP. 



extent eye-colour may be valuable as a criterion of 

 race it is at present impossible to say, but if it is 

 ever to become so, it will only be after a searching 

 Mendelian analysis has disclosed the factors upon 

 which the numerous varieties depend. 



A discussion of eye-colour suggests reflections of 

 another kind. It is difficult to believe that the 

 markedly different states of pigmentation which 

 occur in the same species are not associated with 

 deep-seated chemical differences influencing the 

 character and bent of the individual. May not these 

 differences in pigmentation be coupled with and so 

 become in some measure a guide to mental and 

 temperamental characteristics ? In the National 

 Portrait Gallery in London the pictures of cele- 

 brated men and women are largely grouped accord- 

 ing to the vocations in which they have succeeded. 

 The observant will probably have noticed that there 

 is a tendency for a given type of eye- colour to pre- 

 dominate in some of the larger groups. It is rare 

 .to find anything but a blue among the soldiers and 

 sailors, while among the actors, preachers, and 

 orators the dark eye is predominant, although for 

 the population as a whole it is far scarcer than the 

 light. The facts are suggestive, and it is not im- 

 possible that future research may reveal an intimate 

 connection between peculiarities of pigmentation and 

 peculiarities of mind. 



The inheritance of mental characters is often 

 elusive, for it is frequently difficult to appraise the 

 effects of early environment in determining a man's 

 bent. That ability can be transmitted there is no 

 doubt, for this is borne out by general experience, 



