290 COLOUR IN NATURE chap. 



haired belong to the Teutonic races ; in other words, 

 the difference in hair-colour corresponds to all those 

 profound mental and moral differences which separate 

 Celt from Saxon. That the mental and moral dif- 

 ferences are associated with physical ones hardly 

 needs proof to the biologist, but there are fortunately 

 some exact observations. During the course of an 

 extended series of observations on the specific gravity 

 of the blood. Dr. E. Lloyd Jones found that this was 

 markedly greater in dark-eyed persons than in light- 

 eyed ones, and he is of opinion that the difference is 

 fundamentally a racial one. Further, there is reason 

 to believe that the dark-haired people are better able 

 to stand prolonged dosing with drugs like mercury 

 than the fair-haired ones ; and, according to Beddoe, 

 the dark-haired persons in Britain are more prone to 

 phthisis than the fair. It thus seems that just as the 

 phthisical tendency and the other characters tend to 

 eliminate the dark people from cold climates, so ap- 

 parently the fair people are less fitted to survive, or 

 at least less likely to become dominant, in hot 

 countries. Facts of this kind have probably an 

 important bearing upon the coloration of mammals 

 in general. The constancy of the coloration, and 

 the closeness of its connection with the constitution, 

 are at least of much interest in relation to the 

 general question. 



The Origin of Melanin 



As to the direct relation of the amount of pig- 

 ment to the general metabolism, many would say 

 that the pigment is directly derived from the 



