392 THEORIES OF DEVELOPMENT 



grees, it has been possible to demonstrate in man the existence 

 of several characters which show Mendelian inheritance. 

 Though most of the evidence has relation to abnormal or dis- 

 eased conditions, investigations are now being made concerning 

 pedigrees of normal characters. One of the most easily ob- 

 served is the natural color of the eye. "To what extent eye 

 color may be valuable as a criterion of race it is at present im- 

 possible 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 color suggests reflections of another 

 kind. It is difficult to believe that the markc<lly different states 

 of pigmentation which occur in the same species are not as- 

 sociated with deep-seated chemical differences influencing the 

 character and bent of the individual. j\Iay not these differences 

 in pigmentation be coupled with and so become in some measure 

 a guide to mental and temperamental characteristics?'"^ 

 1 Punnctt's " Mendelism." 



