372 



THE AMERICAN NATURALIST [Vol. XLI 



vision the red end of the spectrum is lost, and the green-bhie por- 

 tion is its brightest part, he considers that the photo-chemical 

 substance of the rods is attuned only to the green-blue light, which 

 is perceived as colorless. Later this photo-chemical substance be- 

 comes sensitized in two stages, first to include the green-yellow, 

 and then the yellow-red, which however are still perceived as 

 colorless light. Thus a gray molecule like that of ]\Irs. Franklin's 

 first stage is constructed. It occurs in the color blind peri{)heral 

 cones. The formation of color-reacting groupings in the partly 

 sensitized gray molecule leads, according to Schenck, to those 

 forms of human vision in which the red end of the spectrum is 

 shortened. 



Observations upon the color perception of young children do 

 not support these developmental theories. Holden and Bosse ^ 

 tested two hundred children by placing before them square pieces 

 of colored paper attached tt) a gray background of similar bright- 

 ness. If the child made an effort to grasp the scpuire, its color 

 must have been perceived. It was found that the average child 

 would react to all colors by the tciilli month, the red end of the 

 spectrum causing response a little earlier than the violet end. 

 When ribbons of six spectral colors were i>laee(l before children 

 of from seven to twenty-four months, red was selected first; orange 

 or yellow second an.l lliinl; an.l -reen, blue and violet last of all. 

 Naoel^' .h,n\e<l his child „t' tu entx -ei-ht nu.i.t h. each of the spectral 



him their names. Ued an.! -reen were learned .-asilv, l>nt l)lne 

 ^^a. acquired uilh -.vater dillicuilN than anx other <-ol'or, in<.lnd- 

 ing violet, (ireen, violet, and red were preternMl; l.iack, yellow, 

 white, gray, and blue ha<l secon.lary rank. ( )ther exf.eriments 

 with the color perception of children have givtMi ditVerent r<>snlt-. 

 It is clear, however, that children are not known to pass from a 

 color l)lind stage, through one of yellow-bhu/ vision, to a discriini- 



