No. 486] 



THE PROBLEM OF COLOR VISION 



theory, although the three substances could exist in a single cone, 

 each is declared to exist in a cone hy itself. This is considered 

 to be strongly in favor of the vah(ht_v of llic ^'ouno-I lehnholtz 

 theory. Since physiologists find no instance in wliich different 

 sorts of impulses are conveyed over a given nerve fiber, it is believed 

 tliat a single cone fiber can transmit only one .sort of color M-nsition. 

 The stimuli of the red, green, and blue cones respcc ti\cly arc 

 supposed to be gathered l)y .separate nerve cells of the retina, and 



only il.l. otvcn. and blue sei'isations respectivel v" I1ie nn'xing of 

 the MMi^..ti..n.. ^i^inn rj.r to the perception of sha.lo and tints, is 

 tiuM-efore acconiplisiied in the brain and not in the cones. In an 



perception of the colors of stars. The image of the star- is so 



that one cone perceives its color is invalidated by the fad that the 



rapid .succe.s.sion upon .several coiit>> which may unite in uivinu" the 

 color perception. Those who bcucve in the s|.,vihc cueruv of the 

 rod and cone fibers dismiss at oikv several .if the iheori.'. of color 

 vision. It must be nMnenibered. however, that the separation of 

 the cones into forms respoudinn- to re.l. blue, and oivm light, 

 with three corre.sponding sets of nerve cells and fillers to convey 

 these separate stimuli to the brain, does not rest upon anatomical 

 evidence. 



Physiological Laboratory 

 Harvard University 



