DICHROMATIC VISION 181 



cases. The subjects match yellow (566 — 570 jxfx) with unsaturated 

 complementary blue. They confuse blue-green with blue, greenish 

 yellow with grey and rose-purple, yellowish green with bluish violet, 

 orange with reddish purple. They appear to be a reduction form of 

 trichromatic vision. Tritanopes call the red end of the spectrum 

 red, the violet end green or blue. Vintschgau and Hering's case 

 was congenital, but showed changes in the red and green, thus 

 approximating to total colour blindness. There was a neutral band 

 in the yellow (598- -568 /x/x), but the violet end also appeared 

 colourless, though of good luminosity and without marked shortening. 

 Yellow and blue could be matched with grey, but a match could not 

 be made between red and green. The most saturated green was at 

 532 /xfx, and the site of maximum brightness was between 558 fifj, and 

 565 /x/x. In Bonders' case the spectrum was shortened at each end 

 and the neutral band in the yellow occupied one-third of the spectrum. 

 Tritanopia appears to be commonest in cases of detachment of the 

 retina. It is simulated in cases of jaundice and sclerosis of the crystal- 

 line lens, these being due to absorption by yellow pigment. The same 

 ambiguity may arise in people with unusually dense macular pig- 

 mentation^. 



Bibliography of Cases of Tritanopia 



Stilling. Klin. Monatshl.f. Augenhlk. xm. Supij]. 2, 41, 1875 ; xiv. Suppl. 3, 1, 1875. 



Cohn. Studien uber angeb. Farhenhlindheit, 139, Breslau, 1879. 



Donders. Ann. d'ocul. xxxiv. 212, 1880. 



Holmgren. Med. Zentralbl. xym. ; Centralbl. f. Augenhlk. v. 476, 1881. 



Hermann. Inaug. diss. Dorpat, 1882. 



Wundt. Phil. Studien, vm. 173, 1892. 



Vintschgau. Arch. f. d. ges. Physiol. XL\Tn. 431 ; Lvn. 191, 1894. 



Hering. Arch. f. d. ges. Physiol. Lvn. 308, 1894, 



Konig. Sitz. d. Akad. d. Wiss. xxxiv. 718, 1897 (Pathological). 



Piper. Ztsch. f. Psychol, u. Physiol, d. Sinnesorg. xxxvin. 155, 1905 ^ Pathological). 



Levy. Arch. f. Ophth. Lxn. 464, 1906. 



CoUin and Nagel. Ztsch. f. Sinnesphysiol. xli. 2, 74, 1906 (Pathological). 



Schenck. Arch. f. d. ges. Physiol, cxviu. 161, 1907. 



Krienes. Ztschr. f. Augenhlk. xx. 392, 1908. 



Kollner. Die Stdrungeii des Farbensinnes, Berlin, 1912 (Bibliography), 



^ Cf. Abney, p. 343 ; Proc. Roy. Soc. Loud. xlix. 1891 ; Hess, Arch. f. Anat. lxi. 29, 

 1908. 



