﻿260 
  Rood 
  — 
  Color-vision 
  and 
  the 
  Flicker 
  Photometer. 
  

  

  two 
  of 
  which 
  were 
  not 
  previously 
  suspected. 
  All 
  three 
  persons 
  

   were 
  quite 
  unable 
  to 
  stand 
  the 
  Holmgren 
  worsted 
  test. 
  

  

  Red. 
  Green. 
  Violet 
  blue. 
  

  

  J. 
  Alsberg 
  __. 
  30-3 
  88-1 
  100- 
  

  

  Mr. 
  W 
  35-6 
  .85-5 
  100* 
  

  

  Mr. 
  35-3 
  100- 
  93-9 
  

  

  Older 
  persons 
  appear 
  to 
  be 
  more 
  or 
  less 
  subject 
  to 
  another 
  

   kind 
  of 
  defect 
  in 
  their 
  color-vision, 
  due, 
  as 
  Dr. 
  S'oyes 
  suggests, 
  

   to 
  a 
  yellow 
  coloration 
  of 
  the 
  crystalline 
  lens. 
  I 
  have 
  not 
  

   studied 
  the 
  subject 
  much, 
  and 
  can 
  give 
  the 
  result 
  of 
  only 
  one 
  

   case 
  : 
  it 
  was 
  obtained 
  by 
  the 
  use 
  of 
  the 
  standard 
  above 
  

   described. 
  

  

  Red. 
  Green. 
  Yiolet 
  blue. 
  

  

  100 
  7'7-2 
  72- 
  

  

  