508 DR WILLIAM PEDDIE ON A CASE OF COLOUR BLINDNESS. 



the spectrum to be extended to its normal length, substitute the word " grey " for 

 " black," and we have Mr A.'s case. 



I append some illustrations of Mr A.'s colour matches. All matches are placed 

 together in columns — four matches in the left-hand column, four in the central column, 

 and two pairs of matches in the right-hand column. Though he sees no difference in 

 colour between the members of the upper pair in the last column, Mr A. can readily 

 distinguish them, and describes the one with a blue tinge as having a dirty or washed- 

 out appearance. 



$U 



20 Jill 



