THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



MAY 1856. 



XLI. On a peculiar case of Colour Blindness. 

 By John Tyndall, F.R.S. ^jc* 



A CASE of colour blindness has been recently bi'ougbt under 

 my notice by Mr. White Cooper, of so singular a character 

 that I think even the brief description of it which the pressure 

 of other duties permits me to give will not be without interest to 

 the readers of the Philosophical Magazine. 



Out of eleven hundred and fifty-four cases examined by Dr. 

 George Wilson of the University of Edinburgh, and recorded by 

 him in his truly interesting and valuable work on Colour Blind- 

 ness f, only one instance was found in which the sufferer was 

 aware of the loss he had sustained. This was the case of a 

 medical practitioner in Yorkshire, who in November 1849 was 

 thrown from his horse. " After rallying from the collapse which 

 immediately succeeded the accident, he suffered from severe pain 

 in the head, delirium, mental excitation approaching almost to 

 mania, loss of memory, and other symptoms of cerebral disturb- 

 ance On recovering sufficiently to notice distinctly objects 



around him, he found his perception of colours, which was for- 

 merly normal and acute, had become both weakened and per- 

 verted, and has since continued so. . . . Flowers have lost more 

 than half their beauty for him, and he still recalls the shock 

 which he experienced on first entering his garden after his re- 



* Communicated by the Author. 



t At paj^e l.'^7 I find some observations of mine referred to. 1 would 

 here remark, that whatever observations or experiments I have hitherto 

 made on this subject were merely repetitions or modifications of those of 

 Dove or Hclmholtz, whose excellent memoirs I had the pleasure of intro- 

 ihic-ing into this country. 



Phil. May. S. 4. Vol. 11. No. 73. May 1856. Z 



