Miscellaneous Intelligence. 



143 



4. On a peculiar case of Color Blindness ; by John Tyndall, F.R.S., 

 &c., (Phil. Mag., May, 1856.) — A case of color blindness has been re- 

 cently brought 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 Color Blindness, 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 Novem- 

 ber, 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 disturbance On 



recovering sufficiently to notice distinctly objects around him, he found 

 his perception of colors, which was formerly normal and acute, had be- 

 come both weakened and perverted, 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- 

 covery, at finding that a favorite damask rose had become in all its parts, 

 petals, leaves, and stem, of one uniform dull color ; and that variegated 

 flowers, such as carnations, had lost their characteristic tints." 



The case of Captain C, which I have to describe, is one of these rare 

 instances. The sufferer is a seaman, and ten or twelve years ago was ac- 

 customed, when time lay heavy on his hands, to occupy it by working 

 at embroidery. Being engaged one afternoon upon a piece of work of 

 this description, and anxious to finish a flower (a red one, he believes), he 

 prolonged his labors until twilight fell, and he found it difficult to select 

 the suitable colors. To obtain more light he went into the companion, 

 or entrance to the cabin, and there continued his needlework. While 

 thus taxing his eyes, his power of distinguishing the colors suddenly van- 

 ished. He went upon deck, hoping that an increase of light would re- 

 store his vision. In vain. From that time to the present he has remained 

 color blind. 



My first examination of Captain C. took place in the house of Mr. 

 Cooper. Being furnished with specimens of Berlin wool, such as that 

 with which the patient had been accustomed to work, I placed before 

 him a skein which he at once, and correctly, pronounced to be blue. For 

 this color he has a keen appreciation, and I have never known him make 

 a mistake regarding it. Two bundles of worsted, one a light green and 

 the other a vivid scarlet, were next placed before him : he pronounced 

 them to be both of the same color ; a difference of shade was perceptible, 

 but both to him were drab. A green glass and a red glass were placed 

 side by side between him and the window : he could discern no difference 

 between the colors. A very dark green he pronounced to be black ; the 

 purple covering of the chairs were also black ; a deep red rose on the 

 wall of the room was a mere blotch of black ; fruit, partly of a bright 

 red and partly of a deep green, were pronounced to be of the same uni- 

 form color. A cedar pencil and a stick of sealing-wax placed side by 



