168 Dr Esser on the Luminomness of the Eyes, 



moistened, the intensity of the light was increased to a certain 

 extent, but faded away with the decomposition of the eye it- 

 self, and eternal darkness reigned in the stead of glorious light. 

 I believe I observed a difference in the degree of light, accord- 

 ing to the colour of the cat ; and it is certain, that black and 

 fox-coloured cats evolve a brighter and more conspicuous light 

 from their eyes, than grey and white ones, though there may 

 undoubtedly be exceptions to this distinction *. 



Besides cats, many domestic as well as other animals, are 

 furnished with luminous eyes. 



Under similar circumstances as above, I observed that the 

 light of a dog's eye, as was the case in my experiments on cats, 

 vanished suddenly as soon as I had completely darkened the 

 room where the dog was. I observed the eyes of another dog 

 sparkle when he was irritated, and in the corner of a room that 

 was faintly lighted. The eyes of the animal protruded very 

 much, glittered brilliantly, and the pupils were dilated to an 

 unusual degree. The colour of the light, which was commonly 

 yellow, changed more or less as the rays of light fell on the eyes 

 of the animal, and exhibited the following appearances. When 

 a small body of rays of light fell oh the eye, the light was of a 

 fiery redness, and sometimes so strong, that after I looked a 

 long time attentively at it, my own eyes experienced a disagree- 

 able sensation. When there was a great body of rays, the light 

 was green or yellow, sometimes bluish. In respect to this 

 change in the colour of the hght, I was inclined to think, that 

 it might be owing as much to the motions of the animaPs eyes 

 as to the body of light that fell upon them. This change was 

 different in different dogs, and in some it was not at all observa- 

 ble. Further, the eyes of every dog placed in the same situa- 

 tion, shone, but the intensity of the light varied with the indi- 

 viduals. 



I have observed luminousness in the eyes of horses, sheep and 

 hares, which was different, however, in colour and strength. 



Many appearances of light have been observed in the eyes of 

 human beings. Treviranus mentions, that G. T. L. Sachs, 

 and his sister, both belonging to albinoes, had phosphorescent 



• Bened. PreTOst's Memoir on the Luminousness of the Eyes of animals, 

 will be given in our next number. 



