AND ITS DISEASES. 159 



the horse, the sight occasionally returns, but I have never seen this in the 



The occasional glittering of the eyes of the dog has been often observed. 

 The cat, the wolf, some carnivora, and also sheep, cows, and horses, occa- 

 sionally exhibit the same glittering. Pallas imagined that the light of these 

 animals emanated from the nervous membrane of the eye, and considered 

 it to be an electrical phenomenon. It is found, however, in every animal 

 that possesses a tapetum lucidum. The shining, however, never takes place 

 in complete darkness. It is neither produced voluntarily, nor in conse- 

 quence of any moral emotion, but solely from the reflection that falls on 

 the eye. 



