24 THE HORSE AND HIS RIDER. 



of man. The former can take in a wider range in con- 

 sequence of the lateral position of the eyes and their 

 distance apart; and when the animal, with its head 

 down, is quietly grazing, it can see objects with faci- 

 lity in every direction round it. Man's vision is more 

 limited in range, but it is probable more acute, be- 

 cause the black lining of the human eye renders it a 

 more perfect camera obscura, and gives more vivid- 

 ness to the pictures formed within it. The lining 

 membrane of the horse's eye is of a beautiful sea 

 green colour, in consequence of which it absorbs so 

 much the less light, and thereby affords increased 

 power of vision in the night. Every rider must be 

 aware from experience that his horse can discern sur- 

 rounding objects, when the gloom of evening conceals 

 them from his own eyesight. All animals who have 

 to seek their food by night have the interior of the 

 eye more or less bright ; in the wolf and the dog it is 

 grey; and in all varieties of the cat species it is 

 yellow ; the eyes of the lion have been compared to 

 two fiaming torches in the night. There are indi- 

 viduals of the human race called Albinos, whose eyes 

 look red like those of ferrets, from the absence of the 

 usual black pigment, and these persons are almost 

 blind by day, but see with ease in what to other men 

 seems thick darkness. 



