130 THE SENSORIAL FUNCTION. 



rather it is not found on any part on which the rays proceeding from the objects 

 could fall. It does not occupy the smallest portion of what maybe called the field of 

 vision ; but, in its place a bright variegated green is spread, and more over the 

 upper part than the lower, because the animal's food, and the objects which it is 

 of consequence for him to notice, are usually below the level of his head thus, 

 by suffering the impression to remain longer on the retina, or by some portion 

 of light reflected from this variegated bed on which the retina reposes, or in 

 some other inexplicable but efficient way, enabling the animal, even in compa- 

 rative darkness, to possess a power of vision equal to his wants. 



The reader may see in the dusk, or even when duskiness is fast yielding to 

 utter darkness, the beautiful sea-green reflection from the eye of the horse. It 

 is that lucid variegated carpet of which we are now speaking. 



Who is unaware that in the fading glimmering of the evening, and even in 

 the darker shades of night, his horse can see surrounding objects much better 

 than his rider ; and who, resigning himself to the guidance of that sagacious and 

 faithful animal, has not been carried in safety to his journey's end, when he 

 would otherwise have been utterly bewildered ? 



If the reader has not examined this beautiful pigment in the eye of the horse, 

 he should take the earliest opportunity of doing so. He will have a beautiful 

 illustration of the care which that Being who gave all things life has taken that 

 each shall be fitted for his situation. The horse has not the intelligence of man, 

 and may not want for any purpose of pleasure or improvement the vivid picture 

 of surrounding objects which the retina of the human being presents. A thou- 

 sand minute but exquisite beauties would be lost upon him. If, therefore, his 

 sense of vision may not be so strong during the day, it is made up to him by 

 the increased power of vision in the night. 



Perfectly white and cream-coloured horses have a peculiar appearance of the 

 eyes. The pupil is red instead of black. There is no black paint or brilliant 

 carpet. It is the choroid coat itself which we see in them, and not its covering; 

 and the red appearance is caused by the numerous blood-vessels which are 

 found on every part of that coat. 



When we have to treat of other domestic animals, we shall see how this 

 carpet is varied in colour to suit the situation and necessity of each. In the ox 

 it is of a dark green. He has not many enemies to fear, or much difficulty in 

 searching for nourishment, and the colour of the eye is adapted to his food. In 

 the cat and all his varieties, it is yellow. We have heard of the eyes of the 

 lion appearing like two flaming torches in the night. There are few of our 

 readers who have not seen the same singular glare from the eyes of the domestic 

 cat. In the wolf, and likewise in the dog, who, in his wild state, prowls chiefly 

 at night, it is grey. In the poor unjustly-persecuted badger, who scarcely dares 

 to crawl forth at night, although sheltered by the thickest darkness, it is white; 

 and the ferret, who is destined to hunt his prey through all its winding retreats, 

 and in what would be to us absolute darkness, has no paint on the choroides. 



Tracing the choroides towards the fore part of the eye, we perceive that it is 

 reflected from the side to the edge of the lens, n, and has the appearance of 

 several plaits or folds. They are actually foldings of the membrane. It is not 

 diminished in size, but it has less space to cover, and there must be duplicatures 

 or plaits. They are usefully employed in the place in which we find them. 

 They prevent the passage of any rays of light on the outside of the lens, and 

 which, proceeding forward in various directions, and uncondensed by the power 

 of the lens, would render vision confused or imperfect. These folds of the 

 choroides are called the ciliary processes. 



Within the cornea, and occupying the fore part of the eye, is the aqueous 

 humour., p, so termed from its resemblance to pure water. It is that by which 



