l8o MANUAL OF MODERN FARRIERY 



in the eye only over one-twelfth of an inch, yet is 

 the change of place in the image distinctly perceived 

 throughout its whole progress." 



i t i. The points where the rays, having passed the cornea, 



converge by the refracting power of the lens. 

 j. The cornea, or horny and transparent portion, which is 

 covered by the conjunctiva uniting different parts 

 together. 



The cornea fills up the vacuity which is left by 

 the sclerotica ; but although it is closely united with 

 it, may be easily separated and will drop out. A 

 prominent eye adds greatly to the beauty of a horse, 

 and this will depend upon the projection of the 

 cornea. But if too prominent, the rays of light 

 may be rendered too convergent, which will produce 

 indistinct vision. If it be small and flat, the rays 

 may not be sufficiently convergent, which will produce 

 imperfect vision. An eye that is moderately convex 

 will be found best ; because, when either too pro- 

 minent or too flat, the horse is liable to starting and 

 shying upon a road. The cornea is quite transparent 

 in the healthy eye, and when cloudiness is observ- 

 able, then it is an indication of disease. 



In the purchase of a horse, the utmost attention 

 should be given to the condition of the cornea. 

 Perfect transparency over the whole surface is in- 

 dispensable. The eye should be carefully examined 

 in the manner pointed out at page 37 ; first in front, 

 and afterwards through its substance. 



, k. The crystalline, or glassy lens, situated behind the pupil 

 and in front of the vitreous humour, which is so 

 named from a supposed resemblance to melted glass ; 

 it is a clear gelatinous fluid, very much resembling 

 the white of an egg. 

 /. The sclerotica, a hard, firm coat, covering the whole of 



