^4 ^HE HORSE. 



over some obstacle, when there is actually nothing to obstruct his passage ; 

 and there will be an evident uncertainty in the putting down of his feet : 

 these things, however, have been overlooked by the careless and inexpert, 

 and a blind horse has been bought as a sound one. In blindness of one 

 eye little or nothing of this characteristic gait and manner can be perceived ; 

 yet althouo^h a one-eyed horse may not be absolutely condemned for the 

 common business of the carriage or the road, he is generally worthless as 

 a hunter, for he cannot measure his distances, and will run into his leaps*. 

 Many a sportsman, puzzled and angry at the sudden blundering of his 

 horse, or injured by one or more stunning falls, have found a very natural, 

 although unexpected explanation of it in the blindness of one eye, and that 

 perhaps produced through his own fauh, by over-riding his wiUing and 

 valuable beast, and causing a determination of blood to the eye, which 

 proved fatal to the delicate texture of the retina. Even for the carriage or 

 the road, he is, however, sadly deteriorated ; for, his eyes being placed la- 

 terally, his field of observation must be materially lessened. 



Let the size of both pupils be carefully noticed before the horse is re- 

 moved from the stable, and, as he is led to the door, observe whether they 

 both contract, and equally so, with the increase of light. If the horse 

 should be first seen in the open air, let it be observed whether the pupils 

 are precisely of the same size ; then let the hand be placed over each eye 

 alternately, and held there for a little while, and let it be observed whether 

 the pupil dilates with the abstraction of light, and equally dilates in each eye. 



Hanging from the upper edge of the pupil of the horse, are found 

 two or three round black bodies, as large as millet seeds. When the 

 horse is suddenly brought into an intense light, and the pupil is closed, 

 these bodies present a singular appearance, being squeezed out from be- 

 tween the edges of the iris. An equal number, but much smaller, are 

 attached to the edge of the lower portion of the iris. Their general use is 

 probably to intercept portions of light which would be troublesome or in- 

 jurious ; but their principal function is accomplished during the act of 

 grazing. They are larger on the upper edge of the iris, and are placed on 

 the outer side of the pupil, evidently to discharge the same function which 

 we have attributed to the eyelashes, to obstruct the light in those direc- 

 tions in which it would come with greatest force, both from above and even 

 from below, while, at the same time, the field of view is perfectly open, so 

 far as it regards the pasture on which the horse is grazing. 



Our cut, 771, gives a duplicatiu-e of the iris, or the back surface of it. 

 This is called the uvea, and it is covered with a thick coat of black mucus, 

 to arrest the rays of light, and to prevent them from entering the eye in 

 any other way than through the pupil. The colour of the iris is, in some 

 unknown way, connected with this black paint behind. Wall-eyed horses; 

 whose iris is white, have no uvea. 



We now arrive at a body on which all the important uses of the eye 

 mainly depend, the crystalline lens, g, so called from its resemblance to a 

 piece of crystal, or transparent glass. It is of a thick jelly-like consistence, 

 thicker and firmer towards the centre, and convex on each side, but more 



* Mr. W. Percivall, however, in his excellent Lectures on Veterinary Art, vol. iii. p. 

 20 1 , says, " The loss of one eye does not enfeeble sight, because the other acquires greater 

 energy, though it much contracts the field of vision. It is said to render the conception 

 erring, and the case of mis-judgment of distances is the one commonly brought forward to 

 show this. All I can say on this point is, that the best hunter I ever possessed, a horse 

 gifted with extraordinaiy powers for leaping, was a one-eyed horse, and this animal carried 

 me through a hunting season, without, to my recollection; making one single blunder in 

 leaping." 



