94 THE HORSE. 



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

 •ami there will be an evident uncertainty in tlie putting down of his teet : 

 •hese things, however, have been overlooked by tiie careless and inexpert, 

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

 eye, little or nothing of tiiis characteristic gait or manner can be perceived ; 

 yet, although 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, an<l 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 fault, by overriding his willing and valu- 

 able beast, and causing a determination of blood to the eye, wbich proveil 

 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 laterally, his 

 field of observation must be materially lessened. 



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

 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 sud- 

 denly brought into an intense light, and the pupil is closed, these bodies 

 present a singular appearance, being squeezed out from between 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 injurious; but their prin- 

 cipal 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 directions 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, m, gives a duplicature 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 

 uid<nov/n way, connected with this black paint behind. Wall-eyed horseSj 

 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 An," vol. iii. 

 p. 201, says : — " The loss of one eye does not enfeeble sight, because the other acquires 

 g-reaier enerery, though it nuuli contracts tlie field of vision. It is said to render the 

 conception erring; and the ca.^c of mis-judgment of di.-tances is the one commonly 

 brought forward to show this. All I can say on this point is, that tlie best hunter I ever 

 possessed — a horse gifted with extraordinary powers for leaping — was a one-eyed hor^e; 

 and this animal carried me through a hunting season, without to my recollection makinp 

 one single blunder in leaping." 



