90 THE HORSE. 



part which will rarely deceive, and is more easily got at, viz. the mem- 

 brane lining the nose. If the edge of the nostril be lifted up, the colour 

 of the nostril will faithfully indicate the degree of chest affection, and of 

 general inflammation or fever. 



Covering the back part of the eye, and, indeed, four-fifths of the globe of 

 the eye, is the sclerotica, k. It is an exceedingly strong membrane, com- 

 posed of fibres interweaving with each other, and almost defying the pos- 

 sibility of separation. An organ so delicate and so important as the eye, 

 requires secure protection. 



This is a highly elastic membrane. It is necessary that it should be so, 

 when we consider that the eye is surrounded by several, and very powerful 

 muscles, which must temporarily, and even for the purposes of vision, alter 

 its shape. The elasticity of the sclerotica is usefully exhibited, by its 

 causing the globe of the eye to resume its former and natural shape, as 

 soon as the action of the muscle ceases. 



The sclerotica has very few blood vessels ; is scarcely sensible ; and its 

 diseases, except when it participates in general disturbance or disorganiza- 

 tion, are rarely brought under our notice. We therefore pass on to the 

 cornea. 



The cornea is, or we should wish it to be, the only visible part of the 

 horse's eye, for we repeat, that the exhibition of much white about it is a 

 symptom of wickedness. The cornea fills up the vacuity which is left by 

 the sclerotica, in the fore part of the eye, and although closely united to 

 the sclerotica, may be separated from it, and will drop out like a watch 

 o-lass. It is not round, but wider from side to side, than from top to bot- 

 tom ; and the curve rather broader towards the inner than the outer corner 

 of the eye, so that the near eye may be known from the off, after it is 

 taken from the head. 



The convexity or projection of the cornea is a point of considerable im- 

 portance. The prominence of the eye certainly adds much to the beauty 

 of the animal, but we shall see presently, when we consider the eye as the 

 organ of sight, that by being too prominent, the rays of light may be ren- 

 dered too convergent, and the vision indistinct ; or if the cornea be small 

 and flat, the rays may not be convergent enough, and perfect vision de- 

 stroyed ; and in either case, the horse may unpleasantly start, or suddenly 

 and dangerously turn round. An eye neither too prominent nor too flat 

 will be nearest to perfection. 



It ought to be perfectly transparent, and any cloudiness or opacity is 

 the consequence of disease. It is an exceedingly firm and dense mem- 

 brane, and can scarcely be pierced by the sharpest instrument. The cornea 

 is composed of many different plates, laid over one another, and, between 

 each, at least in a state of health, is a fluid, which is the cause of its trans- 

 parency ; and the evaporation of which, after death, produces the leaden or 

 glazed appearance of the eye. When it appears to be opaque, it is not 

 often, and never at first, that the cornea is changed. It is the conjunctiva, 

 the membrane that spreads over it, that now carries through its numerous 

 vessels white blood instead of that which was perfectly pellucid or clear ; 

 or there is a secretion of a milky fluid, over or througii the conjunctiva, 

 leaving the cornea beneath unaffected. If, however, the inflammation of 

 the conjunctiva continues, a thick fluid is at length thrown out, between 

 the plates of the cornea, and the cloudiness is converted into perfect 

 opacity. 



There is nothing which deserves so much attention from the purchaser 

 of a horse, as the perfect transparency of the cornea over the whole of its 



