THE SENSORIAL FUNCTION. 83 



may be readily moved without friction, and by a sheath of considerable Jensity anu 

 firmness, and especially where it is most needed, on the external and supenoi 

 portions. 



The adipose matter exists in a considerable quantity in the orbit of the eye of the 

 horse, and enables that organ readily to revolve by the slightest contraciion of the 

 muscles. By the absorption of this fatty matter in sickness or old age, the eye is not 

 only to a certain degree sunk in the orbit, but the roof of the orbit posterior to the 

 frontal bone, being deprived of its support, is considerably depressed. Our work 

 shall not be disgraced by any farther reference to the rascally contrivance by which 

 this indication of age is in some degree removed. 



In front the eye is supported and covered by the lids, which closing rapidly, pro- 

 tect it from many an injury that threatens — supply it with that moisture which is 

 necessary to preserve its transparency — in the momentary act of closing give a certain 

 and sufficient respite to a delicate organ, which would otherwise be fatigued and 

 worn out by the constant glare of daj- — defend it when the eye labours under inflam- 

 mation from the stimulus of light, — and, gradually drooping, permit the animal to 

 enjoy that repose which nature requires. 



Extending round both lids, and, it may be almost said, having neither origin nor 

 insertion, is a muscle called the orbicularis, or circular muscle. Its office is to close 

 the lids in the act of winking or otherwise, but only while the animal is awake. 

 When he sleeps, this is effected by another and very ingenious mechanism. The 

 natural state of the eyelids is that of being closed ; and they are kept open by the 

 energy of the muscles whose office it is to raise the upper lid. As sleep steals upon 

 the animal, these muscles cease to act, and the lids close by the inherent elasticity 

 of the membrane of which they are composed. 



The skin of the lid is, like that of the ear, exceedingly fine, in order to prevent 

 unnecessary weight and pressure on such a part, and to give more easy and extensive 

 motion. The lids close accurately when drawn over the eye, and this is effected by 

 a little strip of cartilage at the edge of each of them, which may be easily felt with 

 the finger, and preserves them in a hoop-like form, and adapts them closely to the 

 eye and to each other. The lower cartilage, however, does not present, towards the 

 inner corner of the eye, the wliole of its flat surface to the upper, but it evidently 

 slopes inward, and only the outer edge of the under lid touches the upper. By this 

 means, a little gutter is formed, through which the superfluous moisture of the eye 

 flows to the inner corner, where there is a canal to convey it away. By this con- 

 trivance it neither accumulates in the eye, nor unpleasantly runs down the cheek. 



Along the edges of the lids are placed numerous little hollows, which can be 

 plainly distinguished even in the living horse by sliglitly turning down the lid. 

 These are the openings into numerous small cells containing a thick and unctuous 

 fluid, by means of which the eyes are more accurately closed, and the edges of the 

 lids defended from the acrimony of the tears. 



The horse has no eyebrows, and the eyelashes are very peculiarly arranged. The 

 rows of hair are longest and most numerous on the upper lid, and especially towards 

 the outer or temporal corner, because the light comes from above; and, as the animal 

 stands, particularly when he is grazing, and from the lateral situation of his eyes, the 

 greater portion of the light, and the attacks of insects, and the rolHiiir down of 

 moisture, would chiefly be from the outside or temples. Towards the inner corner 

 of the upper lid there is little or no eyelash, because there is no probable danger or 

 nuisance in that direction. Only a small quantity of light can enter from below, and 

 therefore the lashes are thin and short; l)ut as, in the act of grazing, insects may 

 more readily climb up and be troublesome to the eye, towards the inner ansfle, there 

 the principal or only hair is found on the lower Ha. These apparently trifling cir- 

 cumstances will not be overlooked by the careful observer. 



They who are unacquainted with the absurdities of stable management, or who 

 have not carefully examined the abuses that may exist in their own establishments, 

 can scarcely believe the foolish and cruel practices of some carters and grooms. 

 "When the groom is anxious that his horse should be as trim and neat all over as art 

 can make him, the very eye-lashes are generally sacrificed. What has the poor 

 animal suffered, when, travelling in the noon of day, the full blaze of the sun has 



