THE SENSORIAL FUXCTION". J 57 



the eyelids is tliat of being closed, and lliej are kept open by tlie 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 Hds 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 dra^^Ti over 

 the e^^e, and this is effected by a little sti-ip of cartilage at the edge of 

 each of them, Avhich may be easily felt with the finger, and preserves 

 them in a hooplike 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 whole of its flat surface to the upper, but it evidently 

 slopes iaward, and only the outer edge of the under lid touches the upper. 

 By this means a little gutter is formed, through which the superfluous 

 moistm-e of the eye flows to the inner corner, where thei-e is a canal to 

 convey it away. By this contrivance it neither accumulates in the eye 

 nor unjjleasantly runs doTVTi the cheek. 



Along the edges of the lids are placed numerous little hollows, Avhich 

 can be plainly distraguished even in the living hoi'se by slightly tixrnina" 

 doA\ai the lid. These are the openings from the meibomian or ciliary 

 glands containing a thick and unctuous fluid, by means of which the 

 eyes are more accui'ately closed, and the edges of the lids defended from 

 the acrimony of the tears. 



The horse has no eyebrows, and the eyelashes are very peculiai-ly ar- 

 ranged. 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 fi-om above ; and, as the animal stands, particularly when he is 

 grazing, and fi-om the lateral situation of his eyes, the greater jiortion of 

 the light, and the attacks of insects, and the rolling down of moistui-e, 

 would chiefly be fi'ora 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 dii'ection. Only a small quantity of light can 

 enter from below, and therefore the lashes are thin and short ; but as, in 

 the act of grazing, insects may more readily climb up and be troublesome 

 to the eye, towards the inner angle, there the principal or only hair is 

 found on the lower lid. These apparently trifling circumstances will not 

 be overlooked by the carefal observer. 



They Avho are unacquainted mth the absurdities of stable management, 

 or who have not carefully examined the abuses that may exist in their own 

 establishments, can scarcely beheve the fooKsh 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 eyelashes are 

 generally sacrificed. What has the poor animal suffered, when, travelling 

 m the noon of day, the fall blaze of the sun has fallen upon his eyes ; and 

 how many accidents have probably happened from his being dazzled by 

 the fight, which have been attributed to other causes ! 



If the horse has no eyebrow, there are several hairs or bristles scattered 

 on the upper eyelid, and there is a projecting fold of the lid which dis- 

 charges nearly the same ofl&ce. It is more conspicuous in old horses than 

 in young ones. Some horsemen do not like to see it, and associate the idea 

 of it with weakness or disease of the eye. This is perfectly erroneous. It 

 is a pro\'ision of nature to accomplish a certain purpose, and has nothing 

 to do either with health or disease. 



On the lower lid is a useful pro^-ision to warn the horse of the near 

 approach of any object that might incommode or injure him, in the form 

 of long projecting haii'S or bristles, which are pleuteously imbued with 



