1,56 TllK SIi:XSOKIAL FUXCTIOX. 



and bulk, and that seeming diflference arises from tlic larger or smaller 

 opening between tlie lids— and the lid is thick, and especially if there is 

 any puckering towards the inner corner of the Hds, that eye either is 

 diseased, or has lately been subject to disease ; and, particularly, if one 

 eye is smaller than the other, it has at no great distance of time been 

 inflamed. 



The eye of the horse enables us with tolerable accuracy to guess at his 

 temper. If much of the white is seen, the buyer should pause ere he com- 

 pletes his bargain ; because, although it may, yet very i-arely, happen that 

 the cornea or transparent part is unnaturally small, and therefore an un- 

 usual portion of the white of the eye is seen, experience has sho^Am that 

 this display of white is dangerous. The miscliievous horse is slyly on the 

 look out for opportunities to do mischief, and the frequent backward direc- 

 tion of the eye, when the white is most perceptible, is only to give surer 

 eifect to the blow which he is about to aim. 



A cursory description of the eye, and the uses of its different parts, 

 must be given. 



The eyes are placed at the side of the head, but the direction of the 

 conoid cavity which they occupy, and of the sheath by which they are 

 surrounded "witliin the orbit, gives them a prevailing direction forwards, 

 BO that the animal has a very extended field of vision. We must not 

 assert that the eye of the horse commands a whole sphere of vision ; but 

 it cannot be denied that his eyes are placed more forward than those of 

 cattle, sheep, or swine. He requires an extensive field of vision to warn 

 him of the approach of his enemies in his wild state, and a direction of 

 the orbits considerably forward, in order to enable him to pursue Avith 

 safety the headlong course to Avhich we sometimes urge him. 



The eyeball is placed in the anterior and most capacious part of the 

 orbit, nearer to the frontal than the temporal side, ANdth a degree of promi- 

 nence vai'ying Avith different indiAriduals and the will of the animal. It 

 is protected by a bony socket beneath and on the inside, but is partially 

 exposed on the roof and on the outside. It is, hoAvever, covered and 

 secured by thick and poAverful muscles — by a mass of adipose matter 

 which is distributed to various -parts of the orbit, upon which the eye may 

 be readily moved Avithout friction, and by a sheath of considerable density 

 and firmness, and especially Avhere it is most needed, on the external and 

 superior portions. 



The adipose matter exists in a considerable quaiitity in the orbit of the 

 eye of the horse, and enables that organ readily to rcA^olve by the slightest 

 contraction 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 depriA^ed 

 of its support, is considerably depressed. 



In front the eye is covered and protected by the lids, which, closing 

 rapidly, secure it from many an injury that threatens— diffuse over it 

 that moisture Avhich is necessary to preserve its transparency — in the 

 momentary act of closing give a certain and sufficient respite to a dehcate 

 organ, wliich would otherAvise be fatigued and AA'orn out by the constant 

 glare of day — defend it Avhen the eye labours under inflammation from 

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

 that repose Avhich nature requii'cs. 



Extending round both lids, and, it may be almost said, liaA'ing neither 

 origin nor insertion, is a muscle called the orbicularis palpebrarum, or 

 circular muscle. Its office is to close the lids in the act of AAdnking or 

 otherAAase, but only while the animal is aAvake. When he sleejos this is 

 effected by another and A'cry ingenious mechanism. The natural state of 



