80 



THE MODERN SYSTEM 



CHAPTER VI. 



THE EYE AND ITS DISEASES. 



THE EYE. 



The eye is such an important organ, and 

 the structure of such sublime grandeur, that 

 we cannot in justice to our readers pass it 

 over slightly ; but shall endeavour to give as 

 full a description as we possibly can of this 

 piece of natural mechanism. 



MUSCLES OF THE EYE. 



The muscles of the eye, of which the 

 orbicularis first comes under our notice, which 

 surrounds, and is attached to the Vjones of 

 the orbit ; and though these fibres are 

 attached to the lower eye-lid, it seems 

 scarcely for the purpose of motion, as this lid 

 is to appearance stationary ; this muscle passes 

 under the loose skin of the upper eye-lid, 

 which has great motion ; the office of this 

 muscle is to close the eye-lid perfectly, or in the 

 act of winking, which is performed involunta- 

 rily ; therefore, this muscle in sleep is in action. 

 There is an antagonist to this muscle, the levator 

 palpebrce, arising from the posterior part of 

 the orbit, passes over the orbit, and contiguous 

 to the lachrymal glands, which are placed in 

 the hollow of the orbit above the eye; this 

 pair of muscles is in almost unceasing action, 

 and like all other muscles, they would become 



weary, but by acting in opposition they are 

 rested at intervals ; for when the eyes are shut, 

 the orbicularis is in action ; when awake the 

 levator palpebrce ; but this is relaxed by the 

 act of winking, which is clearly one intention 

 of winking ; another is allowing the tears to 

 pass over the orbit, which performs their 

 office of removing extraneous matter, by 

 means of the action of the eye-lids. 



To move the eye, there are four straight 

 muscles, two oblique, and one retractor, the 

 powers of which are very superior to those of 

 the human subject ; but nature is diversified 

 in her gifls ; thus, some have wings, whilst 

 we have brains and hands, which more than 

 compensate for all deficiencies. 



But to be acquainted with the different func- 

 tions, and organizations of the eye of the 

 Horse, it requires greater attention than per- 

 sons at first sight are aware ; there being a 

 muscle attached to the Horse's eye called the 

 retractor muscle, which the human subject 

 has not. But, going back to the straight 

 muscles, we will begin with the levator oculi, 

 which arises from the posterior part of the 

 orbit, goes over the retractor muscle, and is 

 attached to the sclerotic coat; it is for the 

 purpose of directing the eye upwards, the eye 

 always acting in unison with these muscles. 



