54 



This position of the eye enables him, m some 

 degree, to see behind him, and to kick against 

 an adversary with greater certaint}-. 



The pnpil, or sight (as it is commonly called), 

 is of a circular form in the human eye, but in 

 the horse it is oblong. This form is peculiar to 

 all grazing animals, and gives them the advan- 

 tage of seeing objects horizontally to a much 

 greater extent than is the case with the human 

 being. 



The horse's eye, also, in common with that 

 of other grazing animals, has an additional 

 muscle seated immediately behind it. This 

 muscle is adapted for the purpose of retracting 

 the eye Avithin the orbit, to shield it from in- 

 jury, as well as to suspend it in the action of 

 grazing. 



The horse's eye differs also from the human 

 in being provided with a thick cartilaginous or 

 gristly membrane, at the anterior corner. This 

 membrane is common to most quadrupeds, as 

 well as to birds. It is known amongst farriers 

 and grooms by the term Hawes, and so univer- 

 sally ignorant are they of its use, that they 

 consider it as a disease, and generall}' remove 

 it by cutting it away. The use of this mem- 

 brane is to wipe off dust or hay seeds, or any 

 extraneous substance, that may happen to fall 

 on the surface of the eye; the bad consequences 



