t/8 MANUAL OF MODERN FARRIERY 



accumulate at the inner angle of the eye, be carried 

 down the duct, which would irritate and obstruct it. 

 No sooner do any of these annoyances enter the 

 eye but they are carried off by the haw, which lies 

 concealed within the inner corner of the eye. This 

 haw is a black or pied cartilaginous substance of a 

 triangular form, concave within, and made exactly to 

 suit the globe of the eye ; while it is convex exter- 

 nally, accurately fitting the membrane lining the lid, 

 while the base of it is reduced to a thin or almost 

 sharp edge. The horse has the voluntary power of 

 suddenly protruding this from its concealment, and 

 passing it rapidly over the eyeball, clears off every 

 nuisance mixed with the tears, and then being quickly 

 drawn back, the dust or insect is wiped off as the 

 cartilage again passes under the corner of the eye. 

 In treating of disease of the haw, page 35, we 

 mentioned the barbarous practice of cutting out this 

 valuable appendage to the eye. This member is 

 destined by nature as a substitute for the want of 

 hands for wiping the eye and cleansing it from offen- 

 sive matter. This being removed, subjects the poor 

 animal to pain in its eye for life, and lays it open to 

 the constant chance of inflammation from dust or 

 small pieces of gravel being blown into it. The pain 

 they thus inflict on the horse may be easily conceived 

 by any one having dust or other extraneous matter 

 lodged between the eyelid and eye, and being without 

 hands to wipe it out. 



THE EYE AND ITS VISUAL STRUCTURE. 

 PLATE X, FIG. 8. 



The eye is of a spherical figure, yet not perfectly 

 globular ; or it may rather be considered as com- 



