• Diseases of the Eye. 319 



"best unsightly, and implies not only defect but often disease as 

 well. 



4tli. The iris should be lustrous, uniform in color and 

 ■even in surface. Whether dark brown as in the horse, or yel- 

 low as in the dog, it should be brilliant. Any part that lacks 

 lustre, being lighter brown, or yellow and dull like a dead leaf, 

 usually indicates previous disease and a tendency to further 

 trouble. Albinos and those in which the pigment' is congenitally 

 absent in patches must be considered as exceptions, yet, even in 

 them, the pecuharity cannot be held to add to the beauty. 



5th. All the Media (Cornea, aqueous humor, lens and vit- 

 reous) must be perfectly clear and translucent. The slightest 

 cloudiness or opacity in any of these is a serious blemish and 

 usually indicates disease, past or present. 



6th. The pupil should promptly and freely respond to 

 light and darkness by contraction and expansion. Absence or 

 tardiness of movement indicates impaired vision, from disease of 

 the eye, its nerves, or their nerve centres. 



7th. Each cornea should have a median convexity, uni- 

 form in all directions implying the absence of myopia, 

 presbyopia and astgimatism. Any deviation from this will 

 interfere with the perfection of sight, and endanger shying and 

 other troubles. 



8th. Under ordinary light the pupil should appear black 

 ■throughout. In the larger animals such dilation of the pupil as 

 to expose the tapetum lucidum under such circumstances implies 

 impaired vision (amblyopia, amaurosis), inflammation of the 

 iris or undue intraocular pressure. A white color or spot shows 

 •cataract. 



Qth. The lids must be open and mobile without excessive 

 dilation. Tardily moving or semi-closed lids, distorted by scar 

 or angle, everted or inverted, are unattractive and usually imply 

 disease in the eye, nerves or brain. 



loth. The unpigmented portion of the sclera should be 

 light pink. The dark red of congestion and the pallor of anaemia 

 are equally objectionable. 



nth. The tears must be clear, limpid and confined within 

 the lower lid. Any milkiness, flocculency or overflow is in- 

 ■dicative of disease. 



