72 



The cornea may be next viewed from various positions, 

 noting carefully its curvature, its opacities, the presence or 

 absence of ulcers, abscesses, vascularization, swellings or 

 new growths. The location, color and limitations of the 

 opacities should first be determined. The weaker the opac- 

 ity or cloudiness the more blue the color ; intense opacities 

 are white. Black opacities of the cornea signify pigmenta- 

 tion from iris adhesions or from blood stains. Striped and 

 pearl like opacities, with sharp limitations, point to scars or 

 chronic changes in the cornea; chalk spots result from the 

 employment of silver and lead salts in wounds and ulcers of 

 the cornea. Viewing the cornea in profile, or from one side, 

 will enable one to locate the opacity, revealing in a degree 

 what layers of the cornea are involved; and to a certain ex- 

 tent enables one to determine the curvature of the cornea, 

 especially in partial or total staphyloma and extremely flat or 

 very conical forms of the cornea. If the transparency of the 

 cornea will permit, investigate the aqueous humor, search- 

 ing for the gray, floculent exudate or the yellow, sediment- 

 ary pus exudate, or the red colored exudate in blood effu- 

 sions; these may be present in penetrating wounds of the 

 cornea, iritis and moonblindness. 



The color, condition of the outer surface, movements and 

 attachments of the iris should next be examined. The iris 

 may become grayish brown by the deposition of inflamma- 

 tory products in its substance, or become gray from the de- 

 posit of an exudate on its surface. The bluish-green color 

 of the iris, manifest after one or two attacks of periodic op- 

 thalmia, is due to an atrophied (shrinking) condition of the 

 iris. Occasionally in cattle a tubercular growth develops 

 from the iris and completely fills the aqueous chamber of 

 the eye. The iris may be attached by inflammatory adhe- 

 sions to the capsule of the lens (as in iritis or moonblind- 

 ness); or it may thus adhere to the posterior surface of the 

 cornea (a result of penetrating wounds and ulcers). By the 

 use of atrojiine, if the pupil is small or contracted, or ese- 

 rine if the j^upil is large or expanded, these adhesions may 



