DISEASES OP" THE EYE. 289 



digestive organs, may bccouK' coniplicati'd by this affection. From 

 the close relation between the brain and eye — alike in the blood ves- 

 sels and nerves — disorders of the first lead to affection of the second, 

 and the same remark applies to the persistent irritation to Avhich the 

 jaws are subjected in the course of dentition. So potent is the last 

 agency that we dread a recurrence of ophthalmia so long as dentition 

 is incomplete, and hope for immunity if the animal completes its 

 dentition without any permanent structural change in the eye. 



iSi/mptom^. — The symptoms will vary according to the cause. If 

 the attack is due to direct physical injury, the inlhunmation of the 

 eyelids and superficial structures nuiy be quite as marked as that of 

 the interior of the eye. If, on the other hand, from general causes, or 

 as a complication of some distant disease, the affection may be largely 

 confined to the deeper structures, and the swelling, redness, and ten- 

 derness of the superficial structures will be less marked. "When the 

 external coats thus comparatively escape, the extreuie anterior edge of 

 the white or sclerotic coat, Avhere it overlaps the border of the trans- 

 parent cornea, is in a measure free from congestion, and, in the ab- 

 sence of the obscuring dark pigment, forms a whitish ring arounil the 

 cornea. This is partly due to the fact that a series of arteries (cili- 

 ary) passing to the inflamed iris penetrate the sclerotic coat a short 

 distance behind its anterior border, and there is therefore a uiaiked 

 difference in color between the general sclerotic occupied between 

 these congested vessels and the anterior rim from which they arc 

 absent. Unfortunately, the pigment is often so abundant in the 

 anterior part of the sclerotic as to hide this symptom. In internal 

 ophthalmia the opacitv of the cornea may be confined to a zone 

 around the outer inargin of the cornea, and even this may be a bluish 

 haze rather than a deep, fleecy white. In consequence it becomes impos- 

 .sible to see the intei'ior of the chauiber for the a(]ueous humor and the 

 condition of the iris and pupil. The a(iueous humor is usually turbid, 

 and has numerous yellowish-white flakes floating on its substance 

 or deposited in the lower i)art of the chamber, so as to cut off the 

 view of the lower portion of the iris. The still visible portion of 

 the iris has lost its natural, clear, dark luster, which is replaced by 

 a brownish or yellowish sere-leaf .color. This is more marked in 

 ])roportion as the iris is inflamed, and less so as the inflannnaticm is 

 confined to the choroid. The quantity of flocculent deposit in the 

 chamber of the aqueous humor is also in direct ratio to the inflaunna- 

 tion of the iris. Perhaps the most marked feature of internal ()ph- 

 thalmia is the extreme and painful sensitiveness to light. On this 

 account the lids are usually closed, but when opened the pupil is 

 seen to be narrowly closed, even if the animal has been kept in a 

 darkened stall. Exceptions to this are seen when inflammatory effu- 



36444°— 10 19 



