In the inner corner of the eye is a semilunar fold of the mucous membrane, the cavity of which is directed outwards. This is called the membrana nictitans, and resembles somewhat the third eyelid in birds.

The purpose of this structure is to protect the eye, and by it dust and irritants are swept, as it were, from the eyeball.

This membrane is subject to inflammations resulting from injuries, irritants, and possibly constitutional diseases. During the existence of an inflammation the part becomes red and swollen, partially covering the eyeball obstructing the sight, and giving rise to a profuse flow of tears. Considerable pain often attends the affection, which if persistent may-result in a permanent enlargement of the membrane, and consequent unsightly deformity, as well as becoming a source of inconvenience and annoyance to the animal.

Treatment

The acute inflammation should be controlled by frequent bathing and, the use of the following. -

℞ Zinci Sulph. gr.iij Aquae ℥ ij.

Ft. Mist. Sig. Drop into the eye three or four times daily.

This astringent lotion or the use of borax and camphor water, ten grains of the former to one ounce of the latter, will in nearly all cases prove sufficient. When the swelling of the membrane first appears, if treatment be at once applied, the affection should yield very readily. Other causes than those acting locally, should be sought for and removed. The presence of constitutional disorders is highly probable when both eyes are affected; in such cases it is usual to find the general health of the animal much impaired. Dogs confined between decks, on long voyages, indifferently cared for and having insufficient exercise, sometimes contract the disease. The usual treatment by kennel-men is frequent bathing with warm milk. This has its advantages, but should not displace the astringent lotion advised.

If the enlargement of the membrane does not readily lessen under the use of applications, it should be snipped with blunt scissors.