An account of the different diseases to which the organ of vision is liable may conveniently deal, in the first instance, with the eyelids, which are frequently implicated in one way or another in disease or injury affecting the globe.

Blows inflicted intentionally or by accident are the most common form of injury to the eyelids, and it is often the case that the inflammation, with swelling and redness of the lining membrane extending over the front of the eye and reflected on the insides of the lids, are the only symptoms which result from the blow, unless it has been sufficiently severe to cause a contused wound. Exactly the same kind of symptoms will be present when the inflammation is the result of a cold, or febrile condition of the system, or of the introduction of an irritating substance under the lids, and it is therefore impossible to be quite certain whether the inflammation, swelling, and discharge of tears observed are due to one or other of the causes named unless there is some history to assist the diagnosis.

Any manual examination of the diseased eye naturally excites the animal's fears, particularly should he be unable to see the operator who is engaged in manipulating the part, and unless there is some reason to suspect that the irritation is caused by a foreign body which has entered the eye, it is better to leave the diseased parts alone until the inflammation is diminished.

The first step in the treatment should be to place the animal in a position where there is only a subdued light - entire exclusion of light is not necessary. Fomentations of warm water should then be applied, by squeezing the water from a sponge laid on to the skin above the injured organ, or by fixing a piece of soft rag in such a position that the water may run from it over the swollen eye, the least pressure to the diseased parts being avoided. As the inflammation subsides, the lids will gradually open and assume their normal character, and it will now be easy to see if the injury has affected the transparent cornea. Sometimes a white line running obliquely across the front of the eye will suggest a cut from the lash of a whip; in other cases there may be a general opacity over the whole of the transparent structure, and in other instances the symptoms which are apparent will satisfy the examiner that the disease in the lids which was taken to be the result of injury was merely the indication of a much more serious malady - periodic ophthalmia, - which has yet to be considered.