The pupil of the eye should contract when the horse comes out into the light. If it does not, the eye is blind, or at least unsound. Such eyes have an unnatural appearance which should attract the attention of the alert examiner, but he will be very apt to overlook the blindness if the horse is led out into the bright sunshine. Where a horse has recently become blind from periodic ophthalmia (moon blindness), he may still be able to detect a bright light, and so when exposed to sunshine, may throw up his head and look directly at the sun. This act makes the examiner liable to consider the eyes sound.
Periodic ophthalmia, as suggested by the term, comes on at intervals, but eventually after repeated attacks ends in blindness of one or both eyes.
A horse that has had a few attacks, causing a slight opacity of the cornea (scum), is a favorite with the scalper, as he can be bought cheap, treated for the temporary clearing up of the eyes, and sold at a profit to an unwary buyer. The disease is incurable, and its presence is to be suspected when the eyebrow appears triangular and wrinkled, and the eye looks smaller than its mate, or a healthy eye, and is retracted into the orbit.
Unscrupulous buyers sometimes render a horse temporarily blind by chewing whole flaxseed to a pulp and smearing it in the eye. By washing a cloudy, sticky-looking eyeball, this trick is readily discovered.
A horse may also be rendered temporarily blind by the administration of certain drugs.
The clearing-up process of treating a blue-eyed or moon-blind horse also is effected by skilful use of such drugs as atropia, belladonna, eserine, nitrate of mercury ointment, bloodroot, alum, calomel, etc. Their effect is transitory, and the horse soon has an unmistakable attack of ophthalmia.
Examine the Ears.
It will be well to “put a flea in the ear” of the man who contemplates buying a horse and who may not know that the ear will bear investigation. If the animal will not submit to inspection, look out! The horse that will not allow one to handle his ears, or fights when the attempt is made, may be a terror to shoe, and therefore has had the “twitch” put on his ear many a time in the blacksmith’s shop; or he may have had poll-evil, some injury to the ear, or head, or have a disease present which makes the ear sore or sensitive. A horse so affected is difficult to handle, as he fights when the halter or bridle is put on.
Sometimes a fine silken thread may be found running under the forelock from ear to ear to prevent them from lopping over.
Or there may be a leaden bullet suspended by a silk thread in the hollow of the ear to prevent its constant motion. Sometimes the motion indicates impaired sight or nervousness, whereas the lack of it may indicate deafness.