This disease consists in entire or partial loss of vision in consequence of paralysis of the optic nerve, or interruption of its communication with the brain. Injuries of the head, or ball of the eye, or some disease of the brain, are the usual causes. The dog walks cautiously, head elevated, the eye has a peculiar glassy appearance, and the pupil does not dilate and contract when light is brought near or removed from the eye. But little can be done for these cases. In the earlier stages a dose of the A.A., may possibly arrest its progress, but generally it is incurable in man or beast. Cataract Opacity of the crystalline lens, or of its capsule, or both, prevents the transmission of light, and thus causes blindness. One or both eyes may be affected; old dogs generally suffer in both. The causes are the same as those which lead to cataract in the horse; and to the section thereon reference should be made. But little can be done by way of medicine; A.A., will sometimes relieve. Pterygium This disease, which consists in a thickened state of the cellular tissue of the conjunctiva, extending from the inner angle of the eye towards the cornea, is not uncommon in dogs, both old and young. In pups it is often cured by the mother’s licking the eye; in old dogs it proves intractable. It sometimes follows ophthalmia. TREATMENT.—You may give daily a dose, one to three drops, of A.A., with decided benefit. Eczema of the Eyelids In this affection small pustules appear on the edges of the lids at the roots of the lashes; presently they break, emit matter, which drys into crusts, mats the hair, and glues the lids together. If not arrested, the ulceration extends and destroys the bulbs of the hair, and with them the eyelashes. TREATMENT.—The eyelashes should be clipped off close to the eyelids; the parts carefully washed with a sponge and diluted HUMPHREYS’ MARVEL WITCH HAZEL, morning and night, to prevent agglutination. When crusts have formed they can be best softened and removed by fomentations with warm water. Care should be taken not to drag away the purulent matter with force. Give I.I., morning and night. Fistula Lachrymalis The Lachrymal canals, which originate from the internal angle of the eye, convey the tears into the lachrymal sac, an oval bag, which is a receptacle for tears. It is situated near the angle, and constitutes the upper extremity of the nasal duct. If this duct be obstructed, the tears flow over on the cheek and a small tumor forms in the sac. This is followed by inflammation, suppuration, and the formation of an abscess, which bursts externally and leaves a fistulous opening, through which tears flow from the sac on to the cheek. TREATMENT.—Sponge the eye with warm water, and give A.A., morning and night, if the eye or lids are inflamed, or the I.I., if no manifest inflammation is present.