Inflammation of the conjunctiva occurs in many individuals during very warm and sunny weather. At such a period, the eye is often excited by reflection of intense light from the surface of the earth; and is irritated by sudden exposure to a degree of light to which it has not been previously accustomed. Different directions of the sun’s rays, and different kinds of light, seem to exert different influences on the organ. The rays are most hurtful when they do not fall in a perpendicular direction on the eye, but slopingly or horizontally. Strong light from the moon, and light reflected from scarlet, are also particularly injurious. Undue exertion of the eye weakens it, and renders it prone to become inflamed. The eyes of infants are often violently inflamed, in consequence of imprudent exposure to light before they have been gradually accustomed to its stimulus. Again, inflammation is caused by imprudent exposure of the eye directly to cold, or by exposure of other parts causing suppression of their discharges, whether natural or not. Inflammation of the conjunctiva often follows suppression, however occasioned, of the menstrual or hemorrhoidal discharges, as also suppression of discharges from the urethra, from the Schneiderian membrane, or from behind the ears. Irritations in the neighbouring parts, as in the mouth during dentition, may also excite the disease. Immediate irritations, however, are the most frequent cause, as the lodgement of extraneous bodies on the surface of the organ—particles of sand, dust, snuff, pepper, or gunpowder, minute insects, loose or inverted eyelashes. By the presence of such substances, the eye is often kept in a very irritated state for a long period. The most violent conjunctival inflammation is sometimes produced by contact of gonorrhœal matter through carelessness. Occasionally metastasis of inflammation takes place from one eye to another; so that a person may be seen one day with severe inflammation of the right, and on the following day with a similar affection of the left, and the right entirely free from disease. Another cause, sometimes met with, of inflammatory action in the conjunctiva, is the lodgement of large foreign bodies in the orbit, with or without destruction of the eye; as splinters of wood, straws, rusty iron nails, sharp portions of stone, &c., penetrating the globe of the eye, or parts in the immediate neighbourhood. Upon removal of the cause, the redness, discharge of tears, pain, &c., sometimes subside without inflammation having been established, the vessels of the part regaining their contractility; but if the cause is continued for any considerable time the effects do not rapidly abate. Wounds and other injuries of the organ are generally followed by inflammation. But a simple clean wound or puncture made with a fine instrument, as in many operations, and in a favourable constitution, frequently produces little or no excitement of the part.