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Snow-Blindness and Effects of

eyes, cold, exposure, light, loss, attended and becoming

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SNOW-BLINDNESS AND EFFECTS OF COLD.—Evervone is familiar with the primary stimulating and invigorating effect of cold, and how, under the influence of the stimulus, the eves become brighter, the cheeks reddened, the pulse-rate increased, and a general sense of mental exhilaration and well-being is created. Let, however, the cold be sufficiently intense and the exposure sufficiently long, and symptoms of depression soon manifest themselves, by pallor, difficulty of breathing, drowsiness, coma and death.

The predisposing causes to frost-bite, chilblains, and the ill effects of cold in general are, intemperance in the use of alcohol, inanition, improper or insufficient food, occupations which involve prolonged exposure without the exercise necessary to maintain the circulation, etc. Of constitutional causes, the lymphatic temperament predisposes to frost-bite and chilblains.

Snow-Blindness.—Trappers, prospectors, lumbermen, and others who are exposed to the intense glare of the sun and strong reflected light from the snow in northern latitudes, frequently suffer from a peculiar affection of the eyes called snow-blindness. It usually manifests itself quite suddenly by swelling and redness of the eyelids (cheozosis), redness of the conjunctiva, profuse flow of tears, extreme sensitiveness to light, and a gradual loss of sight. This loss of sight is due to haziness of the cornea, and to a loss of colour perception. The snow-blind individual is blind only in the sense that he perceives white light, and dimly the forms of objects. March is the month in which snow-blindness is most likely to occur, because of the greater power of the sun, and because the system is more or less debilitated by a long winter and the want of fresh vegetables. It is particularly common in Alaska and the north-west provinces of Canada.

To prevent snow-blindness the eyes must be protected by goggles. From time immemorial the Esquimaux have worn wooden goggles to protect the eyes from the glare. They are made of thin pieces of carved wood, pro vided with slits which enable the wearer to see. They are usually blackened on the inside, and some are provided with a sort of peak to give additional shade (see Figs. 391 A and B) . Smoke-coloured glasses are to be recom

mended, although they do not serve the purpose as well as do the wooden shields. The absence of a peak greatly lessens their usefulness, demon strating that the direct rays play a more important part than the reflected rays in producing snow-blindness. The use of lime-juice is likewise impor tant, as observations have demonstrated that the absence of vegetable food and acids plays an important role in the production of snow-blindness.

Relief from the local pain and discomfort can be obtained by bathing the eyes in a solution of equal parts of distilled extract of witch-hazel and warm water ; or in an infusion of poppy-heads, made by breaking up four poppy heads, placing them in a covered vessel, steeping for ten minutes in a pint of boiling water, and straining. Other forms of treatment, with weak solutions of cocaine or atropine, should be left to the physician, as these drugs may do incalculable injury if used incautiously. If the patient is greatly debilitated, a moderate amount of stimulant should be given, especially in the form of port wine negus or egg-nogg.

Persons who have suffered from snow-blindness are much more liable to subsequent attacks than others, if great care is not exercised. The acute ness of vision may remain impaired for a long time, even for years, and the eyes are easily fatigued when used for near work.

Chilblains.—The mildest form of ill effect from exposure to cold is called chilblain. It is particularly liable to affect young girls of a lym phatic or strumous temperament, and manifests itself on approaching a hot fire or entering a warm room after exposure to cold. The hands or feet at first look very pale, and then an eruption of violet or chill-red patches appears. These patches are slightly raised above the surrounding surface, are irregular in shape, and are attended by severe itching and burning. Vesicles form, which, on becoming eroded, develop into sluggish ulcers with white edges, attended by a slimy discharge. Cracks and fissures which are very painful and difficult to cure, may also form, often becoming chronic, or recurring on slight exposure.

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