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CHAP. XLIV.
DISORDERS OF THE SENSES.
WE de n t mean to treat of the nature of our sensations, or to give aminute description of the various organs hy which they are performed;hut to point out some of the diseases to which these organs are mostliable, and to shew how they mav he prevented or remedied.
OF THE EYE.
No organ of the body is subject to more diseases than the eye, nor isthere any one of which the diseases are more difficult to cure. Thoughmore ignorant persons pretend to cure these than any other class of dis-eases, yet a very superficial acquaintance with the structure of the eyeand nature of vision will be sufficient to convince any one of the dangerof trusting to them. These diseases often exceed the skill of the mostlearned physician; hence we may easily infer the danger of trustingthem to ignorant quacks, who, without all peradventure, put out moreeyes than they cure. But, though the diseases of the eye can seldombe cured, they might often, by due care, be prevented; and, even wherethe sight is totally lost, many things might be done which are. generallyneglected, to render the unhappy person both more useful to himseHand to society.
It is a pity those who havetne misfortune to be born blind, or wholose their sight when young, should be suffered to remain in ignoranceor to beg. This is both cruelty and want of economy. There are manyemployments of which blind persons are very capable, as knitting, card-ing, turning a weel, teaching languages, &c. Nor are instances wantingof persons who. have arrived at the highest pitch of learning, withouthaving the least idea of light. Witness the late famous Nicholas Sander-son of Cambridge, and the late excellent poet Dr. Thomas Blacklock ofEdinburgh. The former was one of the first mathematicians of his age,and the latter, besides being a good poet and philosopher, was master ofall the learned languages, and a very considerable adept in the liberal arts.
The eyes are hurt by viewing bright or luminous objects; keeping thehead too long in a hanging posture; violent head-achs; excessive venery;the long use of bitters; the effluvia from acrid or volatile substances ;various diseases; as the small-pox, measles, &c. but, above all, fromnight-watching, and candle-light studies. Long fasting is likewise hurt-ful to the eyes, and frequent heats and colds are no less pernicious.The eyes are often hurt by the stoppage of customary evacuations; asmorning sweats; sweating of the feet; the menses in women ; and thebleeding piles in men. All kinds of excess are likewise hurtful to thesight, particularly the immoderate use of ardent spirits and other strongliquors.