EYE.

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be compensated by an equivalent depression during some otherperiod of the natural day. Sleep is disturbed and interrupted, inconsequence of the blood-vessels of the brain being irritated by thesudden influx of fresh chyle, by which they are distended ; andrendered, more particularly in the supine posture, liable to rupture.May we not venture, without being accused of entering too farinto theoretical speculations, to attribute, in part at least, to thesecauses, the augmented frequency of apoplexy, and its melancholysequel, palsy ? The palpable increase of which complaints in thiscountry of late years is a subject of serious alarm.' A. P. B.

CHAP. XXXIX.DISORDER OF THE SENSES.

We do not mean to treat of the nature of our sensations, or togive a minute description of the various organs by which they areperformed ; but to point out some of the diseases to which theseorgans are more liable, and to show how they may be preventedor remedied.

Of the Eye.

No organ of the body is subject to more diseases than the eye ;nor is there any one of which the diseases are more difficult tocure. Though more ignorant persons pretend to cure these thanany other class of diseases, yet a very superficial acquaintance withthe structure of the eye, and the nature of vision, will be sufficientto convince any one of the danger of trusting to them. These dis-eases often exceed the skill of the most learned physician ; hencewe may easily infer the danger of trusting them to ignorant quacks,who, without all peradventure, put out more eyes than they cure.But, though the diseases of the eye can seldom be cured, theymight often, by due care, be prevented ; and, even where the sightis totally lost, many things might he done, which are generally neg-lected, to render the unhappy person both more useful to himselfand to society.*

The eyes are hurt by viewing bright or luminous objects; keep-ing the head too long in a hanging posture; violent head-achs ;excessive venery ; the long use of bitters ; the effluvia from acridor volatile substances ; various diseases, as the smallpox, measles,&c. ; but, above all, from uight-wafchíng, and candlelight-studies.Long fasting is likewise hurtful to the eyes, and frequent heats andcolds are no less pernicious. The eyes are often hurt by the stop-page of customary evacuations ; as morning sweats ; sweating ofthe feet; the menses in women ; and the bleediug piles in men.

* There are many employments of which blind persons are very capable, as knitting,carding, turning a wheel, teaching languages, &c. Nor are instances wanting of per-sons who have arrived at the highest pitch of learning, without having the least idea ofeight. Witness the late famous Nicholas Sanderson of Cambridge, and my worthyfriend, Dr. Thomas Blacklock of Edinburgh. The former was one of the first mathematicians of his age, and the latter, besides being a good poet and philosopher, waamaster of all the learned languages, and a very considerable adept in the liberal arts.