OBSERVATIONS ON VISION.

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tliesc processes are yet more incapable ofdrawing back tlie crystalline, and such anaction is equally inconsistent with observa-tion.

Some other suppositions have also beenformed by different physiologists. Zinn ima-gines the ciliary processes to be distended bya fluid, and to protrude the lens. Sauvagesconjectures, that the ring of Petit is inflatedby the electric fluid, and alters the form ofthe lens: Moulin, that the cornea is renderedmore convex by its ligaments, which are infact nerves: Bourdelot, that the contractionof the pupil increases the convexity of thelens. But all these opinions are liable to asstrong objections as those which I have al-ready examined.

Prom these considerations, and from theobservations of Dr. Porterfield and others,that those who have been couched haveno longer the power of accommodating theeye to different distances, l had concludedthat the rays of light, emitted by objects at asmall distance, could only he brought to focion the retina by a nearer approach of thecrystalline to a spherical form ; and I couldimagine no other jporver capable of produc-ing this change than a muscularity' of a part,or the whole, of its capsule.

But in closely examining, with the nakedeye, in a strong light, the crystalline from anox, turned out of its capsule, 1 discovered astructure, which appears to remove all thedifficulties with which this branch of opticshas long been obscured. On viewing it witha magnifier, this structure became more evi-dent.

The crystalline lens of the ox is an orbicu-lar, convex', transparent body, composed ofa considerable number of similar coats, ofwhich the exterior closely adhere to the inte-

rior. Each of these coats consists of six seriesof tibres, intermixed with a gelatinous sub-stance, and attached to six lines, which havesomewhat of a membranous appearance.Three of these lines or tendons are anterior,three posterior ; their length is about twothirds of the semidiameter of the coat; theirarrangement is that of three equal and equi-distant rays, meeting in the axis of the crys-talline ; one of the anterior is directed to-wards the outer angle of the eye, and one of-the posterior towards the inner angle, so thatthe posterior are placed opposite to the middleof the interstices of the anterior; and planespassing through each of the six, and throughthe axis, would markon either surface six re-gular equidistant rays. The fibres arise fromboth sides of each line; they diverge tillthey reach the greatest circumference of thecoat, and having passed it, they again con-verge, till they arc attached respectively tothe sides of the nearest lines of the oppositesurface. The anterior or posterior portion ofthe six, viewed together, exhibits the appear-ance of three penniformiradiated muscles.The anterior lines of attachment of all thecoats are situated inthesame planes, and theposterior ones in the continuations of theseplanes beyond the axis. Such an arrange-ment of fibres can be accounted for on noother supposition than that of muscularity.'This mass is inclosed in a strong membranouscapsule,to which it is loosely connected by mi-nute vessels and nerves; and the connexion,is more observable near its greatest circum-ference. Between the mass and its capsule isfound a considerable quantity of an aqueousfluid, the liquid of the crystalline.

1 conceive, therefore, that when the willis exerted to view an object at a small dis-tance, the influence of the mind is conveyed