. On the anomalies of accommodation and refraction of the eye, witha preliminary essay on physiological dioptrics. Fig. 102. 200 MODIFICATION OF THE ACUTENESS OF VISION. the lens, numerous in the vitreous humours of old persons, corresponding tothose described under d. 3. The spectrum of the crystalline lens.—For observing this, more per-fectly homocentric light, and therefore a very small opening, is whole circle is then less illuminated, and covered, as it were, with acrape Fig. 103, my right crystalline lens in mydriasis). We find here : a. Fig. 103. Pearl-spots, tolerably rou
. On the anomalies of accommodation and refraction of the eye, witha preliminary essay on physiological dioptrics. Fig. 102. 200 MODIFICATION OF THE ACUTENESS OF VISION. the lens, numerous in the vitreous humours of old persons, corresponding tothose described under d. 3. The spectrum of the crystalline lens.—For observing this, more per-fectly homocentric light, and therefore a very small opening, is whole circle is then less illuminated, and covered, as it were, with acrape Fig. 103, my right crystalline lens in mydriasis). We find here : a. Fig. 103. Pearl-spots, tolerably round disks with accurately circumscribed darkermargins, but brighter internally, nearly universally occurring in every eye ;the majority are situated tolerably close to the surface of the crystalline lens,in great part eccentrically placed, and therefore appearing only when thepupil is artificially dilated. Examining at different times, I on each occasionfound others; they may be developed in a few days, and sometimes continue ayear or longer; in general their number increases with the advance of are microscopically visible as large globules among the superficial fibresof the lens, which they, as it were, push out from one another, b. Black, orrather opaque spots, usually round, but sometimes of irregularly angular, or SPECTRUM OF THE CRYSTALLINE LENS. 201 oblong form, not so common as the pearl-spots. I have also seen them, onmicroscopic examination, rather superficially, as white, granular, opaque cor-puscles, almost always in the boundaries of the
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