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sight in relation to the aforementioned deviations Ironi tlie normal in the shape of the eyeball have been adv;uiced aiul defendeil." 'Dirsc bri.lr Rclloxo. Imr. bi. I) iind c. siiid sclir viel licht- sch«;ichtr .lis dcr Reflex dcr Hornliaut, «, Der von der vordercn Unsciill:iclie. 1). biltlcl ein aufrcclits(cliende9 Bildchcn der Flarame, ctwaa grosser als das von dcr Ilornliaut cntworfcne. aber mcist so vcrwascllen dass man die Geslalt der Flamnic nicbt gcnau crkennen Kann, Hantlbuch dcr Plwiiologischcn Oftik. p. iji. By some the muscles of the eye were believed to play a part in accommodation. Of this theory Donders says : Cost Cialis Daily Use "Before physiologists were acquainted with the changes of the dioptric Cost Cialis Daily Use system they often attached importance to the external muscles in the production of accommodation. Now that we know that ac- commodation depends on a change of form in the lens this opinion seems scarcely to need refutation." {The Anomalies of Accommodation attd Refraction of the Eye, p. 22.) According to other theories, accommodation is effected by a change in the curvature of the cornea ; by a change in the position of the lens ; by the con- traction of the pupil; through the agency of the iris and so on. Almost every imaginable hypoth- esis has apparently been advanced to account for the phenomenon, some of the guesses being so wild that Donders refused even to refer to them, consid- ering they would detract from the scientific char- acter of his work. My own e.vijeriments, carried on during the last five years in the Physiological Lalx)ratory of the College of Physicians and Surgeons, Columbia University, New York, and at the New York City Aquarium, demonstrate that the lens is not a factor in acconmiodation, but that the change of focus necessary for [x-rfect vision at different dis- tances is etfected by a change in the length of the Cost Cialis Daily Use eyeball, brought about by the action of the muscles on the outside of the globe. In the earlier of these experiments, the results of which were published in the New York MEDic.\r. Journal of May 8, 1915, it was found that Cost Cialis Daily Use accommodation, as measured by tlie objective test of simultaneous retinoscopy, oc- curred in all normal eyes of dogs, rabbits, and fish after the removal of the lens, and that it never oc- curred after one or both of the oblique muscles had been cut across and the insertion of the muscle to the fascia completely separated. It was also found that any form of refractive error could be produced in the normal eyes of these animals by manipulation of the outside muscles of the eyeball, indicating that liiese conditions are not due to pemianent deforma- tions in the shape of the eyeball, as generallv l)e- licved. By normal eyes is meant those in which, in addi- tion to other conditions of a healthy stnicture, both oblique muscles are present and active. In some animals it was found that one oblique muscle was absent or rudimentary. This was true in the case of all cats, and accommodation could never be prc^- duced in these animals by stimulation with electric- ity. Even in cats, however, when the rudimentary oblique muscle was strengthened by advancement, accommodation was always produced by stimulation of the eyeball, or of the third or fourth nerves, near their origin in the brain, the fourth ner\'e, contrarj* to ]irevious belief, 'x'ing just as much Cost Cialis Daily Use a nerve of ac- commodation as the third. .■\fter the results of these experiments were pub- lished it was suggested to me by Dr. Frederic S. Lee that it would W well lor Cost Cialis Daily Use me to repeat the cxjXTi- nients of ilclmholtz, making a thorough investiga- tion of accommodation from a study of the images reflected from tlie front of the cnistalline lens and other parts of the eyeball. This work was under- Cost Cialis Daily Use 9it HATES: IMAGES REFLECTED FROM CURXFA. IRIS, LEXS, AND SCLERA. [New York Medical Journal. taken some four years ago. For a year or more 1 was unable to obtain an image from the front of the lens which was sufficiently clear or distinct to be measured. It was much blurred, and because of this lack of distinctness, it was impossible to tell whether it became smaller or larger during accommodation. \^'ith a diaphragiTi 1 got a clearer image, but it still was not sufficiently clear to be measured. To Helm- holtz the indistinct image of the naked candle seemed to show an appreciable change, while the 1. — Adjustments tor ubtaillilig images on the le front of the sclera. T, table; C, camera; L, light, looo watts; D, diaphragm; Cm, concave mirror; Cr, condenser; R, stand for chin rest; F, stand for forehead rest; E, eye. images obtained by the aid of a diaphragm showed it more clearly; but I was unable, either with a diaphragm or without it, to obtain images which I considered sufficiently distinct to be reliable. Men who liad been teaching and Cost Cialis Daily Use demonstrating Helm- holtz's theory repeated his experiments for my benefit, but the images which they obtained on the front of the lens did not seem to me to be any better than Cost Cialis Daily Use my own. After a year or more of Cost Cialis Daily Use failure I began work at the Aquarium on the eyes of fishes. It was a long story of failure. Finally, I became Cost Cialis Daily Use able, with the aid of a strong light — i.ooo watts — a diaphragm with a small opening, and a condenser, to Cost Cialis Daily Use obtain, after some difficulty, a clear and distinct image from the cornea of fish. This image was sufificiently distinct to be measured, and after many months a satisfactory photograph was obtained. Then the work was resumed at the Physiological Laboratory on the eyes of human beings. By means of nearly the same tcchnic an image was obtained on the