An experimental inquiry into the functions of the ophthalmic ganglion / by C. Radclyffe Hall.

  • Hall, Charles Radclyffe, 1820-1879.
Date:
[1846]
Catalogue details

Licence: Public Domain Mark

Credit: An experimental inquiry into the functions of the ophthalmic ganglion / by C. Radclyffe Hall. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    mulation will sometimes excite movement of tlie eyelid, •which did not occur here. The same want of conducting power in the cx- cito-motory chain which prevented the one action might also have prevented others. 29. The roof of the orbit was then rapidly removed, and the ciliary ganglion and its nerves exposed. Pricking the third nerve, or the ganglion itself, or pinching the fasciculus of ciliary nerves which proceeded from it, caused the previously large and round pupil to become smaller and elliptical; but on ceasing to apply the stimulus the pupil instantly expanded again. I think that the contraction of pupil was most marked when the ciliary neives were irritated. The experiment was repeated on the nerves of the other eye with similar results. As the fifth nerve had previ- ously been divided within the skull {§ 28), this experiment proves that the pupil will both contract and dilate, notwithstanding the fifth nerve is cut through. The proof, however, that the fifth nerve has no control over the action of the iris is not complete, since there might have been sufficient nervous energy left in the nerve-tubes to produce the actions manifested. 30. The other eyeball was removed from the orbit. Its pupil was at first dilated, but in two hours it had become very small. On the following day, it was rather enlarged again. In the eye which was left in its orbit, the pupil gradually diminished to nearly the medium size, and in that state remained until decomposition commenced. The greater contraction of pupil in the removed eye was probably owing in part to mere shrinking ol the tunics from drying ; favouring the rigor mortis contraction of the sphinc- ter iridis. This would occur sooner in the exposed and rapidly cooled eyeball, and therefore whilst the fluids of the eye were in a state better fitted to allow of great contraction of the sphincter than in the more tardily drying unremoved eye. The mequa i y in size of the two pupils illustrates the fact that the ms has a tendency to retain the condition in which it is left when all vita- lity ceases, this tendency being due to the empty or ful state of the vessels of the iris, controlled by the elasticity of its tissu , the time of coagulation of the blood. Experiment Y.—A pigeon. , 31. When both eyes were equally exposed to a strong li0fit, both pupils acted consentaneously. But if the rig it eye was shaded, its pupil dilated singly, the left pupil remaining small. 32. When the sun’s light was concentrated by a powerful lens, and thrown into the pupil, the membrana mctitans swept rapidly across the eye, the eyelids attempted to close, and the pupil of tl a ey<33.mSuddenly'touching any part of the head caused simfiar movement of the nictitating membrane and ms. An emotiona