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

  • Hall, Charles Radclyffe, 1820-1879.
Date:
[1846]
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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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    been able to satisfy myself that abduction of the eye in the rab- bit is invariably accompanied by contraction of the pupil. Is there a motor nerve for causing dilatation of the pupil ?— That the fifth nerve supplies no motor filaments for the dilatation of the pupil is proved by the experiments detailed. It has been conjectured that filaments proceed from the first cervico-spinal nerve, which, after passing through the superior cervical ganglion, become united with the sixth cerebral nerve, and ultimately reach the iris, over the dilating movement of which they preside. In support of this view, the principal facts adduced are, the contrac- tion of the pupil, which results from removal of the superior cer- vical ganglion ; the dilatation asserted to take place when that ganglion is irritated ; and the following experiment of Guarini, “ who having extirpated the superior cervical ganglion of an ani- mal, and thus produced contraction of the pupil, administered a poisonous dose of strychnine (the effect of which generally is to dilate the pupil.) The pupil of the side operated on dilated but little, for the filaments of the third nerve now unopposed, main- tained its contraction, whilst the pupil on the opposite side was enormously dilated, probably because of the radiated muscle (?) be- ing put strongly into action by the stimulating effects of the strychnine on the spinal cord and so on the nerve (i. e. the cer- vical filaments inclosed with the sixth nerve) supplying this mus- cle.”* Did the pupil dilate in obedience to a certain nerve, sec- tion of this nerve might cause momentary dilatation, just as we have seen that section of its contracting nerve causes momentary contraction ; but on the subsidence of this effect of the immedi- ate injury, we should expect all power of active dilatation, at least so far as the divided nerve was concerned, to be abolished. ^ We should expect not that the pupil would dilate “ but little, but that it would not dilate at all. Dr John Reid’s experiments-]-are opposed to the assertion that irritation of the superior cervical aamdion causes dilatation of the pupil. In one experiment, on removing the lower half of the superior cervical ganglion in a dog, the pupil immediately contracted (Exp. III.) *n a kitten, “ when the sympathetic was compressed with a moderate force, the right pupil began to contract gradually, and became much smaller than that of the left eye ; and it again resumed its for- mer size on removing the pressure (Exp. IV.). If the compres- sion in the latter experiment be considered to have paralyzed the assumed nerve of dilatation as it passed through the ganglion, the partial removal of the ganglion in the former must certainly have proved a mode of irritating any filaments connected with the on- removed portion of the ganglion. Yet, the effect on the pupil * Nanking's Abstract, vol. ii.p. 310. -1- Edinburgh Med. and Surg. Journal, No. 14.