On the mechanism of the movements of the iris / by J. N. Langley and H. K. Anderson.

  • John Newport Langley
Date:
[1892]
Catalogue details

Licence: Public Domain Mark

Credit: On the mechanism of the movements of the iris / by J. N. Langley and H. K. Anderson. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    p. 582. Possible connection between the ciliary muscle and the size of the pupil. On the supposed inhibitory action of the sympathetic on the ciliary muscle. p. 584. Experimental proofs of the existence of a radial contractile substance in the iris. 1. Movement of the iris on the side opposite to local dilation. 2. Local dilation of the pupil with simultaneous local contraction of the sphincter. 3. Contraction of a radial strip of the iris. 4. Absence of elasticity from the iris. p. 593. On the supposed inhibitory action of the sympathetic on the sphincter iridis. Attempt to find inhibitory fibres in the third nerve, p. 595. Summary. The cause of the dilation of the pupil, which is produced by stimu- lating the cervical sympathetic, has been a subject of controversy for the last fifty years, and there is perhaps more difference of opinion on the matter now than there was in the time of Budge and Waller. So much has been written on the subject, that it would have been far simpler for us to have confined ourselves to giving an account of the facts which we are able to add to those previously known ; but with a subject of such complexity, we could hardly hope to do much towards the settlement of the controversy without taking into consideration the varied views which have been put forward. We accordingly deal with all the facts and arguments of any importance with which we are acquainted. Ancesthetics used. In all our experiments anaesthetics were used, and primarily chloral for the rabbit, chloroform for the cat, and morphia for the dog; after these had taken effect, a mixture of absolute alcohol chloroform and ether was given at intervals with the inspired air. Theories as to the cause of the dilation of the pupil. In giving a brief summary of the theories which have been, or which might be, put forward with any plausibility to explain the dilation of the pupil, we shall for the present mention those only which deal with dilation produced by stimulating the sympathetic. For this lies at the root of the matter, and the view taken as to the dilation produced in other ways will necessarily depend upon what is shown to be the cause of the sympathetic dilation. The theories to be considered are :—
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