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XIV.—Of the Fourth and Sixth Nerves of the Brain;—being the concluding paper on the distinctions of the Nerves of the Encephalon and Spinal Marrow

Published online by Cambridge University Press:  17 January 2013

Extract

Interesting as theoptical properties of the eye have been to philosophers in every age, there are conditions of this organ which are no less curious, and which have not had their share of attention.

In the year 1823, I introduced the subject to the Royal Society of London, nearly in the terms I am now using, but there is much more in the subject than I then conceived, although I see no reason to change the mode of contemplating it.

The eight muscles of the eye, and the five nerves, exclusive of the optic nerve, which pass to them, imply the complex nature of the apparatus exterior to the globe, and I fear it is too plain that the subject has not been satisfactorily treated.

It is chiefly with respect to the protecting motions of the eye that the difficulty occurs, for I hope the dependence of the proper organ of vision on the voluntary muscles of the eye, has been proved and acknowledged.

Permit me to draw the attention of the Society to what appears a very simple piece of anatomy, the circular muscle which closes the eyelids, orbicularis palpebrarum.

Type
Transactions
Copyright
Copyright © Royal Society of Edinburgh 1839

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References

page 240 note * Where there is a retractor muscle, this abducens nerve supplies it, which strengthens the supposition of a relation between the retraction of the eye and its simultaneous direction inwards.

page 240 note † Taking the facts of the anatomy into account, and the actions of these muscles, the subject becomes of great interest, as connected with the expression in the eye.

page 241 note * The discovery of this fact has been caught at by men, as incapable of the induction which led to it, as of following it up in its consequences.