A synopsis of the diseases of the eye, and their treatment : to which are prefixed a short anatomical description and a sketch of the physiology of that organ / by Benjamin Travers ; with notes and additions by Edward Delafield.

  • Benjamin Travers
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: A synopsis of the diseases of the eye, and their treatment : to which are prefixed a short anatomical description and a sketch of the physiology of that organ / by Benjamin Travers ; with notes and additions by Edward Delafield. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

    97/526
    cesses. to distance are to be explained. And this forms no objection to the hypothesis; because it is only in the voluntary and steadily preserved contrac- tion of the pupil that the latter object is or can be required ; for blindness would as surely en- sue from gazing on the sun, as death from sus- pending the actions of the respiratory muscles, were it in our power to do either; and there- fore the involuntary has the ascendancy over the voluntary action in both these cases, as it hae in all cases of mixed muscles. Radiated fibres are described by Zinn and uveal pro- longatioos Haller as raised on the posterior face of the iris, °^hper£u' and advancing even to the margin of the pupil. They are distinct from those seen upon its an- terior surface, and regarded as continuations of the ciliary] processes. In man no such fibres are distinguishable by the naked eye ; but if the observation, however obtained, be correct, it affords a strong presumption in favour of the power of the iris to change the figure of the lens by the instrumentality of the plicae. The cap- sule, it is true, is fixed by the processes, but this opposes no impediment to the change sup- posed ; for the membrane cf Petit, to whicli alone the processes are affixed, is relaxed when they are closed, and extended when they are separated, and thus permits the capsule to yield only in the degree required for the change of figure of the lens; or. in other words. f>re-