216 Dr. Hosack's Observations on Vision. 
other phenomena occur, by which it may be rendered either 
more general, or liable to objections ? 
I have now finished what was proposed. I have declined 
entering into an extensive view of the structure of the eye, or 
any of the general principles of optics, as those subjects have 
been more ably treated in the works already cited, and thus 
would certainly have destroyed every claim to attention, which 
these few pages in their present , form may possibly possess ; 
and if I should be so fortunate as to succeed in establishing 
the principle I have proposed, for explaining the phenomena 
dependent upon this more important organ of our bcdy (if 
any part possesses a pre-eminence in nature), I also hope it 
may, in abler hands, admit of some practical application, in 
alleviating the diseases to which its delicate organization so 
particularly exposes it * 
* Since the above pages have been written, I have found, upon consulting some of 
the earliest writers, that the effects of the external muscles did not altogether escape 
their attention ; at the same time they had no distinct idea of their action : I must 
therefore disclaim the originality of the thought, although I had never met with it 
before the circumstances already noticed, of the insufficiency of the iris, had suggested 
it. If, however, I have succeeded in pointing out the precise action of those muscles, 
and its application to the general principles of vision, in which, I believe, I have never 
been anticipated, it will be the height of my wishes. 
