422 Original Articles. | July, 
ON THE HISTORY AND USES OF THE 
OPHTHALMOSCOPE. 
By Tuomas Nunnery, F.R.C.8.E., &e. 
THoucH the present age may not be so distinguished for any very 
brilliant discovery or startling scientific invention as were some of 
those which are gone by, it may be doubted if there has ever been a 
period in the world’s history in which work likely to advance know- 
ledge and benefit mankind was more heartily, honestly, or generally 
pursued than at the present day. If the rewards have not been so 
ereat to one or two individuals as to overshadow and obscure the 
eleanings of all the other labourers, the progress made in precise 
knowledge and the adoption of scientific precision has certainly never 
been more marked. The result is a steady progress, even in those 
departments of knowledge which heretofore have been considered as 
rather speculative than positive, or as belonging more to art than to 
science. The known laws of one branch of science have not unfre- 
quently been applied with great ingenuity and success to the prac- 
tical elucidation of obscure phenomena in other departments. Of 
this-advance the instrument, the name of which is placed above, and 
the employment of which has recently been introduced into the inves- 
tigation of diseases of the eye, affords a very good illustration. In 
drawing attention to it, we do not intend to enter upon a detailed criti- 
cism of the various appearances, and the minute shades of difference 
which the ophthalmoscope reveals, inasmuch as the subject, techni- 
cally treated, belongs to the domain of pure medicine, and would be 
neither interesting to, nor be understood by, the general reader. 
Indeed, it is very possible that many persons have not as yet heard of 
the ophthalmoscope by name, and very certain that of those who have, 
many more have but little knowledge of its application. Indeed, so 
novel is the instrument, and so recondite are its revelations, that we 
might say, as yet, it has been very partially employed by only one 
section of the medical profession. Doubtless the time will soon arrive 
when more will have been learnt by those who now use the instrument, 
and its employment be more widely distributed. 
We propose rather, as briefly as possible consistent with intel- 
ligibility, to give such an account of the instrument itself, the 
principles upon which its action is founded, and the objects which 
its use is likely to reveal, as may be sufficient to keep the general 
reader aw courant with the scientific inventions of the day, even though 
such inventions may belong exclusively, in the first imstance, to 
one section of the community: we say in the first instance, for, 
without doubt, in the long run every improvement in the means 
of diagnosing and rendering clear and indubitable, diseases, in what- 
ever part of our bodies they may be seated, which heretofore have 
been most obscure and dubious, is of permanent interest to every 
person. This is especially the case with diseases of the eye, the 
