63 
Br Gillies on a peculiar modification of Vision. 
tion of my eyes, which inclined me to ascribe these uneasy sen- 
sations to my having overstrained them, and to paying more 
particular attention to my sensations at the time than on other 
occasions. In general, indeed, I suffered little inconvenience 
from it, with the exception of its unfitting me, during its conti- 
nuance, for any serious occupation, where my vision was re- 
quired. 
While under the infiuence of this affection, my eyes were re- 
peatedly examined by various professional gentlemen, none of 
whom could perceive the slightest deviation from the natural ap- 
pearance of these organs, or any apparent alteration in the con- 
vexity of the cornea. Among these I may be allowed to men- 
tion the names of Dr Farre of London, and of my much re- 
spected friend and preceptor, the late Dr Gordon, whose merits 
as an acute and intelligent physiologist and anatomist, as well as 
his private worth, will long endear his memory to every one 
who had the advantage of knowing him, or of listening to his in- 
structions. 
These remarks constitute the very hmited and imperfect ob- 
servations which I have been able to make on these occasions. 
Such as they are they may be relied upon, being the result of 
actual observation ; and with some, perhaps, will be considered 
the more worthy of attention, as I have no particular theory to 
support, — a source of fallacy which cannot be too much guarded 
against, in making observations on one’s own sensations. 
As I have been unable to bring forward any satisfactory ex- 
planation of these phenomena, I have altogether refrained from 
giving any opinion on the subject, but presume that it may be 
dependent on some modification of the adapting power of the 
eye to near and to distant objects. 
These obser^^ations, however, seem to lead to the following 
conclusions : 
1^^, That this modification of vision always made its appear- 
ance in a gradual manner, proceeding progressively, and almost 
imperceptibly, from one degree to another, till it had reached 
its maximum ; and constantly disappeared in the same gradual 
and progressive manner, but in a reversed order. 
2d, There was no apparent diminution in the distinctness or 
clearness of surrounding objects, further than might have been 
