DR. HUBERT AIRY ON A DISTINCT EORM OF TRANSIENT HEMIOPSIA. 255 
consequence of which, if I wished to see anything, I was obliged to look on one side. 
At other times, though much more rarely, the cloud was on one side of the direct line 
of vision. After it had continued a few minutes, the upper or lower edge, I think 
always the upper, appeared bounded by an edging of light of a zigzag shape, and corus- 
cating nearly at right angles to its length. The coruscation always seemed to be in one 
eye ; but both it and the cloud existed equally, whether I looked at an object with one 
or both eyes open. When I shut both eyes, covering them with my hand so as to ex- 
clude all rays of light, the coruscation was still perceptible in the same place, and what 
had been a semi-opake cloud appeared lighter than the rest. When I raised or lowered 
the axes of my eyes, or squinted, the cloud and coruscation, though it moved its 
place, still bore the same relation to the object at which I looked. In this way they 
would remain from twenty minutes sometimes to half an hour, the cloud lessening as 
the coruscation continued, and the latter sometimes rather suddenly going off'. They 
were in me never followed by headach, but seemed evidently connected with the state 
of the stomach; for though they sometimes occurred without any feeling of indisposi- 
tion at the time, either there or elsewhere, they generally went off with a movement in 
the stomach, producing eructation ; and anything which produced a glow in the stomach, 
with eructation, and perhaps without it, such as brandy, hot water, &c., always hasten 
their departure.” 
My own experience of Hemiopsia dates from 1854. I was so much struck by the 
first attack that I made a record of it at the time, which I allow myself to transcribe 
here as an authentic and independent, though very incomplete, account. 
“Friday, Oct. 6th. — This morning (the last before the Michaelmas Holidays) I had 
an attack of that half-blindness to which is subject; she had one yesterday. It 
came on while I was with Mr. Dkew*, and I noticed it first by being unable to see the 
‘ t ’ in “ tan A” when I looked at the top. At first it looked just like the spot which you 
see after having looked at the sun or some bright object; I thought it might be an eye- 
lash in the way, or something of that sort, but I was soon undeceived when it began to 
increase. I then bethought me that it must be the same thing that suffered from, 
so I let it alone, knowing that it would go off in time, which it did, leaving a most 
terrible headache behind it, which is the worst part of it, the blindness itself giving no 
pain whatever. \\ hen it was in its height it seemed like a fortified town with bastions 
all round it, these bastions being coloured most gorgeously. If I put my pen into the 
space where there was this dimness, 1 could not see it at all, I could not even distinguish 
tne colour of the ink at the end. All the interior of the fortification, so to speak, was 
boiling and rolling about in a most wonderful manner as if it was some thick liquid all 
alive. It did not belong only to one eye, but to both, the right eye having the most.” 
INow Professor of Mathematics at King’s College, London, formerly Yice-Principal of the Blackheath 
Proprietary School. 
2 L 2 
