254 DE. HUBEET AIEY ON A DISTINCT EOEM OE TEANSIENT HEMIOESIA. 
inconvenience after these attacks, and my vision, although I have at times tried my eyes 
severely with optical experiments, is I believe as good as ever, though I have been sub- 
ject occasionally to this affection for more than twenty years. The only difference be- 
tween the phenomena as they appear to me and as they are described by Dr. Airy is, 
that in my case they are always unaccompanied with colour”*. 
This case, though clearly belonging to the later group (p. 248), yet in absence of colour 
shows a step towards the earlier, and suggests that all the forms of transient hemiopsia 
are but varieties of one and the same affection, differing only in degree of prominence 
of their different features. We must look for more connecting links before we can be 
satisfied that it is so. 
* 
Hitherto I have quoted only from non-medical authorities, and I think no one can 
fail to be struck by the amount of attention that this obscure malady has received from 
so many writers of such high scientific attainments. 
Most medical works that I have consulted give but little information concerning 
Transient Hemiopsia. The fullest notice of the subject that I have met with is in 
Tyrrell’s 4 Diseases of the Eye’ (vol. ii. p. 231), under the head of “ Functional Amau- 
rosis from Cerebral Disturbance.” 
But very lately (April 7, 1870) my attention has been drawn to two passages in the 
writings of earlier authors in which the disease in question is plainly to be recognized. 
The first is to be found in the works of Dr. Fothergill, “ Remarks on the Sick Headach” 
(a paper read before the Select Society of Licentiates, Dec. 14, 1778). Speaking of 
butter as an article of diet, he says, “ Nothing more speedily and effectually gives the 
sick-headacli, and sometimes within a very few hours. After breakfast, if much toast 
and butter has been used, it begins with a singular kind of glimmering in the sight ; 
objects swiftly changing their apparent position, surrounded with luminous angles, like 
those of a fortification. Giddiness comes on, headach, and sickness. An emetic, and 
warm water soon wash off the offending matter, and remove these disorders.” 
The other passage to which I refer occurs at pages 557, 558 of the first volume 
of ‘ Collections from the unpublished medical writings of the late Caleb Hillier Parry, 
of Bath, 1825.’ 
“ After violent fatigue, more especially when accompanied with fasting eight or ten 
hours, which has often happened to me, and now, Sept. 26, 1808, I have frequently 
experienced a sudden failure of sight. The general sight did not appear affected ; but 
when I looked at any particular object, it seemed as if something brown, and more or 
less opake, was interposed between my eyes and it, so that I saw it indistinctly or some- 
times not at all. Most generally it seemed to be exactly in the middle of the object, 
while what my sight comprehended all round it, was as distinct and clear as usual, in 
* Sir Chakies Wheatstone had seen my description before the paper was finally presented. 
