458 RESEARCHES INTO THE CAUSES OF BLINDNESS. 
the northern side are two wings, the eastern one forming a 
stable for twenty-eight horses. 
We would call the attention of our readers to the position of 
this stable. Not far from this quarter, which usually lodges 
two squadrons, flows the little river of La Rossette, which is chiefly 
supplied with water from neighbouring ponds. During the summer, 
especially when the weather is alternately hot and moist, at sun- 
set thick white foggy vapours may be seen rising from the banks 
of this stream, which gradually increase and extend themselves 
until they may almost be said to resemble a moving mountain, 
impenetrable to the eye, and coming closely in contact with the 
northern range of stabling. 
During the summer of 1841, which was, as most persons will 
recollect, alternately very hot and very rainy, these curious phe- 
nomena were frequently seen. Feeling convinced that it must 
exercise a pernicious influence on the health of the horses, we 
took the precaution to have all the windows on that side closed 
every evening, in order thus to exclude as much as possible this 
deleterious gas. 
Towards the end of July, we were informed that several horses 
belonging to one of the Lancer regiments had weak and watery 
eyes. We paid but little attention to this at the time, and merely 
ordered cold water, lotions, and the white regimen. 
In the beginning of August we perceived that the tears corroded 
the cheeks, and were thick with matter — that the conjunctiva was 
red and tumefied, and the eye dull and not very sensitive of the 
light. We bled from the angular vein, and ordered cold watery 
lotions to be continued. 
At first we thought that this ophthalmia was confined to the 
animals that had first been attacked by it ; but before the month 
was out, we saw it developed in at least thirty other horses. In 
most of them the white regimen, scarifications of the conjunctiva, 
bleeding from the angular vein, and lotions with an astringent col- 
lyrium composed of two grains of sulphate of zinc to a drachm of 
distilled water, produced beneficial results ; but in six out of the 
number the disease lasted six weeks. 
The following is an account of its progress : — At first the eyes 
were tearful, the fluid secreted in them destroyed the hair, and 
there was turgescence, redness, and sensibility of the conjunctiva. 
After the lapse of five or six days, the tears became thick and 
purulent ; the eyelids tumefied, and this state continued with unde- 
viating intensity for a fortnight. In the morning the lids could not 
be opened : they were glued together by a thick and plentiful 
discharge. 
On raising them lightly, numerous little ulcerations were ob- 
