Travels in Africa, Egypt, and Syria, from the year 1792 to 1798

by William George Browne

The Nile water, it may be supposed, when taken into the stomach, can have no effect on the eyes, but by first altering the state of the fluids, into which it, as well as other aliments, is gradually converted. Whether from mineral or vegetable impregnations, it could never operate solely on the eyes, without affecting any other part of the animal economy. The effect of opium is seen on the blood and muscular fibres; of mercury on the glands and lymphatics; of cantharides on the nerves: and too great a portion of these, taken into the body, may have a pernicious effect on the eyes, but always through the medium of other parts. The whole materia medica, perhaps, furnishes no drug or mineral that is known, when taken into the stomach, to have a local and partial effect on the eyes. Such an effect is even irreconcileable with the general and constantly observed operation of all remedies applied to the human body.

Besides, if the injury were solely or even in part to arise from the use of the Nile water, all those who drink it must be equally affected, allowing for the different degree of firmness in the stamina of each. But certain orders of men are rarely attacked by this disease, and they too who are continually using the river water both internally and externally.

Rice is one of the most nutritive and salubrious of the farinaceous aliments, and certainly does not operate to render the humours acrid, and thereby to inflame the eyes. It is used as a main article of food by the natives of a large portion of Asia, and forms no inconsiderable part of the consumption in other countries, without being observed to produce any such effect as is here attributed to it; and may therefore fairly be denied to have any such power.

Something more plausible indeed offers itself as to the injurious operation of an external cause. Nothing can be more subtle than the dust into which the vegetable soil of Egypt resolves itself when it becomes dry. This, during a certain portion of the year, is in a manner suspended in the air, from a cause which exists in few other countries, I mean the want of rain. It also contains a large portion of nitre, which is copiously produced in Egypt. This circumstance, however, is common to many other places. This light dust, doubtless of a very irritating quality, not only floats in the streets, but pervades the apartments of every dwelling, insinuating itself into the most artfully constructed inclosures: by it therefore the eyes may and must be in some degree affected. But Nature has not ordained that a part so much exposed should be destitute of its appropriate protection. The secretions of the lachrymal glands are, in general, abundantly sufficient to counteract the injury sustained by the action of corrosive or irritating substances on the external fabric of the eye, being always produced exactly in proportion to the circumstances that demand them, as daily experience confirms: yet it cannot be denied, that the continually repeated operation of an offending cause, when no remedy is applied, may be more than commensurate with the efforts of Nature to restore herself.

Such is precisely the condition of the Kahirines. The accommodating the quality of diet to the symptoms of derangement in the economy is a precaution unknown to them: and of their remedies, many are so prepared, or so administered, as to augment rather than to annihilate disease. No idea offers itself to them, but of topical applications to remove a local complaint. If any thing be applied in these flussioni (dysophthalmia) it is generally kôhhel (calx of tin mixed with sheep’s fat) or tûtti, a still more powerful astringent, applied in coarse powder, and naturally tending to increase rather than to allay the irritation.

When thus incommoded, the Egyptians of the lower class esteem water pernicious, and therefore rarely wash their eyes; but as the collected dust begins to cause an uneasy sensation, apply their fingers or a coarse cotton cloth to remove it. The higher orders, who are neat in their persons, and regular in their ablutions, are rarely observed to be greatly harassed by this complaint. And the progress of the disorder, when in its nascent state, has several times been stopped, under my observation, by the use of rose-water, solution of sacchar. saturn. &c. as in other places.

But as no single one of these causes, nor even all of them together, appear sufficient to account for all the phenomena, another, more powerful, is to be sought; and none suggests itself more opportunely than that alleged by Savary, who imagines that the defect of vision is principally brought about by the habit of being exposed to the nocturnal air during the summer, at which season a heavy dew falls, and a great transition happens from the heats of the day. In fact, if the face of those who sleep exposed be not completely covered, an itching and unpleasant sensation is always felt in the eyes at rising.

It is ordinarily experienced in the city, where, from being confined in the day, people feel most disposed to seek for coolness and refreshment on their terraces at night.

The Mamlûks, and higher order of Arabs, that is, Mohammedan merchants, and the superior rank of Copts and Franks, are least affected, as being cleanly, not exposing themselves to the night air without necessity, and being well covered. The Arabs of the desert are as free from blindness as any people. They never sleep with the face exposed, and have moreover the advantage of being devoid of the dust and other supposed causes of psorophthalmia in the city. The disorder appears no where so much as in Kahira, because no where are all the causes so much combined: yet it is seen in Alexandria, Damiatt, and in Upper Egypt, which shews that the cause is not confined to Kahira. Among the poorer class of all countries prevails a kind of insouciance. That of Kahira is particularly exposed to the changes of temperature and the nocturnal dew, and is ill clothed. Hence the disorder is mostly found among the populace. A disposition to inflammation often appears in the eyes of children, but yields to proper remedies. Hence it may be imagined, that with attention the Egyptians would not suffer more than other nations.

Some travellers have thought that the ophthalmic disease in Kahira was occasioned by the fetid exhalations of the Chalige, and the drains; and have even observed, that those who are most severely affected in winter, recover as soon as the water has filled the Chalige and the pools. This is also a common idea with the natives. “The stink blinds me,” is a frequent expression on coming into a place of fetid odour; and it may be remarked, that the ordinary maxims of indigenæ are rarely to be entirely disregarded. Whatever miasms however may issue from the canal, they cannot be equally dispersed over the city, as blindness is; and the Franks, Greeks, and other strangers who reside nearest this depôt of impurity, would be most affected if that were the cause. It may yet be one cause. Another I take to be the subtile dust above mentioned; but the most powerful, indiscreet exposure to the nocturnal air and dews. The collective influence of these is strengthened by the cloudless splendour of a vertical sun, reflected from the sterile expanse of sand, which offers no sombrous object on which the eye may repose itself.