Ophthalmia prevailed most in the 61st regiment; after them, in the 86th regiment: while the 8th dragoons, the artillery, and the 80th regiment, had very little of the disease. It was remarked, at all times, that the disease was seen much less frequently, and with less violence, in the native Indian, than in the European, corps. Of the former, the 1st Bombay regiment had much more ophthalmia than any other corps of natives. It was said, that, in the English army, the disease prevailed most in the dragoon-regiments. The 26th dragoons was mentioned as a particular instance of this: that corps alone, I heard, sent home about 40 invalids from ophthalmia. Several gentlemen thought that this disease, in Egypt, was contagious.[6] So singular an opinion I would hesitate to offer on slender grounds. However, the remarkable prevalence of the disease in particular regiments, and even in particular companies of regiments, while the same general causes prevailed every where, will not be easily accounted for, without admitting something of the kind. In some corps of the army from England, as well as that from India, this was observed. In the 54th regiment, my friend, Mr Ross, then the surgeon of it, informed me that the disease was for some time not only confined to particular companies, but to particular tents. It deserves mention, too, that, till the arrival of the Indian army at Ghiza, ophthalmia did not appear in the army. We found at Ghiza the 89th regiment and an ophthalmia-hospital of the English army. I believe that several diseases are contagious, which are not suspected to arise from such a cause: the theory of contagion is but very imperfectly understood. It was said, that the sailors, on-board the fleet at Aboukir-bay, had the disease at the same time that it prevailed in the army on-shore. Several cases appeared among the troops after we sailed from Suez. Ophthalmia prevailed most from May to December. At Kossier the disease was hardly seen, nor at Ghenné. It was not till the army was encamped at Rhoda, in August, that cases crowded in on us. In that, and the two following months, most of the cases made their appearance. It will be seen, in part the first of these sketches, that, in the months of January, February, March, and April, very few cases appear in the reports. About the middle of May the disease began to appear in Alexandria.