Herodotus says: “The means devised by the Egyptians to avoid the Gnats, which swarm in prodigious numbers, are these: Those who reside at some elevation above the marshes, avail themselves of towers which they ascend to sleep; for the Gnats, to avoid the winds, do not fly high. While those who dwell on the very margins of the marshes, instead of towers, practise another contrivance. Every man possesses a net, which, during the day, he employs in catching fish, and which at night he uses as his bed-chamber, where he places it over his couch, and so sleeps within it. For if any one,” he concludes, “sleeps wrapped in a cloak or cloth, the Gnats will bite him through it; but they never attempt to penetrate the net.”[945] With regard to the conclusion of Herodotus, that nets with meshes will effectually exclude Gnats, Tennent says he has “been satisfied by painful experience that (if the theory be not altogether fallacious) at least the modern mosquitoes of Ceylon are uninfluenced by the same considerations which restrained those of the Nile under the successors of Cambyses.”[946] Jackson complains that after a fifty-miles journey in Africa, the Gnats would not suffer him to rest, and that his hands and face appeared, from their bites, as if he was infected with the small-pox in its worst stage.[947] Dr. Clarke relates that in the neighborhood of the Crimea, the Russian soldiers are obliged to sleep in sacks to defend themselves from the mosquitoes; and even this, he adds, is not a sufficient security, for several of them die in consequence of mortification produced by these furious blood-suckers.[948] When we consider these circumstances, it is not incredible that the army of Julian the Apostate should be so fiercely attacked by these insects as to be driven back; or that the inhabitants of various cities, as Mouffet has collected from different authors,[949] should, by an extraordinary multiplication of this plague, have been compelled to desert them. Also the latter part of the following story, related by Theodoret, seems entitled to belief: When Sapor, King of Persia, says this historian, was besieging the Roman City of Nisibis in the year 360, James, Bishop of that city, ascended one of the towers, and “prayed that Flies and Gnats might be sent against the Persian hosts, that so they might learn from these small insects the great power of Him who protected the Romans.” Scarcely had the Bishop concluded his prayer, continues Theodoret, when swarms of Flies and Gnats appeared like clouds, so that the trunks of the elephants were filled with them, as also were the ears and nostrils of the horses and of the other beasts of burden; and that, not being able to get rid of these insects, the elephants and horses threw their riders, broke the ranks, left the army, and fled away with the utmost speed; and this, he concludes, compelled the Persians to raise the siege.[950]