10. The greatest number of fish are taken before sunrise and after sunset, or just about sunrise and sunset, for the casts made at this period are called seasonable. For this reason the fishermen take up their nets at this time, for the sight of the fish is then most readily deceived. During the night they remain quiet, and at mid-day, when the light is strong, they see very well. 11. Fish do not appear to be subject to any of those pestilential diseases which so often occur among men and quadrupeds, as the horse and ox, and other animals, both domestic and wild. They appear, however, to suffer from ill health, and the fishermen consider that this is proved by the capture of some lean, and apparently weak individuals, and others that have lost their colour, among a number of fat ones of the same kind. This is the nature of sea-fish. 12. No pestilential disease attacks river and pond fish, though some of them are subject to peculiar diseases, as the glanis, from its swimming near the surface, appears to be star-struck by the dog-star, and it is stupefied by loud thunder. The carp suffers in the same way, but not so severely. The glanis, in shallow water, is often destroyed by the dragon-serpent. In the ballerus and tilon a worm is produced, under the influence of the dog-star, which makes them rise to the surface and become weak, and when they come to the surface they are killed by the heat; a violent disease attacks the chalcis, which is destroyed by a number of lice, which are produced under its gills; no other fish appear to be subject to such a disease. 13. Fishes are poisoned with the plant called mullein, for which reason some persons capture them by poisoning the waters of rivers and ponds; and the Phœnicians poison the sea in the same way. There are two other plans which are adopted for the capture of fish; for since fish avoid the deep parts of rivers in cold weather (for even otherwise the river water is cold), they dig a ditch through the land to the river, which they cover over with grass and stones so as to resemble a cave, with one opening from the river, and when the frost comes on they capture the fish with a basket. The other mode of fishing is practised both in summer and winter. In the middle of the stream they raise a structure with faggots and stones, leaving one part open for a mouth; in this a basket is placed, with which they catch the fish, as they take away the stones. 14. Rainy years agree with all the testacea except the purpura; this is a proof of it, if placed near the mouth of a river, they take the fresh water, and die the same day. The purpura will live about fifty days after it has been taken. They are nourished by each other, for a plant like a fucus or moss grows upon their shells. They say that whatever is cast to them for food is done for the sake of weight, that they may weigh the more.