Eels live eight years; they are able to survive out of water as much as six days, when a north-east wind blows; but when the south wind prevails, not so many. In winter, they cannot live if they are in very shallow water, or if the water is troubled. They are taken about the rising of the Pleiades when the rivers are turbid. These animals seek their food at night; they are the only fish the bodies of which, when dead, do not float upon the surface. There is a lake called Benacus, in the territory of Verona, in Italy, through which the river Mincius flows. At the part of it whence this river issues, once a year, and mostly in the month of October, the lake is troubled, evidently by the constellations of autumn, and the eels are heaped together by the waves, and rolled on by them in such astonishing multitudes, that single masses of them, containing more than a thousand in number, are often taken in the chambers which are formed in the bed of the river for that purpose. CHAPTER VIII. PECULIAR FISHES. In Northern Gaul the fish called muræna has on the right jaw seven spots, which bear a resemblance to the constellation of the Great Dipper, and are of a gold color, shining as long as the animal is alive, but disappearing as soon as it is dead. Vedius Pollio, a Roman of equestrian rank, and one of the friends of the late Emperor Augustus, found a method of exercising his cruelty by means of this animal, for he caused such slaves as had been condemned by him, to be thrown into preserves filled with murænæ; not that the land animals would not have fully sufficed for this purpose, but because he could not see a man so aptly torn to pieces all at once by any other kind of animal. It is said that these fish are driven to madness by the taste of vinegar. Their skin is exceedingly thin; while that of the eel, on the other hand, is much thicker. Verrius informs us that formerly the children of the Roman citizens, while wearing the prætexta, were flogged with eel-skins. There is a very small fish that is in the habit of living among the rocks, and is known as the echeneis.[138] It is believed that when this has attached itself to the keel of a ship its progress is impeded, and from this circumstance it takes its name. Mucianus speaks of a murex of larger size than the purple murex with a head that is neither rough nor round; and the shell of which is single, and falls in folds on either side. He tells us, also, that some of these creatures once attached themselves to a ship freighted with children of noble birth, and that they stopped its course in full sail. Trebius Niger says that this fish is a foot in length, and that it can retard the course of vessels, five fingers in thickness; besides which, it has another peculiar property—when preserved in salt, and applied, it is able to draw up gold which has fallen into a well, however deep it may happen to be.