The myax[258] is of a purgative nature, a shell-fish of which we shall take this opportunity of giving the natural history at length. These fish collect together in masses, like the murex,[259] and are found in spots covered with sea-weed. They are the finest eating in autumn, and are found in the greatest perfection in places where fresh-water streams discharge themselves into the sea; for which reason it is that those of Egypt are held in such high esteem. As the winter advances, they contract a bitter flavour, and assume a reddish hue. The liquor of these fish, it is said, acts as a purgative upon the bowels and bladder, has a detergent effect upon the intestines, acts aperiently upon all the passages, purges the kidneys, and diminishes the blood and adipose secretions. Hence it is that these shell-fish are found of the greatest use for the treatment of dropsy, for the regulation of the catamenia, and for the removal of jaundice, all diseases of the joints, and flatulency. They are very good, also, for the reduction of obesity, for diseases of the bile and of the pituitous secretions, for affections of the lungs, liver, and spleen, and for rheumatic defluxions. The only inconvenience resulting from them is, that they irritate the throat and impede the articulation. They have, also, a healing effect upon ulcers of a serpiginous nature, or which stand in need of detergents, as also upon carcinomatous sores. Calcined, the same way as the murex, and employed with honey, they are curative of bites inflicted either by dogs or human beings, and of leprous spots or freckles. The ashes of them, rinsed, are good for the removal of films upon the eyes, granulations of those organs and indurations of the membrane, as also for diseases of the gums and teeth, and for pituitous eruptions. They serve, also, as an antidote to dorycnium[260] and to opocarpathon.[261] There are two species of this shell-fish, of a degenerate kind: the mitulus,[262] which has a strong flavour, and a saltish taste; and the myisca,[263] which differs from the former in the roundness of its shell, is somewhat smaller, and is covered with filaments, the shell being thinner, and the meat of a sweeter flavour. The ashes, also, of the mitulus, like those of the murex, are possessed of certain caustic properties, and are very useful for the removal of leprous spots, freckles, and blemishes of the skin. They are rinsed, too, in the same manner as lead,[264] for the removal of swellings of the eyelids, of indurations of the membranes, and of films upon the eyes, as also of sordid ulcers upon other parts of the body, and of pustules upon the head. The meat of them, also, is employed as an application for bites inflicted by dogs.