The solemn death-rites of the Egyptians were practised by priests and physicians, aided by professional embalmers; and their daily practice must have led to a knowledge of many physiological facts advantageous to the science of medicine. The search after substances calculated to preserve the body could not fail to lead to chemical discoveries of equal value to the arts. The country itself furnished some of these substances, but Arabia and the neighbouring nations still more. Among these, the asphaltum, pissasphaltum, and petroleum, brought from the Dead Sea, from Babylon, and from the province of Mazenderan, appear to have been most generally used; and it is a curious fact, that a substance arising from the partial decomposition of the bodies, mixed with these mineral substances, should, very early under the name of mummy, have been employed by Arabian and Jewish physicians in medicine. It is still stranger that it should have kept its place in the materia medica of most nations till very lately, and I question whether it be yet entirely expunged from them. As a colouring matter, the same mummy was highly esteemed, and is still often used. But it is giving way to other preparations of asphaltum with wax, oil, or some equivalent substance. The prejudice which led to the seeking among the costly embalmed bodies of Egypt a remedy for disease, is akin to that which is not yet quite exploded even in England, and which leads the vulgar to pass the hand of a hanged man over scrophulous swellings as a certain cure. From this strange superstition even Boyle was not so free, but that, in giving a recipe for some preparation, he mentions the calcined arm bone of a _hanged_ man reduced to powder as an ingredient! This same prejudice, or something like it, led the painters of antiquity to rake, as Pliny says, among the ashes of a funeral pile for a superior black pigment, and induced more modern artists to use mummy brown. The common bitumen or asphaltum, was known by the early physicians to mix readily with oil, and was much used as an external application; very ancient artists also varnished their statues of wood or metal with that mixture, to preserve them from the action of the air[265]. But there was a finer substance, called by Pliny an earth, ampelitis, which being softened in oil worked like wax. Besides the use of the ampelitis for plasters, the antique men of the world used it to blacken their eyebrows and colour their hair[266]. With these uses of asphaltum and ampelitis, softened or dissolved in oil, the antique painters must have been familiar, and it is difficult to imagine that they did not avail themselves of so agreeable a colour and varnish. It answers, in a great degree, to the account given of the dark fluid with which Apelles varnished his pictures. It would certainly preserve them from the effects of dust and wet; it would make the colours richer, and, at the same time, soften the harshness of the more glaring ones.