The worship of subterranean deities, representing the hidden forces of nature, is said to have been a chief feature of the religion of the prehistoric Pelasgians inhabiting Greece; and it was believed that if once the particular formula or spell, wherein lay the secret of their power, could be discovered, these deities might be rendered subservient to the will of man.[120:2] Similarly, in many religions of antiquity, the names of deities were invested with great power, and whoever uttered them was "master of the god."[120:3] Cato the Censor (B. C. 234-149), in his treatise "De Re Rustica," chapter 157, recommended a written charm for the cure of fractures; and Ovid (B. C. 43-A. D. 18), in his "Metamorphoses," wrote these lines: "By means of incantations I break in twain the viper's jaws." In very early times physicians were regarded as under the protection of the gods, and the magical charms employed by them were therefore naturally invested with supernatural curative power. Melampus, a noted mythical leech of Argos, before the Trojan War, was said to have made use of healing-spells in his practice. Professor H. Blümner, in "The Home Life of the Ancient Greeks," chapter 7, remarks that, in the early historic era, medicine developed especially in two directions in Greece: namely, as practised by a regular medical fraternity; and secondly, "as a kind of religious mystery in the hands of the priests." The latter system was doubtless connected with the worship of Esculapius. But quacks and charlatans were much in evidence, even in that remote epoch. Francis Bacon, in his "Advancement of Learning," chapter 2, says that "the poets were clear-sighted in discerning the credulity of men in often preferring a mountebank, or a cunning woman to a learned physician. Hence they made Esculapius and Circe brother and sister, and both children of Apollo." The Grecians believed that petitions offered in a foreign tongue were more favorably received than those in the vernacular; and as a reason for this belief it was alleged that the earliest languages, however barbarous and strange to classic ears, contained words and names which were somehow more consonant to nature and hence more pleasing to their deities.[121:1] Especial magical efficacy has always been ascribed to certain Hebrew, Arabian, and Indian words.[121:2] Aëtius, who lived at Amida in Mesopotamia in the fifth century, the first Christian physician whose medical writings are extant, repeated biblical verses during the preparation of his medicines, in order to increase their efficacy.[122:1] And until comparatively modern times, the employment of verbal charms, curative spells, and formulas, was believed to enhance the therapeutic virtues of medicines. No remedy, we are told, was administered without mysterious ceremony and incantation.