Dragon fables have this undertone to their brave strain. In the Rig Veda (v. 32) it is said that when Indra slew Ahi, 'another more powerful was generated.' Isaiah (xiv. 29) cries, 'Rejoice not thou, whole Palestina, because the rod of him that smote thee is broken: for out of the serpent's root shall come forth a cockatrice, and his fruit shall be a fiery flying serpent.' Herakles struggles with the giant robber, Antæus, only to find the demon's strength restored by contact with the earth. He kills one head of the Hydra only to see two grow in its place; and even when he has managed to burn away these, the central head is found to be immortal, and he can only hide it under a rock. That one is the self-multiplying principle of evil. The vast brood of Echidna in mythology expresses the brood of evil in nature. Echidna, daughter of Ge and Tartarus, Earth and Hell--phonetic reappearance of Ahi--is half-serpent, half-woman, with black eyes, fearful and bloodthirsty. She becomes the mother of fire-breathing Typhon, buried beneath the earth by Jove's lightning when he aspired to scale Olympus; of the Dragon that guarded the Hesperian garden; of the Sphinx which puzzled and devoured; of three-headed Cerberus; of the eagle that preyed on rock-bound Prometheus; of the Nemæan lion which Herakles slew; of Chimæra; and of Scylla the monster whom Homer describes sitting between two large rocks waylaying mariners on the way from Italy to Sicily,--possessing twelve feet, six long necks and mouths, each with three rows of rushing teeth. The Dragon that Cadmus slew also had terrible teeth; and it will be remembered that when these teeth were sown they sprang up as armed men. Like them, the ancient Dragon-myths were also sown, broadcast, in the mental and moral fields, cleared and ploughed by a new theology, and they sprang up as dogmas more hard and cruel than the ferocious forces of nature which gave birth to their ancestral monsters. What the superstitious method of interpreting nature, forced as it is to personify its painful as well as its pleasant phenomena, inevitably results in, finds illustration in the two great lines of tradition--the Aryan and the Semitic--which have converged to form the christian mythology.