Just as agriculture promises nourishment to healthy bodies, so does the Art of Medicine promise health to the sick. Nowhere is this Art wanting, for the most uncivilized nations have had knowledge of herbs, and other things to hand for the aiding of wounds and diseases. This Art, however, has been cultivated among the Greeks much more than in other nations — not, however, even among them from their first beginnings, but only for a few generations before ours. Hence Aesculapius is celebrated as the most ancient authority, and because he cultivated this science, as yet rude and vulgar, with a little more than common refinement, he was numbered among the gods. After him his two sons, Podalirius and Machaon, who followed Agamemnon as leader to the Trojan War, gave no inconsiderable help to their comrades. Homer stated, however, not that they gave any aid in the pestilence or in the various sorts of diseases, but only that they relieved wounds by the knife and by medicaments. Hence it appears that by them those parts only of the Art were attempted, and that they were the oldest.