He ought to make those things which are most inimical, friendly, and excite them to mutual love. But those things are most inimical which are most opposite to each other; cold to heat, bitterness to sweetness, dryness to moisture. Our progenitor, Æsculapius, as the poets inform us, (and indeed I believe them,) through the skill which he possessed to inspire love and concord in these contending principles, established the science of medicine. “The gymnastic arts and agriculture, no less than medicine, are exercised under the dominion of this God. Music, as any one may perceive who yields a very slight attention to the subject, originates from the same source; which Heraclitus probably meant, though he could not express his meaning very clearly in words, when he says, ‘One though apparently differing, yet so agrees with itself, as the harmony of a lyre and a bow.’ It is great absurdity to say that a harmony differs, and can exist between things whilst they are dissimilar; but probably he meant that from sounds which first differed, like the grave and the acute, and which afterwards agreed, harmony was produced according to musical art. For no harmony can arise from the grave and the acute whilst yet they differ. But harmony is symphony: symphony is, as it were, concord. But it is impossible that concord should subsist between things that differ, so long as they differ. Between things which are discordant and dissimilar there is then no harmony. A rhythm is produced from that which is quick, and that which is slow, first being distinguished and opposed to each other, and then made accordant; so does medicine, no less than music, establish a concord between the objects of its art, producing love and agreement between adverse things.