Th' Eternal Art, educing good from ill,[1203] 175 Grafts on this passion our best principle: 'Tis thus the mercury of man is fixed,[1204] Strong grows the virtue with his nature mixed; The dross cements what else were too refined, And in one int'rest body acts with mind. 180 As fruits, ungrateful to the planter's care, On savage stocks inserted learn to bear,[1205] The surest virtues thus from passions shoot,[1206] Wild nature's vigour working at the root.[1207] What crops of wit and honesty appear 185 From spleen, from obstinacy, hate or fear![1208] See anger, zeal and fortitude supply;[1209] Ev'n av'rice, prudence; sloth, philosophy; Lust, through some certain strainers well refined, Is gentle love, and charms all womankind; 190 Envy, to which th' ignoble mind's a slave, Is emulation in the learn'd or brave;[1210] Nor virtue, male or female, can we name, But what will grow on pride,[1211] or grow on shame.[1212] [Sidenote: Virtue and vice joined in our mixed nature; the limits near, yet the things separate and evident. The office of reason.] [1213]Thus nature gives us (let it check our pride)[1214] 195 The virtue nearest to our vice allied;[1215] Reason the bias turns to good from ill,[1216] And Nero reigns a Titus if he will.[1217] The fiery soul abhorred in Catiline, In Decius charms, in Curtius is divine:[1218] 200 The same ambition can destroy or save, And makes a patriot as it makes a knave.[1219] This light and darkness in our chaos joined, What shall divide? The god within the mind.[1220] Extremes in nature equal ends produce, 205 In man they join to some mysterious use;[1221] Though each by turns the other's bound invade, As, in some well-wrought picture, light and shade,[1222] And oft so mix, the diff'rence is too nice[1223] Where ends the virtue, or begins the vice. 210 Fools! who from hence into the notion fall, That vice or virtue there is none at all. If white and black blend, soften, and unite A thousand ways, is there no black or white?[1224] Ask your own heart, and nothing is so plain; 215 'Tis to mistake them costs the time and pain.[1225] [Sidenote: Vice odious in itself and how we deceive ourselves into it.]