Heedless they comply, 450 Till the whole soul from that mysterious draught Is tinged, and every transient thought imbibes Of gladness or disgust, desire or fear, One homebred colour, which not all the lights Of Science e'er shall change; not all the storms Of adverse Fortune wash away, nor yet The robe of purest Virtue quite conceal. Thence on they pass, where, meeting frequent shapes Of good and evil, cunning phantoms apt To fire or freeze the breast, with them they join 460 In dangerous parley; listening oft, and oft Gazing with reckless passion, while its garb The spectre heightens, and its pompous tale Repeats, with some new circumstance to suit That early tincture of the hearer's soul. And should the guardian, Reason, but for one Short moment yield to this illusive scene His ear and eye, the intoxicating charm Involves him, till no longer he discerns, Or only guides to err. Then revel forth 470 A furious band that spurn him from the throne, And all is uproar. Hence Ambition climbs With sliding feet and hands impure, to grasp Those solemn toys which glitter in his view On Fortune's rugged steep; hence pale Revenge Unsheaths her murderous dagger; Rapine hence And envious Lust, by venal fraud upborne, Surmount the reverend barrier of the laws Which kept them from their prey; hence all the crimes That e'er defiled the earth, and all the plagues 480 That follow them for vengeance, in the guise Of Honour, Safety, Pleasure, Ease, or Pomp, Stole first into the fond believing mind.