Ver. 88. _Those rules of old, &c._] Having thus, in his first precept, to follow nature, settled criticism on its true foundation; he proceeds to show, what assistance may be had from art. But lest this should be thought to draw the critic from the ground where our poet had before fixed him, he previously observes, from ver. 87 to 92, that these rules of art, which he is now about to recommend to the critic's observance, were not invented by abstract speculation; but discovered in the book of nature; and that therefore, though they may seem to restrain nature by laws, yet as they are laws of her own making, the critic is still properly in the very liberty of nature. These rules the ancient critics borrowed from the poets, who received them immediately from nature. Just precepts thus from great examples giv'n, These drew from them what they derived from heav'n, so that both are to be well studied. Ver. 92. _Hear how learn'd Greece, &c._] He speaks of the ancient critics first, and with great judgment, as the previous knowledge of them is necessary for reading the poets, with that fruit which the end here proposed requires. But having, in the foregoing observation, sufficiently explained the nature of ancient criticism, he enters on the subject treated of from ver. 91 to 118, with a sublime description of its end; which was to illustrate the beauties of the best writers, in order to excite others to an emulation of their excellence. From the raptures which these ideas inspire, the poet is brought back, by the follies of modern criticism, now before his eyes, to reflect on its base degeneracy. And as the restoring the art to its original purity and splendour is the great purpose of this poem, he first takes notice of those, who seem not to understand that nature is exhaustless; that new models of good writing may be produced in every age; and consequently, that new rules may be formed from these models, in the same manner as the old critics formed theirs, which was, from the writings of the ancient poets: but men wanting art and ability to form these new rules, were content to receive and file up for use, the old ones of Aristotle, Quintilian, Longinus, Horace, &c. with the same vanity and boldness that apothecaries practise, with their doctors' bills: and then rashly applying them to new originals (cases which they did not hit) it was no more in their power, than in their inclination, to imitate the candid practice of the ancients when The gen'rous critic fanned the poet's fire, And taught the world with reason to admire.