Advice To Sonnet Writers 3: A Critic of Poetry

I heard a critic in a certain town
Lecture on Poetry. As butterflies,
Like sapphire spangles fallen from splendid skies,
On a stiff piece of cardboard are pinn'd down,
So dealt he with great verses, of renown
Them disenchanting, and their rich surprise.
He told the poets off by families,
Scarce one with beauty of his very own.
‘I hold song separate from the man himself;
I hold it for a delicate verbal trick.
Dainty work here!—this is the way he does it:
He puts me up a private colour-shelf;
Drawing a flower, he steals red tints to rose it.
Poetry's a pretty branch of rhetoric!’