Of substance I've thought, and the varied disputes...

Of substance I've thought, and the varied disputes On the nature of man and the notions of brutes; Of systems confuted, and systems explain'd; Of science disputed, and tenets maintain'd. These, and such speculations on these kind of things, Have robb'd my poor Muse of her plume and her wings; Consumed the phlogiston you used to admire, The spirit extracted, extinguish'd the fire; Let out all the ether, so pure and refined, And left but a mere caput mortuum behind.