Impromptu

If we may trust the great La Place
The solar system once was gas;
And out of this, together whirled,
Appeared the planets and the world;
Then, through successive waves of change,
Plutonic, chemic, aqueous, strange,
The course of progress slowly ran
Through rocks and protoplasm to man.
(As for the forms, from protoplasm
Through five-toed horses, without chasm,
I need n't say that Huxley has 'em);
And man, as we could tell La Place,
Is chiefly busy making gas!
Thus Nature rounds her wondrous plan,
And ends it just where it began!