The environing snows of Greenland could not cloak

Its little foxes with their whiter fur.

Nor could the wing-shut butterfly’s inner will

Mimic the shrivelled leaf on the withered bough

So cunningly that the bird might perch beside it

And never see its prey.

Was it blind chance

That flashed his own great fragment of the truth

Into his mind? What vera causa, then,

What leap of Nature brought that truth to birth,