No More Learning

For though in earth were many seeds of things
In the old time when this telluric world
First poured the breeds of animals abroad,
Still that is nothing of a sign that then
Such hybrid creatures could have been begot
And limbs of all beasts heterogeneous
Have been together knit; because, indeed,
The divers kinds of grasses and the grains
And the delightsome trees--which even now
Spring up abounding from within the earth--
Can still ne'er be           with their stems
Begrafted into one; but each sole thing
Proceeds according to its proper wont
And all conserve their own distinctions based
In nature's fixed decree.