This is called "When You Walk Over the Earth."
And I don't think you need to know anything.
"When you walk over
The earth, it asserts itself.
It says to your
Feet, here, here, here.
You must reckon
With the Earth, though it enters
You less unless the sky always
Has its hand in you,
As if you were a puppet,
Through your ears, down
Your throat, into your
Lungs-- and with the tips
Of its fingers there, it caresses
Every capillary, each blood cell,
Until they blush."