Their differing physiologies.
Firmness of apple, fluted shape
Of celery, or tight-skinned grape
I grind and mangle when I eat,
Then in dark, salt, internal heat,
Annihilate their natures by
The very act that makes them I.
But when the soul partakes of good
Or truth, which are her savoury food,
By some far subtler chemistry
It is not they that change, but she,
Who feels them enter with the state
Of conquerors her opened gate,
Or, mirror-like, digests their ray
By turning luminous as they. —C.S. Lewis