How does C. S. Lewis use imagery in Perelandra?

Imagery:

"The smells in the forest were beyond all that he had ever conceived. To say that they made him feel hungry and thirsty would be misleading; almost, they created a new kind of hunger and thirst, a longing that seemed to flow over from the body into the soul and which was a heaven to feel."

"This itch to have things over again, as if life were a film that could be unrolled twice or even made to work backwards...was it possibly the root of all evil?"