Literary reference puzzle

[Golem]

A line in a book, "Then and now we age with the grace (in Cummings's careful metaphor) of polar bears on rollerskates."

Am I correct in thinkng this is a reference to ee cummings, and if so, what is the 'careful metaphor'?

Thanks

[Clanad]

Possibly cummings, although I can find no citation. The reference to 'careful metaphor' probably relates to the only slight differences between a metaphor and simile... the two being so closely related that if one's intention is to construct and use a metaphor one must be certain it doesn't slip on a banana peel like a red nosed clown and become a simile. e.e. cummings poetry is really all about structure... somewhat similar, in my opinion, to haiku. However Cummings was equally comfortable with a metaphor as he was with a simile... (Nice to see you again Golem)