I've read that hidden in 'An Enigma' by Edgar Allan Poe is the name of the woman to whom the poem is addressed... and that a simple key unlocks the secret... but I've tried in vain to find figure it out! Can someone help me out please? Thanks!

[The hidden name in this poem is that of Sarah Anna Lewis. It is spelled with one letter on each line, the first letter of the first line "S", the second letter of the second line "a", the third letter of the third line "r", etc.]