What are little Boys made of?

I found several Slugs & Snails on the Garden Path today with all the Rain there has been today.

"What are little boys made of?
Slugs and snails, and puppy dogs tails
That's what little boys are made of !"

The origin of the "What are little boys made of" poem can be traced to the early 19th century - the battle of the sexes was raging even then! The words of "What are little boys made of" obviously reflect this, but what is the meaning of 'slugs and snails'? Several interpretations have been suggested but the one with the most credibility is that the original words were in fact 'snips of snails' - the origin of snips meaning 'little bits of'. No redemption there for describing what little boys are made of'!