See subject query.
Maybe I knew once when I learned it.
Thnx.
Three minutes…
The article mentioned, but only in passing, the possibility that it was originally “snips OF snails.” I think this is by far the most likely answer. It maintains the parallelism: boys are made of 1. snips of snails (amputated animal body part) and 2. puppy dog tails (amputated animal body part) while girls are made of 1. sugar (tasty food) and 2. spice (also tasty food) and, by the way, 3. everything nice (vague filler phrase that rhymes, maintains meter, and makes up for the unfortunate fact that sugar and spice are only one syllable.)
The composer probably first thought: what’s the grossest thing? Answer: in a combination of violence and scatology, a mutilated bit of a dog, which aren’t considered clean animals, and in fact the bit which spends all its time right next to a butthole. Then they thought: how can I fill out this line? And ‘snips and snails’ kind of fit. But ‘snips and snails’ was not an otherwise familiar phrase, so in the transmission, people naturally assumed that a ‘snip’ was a noun. Hence the change.
I think it’s also possible that a similar-sounding vernacular/foreign word was made into ‘snips’ by the telephone game of children. Plus, it’s possible that it was bowdlerized. Perhaps it was ‘shits and snails,’ who knows. (Shits and snails are fine go-tos as candidates for the the opposite of tasty food among the nonfrench, which would again maintain the parallelism.)
It was always ‘slugs and snails’ when I was a boy.
Of course, it was common back in the day, for puppies tails to be cut off for various reasons.
Apparently Southey wrote two other forgotten verses:
*What are young men made of?
Sighs and Leers
And crocodile tears
That’s what young men are made of.
What are young women made of?
Ribbons and Laces
And sweet pretty faces
That’s what young women are made of.*
Enough to make any modern egalitarian cringe.
There is also a version with “frogs and snails.” I seem to recall one of my first threads here on the Dope almost twenty years ago (wow) dogging up all the variations.
Heh, rereading that thread, I’m amused by the references to alltheweb.com. Totally forgot about that search engine, but it was one where you can do a true exact match string search. Looks like there are a lot of variations on that first word.
Where did you live when you were a boy?
I lived in Upstate New York and I’ve never encountered slugs and snails before this.
In the thread I linked to, it seems most of the respondents for “slugs and snails” are from the UK or Ireland (looks like it’s by far the dominant version there.) We uncovered the following versions, in order of popularity according to the alltheweb and altavista search engines at the time: “snips, snakes, frogs, slugs, rats, sticks, snaps, ships, nails, snits, worms, snipes.” The earliest recorded one seems to be “frogs and snails,” as samclem and a Ph.D. in Childrens Lit I emailed posit. Surprisingly, the next verifiable printed version seems to be “snaps and snails,” and then “snips and snails.” But this was in 2001; who knows what academic research on this important topic has uncovered since then. 
Ah, bob++'s profile says Worcestershire, UK, so that checks out with why “slugs and snails” would have been the version he’s familiar with.
I think the wide variation of, uh, variations which aren’t phonetically similar would point the needle a little further toward it being a bowdlerization.
Apparently Americans do alter the rhyme at times, because someone online dug this up.
Piggins? WTF?
Wiktionary defines a piggin as
Forget snips. I want to know where piggins came from.
Not in Utica, no. It’s more of an Albany expression.
I recall reading (don’t recall where) that “snips” meant the odds and ends a little boy was apt to carry in his pockets… a bit of kite string, perhaps, a cracked marble, a found (“lucky”) penny, an interesting pebble, a broken whistle…all the stereotypical jetsam of a boy’s life.
It’s always seemed to me that “puppy dogs tails” refers to a boy’s penis. I may be wrong, but it makes sense.
For a rhyme that was probably coined in an era when small children frequently ran around naked, it would make sense to me too.
I must say you steam a good snail.