Humpty Dumpty

Where does it say that Humpty Dumpty was an egg?  Huh?  Where?

Humpty Dumpty sat on a wall,

Humpty Dumpty had a great fall,

And all the king’s horses and all the king’s men,

Couldn’t put Humpty together again…

I mean I’m not too surprised that the horses didn’t have much success fixing it, whatever it was… but nowhere does it say ‘egg’.  Nowhere.

It’s driving me insane.