Strickland Gillilan's poem was composed in the early 1900s, and is also known by the alternative title Fleas.
I might as well quote it in full:
It's compact, it scans, it rhymes, it's funny, and it provides much matter for reflection.
Word To Use Today: flea. The Old English form of this word was flēah: so presumably Edward the Confessor had them, too.