I had to Google "purrel -purell" to track that down, and even then it wasn't an immediate hit.

According to WordNik.com, which cites the "Century Dictionary", a purrel is "A list ordained to be at the end of kersies to prevent deceit in diminishing their length."

Wasn't that helpful?! According to Wiktionary, a kersie is Afrikaans for cherry.

Ergo a purrel is a list at the end of cherries to prevent lies about their length. Clear as mud, eh?

(Yes, none of this is helpful at all, but I'm cracking up)

http://www.wordnik.com/words/purrel http://en.wiktionary.org/wiki/kersie