A Grain of Salt

I’m back to inviting readers to submit quotations whose origins they want me to try to trace, using my book, The Yale Book of Quotations, and my more recent researches.
Jamie asked:

‘Take it with a grain of salt’ is one I always have trouble with – do you know the origin?

(iStockphoto)

The Yale Book of Quotations has the following entry:

“Addito salis grano
With the addition of a grain of salt.
Pliny the Elder, Historia Naturalis bk. 23, sec. 149.  Usually quoted as ‘Cum grano salis’ (with a grain of salt).  The reference is to salt being added to Pompey’s antidote to poison.”
 

Jim asked:

How about ‘If you love somebody set them free. If they come back to you…’  My quick web search didn’t yield anything definitive.

The YBQ is all over this one, with the following entry:

If you want something very, very badly, let it go free. If it comes back to you, it’s yours forever. If it doesn’t, it was never yours to begin with.
Jess Lair, I Ain’t Much, Baby — But I’m All I Got (1974).  Lair had his students at Montana State University write comments, questions, or feelings on index cards.  This passage appeared on one of the students’ cards, although it might have been copied by the student from another source.  When these words became famous, a harsh parody arose:  ‘If you want something very very badly, let it go free.  If it doesn’t come back to you, hunt it down and kill it.'”

Do any readers have any other quotations whose origins they would like me to attempt to trace?