E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
A security for money. John de Castro of Portugal, having captured the castle of Diu, in India, borrowed of the inhabitants of Goa 1,000 pistoles for the maintenance of his fleet, and gave one of his whiskers as security of payment, saying, All the gold in the world cannot equal the value of this natural ornament, which I deposit in your hands.