Doctor Clarke always stopped at his local pub after work for a hazelnut daiquiri  [a special drink the bartender created just for him].

One day, the Dermot, barman ran out of hazelnut flavour so he substituted hickory nuts instead.

Doctor Clarke took one sip of the drink and exclaimed, ‘This isn’t a hazelnut daiquiri. Dermot!’

‘No, I’m sorry’, replied Dermot the barkeeper, ‘it’s a hickory daiquiri, doc.’