When one takes shoes to a shop to be mended, one is given a ticket with a number on it. Then, when one's shoes are ready, one goes back to the shop, gives the ticket to the shoemaker, gets one's shoes and pays for them.
One day Mrs Smith gave her husband a pair of her shoes which needed mending and asked him to take them to the shop. Mr Smith did so, and put the ticket for them in his pocket.
He went back four days later to get the shoes, but when he went into the shop, he was not able to find his ticket again, and the shoemaker did not want to give him the shoes until he got the ticket.
'How do I know that the shoes are yours unless you give me the ticket?' he said, 'If I give them to you now, somebody else may come into my shop with the ticket tomorrow, and then I shall not be able to give him the shoes.'
Mrs. Smith needed the shoes urgently, so her husband thought for a moment and then went out to his taxi, which was at the side of the road outside the shop. He opened the door, and whistled to his wife's small dog, which was sitting on the back seat. Then he went back into the shop with it and said to it, 'Get the shoe!' The dog began to smell around the shop, and soon it recognized Mrs Smith's shoes and brought them to Mr Smith one after the other.
'That should prove that they are my wife's,' suggested Mr Smith.
The shoemaker laughed, 'It certainly does! That is better proof than the ticket,' he answered as he wrapped the shoes up and gave them to Mr Smith