At the end of a visit to Amsterdam, a friend borrowed an old suitcase from his hosts to carry home his souvenirs. At the airport, however, a customs officer subjected our friend’s luggage to a thorough search and even sent for a drug-sniffing dog. Sure enough, the dog entered the area, headed straight for the borrowed bag and went into a frenzy. The customs officer now intensified his search, but ultimately he found nothing.

After arriving home, the young man immediately phoned his hosts and told them how puzzled he’d been by the dog’s behavior.

“Perhaps,” the owner of the suitcase said, “it was because that’s the bag our cat usually sleeps in.”