A grandfather was delivering his grandchildren to their home one day when a fire truck zoomed past.

Sitting in the front seat of the fire truck was a Dalmatian dog.  The children started discussing the dog's duties. 

"They use him to keep crowds back," said one child. 

"No," said another. "He's just for good luck." 

A third child brought the argument to a close."They use  the dogs," she said firmly, "to find the fire hydrants."