Emergency Housecall

A doctor answered his phone late in the evening and heard the familiar
voice of a colleague on the other end of the line.

"We need a fourth player for poker," said his friend.

"I'll be right over," whispered the doctor.

"Where are you going at this hour?" demanded his wife as he was pulling
on his coat.

"I'm sorry, honey," he replied, "but I have an emergency call."

"Is it serious?" his wife asked.

"Oh yes, very serious," said the doctor gravely. "In fact, there are
three doctors there already!"