Fred Stuman, accountant, arrived home after a hard day's work and long commute from the city. He kissed his wife and nine-month-old daughter, fixed himself a drink, then sat down in the den to relax and read the evening paper.

Fred knew his daughter had been teething lately. This was the main reason, he supposed, for her bad mood the day before. Yesterday, she had been cranky and crying, drooling excessively and unwilling to eat.

But tonight Trish seemed in fine spirits as she happily crawled from room to room, babbling inquisitively, exploring every household artifact in sight.

After a while, Fred put aside the stress of his corporate workday and sought Trish for a little old-fashioned father-infant entertainment. Actually what Fred had in mind was a toned-down game of "Horsey." A little tired, he could have easily opted for a less aerobic activity. But around this house, especially before bedtime bottle, Horsey absolutely reigned as the infant sport of choice. No matter how many times they played it every week.

So Fred bounced little Trish on his lap, tentatively at first, then faster and faster, listening to her timid giggles turn to wild squeals. She obviously enjoyed having time with her father.

Between bounces Fred started thinking about Trish's teething pains and wondered if she had a new tooth to go with a trio fully grown-in, it seemed, for weeks now.

"Let me see those toothies," he said, tickling her until she laughed even harder, mouth open wide.

Fred looked inside. Fred tickled. Trish laughed and laughed. Then lunging forward, without warning—except for a malevolent flash in her eyes—Trish snatched Fred's glasses, screamed, and bit him viciously on the nose.