As ham sandwiches go, it was perfection. A thick slab of ham, a fresh bun, crisp lettuce, and plenty of expensive, light brown, gourmet mustard. The corners of my jaw aching in anticipation, I carried it to the picnic table in our backyard, picked it up with both hands but was stopped by my wife suddenly at my side.

''Hold Johnny (our six-week-old son) while I get my sandwich,'' she said.

I had him balanced between my left elbow and shoulder and was reaching again for the ham sandwich when I noticed a streak of mustard on my fingers. I love mustard. I had no napkin. I licked it off. It was not mustard. No man ever put a baby down faster. It was the first and only time I have sprinted with my tongue protruding. With a washcloth in each hand I did the sort of routine shoeshine boys do, only I did it on my tongue. Later (after she stopped crying from laughing so hard) my wife said, ''Now you know why they call that mustard 'Poupon.'''