Astroll through the Presidential-portrait wing at the National Portrait Gallery, in Washington, D.C., is, among other things, a game of Now You See It, Now You Don’t. In the beginning, not a whisper of a whisker—not on Washington, Adams, Jefferson, Madison, or Monroe. In the early nineteenth century, John Quincy Adams and Martin Van Buren change things up with fluffy muttonchops that drift like snow from ears to laugh lines. Otherwise, it’s a series of glabrous, faintly pink visages until you get to Abraham Lincoln. He adopted a beard after Grace Bedell, an eleven-year-old girl from Chautauqua County, New York, wrote him in October, 1860, urging him to let his whiskers grow: “All the ladies like whiskers and they would tease their husbands to vote for you and then you…