My knees were so often marked by scabs that they still look naked without them, and when I see someone with a skinned knee, I feel a warm fellow-feeling, hearty and a little envious. I like the sheer page-white of the first instant. Then the measles of blood that decorate the white, then the slow, rich flow of blood down my leg, a warm thick worm. It's comforting, almost like lotion. After the blood stops, I like the thick slippery translucent skin of pink stuff, sticky as fresh Jell-o, coming up in stuck-to-finger-tip peaks when you touch it. This goes stiff, like a bit of cardboard stuck to the skin, then even stiffer. It is as if I weirdly grew a shard of crockery! I like the feeling of the scab stretching when I bend my knees, and bunching when I straighten them. Repeated, this action wears creases in the scab, which eventually cracks. Then blood and pain again.

Watching films of volcanoes in school, I recognized myself: the black crust cracked, the hot-orange lava welled up, darkening, and hardened into new crust. I was planetary!

I haven't mentioned the sweet, rich smell of the open cut. (I'd sit hugging my legs, and bow my head to smell my knees with a private smile.) Or how the scab would soften in the bath, like an old newspaper in the rain. Or discussed prying at the sides of the scab, which were raised like a dinner plate's, only to find it was still stuck on by a dot of raw meat in the middle.

Hairs grow up through the scab, like blades of grass through the old doormat we left to rot in our hideout. The hairs sew the scab to the skin underneath. The scab breaks up but hangs on. You scratch it off in bits. Underneath the new skin is hard and white.

When I was five I ran whooping down the steep slope from the yard to the road in Falls Church, Virginia, accompanied by skipping, rolling, half-airborne pebbles and crumbs of dirt, and the moving surface got whisked out from under my by some trick and I found myself sliding on both knees down the slope, until I tumbled over the curb into the road. There was no one to see what a terrible thing had just happened to me, so I didn't cry, just got up, shocked and lonesome under the happy Crayola sky. I toiled, suddenly small, up the long, long driveway. I realized something about time: that the moment was lost forever when I could have righted myself and skidded down in triumph. The present stretched out gravelly and mundane as a driveway and for the whole length of it I was bleeding and a blunderer. At some point I would reach the house and my mother would comfort me for my bleeding knees, but I already no longer needed comfort. That would also come too late.