“It is my decision,” I say. “I decided to do it.”

“Well… okay. I hope you got some good advice,” he says.

“Yes,” I say. I do not say from where.

“So — you have the day off? Or you’re leaving today? Where is this treatment going to be given?”

“I do not have to work today. I cleaned out my desk yesterday,” I say. “The treatment will be given at the research clinic, at the campus where I work but in a different building. It starts Monday. Today I have nothing — I think I may go up to Harper Falls.”

“Ah. Well, you take care, Lou. I hope it works out for you.” He thumps the roof of my car and walks away.

I am not sure what it is he hopes will work out for me: The trip to Harper Falls? The treatment? I do not know why he thumped the roof of my car, either. I do know that he doesn’t scare me anymore, another change that I made on my own.

At the park, I pay the entrance fee and stop my car in the empty parking lot. Signs point to different trails: TO THE FALLS, 290.3 METERS. BUTTERCUP MEADOW, 1.7 KM. JUNIOR NATURE TRAIL, 1.3 KM. The Junior Nature Trail and the Fully Accessible Trail are both asphalt-surfaced, but the trail to the falls is crushed stone between metal strips. I walk down this trail, my shoes scritch-scritching on the surface. No one else is here. The only sounds are natural sounds. Far away I can hear the steady humming roar of the interstate but closer at hand only the higher whine of the generator that powers the park office.

Soon even that fades away; I am below a ledge of rock that blocks the highway sound as well. Most of the leaves have fallen from the trees and are sodden from yesterday’s rain. Below me, I can see red leaves glowing even in this dull light, on maples that survive here, in the coolest areas.

I can feel myself relaxing. Trees do not care if I am normal or not. Rocks and moss do not care. They cannot tell the difference between one human and another. That is restful. I do not have to think about myself at all.

I stop to sit on a rock and let my legs hang down. My parents took me to a park near where we lived when I was a child. It, too, had a stream with a waterfall, narrower than this one. The rock there was darker, and most of the rocks that stuck out were narrow and pointed on top. But there was one that had fallen over so the flatter side was on top, and I used to stand or sit on that rock. It felt friendly, because it did not do anything. My parents didn’t understand that.

If someone told the last maples that they could change and live happily in the warmer climate, would they choose to do it? What if it meant losing their translucent leaves that turn such beautiful colors every year?

I draw in a deep breath and smell the wet leaves, the moss on the rock, the lichens, the rock itself, the soil… Some of the articles said autistic persons are too sensitive to smells, but no one minds that in a dog or cat.

I listen to the little noises of the woods, the tiny noises even today, with the wet leaves mostly flat and silent on the ground. A few still hang and twirl a little in the wind, tip-tapping on a nearby twig. The squirrel’s feet, as it bounds away, scritch on the bark as it catches and releases its footholds. Wings whirr, and then I hear a thin zzeeet-zzzeeet from a bird I never actually see. Some articles say that autistic persons are too sensitive to small sounds, but no one minds that in animals.

No one who minds is here. I have today to enjoy my excessive and unregulated senses, in case they are gone by this time next week. I hope I will enjoy whatever senses I have then.

I lean over and taste the stone, the moss, the lichen, touching my tongue to them and then, sliding off the stone, to the wet leaves at its base. The bark of an oak (bitter, astringent), the bark of a poplar (tasteless at first, then faintly sweet). I fling my arms out, whirl in the path, my feet crunching now the crushed stone (no one to notice and be upset, no one to reprimand me, no one to shake a cautionary head). The colors whirl around me with my whirling; when I stop they do not stop at first, but only gradually.

Down and down — I find a fern to touch with my tongue, only one frond still green. It has no flavor. The bark of other trees, most I do not know but I can tell they are different by their patterns. Each has a slightly different, indescribable flavor, a slightly different smell, a different pattern of bark that is rougher or smoother under my fingers. The waterfall noise, at first a soft roar, dissolves into its many component sounds: boom of the main fall hitting the rocks below, the echoes of that blur that boom into a roar, the trickles and splatters of spray, of the little falls, the quiet drip of individual drops off the frost-seared fern fronds.

I watch the water falling, trying to see each part of it, the apparent masses that flow smoothly to the lip and then come apart on the way down… What would a drop feel as it slid over that last rock, as it fell into nothingness? Water has no mind, water cannot think, but people — normal people — do write about raging rivers and angry floodwaters as if they did not believe in that inability.

A swirl of wind brings spray to my face; some drops defied gravity and rose on the wind, but not to return to where they were.

I almost think about the decision, about the unknown, about not being able to go back, but I do not want to think today. I want to feel everything I can feel and have that to remember, if I have memories in that unknown future. I concentrate on the water, seeing its pattern, the order in chaos and chaos in order.

Monday. Nine twenty-nine. I am in the clinical research facility on the far side of the campus from Section A. I am sitting in a row of chairs between Dale and Bailey.

The chairs are pale-gray plastic with blue and green and pink tweedy cushions on the back and seat. Across the room is another row of chairs; I can see the subtle humps and hollows where people have sat on those chairs. The walls have a stripy textured covering in two shades of gray below a pale-gray rail and an off-white pebbly covering above that. Even though the bottom pattern is in stripes, the texture is the same pebbly feel as the one above. Across the room there are two pictures on the wall, one a landscape with a hill in the distance and green fields nearby and the other one of a bunch of red poppies in a copper jug. At the end of the room is a door. I do not know what is beyond the door. I do not know if that is the door we will go through. In front of us is a low coffee table with two neat stacks of personal viewers and a box of disks labeled: “Patient Information: Understand Your Project.” The label on the disk I can see reads: “Understanding Your Stomach.”

My stomach is a cold lump inside a vast hollow space. My skin feels as if someone had pulled it too tight. I have not looked to see if there is a disk labeled: “Understanding Your Brain.” I do not want to read it if there is one.

When I try to imagine the future — the rest of this day, tomorrow, next week, the rest of my life — it is like looking into the pupil of my eye, and only the black looks back at me. The dark that is there already when the light speeds in, unknown and unknowable until the light arrives.

Not knowing arrives before knowing; the future arrives before the present. From this moment, past and future are the same in different directions, but I am going that way and not this way.

When I get there, the speed of light and the speed of dark will be the same.