Pretty soon, artist Tom Green will lose the calluses on his right hand, which he got from years of painting his big canvases on the studio floor.

Sooner or later, he will probably lose the function of his hands altogether. They already seize up badly if he goes outside, and the muscles in his forearms occasionally twitch uncontrollably.

He thinks he has some time. How much, he’s not sure.

Green, 69, the acclaimed Maryland painter of wondrous hieroglyphic and semiabstract art, has amyotrophic lateral sclerosis — Lou Gehrig’s disease, named for the famous baseball player whose life it claimed in 1941.

It is a terminal neurological illness that gradually robs the body of its motor skills. It takes away, in many cases, the ability to walk, talk, stand and even eat, while leaving the brain and senses intact.

It could eventually take Green’s ability to paint, something he has done for most of his life.

And it comes as he is at the top of his form.

“I really feel like I’m doing the best work I’ve ever done,” he said. “In command of my materials, and . . . a kind of conceptual language that I’m comfortable with.”

Now he confronts the climax of a life spent exploring the accidental and intentional in art, with the reality and timing of his death.

“Most people don’t know when they’re going to die,” he said. “I know sort of when I’m going to die. . . . Time is of the essence now.”

“In some ways I’m relieved, because I don’t want to grow old and infirm,” he said. “So I see this as an opportunity to die, which I don’t mind.”

Green, who taught at Washington’s Corcoran College of Art and Design for 40 years, has a unique artistic voice, said Jack Rasmussen, director of the American University Museum, which played host to an exhibit of his art this year.

“He comes a little bit out of the Washington color school,” Rasmussen said of the abstract color painters of the 1960s who were the area’s “first, and only, grab at national attention.”

“He was never really a part of it, but it’s obviously an influence,” he said. Green “always stayed figurative, even at his most abstract. There’s always elements from the natural world — water, trees, sun.”

Over two days last month, Green, his eyeglasses propped up on his head, ambled around his rustic house and adjoining studio in Cabin John, where even the paint-splashed plywood floor is art, and talked about his life, his work and his coming demise.

He appears thin now, compared with a photo taken three years ago. His wife, Linda, said he recently lost 25 pounds. And his black Italian motorcycle sits unused beneath a green tarp in the yard.

But he still has his thick, boyish-looking hair, a sly grin and lots of ideas.

He said he does not think his impending death will influence his art. It might “seep” in here and there, he said.

But he can’t really force himself to address the subject: That would be unnatural — “like an assignment,” he said later.

As for the future, he said he plans to work on a smaller scale. He said he has also been reviewing older paintings he started years ago and realizing, “Oh, my God, I never finished that.”

First signs of the disease

Linda Green said she first noticed two years ago that he began rubbing the tips of his fingers together, and that his jaw would “hang,” as she put it. She thought he had Parkinson’s disease, which his mother had.

As time passed, she noticed that he could not keep up when they took walks around the neighborhood. His driving ability began to slip slightly. Then he messed up a repair job on his motorcycle, she said.

She sensed something was wrong.

He saw a doctor, who said he seemed fine. She had him make another appointment and went with him to report what she was noticing. They were referred to a neurologist, and he was diagnosed as having ALS in July.

The illness — which destroys the motor neurons that carry messages from the brain to the muscles — usually runs its course in two to five years.

Initially, his wife said, they thought they had time before the worst of the illness set in.

“But I think that it’s happening so quickly, that he seems to be losing so much so quickly, that it’s starting to bear down on us a little bit,” she said.

Tom Green often uses a walker or cane to get around. The disease has affected his speech, which is deliberate. And he wears a neck brace to help hold his head up.

But his arms still seem strong, and his sense of humor is intact.

His studio is filled with large colorful paintings leaning against the walls, as well as tools and lumber for stretching canvases.

There are rulers, a staple gun, pocketknife, pliers and a hammer. There is a table filled with containers of paint and brushes lined up like a surgeon’s instruments.

And there is the green-and-white striped beach chair where he sits to scrutinize his work — and think.

Much of Green’s work is on large canvases, 5 by 6 feet or so, that he used to spread on his studio floor.

He would get down on his hands and knees, wearing knee pads — “like I’m scrubbing” — and paint with a half-inch-wide brush.

He worked on the floor so his thin, fast-drying acrylic paint wouldn’t run.

He is left-handed and would balance himself on the canvas with the knuckles of his right hand to avoid putting his palm on the painting. After decades of such work on the coarse canvases, those knuckles have calluses, which he expects to fade.

He said he is not painting on the floor anymore because it’s too hard to get up and down, and uses physical energy he wants to preserve.

One day last month, as light filled his studio and the only sound was that of his hand inching across the paper, he sat in the folding seat of his walker and began a smaller painting that was set on a table.

Normally, he said, he would stand to paint at the table. But he has trouble keeping his balance now, so he must sit.

“My hands are starting to act up on me,” he said, as he put opaque white paint on a black surface. “If I’m out and my hands get cold, they’re really worthless. I come in, and they won’t do anything.”

As he paints, he holds the brush like a pencil. “You see what part of my fingers I use,” he said. “But as these fingers disappear, the dexterity . . . I’m not sure what I’m going to do. . . . It’s almost like I’ve got to change the way I work so I can use a brush . . . like painting a house or something.”

A man’s evolution, in art

Green, who was born in Newark, is the oldest of four children of a printer who moved his family to Maryland when he got a job at the U.S. Government Printing Office in Washington.

He studied art at the University of Maryland and was caught up in the social and artistic tumult of the 1960s.

“It was pre-hippie, but I was kind of like a beatnik,” he said.

At one point, he and his first wife and a friend drove to Mexico in his turquoise ’59 MG sports car. They stayed until the money ran out.

“That’s when I decided: ‘I’m going to be a painter,’ ” he said.

Back home, he began to experiment.

He sprinkled gunpowder on paper and set it afire, just to get a starting point for a painting. “It’s tricky,” he said. You have to be careful not to use too much.

He drew with mustard and pokeberry ink.

“I was trying everything then,” he said. “That was the kind of thing that was in the air.”

He once set up an art installation that included sharpened tree branches he had charred with a blow torch.

Another time, he used a simulated coffin in tribute to his younger brother, Paul, who he said had been shot and killed at age 21 by police in New Mexico in 1971.

The killing, which he described as senseless, left him angry for many years.

But he continued to paint.

He carried black sketch books, filling them with page after page of doodles in black ink, as well as news clippings and hand-drawn calendars. It was a way of recording and testing — “circling” — an idea until he got it right, he said.

He has 18 such volumes stored in a bookcase.

Many of the books contain his glyphs, which look like some lost writing uncovered in the jungle. They also appear in many of his paintings. Although some seem familiar — resembling water, a cat or an eye — they are cryptic.

“You have to accept that these are just alive,” he said. “And they affect you in a nonverbal way. And to me, that’s what keeps them alive. You don’t resolve in your mind what it is.”

Green said that he has loved his life in art.

“I think of it as ultimately a big mystery,” he said. “I was drawn into it, and then I was hooked on it. I sometimes call it a disease. There was no way I could walk away from it. ”

He said one of the hardest things is knowing when a painting is finished. “It’s easy, basically, to start a painting,” he said. “To know when to stop is infinitely harder. You’ve got to decide: Is this complete? Does it have everything that I wanted from it?”

Completing the work of a life is different, he said.

“If I made a mistake on a painting, I could go back into it,” he said. “If I make a mistake in life, it’s a little harder to rewind and straighten it out.”

As the work of art that is Tom Green nears completion, he said he does not care much what is done with his remains afterward.

“I just want to be cremated and thrown to the winds,” he chuckled. “I’m not attached to my physical person. My legacy is in my work.”