Carrying a mug of coffee, the man in the plaid shirt marched up to the microphone. A guitar was slung over his shoulder, and he strummed it once, in G major. That was all it took.

Play-Doh was set aside. Charlie Brown books were put down. Forty young patients gazed front and center in the main lobby of Children's Hospital. With a shy smile, folk singer Tom Paxton began an old favorite: "The fox went out one chilly night Prayed to the moon for to give him light He had many a mile to go that night Before he reached the town-oh

It was the morning before Thanksgiving, and Tom Paxton would say later that this was his way of heeding the special message of that special holiday. For 45 minutes (and no money), Paxton sang songs about animals, love, life and kids to the most critically ill patients in Children's Hospital.

On the day before Thanksgiving, Children's always tries to grant weekend-long passes to as many patients as it can. "We think that a hospital is a lousy place to grow up, and we think it's a lousy place to spend Thanksgiving," says Dr. Robert H. Parrott, the director at Children's. "So if we can possibly send a child home at this time of year, medical circumstances permitting, we do it."

For these 40 kids, Children's couldn't do it. It was obvious why.

To Tom Paxton's right was Larry. A cast covered his right leg. A pin had been driven through his right knee. He was in traction. The word was that he might not walk again.

Straight ahead was Patricia. Her skin was yellow. Kidney trouble, the nurse said. Bad kidney trouble.

To Paxton's left was a five-year-old boy injured in an accident. He sat in a wheelchair. Once in a while, guided by instinct, he tried to get out. It was then he discovered all over again that he was paralyzed from the waist down.

But Tom Paxton sang of happier places, happier times: We're going to the zoo, zoo, zoo How about you, you, you? You can come too, too, too We're going to the zoo, zoo, zoo

A little boy named Eric, perhaps five, didn't have to be invited to sing along. "Zoo, zoo, zoo," he sang, while he clapped his hands.

Nearby, Patricia kept time by tapping her palm on a bench. Beside her, Alex and his grandmother played pattycake.

And Tom Paxton sang on: I know an old lady who swallowed a fly I don't know why she swallowed a fly Perhaps she'll die

Doctors on their way into surgery heard the music and stopped. They're on a first-name basis with the nurses, who are on a first-name basis with the volunteers, who are on a first-name basis with the patients.

Children's Hospital is that kind of a place.

A custodian walked through the lobby, carrying a dustpan. He, too, stopped to listen for a minute. A boy in a wheelchair smiled at him. He smiled back and asked the boy how he was doing.

Children's Hospital is that kind of a place.

About two-thirds of the way through Paxton's concert, the elevator doors opened and Dr. Parrott emerged.

The morning before, his desk had been piled high with unread journals, half-read reports, unanswered correspondence. Robert Parrott is a busy man.

The pile couldn't have gotten much smaller in 24 hours. But Parrott spent ten minutes in the lobby as Tom Paxton sang about Engelbert the Elephant. He smiled at the children. They smiled back at him.

Children's Hospital is that kind of a place. Froggy went a courtin' and he did go, uh huh Froggy went a courtin' and he did go, uh huh Froggy went a courtin' and he did go He looked all over this little old world Uh huh, uh huh, uh huh

Tom Paxton ended his concert by toasting the kids with his coffee cup. They gave him a round of applause in return. Then he did the rounds -- a "name" entertainer who usually plays coffee houses at midnight schmoozing with sick little kids at 11:30 a.m.

They loved him.

"You sang good," said Larry. Paxton thanked him. Whereupon Larry got embarrassed and covered his face with a pillow.

"How come you didn't sing 'Old McDonald?' " Eric asked him. "Ran out of time. Sorry," said Paxton. He shook Eric's hand by way of apology. Eric beamed.

"I hardly ever do this," said Paxton, as he bundled up to leave. "I'd like to do it more. They're beautiful, beautiful children. And this sure looks like a nice place."

No argument about that, Tom. No argument whatsoever.

To contribute to the campaign:

Make a check or money order payable to Children's Hospital and mail it to Bob Levey, The Washington Post, Washington, D.C., 20071.