So the college professor, eager to help his school maintain assured mutual destruction with its old rival down the road, gave Boley Bruiser, the behemoth tackle, one last chance to muster a passing grade in Science 101. "What is mankind's greatest scientific advance in this century?" the professor asked Boley, who took another bite out of a tree.

"Gimme hint," Boley said.

"The atom," the old man said in a whisper, looking over his shoulder lest an English Lit teacher pass by.

"Think it was the thermos bottle," Boley said.

The professor blinked. "Even with nuclear energy, you say 'the thermos bottle.' Why do you say that?"

"'Cause it keep hot things hot and cold things cold," Boley said.

"With the growth of microtechnology, you still say the thermos bottle," the professor said sadly. "Just because it keeps hot things hot and cold things cold."

"But how," Boley said, "do it know ?"

Guardians of the journalistic flame will recognize these first few paragraphs as a composite/fabrication/lie (choose one). I beg forgiveness, for I have seen Julius Erving at work again and I am left with the question, "But how do he know ?"

How does the Doctor know to fly? To float? If levitation is against the law of gravity, someone better get Isaac Newton on the phone because Julius Erving has caused apples to fall up into trees.

Heaven knows, even Boley Bruiser could name a dozen reasons the National Basketball Association is in trouble.

The only reason that matters is this: there aren't enough Julius Ervings.

In a league stuffed with wonderful athletes, the Doctor stands alone, the most elegant of the elegant, a man created to play basketball. Yet he brings more than his talent.He brings honesty. For a day's pay, he gives a day's work. If even half the NBA players could be vaccinated with the work-ethic serum that courses through Erving, the leaugue wouldn't have to answer questions about diminishing attendance and vanishing TV deals.

In the third game of the current Philadelphia-Boston series for the Eastern Conference championship, Erving was the key player for a reason you would never expect. He played defense. He played against Larry Bird, who had scored 33 and 34 points in the first two games. Nitpickers probably said of Michelangelo that he was pretty good on ceilings but so-so on walls, and of Erving they have said, "So he can fly. But can he deny the ball to Bird?"

Dr. J. did his 360-degree thing, flying at the hoop in one direction and spinning away, only to scoop up a shot left-handed. He had his 22 points, some on dunks made as he passed through the sky over the Spectrum. All that, we expect. And by games's end, when Philadelphia had won by 10 points and Bird managed 22 on eight-of-16 shooting, the answer to the nitpickers' question was clearly yes. Yes, Erving can play defense.

For the first two games of this series, the 76ers had entrusted the defense of Bird to Bobby Jones and Caldwell Jones, with an occasional assist from Erving. In the second game, Bird made 14 buckets, seven from outside 20 feet. That long-range accuracy moved the Philadelphia coach, Billy Cunningham, to assign Erving to play defense against Bird in the third game.

Now a coach's order in the NBA is not the same as, say, Bobby Knight's orders at Indiana University. A pro has his pride, you know, and some of these fellows being paid hundreds of thousands of dollars won't take an assignment bound to make them look foolish.

Playing defense against Larry Bird is a certain route to foolishness. He seems ungainly in flight, this Bird. In his dark green Celtic sneakers, and in his flat-foot trot, he appears to be galumphing around in galoshes. His quickness may be lost in appearances, but it is obvious in the open shots he gets and the offensive rebounds he weasels away from men who thought they had position on him.

"Just one on one, Larry is the toughest man in the league to guard," Erving said later. "That's where our good team defense helped tonight."

As Erving overplayed Bird to keep the ball away from him, other 76ers watched that mano a mano in case Bird should slip free to take a pass out of Erving's reach. Then Bobby Jones or Caldwell Jones would come over to help out Erving in this impossible mission he chose to accept.

At this level of play in the NBA, not much separates the teams. The first quarter may have decided the third game here, and Cunningham's decision to use Erving against Bird may have decided the first quarter. In those first 12 minutes, Philadelphia built a 31-20 lead as Bird scored only three points.

"I think they were surprised when they saw me on Larry," Erving said, "especially with me face-guarding him. I tried to deny him the ball that way because in the second game he got going bascially playing a guard position. I didn't want him hurting us again from outside that way."

By using his quickness, Erving kept the ball out of Bird's hands as much as that is possible. Bird took only three shots the first quarter.

"I wasn't in the offensive flow at first," Bird said. "Doc did a great job on me tonight."

"The Celtics waited a long time until they started doing something specifically for Larry," Erving said. "By then we were well into the second quarter, and they were playing catch-up."

It was wunderful, seeing Erving on Bird, with the good Doctor peering through thickets of tall men to see what the genius in galoshes was up to next. At times, in his effort to watch the ball and Bird at the same time, Erving had to turn his back on his quarry; then, to keep track of Bird, Erving would swing a hand around his rear, groping, as a blind man reaches out for a guilding wall.

To show you how tough Erving's job was this night, here is one instant replay:

M. L. Carr has the ball for the Celtics, left side, free-throw line extended . . .Bird is low, right side, six players between him and Carr, Erving turned sideways to see both Carr and Bird . . . Suddenly, Bird flashes past Erving, three steps, four, leaning into a turn off a pick at the free-throw line as he takes the pass from Carr . . . Erving, a quarter-step behind, is yet at Bird's hip, close enough to worry anybody . . . Anybody except, Bird, who with one dribble goes up from 13 feet, drifting away from the hoop, and banks in two points.

Only one other basket was more astounding. At halftime, they brought fans out of the stands to try half-court shots. A bearded fellow named Louie, throwing the ball baseball-style, made his shot and won a vacation for two in the Bahamas.

"Who are you going to take with you on the vacation trip?" the public-address announcer said.

"My wife," Louie said.

The crowd of 18,000 people booed.