"Youth," said George Bernard Shaw, "is a wonderful thing. What a crime to waste it on children." Could he have said the same of a college education?

College education is primarily targeted at young people -- who often don't appreciate it till they've done time in the school of hard knocks. Perhaps, then, there's no better time than now for research student Seiji Tokita to be in school. He is 74 years old.

A biology researcher at Tokyo Metropolitan University, Tokita broke with common practice by starting college at 61, after he retired from his banking job of 37 years.

For this soft-spoken man, who wears a hearing aid, going to college was the fulfillment of a decades-old dream -- a dream he'd put off since the chaotic days following World War II, when he grabbed one of the few available jobs . . . and just stuck with it.

"In the early years of my working career, I would fantasize about going to school. But as time passed those hopes faded," recalls Tokita while scrunched between a cabinet of test tubes and a mountain of scientific journals. "Two or three years before I retired, that dream came back."

To realize his dream required hard, hard work. After all, one doesn't simply waltz through the gates of higher learning after being away from the school system for almost 40 years.

Tokita spent more than two years poring over textbooks to prepare for the achievement exam required by national colleges, the dreaded senta shiken (center test, named after the National Center for University Entrance Examinations) that keeps youngsters in the thrall of cram schools for much of their adolescence. Tokita then had to clear Tokyo Metropolitan University's own entrance exam.

Having cleared those hurdles, Tokita spent five years as an undergraduate and two more to earn his master's. A glutton for punishment, he went on to earn his doctorate over three more long years. Today, he spends nine hours a day observing the mechanisms by which samples of microscopic swamp life draw energy from light to grow.

Academia took some getting used to at first. Though none of his fellow students -- most of them a mere third his age -- brushed him off outright, they didn't exactly welcome him with open arms either.

"There was some resistance both ways," Tokita confides, as one studious twentysomething fusses over lab equipment nearby. "They saw this old man; I saw a patch of very green saplings. I was worried they disliked me, but eventually we all started inviting each other to go drinking, and the ice melted."

Earning three academic degrees is an impressive feat for anyone. But pulling it off at Tokita's age put him in especially rare company.

"It's a trial," said Tokita. "My memory just isn't what it used to be. I forget even some things I thought I'd learned cold."

According to government figures, among the 609,287 freshmen at Japanese colleges this year, only 1.1 percent finished high school more than four years ago. (The government doesn't track undergraduates by age.) Only 0.3 percent of graduate students across Japan, meanwhile, are older than 61. In his 12 years at TMU, Tokita has only met one other retiree among his classmates.

That's not to say, however, that middle-aged and elderly Japanese aren't busy broadening their horizons outside the four walls of a conventional classroom.

For one, there are about 25,000 people older than 50 tuning in to radio and TV college courses on everything from English to economics -- as part of the government's Shogai Gakushu (Lifelong Learning) program that resembles adult-instruction methods in the United States and Europe. Many of them earn bachelor's degrees. Also, initiatives begun this year include programs in which seniors share their life experiences with children or don work gloves to spruce up the environment.

As for Tokita, he hopes his own research into photosynthesis will some day come in use, say, for engineers looking to nature for hints on how to improve solar-power cells. But he has no illusions of ever becoming a post-doctoral celebrity. For him, as for most seniors who continue to learn, it is more about using challenges to inject life into an aging frame.

"Going to college, studying with young people, that makes you younger," he says with a broad smile. "I'll stay at this until my professor tells me, 'Enough is enough." '