George Tokieda, who died Saturday at age 63, was a much-beloved teacher at Manhattan’s Brearley School, where he enthusiastically taught science to generations of girls and young women.

“George Tokieda was a treasured master teacher at Brearley. An educator who never stopped learning himself, he ignited the students’ passion for science,” said Stephanie Hull, head of the Brearley School.

“‘You don’t have to spend money on materials,’ he always said,'” according to Mary Feldtmose, a fellow Brearley science teacher. “You can take a walk in Central Park and find a hundred things to investigate with your child.”

Tokieda grew up in Clewiston, Fla., where his father’s job managing a nursery gave him a firsthand view of botany from an early age. He recalled growing up on the southwest edge of Lake Okeechobee, “where every pond of water had fish in it, and the whole food chain, from rabbits to bobcats, was practically at my parents’ door.”

As the son of Japanese parents during World War II, Tokieda saw his family investigated for loyalty by the FBI, but they were never interned, according to Tokieda’s daughter, Kathryn. A nurturing high school teacher helped Tokieda to apply to Princeton, where he majored in English.

Tokieda began his teaching career at the William Penn Charter School in Philadelphia, then moved to New York, where he took a teaching position at the Buckley School. He joined the Brearley science department in 1975. He served as head of the science department for a decade, starting in 1977. He also volunteered for the Children’s Storefront School and consulted for the Children’s Museum, in Phoenix.

Karen Nedbal, head of Brearley’s science department, said, “George believed in…doing real science from the beginning with our youngest students.”

At the heart of science teaching at Brearley is the “Investigation-Colloquium Method,” which encourages student participation. “First-graders write lab reports just like sixth-graders,” Tokieda wrote in a Brearley newsletter. He considered such instruction “the key not just to becoming scientifically literate, but a part of growing into good and decent and feeling human beings.”

During an unplanned trip to the hospital in the early 1990s, Tokieda was surprised to find out that one of his first Brearley students, Deborah Ascheim, was assigned as his emergency room doctor. Later, as he began to deal with the congenital heart failure that would eventually lead to a heart transplant and then take his life, Dr. Ascheim became his cardiologist.

“It was ironic for the teacher-student relationship to be flipped,” said Dr. Ascheim, who vividly recalled dissecting a cow’s eyeball under Tokieda’s supervision in the late 1970s. Dr. Ascheim got to know her old teacher better as he waited for a new heart in the hospital in late 1997, and then later when he returned for follow-up procedures. He insisted on detailed scientific explanations of his condition.

“I’ve never seen anybody fight like he did,” Dr. Ascheim said. “And it was always, ‘How am I going to get myself back to teaching?'” Having taught one of Dr. Ascheim’s daughters, Tokieda had recently asked her permission to teach another when she entered kindergarten in the fall.

Although he was sidelined intermittently by illness, Tokieda was back in school last Thursday. His death came as a shock. “We all got spoiled by how he was the Eveready Bunny,” Dr. Ascheim said.

George Zenbei Tokieda

Born August 20, 1941 at Clewiston, Fla.; died March 5 at The New York Hospital-Cornell Medical Center of septicemia; survived by his wife, Margaret Quigley Tokieda, his children, Kathryn J. Tokieda and Charles P. Tokieda, his mother, Anna Imperial, and a brother and a sister.