When Lynn Prothro took American history from Fulton Davis at Bethesda-Chevy Chase High School, she started the first semester by making consistent Ds.

"But something happened - Fulton twisted me," she said. By the end of the year, Prothro was making As. "I just liked him so much that I began to feel guilty after a while about not doing the work," she said. "He was the only teacher I ever called at home for help."

Prothro is one of many Bethesda-Chevy Chase graduates and students mourning this week for a man they say was one of the most creative and personable teachers they have known.

Davis, 36, a teacher at Bethesda-Chevy Chase for 15 years, died in a automobile crash Tuesday on Layhill Road in Bethesda. Also killed was Randolph Kent Simon, 17, of 11712 Tree Lawn Dr. in Ashton.

A passenger in Simon's car, Effron Close, 19, of 1708 Chapel Rd., Silver Spring, remained in critical condition yesterday at George Washington University Hospital with head and abdominal injuries.

Montgomery police said the crash occurred when the car driven by Simon, a student at Sherwood High School, crossed over the center line of the narrow, two-lane road to pass a truck. Police said he ran head-on into a station wagon driven by Davis.

Simon, who lived with his mother, Peggy Simon Arnold, had just finished his junior year at Sherwood. His father, S. Lester Simon of Baltimore, said he played guitar and tennis, and was interested in math and science.

The students who knew Davis say that although he taught history for 15 years at Bethesda-Chevy Chase, his first interest was in working directly with students. He had given up his history job recently to pursue student counseling full time.

After working on a part-time basis at Bethesda-Chevy Chase while attending Bowie State College the past year, Davis planned to start full-time counseling at Wood Junior High School next fall.

"He just vibrated with kids, he liked them intensely, and he gave all he had to them," said Ed Schneck, a science teacher at B-CC.

When he was not teaching history, his friends say, Davis was usually out in his office or home late at night, to the faculty he worked with in developing new teaching programs, to the special classes that he took back-packing or camping.

As a teacher, Davis worked with Schneck to develop a special curriculum for gifted and lagging students. Between 1970 and 1973, 120 Bethesda-Chevy Chase students were assigned to the "school within a school," which abandoned rigid time and subject scheduling for a flexible, comprehensive program in math, science, English and social studies.

"Mr. Davis was just great in that program," said Betsy Jay, who spent a year in the school within a school. "He used to set up the class to reenact the negotiations before the Treaty of Versailles," she remembered, "and we were supposed to work together to come up with a plan for world peace."

Jay said that Davis' exams often took the form of impromptu personal discussions that would stretch for hours. The students in the program also went on camping trips to the Appalachian Trial, she said, and Davis' house, then across the street from the school, became a regular gathering place.

"you could go over to talk to him and he always welcomed you, he always just listened," said Dorothy Durvall, who studied under Davis for three years.

"And now for him to die so suddenly, well, everybody is just crushed. I've talked to other students and everybody is just completely taken back."

Rene Metzger, a senior at B-CC, said students are collecting money for a scholarship fund for Davis, who is survived by his wife, Sharon, and a 4-year-old son.

Funds are also being solicited for a Randy Simon scholarship for science students. A memorial service will be held for Simon Friday in the Sherwood High School Auditorium at 3 p.m.