Frank Burd hadn't heard the news about the George Washington High School teacher pummeled this week by three students, being held down and punched in the face, in a dispute over a cellphone.

But his reaction was visceral.

"Oh, my God, a concussion is serious," Burd said Wednesday. "I feel so much for this guy. One minute, everything is normal, and the next, you're in the hospital."

Burd, a former math teacher at Germantown High School, has been there - attacked in 2007 by students angry that he had tried to confiscate an iPod. He suffered a broken neck and a brain injury that has divided his life into before and after.

The Washington teacher, whom Philadelphia School District officials have not named, is expected to recover from his concussion, his bruising, his badly swollen face. He wants to go back to work.

Burd, whom doctors said came close to being paralyzed, never could.

He is 69 now and will suffer from the aftershocks of his injury - post-traumatic stress, memory issues, concentration problems, depression, most recently vertigo - for the rest of his life.

"I'm overwhelmed by my fears," he said.

Burd remains sharp in conversation, keenly interested in the goings-on of the world around him, even if he no longer actively seeks them out.

"I don't want to read bad news," he said. "It's too upsetting."

He had heard that the climate at Washington had deteriorated. Always an avid photographer, Burd has fashioned a project for himself - walking the streets of Philadelphia, neighborhood by neighborhood. He rambles armed with his camera, capturing what he sees.

On one walk, in the Northeast not long ago, Burd ran into a former colleague from his now-shuttered school who is teaching at Washington. "He was talking about all the difficulties at Washington now," Burd said.

The Washington attack began Monday, when the assailants burst into a third-period biology class. None belonged in the room; one was shouting about getting his cellphone back from a girl who had just returned to the class.

The teacher inserted himself between the girl and the first male, who allegedly pummeled the man while the other two males held the teacher's arms down.

The three teens face aggravated-assault charges and possible expulsion.

District officials removed Washington principal Gene Jones hours after the attack.

Burd was most concerned with the teacher. He identifies with the instinct to protect students.

"I would have done the same thing," Burd said. "I would try to insert myself between the two students. Nine out of 10 times, the situation defuses."

Burd loved his job, telling people he taught kids, not math. But conveying Algebra 2 to students who can't divide two numbers is a challenge, he said, and he knows conditions remain challenging.

Tough, he said, has been the constant.

Even when Burd started teaching, in 1968, he entered a program for interns at Roosevelt Junior High in Germantown. One of his colleagues was newly out of the armed forces, just back from war.

"He lasted about two weeks," Burd said. "When he left, he said, 'Teaching in Philadelphia is harder than Vietnam.' "

For Burd, teaching at a school like Germantown was almost a badge of honor, because it was difficult, and because what happened there mattered so much to how students' lives turned out.

Part of the problem, Burd said, is the way the city's comprehensive high schools have been left to languish, a sentiment supported in a research report released this week.

In the last decade, the city has largely focused on magnet, charter, and specialty schools. The 19 comprehensive high schools attended by most city students, already vulnerable, have absorbed the brunt of the budget cuts.

They are the schools that must accept all students regardless of their needs.

Often, Burd said, a few troubled students ruin things for the rest.

"These are the leftover kids, the kids who didn't get into other schools," Burd said. "And there are so many good kids, kids who are just as bright as anybody else."

Burd has long been curious about his attackers, wishing them well and hoping their lives straightened out.

The Washington teacher's attackers should face meaningful consequences, Burd said, but people must not lose sight of students' needs.

"The question is: How do we help them? They need education," Burd said, "not a situation where they come out angry."