Art teacher Marita Fitzpatrick dimmed the lights Wednesday morning. Anything to cool her basement classroom. Her 25 students, mostly juniors, at Bodine High School for International Affairs, a magnet school in Northern Liberties, slumped at their desks.

Normally, a class of 16-year-olds a few minutes before dismissal would be antsy, chatty, eager to leave. Now, Fitzpatrick could barely get them to keep their heads up. It was just too hot.

And so, Fitzpatrick began to read them a letter she had written to the newspapers, after my colleague Kristen A. Graham reported about the lack of air-conditioning in Philly's public schools — and the early dismissals it has forced. Wednesday was one of those days.

"As someone who has worked in these old buildings for close to 20 years," the veteran art teacher read, "I have watched everyone in them dealing with some issues that elsewhere would be unacceptable."

No air-conditioning in the summer. Overloaded heating systems in the winter. The leaks. The moldy walls. The rodents.

And that's on top of the greatest hits: understaffed libraries, under-supplied teachers, disappearing nurses, and indifference from the state.

Besides that, so many kids, including some of Fitzpatrick's, will go back to homes in a deeply poor city, after-school programming cut to the bone, deep housing inequity, and an unimaginable number of shootings targeting children like them.

And on days like this, the reality is that we're content to let them sweat like jockeys trying to make weight. With the average city school built in the late 1940s, many schools are just too old for an air-conditioning system.

Even when enterprising parents and teachers raise money for window AC units, often schools' electrical systems are too feeble to handle the extra wattage, Graham reported.

Summers are only getting hotter — today's sixth graders experience three more days a year above 90 degrees than they did when they were born. And as my colleague Frank Kummer reported earlier this summer, Philly's impoverished and neglected neighborhoods can run as much as 20 degrees hotter than leafy, wealthy neighborhoods like Chestnut Hill.

Perhaps we should update the old adage: In Philly, you don't slip from the frying pan to the fire. You walk from the classroom to the block.

Places that are supposed to be havens are now hotboxes.

As Fitzpatrick hinted, this wouldn't be tolerated in the suburbs. Like everything with our school system, we accept that allowing our children to suffer in stifling heat is just how things go for the kids of our schools, who are mostly children of color.

And as Councilwoman Helen Gym pointed out, nothing is an easy fix in Philly public schools. She estimates it would cost $4 million to cool every classroom. But that would be the tab if every school was structurally sound enough to handle an air conditioner. And they're not.

Gym is right to call this a public health crisis: At least 12 students fell ill from the broiling temperatures in schools last week.

Cooling classrooms will likely take city, state and private funding — a long-term solution rather than half-days that keep kids from learning.

Meanwhile, teachers who already have to get creative scrounging classroom supplies are earning their scouting badges just to cool their classrooms. I know of at least one teacher who's jury-rigging a swamp air conditioner — a bucket, some ice, a fan. Relief, certainly, for students sitting two feet away.

And so, on Wednesday, Fitzpatrick read her letter to her super-bright kids, most of them from low-income households, who come to class each day eager to learn, but who have never known a school with an air conditioner or a fully stocked supply cabinet that wasn't the result of a protracted fight for funding.

"They feel powerless," she told me. "They feel like no one cares." Except for the little community within their crumbling building. But  Wednesday, they just felt hot.

The bell rang. They thanked Fitzpatrick. Sluggishly, they filed out.