How many times have you seen a man on a steam grate dressed for winter except for his swollen bare feet? Everyone collects coats, but who thinks to give socks?

And yet doctors and homeless advocates say the feet suffer the cruelest fate of life on the streets.

Spending day after day in wet, sweaty, or soiled socks leads to fungus, bacterial infections, and gangrene. Wearing no socks or plastic bags hastens diabetic neuropathy and frostbite, which alcoholics or addicts may not realize they have until it's too late.

"The feet are a portal to the rest of the body," explains Kathya Zinszer, chair of Temple University's School of Podiatric Medicine, who runs clinics at area shelters.

Lara Carson Weinstein, a physician at Jefferson Medical College who works with Project H.O.M.E., tells me she treated "at least seven" homeless patients in the past year who lost toes or feet to the streets.

The sobering statistics led Chestnut Hill College professor Tom Costello to launch the aptly named nonprofit The Joy of Sox. Its mission is simple: Put new, clean socks on cold, aching feet.

An unexpected awakening

Costello, an engineer-turned-adjunct business professor, hardly fits the profile of the nonprofit's "Chief Sock Person." A born do-gooder, he's not.

"I was," he admits, "a white suburban boy afraid of homeless people." For reasons Costello can't quite explain, he had an "Oh, my God, we have to do something!' " reaction upon learning of transiency's toll on the extremities.

Horrified and humbled, "I went online and reserved the domain name"; Then he sought 501(c)(3) status and Googled sock manufacturers for castoffs.

Tommy Evans barely remembers the conversation, but the CEO of Alabama Wholesale Socks - a "Christ-owned and Christian family-operated" company - happily put 750 pounds of seconds on a truck to Costello's house in Radnor.

"We always have products we can't sell," Evans tells me by phone. "Why not give them away?"

Socks in hand, Costello found energetic assistants in Chestnut Hill freshmen, who are required to perform community service and read The Soloist, journalist Steve Lopez's riveting book about befriending a homeless schizophrenic musician in Los Angeles.

The touch, the feel of cotton

KarlaAne Klouda and Luciana Texidor were among the 18 students who showed up last week for the inaugural sock-sortathon. They dove into the monotonous task, digging through a mountain of mostly white cotton. Matched pairs got folded; orphans with holes, tossed.

Texidor, a psychology major from New York, choked up after finding a lavender baby sock. "This," she says, "reminds me of how much I take for granted."

When Nick Johnson debated whether to discard socks imprinted with the Confederate flag because they might offend the recipients, Darrell Robinson nodded. An Olney High graduate, Robinson has a vivid image of the homeless.

"I see them in Hunting Park and at SEPTA stations," he shares. "They either don't have socks or they've got shoes with holes. That must be awful in the cold weather."

Hours later, 1,620 pairs had each been tied with purple and gold ribbon. Why the fancy finishing touch? Costello grins: "It was my wife's idea to make them seem like a gift."

The next day, the professor dropped off 540 pairs to St. Francis Inn Ministries in Kensington, which each month feeds and clothes up to 400 struggling seniors, families and homeless men.

"Our guests can't afford to live indoors and eat," explains Brother Fred Dilger. "They don't have discretionary funds for clothing."

Costello may team up with Zinszer to distribute the remaining 1,080 pairs this winter. Coats and hats are holiday staples, Zinszer acknowledges, but her patients' lives depend on a charity rarity: "a six-pack of clean cotton socks."