From the outside, you’d guess that Robert Greenspan’s garage contained golf clubs, tools, bikes, a sports car, dog food. And you’d be right, partially. But half of the space is filled with electric chairs, chastity belts, and eyeball massagers.

Dr. Greenspan, a kidney specialist in Alexandria, started collecting medical antiques in 1974 when he unearthed a first-edition textbook by Dr. William Osler, a father of modern medicine, in a bookstore. This year Greenspan self-published a book, Medicine: Perspectives in History and Art, based on his collection, which has taken over half of his two-story garage and a room in his house and is one of the world’s strangest and most extensive.

A surgical set from the 1600s lies across the room from the Peruvian skull of one of the first brain-surgery patients. A copy of Thomas Eakins’s “The Gross Clinic” hangs on a wall with the very scalpel depicted in the painting.

“You’ve heard the phrase ‘don’t bite the bullet?’ Well, here’s the bullet,” Greenspan says, holding a tooth-marked slug, the kind Civil War soldiers would bite during surgery to keep them from screaming.

Medical history teems with imprudence and superstition. There are cabinets full of amputation saws, leech jars, apothecary potions, a shrunken head. There are two working electric chairs; electric therapy was once thought to heal everything from constipation to impotency. His daughter, Emily, kept one in her Harvard dorm room while he worked out a way to get it home.

As his collection grows, Greenspan is running out of room. “My wife only gives me certain spaces,” he says. But he has secret plans for the other side of the garage. “I’ve snuck a Kellogg workout horse over there, the same kind used in the exercise room on the Titanic.”