At a cocktail reception to open "Civil War Medicine," a new exhibit at the ever-so-curious William P. Didusch Center for Urologic History, located in the Baltimore burbs, onlookers quietly groan as a Civil War surgeon tosses a Union soldier's amputated arm into the piles of bloody body parts littering the floor. Suddenly you're not so drawn to the chips and salsa at the hors d'oeuvre table.

Next, the doctor picks up a long, curved, silver instrument designed for very personal probing, and some of the men among the party guests get a woozy rush.

"Didn't work," announces the physician, Robert Urban, demonstrating battlefield surgeries in the lobby of the American Urological Association headquarters in Linthicum Wednesday evening.

The soldier, a corpse-like dummy attired in a Union blue uniform, lies in a field hospital mock-up of the 23rd Pennsylvania Infantry. Wounded in the belly, he "can't go to the bathroom," says the goateed Urban, who isn't a real doctor -- he just plays one on TV (the Discovery Channel, sometimes) and in battlefield reenactments.

But real doctors -- urologists -- are among the 125 or so guests paying close attention to the procedures. Someone in the crowd deadpans a classic urological prognosis: "If he can't go, he dies."

Dressed in an authentic "blood"-splattered white surgeon's coat with a Union officer's uniform beneath, Urban searches his circa-1860s surgeon's toolbox for a different instrument. The Sykesville reenactor finds an antique trocar, a sharp-ended, tubular device with a removable inner sleeve. He shoves it through the soldier's soft belly flesh directly into the bladder, then pulls on the metal sleeve to siphon out red-tinted liquid.

The trocar overflows. People back off. Someone says, "Eww!"

Stick around, folks: He's going to remove a damaged eyeball next.

Not your standard setting for a finger-food party, agreed. But then this museum, rising up like a tabernacle of everything urologic at the back of an industrial park wasteland near Baltimore-Washington International Airport, is not your standard museum.

"He's [got it] again!" blurts out Rainer Engel, watching Urban prepare for another urological procedure on the anatomically correct dummy.

Engel's a doctor, and he runs the museum, so it's okay. In these hallowed halls, dropping the p-word is practically de rigueur.

A retired, German-born urologist whose prodding and probing is now done primarily at this museum (which he curates) and in the classrooms of the Johns Hopkins School of Medicine (where he teaches), Engel is in his early seventies and is a real character in a medical specialty where mannered eccentricities seem to be a prerequisite.

This evening he wears a deep coral-red sports jacket and black ribbon tie. He says he cut off the bushy gray muttonchops and shoulder-length ponytail that he had been cultivating for these Civil War reenactments: "My wife said it tickled her in bed!"

Guests gravitate to the lively and colorful Engel like sediment to a kidney. But Engel is quite serious when talking urology. Here's his lecture-like explanation of the discipline during the Civil War:

"They treated injuries to the bladder, penis and testes . . . mostly gunshot wounds or occasionally bayonet wounds. The most common urologic diseases were gonorrhea and syphilis."

In other words, all's fair in love and war?

"Yeah," says Engel.

In a world without antibiotics or knowledge of bacteria, with blood transfusions still 60 years off and amputation the cure du jour, Engel says medical diseases caused two-thirds of Civil War deaths. Treatments often contributed to fatalities. Physicians treated some 6 million illnesses during the war -- brought on by "malaria miasmas," "crowd poisonings" and "mephitic effluvia," which hovered around the privies.

A majority of troops suffered from typhoid, dysentery and diarrhea. "They treated venereal diseases with mercury, which actually helped," Engel says. But in high amounts, mercury is poisonous and destroys mucus membranes from the nose to the bowels, he says. Opium was the common drug doctors gave soldiers for intestinal problems.

"So many of the treatments invoked in those days were treatments where today we would say, 'My God, they did that?' On the other hand, by doing those things, they really pushed medicine forward. We eventually learned this was something good, this was something not good."

Every war does that, Engel says, happily mixing metaphors: "Urology got a kick in the butt from the Civil War."

Inside the exhibit are glass-encased displays of medical instruments from back in the day. Sets of long razor-sharp blades for amputations look like knives from a horror flick. Needle-like tools used to drain distended bladders are unnerving. Pliers used to chip off bone fragments give pause.

"Some of these things, I could use," acknowledges Aaron Sulman, a urologist and laparoscopy fellow at Johns Hopkins, examining the exhibit's antiquated instruments. Nowadays, he says, many procedures use fiber optics that allow urologists to see what they're doing. "But here everything appears to be by feel, or involve some sort of incision," he says. "Now there are better ways to accomplish these things."

Terry Chittick is especially attracted to the sepia photographs and excerpts from the wartime letters of Melvin John Hyde, surgeon of the 2nd Vermont Regiment. They provide the narrative of Civil War doctoring throughout the exhibit.

"I was in tears when I went in there," says Chittick, a retired nurse, now a florist in Middleburg, who is Hyde's great-great-granddaughter. In 1985, when she started tracking family genealogy after the death of an uncle and aunt, she discovered a shoe box full of 150 of Hyde's letters and compiled them in a 432-page book, "In the Field."

"It is drama," she says of Hyde's wartime experiences, which are highlighted by the exhibit: He was imprisoned. He saved wounded soldiers. He returned home unable to mend his broken family life. "That was the Civil War."

Another display shows the infamous Minie balls: During the Civil War, these soft-leaded bullets packed bone-shattering punch. They'd expand and explode and each fragment caused more damage inside the body.

"In those days, the biggest problem with a wound like that was gangrene, infection, and with the absence of antibiotics, you cut it off," says Engel, squiring a group of guests through the displays and providing commentary with Civil War fiddle music in the background. "Many soldiers thought it was better to live with three limbs than to die with four."

As the reception winds down, Engel grows reflective. "What are they going to say 100 years from now when they look at what we're doing?" he wonders.

Next year's exhibit is "Sex Perception and Performance."

We'll be awaiting our invite for that one.

Civil War Medicine, through July and August at the William P. Didusch Center for Urologic History. Monday-Friday, 9 a.m.-4 p.m., 1000 Corporate Blvd., Linthicum, Md. Call 410-689-3789 for information or visit www.urologichistory.museum.

Robert Urban, in the hat, and Rainer Engel demonstrate Civil War medical procedures on an anatomically correct dummy at the Didusch Center for Urologic History in Linthicum.Rainer Engel holds the mike as Robert Urban shows how a bullet was removed from the eye of a soldier. Below left, Engel, curator of the Center for Urologic History in Linthicum, leads grandson Andreas Kremer around the Civil War Medicine exhibit. Below right, a Civil War-era drug kit.A Civil War-era medical kit includes, among its many sharp, pointy, metal instruments, an amputation saw.