Image: Edmund L. Andrews

WONDERMENT was felt by many visitors to "Human Body Worlds" in Mannheim, Germany, 1997, where they saw human corpses made plastic.

Ten real human corpses are slated to travel the U.S. this summer--not for any sort of reburial or medical school exchange program, but to be put on display at science museums. Roy Glover of the University of Michigan and Dan Corcoran, president of Corcoran Laboratories, who are preparing this "anatomical road show," hope it will serve to educate, not shock, the general public. But it is hard to know what the reaction will be: A similar exhibit that opened in Mannheim, Germany, in 1997, called Human Body Worlds, elicited fierce public debates over the educational value of displaying real corpses versus the dignity of the dead.

By comparison, Glover and Corcoran's exhibit "will be less spectacular" than the German show, Corcoran notes. Each dissected body will reveal a different tissue or organ system. And organs in normal and pathological states will illustrate disease processes. One exhibit, for example, places the lungs from a healthy individual, a lung cancer patient and a patient suffering from asbestosis side by side for comparison. The sight packs a powerful lesson. But the fact that these organs are from real corpses may still spark a firestorm of controvery just the same.

What makes this sort of show possible is a technique called plastination, which preserves bodily tissues by replacing all the water and fat in them with a polymer. In other words, this method produces real plastic bodies. For this reason, it has many advantages over conventional preservation: the bodies remain very life-like, and they are non-toxic, odorless, dry and very durable as well.

Image: Roy Glover, University of Michigan

SECTION of a plastinated human head shows the blood vessels clearly.

Gunther von Hagens of the University of Heidelberg, Germany, creator of the Mannheim show, invented the process in 1978. It has four basic steps: anatomists must first fix the material by, for example, immersing it in a formaldehyde solution--similar to conventional fixation techniques. Colored substances can be injected into blood vessels to highlight them at this stage. Hollow organs, such as the heart, must be dilated during fixation. To prepare thin sections, fresh or fixed bodies are deep-frozen to temperatures near -70 degrees Celsius and cut into 2.5 millimeter slices with a band saw.

Second, preparators need to remove all water and fat from the specimen. This dehydration is achieved by placing the material into a solvent, usually acetone, and cooling it down to -15 to -25 degrees Celsius, a process called freeze-substitution that minimizes shrinkage. Over time, the solvent replaces all the tissue water and most of the fat.

During the third step, called "forced impregnation," the specimen is placed into a liquid polymer, mixed with a slow-acting crosslinker that catalyzes the polymerization reaction, and placed under vacuum. This procedure is performed either at sub-freezing or room temperature, depending on the polymer and crosslinker used. The vacuum makes the more volatile acetone evaporate, allowing the polymer to replace it. Bubbles form at the surface of the mixture, and together with the vacuum, they indicate how far the process has advanced. At this point, slices are clamped between two glass plates and cast by adding polymer.

Image: M.-C. Sora, University of Vienna

PLASTINATED LUNG clearly reveals the damage done by years of smoking.

After adjusting the final position of the body, the polymer is hardened (or cured) in the fourth step by exposing it to a gaseous catalyst or to UV-light and/or heat, depending on its properties. The glass plates are then dismantled from sections.

Overall, the kind of polymer used determines the optical and mechanical nature of the results. Silicone is best suited for preparing whole bodies and organs--and for thick sections, which consequently remain fairly flexible and naturally looking. Epoxy resins produce very firm products and so are used for thin, transparent body or organ slices. Polyester is the polymer of choice for brain slices because it preserves the visual distinction between gray and white matter.

The value of using plastinated bodies and organs in the classroom is hard to dispute. Not only are they used in anatomical courses at medical schools, but also in high school biology classes: Glover's laboratory, for example, has prepared several frogs and rats for two high schools in Michigan. And because these specimens can be used almost indefinitely, they help reduce the number of animals killed for dissections each year.

What is debatable, some people maintain, is the use of plastinated bodies as a form of art. The German exhibition both fascinated and horrified (one man in front of me at the show fainted, and he was not the only one who had a strange feeling in his stomach). Still, long lines steadily formed in front of the museum, which eventually decided to remain open around the clock to cope with the masses. Some 800,000 visitors were counted in total in Mannheim, and similarly high numbers viewed the exhibition when it traveled to Japan, Vienna and Cologne, where it currently resides.

Image: Edmund L. Andrews

RUNNING AWAY from the German exhibition: Some visitors found "the runner" with his muscles dissected offensive.

The show includes some 200 plastinated bodies or body parts. Visitors can follow the makeup of a human body by looking at a series of thin longitudinal (see side bar) or cross sections. Several bodies are opened up or taken apart in layers, showing the relative positions of bones and organs. In one preparation, all the nerves are colored yellow, making it easier to follow them through the body in three dimensions. In another, the abdomen of a pregnant woman, lying on her side, has been opened, giving access to the fetus in her womb. A series of embryos from different stages of pregnancy--some with abnormalities--sit on black velvet in a glass case, illustrating the complexity of human development.

One plastinated man is carrying his own skin over his arm like a coat, exposing his skeleton and muscles. Other exhibits, also stripped of their skin, are posed as a runner, a fencer and a chess player, revealing their muscles in action. These bodies give the strange impression of being alive, which is one reason why they remain so controversial.

The German show indeed comes close to crossing the border between science education and exhibition, with dead humans becoming mere objects "re-created" by an artistic anatomist. Corcoran and Glover plan something more tame. "The bodies will be erect and supported," Glover says, "but they will not be posing in any way." Using real bodies, he asserts, is far superior to assembling artificial models: "There is never a good copy. Each body is unique, different and fascinating. By looking at them, we want our visitors to better understand their own bodies."

At the moment, the organizers are still negotiating venues and dates with museums and institutions all over the country. The plan is to have the exhibit, which could be up and running as early as June, traveling for several years, spending five to six months at each venue. Of course, that plan may be altered depending on the public's reaction. Will the display of "real plastic bodies" meet a similar mix of enthusiam and repulsion in the U.S. as it did in Germany?