Microbes Show Exquisite Taste in Art

June 6, 2005 — -- More than a century ago, the French artist, Edgar Degas, crafted intricate sculptures from beeswax, lard, clay, and odds and ends such as cork, wood, wire, and rags. Now scientists have found that colonies of bacteria and fungi appear to be feasting on the work.

"They noticed that the statues were 'sweating,'" said Kristen Bearce, a microbiologist at Harvard University who has been testing the sculptures' surfaces for microbial life. "The sweating is likely the freeing of lipase as the bacteria eat the sculptures."

The sculptures, depicting intimate scenes of women bathing and models of horses and dancers in action, are featured at the National Gallery of Art in Washington, D.C. Among them is the famous, nearly life-sized "Little Dancer Aged Fourteen," which has since been used for bronze castings (something the artist never sanctioned during his lifetime). No samples were taken, however, from this particular work.

Before their purchase by Paul Mellon and subsequent donation to the gallery, most of the sculptures had been stored in a foundry basement in Paris where they had long been exposed to sullied air. Bearce says the bacteria found so far on the sculptures are common in soil and dust.

Today the works are kept in climate-controlled, Plexiglas display containers which, conservators worry, may be offering a cozy home for the microbes. Ralph Mitchell, an applied biologist at Harvard University and lead supervisor of the study, added, that despite identifying microorganisms from the wax sculptures, the works are being "well maintained" by the museum and "are not in any danger of degradation."

Testing for microbes on the art is the museum scientists' first step to ensure the works are adequately protected from this point forward.

"Clearly the microbes are not doing too much damage because the objects have been around since 1880," said Barbara Berrie, a conservation scientist at the National Gallery of Art. "But now we're concerned that they're in a stable, quiet environment and some of the bacteria and fungi will find it a nice place to grow."

To test for microbial infection, Bearce and Mitchell swabbed the statues and then cultured the samples. They found over half of the bacteria cultured from the swabs produced enzymes that could break down wax, almost 60 percent produced enzymes that can digest starch, and some 24 percent had the ability to digest both starch and wax.

"Some sculptures had more microbes than others," Bearce said. "We think it had to do with their composition."

Meanwhile, Berrie said that previous tests on the sculptures have shown that resins in the works may be releasing gas vapors and most likely contributing to part of the "sweating" seen in the sculptures.

"Some of them get glossy with moisture," said Berrie. "This has been noted in many wax sculptures -- the Louvre has also noticed this with some of their works. It's due to 19th century modeling mixtures which contain fats and beeswax."

There is some question over how much Degas, himself, might have minded that time is taking a toll on the statues. Some records suggest he never intended to display the works, which were found in poor condition in his studio after his death in 1917.

Some have suggested that Degas worked in sculpture mainly as a practice to refine his painting. Other records suggest the artist may have focused more on sculpture later in his life only because his failing vision forced him to resort to the more tactile medium.

In 1921, journalist Francois Thiebault-Sisson recorded that the artist had once said, "I modeled animals and people in wax for my own satisfaction, not to take a rest from painting or drawing, but to give more expression, more spirit and more life to my painting and drawings."

But Suzanne Glover Lindsay, an art historian at the University of Pennsylvania who is collaborating with National Gallery conservators on a book about the artist's statues, says other records suggest Degas did, in fact, consider the statues finished works fit for display. She adds that the work, itself, suggests it was meant for more than practice.

"The surfaces are very carefully worked and tooled," she said. "The problem with Degas' quotes is for every statement he seems to give someone else a statement to the opposite effect. You have to be careful about interpreting them."

There is even confusion over which of the works were displayed during his lifetime. Previously, art historians believed only the statue of the 14-year-old dancer was shown during Degas' lifetime. But recovered flyers from the late 1800s suggest that some of the other wax sculptures were shown in salons in Paris at the time.

One thing is certain, however: Degas avoided working with permanent media such as bronze. In fact, he may not have approved of the bronze castings taken of several of his wax sculptures after his death. Instead, he preferred art forms that he could always tinker with later -- such as wax, paint and pastels.

Wax sculpture may have been a more pliable medium for the artist, but today its preservation presents a much trickier challenge than the bronze castings. To try and keep microbes from further munching away at the works, Berrie says she and her colleagues are considering adding purified air circulation systems to the sculptures' display cases.

"We realize the fatty acids in the works can be a food source for bacteria," she said. "But a proper air exchange system can inhibit happy conditions for the microbes."