How to Preserve Human Specimens | Conservation Lab

We talked to the guy who's responsible for rehydrating dried-up fetuses, fixing wonky skeletons, and cleaning skulls at the Mütter Museum.

In art institutions across the globe, time machines and investigation rooms exist behind closed doors. Dusty artworks go in and come out looking centuries younger; artists’ secrets are brought to light; and hidden, unfinished images emerge from behind famous compositions. Every week, we'll peek beneath the microscope and zoom in on the art of preservation, where art meets science and just a little bit of magic: this is Conservation Lab.

Down in the basement of the Mütter Museum in Philadelphia, known worldwide as a treasure trove of medical history, there's a "bone room,” with racks upon racks of human remains: a wet lab full of brains, hearts, and fetuses floating in glass jars, and a conservation lab filled with tools that help keep this unusual collection intact for generations to come. It’s also where you’ll find George Grigonis, Collections Technician and Conservator, and the lab’s head problem-solver for the past six years—originally as a volunteer, then as part of the staff, despite being “technically retired.” Grigonis is a fount of information, and is eager to pass on his tremendous knowledge to younger generations—be it Mütter staff, the many interns and students that pass through, and, for the duration of our brief visit, The Creators Project.

A skull from the Hyrtl Collection.

To better display the 139 human skulls that make up the collection of Joseph Hyrtl, a 19th century Austrian anatomist who used them to debunk phrenology, Grigonis designed new mounts to replace the old ones made of brass and wood. As the conservator demonstrates for us with a skull that once defined the facial features of a Greek sailor, the patented foam board mount provides stable support, correcting prior vibration issues that had resulted in the loss of teeth and other damage throughout the years. “We found a bunch of teeth in plastic bags, in a paper file that just read ‘Hyrtl Skulls.’ So for each tooth, we had to identify the skull and the socket, and make sure it fit. We had a little bit of a jigsaw puzzle to solve,” the conservator recalls. In addition to getting their teeth back, the skulls all got a good cleaning. That process, as it turns out, is dead simple: soap, water, and lots of elbow grease.

Old skull mounts, above, and the new mount designed by Grigonis, below.

Skulls are such a common motif that it’s easy to forget that you’re looking at the real thing. A quick comparison with a 3D printed replica, however—which Grigonis pulls out as an example of what the Mütter can send over for exhibitions at other museums—will reorient your perceptions in an instant. It’s the same feeling around the skeletons that balance on metal hooks in the bone room. From a distance, they could just as well be hanging in the corner of a high school science classroom, but as you get closer, you suddenly appreciate all of the unique details that make it completely and unnervingly real, including the metal hardware drilled into the bones in order to hold them together.

Tovah Ross-Mitchell and George Grigonis rearticulating a skeleton. Courtesy of the Mütter Museum

Grigonis has repaired and replaced much of that hardware, and trained others to do the same. For one skeleton that he was asked to prepare for an outside institution, he had to go off-campus: “My wife wouldn’t let me bring the skeleton home; I had to do all of it in my friend’s garage,” he says, laughing.

Back in the museum’s galleries, in front of a display holding skeletons prepared in the early 1800s, Grigonis explains that, whenever possible, the articulations were maintained by leaving the cartilage and the connective tissue in the joint areas, and letting it dry. Over time, though, the tissues and bones can shift and require adjustments. “If we need to reposition some of these, it’s a simple matter of rehydrating the connective tissue,” Grigonis explains. “We rehydrate it, and then we can reshape it and reposition it—and then let it air dry.”

A dried-up stomach, displaying adenocarcinoma, that will need to undergo rehydration

Rehydration works wonders in other areas as well: As Grigonis pulls out two human stomachs in glass jars onto a table in the lab, he points to the stark differences between the two. One looks like normal tissue floating in liquid preservatives; the other, a specimen displaying a cancerous tumor, is entirely dried up—which can happen when the jar leaks, or when the seal fails, leaving the liquid to evaporate. “That’s what the first one used to look like,” points out Grigonis, before launching into a detailed explanation of the rehydration process, which involves temperature-controlled baths, vacuum chambers, and ethanol solutions. Sparing the details, the main takeaway is the following: Rather than giving up on these shriveled up specimens and throwing them out—as many institutions do—the Mütter has found a way to save them.

A stomach, before and after rehydration

Nearby, there are more curiosities lying around: a tray of foreign objects removed from patients’ airways by laryngologist Chevalier Jackson, remounted with archival materials and reframed by Grigonis in his home wood shop; a wax model of a surgical procedure, which was once in pieces and put back together by the conservator (“The process is a little bit like welding,” he notes); and a plastic reproduction of a Chinese woman’s bound foot, recreated so that the one on permanent display in the museum wouldn’t need to travel.

The work of a conservator at a medical history museum, then, seems to require polymathic abilities—and tireless energy. “There’s ten to twelve lifetimes of work here,” concludes Grigonis.

Replica of a bound foot, with modeling materials at left

Tray of foreign objects retrieved in patients’ airways by Chevalier Jackson

More specimens in the wet lab

Skeletons in the bone room

To learn more about the Mütter Museum, click here.


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