It was not too long ago that the Mütter Museum was the very epitome of a Philadelphia secret, shut away in the dark quietude of the Northeast Corridor's attic.

People whispered about it, like they did about some dotty aunt, and sometimes even visited. Slices of Einstein's brain, cases of skulls, skeletons displaying the ravages of fibrodysplasia, Siamese twins, dwarfs, giants, curious growths — all manner of medical oddities graced its collection.

The Hyrtl Skull Collection at the Mütter Museum.
Evi Numen for the College of Physicians of Philadelphia
The Hyrtl Skull Collection at the Mütter Museum.

In the 1970s, attendance at the small museum, run by the College of Physicians of Philadelphia, hovered in the hundreds annually. But that began to change after the dynamic Gretchen Worden became curator and director in the 1980s.

When she died in 2004, more than 60,000 visitors were traipsing through the doors of the museum, located in the college's historic building on South 22nd Street.

Now the college has named current curator Anna Dhody the first recipient of the newly endowed Gretchen Worden Chair, the initial fruit of the first comprehensive capital campaign in the history of the organization and the Mütter, its most famous operating unit.

More dramatically for the public, the group plans to double the Mütter Museum's size, and rethink the use of the college's unusual medical library.

The Mütter would grow from its current cramped 5,000 square feet of floor space to a less-cramped 10,000 square feet. The library, which occupies an enormous chunk of the certified landmark building, would gain its first exhibition space. Its holdings include more than 400 books printed before 1500, along with tens of thousands of other books, periodicals, papers, and other documents.

So far, the campaign has raised more than $7 million, with $2 million of that going to the Worden Chair endowment. No total fund-raising goal has been set at this point. Officials said that the precise goal — and the exact scope of change — will be announced next June.

At the least, the college plans to raise enough to endow chairs for its head librarian, director of education, and head of public-health initiatives. There will also be a push to endow several programs, such as the college's active and growing history of vaccines program and website, its junior fellows education program, and other ongoing educational and museum initiatives. The timing of the museum expansion will depend on the pace of fund-raising.

A few skeletons and other bony artifacts — the Mütter calls them specimens — in storage at the museum.
Evi Numen for the College of Physicians of Philadelphia
A few skeletons and other bony artifacts — the Mütter calls them specimens — in storage at the museum.

The Mütter Museum expansion would be achieved within the building's current footprint by rethinking how the library and the museum intersect and by carving out space now taken up largely by library stacks.

The College of Physicians is not actually a college, but rather the oldest private medical society in the nation, founded in 1787 by two dozen doctors seeking to share knowledge and advance their science.

"What used to be considered almost exclusively, mostly, an old boys club for eminent physicians in the area has now become a site where, yes, physicians still form the undergirding fellowship, but we willingly, happily, share space with public programming for all ages," said Dr. Andrea Baldeck, chair of the college's board of trustees. Contributions from Baldeck, and Connie and Sankey Williams principally funded the Worden chair.

Baldeck said growth in museum attendance and burgeoning interest in medicine evidenced by the college's growing educational programs has spurred a "need for more efficient and versatile spaces."

The museum is bursting at the seams with visitors. About 180,000 visited last year — a number comparable to the physically much larger Cooper-Hewitt Museum and the Morgan Library, both in New York City.

Panoramic view of the upper level of exhibition space at the Mütter Museum.
Panoramic view of the upper level of exhibition space at the Mütter Museum.

"People come here to see the cabinet of curiosities," said Jon Goff, associate director of fellowship relations for the college. "We want to maintain the character of our building, but could we shift things around to make it easier for the public to be here on a Saturday when it's really, really busy and crowded? That's not great for the public and it's not great for our specimen preservation. It can get hot in there. Things can get jostled."

Richard P. Fitzgerald, the college's chief advancement officer, painted a picture of the Mütter these days as a kind of City Hall subway platform at rush hour.

"People are jostling and pushing to get close to the exhibitions, particularly our more well-known ones like the Hyrtl skulls," Fitzgerald said. "We need elbow room for our visitors."

On a recent day during the Made in America festival week, Mütter officials said 2,300 visitors came through the doors on a single day, a record number. Fitzgerald said the entire museum has a maximum capacity of 250 at any one time.

Given that demand, it is not unreasonable that the college would seek a little flexibility. Adding to the need is the fact that 90 percent of the 20,000-object collection is in storage and more than half the building is given over to the historical medical library and closed stacks.

What to do? The historic designation of the building makes outward expansion impractical and undesirable to the board of trustees.

There is also an awareness on the part of the board and management that growth can be perilous. Does a small institution, even one with a $30-$35 million endowment and a string of balanced budgets hovering at about $6.4 million, really need to expand? The city is littered with cultural institutions that followed the growth chimera into serious problems, if not disaster.

Then there is the character of the Mütter museum — so distinctly 19th century with its grand staircase, its wooden exhibition cases, its cramped and antiquated display aesthetic. Will a renovation and expansion scrub the character out of the interior?

The lower level of the Mütter Museum with some osteological (skeletal) specimens on display for the public.
Evi Numen for the College of Physicians of Philadelphia
The lower level of the Mütter Museum with some osteological (skeletal) specimens on display for the public.

Dhody said museum and college officials are very aware of the feel of the museum.

"We understand that people absolutely respond to the aesthetic," she said, adding that any changes will in part be driven by a desire to "retain the 19th century feeling." They are working with the Philadelphia architectural firm KieranTimberlake.

"We do not have an interest in creating stark white minimalist galleries," said Baldeck, chair of the board. "This is all about maintaining the architectural integrity and details of the place. The new places that will be created out of the stacks will be thoughtfully of a piece with what currently exists; none of the interior here is slated for removal."

Said Fitzgerald: "The ideal for me is the day we open, somebody comes up to me and says, 'This feels like its been here a hundred years.' "

Changes to interior will come only after the staff and programs are on an even keel, financially. "If the funding is mostly for endowing the chairs, OK, that's where it will go," said Baldeck. "The building won't be changing so quickly, but we will be making constant progress."