CHICAGO — In the Middle Ages, your barber moonlighted as your surgeon and bloodletter. But anesthesia and the rise of hospitals led to a late 19th- and early 20th-century “surgical renaissance,” said Justin Barr, a Duke University medical history instructor. “These and other factors catalyzed the expansion of safer surgery that could treat effectively a broader array of conditions.”

The trade’s gruesome tools from centuries past are among the collection highlights in the International Museum of Surgical Science’s early 20th-century mansion on Chicago’s Lake Shore Drive. The 64-year-old museum was founded as a “hall of fame to surgery.” But with items such as a circa 1500 Austrian amputation saw and trephined Peruvian skulls from 4,000 years ago, upon which cranial surgery was performed, it’s aware of its yuck factor.

Student visitors are treated to an interactive “amputation demonstration” with replica Civil War-era surgical tools, and an after-hours “morbid curiosities” tour emphasizes surgical history’s darker moments, said Michelle Rinard, manager of education and events.

Works such as the museum’s 1970s copy of Rembrandt’s graphic painting “The Anatomy Lesson of Dr. Nicolaes Tulp” can be “really shocking for the extremely squeamish,” Rinard said. “We try and let them know in advance when they go through the museum that they might see something that’s not for the faint of heart.”

The museum largely addresses X-rays, pain and pain management, but the after-hours tour emphasizes “the kind of gross factor,” Rinard said. “It has more of an intention to gross people out or make them squeamish, which actually has a large following.”

Art therapist Katharine Houpt, who lectures on medicine and comics at the School of the Art Institute of Chicago, brings students to the inconspicuous museum. “As you walk up, you might be unsure if you’re in the right place,” she said. “Once inside, it feels like you are stepping into someone’s home — someone with an obsessive collection of surgical ephemera.”

In the library, Houpt says she thinks visitors can all but sense the mansion’s previous occupants, and she directs students to a first-floor apothecary, where “an animatronic pharmacist orients you to the healing elixirs and pep pills like a creepy Disneyland,” she said. “The foot X-ray machine is also not to be missed.”

Houpt’s students are shocked to hear that 19th-century Hungarian physician Ignaz Semmelweis was committed to an asylum after being ridiculed for suggesting that physicians wash their hands after surgery. “It was an outrageous idea at the time because ‘a gentleman’s hands are always clean,’ ” she said. “Stories like this give students a memorable narrative to attach to history, which allows them to use humor to reflect how related concepts show up in present-day discourse around health care.”

For squeamish visitors, Houpt recommends a tour, which peppers the morbid with humor. But those who are drawn to the gross factor aren’t part of a uniquely modern fad.

“Crowds watched gladiators kill each other in Rome; people came from miles around to witness public hangings for centuries,” Barr said. Graphic disease lists helped sell books in the 1600s, and the dissected-cadaver exhibit “Bodies,” whose website touts 15 million viewers, “remains financially successful for the sole reason that people are interested in the morbid,” he added.

“I think museums or other instances of public history can effectively utilize morbid stories or pathologies to engage an otherwise uninterested audience, as long as they put such material in context,” he said. “Gross for the sake of being gross is inappropriate. But leveraging people’s interest in dead bodies or dramatic stories to inform them about the history of surgery has utility.”

Spread over four floors, the museum is the brainchild of surgeon Max Thorek, who founded the International College of Surgeons in the 1930s. When the building adjacent to the college, at 1516 N. Lake Shore Dr., went up for sale in the 1950s, Thorek persuaded the college’s foundation to purchase it to create a surgical hall of fame. He donated his personal collection of letters and rare medical texts, and the museum commissioned art from the start.

The museum collection includes the first artistic commissions, including 12 stone statues in the Hall of Immortals depicting the men Thorek felt were medicine’s top luminaries. Works in the Hall of Murals portray those figures in action. Over time, representatives of the college’s outposts around the world donated artifacts, or often casts or reproductions, that were significant to their locations.

One world president of the college, who was Peruvian, persuaded his government to donate the skulls reflecting ancient surgeries and historical tools from about 2000 B.C. “Those are really significant and rare,” Rinard said. Unique among science museums, the collection combines historical artifacts such as the skulls, artwork and a medical text library, she added.

The museum’s longevity in the pricey neighborhood came into question last year, when the college sought in vain to unload its headquarters and the museum building for $22 million, Crain’s Chicago Business reported in October 2017. It has decided against trying again to sell the museum building. “I think that they realized that the museum in this location is too valuable to move,” Rinard said.

The museum — which collects admission fees (Tuesdays are free for Illinois residents), has members, rents spaces for private events and operates a gift shop — is updating exhibitions and hoping to keep growing its visitorship and team. From 2015 to 2016, it had more than a 50 percent growth in visitors, and it saw further increases in the past two years, according to Rinard. But it still has its work cut out for it.

“It’s pretty unknown, I would say, in Chicago,” she said.

The museum has an active presence on social media, and many visitors share photos on Instagram. Unlike at other museums, where wall labels may be undergoing a disappearing act, museum staff think that sometimes extensive didactics are important to help visitors understand a collection that includes obsolete and unfamiliar tools, Rinard said.

Photography is encouraged, although sensitive content can require cautionary signage. The museum encourages visitors to pause before sharing images of its exhibit on tattoos that David Allen creates for women who had mastectomies. It asks visitors to be respectful and remember that the subjects are actual people, Rinard said.

The museum also often works with Chicago Public Schools to bring students to the collections. “A lot of times, the museum is the only venue that they have to learn about medical history, because it’s not always taught in school,” Rinard said. “This is a good place for them to learn about the careers in medicine. Not only surgery, but nursing or medical illustration.”

International Museum of Surgical Science, 1524 N. Lake Shore Dr., Chicago.