When people in Baltimore talk about ghosts, they usually think of places like Green Mount Cemetery, or the Admiral Fell Inn in Fells Point. But one of Baltimore’s most apparently active ghosts resides in the century-old building of the Maryland State Medical Society, also known as MedChi.MedChi is celebrating its 225th anniversary, being founded in 1799. As you might imagine, the building is filled with uncountable old things. From books dating back to 1567, portraits painted in the late 1700s, creepy medical instruments, and of course, the resident ghost, the building is a look at medicine through time.Marcia Crocker Noyes was the librarian at MedChi from 1896 until her death in 1946. She was required to live in the building (in a penthouse, no less!), because she needed to be available to the doctors at all hours. The original Google, you might say.Although Marcia is buried at Green Mount Cemetery, she’s still active throughout MedChi’s 1909 building in Mt. Vernon. She moves things, finds old paintings, and walks through the hallways, still looking after the building she helped to design.MedChi invites guests to come tour the building and hear about MedChi’s history, Marcia’s incredible life, and the ghost stories that have continued ever since her death. Guests will also have a chance to visit the MedChi Museum of Maryland Medical History and see some of the collection’s creepiest books.Tours will be held on Monday, Oct. 28; Wednesday, Oct. 30; and Thursday, Oct. 31, from 6:30 to 8 p.m. Tickets are $10 per person and are available HERE. Funds raised will support the MedChi Archives. After you pay for your tickets, visitors are asked to indicate which date you’d like to attend. If you select Halloween, MedChi encourages you to dress up!Last year, tickets sold out in a few hours, so if you’re interested, act fast!