I had a microbiology professor at university who liked to point out the role of serendipity in scientific discovery. The oft-cited example is Alexander Fleming's discovery of penicillin. The story goes that he left his lab in disarray on a weekend: petri dishes covered with bacteria were strewn about the lab bench, the window left open. When he returned the following week, dishes that once had bacterial growth were bare. He discovered that a fungus had blown through the window, contaminating his petri dishes, and killing the bacteria on them. Eventually, penicillin was isolated from the fungus.
Man of Culture from FiftyTwo magazine tells a similar story. Here's The Browser's capsule summary:
Story of a scientist and a life-saving compound. Rapamycin was first found in a soil sample from Easter Island. Over many years, it was proved that its immunosuppressant qualities were indeed revolutionary for organ transplants and cancer treatment. Discoveries are made by teams, but without this one man "tireless proselytising" the drug, it may never have been developed.
The bacteria that secretes rapamycin was found in the soil of one of the world's most remote islands. It made its way to Montreal and Surendra Sehgal's lab, where the secretion was found to have antifungal properties. That's luck. The story might have ended there without Sehgal's tenacity.
Sehgal devoted his life to this substance. Later studies revealed its immunomodulating properties and potential for use in organ transplants and cancer patients. When Sehgal's employer was sold to a US company and his work on rapamycin ordered to be destroyed, he made one last batch and stored it in his freezer at home with the helpful label "DO NOT EAT". Years later when management changed over, he eagerly petitioned his new bosses to restart his work on rapamycin. The bacterial culture he recovered from his freezer was still alive and well. From that point, it was a long slog to finally commercializing it as a drug. "Rapamune" was licensed by the FDA in 1999 to treat organ transplant patients; it prevents the body's immune system from rejecting the new organ. When Sehgal was diagnosed with stage 4 colon cancer in 1998, he was given six months to live. He put himself on a regular course of rapamycin and swore that he'd live at least another five years. He eventually passed away in 2003. In recent years, rapamycin has undergone further investigation as a cancer therapy and life-extension drug.
Serendipity is luck mixed with tenacity. You need to be at the right place at the right time, but you also need to be in the mindset that allows for discovery. For a scientist, that requires deep curiosity, creativity, and skepticism. I'm grateful for people like Sehgal. I hope that there are many more like him.