Franklin H. Epstein, professor at Harvard Medical School and physician at Beth Israel Deaconess Medical Center, will be remembered as a researcher, confidant, mentor, and distinctly, as a singer.

“He was a perfect tenor, a beautiful voice,” said Katherine Hessler, a former student and researcher in Epstein’s lab.

Each year on July 14, Epstein would serenade his research lab with songs from the French Revolution. “He was always whistling, humming, or singing. He was a very musical guy.”

Epstein passed away last Wednesday. He was 84.

Epstein taught generations of medical students during his more than 30 years at Beth Israel. He was known to ask difficult questions during rounds, but was beloved by his colleagues and students.

“In every way Frank exemplified the ideal physician, investigator, teacher, and scholar. He was a superb scientist with an incisive ability to probe the essence of any research question,” Mark L. Zeidel, chair of the Department of Medicine at Beth Israel, wrote in an e-mail sent to hospital faculty. “Above all else, Frank was an inspiring teacher and mentor, who brought out the very best in everyone who had the privilege to learn with him.”

Epstein was the program director of the General Clinical Research Center at Beth Israel, where he studied mechanisms of acute renal failure. He also conducted research at Mount Desert Island Biological Laboratory in Maine, focusing most recently on the cellular transport of salt in a shark model of the ascending limb of mammalian kidneys. He worked in the Desert Island lab for 40 years and served as its president for 10 years.

As a research mentor in Maine, Epstein worked with high school and medical school students exploring marine physiology. Michael Amato, a freshman at the University of North Caroline, Chapel Hill, worked with Epstein last summer.

“He was patient with us and let us make mistakes,” Amato said. “He was always kind and patient.”

Amato recalled how Epstein made a point of connecting their research to the human body. “It really enhanced the experience, knowing you can help people in the future,” Amato said.

Epstein was able to bring “the bench to the bedside,” Hessler said, noting his strengths as both a physician and a scientist.

Epstein is perhaps best remembered for his personal warmth and kindness.

“He was an incredibly compassionate and generous human being,” Hessler said. “He really brought out the best intellectually. I learned from him about science, but he was also a very inspiring role model as a person as well.”