During their second-year show three years ago, the Class of 2001 sang (to the tune of “Jesus Christ Superstar”), “We’ll all take a fifth year before we’re done.” Meant as a joke, the lyric was almost prophetic. Many in the class did stay for a fifth year. Meanwhile, the number of students in the Class of 2002 who took a fifth year was lower than average. These two anomalies swelled the ranks of this year’s graduating class to 112, the largest in recent memory.

The students’ choice of Commencement speaker was also a departure from the norm. Paul E. Farmer, M.D., Ph.D., has followed an unusual path since he received a medical degree and a doctorate in anthropology from Harvard in 1990. He works in Haiti’s central plateau, tending to the rural poor in the poorest country in the Western Hemisphere. He also travels the world, defying the experts as he finds ways to bring medical care to tuberculosis patients in Peruvian slums or Russian prisons.

“When we began to treat AIDS patients in rural Haiti, it was dismissed as neither cost-effective nor sustainable,” Farmer said. “In fact, some experts argued that it was downright irresponsible to use antiretroviral drugs in a setting of such squalor. I underline the word experts here because such critiques have never, in my experience, come from poor patients and their families. I have never had someone say, ‘You know, doc, I’m very interested in treatment, but being a Haitian I’m really not cost-effective.’ ”

In closing, Farmer urged the new doctors to use their skills to change the face of medicine.

“Try not to constrict your borders to the confines of a single hospital,” he said. “The rest of the world is out there. This world will find you, even if you are hidden away in a hospital or a lab. It is my hunch and my hope that you will succeed in the challenge now before medicine, now before doctors-to rebuild modern medicine on a foundation of evidence and equity.”

Dean David A. Kessler, M.D., awarded Farmer the Peter Parker Medal for his contributions to medicine. “You demonstrate that there is all the difference in the world between a profession and a calling,” Kessler said. “Dr. Farmer, you teach us what it means to have a calling.”