S. Allen Counter, a Harvard neurobiologist and explorer who reclaimed the reputation of Matthew A. Henson, a black explorer on Robert E. Peary’s 1909 expedition to the North Pole, and tracked down his descendants in Greenland, died on Wednesday at his home in Cambridge, Mass. He was 73.

The cause was cancer, his daughter Philippa Counter said.

Dr. Counter, a member of the Explorers Club, combined a scientific career with travel to the four corners of the earth. At Harvard Medical School, which he joined in 1970, his research on nerves and muscle synapses led him to such far-flung destinations as Ecuador, to study the neural damage caused by lead-glazing in the village of La Victoria, and China, to study acupuncture.

One of his interests — discovering the cause of widespread hearing loss among the Inuit of Greenland — dovetailed with a historical mystery he hoped to solve. While dining with Swedish colleagues in the late 1970s, he was told that both Peary and Henson, Peary’s main assistant on all but one of his Arctic expeditions, had left descendants in northern Greenland, the product of their relationships with Eskimo women.

Dr. Counter, who had been fascinated by Henson since childhood and had written extensively on the contributions of black Americans in remote places, made it his mission to track down their sons and descendants.