Devin Katayama

This wasn't exactly what Metchnikoff had wanted. Throughout his career, he was always arguing over how the media took his research and ran with it or twisted his words. He gave caveats to his work. He called his ideas theories.

This wasn't exactly what Metchnikoff had wanted. Throughout his career, he was always arguing over how the media took his research and ran with it or twisted his words. He gave caveats to his work. He called his ideas theories.

This wasn't exactly what Metchnikoff had wanted. Throughout his career, he was always arguing over how the media took his research and ran with it or twisted his words. He gave caveats to his work. He called his ideas theories.

Metchnikoff was a scientist, but he was also a showman. Maybe yogurt wasn't a magic elixir, but science would still find the answers. Coming up, Metchnikov returns to Russia to face one of his biggest critics. He's 63 years old, and he doesn't know it yet. But he's running out of time.

Metchnikoff was a scientist, but he was also a showman. Maybe yogurt wasn't a magic elixir, but science would still find the answers. Coming up, Metchnikov returns to Russia to face one of his biggest critics. He's 63 years old, and he doesn't know it yet. But he's running out of time.

Metchnikoff was a scientist, but he was also a showman. Maybe yogurt wasn't a magic elixir, but science would still find the answers. Coming up, Metchnikov returns to Russia to face one of his biggest critics. He's 63 years old, and he doesn't know it yet. But he's running out of time.

On a cloudy May morning in 1909, Eli Mechnikov, bowtie and gray coat, and his wife Olga, white blouse, straw hat, descend from an overnight train.

On a cloudy May morning in 1909, Eli Mechnikov, bowtie and gray coat, and his wife Olga, white blouse, straw hat, descend from an overnight train.

On a cloudy May morning in 1909, Eli Mechnikov, bowtie and gray coat, and his wife Olga, white blouse, straw hat, descend from an overnight train.

Metchnikov has returned to Russia, where he was born, to visit the writer and philosopher Leo Tolstoy.

Metchnikov has returned to Russia, where he was born, to visit the writer and philosopher Leo Tolstoy.

Metchnikov has returned to Russia, where he was born, to visit the writer and philosopher Leo Tolstoy.

This wasn't just some random meeting. Although the two had never met, their work had been in conversation for years. Tolstoy was critical of Metchnikoff's work and threw shade on science in general.

This wasn't just some random meeting. Although the two had never met, their work had been in conversation for years. Tolstoy was critical of Metchnikoff's work and threw shade on science in general.

This wasn't just some random meeting. Although the two had never met, their work had been in conversation for years. Tolstoy was critical of Metchnikoff's work and threw shade on science in general.

And Metchnikov had written responses about Tolstoy, warning of the dangers of discarding science and embracing just spirituality.

And Metchnikov had written responses about Tolstoy, warning of the dangers of discarding science and embracing just spirituality.

And Metchnikov had written responses about Tolstoy, warning of the dangers of discarding science and embracing just spirituality.

Now it's time to talk face to face. Metchnikov had minds. Now he needed hearts. At Tolstoy's estate, Metchnikoff notes its simplicity. The furniture functional but old, any airs of luxury done away with. Tolstoy, 80, with a white flowing beard and white shirt, bounces down the stairs full of energy.

Now it's time to talk face to face. Metchnikov had minds. Now he needed hearts. At Tolstoy's estate, Metchnikoff notes its simplicity. The furniture functional but old, any airs of luxury done away with. Tolstoy, 80, with a white flowing beard and white shirt, bounces down the stairs full of energy.