REVERSAL OF FORTUNE

On July 15, 1916, THE WEATHER in Paris was overcast and oppressively humid. Bleak light poured through the metal-framed windows of Louis Pasteur's former apartment upon gold-patterned wallpaper, oriental rugs, and carved antique furniture. The museum-like residence at the Pasteur Institute was filled with oil paintings, vases, statuettes, and other works of art Pasteur had received as gifts from grateful admirers. As Elie Metchnikoff lay in this shrine of science, pillows propping his large head with its mane of gray hair and beard, he held the hand of his wife Olga, fifty-seven, a slim, oval-faced blonde sitting at his bedside. He had devoted his entire life to science. Now science was letting him down.

Metchnikoff knew he was dying, but his worst fear was not death itself. What he dreaded most was that his passing away at seventy-one, decades too early by his own standards, would discredit his theories about life, health, and longevity.

He had been much better at creating new areas of research than at fitting into existing ones. The 1908 Nobel Prize in Physiology or Medicine had been his reward for helping found the modern science of immunity. He had then launched the first systematic study of aging, coining the term gerontology. In future generations, he argued, people could live to 150. To stay healthy, he believed they had to repopulate their intestines with beneficial microbes to replace harmful ones — for instance, by eating yogurt or other forms of sour milk.

Coming from such an acclaimed scientist, these ideas had created a sensation, making him an international celebrity and turning sour milk into a global mania. In a 1911 poll by a British magazine, he had been voted one of the ten greatest men in the world. But now that his heart was failing him less than halfway to his own target, his teachings threatened to die with him.

"Remember your promise — you'll perform my autopsy," he told an Italian physician who entered the room, one of his numerous trainees at the Pasteur Institute, where Metchnikoff had worked for nearly three decades. "And pay attention to my intestines, I think there's something there." Even after his death, he hoped to be doing what he had done all his life: serving as his own subject for research. When he made an abrupt movement, Olga pleaded with him to lie still. He didn't answer; his head had fallen back on the pillow.

The tricolor national flag on the Pasteur Institute's facade was lowered to half-mast, draped in black.

Millions of people were dying in a world war that had been raging for nearly two years, but this particular death was major news around the globe. The international press was unanimous in praising Metchnikoff, placing him beside Pasteur, Lord Lister, and Robert Koch among "the immortals in the lifesaving science of bacteriology." But just as he had feared, his death delivered a fatal blow to his theories of longevity.

Soon afterward, his name sank into oblivion. Hardly anyone followed up on his research, neither in aging nor in immunity. Only the yogurt craze he had launched on both sides of the Atlantic proved immortal. Indeed, outside the Pasteur Institute, to the extent that he was remembered at all after his death — except by historically minded immunologists and a handful of life-extension enthusiasts — it was usually in connection with yogurt.

There was one exception. In his homeland, Ilya Ilyich Metchnikoff was not just remembered but revered, and not at all because of yogurt.

When I was a girl growing up in Moscow in the early 1970s, Metchnikoff was known as the Russian Pasteur and upheld as a shining example of national talent. In company with Russia's other historic heroes, he was a cult figure, glorified by the Soviet regime as a way of instilling in the population a sense of belonging to a great nation. In my ninth-grade textbook, the ideologically weighted History of the USSR, he was canonized as "a model of selfless service to the Fatherland and to science." Like all the children in Moscow's Secondary School No. 732, to say nothing of the rest of the fifty million or so schoolchildren in the Soviet Union, I learned that Metchnikoff's valiant struggles against "bourgeois ethos" had helped pave the way for "Leninism, the highest achievement of Russian and world culture in the imperialist era."

But like many children of dissidents (my family had long-standing scores to settle with the repressive Soviet regime), I loathed this hero worship. In fact, I secretly suspected that Metchnikoff was a fake, together with most other Russian greats in my textbook, their accomplishments primarily products of communist propaganda. When I left Russia for good at seventeen, I would have been quite happy never to hear about any of them again.

Thirty years passed. While working as a science writer in Israel in the mid-2000s, I received an e-mail from Leslie Brent, a distinguished professor of immunology in the United Kingdom. In a search I had undertaken for little-known but key episodes in the history of science, I had asked him to list great immunologists whose life stories, in his opinion, had yet to be properly told. Metchnikoff's name, high on Professor Brent's list, jumped out at me. It brought back memories of my teenage self with my braids, fountain pens, and brown wool high school uniform. I was shocked by my own myopia. Had I wrongly dismissed a genius in my overall rejection of the party line?

To clear up this possible error of judgment that had been trailing me since childhood, I decided to investigate. Who was this man? Was he really as great as my textbooks had proclaimed him to be?

Delving into...