The discovery of vitamin B1 began with a search for microbes. In the late 1800s, microbes were the hot new idea in medical science: Louis Pasteur had recently linked disease to germs, and doctors were looking for microscopic explanations for all kinds of ailments. Even when those ailments had nothing to do with germs at all.

Take beriberi for example—a common disease that could cause nerve damage or heart failure. Beriberi had already been linked with diet, but when Dutch scientists started looking for its cause, they thought they might be looking for a microbe. To find that microbe, they tried infecting small animals (rabbits, monkeys, chickens) with the disease by exposing them to blood and urine from animals with beriberi.

When they did that, something strange happened. The rabbits and the monkeys never got sick. But the chickens, kept in coops at a research institute in Indonesia, did get sick. The problem was, they all got sick—not just the chickens that had been exposed to blood and urine, but the control groups, too. Christiaan Eijkman, who was running the experiment, bought more chickens and tried to infect some; he separated them from one another; they all got sick. Then, somehow, they got better.

The reason, he found, was their diet: When the chickens were fed on white rice alone, they came down with beriberi. When they were fed brown rice, they did not. No urine or blood required.

But even after further experiments had linked beriberi to a diet of white rice, and shown how consuming rice husks could prevent or cure it, scientists—including Eijkman—still believed the disease came from a pathogen or toxin, and that whatever was in the brown rice husks prevented it from taking hold. It wasn't until 1901 that Eijkman's successor, Gerrit Grijns, articulated clearly that it was the absence of some crucial substance, found in the husks of brown rice, that caused the disease. Eijkman didn't come around to that view until 1906.

A few years later, around 1910, an American Army captain in the Philippines started working on treating beriberi, and he brought in a chemist, Robert R. Williams, to help. The captain handed over a small bottle of of rice polish. Williams' task: Isolate and synthesize whatever it was in this stuff that was keeping beriberi at bay.

Williams wasn't the only scientists working on this problem: In 1911, a British scientist, Casimir Funk, crystallized a rice husk-derived substance that cured beri-beri. He called it a "vital-amine." In 1926, Dutch scientists in the same professional lineage as Eijkman and Grijns isolated the crucial factor, but managed to get its formula wrong. Throughout, Williams kept working on the task. At one point he "confiscated his wife's washing machine" to use as a centrifuge, the American Chemical Society reported.

With support from Merck—and more professional lab equipment—he finally managed to synthesize the substance—thiamine, or vitamin B1—in 1936. By this time, no one was looking for the microbe that caused beriberi anymore: Vitamins C and B2 had already been synthesized, and it was established that it was not exclusively the presence of unseen forces, like microbes, in the body but the lack of other tiny factors that could cause disease. Today, all kinds of foods are fortified with these vitamins, including Williams's B1. And beriberi is rare, but now treatable with a bit of thiamine.