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How Vaccines Train Your Body
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How Bees Make Honey
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The Goldsmith Who Printed the Bible
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Grab your coffee and let’s dive in.

The first vaccine was tested on a gardener's son. On May 14, 1796, Edward Jenner, a country doctor in Berkeley, Gloucestershire, made two shallow cuts in the arm of eight-year-old James Phipps and rubbed in pus from a cowpox sore on a milkmaid's hand. It sounds reckless, and by modern standards it was. But Jenner was up against smallpox, which was killing an estimated 400,000 Europeans a year and blinding about a third of those who survived. The best protection on offer was variolation. A doctor would deliberately infect a healthy person with a small dose of smallpox itself and hope for a mild case rather than a fatal one. Dairy country had a gentler theory. Folklore held that anyone who caught cowpox, a mild disease of cattle, would never catch smallpox. Jenner decided to test the folklore on a child.

The real test came on July 1. Jenner infected Phipps with matter from a fresh smallpox sore, and nothing happened. Several months later he tried again, and again the boy stayed well. The Royal Society declined to publish his paper, so in 1798 Jenner printed it himself. He called cowpox variolae vaccinae, “smallpox of the cow,” from vacca, the Latin for cow. In 1800 his friend Richard Dunning coined the word vaccination. What Jenner could not explain was why it worked. The answer lies in white blood cells that learn from experience. When a new germ gets in, B cells produce antibodies, Y-shaped proteins that latch onto the invader and mark it for destruction. T cells kill infected cells and direct the wider attack. That first response takes a week or two to build, which is why a first infection can be so dangerous. Once it is over, a reserve of memory B and T cells stays behind, ready to move far faster if the same germ ever returns. Cowpox and smallpox are close enough relatives that the memory of one covers the other. A vaccine simply stages that first meeting with a harmless stand-in.

Jenner was not quite the first to try it. In 1774, twenty-two years before Phipps, a Dorset farmer named Benjamin Jesty gave his wife and two sons cowpox during an outbreak, but he never published a word about it. Jenner stayed close to his young volunteer. He later gave Phipps a rent-free cottage in Berkeley, and Phipps, by then a grown man, attended his funeral in 1823. The campaign that began with that one small arm ended on May 8, 1980, when the World Health Assembly declared smallpox eradicated. In the twentieth century alone, the disease had killed an estimated 300 million people. The protection a vaccine leaves behind can last for most of a lifetime. In 2003, researchers at Oregon Health and Science University found that more than 90 percent of volunteers vaccinated up to 75 years earlier still carried substantial immunity. The cow in the name may even be the wrong animal. In 2017, scientists sequenced an American smallpox vaccine made in 1902 and found that its core genes were 99.7 percent identical to horsepox.

Every spoonful of honey starts out as something that would spoil within days. Flowers make nectar, a sugary liquid, to bribe pollinators, and it is mostly water. Left as it is, it would soon ferment. The bee that collects it is already near the end of her working life. A worker usually spends her first weeks as an adult indoors, cleaning cells and feeding larvae, and only then moves on to foraging, the last job she will ever do. Out among the flowers, she drinks nectar through her strawlike tongue into a storage sac called the crop, or honey stomach. It is separate from the stomach she uses to digest her own food. Filling it can take anywhere from 50 to 100 flowers. Multiply that across a colony and the numbers turn absurd. To make a single pound of honey, the foragers fly roughly 55,000 miles, more than twice around the Earth.

The transformation begins before she gets home. Glands in her head add an enzyme called invertase, which splits table sugar into two simpler sugars, glucose and fructose. A second enzyme, glucose oxidase, turns a little of that glucose into gluconic acid and hydrogen peroxide. Together they make the honey acidic and hostile to bacteria and mold, and very little can grow in the finished product. At the hive, the forager passes her load mouth to mouth to a younger receiver bee. The receiver pushes a droplet out onto her mouthparts again and again, drawing it back in each time so some of the water can evaporate. Then she spreads it thinly in a wax cell, and the fanning begins. Rows of workers beat their wings to drive air across the comb and carry the moisture out of the hive. When the water content falls to about 17 or 18 percent, the honey is ripe. The bees seal each cell with a cap of beeswax, which they secrete as small flakes from glands on the underside of the abdomen.

All that work is a pantry for winter. During a good nectar flow, a strong colony can store up to two pounds of honey in a single day. It will need every bit. Even a small colony may need 35 pounds or more to last until spring, depending on the climate. Through the cold months the bees huddle in a tight cluster and shiver their flight muscles for warmth, burning honey as fuel. Beekeepers take only the surplus the colony can spare. Spread across the whole workforce, each bee's share is tiny. The figure most often quoted is about one-twelfth of a teaspoon in a lifetime, although estimates vary with the season and the method. By that arithmetic, a one-pound jar holds the life's work of roughly 770 bees. A summer worker usually lives only a few weeks. Most of the honey she helps to make will be eaten in winter by bees that have not yet emerged from their cells when she dies.