In March 1897 a Catholic priest stood in a Chicago hall in front of the city's officials, buttoned his coat over a vest half an inch thick, and told a marksman to fire a revolver into his chest. The bullet stopped. The vest was made of silk. Casimir Zeglen had come from Poland to a parish on the South Side, and in 1893 he had watched the city's mayor shot dead in his own house by a disappointed office-seeker. Assassination was the fashion of the age. Presidents, empresses and kings were being killed by pistol, and steel breastplates were too heavy to wear under a frock coat. Zeglen reasoned from something soldiers had noticed for centuries: a bullet that passed through a man was often found with a scrap of his silk handkerchief wrapped round it, unbroken. The fibre would not tear. So he layered it, tightly woven, dozens of sheets deep, with linen and a little wool, and when he had a vest he trusted he put it on himself. The demonstration worked, and he repeated it, and the Zeglen vest went into production. A Polish inventor refined the weave and the armour was offered to the crowned heads of Europe. Whether it would have stopped a rifle is another matter. It stopped the pistol rounds of its day, which were the rounds the assassins used. Silk is a protein, extruded by a caterpillar, and strand for strand it holds more tensile load than the steel the armourers had been bolting on. A worm had solved the problem of the flying bullet before any chemist had been born who could make a synthetic to match it, and the synthetic, when it came seventy years later, was engineered to behave like silk. The priest lived to be seventy-eight. Nobody ever shot him in anger.