Leonardo Da Vinci by Kathleen Krull Page A

“knowledge”—knowledge that explains the universe and the principles that make it work. Leonardo was very interested in scientia .
    Yet, in books about scientists, Leonardo isn’t always included. Perhaps that’s because, in the history of science, Leonardo is like a bridge. He stands right between the medieval view of the world and the modern view based on observation and experimentation. He looks backward to a time when nature seemed illogical, magical. He looks ahead to a time when nature is viewed as operating by rules and laws that can be discovered.
    Leonardo did indeed “see further” than anyone of his era. But whose “shoulders” did he stand on? And, in turn, did his work, his discoveries, inspire other scientists?

CHAPTER ONE
    “So Many Things Unknown!”
    EUROPE IN THE Middle Ages—first of all, there were no books. No printed books, that is. Just manuscripts in Latin, tediously copied by hand for the rich. Peasants had never seen one. Most people couldn’t read or write anyway.
    There were no bathrooms. Hardly anyone knew what soap or underwear was. The poor ate with their fingers; utensils were for the rich. Most adults had no more than a few teeth in their heads.
    Almost half of all children died before they were a year old. Women, on average, could expect to live only until age twenty-four. That’s because so many didn’t survive childbirth.
    In the countryside, the poorest peasants lived in extreme poverty and filth, ten to twenty people to a damp hut. They slept on the floor, their farm animals—as well as rats—beside them. After a bad harvest, when a famine would sweep through, people starved to death.
    In cities, streets served as toilets, and piles of excrement were left to mold until the next rain. Every few decades came a mysterious plague called the Black Death for the hideous black blisters it inflicted. The epidemic of 1348, which killed one out of every three people in Europe, was ascribed by many doctors to the rare placement in the sky of three planets.
    Doctors varied wildly in training, and progress in medicine was sluggish. There were physicians with degrees from famous universities. Still, the books they studied had been written more than a thousand years earlier. Other “doctors” had little or no schooling; barbers sometimes performed surgery. And if a limb had to be amputated, pouring boiling oil onto the wound was the method used to stop bleeding. A urine flask was the universal symbol for physicians; they spent more time examining urine than anything else.
    Doctors knew how to set broken bones. But the surefire cure for nosebleed? Pig manure.
    Ten green lizards, cooked slowly in olive oil, were believed to heal an open wound. One medicine was made from earthworms washed in wine and donkey’s urine; another called for a horn of a unicorn. Gout, a painful swelling of the joints, was treated by placing a sapphire ring on a certain finger of the patient. Blood-sucking leeches, applied when the planets were in alignment, could fix many ailments. More common was simply slicing open the skin, trying not to sever an artery, to allow the release of “bad” blood.
    People’s lives were short and violent. The rate of accidental death was high; the murder rate was twice as high. Many rulers were tyrants—some homicidal. Wars were common. No country, or even city, was stable. Women were viewed as vain—the devil’s decoy. And if they stood out in any suspicious way, they might be tried for witchcraft—and burned.
    The all-powerful Catholic Church was a beacon of light and learning in Europe in the Middle Ages. But non-believers were often brutally persecuted.
    In ancient Greece and Rome, in China, and in Arab countries, scientists had discovered much about astronomy, medicine, mathematics, and more. Islamic scholars translated the work of ancient Greek scientists into Arabic, keeping their discoveries alive, adding their own ideas to them. But in Europe, much of this body