Today, we survive the Black Death. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

The plague Yersinias Pestis swept out of Asia in 1347. An over-populated Europe had been damaged by 50 years of famine. Now rats carried this disease off ships in Genoa. In just four years it killed off 40 percent of the people in Europe. It took three forms: "bubonic" plague hit the lymph system, "pneumonic" plague attacked the lungs, and "septicemic" plague assaulted the blood. But the words "Black Death" encompassed it all.

After 1351, the Black Death went from the epidemic phase, where the disease suddenly appears, to the pandemic phase. During the so-called "plague pandemic," the plague settled into the local environment and kept coming back every few years to whittle away at the population. From the first famines in 1290 until the plague pandemic began to recede in 1430, Europe lost three-quarters of its people. The Black Death is far and away the greatest calamity our species ever suffered.

And what, do you suppose, was left in its wake? Well, it unraveled the tapestry of the feudal system. It left many survivors wealthy. Manual labor became precious. Wages skyrocketed, and work took on a manic quality. When death rides on your back, time also becomes precious. Minutes seem to count for something. The Church-centered world before the plague had been oddly timeless. Now people worked long hours, chasing capital gain, in a life that could end at any moment. The first new technology of the plague years was time-keeping -- mechanical clocks and hourglasses.

Medicine had been a function of the Church before the plague. Physicians were well-paid, highly-respected scholars. They spun dialectic arguments far away from unwholesome sick people -- not unlike some of today's specialists. 13th-century medicine, like the 13th-century Church, had failed miserably in coping with the plague. Both medical and religious practice now shifted toward the laity. Medicine was redirected into experimentation and practical pharmacology. Medical books were now being written -- not in Latin -- but in the vernacular, and by a whole new breed of people.

Technology had to become less labor-intensive. It had to become high-tech. For good or evil, the plague years gave us crossbows, new medical ideas, guns, clocks, eyeglasses, and a new craving for general knowledge. And so the rainbow at the end of this terrible storm yielded its pot of gold. The last new technology of this ghastly 150 years was the printing press. It finally melted what Shakespeare had named the winter of our discontent. It provided access to knowledge. And it started the rebirth of Europe.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

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Gottfried, R.S., The Black Death: Natural and Human Disaster in Medieval Europe. New York: The Free Press, 1983.

McNeill, W. H., Plagues and Peoples. New York: Anchor Book, 1976.