1. It is below 0°F outside, but the dedicated runner bundles up and hits the roads anyway. “You’re crazy,” shouts a neighbor. “Your lungs will freeze.” Why is the well-meaning neighbor wrong?

2. Why does breathing through the mouth instead of the nose dry the throat out?

3. What color might the insides of prehistoric human lungs have been? Why?

4. On December 13, 1799, George Washington spent the day walking on his estate in freezing rain. The next day, he had trouble breathing and swallowing. Several doctors were called in. One suggested a tracheotomy, or cutting a hole in the president’s throat so he could breathe. He was voted down. The other physicians suggested bleeding the patient, plastering his throat with bran and honey, and placing beetles on his legs to produce blisters. Within a few hours, Washington’s voice became muffled, his breathing more labored, and he grew restless. For a short time, he seemed euphoric; then he died. Washington had epiglottis, a swelling of the epiglottis to 10 times its normal size. How does this diagnosis explain Washington’s symptoms? Which suggested treatment might have worked?

5. Why can’t you commit suicide by holding your breath?

6. Why do you think the times of endurance events at the 1968 Olympics, held in 7,218-foot-high (2,200-meter-) Mexico City, were rather slow?

7. Why might it be dangerous for a heavy smoker to use a cough suppressant?

8. The most successful treatment for lung cancer is surgery performed when a tumor is small and confined to one lung. The entire lung or the lobe containing the tumor may be removed. Many physicians, however, will not attempt such surgery on a patient who is a heavy smoker because of a second illness. What might this illness be?