The Ten Most Beautiful Experiments by George Johnson (Alfred A. Knopf, $22)
William Harvey sliced open a live snake and, while pinching its vena cava, or main vein, watched as the heart into which it pumped blood grew paler and smaller. He then pinched the reptile’s main artery and saw how obstructing the flow caused the heart to bulge. In this way the 17th-century London physician proved that blood circulated—a radical idea that overturned the assertion of Galen, the second-century physician, that “invisible pneuma” enlivened the body’s fluids. This is just one of the 10 “beautiful experiments” that science journalist George Johnson explores; others include A. A. Michelson’s clever measurement of the speed of light, Ivan Pavlov’s observations of dogs drooling in anticipation of food, and (my favorite) Isaac Newton’s insertion of a probe behind his eyeball to observe the effect on color perception. Only one drawback mars Johnson’s account: Great experiments conducted by women scientists—including Barbara McClintock’s discovery of jumping genes—are all but ignored, appearing only in a brief note at the end of this otherwise absorbing book.