Just as dogs preceded humans in making the first risky voyages into space, a new generation of canines has now made an equally path-breaking trip -- from life to death and back again.

In a series of experiments, doctors at the Safar Center for Resuscitation Research at the University of Pittsburgh managed to plunge several dogs into a state of total, clinical death before bringing them back to the land of the living. The feat, the researchers say, points the way toward a time when human beings will make a similar trip, not as a matter of ghoulish curiosity but as a means of preserving life in the face of otherwise fatal injuries.

The method for making the trip is simple. The Safar Center team took the dogs, swiftly flushed their bodies of blood and replaced it with a relatively cool saline solution (approximately 45 to 50 degrees) laced with oxygen and glucose. The dogs quickly went into cardiac arrest, and with no demonstrable heartbeat or brain activity, clinically died.

There the dogs remained in what Patrick Kochanek, the director of the Safar Center, and his colleagues prefer to call a state of suspended animation. After three full hours, the team reversed their steps, withdrawing the saline solution, reintroducing the blood and thereby warming the dogs back to life. In a flourish worthy of Mary Shelley, they jump-started their patients' hearts with a gentle electric shock. While a small minority of the dogs suffered permanent damage, most did not, awakening in full command of their faculties.