BOOK REVIEW : One Scientist Under the Microscope : THE THREAT AND THE GLORY Reflections on Science and Scientists<i> by P.D. Medawar</i> Harper & Row $22.50, 277 pages

I wish I had known Peter Medawar, the British Nobelist who received the prize for physiology or medicine in 1960. Those who did, speak of him with awe.

By all accounts he was brilliant and gracious, a humanist with a gift for explaining his passion in graceful prose.

As a scientist he expanded the curative power of medicine when he successfully grafted “foreign” cells onto an animal still in utero, overcoming the problem of tissue rejection and opening up the field of immunology, including the ability to transplant organs from one individual to another.

He was a towering figure literally (he stood more than 6 feet tall) and figuratively, with students and friends around the world. Medawar wrote for the general public and was frequently invited to lecture and review.

“The Threat and the Glory: Reflections on Science and Scientists” is a posthumous collection of these articles and talks, some published before, others in print for the first time, all reflecting Medawar’s thoughts about science from the late 1950s until his death in 1987.

The 23 chapters range from fascinating “bench” stories of life in the lab, such as “The Strange Case of the Spotted Mice,” to a defense of the use of animals in research, six talks about “The Future of Man” delivered in 1959, and thoughts on dying, written between the strokes that incapacitated him but never completely prevented him from working.

As director of Britain’s National Institute for Medical Research, Medawar was often attacked by antivivisectionists. In the Paget Lecture in 1966, sponsored by the Research Defense Society, he addressed the use of experimental animals to enlarge medical knowledge.

Trained initially as a zoologist, Medawar was interested in evolutionary theory, especially the question of “fitness” in humans as well as animals. He thought of the animal rights sentiment in Britain as a recent trend--going back only 170 years--and faulted rights advocates for their sentimentality.

Then turning to the National Institute for Medical Research, where animals were bred and cared for by professionals familiar with their genetic composition and history, he supported what he referred to as “the 3 R’s of humane laboratory practice: Reduction, Refinement and Replacement”: reduction in numbers of animals used, refinement of experimental techniques, and their eventual replacement by tissue culture and computer simulation.

What is interesting for an American reader is the directive that in Britain animals can be used only when an immediate medical application is foreseen. Medawar found this restriction cramping. He emphasized the need for pure research, which would necessitate the use of more animals in the laboratory. He acknowledged the right of the general public to know about all animal research but wanted this research expanded to include any that would advance human welfare. And Medawar defined human welfare as more than physical health, but as the satisfaction of what he saw as a species-specific compulsion to explore the world.

Critics today, including scientists like Jane Goodall, suggest that the satisfaction of human curiosity is not the unmitigated good that has been preached since the Enlightenment, and that science can overstep its role. Medawar would adamantly disagree.

“It is too late now to adopt an intellectually pastoral existence . . . too late to cease to be ambitious.” And for this ambition to be satisfied, he maintained, living animals will be needed for research, albeit in declining numbers, for some time to come.

Medawar was an unabashed “speciesist” who made no apologies for his championship of Homo sapiens. In “The Future of Man,” six talks for the Reith lectures of 1959 that compose a third of this volume, Medawar pondered our evolutionary future, including the possibility that advances in medicine may be regressive, enabling the supposedly “unfit” to reproduce “and the dangers, real or imagined, of the genetic deterioration brought about by the propagation of the genetically unfit.”

These fears are part of an English scientific preoccupation with degeneration, articulated earlier in the century by the eugenicist Karl Pearson and much disputed by later scientists.

This chapter is filled with interesting facts about population changes--that older mothers tend to have daughters rather than sons--and that populations that consciously limit family size tend to complete their families while young, and thus reduce the average gap between generations. What would he have made of the tendency today for late marriages and delayed births, which also result in small families but with increased gaps between generations?

Medawar was apparently a charismatic figure, as witnessed in the foreword by Lewis Thomas. His inspirational thoughts in “The Life Instinct and Dignity in Dying” suggest why he elicited such broad affection. The volume is, inevitably, a mixed bag, rich in good scientific storytelling, but also already a period-piece, reflecting biases of place and class.

Next: Jonathan Kirsch reviews “The Legacy: The Vietnam War in the American Imagination,” edited by D. Michael Shafer (Beacon Press).