"For weekend times when there is nothing new in the house to read, and it is raining and nothing much to think about or write about, and the afternoon stretches ahead all bleak and empty," writes Lewis Thomas, "there is nothing like Montaigne to make things better."

So too, I think, there is nothing like Dr. Lewis Thomas to make things better."

I came to his words this summer the way he went to Montaigne -- on rainy weekend afternoons. I didn't expect much from the essay book, "The Medusa and the Snail." He had been described to me as a scientist who could write. This was surely a feat, like Samuel Johnson's dancing dog, but not necessarily a talent.

Scientists, after all, rarely even use our language. They speak in strange tongues and write in scientific journalese. They seem to be as interested in sharing their world and its mysteries with the laity as the medieval churchmen were in educating the masses in Latin. They wanted faith, not comprehension.

Moreover, the writers and scientists I know grew up in a society that separated us from them onto separate tracks. "They" went into math and "we went into English; they went into science and we went into humanities, gathering along the way a clear prejudice that the sciences were, somehow or other, less humane.

The result of this training has been a deep and painful gap in understanding. Without words, our society as a whole has become suspicious of scientists. We see more Mr. Hydes than Dr. Jekylls, are more conscious of carcinogens than cures, more aware of the possibility of DNA disasters than DNA discoveries.

The world scientists live in seems as separate from ours as a laboratory from a field.

Which is why Thomas, my rainy day author, is such a joy. Here is a biologist who turns a keen eye from the microscope to the macrocosm and back. He ranges from bacteria to Bach, from cells to selves. He ruminates on the goldfish in a New York "pond" and the beavers in a zoo, on our punctuation and our hypochondria.

Thomas writes that, "Much of today's public anxiety about science is the apprehension that we may forever be overlooking the whole by an endless obsessive preoccupation with the parts." But he uses biology not as a box, but as a basis for understanding the whole. Unlike the hermits of his profession, he comes from science to society, chronicling the the path in a graceful journal.

When he comments on our obsession with self, the doctor, who is the head of a cancer institute, gently notes: "Uniqueness is so commonplace a property of living things that there is really nothing at all unique about it." He goes on to tell about the uniqueness of a fish, a mouse, an anemone.

Later, noting all the furor about the "test-tube" baby, he remarks that the real fuss should be about the reproductive cell itself, not about the dish it was mixed in. "People ought to be walking around all day, all through their waking hours, calling to each other in endless wonderment, talking of nothing else except that cell;"

Perhaps because he went to medical school in the late 1930s when, for the first time, as he notes, doctors were actually curing patients, Thomas is an optimist in a sea of pessimists.

"As a people, we have become obsessed with health. There is something fundamentally, radically unhealthy about this. We do not seem to be seeking more exuberance in living as much as staving off failure, putting off dying. We have lost confidence in the human body."

But everything gives him reason to hope: The music of Bach, the capacity of the mind to cure a wart, the ordinariness of Montaigne. Thomas is a man who thinks about thinking, worries about worrying, a scientist who loves words, a very special mind wandering through the world observing and sharing.

So, if you have some "weekend times when there is nothing new in the house to read, and it is raining and nothing much to think about or write about, and the afternoon stretches ahead all bleak and empty," you could do worse than read his spirited defense of science: "I cannot begin to guess at all the causes of our cultural sadness, not even the most important ones, but I can think of one thing that is wrong with us and eats away at us: We do not know enough about ourselves.

"For as long as we are bewildered by the mystery of ourselves, and confused by the strangeness of our uncomfortable connection to all the rest of life, and dumbfounded by the inscrutability of our own minds, we cannot be said to be healthy animals in today's world. We need science, more and better science . . . for the hope of wisdom which our kind of culture must acquire for its survival."