Monkey’s Uncle : DARWIN: The Life of a Tormented Evolutionist <i> By Adrian Desmond and James Moore (Warner Books: $35; 808 pp.) </i>

“Darwin,” the excellent new biography of one of the founding fathers of modern science, sometimes seems less a portrait of an intellectual pioneer than of a mild-mannered Dr. Frankenstein ghoulishly fingering the decomposing body parts of specimens sent to him from all over the globe.

Living in a quaint country vicarage stuffed to the rafters with the pickled remains of pigeons, ducks, horses, dogs, fish, leeches and barnacles, Darwin spent the better part of his days experimenting on things like carnivorous sundew plants, which he first fattened on a rich diet of roast beef, hard-boiled eggs and coffee, and then poisoned with urine, saliva, strychnine, morphine and cobra’s venom. He dug dung beetles out of cow patties, dyed pigeons magenta, painted the wings of dragonflies and even threatened to cut out the eyes of a peacock’s tail with a pair of scissors in order to see if the absence of this distinctive pattern interfered with the bird’s mating rituals.

He was such a fanatical naturalist that once, after catching two rare insects in either hand while pursuing his favorite pastime of “entomologizing,” he caught a third by popping one in his mouth. It was a magnificent bombardier beetle, which promptly squirted him like a skunk with a noxious excretion he spat out along with the bug, losing all three in the confusion that ensued as he scrambled around on all fours in search of the day’s precious finds.

A zealot even as a young bachelor, he was so immersed in the jargon of science that he spoke about the prospect of marriage in the most austere and unsentimental terms possible, saying that “as for a wife, that most interesting specimen in the whole series of vertebrate animals, Providence only know(s) whether I shall ever capture one or be able to feed her if caught.”

Documenting more than just the life of one astonishingly prolific scientist and thinker, Adrian Desmond and James Moore give us the social history of an entire age, representing the evolution not only of a species but also of a profession. They are remarkably sensitive to the incongruities of an era in British history that could at once engage in the high camp of presenting to the Duchess of Cambridge an orangutan named Jenny dressed as a blushing debutante, and then recoil violently from the idea that mankind had evolved from the ancestors of this very same animal.

The son of a famous doctor and a member of a family that included some of the century’s most notorious free-thinkers, Darwin was one of the last of a long line of rich amateurs and dilettante naturalists, a moneyed group of beetle collectors, “bugologists” and sleepy Anglican clerics whose scientific hobbies were inextricably linked with their religious beliefs. Although his wealthy father wanted him to become a clergyman, the young Darwin soon broke rank with these benighted pastoralists, whom he viewed as nothing more than pious dabblers. Instead he joined the new group of atheistic upstarts who were intent on dissolving the unholy alliance of religion and science in hopes of grounding their various disciplines in more systematic and empirically based methods of analysis.

While studying medicine at Edinburgh University, Darwin came under the spell of his first mentor, the charismatic cynic Robert Grant, an atheist sponge expert who turned him on to the mysteries of sea-slugs and presided over his first less-than-momentous scientific breakthroughs: the discovery of the eggs of a skate leech and the larvae of a sea-mat.

Waxing enthusiastic over things like tentacled polyps or--even more exhilarating--Grant’s discovery of the pancreas of a mollusk, Darwin soon abandoned medicine altogether and took a position as the resident naturalist on the Beagle, the ship he made famous by gathering together in the course of a five-year voyage a spectacular collection of 1,529 species (at least one of which he accidentally cooked and ate for dinner, managing to salvage only the leftover for posterity, a mauled carcass consisting solely of the head, neck, legs, and one wing).

In addition to offering an exciting intellectual history of this most seminal period in the development of modern science, Desmond and Moore have captured the gripping psychological dimension of Darwin’s struggles to reconcile himself to the radical implications of his own ideas. The chief difficulty lay in the way the theory of evolution degraded man from his position of preeminence in the Great Chain of Being to something as inconsequential as a distant relative of an amphibious hermaphrodite, a “vile . . . molluscous bisexual animal with a vertebra only & no head!!”

The biography provides a portrait of a scientist whose oppressive sense of social propriety outstripped his own genius, who was far more intelligent than he was courageous, and who struggled valiantly for many years to disassociate himself from the very audience that would have been most receptive to his ideas--the growing numbers of the intellectually disenfranchised, a motley crew of disgraced doctors, heretics, libertines, dissenters and atheists whom the stodgy and somewhat snobbish Darwin dismissed as inflammatory extremists. Avoiding such people by hiding away in a small circle of family and friends, he kept his theory of the survival of the fittest closely under wraps until the threat of being beaten to the punch by other scientists spurred into action this demure and self-effacing beetle collector, who still longed for nothing more than a bourgeois existence living with “the Little Wife in the Little Parsonage.”

And with good reason, because Emma Wedgwood, the Little Wife, quickly assumed the role she was to play for over 40 years as a dedicated and infinitely forbearing nursemaid of her frail husband. A hypochondriac of monumental proportions, Darwin suffered from a chronic intestinal disorder that made his life one long bout of spasmodic vomiting, which he controlled by submitting to various quack cures--like anesthetizing his spine with packs of ice or steeping himself with religious fervor in the medicinal waters of Dr. James Gully’s “hydrophatic” spa.

As his family grew at an alarmingly fast pace, Darwin soon realized that he had passed his illness on to many of his 10 children, several of whom he watched sicken and die in such agonizing pain that their suffering provided tragic confirmation of the disheartening truth of his own discoveries. As the offspring of a whole series of incestuous first-cousin marriages between the Darwins and the Wedgwoods, Charles’ and Emma’s children were the product of several generations of inbreeding and thus, like the runts of a litter, were congenitally unsuited to survive the merciless process of cutthroat competition that their guilty father laid out so brilliantly in the book for which he is best known.

In “The Origin of Species,” which finally appeared in 1859 to thunderous applause, horrified disbelief and outraged attempts at vilification, Darwin claimed that the development of both plants and animals was the result of “natural selection,” a process in which random mutations in the offspring of a species enabled some individuals to adapt themselves to their environments more readily than others, thereby surviving in greater numbers and passing on to their children these invaluable assets.

Such a doctrine dealt a death blow to the antiquated world view of biological theists who looked at nature and its inhabitants as one great big happy family, like the animals stowed away in pairs on Noah’s Ark, each of which God, and not some vile molluscous bisexual, had individually crafted during the seven days described in Genesis. In contrast to this vision of nature as a peaceable kingdom comprising a tidy menagerie of flawless specimens, Darwin proposed his own rather less hospitable view of a nature in which the species are pitted against each other, competing furiously for the limited resources available, either becoming extinct when they fail to adapt or overpopulating when they adapt all too well.

When the implications of this theory were extended to man, the whole controversy acquired an unsavory ideological cast, a revolutionary taint that the timid and socially complacent Darwin was far from ready to endorse himself. The vested interests of the aristocracy, passed on for generations by a decadent system of primogeniture, were suddenly seen not only as undemocratic but as unnatural. They thwarted the forces of competition that favored a meritocracy rather than an elite whose power, along with their silver spoons and coats of arms, were inherited.

The British nobility, already under pressure from the rising mercantile classes to relinquish their control of the government, suddenly saw their authority challenged in a startling new way by the meek and sickly Darwin who mopes around this fascinating biography. It was a challenge not lost on the disgusted Lady Aylesbury who, expressing her distaste for the heresy of evolution in a conversation reported by Darwin’s friend T. H. Huxley, threw down the gauntlet to the ignobly born novelist Charles Kingsley, who promptly picked it up and responded: “(W)hat can be more delightful to me, Lady Aylesbury, than to know that your Ladyship & myself sprang from the same toad stool?”