I was equally intrigued by what I was shown next. The curator guided me to a nearby corner and pushed aside a curtain. Behind it [Charles Darwin] had constructed a makeshift lavatory -- a porcelain washbasin set inside the raised floor. It was, the curator explained, a crude vomitory. Often during his morning writing, sometimes more than once, Darwin's stomach would seize up. He would thrust aside his writing board, rush over and retch into the basin.

As might be expected, Darwin was pilloried by the establishment of his day. Punch lampooned him in caricatures; the bishop of Oxford, Samuel "Soapy Sam" Wilberforce, ridiculed him from the pulpit, and Richard Owen, the great naturalist, attacked him in biting reviews. But undoubtedly nothing hurt Darwin as much as a letter sent to him by his wife, Emma, a devout Christian who worried that the views he was espousing would keep them separated through eternity. On it, he wrote: "When I am dead, know that many times I have kissed & cryed over this."

Were it not for a circle of influential thinkers around Darwin -- mostly notably Thomas Henry Huxley, who described himself as Darwin's bulldog -- his theory might have taken much longer to win the day. To them, Darwin's cause became greater than that of the theory alone; its ultimate acceptance represented the apotheosis of science itself, what they thought of as the ultimate victory for rationality, logic and materialism.