“Who funded his research?” Burton asked.

“His club.”

“It being?”

“The—the—the League of Enochians.”

“I’ve not heard of it.”

“I have,” Trounce put in. “It occupies a building on the corner of Mildew Street where it joins Saint Martin’s Lane.”

“So this club has an interest in Eugenics?”

Darwin stopped and thumped his stick into the ground. “Damn Eugenics!” Burton and Trounce looked at him in surprise, taken aback at the show of anger from a man who had thus far appeared mild in temperament.

“Francis is family,” Darwin continued, “but the manner in which that bloody club encouraged him to appropriate and pervert my research is—is—is absolutely foul. I cannot forgive that he allowed himself to be so swayed.”

Burton put out a hand and touched the scientist’s arm. “Mr. Darwin, perhaps this would make rather more sense to me if I understood the nature of your work.”

They resumed their walk. Darwin snorted. “Sir Richard, I’ve been attempting to articulate my theory since 1837—”

Without thinking, the explorer blurted, “The beginning of the Great Amnesia!”

Darwin peered at him curiously. “W-w-what of it?”

“I—” Burton stopped, considered, and went on, “I wonder how it affected you, that is all.”

“The same way it affected everyone else. In 1840, I had to extensively review three years’ worth of research and notes, and it all seemed oddly unfamiliar to me. However, it made sense, and as a matter of fact, in going through it, my enthusiasm was renewed, my ideas clarified, and I was set upon a course that led me to my current position.”

“Which is?”

They reached the corner of the field and followed the path as it curved sharply to the right.

“W-w-which is that, having fully developed my hypothesis, I have, since ’fifty-seven, been writing a detailed account of it. However, a year ago, to my dismay, I received a paper from a fellow scientist—Alfred Wallace—that dealt with the very same matter. I thought I had been f-f-forestalled, but my publisher insisted that if I produced an abstract of my dissertation, it could be published before Wallace pipped me to the post. I have thus been struggling for thirteen months to condense my w-w-work. And now you ask me to explain it in a few sentences!”

Burton glanced up at the blue, cloud-spotted sky. He thought he could hear the distant clatter of approaching engines.

“I’m trying to understand why Burke and Hare took Mr. Galton from the asylum,” he said, “and can only surmise that it has something to do with Eugenics. If he developed that science by subverting your own research, then I must have some grasp of your theory in order to comprehend his version of it.”

Darwin stopped, poked the tip of his cane into a blackberry bush, and used it to lift a clump of overripened berries. He bent and scrutinised them closely.

“Very well,” he muttered. “Let us put it this way. Our world has limited resources, thus every individual of every species is engaged in intense competition for them. Do you follow?”

“I do, sir.”

“Within any given species, individuals vary in their t-t-traits. One might have better eyesight than another, or sharper teeth, or a brighter-coloured skin, or a better ability to endure cold, and so on and so forth. Yes?”

“Yes.”

“Depending on local conditions, some of these traits will aid survival, while others will not. The individuals that possess the advantageous ones will generally eat better, live longer, and thus breed more successfully, passing their attributes on to their offspring. Over t-t-time, therefore, the species as a whole will retain beneficial characteristics while breeding out the weaknesses.”

Darwin suddenly turned away from the bush, straightened, and faced Burton and Trounce. He raised a finger. “But, but, but! Environmental conditions are far from stable. There are ongoing geological and climactic upheavals and alterations. So it is not the strongest of the species that survives, nor is it the most intelligent. It is the one that is most adaptable to change—the one that will most quickly develop and adopt new strengths and abilities even to the point where, eventually, and if necessary, it will transmute into a new species entirely. Gentlemen, I have called this principle, by which each slight variation, if useful, is preserved, by the term of natural selection.”

He lowered his hand and regarded them, blinking, and panting slightly after what had become an increasingly impassioned speech.

Burton heard the engines he’d noticed before draw much closer. They idled, and he looked toward Down House, convinced they’d halted at the Darwin residence.

Trounce quietly cleared his throat and said, “Um. Where does God fit into your theory, Mr. Darwin?”

The scientist winced. He set off again along the path. They walked with him.

“My poor Emma,” he said. “My w-w-wife has laboured assiduously to assist me in preparing my thesis for publication, but in contemplating it, she has found, as did I, that her faith is eroded. She c-c-clings to it, Detective Inspector, whereas I—well, I cannot persuade myself that a beneficent and omnipotent God would have designedly created, for example, parasitic wasps with the express intention of their feeding within the living bodies of caterpillars. There is no other conclusion to draw than that the universe we observe has precisely the properties we would expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind, pitiless indifference.”

Burton, who’d so often drawn this same conclusion but been unable to accurately express it or identify incontrovertible evidence to support it, looked at Darwin with admiration. “Sir, if, as you said, my solving of the Nile question was as impressive a feat as you have ever heard of, then I suggest you hold your own theory to a mirror, for the elegant explanation you have just given, though you might consider it curtailed in the extreme, is enough to convince me that you are on the brink of transforming the world of man. That a human brain can produce so profound an insight is—” He stopped, lost for words.

Darwin supplied them. “Bloody dangerous.”

“Dangerous?”

“You wanted to know what my half-cousin has done with my theory, Sir Richard. I will tell you. He has proposed a human intercession in the processes of natural selection. Rather than allow the successes and failures of survival to dictate the shape of species, he wants to decide for himself which strengths to breed and which weaknesses to eliminate.”

“But how is that different from the actions of, say, a pigeon breeder or a cattle farmer?” Burton asked.

“It is different because he intends that it be applied to the human species. Furthermore, rather than allowing physical characteristics to develop over long periods of time and in response to the environment, he advocates surgical intervention to hasten the process of evolution.”

“The warden at the hospital suggested that Mr. Galton believed that men can be made gods.”

“If, by gods, you mean beings with physical and mental powers that far exceed what is currently natural to us, then yes, that is what Francis seeks.”

Darwin, Burton, and Trounce all jerked their heads around toward the house.

“Was that a scream?” Trounce said.

“Emma!” Darwin gasped.

They left the path and started running across the grass. Burton rapidly drew ahead while Trounce helped the scientist along. The explorer heard children shouting and crying. Angling to the right, he rejoined the path where it entered the garden, raced past the white snakeroot flowers, and burst out of the bushes onto the lawn of Down House.

There were two steam spheres at the side of the residence, both empty but with their engines still ticking over and vapour curling from their funnels. Two of the Darwin children were lying dead or unconscious on the ground. The others were screaming in panic and running back and forth. A short, ape-like man had his arms around Mrs. Darwin, pinning her arms to her sides. She was facing away from him, and as Burton came into her line of sight, she saw him and yelled, “Get them away! Save my children! Save my children!”