ONE SCORPIO RISING Great and Good are seldom the same man. -WINSTON CHURCHILL A scorpion and a frog are sitting on the bank of a river, and both need to get to the other side. "Hello, Mr. Frog!" calls the scorpion through the reeds. "Would you be so kind as to give me a ride on your back across the water? I have important business to conduct on the other side. And I cannot swim in such a strong current." The frog immediately becomes suspicious. "Well, Mr.

Scorpion," he replies, "I appreciate the fact that you have important business to conduct on the other side of the river. But just take a moment to consider your request. You are a scorpion. You have a large stinger at the end of your tail. As soon as I let you onto my back, it is entirely within your nature to sting me." The scorpion, who has anticipated the frog's objections, counters thus: "My dear Mr. Frog, your reservations are perfectly reasonable. But it is clearly not in my interest to sting you.

I really do need to get to the other side of the river. And I give you my word that no harm will come to you." The frog agrees, reluctantly, that the scorpion has a point. So he allows the fast-talking arthropod to scramble atop his back and hops, without further ado, into the water. At first all is well. Everything goes exactly according to plan. But halfway across, the frog suddenly feels a sharp pain in his back-and sees, out of the corner of his eye, the scorpion withdraw his stinger from his hide. A deadening numbness begins to creep into his limbs.

"You fool!" croaks the frog. "You said you needed to get to the other side to conduct your business. Now we are both going to die!" The scorpion shrugs and does a little jig on the drowning frog's back. "Mr. Frog," he replies casually, "you said it yourself. I am a scorpion. It is in my nature to sting you." With that, the scorpion and the frog both disappear beneath the murky, muddy waters of the swiftly flowing current.

And neither of them is seen again. Bottom Line During his trial in 1980, John Wayne Gacy declared with a sigh that all he was really guilty of was "running a cemetery without a license." It was quite a cemetery. Between 1972 and 1978, Gacy had raped and murdered at least thirty-three young men and boys (with an average age of about eighteen) before stuffing them into a crawl space beneath his house. One of his victims, Robert Donnelly, survived Gacy's attentions, but was tortured so mercilessly by his captor that, at several points during his ordeal, he begged him to "get it over with" and kill him. Gacy was bemused. "I'm getting around to it," he replied. I have cradled John Wayne Gacy's brain in my hands.

Following his execution in 1994 by lethal injection, Dr. Helen Morrison-a witness for the defense at his trial and one of the world's leading experts on serial killers-had assisted in his autopsy in a Chicago hospital, and then driven back home with his brain jiggling around in a glass jar on the passenger seat of her Buick. She'd wanted to find out whether there was anything about it-lesions, tumors, disease-that made it different from the brains of normal people. Tests revealed nothing unusual. Several years later, over coffee in her office in Chicago, I got to chatting with Dr. Morrison about the significance of her findings, the significance of finding … nothing. "Does this mean," I asked her, "that we're basically all psychopaths deep down? That each of us harbors the propensity to rape, kill, and torture? If there's no difference between my brain and the brain of John Wayne Gacy, then where, precisely, does the difference lie?" Morrison hesitated for a moment before highlighting one of the most fundamental truths in neuroscience. "A dead brain is very different from a living one," she said.

"Outwardly, one brain may look very similar to another, but function completely differently. It's what happens when the lights are on, not off, that tips the balance. Gacy was such an extreme case that I wondered whether there might be something else contributing to his actions-some injury or damage to his brain, or some anatomical anomaly. But there wasn't. It was normal. Which just goes to show how complex and impenetrable the brain can sometimes be, how reluctant it is to give up its secrets. How differences in upbringing, say, or other random experiences can cause subtle changes in internal wiring and chemistry which then later account for tectonic shifts in behavior." Morrison's talk that day of lights and tectonic shifts reminded me of a rumor I once heard about Robert Hare, professor of psychology at the University of British Columbia and one of the world's leading authorities on psychopaths.

Back in the 1990s, Hare submitted a research paper to an academic journal that included the EEG responses of both psychopaths and non-psychopaths as they performed what's known as a lexical decision task. Hare and his team of coauthors showed volunteers a series of letter strings, and then got them to decide as quickly as possible whether or not those strings comprised a word. What they found was astonishing. Whereas normal participants identified emotionally charged words like "c-a-n-c-e-r" or "r-a-p-e" more quickly than neutral words like "t-r-e-e" or "p-l-a-t-e," this wasn't the case with psychopaths. To the psychopaths, emotion was irrelevant. The journal rejected the paper. Not it turned out, for its conclusions, but for something even more extraordinary. Some of the EEG patterns, reviewers alleged, were so abnormal they couldn't possibly have come from real people.

But of course they had. Intrigued by my talk with Morrison in Chicago about the mysteries and enigmas of the psychopathic mind-indeed, about neural recalcitrance in general-I visited Hare in Vancouver. Was the rumor true? I asked him. Had the paper really been rejected? If so, what was going on? "There are four different kinds of brain waves," he told me, "ranging from beta waves during periods of high alertness, through alpha and theta waves, to delta waves, which accompany deep sleep. These waves reflect the fluctuating levels of electrical activity in the brain at various times. In normal members of the population, theta waves are associated with drowsy, meditative, or sleeping states. Yet in psychopaths they occur during normal waking states-even sometimes during states of increased arousal … "Language, for psychopaths, is only word deep. There's no emotional contouring behind it.

A psychopath may say something like 'I love you,' but in reality, it means about as much to him as if he said 'I'll have a cup of coffee.' … This is one of the reasons why psychopaths remain so cool, calm, and collected under conditions of extreme danger, and why they are so reward-driven and take risks. Their brains, quite literally, are less 'switched on' than the rest of ours." I thought back to Gacy and what I'd learned from Dr. Morrison. "Kiss my ass," he'd said as he entered the death chamber. Normal on the outside (Gacy was a pillar of his local community, and on one occasion was even photographed with First Lady Rosalynn Carter), he camouflaged his inner scorpion with an endearing cloak of charm. But it was entirely in his nature to sting you-as much as it was to convince you that he wouldn't.

Talking the Walk Fabrizio Rossi is thirty-five years old, and used to be a window cleaner. But his predilection for murder eventually got the better of him. And now, would you believe, he "does" it for a living. As we stand next to each other on a balmy spring morning, poking uneasily around John Wayne Gacy's bedroom, I ask him what the deal is. What is it about psychopaths that we find so irresistible? Why do they fascinate us so much? It's definitely not the first time he's been asked. "I think the main thing about psychopaths," says Rossi, "is the fact that on the one hand they're so normal, so much like the rest of us-but on the other, so different. I mean, Gacy used to dress up as a clown and perform at children's parties … That's the thing about psychopaths. On the outside they seem so ordinary.

Yet scratch beneath the surface, peek inside the crawl space, as it were, and you never know what you might find." We are not, of course, in Gacy's actual bedroom, But rather, in a mocked-up version of it that comprises an exhibit in what must surely be a candidate for the grisliest museum in the world: the Museum of Serial Killers in Florence. The museum is located on Via Cavour, a ritzy side street within screaming distance of the Duomo. And Fabrizio Rossi curates it. The museum is doing well. And why wouldn't it? They're all there, if you're into that kind of thing. Everyone from Jack the Ripper to Jeffrey Dahmer, from Charles Manson to Ted Bundy. Bundy's an interesting case, I tell Rossi.

An eerie portent of the psychopath's hidden powers. A tantalizing pointer to the possibility that, if you look hard enough, there might be more in the crawl space than just dark secrets.