Peter had hoped to be able to watch it all dispassionately. It was just data, after all. But it was also Peggy, that brave and cheerful woman who had faced and beaten death once before, that woman who had held his hand as she passed from life into lifelessness.
The data continued to be plotted, and soon there were only a few patterns of light, like constellations on a foggy night, flickering on the screen. When the activity did stop, it did so without any apparent flourish. Not a bang. Not a whimper. Just nothingness.
Except…
What was that?
A tiny flash on the screen.
Peter reversed the recording, then played it back again at a much slower speed.
There was a minuscule pattern of purple lights — a persistent pattern, a pattern that kept firing over and over again.
And it was moving.
Neurons couldn’t really move, of course. They were physical entities. But the recorder was picking up the same pattern over and over again, just slightly displaced to the right each time. The recorder allowed for such displacements: neurons didn’t always fire in exactly the same way, and the brain was gelatinous enough that movements of the head and the pulsing of blood could slightly change the physical coordinates of a neuron. The pattern moving across the screen must have been propagating from neuron to adjacent neuron in steps small enough that the recorder mistook the individual increments for activity within the same neurons. Peter glanced at the scale bar at the bottom of the wall screen. The violet pattern, a complex knot like intestines made of neon tubes, had already shifted five millimeters, far more than any neuron could move within the brain except in the case of a major blow to the head, something Peggy Fennell had most assuredly not suffered.
Peter adjusted a control. The playback speeded up.
No doubt about it: the knot of violet pinpricks was moving to the right, pretty much in a straight line. It rotated a bit as it moved, like a tumbleweed blown by a desert wind. Peter stared in openmouthed wonder. It continued to move, passing over the corpus callosum into the other hemisphere, past the hypothalamus, and into the right temporal lobe.
Each part of the brain was normally reasonably isolated from the others, and the kinds of electrical waves typical of, say, the cerebral cortex were foreign to the cerebellum, and vice versa. But this tight knot of purple light was moving without changing its form through structure after structure.
An equipment malfunction, thought Peter. Oh, well. Nothing ever worked right the first time.
Except…
Except Peter couldn’t think of anything that would cause this kind of malfunction.
And still the pattern moved across the screen.
Peter tried to conjure up another explanation. Could a static discharge, perhaps from Peggy’s hair rubbing against the pillow, have caused this effect? Of course, hospital pillows are designed to be antistatic, precisely so they won’t mess up delicate recording equipment, and Peggy, after all, had had thinning, white hair. Besides, she’d been wearing his scanning skullcap.
No, it must be caused by something else.
The pattern was getting close to the outer edge of the brain. Peter wondered if it would dissipate on the convoluted surface of the cortex or maybe bounce back, spinning the other way, like a video game inside the head.
It did neither.
It reached the edge of the brain … and kept right on going, through the membrane that encased the brain.
Astonishing.
Peter touched some keys, overlaying an extrapolated outline of Mrs. Fennell’s head over the silhouette of her brain. He mentally kicked himself for not having done this sooner. It was obvious where the knot of light was heading.
Straight for the temple.
Straight for the thinnest part of her skull.
It continued along, through the bone, through the thin veneer of muscle that overlaid the skull.
Surely, thought Peter, it was going to break up. Yes, there are nerves at the temple; that’s why it hurts to be struck there. Yes, there are nerves in muscle tissue, too, including the jaw muscles that overlay the temple. And, yes, there are nerves shot through the lower layers of the skin. Even if the pattern had some form of cohesion, Peter expected to see a change here. The nerves outside the actual brain are much less densely packed. The pattern might balloon in size, drawn between the points of more diffuse neural tissue.
But it did not. It continued, exactly the same size, tumbling slowly end over end, through the muscle, through the skin, and—
Out. Past the sensor field.
It didn’t break up. It simply left. And yet it had held its cohesion. The pattern had remained intact right up to the moment the sensor web lost it.
Incredible, thought Peter. Incredible.
He scanned the wall, looking for signs of other active neural nets.
But there were none.
Peggy Fennell’s brain showed as an unblemished silhouette, devoid of electrical activity.
She was dead.
Dead.
And something had left her body.
Something had left her brain.
Peter felt his own head wheeling.
It couldn’t be.
It could not be.
He reversed the recording, played it back from a different angle.
Why had the knot of light moved from the left hemisphere to the right? The other temple had been closer.
Ah, but Peggy had been lying down, her head on her pillow. Her left temple had been facing into the pillow; it was her right one that had been exposed to air. Even though it had been farther away, it represented the easier escape route.
Peter played the recording back again and again. Different angles. Different plotting methods. Different color-encoding schemes. It didn’t matter; the result was the same. He compared the time-coded recordings to Peggy’s other vital signs — pulse, respiration, blood pressure. The knot of light left just after her heart stopped, just after she’d breathed her last.
Peter had found exactly what he was looking for: an unequivocal marker that life was now over, an indisputable sign that the patient was just meat, ready for organ harvesting.
Marker.
That wasn’t the right word, and he knew it. He was deliberately avoiding even thinking it. And yet, there it was, recorded by his own ultrasensitive instruments: the departure from her body of Peggy Fennell’s very own soul.
Peter knew that when he asked Sarkar to come at once to his house, Sarkar would do so. Peter couldn’t contain his excitement when Sarkar arrived. He was trying, and probably failing, to suppress a grin. He took Sarkar into his den, then played back the recording of Peggy Fennell’s death once more.
“You faked that,” said Sarkar.
“No, I didn’t.”
“Oh, come on, Peter.”
“Really. I haven’t even done any cleanup of the data. What you just saw is exactly what happened.”
“Play that last bit again,” said Sarkar. “One one-hundredth speed.”
Peter touched buttons.
“Subhanallah,” said Sarkar. “That’s incredible.”
“Isn’t it, though?”
“You know what that is, don’t you?” said Sarkar. “Right there, in crisp images. That’s her nafs — her soul — leaving her body.”
To his surprise, Peter found himself reacting negatively when he heard that idea said aloud. “I knew you were going to say that.”