Maintaining the flow of oxygen and nutrients to the brain was essential – but it wouldn’t reverse the deterioration which had already taken place. The true catalysts of revival were the billions of liposomes – microscopic drug capsules made from lipid membranes – being infused along with the ersatz blood. One key protein embedded in the membrane unlocked the blood-brain barrier, enabling the liposomes to burrow out of the cerebral capillaries into the interneural space. Other proteins caused the membrane itself to fuse with the cell wall of the first suitable neuron it encountered, disgorging an elaborate package of biochemical machinery to reenergize the cell, mop up some of the molecular detritus of ischemic damage, and protect against the shock of re-oxygenation.

Other liposomes were tailored for other cell types: muscle fibers in the vocal fold, the jaw, the lips, the tongue; receptors in the inner ear. They all contained drugs and enzymes with similar effects: hijacking the dying cell and forcing it, briefly, to marshal its resources for one final – unsustainable – burst of activity.

Revival was not resuscitation pushed to heroic extremes. Revival was permitted only when the long-term survival of the patient was no longer a consideration, because every method which might have achieved that outcome had already failed.

The pathologist glanced at a display screen on the equipment trolley. I followed her gaze; there were wave traces showing erratic brain rhythms, and fluctuating bar graphs measuring toxins and breakdown products being flushed out of the body. Lukowski stepped forward expectantly. I followed him.

The assistant hit a button on a keypad. The victim twitched and coughed blood – some of it still his own, dark and clotted. The wave traces spiked, then became smoother, more periodic.

Lukowski took the victim’s hand and squeezed it – a gesture which struck me as cynical, although for all I knew it might have reflected a genuine compassionate impulse. I glanced at the bioethicist. Vis T-shirt now read CREDIBILITY IS A COMMODITY. I couldn’t decide if that was a sponsored message or a personal opinion.

Lukowski said, “Daniel? Danny? Can you hear me?” There was no obvious physical response, but the brain waves danced. Daniel Cavolini was a music student, nineteen years old. He’d been found around eleven, bleeding and unconscious, in a corner of the Town Hall railway station – with watch, notepad, and shoes still on him, unlikely in a random mugging gone wrong. I’d been hanging out with the homicide squad for a fortnight, waiting for something like this. Warrants for revival were issued only if the evidence favored the victim being able to name the assailant; there was little prospect of obtaining a usable verbal description of a stranger, let alone an identikit of the killer’s face. Lukowski had woken a magistrate just after midnight, the minute the prognosis was clear.