‘Eyes shut, mouth open,’ he demonstrated, swerving into Lang, who jumped nimbly out of his way. ‘Look at you; you’re doing it even now. Believe me, Lang, you’re not awake, you’re somnambulating.’ He called back to Morley, ‘Agreed, Doctor?’

Morley swallowed a yawn. ‘Well, if he is, that makes two of us.’ He followed them along the corridor, doing his best to stay awake, feeling as if he, and not the three men in front of him, had been without sleep for the last three weeks.

Though the Clinic was quiet, at Neill’s orders all lights along the corridors and down the stairway had been left on. Ahead of them two orderlies checked that windows they passed were safely screened and doors were shut. Nowhere was there a single darkened alcove or shadow-trap.

Neill had insisted on this, reluctantly acknowledging a possible reflex association between darkness and sleep: ‘Let’s admit it. In all but a few organisms the association is strong enough to be a reflex. The higher mammals depend for their survival on a highly acute sensory apparatus, combined with a varying ability to store and classify information. Plunge them into darkness, cut off the flow of visual data to the cortex, and they’re paralysed. Sleep is a defence reflex. It lowers the metabolic rate, conserves energy, increases the organism’s survival-potential by merging it into its habitat…

On the landing halfway down the staircase was a wide, shuttered window that by day opened out on to the parkscape behind the Clinic. As he passed it Gorrell stopped. He went over, released the blind, then unlatched the shutter.

Still holding it closed, he turned to Morley, watching from the flight above.

‘Taboo, Doctor?’ he asked.

Morley looked at each of the three men in turn. Gorrell was calm and unperturbed, apparently satisfying nothing more sinister than an idle whim. Lang sat on the rail, watching curiously with an expression of clinical disinterest. Only Avery seemed slightly anxious, his thin face wan and pinched. Morley had an irrelevant thought: four a.m. shadow — they’ll need to shave twice a day. Then: why isn’t Neill here? He knew they’d make for a window as soon as they got the chance.

He noticed Lang giving him an amused smile and shrugged, trying to disguise his uneasiness.

‘Go ahead, if you want to. As Neill said, the wires are cut.’

Gorrell threw back the shutter, and they clustered round the window and stared out into the night. Below, pewter-grey lawns stretched towards the pines and low hills in the distance. A couple of miles away on their left a neon sign winked and beckoned.

Neither Gorrell nor Lang noticed any reaction, and their interest began to flag within a few moments. Avery felt a sudden lift under the heart, then controlled himself. His eyes began to sift the darkness; the sky was clear and cloudless, and through the stars he picked out the narrow, milky traverse of the galactic rim. He watched it silently, letting the wind cool the sweat on his face and neck.

Morley stepped over to the window and leaned his elbows on the sill next to Avery. Out of the corner of his eye he carefully waited for any motor tremor — a fluttering eyelid, accelerated breathing that would signal a reflex discharging. He remembered Neill’s warning: ‘In Man sleep is largely volitional, and the reflex is conditioned by habit. But just because we’ve cut out the hypothalamic loops regulating the flow of consciousness doesn’t mean the reflex won’t discharge down some other pathway. However, sooner or later we’ll have to take the risk and give them a glimpse of the dark side of the sun., Morley was musing on this when something nudged his shoulder.

‘Doctor,’ he heard Lang say. ‘Doctor Morley.’

He pulled himself together with a start. He was alone at the window. Gorrell and Avery were halfway down the next flight of stairs.

‘What’s up?’ Morley asked quickly.

‘Nothing,’ Lang assured him. ‘We’re just going back to the gym.’ He looked closely at Morley. ‘Are you all right?’

Morley rubbed his face. ‘God, I must have been asleep.’ He glanced at his watch. Four twenty. They had been at the window for over fifteen minutes. All he could remember was leaning on the sill. ‘And I was worried about you.’

Everybody was amused, Gorrell particularly. ‘Doctor,’ he drawled, ‘if you’re interested I can recommend you to a good narcotomist.’

After five o’clock they felt a gradual ebb of tonus from their arm and leg muscles. Renal clearances were falling and breakdown products were slowly clogging their tissues. Their palms felt damp and numb, the soles of their feet like pads of sponge rubber. The sensation was vaguely unsettling, allied to no feelings of mental fatigue.

The numbness spread. Avery noticed it stretching the skin over his cheekbones, pulling at his temples and giving him a slight frontal migraine. He doggedly turned the pages of a magazine, his hands like lumps of putty.

Then Neill came down, and they began to revive. Neill looked fresh and spruce, bouncing on the tips of his toes.

‘How’s the night shift going?’ he asked briskly, walking round each one of them in turn, smiling as he sized them up. ‘Feel all right?’

‘Not too bad, Doctor,’ Gorrell told him. ‘A slight case of insomnia.’

Neill roared, slapped him on the shoulder and led the way up to- the Surgery laboratory.

At nine, shaved and in fresh clothes, they assembled in the lecture room. They felt cool and alert again. The peripheral numbness and slight head torpor had gone as soon as the detoxication drips had been plugged in, and Neil told them that within a week their kidneys would have enlarged sufficiently to cope on their own.

All morning and most of the afternoon they worked on a series of IQ, associative and performance tests. Neill kept them hard at it, steering swerving blips of light around a cathode screen, juggling with intricate numerical and geometric sequences, elaborating word-chains.

He seemed more than satisfied with the results.

‘Shorter access times, deeper memory traces,’ he pointed out to Morley when the three men had gone off at five for the rest period. ‘Barrels of prime psychic marrow.’ He gestured at the test cards spread out across the desk in his office. ‘And you were worried about the Unconscious.

Look at those Rorschachs of Lang’s. Believe me, John, I’ll soon have him reminiscing about his foetal experiences.’

Morley nodded, his first doubts fading.

Over the next two weeks either he or Neil! was with the men continuously, sitting out under the floodlights in the centre of the gymnasium, assessing their assimilation of the eight extra hours, carefully watching for any symptoms of withdrawal. Neil! carried everyone along, from one programme phase to the next, through the test periods, across the long hours of the interminable nights, his powerful ego injecting enthusiasm into every member of the unit.

Privately, Morley worried about the increasing emotional overlay apparent in the relationship between Neill and the three men. He was afraid they were becoming conditioned to identify Neil! with the experiment. (Ring the meal bell and the subject salivates; but suddenly stop ringing the bell after a long period of conditioning and it temporarily loses the ability to feed itself. The hiatus barely harms a dog, but it might trigger disaster in an already oversensitized psyche.)

Neil! was fully alert to this. At the end of the first two weeks, when he caught a bad head cold after sitting up all night and decided to spend the next day in bed, he. called Morley into his office.

‘The transference is getting much too positive. It needs to be eased off a little.’

‘I agree,’ Morley said. ‘But how?’

‘Tell them I’ll be asleep for forty-eight hours,’ Neill said. He picked up a stack of reports, plates and test cards and bundled them under one arm. ‘I’ve deliberately overdosed myself with sedative to get some rest. I’m worn to a shadow, full fatigue syndrome, load-cells screaming. Lay it on.’