Hester nodded. "The way I look at it is this," she said. "In a number of ways, you could view the twins as having divided a set of characteristics between them. Where an ordinary, healthy person will feel a whole range of different emotions, display a great variety of behaviors, the twins, you might say, have divided the range of emotions and behaviors into two and taken one set each. One twin is wild and given to physical rages; the other is indolent and passive. One prefers cleanliness; the other craves dirt. One has an endless appetite for food, the other can starve herself for days. Now, if this polarity-we can argue later about how consciously it has been adopted-is crucial to Adeline's sense of identity, it is unsurprising, is it not, if she suppresses within herself everything that in her view falls on Emmeline 's side of the boundary?" The question was rhetorical; she did not indicate to the doctor that he might speak, but drew in a measured breath and continued. "Now, consider the qualities in the girl in the mist. She listens to stories, is capable of understanding and being moved by a language that is not twin language. This suggests a willingness to engage with other people. But of the twins, which is it who has been allocated the job of engaging with others? Emmeline! And so Adeline must repress this part of her humanity."

Hester turned her head to the doctor and gave him the look that meant it was his turn to speak.

"It's a curious idea," he answered cautiously. "I should have thought the opposite, wouldn't you? That you could expect them to be more alike than dissimilar?"

"But we know from observation that that isn't the case," she countered briskly.

"Hmm."

She did not speak but let him consider. He stared at the empty wall, deep in thought, while she cast anxious glances in his direction, trying to divine the reception of her theory from his face. Then he was ready to make his pronouncement.

"While this idea of yours is an interesting one"-he put on a sympathetic smile to soften the effect of his discouragement-"I don't recall ever reading about such a division of character between twins in any of the authorities."

She ignored the smile and met his eyes levelly. "It isn't in the authorities, no. If it was going to be anywhere it would be in Lawson, and it isn't."

"You have read Lawson?"

"Of course. I would not dream of pronouncing an opinion on any subject without being sure of my references first." "Oh." "There is a reference to the Peruvian boy twins in Harwood that is suggestive, though he stops short of the full conclusion that might be drawn."

"I remember the example you mean… " He gave a little start. "Oh! I see the connection! Well, I wonder whether the Brasenby case study is of any relevance? "

"I haven't been able to obtain the full study. Can you lend it to me?"

So it began.

Impressed by the acuity of Hester's observations, the doctor lent her the Brasenby case study. When she returned it, there was a sheet of pithily expressed notes and questions attached. He, in the meantime, had obtained a number of other books and articles to complete his library on twins, recently published pieces, copies of work in progress from various specialists, foreign works. He found after a week or two that he could save himself time by passing these to Hester first, and reading for himself just the concise and intelligent summaries she produced. When between them they had read everything it was possible to read, they returned to their own observations. Both of them had compiled notes, his medical, hers psychological; there were copious annotations in his handwriting in the margins of her manuscript, but she had made even more notes on his, and sometimes attached her own cogent essays on separate pieces of paper.

They read; they thought; they wrote; they met; they discussed. This went on until they knew everything there was to know about twins, but there was still one thing they did not know, and it was the one thing that mattered.

"All this work," the doctor said one evening in the library, "all this paper. And we are still no nearer." He ran his hand through his hair in an agitated manner. He had told his wife he would be back by half past seven, and he was going to be late. "Is it because of Emmeline that Adeline represses the girl in the mist? I think the answer to that question lies outside the bounds of current knowledge." He sighed and tossed his pencil onto the desk, half annoyed, half resigned.

"You are quite right. It does." You could forgive her for sounding testy-it had taken him four weeks to reach the conclusion she could have given him at the beginning if he had only been willing to listen.

He turned to her.

"There is only one way to find out," she said quietly.

He raised an eyebrow.

"My experience and observations have led me to believe that there is scope for an original research project here. Of course, as a mere governess, I would have difficulty in persuading the appropriate journal to publish anything I produced. They would take one look at my qualifications and think I was nothing but a silly woman with ideas beyond her competence." She shrugged and cast her eyes down. "Perhaps they are right, and I am. All the same"-slyly she glanced up again-"for a man with the right background and knowledge, I am sure there is a meaty project there."

The doctor looked at first surprised, then his eyes turned misty. Original research! The idea was not so very preposterous. It struck him that at this moment, at the culmination of all the reading he had done in recent months, he must surely be the best-read doctor in the country on the subject of twins! Who else knew what he knew? And more to the point, who else had the perfect case study under his nose? Original research? Whyever not?

She let him indulge himself for a few minutes, and when she saw that her suggestion had taken root in his heart, murmured, "Of course, if you needed an assistant, I'd be glad to help in any way I could."

"Very kind of you." He nodded. "Of course, you've worked with the girls… Practical experience… Invaluable… Quite invaluable." He left the house and floated home on a cloud, where he failed to notice that his dinner was cold and his wife bad-tempered.

Hester gathered up the papers from the desk and left the room; her neat footsteps and firm closing of the door had the ring of satisfaction about them.

The library seemed empty, but it wasn't. Lying full-length on top of the bookcases, a girl was biting her nails and thinking. Original research.

Is it becauseofEmmeline that Adeline represses thegirl in the mist?

Didn't take a genius to figure out what was going to happen next.

They did it at night.

Emmeline never stirred as they lifted her from her bed. She must have felt herself safe in Hester's arms; perhaps she recognized the smell of soap in her sleep as she was carried out of the room and along the corridor. Whatever the reason, she didn't realize that night what was happening. Her awakening to the truth was hours away.

It was different for Adeline. Quick and sharp, she awoke at once to her sister's absence. Darted to the door but found it locked already by Hester's swift hand. In a flash she knew it all, felt it all. Severance. She didn't shriek, she didn't fling her fists against the door, she didn't claw at the lock with her nails. All the fight went out of her. She sank to the floor, collapsed into a little heap against the door, and that is where she stayed all night. The bare boards bit into her jutting bones, but she didn't feel the pain. There was no fire and her nightdress was thin, but she didn't feel the cold. She felt nothing. She was broken.

When they came for her the next morning, she was deaf to the key in the lock, didn't react when the opening door shunted her out of its way. Her eyes were dead, her skin bloodless. How cold she was. She might have been a corpse, if it had not been for her lips that twitched ceaselessly, repeating a silent mantra that might have been Emmeline, Emmeline, Emmeline.