It's often very difficult to lead a horse across a bridge for the first time. One of the methods that may be used is to place a blindfold over the horse's eyes, so it cannot see the imagined terror. Even then though, the animal will not walk forwards unless it trusts its handler beyond a shadow of a doubt. This can be a very telling test.

House could move quickly sometimes for a cripple. Chase's world went very suddenly black, before he even had a chance to protest. 'House!' he exclaimed, reaching up a hand to claw away the blindfold.

'Ah ah. Leave it there. We're doing an experiment.' His voice stopped the movement in mid-air, and Chase instead folded his hands across his chest, leaning back in his chair and attempting to show his thorough disapproval for this. It wasn't helpful that he couldn't see a thing.

'Is this really necessary?' he sighed.

'We all have to make sacrifices sometimes,' House told him sanctimoniously.

'Great. Why isn't Foreman wearing the blindfold then?'

'Because you're cuter. Can you see?' There was a quiet sound of amusement from Foreman. Chase dug his fingernails into his palm.

'Strangely enough, there's a blindfold over my eyes.'

'Good.'

Cameron and Foreman watched the show with mixed feelings of interest and amusement. Chase lounged in his chair, dignified and relaxed, head held high despite the black material that covered his eyes, knotted behind his head with the ends hanging down his back. House paced around behind him, slight triumph on his face. He did so love his dramatic demonstrations.

'Now, unless you've been really inept in your examination, it would seem that our patient is blind.'

'That's not related to his condition though,' Cameron frowned. 'He was born blind. He's sixty.'

'Sixty-three. And how sure are you of your other facts?'

'Huh?' Foreman questioned dubiously, sceptically eyeing House. House silently held up a whiteboard marker between two fingers. Stopping behind Chase, he grabbed a wrist, unpeeling the arm from across his chest. Chase didn't resist- although he'd jumped on the contact- allowing his other arm to drop into his lap. With his hand wrapped around Chase's wrist, House could feel the thundering heart beat, and realised with slight wonder that it was actually upsetting Chase quite a lot to not be able to see. Bemused by the clenched fist that matched the pulse, House unpeeled that too, silently noting the white marks where nails had bitten into the skin before placing the marker into the hand and releasing it.

'What's that?' he asked.

Pursing his lips, Chase didn't even need to explore the object in his hand. 'It's one of your beloved markers,' he replied dryly, his hand still held out to one side, open where House had left it.

'Never touched it before?'

'That's why I said 'beloved.' You won't let us touch them, remember?'

'What's your point House?' Foreman asked, although he was enjoying watching Chase in a blindfold.

'Either our patient has been in hospital before, or he's seen hospitals on TV.'

'He's been blind since birth,' Cameron reminded him again.

'Has he? Chase has only ever seen the markers, but he knows what they feel like.'

'I can also smell the ink from here,' Chase pointed out. 'Can I take this off now?'

'No,' House denied him offhandedly, before explaining to Cameron and Foreman. 'Inter-sensory adaptation means we can work out what something feels like from what it looks like, or what it tastes like from what it smells like. Simon Dolshev should never have felt the vast majority of things in the hospital, but he knew what some of them were- like the stat monitor and the blood pressure cuff.'

'He could have heard them described.'

'Unlikely.'

'And why do you think that means he used to be able to see anyway?' cut in Foreman. 'He may just have been in hospital before. We've only got his medical records from after when he emigrated.'

'Exactly. Meaning we don't know what it was that caused the blindness.'

'He told us what it was that caused the blindness. And why would he lie about that?'

Chase was turning his head back and forth slightly as each of them spoke, simultaneously trying to follow House's movements, since he paced as he talked. 'Maybe it's shameful in Russia to have acquired blindness,' he offered sarcastically. House raised his eyebrows in amusement at the blindfolded man. Chase shifted slightly in the silence, closing his fist on the marker and placing it on the table.

'For starters, him telling us that he's been blind since birth doesn't actually tell us what caused the blindness. Secondly, people will lie even when there is no apparent point in lying.' As he spoke, House fetched a pen and pad of paper off the side bench, returning to stand behind Chase, who tried not to flinch away from the proximity.

'Skittish are we?' he asked in amusement. Chase just frowned, not answering.

'Is there any point in this?' he sniped, uncomfortable.

'There is if we want to cure the real blind man.' House placed the pad of paper down on the table in front of Chase and tugged lightly at the marker in his hand until he let it go, replacing it with the pen. Chase shifted the implement in his grip until he was holding it ready to write.

'Point number one. You've all observed our patient do the same.'

'Do what?' asked Cameron.

'Shift a pen into a writing hold. When does a blind man, growing up in rural Russia, learn to write?'

'It doesn't mean he knows how to write,' Foreman dismissed it.

'Yeah. Right. Chase, sign your name.'

'I need paper.'

'It's in front of you.'

Chase obligingly felt for the paper with his left hand, briefly running fingers over it before putting the pen down and scribbling rapidly. House held up the paper when he was done. 'Exhibit B.'

'It's his signature,' stated Foreman dryly.

'Well done. And what does it tell you?' House demanded irritably.

'That he's a doctor,' offered Cameron. That got a small laugh out of the blindfolded Chase.

'And?'

'Uh… he knows how to sign his name?'

'Obviously. Keep going.'

There was silence, and House sighed, limping quickly into his office, fetching another piece of paper, and returning. It was a consent form for diagnostic tests from their patient. He held it up next to Chase's signature. 'You depress me sometimes. Notice the letters.'

'It… isn't just an X?' tried Foreman.

'Thankyou,' expelled House.

'Uh…' started Cameron, still not sure what this meant. Foreman was equally ignorant. House tapped his cane twice on the floor in impatience. 'Our patient knows how to write.'

'Maybe his parents taught him.'

'To what end? And how? Observational learning was obviously out.'

'Can I take the blindfold off now?'

'No.'

'So he hasn't been blind since birth,' Foreman filled in.

'You think his blindness was caused by something that's playing with his heart now?' Cameron questioned, considering it herself. House nodded, taking the marker from off the table next to Chase (eliciting another flinch), and using it to write up 'blindness' on the board.

'What was that?' asked Chase, hearing the squeaking of the marker.

'He wrote 'blindness',' Cameron said for him.

'We could go and ask him again why he's blind,' Chase pointed out.

'No. If he's lied once, he'll probably just change his story a little. And we'll still have no idea if it's the real one… So, what causes blindness?'

'Adult chickenpox.'

'He was twelve when he came here. Any chickenpox would have been in his medical records. And he was blind before he came.' Cameron rebuffed Foreman's idea before suggesting one of her own. 'It could have been some sort of trauma, to his eyes or the back of his head.'

'Has anyone actually examined his eyes?' interjected Chase.

'Hmm. Good question Dr. Chase,' House said, looking meaningfully at Cameron and Foreman.

'If it's a neurological problem, there's very little we'll see wrong with the eyes themselves,' Foreman pointed out.

'And if its not, it might tell us that we were wrong for dismissing prior damage to the heart. Any sort of virus that took out his retinas could have similarly damaged his heart muscle, making him susceptible to whatever is hitting him now.'

'We'll go look,' Cameron told him, rising. Foreman followed her action, weaving past the chairs around the table, towards the door. Chase clenched his teeth, realising that House wasn't going to release him yet. The sounds of the other two faded abruptly as the door swung shut behind them, abandoning him to House's questionable mercy.

TBC