'What? Everyone likes some comfy cushions when they're feeling a little under the weather, don't they?' said the man to whom sickness was a mystery.

'He was a table this morning. Mahogany, I believe. He seems to be able to retain his colour, at least.'

The Lecturer in Recent Runes closed the book with a sigh. 'He's certainly lost control of his morphic function,' he said. 'It's not surprising, I suppose. Once it's been changed, it'll change again much more easily, I'm afraid. A well known fact.'

He looked at the Archchancellor's frozen grin and sighed. Mustrum Ridcully was notorious for not trying to understand things if there was anyone around to do it for him.

'It's quite hard to change the shape of a living thing but once it's been done it's a lot easier to do it next time,' he translated.

'Say again?'

'He was a human before he was an ape, Archchancellor. Remember?'

'Oh. Yes,' said Ridcully. Tunny, really, the way you get used to things. Apes and humans are related, accordin' to young Ponder here.'

The other wizards looked blank. Ponder screwed up his face.

'He's been showing me some of the invisible writings,' said Ridcully. Tascinatin' stuff.'

The other wizards scowled at Ponder Stibbons, as you would at a man who'd been caught smoking in a firework factory. So now they knew who to blame. As usual...

'Is that entirely wise, sir?' said the Dean.

'Well, I do happen to be the Archchancellor in these parts, Dean,' said Ridcully calmly.

'A blindly obvious fact, Archchancellor,' said the Dean. You could have cut cheese with his tone.

'Must take an interest. Morale, you know,' said Ridcully. 'My door is always open. I see myself as a member of the team.' Ponder winced again.

'I don't think I'm related to any apes,' said the Senior Wrangler thoughtfully. 'I mean, I'd know, wouldn't I? I'd get invited to their weddings and so on. My parents would have said something like, "Don't worry about Uncle Charlie, he's supposed to smell like that," wouldn't they? And there'd be portraits in—'

The chair sneezed. There was an unpleasant moment of morphic uncertainty, and then the Librarian was sprawling in his old shape again. The wizards watched him carefully to see what'd happen next.

It was hard to remember the time when the Librarian had been a human being. Certainly no one could remember what he'd looked like, or even what his name had been.

A magical explosion, always a possibility in somewhere like the Library where so many unstable books of magic are pressed dangerously together, had introduced him to unexpected apehood years before. Since then he'd never looked back, and often hadn't looked down either. His big hairy shape, swinging by one arm from a top shelf while he rearranged books with his feet, had become a popular one among the whole University body; his devotion to duty had been an example to everyone.

Archchancellor Ridcully, into whose head that last sentence had treacherously arranged itself, realized that he was unconsciously drafting an obituary.

'Anyone called in a doctor?' he said.

'We got Doughnut Jimmy here this afternoon,' said the Dean. 'He tried to take his temperature but I'm afraid the Librarian bit him.'

'He bit him? With a thermometer in his mouth?'

'Ah. Not exactly. There, in fact, you have rather discovered the reason for his biting.'

There was a moment of solemn silence. The Senior Wrangler picked up a limp black-leather paw and patted it vaguely.

'Does that book say if monkeys have pulses?' he said. 'Is his nose supposed to be cold, or what?'

There was a little sound, such as might be made by half a dozen people all sharply drawing in their breath at once. The other wizards began to edge away from their Senior Wrangler.

There was, for a few seconds, no other sound but the crackling of the fire and the howl of the wind outside.

The wizards shuffled back.

The Senior Wrangler, in the astonished tones of someone still possessing all known limbs, very slowly took off his pointy hat. This was something a wizard would normally do only in the most sombre of circumstances.

Well, that's it, then,' he said. 'Poor chap's on his way home. Back to the big desert in the sky.'

'Er. rainforest, possibly,' said Ponder Stibbons.

'Maybe Mrs Whitlow could make him some hot nourishing soup?' said the Lecturer in Recent Runes.

Archchancellor Ridcully thought about the housekeeper's hot nourishing soup. 'Kill or cure, I suppose,' he murmured. He patted the Librarian carefully. 'Buck up, old chap,' he said. 'Soon have you back on your feet and continuing to make a valued contribution.'

'Knuckles,' said the Dean helpfully.

'Say again?'

'Knuckles, rather than feet.'

'Castors,' said the Lecturer in Recent Runes.

'Bad taste, that man,' said the Archchancellor.

They wandered out of the room. From the corridor came their retreating voices:

'Looked very pale around the antimacassar, I thought.'

'Surely there's some sort of a cure?'

'The old place won't be the same without him.'

'Definitely one of a kind.'

When they'd gone the Librarian reached up cautiously, pulled a piece of blanket over his head, cuddled his hot-water bottle and sneezed.

Now there were two hot-water bottles, one of them a lot bigger than the other and with a teddy bear cover in red fur.

Light travels slowly on the Disc and is slightly heavy, with a tendency to pile up against high mountain ranges. Research wizards have speculated that there is another, much speedier type of light which allows the slower light to be seen, but since this moves too fast to see they have been unable to find a use for it.

This does mean that, despite the Disc being flat, everywhere does not experience the same time at, (or want of a better term, the same time. When it was so late at night in Ankh-Morpork that it was early in the morning, elsewhere it was...

... but there were no hours here. There was dawn and dusk, morning and afternoon, and presumably there was midnight and midday, but mainly there was heat. And redness. Something as artificial and human as an hour wouldn't last five minutes here. It would be dried out and shrivelled up in seconds.

Above all, there was silence. It was not the chilly, bleak silence of endless space, but the burning organic silence you get when, across a thousand miles of shimmering red horizons, everything is too tired to make a sound.

But, as the ear of observation panned across the desert, it picked up something like a chant, a reedy little litany that beat against the all-embracing silence like a fly bumping against the windowpane of the universe.

The rather breathless chanter was lost to view because he was standing in a hole dug in the red earth; occasionally some earth was thrown up on the heap behind him. A stained and battered pointy hat bobbed about in time with the tuneless tune. The word 'Wizzard' had, perhaps, once been embroidered on it in sequins. They had fallen off, but the word was still there in brighter red where the hat's original colour showed through. Several dozen small flies orbited it.

The words went something like this:

'Grubs! That's what we're going to eat! That's why they call it grub! And what're we doing to get the grub? Why, we're grubbing for it! Hooray!' Another shovelful of earth arced on to the heap, and the voice said, rather more quietly: 1 wonder if you can eat flies?'

They say the heat and the flies here can drive a man insane. But you don't have to believe that, and nor does that bright mauve elephant that just cycled past.

Strangely enough, the madman in the hole was the only person currently on the continent who might throw any kind of light on a small drama being enacted a thousand miles away and several metres below, where the opal miner known only to his mates as Strewth was about to make the most valuable yet dangerous discovery of his career.