'So Laveran puts two and two together: hey, this thing moves, it's a bug. He faxes the Academy of Medicine in Paris; tells them he's found the cause of malaria and it's a critter, a protozoan – an animal parasite. But Paris doesn't buy it. Pasteur's the boss out there and he's sent the smart money chasing after bacteria. No one buys Laveran's protozoan critter: it's like he said he found the yeti. Some of the biggest names in medicine get busy refuting "Laveranity". The only converts are the Italians: they become born-again Laveranites. In 1886 Camillo Golgi shows that Laveran's parasite grows inside the red blood cell, eating its host and shitting black pigment; that the pigment collects in the centre while the bug begins to divide; he demonstrates that the recurrence of malarial fevers is linked to this pattern of asexual reproduction.

'Ronnie's a wallflower while this party's heating up. He's on the anti-Laveran bench. He thinks Laveran's bug doesn't exist: he's spent the last several months trying to catch a glimpse of it and hasn't succeeded. He's even published an article trying to prove that Laveran was hallucinating. The first time Ronnie ever sees the bug is in Manson's lab. He converts, and Manson sends him hustling back to India to look for the vector.'

Antar broke in: 'So it was Manson who was responsible for conceiving of the connection between malaria and mosquitoes?'

'It wasn't exactly a new idea,' said Murugan. 'Most cultures that had to deal with malaria knew there was some connection. '

'But,' Antar persisted, 'you're saying it's Manson who first gave Ross the idea?'

'You could say Manson pointed in the general direction,' said Murugan. 'Except that he sent him down the scenic route. He had this screwball theory that the malaria bug was transmitted from mosquito to man via drinking water. His plan was to get Ronnie to do the grunt work on this theory of his.'

'And Ross believed in this theory?'

'You bet.'

'So what happened?' said Antar.

'OK, we're back in 1895, right? Ross can't wait to get started on Doc Manson's mosquito-juice theory. He gets off the ship at Madras and takes a train up to join his regiment, the 19th Madras Infantry. They're stationed in a neighbourhood called Begumpett in Secunderabad. On his way up Ronnie sticks needles into anything that moves. When he pulls into Begumpett he begins to offer money for samples of malarial blood – real money, one rupee per prick! Think about it. This is 1895; one rupee can buy a family of four enough rice to last a month. There's so much malaria in this place, the mosquitoes are doing double shifts and can't keep up. And here's Ronnie willing to pay real money for a few drops of malarial blood, and he can't find a single taker. Someone's put out the word that this weird doctor's blown into town and he gets his rocks off putting naked guys into bed with mosquitoes. No one's going near him; they're crossing the street to get away. Suddenly Ronnie finds himself starring in a bad-breath commercial: every time he steps out on Main Street, Begumpett, it's empty.

'Then suddenly his luck changes. On May 17 1895, just when it begins to look really hopeless, he gets his first perfect case of malaria – a patient called Abdul Kadir. Ronnie goes into high gear: he strips Abdul Kadir, shoves him into a bed, drapes a wet mosquito net over him and releases a test-tube full of mosquitoes into it. Next morning he harvests his crop and suddenly Ronnie's laboratory is the happening place in Begumpett. Until then he's observed only two of the flagellate forms of the parasite. On May 18 he flattens one of Abdul Kadir's mosquitoes (mosquito number 18) and he finds sixty parasites in a single field. He's so excited he does back-flips all the way to his desk. He's found a "wonder case" he writes Doc Manson. That's just the beginning. The first time Ronnie sees the crescentsphere transformation of the parasite is on June 26 1895, in Abdul Kadir's blood. Over the next couple of months Abdul Kadir's blood guides him through all the critical phases of his research.'

'Can a single case make that much difference?' said Antar.

'Ronnie thought so,' said Murugan. 'He was convinced that Abdul Kadir was crucial to his work. He'd looked at a fair number of blood samples already but none of them ever showed him what Abdul Kadir's did. You'd think a bug like the malaria parasite wouldn't look for any teacher's pets, but maybe it doesn't work that way. Maybe it shows itself more clearly in certain cases. That's what Ronnie thought, anyway. He became hooked on Abdul Kadir and his blood. Days when Abdul Kadir's parasites went into remission Ronnie was climbing the walls. "Alas! the wonder case which fortune has sent me is drying up", he wrote Doc Manson on May 22. The dickhead had an ego so big he thought Fortune was putting him on its cover. He clearly knew that Abdul Kadir was a special case. But he never stopped to ask himself how come this guy just walked through the door when he needed him most. He thought it was just luck.'

'Let me be clear about this,' said Antar. 'Are you suggesting that Abdul Kadir's arrival at the hospital on May 17 wasn't just coincidence?'

'You've got to wonder,' said Murugan. 'Look at it this way: Ross knows no one else will come near him even when he doubles or triples his one-rupee per prick rate; on July 17 he writes Doc Manson: "The bazaar people won't come to me even though I offer what is enormous payment to them. I offer two and three rupees for a single finger prick and much more if I find crescents – they think it is witchcraft." But Ronnie never stops to ask himself: why's this guy Abdul Kadir here, if no one else is? How come he doesn't think this is witchcraft? What makes him so special? Where's he from? What's he doing here? What's his story? We're not talking deep therapy: just plain, everyday curiosity. But Ronnie keeps all his curiosity for the life cycle of the malaria parasite; about the life cycles of its hosts he couldn't care less.'

'So what are you suggesting?' Antar said sharply.

'I'm not suggesting anything at this point,' said Murugan. 'I'm just giving you the facts and the chronology.'

'All right,' said Antar. 'Go ahead.'

'OK,' said Murugan. 'We fast forward to the week after Abdul Kadir's arrival: May 25 1895. Doc Manson thinks Ronnie's getting sidetracked, so he's written to remind him of his theory: that "the beast in the mosquito… gets to man in mosquito dust". He wants Ronnie to make a cocktail from dead mosquitoes and feed it to someone.

'Ronnie gets out his glasses and starts mixing. Trouble is, he hasn't got anyone to give it to: can't find anyone fool enough to volunteer. Same old story: Ronnie's in his lab in Begumpett, all dressed up and nowhere to go.

'And what do you know? Ronnie gets lucky once again. Or maybe it's not just luck; maybe he left Doc Manson's letter out on his desk and someone read it. Maybe. Anyway, on May 25 1895, at exactly 8 p.m., a guy called Lutchman walks into Ronnie's life. He volunteers to drink Ronnie's cocktail. Ronnie pops the corks and breaks out the mosquito margarita.

'This Lutchman's a "healthy looking young fellow" Ronnie notices: just the guinea pig he's been looking for. He explains the experiment to Lutchman and hands him the dead-mosquito concoction. Lutchman makes like he doesn't already know what it is, and swigs it. Ronnie's a little anxious but he doesn't let on. All he knows about Lutchman is that he's a "dhooley-bearer": in other words the British government pays him to shovel shit. Ronnie knows Her Imperial Majesty wouldn't be too pleased about this little experiment of his if she got to hear of it up in her castle on London Bridge or wherever. Later he covers his tracks by writing Doc Manson: "Don't for heaven's sake mention Lutchman at the British Medical Association… he is a government servant. To give a government servant fever would be a crime!"