The assistant, who had gone over to fetch a tray of slides, was whispering with the woman in the sari. It was soon clear that it was him, Farley, they were talking about: the distorted reflections of their faces seemed to take on a grotesque and frightening quality as they nodded and pointed across the room. Farley quickly lowered his head to the microscope, while watching the glass out of the corner of his eye.

What he saw next was even more startling than what had passed before. At the end of the whispered conversation it was not the young assistant but the woman who went over to the stack of drawers by the wall; it was she who selected the slides that were to be presented to him for examination. Watching carefully, Farley saw her picking them out with a speed that indicated she was not only thoroughly familiar with the slides but knew exactly what they contained. Farley could now barely restrain himself. His mind began to spill over with questions: how had a woman, and an illiterate one at that, acquired such expertise? And how had she succeeded in keeping it secret from Cunningham? And how was it that she, evidently untrained and unaware of any of the principles on which such knowledge rested, had come to exercise such authority over the assistant? The more he reflected on it, the more convinced he became that she was keeping something from him; that had she wished she could have shown him what he was looking for, Laveran's parasite; and that she had chosen to deny it to him because, for some unfathomable reason, she had judged him unworthy.

Farley would now gladly have walked away from this place, this so-called laboratory, whose all too familiar instruments seemed to be turned to purposes as perverse as they were inscrutable. Yet he knew that if he left now he would for ever afterwards be tormented by uncertainty and doubt. He had no option but to pursue his enquiry no matter where it led.

And so Farley willed himself to stay where he was, with his eye fixed upon the microscope, staring sightlessly at the meaningless slides that were placed in front of him by the young assistant. After a full half-hour had passed, he said to the young man: 'I have not seen any sign of the parasite today, but I have it on good authority that it does indeed exist. So I shall have a word with Cunningham-sahib, and with his permission, I shall return tomorrow to continue my researches.'

At this a look of utter consternation descended on the assistant's hitherto smiling face. Farley saw him shooting a glance at the unnamed woman, who was watching them keenly from the other end of the laboratory. Then he launched upon a string of stammering protests: it was unnecessary to return the next day; there was nothing to be seen, it was just a pure waste of time, and anyway Cunningham-sahib would be away; better return later, some other day… in a fortnight, or a month hence, perhaps there would be something to see then…

The vehemence of his protests were such as to confirm Farley's suspicions: the man could not have indicated more clearly that he, and his silent companion across the room, were keen to rid themselves of him; that his presence the next day would disrupt some previously conceived connivance, some event or events that they had already planned, counting on Cunningham's absence.

Perceiving that he now held the advantage, Farley brushed past the pleading assistant, saying: 'Nevertheless I shall return tomorrow.'

With that he went to find Cunningham.

The Englishman was in the next room, seated on a chaise longue, puffing dreamily on a long-handled pipe. When Farley asked for his permission to continue the next day, he blew out a plume of sweet-smelling smoke and cried: 'Why, certainly, my boy! If you are determined to persist in your quest for this phantom of Laveran's, do come back, as often as you like. I'll tell them to expect you.'

On the point of taking his leave, Farley hesitated. He looked quickly about, to make sure that they were alone, and then, approaching the seated Englishman, he dropped to his knees.

'If I may enquire, sir,' he whispered in Cunningham's ear, 'under what circumstances did you admit this woman into your laboratory?'

'Mangala?' said Cunningham, pointing his pipe-stem over his shoulder.

'If that is her name, yes.'

'If you're asking me how I found her,' Cunningham said, 'the answer is I found her where I find all my bearers and assistants: at the new railway station – what do they call it? – oh yes, Sealdah.'

'At the railway station, sir?' gasped the astonished Farley. 'Exactly so,' said Cunningham. 'That's the place to go if you need a willing worker: always said so – it's full of people looking for a job and a roof over their heads. See for yourself the next time you're there.'

'But, sir,' Farley exclaimed, 'to take on untrained and uneducated… '

'And who better to train one's assistants than oneself, my boy?' Cunningham countered. 'Far preferable, in my opinion, to being surrounded by over-eager and half-formed college students. One is spared the task of imparting much that is useless and unnecessary.'

'So it was you who trained the woman – Mangala?' Farley asked.

'Indeed I did,' said Cunningham, staring hazily into the middle distance. 'And a quicker pair of hands and eyes I had never seen before. But… '

Pulling a long face, Cunningham tapped his head with a finger. 'But she's not all there, you see,' he said, 'her mind's been wasted – by disease, or licentiousness or who knows what?'

'And the young man?' Farley asked. 'What about him?'

'He's not been here long,' Cunningham said. 'Mangala brought him here: said he was from her own part of the country.'

'And where is that?'

'Not far from where you are,' Cunningham said. 'I believe the place is called Renupur – you may have passed it on your way here.'

'Why, yes,' said Farley. 'I passed through Renupur on my way to Calcutta.'

Farley was just about to ask the assistant's name when he heard a sound behind him. He rose and found himself looking directly at the woman, Mangala. She was glaring at him from across the room, and such was the anger in her gaze that it sent a chill down his back. As he made his way out, he noticed that she was conducting a whispered consultation with the young assistant.

Farley had barely reached the bamboo thicket in front of the laboratory when he heard footsteps racing behind him. Moments later the assistant caught up with him and asked in a voice of polite, almost beseeching enquiry, exactly when it was that he planned to come the next day. Determined to retain the advantage of surprise, Farley gave him a noncommittal reply: 'I shall come when I find myself within the vicinity. My arrival need not interrupt your work for the day.'

With that he turned his back on the crestfallen assistant and walked away.

Through much of the night, for no reason that he could adduce, Farley prayed. Yet he could find no name for what it was that faced him and why he feared it. And this in turn became his very fear, that he could not name what he knew he must confront. All next morning he stayed in his room, touching neither food nor water, and did not emerge from his cubicle until the hour was well past noon.

Thus, once again, it was late afternoon by the time he arrived at the Hospital. But today, unlike the day before, the sky was grey and overcast, and a strong wind was blowing across the Maidan. Approaching the laboratory, Farley had the feeling that the stands of bamboo that separated it from the hospital were alive, astir with movement. And when he stepped into the thicket he saw that there were indeed shadows ahead of him, on the path: three figures, cloaked and swathed, stumbling slowly towards the laboratory. Farley stopped, overcome with misgiving, and then, collecting himself he went forward again. When he was but a few yards behind the figures, he saw that the little group consisted of a man in a dhoti and a sari-clad woman. They were bearing between them another, almost inert, human figure. He approached them boldly, rattling his fob to make his presence known.' They stopped and turned to face him.