I first met the lady when I was working late at the clinic. In truth I always work late at the clinic. Supplies are easy to get - comparatively easy - from our Western supporters, but staff are a different matter. And the local staff we train have homes and families to go to. It might as well be me. Her eyes were tired and wild and grief-stricken all at the same time. Her face was covered that night with an orange scarf in imitation of the niqab worn by some of my patients, but the cut of her shirt and leather pants told me she was not a Muslim.

She looked around with a powerful gaze, seeming to take in everything at a glance. "Can I help you?" I asked. I realised I had spoken in English - I was tired - but before I could switch to one of the local dialects, or French which everyone seems to think the doctors should speak, she answered, "I need... blood." The request was so strange and so desperate it stuck in my mind, but she pulled herself together and began again, "I'm a nurse at a private clinic in the city. The hospital blood isn't safe, and I need to arrange a transfusion."
"This is a charity, " I protested, "People who can pay go elsewhere. We don't just..." She handed me a roll of currency that would feed our whole caseload - and the staff - for a week. "What type do you need?" I asked weakly, fool that I was.
"O negative."

I went to our store, leaving her alone in my office. I was so confused I didn't even think about theft or confidentiality - anyone with that much money to throw at me didn't need to steal my simple supplies, but I should have thought about our client files. There were two bags of the right type that would soon go out of date. I handed them over and she left the clinic.

I tried to forget what I had done. I made no effort to hide the disappearance of two bags of O negative blood from the stores list, but no one noticed. The only person who paid any attention, I discovered, was me. I spent all the money on food for our patients, and a week later we were struggling again. What can I say? We were always struggling. When she reappeared, I was easily tempted. That time she had a name tag which read 'Dr Krempe', though she is no more German than I am. And she is no more a doctor than a nurse. She held out a wad of money that would pay our local staff's wages and I barely hesitated.

The third time it was a young man who came. Apart from the labcoat, his clothes were dark and his was face uncovered, though he wore heavy sunglasses in the early evening. 'Dr Polidori'* said his name tag, but I'm not that stupid. I equivocated then, "It will have to be destroyed tomorrow." He answered me harshly,
"We'll use it tonight," and again gave me enough money to buy antiretrovirals for all our HIV positive patients.

When did I begin to suspect? What form did my suspicions take?

I did investigate the other health care providers in the area, but I found nothing. I don't even know what I expected to find. The fourth or fifth time they came to me, I realised the woman's eyes were a different colour - more peaceful blue than lupine brown. I asked one night - it is always at night, as if the paleness of their skin cannot stand the sunlight - if she sourced blood for her patients from elsewhere? We maintain the fiction of her patients, just as we maintain the fiction of me asking for blood type. She answered, "You can't trust the hospital here, too much contamination. No, only from you." There is money for medicines, there is money for training and employing local staff, there is money for outreach into the surrounding areas, for antenatal health promotion, to provide safe water for drinking and washing. We couldn't continue, now, without the untraceable influxes of cash.

'Dr Polidori' came again tonight. I had not yet closed the clinic, and in my scalpel blade and the stainless steel trolley he cast no reflection. He said nothing and behind his dark glasses, I couldn't tell if he noticed the direction of my gaze.

They take the blood that will go out of date - or is out of date. They fund the saving of so many lives. In taking from me they do not endanger others. How far can you extend, "First you shall do no harm"?

I heard the other day that the doctor who ran this clinic before me died of a massive stroke just days after arriving home in France. Too much stress out here, apparently. I'm afraid I've ended up on his road - the one paved with good intentions.

*Author and personal physician to a certain "pompous ass". When Dr Watson didn't toss this name at Adam, it was the genesis of this story.