I said, ‘We wouldn’t worry so much if that was all, but just consider. You can be immunized from the effects of penicillin. At the best you can say that the use of this stuff makes a penicillin treatment for the particular patient ineffective in the future. That isn’t so funny, of course, if you are suffering from V.D. Then the use of sand on a wound that requires penicillin – well, it’s not healthy. Men have lost their legs and arms that way – and their lives. But perhaps what horrified me most was visiting the children’s hospital here. They had bought some of this penicillin for use against meningitis. A number of children simply died, and a number went off their heads. You can see them now in the mental ward.’

He sat on the other side of the desk, scowling into his hands. I said, ‘It doesn’t bear thinking about very closely, does it?’

‘You haven’t showed me any evidence yet that Harry –’

‘We are coming to that now,’ I said. ‘Just sit still and listen.’ I opened Lime’s file and began to read. At the beginning the evidence was purely circumstantial, and Martins fidgeted. So much consisted of coincidence – reports from agents that Lime had been at a certain place at a certain time; the accumulation of opportunities; his acquaintance with certain people. He protested once, ‘But the same evidence would apply against me – now.’

‘Just wait,’ I said. For some reason Harry Lime had grown careless: he may have realized that we suspected him and got rattled. He held a quite distinguished position in the Relief Organization, and a man like that is the more easily rattled. We put one of our agents as an orderly in the British Military Hospital: we knew by this time the name of our go-between, but we had never succeeded in getting the line right back to the source. Anyway, I am not going to bother the reader now, as I bothered Martins then, with all the stages – the long tussle to win the confidence of the go-between, a man called Harbin. At last we had the screws on Harbin, and we twisted them until he squealed. This kind of police work is very similar to secret service work: you look for a double agent whom you can really control, and Harbin was the man for us. But even he only led us as far as Kurtz.

‘Kurtz!’ Martins exclaimed. ‘But why haven’t you pulled him in?’

‘Zero hour is almost here,’ I said.

Kurtz was a great step forward, for Kurtz was in direct communication with Lime – he had a small outside job in connection with international relief. With Kurtz, Lime sometimes put things on paper – if he was pressed. I showed Martins the photostat of a note. ‘Can you identify that?’

‘It’s Harry’s hand.’ He read it through. ‘I don’t see anything wrong.’