I was directed across a triangular yard cut by railway tracks, where a gang of workmen in leather aprons and shiny-peaked caps were loading a dray with carboys of chemicals in straw nests, every man's breath a cloud, the four horses pawing the icy cobbles and smoking like dragons. As I crossed the river by a footbridge of railway sleepers I caught the familiar smell of phenol. All Wuppertal stank. Any town making its living from chemicals in those days suffered its nose to be corroded. The factory was the pharmaceutical division of I G Farben, the works strung along the river in the 1880s by the old Bayer drug company, which still gave its name to the medicaments. From phenol, the Germans were making aspirin to soothe the headaches of the world.

The six-storey research block was modern, a cleanly contrast to the industrial jungle. I was making for the pathology department on the fourth floor, where I found a door to the left of the short corridor ajar, and walked in. I discovered myself in an amazingly luxurious laboratory. It was light and airy on the corner of the building, with white-tiled walls, white desks and swivel chairs, a telephone, even a refrigerator. The bench was separated from a huge window by a shelf of plants in pots, the elaborate microscope was far beyond the pocket of the Sir William Dunn Laboratories at Cambridge, which I had just quit. Its only occupant was a girl in a white coat, busy over conical flasks with cotton-wool stoppers. She was pretty, round faced and dark-haired, her eyes murmuring a hint of the Slav.

'Yes? What do you want?' she asked sharply.

I must have appeared a freak. At Cambridge I had learned, like Michael Arlen's Gerald, to despise the genteel habit of wearing an overcoat, whether it blew, rained, snowed or froze.