My twenty-two-year-old frame was hung with grey flannel 'bags' and a brown Harris tweed jacket, a long knitted blue-red-and-gold Trinity College scarf tucked into the lapels. My fair hair was disarrayed. I was red-nosed and raw-handed. One fist carried a brown cardboard attachй case from Woolworth's, which contained principally rye bread and sliced sausage for my lunch, the other clasped a flapping umbrella. God knows why I perpetrated the image of a typical Cambridge undergraduate going about his business in an obscure Rhineland industrial town. Perhaps it was patriotic bravado, or insularity, or 'bohemianism'. Or perhaps I couldn't afford a change of clothes.

'I have an appointment this morning to see Professor Dr Domagk,' I replied in German.

'I'm sorry, mein Herr, but it is strictly forbidden to enter the laboratories.'

My English accent made her more agitated, and I thought prettier. At that age I had a pressing interest in women. (Perhaps it persisted. I have had more wives than usually allowed a Professor of Biochemistry.)

_'Streng verboten,'_ she repeated, torn between duty and courtesy. In the Europe of those days, even neighbouring foreigners enjoyed the rarity and mystery of Turks to the Elizabethans. 'Please wait outside.'

This was strange. The Dunn Labs were as open to visitors as Cambridge railway station, and far more convenient than those famously remote platforms. I was about to comply when a door in the far corner opened to admit two men in white linen lab coats.

The first struck me as a younger copy of the Republic's President, Field-Marshal von Hindenburg. He was fiftyish, square-built, bull-necked, bushy eyebrowed, his hair iron grey, his moustache close-clipped, wearing circular horn-rimmed glasses (but everyone's glasses were circular then). The other's lab coat was too long in the sleeves, unbuttoned to display brown trousers badly in need of a press. I recognized him at once from my German host's description as Professor Gerhard Domagk.