'The vitamins may be a simple idea,' he said, turning Hoppy's few pages, 'but simple ideas need genius to see them. I have often to remind myself that a scientist must view the world through a telescope as well as a microscope. Though sometimes even a telescope is unnecessary, because the most useful ideas stand on the horizon like mountains and we never see them.'

There was a silence. The conversational possibilities between us seemed swiftly exhausted. Perhaps thinking it churlish to evict me so promptly, Domagk added, 'I understand from Dr Dieffenbach that you're working for the Red Crown brewery across at Barmen. That's the American concern, isn't it? Do you find the job interesting?'

'Not in the slightest.'

Domagk gave his shy smile, tossing the spent match into a large glass ashtray. 'Well, I prefer wine myself. And so does Dr Dieffenbach.' I had already found the cellar no disadvantage in my lodgings. 'We don't see many Englishmen or Americans in Germany. It's understandable. The war was hardly a tennis match. You were lucky to go through it as a child, Herr Elgar. I had to leave Kiel University after my first semester to join the colours as a grenadier. I celebrated my nineteenth birthday in a dugout on the Belgian coast at Nieuport, fighting the Tommies. The Tommies wounded me in 1915, so I was posted to the Medical Corps.' He imparted all this with his usual quiet voice. 'In a most lowly capacity. The upshot was my qualifying in medicine at Kiel five years later than I expected. Well, I shouldn't complain. Most of my academic brothers lost their lives.'

I felt somehow personally responsible for these misfortunes, and for some reason quoted H G Wells, 'It was the war that will end war.' But Domagk only smiled again and diverted the unpleasant subject by asking, 'Have you done any research yourself?'

I nodded. 'I held a six months scholarship at Cambridge after taking Tripos. I studied the affinity of bacteria for dyes.'