Who discovered penicillin? Fleming or Florey? Would either have seen its possibilities, had not the sulpha drugs come from Nazi Germany? And who was the sulpha drugs' begetter? Gerhard Domagk, awarded the Nobel Prize? Or an unknown German professor, at the same time on trial for his life at Nьrnberg for complicity with Hitler's SS?

My research in London, Oxford and Wuppertal gave fresh knowledge about the discoverers of these drugs, which have benefited almost everyone alive today. This is a novel, but its historical and medical facts stay close to the truth. The scientists Colebrook, Wright, Hopkins, Freeman, Raistrick and Hцrlein all lived. Chain, Fletcher and Heatley happily still do.

A note about microbes. The sulpha drugs and penicillin kill the dangerous germ streptococcus in the body. The equally deadly staphylococcus is killed by penicillin, but not by the sulpha drugs.

You could see the whole of Wuppertal from the Schwebebahn. That was the famous overhead railway, its green-painted girders bestriding ten miles of the River Wupper like an angular centipede. Its neat red-and-white aerial tramcars, suspended from their monorail, gave the entrancing feeling of floating in the gondola of a low-flying Zeppelin. The first ride had been taken on October 24, 1900 by Kaiser Wilhelm II, wearing his field-grey military cape and spiked helmet. The only accident in its history, as everyone in Wuppertal told you sooner or later, was a baby elephant involved in a circus stunt falling through the floor into the water.

Wuppertal was a snake of a town, twisting along a steep wooded valley in places barely quarter of a mile across, lined with narrow slate-roofed tenement houses rising on each other's shoulders.