Sir

The article on Emil Abderhalden and his fraudulent “defence enzymes” (Nature 393, 109–111; 1998) brought back memories. When I was a graduate student at Columbia University in 1950, engaged in developing methods of peptide synthesis, I found that almost invariably I could not repeat Abderhalden's experiments.

In one of my most frustrated moods, I asked my mentor, Dr Erwin Brand, if Abderhalden was always wrong. “No,” he said. “He is not that reliable”.