In 1883, Benjamin Ward Richardson, a distinguished doctor, denounced the evils of a drug. He said it caused an "extremely nervous, semi-hysterical condition". He was talking about tea. In 1936, the American Journal of Nursing claimed that a marijuana taker "will suddenly turn with murderous violence upon whomever is nearest to him". It seems clear that the author had finished a heavy tea-drinking session just before writing this. It is time to discard the old images and out-dated propaganda.

John Bonham-Carter

Manager, Biotech company, London