SIR-America's criminalisation of marijuana began in the 1930s when
DuPont's chemists developed petrochemical cellophane and nylon while
perfecting the sulphate-sulphite process to make cheap paper from wood
pulp. William Randolph Hearst was then busy investing millions in
timber in both America and Mexico. The only competition came from
hemp, a crop requiring scant water and no pesticides. Newspaper pulp
manufactured from hemp required no toxic sulphites and offered more
pulp per acre than trees.

It was also a cheap base for commercial plastics.

The two industrial giants conspired and eventually wiped out
America's commercial hemp. Hearst geared up his newspaper empire to
criminalise hemp while DuPont's lobbying in Washington helped
establish the Federal Bureau of Narcotics in 1930. The then secretary
of the treasury, Andrew Mellon, was also DuPont's lawyer.

In August 1937 President Roosevelt dealt commercial hemp a fatal blow
by signing the Marijuana Tax Act.

EDWARD MILLER
San Rafael, California