THERE WERE TIMES, AND they came frequently enough, when one could believe that modern society, machine-age America, was addicted to poisons. Every day retold the story of that dependency: poisons floated in the exhaust-smudged air of the morning commute and swam in the evening martini, in the gas-fed blue flames of the stove, in the soft smoke of the after-dinner cigarette, in the barbiturates that so many now swallowed at the end of a stressful day.