I have soaked 1 or 2 cups of poppy seeds in lemon juice for about an hour; the acidic juice eats through the skin of the seed and releases the opium. I then strained the juice into a cup, added cold water and heaps of honey, and ice. I can attest the resulting drink is more potent than many of the prescription pill opiates. My flatmate was studying to be a pharmacologist so I felt comfortable with his assurance that I wouldn’t die, but I could see it becoming as addictive as anything else. So yes, you can get a dose from just seeds. Carefully.
Chaucer's tale exposed the more fraudulent side of alchemy, especially the manufacture of counterfeit gold from cheap substances. Less than a century earlier, Dante Alighieri also demonstrated an awareness of this fraudulence, causing him to consign all alchemists to the Inferno in his writings. Soon after, in 1317, the Avignon Pope John XXII ordered all alchemists to leave France for making counterfeit money. A law was passed in England in 1403 which made the "multiplication of metals" punishable by death. Despite these and other apparently extreme measures, alchemy did not die. Royalty and privileged classes still sought to discover the philosopher's stone and the elixir of life for themselves.