Quests in this Chapter Type 1. The criminal must be mentioned early in the story. Event 2. All supernatural or preternatural agencies are ruled out as a matter of course. Event 3. No more than one secret room or passage is allowable. Event 4. No hitherto undiscovered poisons may be used. Event 5. No strange foreigners must figure in the story. Event 6. No accident nor unaccountable intuition must ever help the detective. Event 7. The detective must not himself commit the crime. Event 8. The detective is bound to detail any clues upon which he may light. Event 9. The Watson must not conceal his thoughts from the reader. Event 10. Twins and doubles must not appear unless we have been duly prepared for them. Event
