The pharmacy enters a period of new inventions and new laws. In 1868 pharmacies were regulated by law for the very first time - and Ruth, Tom and Nick face a taste of the tough examinations pharmacists went through to become qualified.They also explore the world of poisons and hazards that were completely unregulated until this time - from arsenic and opium to explosives. But the lack of restrictions they had enjoyed enabled 'experimental chemists' to invent products ranging from matches to fireworks, to custard and jelly. The team learn the processes involved in each, and lay on a Victorian style firework display for their customers.