Prothoracicotropic hormone
Prothoracicotropic hormone (PTTH) was the first insect hormone to be discovered. It was originally described simply as "brain hormone" by early workers such as Stefan Kopeć (1922) and Vincent Wigglesworth (1934), who realized that ligation of the head of immature insects could prevent molting or pupation of the body region excluded from the head if the ligation was performed before a critical age in the lifestage was reached. After a certain point the ligation had no effect and both sections of the insect would molt or pupate. However, implantation of a conspecific brain to a sessile ligated abdomen or an abdomen under diapause would induce molting or pupation. Thus, the brain was originally thought to be the source of the hormone that induces molting in insects.
Morphine
Morphine was discovered as the first active alkaloid extracted from the opium poppy plant in December 1804 in Paderborn, Germany, by Friedrich Sertürner. In 1817 Sertürner reported experiments in which he administered morphine to himself, three young boys, three dogs, and a mouse; all four people almost died. Sertürner originally named the substance "morphium" after the Greek god of dreams, Morpheus, as it has a tendency to cause sleep. Sertürner's morphium was six times stronger than opium. He hypothesized that, because lower doses of the drug were needed, it would be less addictive. However Sertürner became addicted to the drug, warning that "I consider it my duty to attract attention to the terrible effects of this new substance I called morphium in order that calamity may be averted."