EMERGENCE OF ORGANIC CHEMISTRY. “For them, “active principles” was not a reference to active matter, but to the particular molecule within a natural substance that was responsible for its action on the animal economy. In each case, chemists had worked out the chemical formula of these molecules – the amount of carbon, oxygen, and hydrogen that formed the truly foundational principles upon which everything was built. It was a triumph of the new field of organic chemistry.”
https://www.tandfonline.com/doi/full/10.1080/00026980.2020.1867786