George Barger (1878-1939), British chemist. Barger began his career in 1903 with work on the chemical structure and synthesis of the hormone adrenaline. He continued to work on biological chemicals, and analysed the fungus ergot, the chemical histamine (involved in allergic reactions) and noradrenaline (a neurotransmitter). In 1927, Barger determined the structure of a thyroid hormone, thyroxine, and then succeeded in synthesizing it (making in the laboratory). He was also involved with determining the structure and method of synthesis for thiamine (vitamin B1).