Sir William Maddock Bayliss (1860–1924) was an English physiologist and Fellow of the Royal Society, renowned for his work with Ernest Starling. Bayliss gained a BSc from London University in 1881, but it was 4 years later at Wadham College in Oxford that he achieved his MA and DSc. In 1888, he took a teaching position at University College London which is where he would enter into research with Starling. Together, they discovered the peptide hormone secretin and peristalsis of the intestines. Secretin was the first hormone ever identified; Bayliss and Starling coined the term ‘hormone’ from the Greek phrase ‘I arouse/excite’. This breakthrough opened up new fields of medical and scientific research and discovery. Starling’s sister, Gertrude Ellen Starling married Bayliss in 1893: they went on to have four children together. In 1903, Bayliss successfully sued Stephen Coleridge for libel over the ‘Brown Dog Affair’ for claiming that Bayliss had not correctly sedated a brown dog on which he performed a vivisection, the same year in which he was elected a Fellow of the Royal Society. Bayliss went on to become the Professor of General Physiology at University College London in 1912, where he made discoveries into the effect of saline injections in countering shock experienced after surgery. In 1922, Bayliss was knighted for his contribution to medicine. On 27 August 1924, Sir William Maddock Bayliss died in London aged 64. The Physiological Society created the Bayliss Starling Prize Lecture as a joint memorial in 1960 and in 1979, the Bayliss and Starling Society was established, focusing on central and autonomic peptide functions.