William Bayliss
| Category | Research |
|---|---|
| Also known as | William Maddock Bayliss, co-discoverer of secretin |
| Last updated | 2026-04-14 |
| Reading time | 3 min read |
| Tags | scientistsecretinhormonephysiology |
Overview
William Maddock Bayliss (May 2, 1860 – August 27, 1924) was a British physiologist whose partnership with Ernest Starling at University College London produced the first experimental demonstration of a hormone. Their 1902 discovery of secretin established that chemical messengers circulating in the blood — not only nerves — can coordinate physiological responses. This finding laid the empirical foundation for the field of endocrinology as a distinct discipline.
Bayliss's contributions extended well beyond secretin. His work on vasomotor control, on the enzymology of proteases, and on the physicochemistry of solutions and colloids was highly influential. During World War I, he championed the clinical use of saline solutions to treat shock, an intervention that saved countless lives and continues to inform modern fluid-resuscitation practice.
Bayliss also played a role in the legal defense of scientific research. In 1903, he successfully sued an anti-vivisection activist for libel in the famous "Brown Dog affair," a case that had long-lasting implications for animal research regulation in Britain.
Background
Bayliss was born in Butcroft, Wednesbury, in the West Midlands, and studied at University College London and Wadham College, Oxford. He spent nearly his entire career at UCL, where he became Professor of General Physiology in 1912. His laboratory was known as much for its methodological rigor as for the breadth of its topics.
He married Gertrude Ellen Starling, Ernest Starling's sister, cementing the personal bond that supported their productive scientific collaboration. The two men worked together for more than two decades on problems ranging from pancreatic secretion to vasomotor reflexes.
Key Contributions
- Co-discovery of secretin (1902) with Starling.
- Demonstration that some physiological reflexes are mediated chemically rather than neurally.
- Advocacy for saline solution as treatment for shock during World War I.
- Standard textbook author — his Principles of General Physiology (1915) was influential for decades.
- Successful defense of animal research in the Brown Dog affair.
Timeline
- 1860: Born in Butcroft, West Midlands.
- 1880s: Studies at UCL and Oxford.
- 1888: Joins the UCL physiology department.
- 1902: Discovery of secretin.
- 1903: Brown Dog affair libel case.
- 1912: Appointed Professor of General Physiology.
- 1915: Publishes Principles of General Physiology.
- 1918: Knighted.
- 1924: Dies in London.
Modern Relevance
Bayliss is remembered primarily as half of the Bayliss-Starling partnership that opened the endocrine era. Every hormone discovered since — from insulin and oxytocin to GLP-1 and leptin — rests on the conceptual foundation they established.
His advocacy for saline resuscitation during World War I also connects to modern emergency and critical-care medicine. Isotonic saline, Hartmann's solution, and related crystalloids are direct descendants of Bayliss's wartime recommendations. For related history, see ernest-starling and secretin-first-hormone.
Related Compounds
Related entries
- The Discovery of Bradykinin— Bradykinin, a central mediator of inflammation and vasodilation, was discovered in 1949 by Rocha e Silva, Beraldo, and Rosenfeld in Brazil.
- Ernest Starling— Ernest Starling was the British physiologist who coined the word 'hormone' in 1905 and, with William Bayliss, discovered secretin.
- Secretin: The First Hormone— Secretin, identified in 1902 by William Bayliss and Ernest Starling, was the first molecule shown to act as a hormone and gave the field its name.