William Bayliss. Portrait of William Maddock Bayliss (1860-1924), British physiologist and co- founder of endocrinology. Bayliss spent most of his career working at University College London with E.H. Starling, a fellow professor. Together they studied the nervous system, the vascular system and the movement of food down the intestine. They discovered that pancreatic secretions are controlled by a chemical, which they named secretin. This chemical was produced in the duodenum part of the intestine and was carried to the pancreas in the blood. Bayliss' work began the study of such messenger chemicals or hormones.