Bayliss, Sir William (1860-1924), an English biologist, helped discover hormones. Hormones are chemical substances that regulate many body functions. Bayliss specialized in physiology, the study of life functions, such as digestion. In 1902, he and another physiologist, Ernest Henry Starling, became the first scientists to find a hormone, which they named secretin. Secretin is produced in the small intestine, and it stimulates the pancreas to secrete digestive juices. This discovery led Bayliss and Starling to recognize how hormones functioned. In 1905, Starling coined the term hormone, which comes from a Greek word meaning to set in motion.
In addition to his work on hormones, Bayliss studied how the heart, blood, and blood vessels work. During World War I (1914-1918), he found a way to replace lost blood with a saline solution. This solution helped save the lives of thousands of wounded soldiers.
William Maddock Bayliss was born on May 2, 1860, in Wednesbury, near Wolverhampton, England. He received a doctor’s degree from Oxford University in 1888 and taught at University College in London from 1888 to 1924. His most important book was Principles of General Physiology (1915). Bayliss was knighted in 1922. He died on Aug. 27, 1924.
