Secretin

Cutting all the nerves leading to the pancreas did not prevent it from working. This led to the discovery that the small intestine lining secreted "secretin", under the influence of scomath acid. Starling and Bayliss had discovered that it was possible for chemical messages as well as nerve messages to exist in the body. This finding laid the foundation for the study of hormones in the body.
 Ernest Henry Starling and William Maddock Bayliss England 1902 Secretin

Cutting all the nerves leading to the pancreas did not prevent it from working. This led to the discovery that the small intestine lining secreted "secretin", under the influence of scomath acid. Starling and Bayliss had discovered that it was possible for chemical messages as well as nerve messages to exist in the body. This finding laid the foundation for the study of hormones in the body.