The view that the pancreas produces an internal secretion has been generally accepted. No one, however, has been able to obtain from the pancreas an internal secretion and proof of its existence is not complete.
Before reviewing the evidence at hand it would be well to describe briefly the nature and actions ascribed to the internal secretions. The internal secretions are defined as the products of a specific activity of an organ or tissue which pass through the blood to other organs or tissues in which they exert a stimulating or inhibitory influence on the material or energy stored up in the cells. These chemical bodies which form the internal secretions are called hormones, a term derived from a Greek verb, meaning to awake or excite. They are divided by Biedl into the assimilatory and the dissimilatory hormones. The former aid in the upbuilding of the living substance in the
PRATT JH. THE INTERNAL FUNCTION OF THE PANCREAS. JAMA. 1912;LIX(5):322-325. doi:10.1001/jama.1912.04270080004002