The demonstration of the physiologic importance of the pancreatic gland quite aside from the so-called external secretion, the pancreatic juice, which it elaborates, has raised numerous important questions. The fact that a glandular epithelial structure is provided with an outlet in the form of secretory ducts for its special products by no means excludes the simultaneous possibility of the elaboration of an "internal secretion" that finds its way directly into the circulation. Indeed, the discovery of such possibilities has made it necessary to search for evidences of "internal secretion" or hormone production on the part of many organs. In the case of the salivary glands it is usually stated, on the basis of extirpation experiments on animals, that these racemose epithelial structures are not indispensable to life. Survival of persons after complete gastrectomy affords indication likewise that the gastric glands are not a sine qua non of existence.
THE EFFECTS OF LOSS OF BILE AND PANCREATIC JUICE. JAMA. 1927;88(2):102. doi:10.1001/jama.1927.02680280032013