silent organ

A popular term for the pancreas which refers to the relative paucity of clinical signs seen in pancreatic disease, especially with tumours of the body and tail, until disease process has reached an advanced stage
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

silent organ

Surgery A popular term for the pancreas, and the relative paucity of clinical signs when it has disease, especially, in tumors of the body and tail. See Whipple's operation.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
References in classic literature ?
There it would have stood solitary, or with no livelier companion than the silent organ, in the opposite gallery, six days out of seven.