2 Pages in Charles Darwin's Library associated with "mental states - frowning"

  1. The anatomy and philosophy of expression.
    By: Bell, Charles.
    Publication info: London :John Murray,1844.
    Pages: Page 137  
  2. Elements of physiology.
    By: Müller, Johannes. - Baly, W.
    Publication info: London :Taylor & Walton,1838-1842.
    Volume: v.2
    Pages: Page 1144