Photograph of Silas Weir Mitchell, 1881. This image is in the public domain in the United States because its copyright has expired. From Images from the History of Medicine: http://ihm.nlm.nih.gov/luna/servlet/detail/NLMNLM~1~1~101433810~184749:-Silas-W–Mitchell-?qvq=q:Mitchell+;lc:NLMNLM~1~1&mi=41&trs=68. Courtesy of Wikimedia Commons: http://en.wikipedia.org/wiki/File:Silas_Weir_Mitchell.jpg
