Attribution : 

By Unknown author - [1], Public Domain, https://commons.wikimedia.org/w/index.php?curid=11647284

By Unknown author - Images from the History of Medicine (NLM), Public Domain, https://commons.wikimedia.org/w/index.php?curid=11371821

By Jan Verkolje - http://www.rijksmuseum.nl/collectie/SK-A-957, Public Domain, https://commons.wikimedia.org/w/index.php?curid=34320547

By Unknown author - http://ihm.nlm.nih.gov/images/B25666, Public Domain, https://commons.wikimedia.org/w/index.php?curid=19353800

By Medico-Legal Society of New York(Life time: 1885) - Original publication: 1885Immediate source: https://books.google.com/books?id=T7RXAAAAMAAJ&dq=paul+zacchias&source=gbs_navlinks_s, Public Domain, https://en.wikipedia.org/w/index.php?curid=35865006

By Rudolf Krziwanek - Österreichische Nationalbibliothek, Bildarchiv Austria, Inventarnr. Pf 9385:B (3), Public Domain, https://commons.wikimedia.org/w/index.php?curid=13908867

By Georg Bartisch - University of Oklahoma, Public Domain, https://commons.wikimedia.org/w/index.php?curid=26189896

By Anne-Louise Moreau, dite Anna Mérimée (1775-1852), mother of Prosper Mérimée - Bridgeman Art Library, Public Domain, https://commons.wikimedia.org/w/index.php?curid=8922023

By Photogravure after Lafayette. - [1], CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=33167354

By [1] Originally from en.wikipedia; description page is/was here., Public Domain, https://commons.wikimedia.org/w/index.php?curid=403227

George Grantham Bain Collection (Library of Congress), Public domain, via Wikimedia Commons https://commons.wikimedia.org/wiki/File:Abraham_Jacobi_1912.jpg

By "Photo by Kurtz, Engraved by R. O'Brien" - "Kurtz" is presumably William Kurtz (1833 - December 5, 1904); "R. O'Brien" may be "Lucius R. O'Brien", an engraver active at that time. - http://ihm.nlm.nih.gov/images/B23841, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18968624

By Cleaned up version of image hosted on Google Image Search. This image comes from the Google-hosted LIFE Photo Archive where it is available under the filename 6b3da250c6b5560f. Public Domain, https://commons.wikimedia.org/w/index.php?curid=5985289

By Painting by unknown, Photographed by A. C. Cooper. - http://catalogue.wellcome.ac.uk/record=b1162089, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4207153

By Mezzotint by R. Houston after A. Ramsay - [1] [2], CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=19211358

By Unidentified engraver - 1881 Young Persons' Cyclopedia of Persons and PlacesUpload by RedWolf 05:45, Jan 10, 2005 (UTC), Public Domain, https://commons.wikimedia.org/w/index.php?curid=164808