Santiago Ramón y Cajal. The photo is a self-portrait that Cajal took at his home, in Valencia, about 1885. At that time, Cajal was a professor of Anatomy at the University of Valencia and used to teach histology, in a private way, at his home. For that reason, several microscopes can be seen on the table.
Please credit: Cajal Institute, Neuroscience Research Center of the Spanish National Research Council