This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Konstantin Tretiakoff ca. . Konstantin Tretiakoff Lees AJ Selikhova Andrade LA Duyckaerts The black stuff and Konstantin Nikolaevich Tretiakoff Mov Disord PMID ca author I've mailed the authors of this article and obtain information that it's unknown who has taken this photograph It's safe to assume that it's in public