<Li> Blue Blood (1925 film), a 1925 silent film </Li> <Li> Blue Blood (1973 film), a British horror film directed by Andrew Sinclair </Li> <Li> Blue Blood (2006 film), a 2006 documentary film directed by Stevan Riley </Li> <Li> Blue Blood (2008 film), a 2008 film directed by Brett Ratner </Li>

Where did the term blue blood come from