Blood blood clotting in a transparent container. When blood is drawn in a glass container and left undisturbed for about an hour, four different layers can be seen. A dark clot forms at the bottom (the "black bile"). Above the clot is a layer of red blood cells (the "blood"). Above this is a whitish layer of white blood cells (the "phlegm"). The top layer is clear yellow serum (the "yellow bile"). The ABO blood group system was discovered in the year 1900 by Karl Landsteiner. Jan Janský is credited with the first classification of blood into the four types (A,
Blood, Sweat and Tears (album) Blood, Sweat and Tears (album) Blood, Sweat and Tears is the fifteenth album by singer Johnny Cash, released in 1963 (see 1963 in music). It is a collection of songs about the American working man. This includes "The Legend of John Henry's Hammer" and "Busted", the latter of which would become a single. Both would also be performed by Cash during his famous 1968 concerts at Folsom Prison and be included in the 1999 extended reissue of the album, "At Folsom Prison". The album was included on the Bear Family Records box set "Come Along and Ride This Train". Additional