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 & Tears (Blood, Sweat & Tears album) Blood, Sweat & Tears (Blood, Sweat & Tears album) Blood, Sweat & Tears is the second album by the band Blood, Sweat & Tears, released in 1968. It was commercially successful, rising to the top of the U.S. charts for a collective seven weeks and yielding three successive Top 5 singles. It received a Grammy Award for Album of the Year in 1970 and has been certified quadruple platinum by the RIAA with sales of more than four million units in the U.S. In Canada, it enjoyed four runs and altogether eight weeks at No. 1 on the "RPM" national