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 & Heels Blood, Sweat & Heels Blood, Sweat & Heels is an American reality television series that premiered on January 5, 2014, on Bravo. It depicts the personal, professional, and social circle of several women who all reside in New York City. The premiere episode of "Blood, Sweat and Heels" ranked as a network best for a series premiere on Bravo at that time, averaging 2.5 million viewers and 1.4 million in the adults 18-49 viewership demo. The cast of the first season included Melyssa Ford, Demetria Lucas, Brie Bythewood, Mica Hughes, Daisy Lewellyn, and Geneva S. Thomas. The season concluded on