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 & Tools strong job they did. The winner of the public vote is then announced as the Red Team, who take home the $50,000 grand prize. Blood, Sweat & Tools Blood, Sweat & Tools is a Canadian television series broadcast on Discovery Channel. The series is hosted by Helder Brum, Rob Koci and Hillary Manion, who also act as the challenge judges and expert advisers to the contestants. The series is the successor of "Canada's Worst Handyman", and has a broadly similar format, but with an emphasis on rewarding competent handiwork rather than finding the nation's worst handyman. The couples are divided