In vitro and local coagulation of heparinized and citrated blood from skin wounds

1. Citrated blood perfusing a dog hind leg preparation as well as heparinized blood in the whole animal, has the capacity to clot in glass capillary tubes when collected from skin wounds, in spite of its incoagulability when withdrawn from large vessels. This phenomenon is generally observed after the first minute of bleeding. 2. lilood left untouched in a wound docs not form a massive clot but only a thin pellicle at the blood air interface. The pellicle becomes progressively thicker but the blood below remains uniformly fluid. The time taken for the formation of this pellicle is twice to three times as long as that required for bleeding arrest.