With the purpose to elucidate the cause and difference of blood fluidity in sudden death and natural one, we have observed the fibrinolysis of the blood in medico-legal and pathological autopsies by means of Fibrin Plate Method, a
routine method devised in our laboratory. As the result it has been found that in the blood serum of sudden death and
in some of natural deaths from tumors, leukemias, etc., the decrease in fibrinolytic activity is equivalent to the amount of proactivator that combined with the SK-like substance liberated into blood. On the other hand, in the blood of most of natural deaths, and in that bled from vessels and stored in body cavities, no natural fibrinolysis is observable and the same fibrinolytic activity with SK as normal one is demonstrated. Thus it is concluded that the cause of blood fluidity in sudden death is due to the fibrinolysis.
