Studies on identification of menstrual blood stain by fibrin-plate method. I. A study on the incoagulability of menstrual blood

As the results of present study on plasmin in menstrual blood by means of the Fibrin-Plate Method, a large amount of plasmin as much as dilution of 1: 100 or 1:1,000 of the menstrual blood serum, has been found in a natural form and it is deduced that the incoagulability of menstrual blood is the result of the plasmin formation in the same blood serum. Further, it has been recognized that this plasmin is found in a rather large quantity in the blood of the second menstrual day and it is decreased by the fifth day. In addition, the plasmin of menstrual blood is contained in the globulin fraction of the same serum, especially markedly in β-globulin fraction. On the other hand, it has also been clarified that in the circulating blood during menstruation no plasmin is present in natural state and that a large quantity of inactive plasminogen still exists in menstrual blood.