Abstract
In order to test the possibility of there being more than one immunological type of fibrinolytic streptococci, 40 local strains of Streptococcus hemolyticus were titrated against various specimens of normal and immune human plasma-clot. To make these titrations parallel Tillett-Garner tests 1 were run with 1:1, 1:2, 1:4, 1:8, and 1:16 dilutions of 24-hour broth filtrates of the strains in question. The maximum dilution giving distinct fibrinolysis by the end of 24 hours was recorded as approximate lytic titer for a given blood sample. A preliminary series of duplicate tests showed that the experimental error in such titrations is not greater than one dilution either way from the recorded titer.
Data from 2 typical titrations are recorded in Table I. The 2 immune plasmas here recorded were drawn from convalescent cases, one of 90 days', the other of 12 months' duration.
Adopting the plasma-clot Van. as the arbitrary standard, the table shows a normal range of fibrinolytic susceptibility of human blood varying from 4 times to 0.6 of the arbitrary standard.
There is apparently but one fibrinolytic type among the 40 streptococcus strains tested. The immune plasmas are consistently resistant
to all strains. Within the limits of the experimental error (one dilution, plus or minus) all normal plasmas are consistently susceptible.
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