ANTI-ENZYME IMMUNITY 273 



matically active new molecule. It may here be suggested that the role 

 of streptococcal factor in the lytic process may represent a simple 

 process or splitting of the already structurally complete proteolytic 

 enzyme from an easily dissociable combination with a substance which 

 blocks the enzymatic activity. 



Many years ago, Nolf (1908) observed that fibrinolytic activity was 

 obtained when recalcified plasma was shaken with chloroform. Several 

 investigators (Jobling and Peterson, 1914; Minot, 1915; Yamakowa, 

 1918) observed that when serum was treated with chloroform or other 

 organic solvents the anti-trypsin (or antithrombin) was removed, pro- 

 ducing autodigestion or proteolytic action (Yamakowa, 1918). These 

 observations have recently been reinvestigated and considerably ex- 

 tended (Patek and Taylor, 1937; Tagnon, 1942; Tagnon, et al., 1942; 

 Kaplan, et ah, 1942; Kaplan, 1944). These investigators reported that 

 when platelet-free normal human plasma, claimed to be free from active 

 calcium ion, is treated with chloroform, the euglobulin fraction of the 

 plasma demonstrates the property of lyzing both fibrin and fibrinogen. 

 At low concentration of the chloroform-activated globulin, clotting 

 of fibrinogen occurred, while at higher concentration the clotting 

 was followed by fibrinolysis, and at still higher concentrations fibrino- 

 genolysis occurred with no clotting. Chloroform treated plasma also 

 digested gelatin, casein and hemoglobin, forming non-protein nitrogen 

 (Kaplan, et al, 1942; Kaplan, 1944). They stated that the activity 

 of the chloroform treated plasma resembles, in some respects, that of 

 trypsin in its action on plasma, fibrinogen and prothrombin by causing 

 the clotting of the oxalated blood and fibrinogen solution followed 

 by lysis of the fibrin clot. 



The above findings are helpful for the understanding of the nature 

 and the manner with which the so-called bacterial, more specifically 

 streptococcal, fibrinolysins function. In the absence of serum lytic fac- 

 tor, as Milstone (1941) first demonstrated, bacterial factor has no 

 effect on the lysis of fibrin. Christensen (1945) proposed that bacterial 

 factor catalytically activates the serum lytic factor. 



Christensen and MacLeod (1945) referred to the already observed 

 facts that certain non-specific agents, such as organic solvents, acid 

 precipitation, treatment with urea, benzoate, thiocyanate and cresols, 

 activate serum lytic factor. Schmitz (1937) attributed the activation 

 of lytic factor resulting from treatments with alumina gel, or dialysis in 



