CALVIN B. COULTER 



779 



20 



10 







pH 7.2 70 6.8 6.6 6.4 6.2 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 



Fig. 6. The complementary activity in the presence of unheated end-piece 

 of the euglobulin (mid-piece) fraction heated separately in distilled water at 

 different reactions. 



Fig. 7. The complementary activity of whole serum heated at different reac- 

 tions in isotonic saline solution. The individual variation in thermolability is 

 shown by the different maxima reached in the two experiments recorded here, 

 the lower values b.eing given in this case by the serum which was heated to the 

 lower temperature. 



