Scientific Proceedings (114). 



Thus the first series were run both at water-bath and ice-box 

 temperatures with the following fixation periods: 15 minutes, 

 30, 45, 60, 90 and 120 minutes. In view of the fact that comple- 

 ment has a tendency to be destroyed when exposed for too lengthy 

 periods in the water-bath, the fixation tests at this temperature 

 were not extended beyond 2 hours. Neither were the fixation 

 periods extended beyond this time when the fixations were at 

 room temperature. In the case of the ice-box, however, the 

 fixation periods were continued for 3, 4, 5 and 6 hours, and occa- 

 sionally longer. At the end of each fixation period, standard 

 amounts of sheep cells and amboceptor were added to each set 

 and placed in the water-bath to determine whether or not the 

 complement had been "fixed." 

 The results indicate: 



(1) That the phenomenon of fixation of complement goes on 

 equally well at water-bath, room or ice-box temperature. 



(2) That from 50 to 75 per cent, of fixation takes place during 

 the first hour and that fixation is completed in the neighborhood 

 of 4 hours at ice-box temperature. 



82 (1664) 



The quantitative relation between complement and 

 complement fixing antibody. 



By R. L. KAHN. 



[From the Bureau of Laboratories, Michigan Department of Health, 

 Lansing, Michigan .] 



In the course of investigation on precipitin and complement 

 fixing antibodies produced by injections of edestin, it was observed 

 that, while the serum of a rabbit immunized with this protein 

 showed the presence of precipitin antibodies, it did not show any 

 complement fixing antibodies when employing the usual 2 units 

 of complement in the fixation tests. It appeared reasonable at 

 first to accept this finding as evidence of the lack of relation 

 between these two types of antibodies. It seemed, however, that 

 possibly the employment of 2 units of complement in the tests 

 might give a sufficient excess of this ingredient to render a serum 



