COMPLEMENT FIXATION 179 



be demonstrated in addition to agglutination. Most of the preceding 

 experiments indicate that the phenomena of precipitation and comple- 

 ment fixation are not necessarily associated, but, on the other hand, 

 cannot be interpreted to indicate that the immune serum contains two 

 different immune bodies. Friedberger and Liefmann, working inde- 

 pendently, showed, however, that heating an immune serum to 67 C. 

 can destroy the precipitin in the serum without altering the capacity 

 of the serum for participating in complement fixation. This experiment 

 has been interpreted as indicating that precipitating and complement- 

 fixing bodies represent independent activities but not necessarily that 

 they are different bodies. Muir and Martin found that upon immuniz- 

 ing animals they were able to demonstrate that the serum of these 

 animals contained complement-fixing' powers earlier than precipitins 

 could be demonstrated. Altmann found that complement-fixation 

 bodies appeared earlier than agglutinins for paratyphosus B and colon 

 bacilli but with the use of typhoid bacilli both bodies appeared about 

 the same time. As a converse of this demonstration, Moreschi im- 

 munized birds with rabbit serum and found in contravention to his 

 earlier work that he was able to produce a precipitin of very high titer 

 without being able to demonstrate the power of complement fixation on 

 the part of the immune serum. This was corroborated by Sobernheim. 

 Liefmann was able to show a certain amount of difference in the activity 

 of immune serum. He brought the immune serum in contact with the 

 antigen at o C. for sufficient time to produce a considerable amount 

 of precipitate. He then centrifuged the precipitate and found that the 

 supernatant fluid at 37 C. was capable of fixing complement. Lebailly, 

 by the fractional addition of antigen to the precipitating immune 

 serum, was able apparently to separate the precipitating and comple- 

 ment-fixing bodies. Arlo precipitated the antigenic and immune sera 

 by means of CO 2 , thereby obtaining the globulins in the precipitate. 

 In both instances the complement-fixing body was found in the redis- 

 solved globulin fraction and the precipitating body was found in the 

 supernatant fluid. This has been controverted by Bruynoghe, who 

 maintains that euglobulins are capable of producing non-specific fixa- 

 tion. Reviewing all this experimental evidence, it seems perfectly 

 clear that complement fixation can and does occur independently of 

 visible precipitation, a statement supported by a great mass of more 

 recent investigation of the subject. None of these experiments, how- 

 ever, can be safely interpreted as indicating that there are two separate 

 bodies in the immune serum. Neufeld and Handel, however, appear to 

 be definitely of the opinion that there are two separate bodies concerned. 

 They found that sensitized cholera spirilla are capable of fixing the 

 hemolytic complement at o C. but that at 37 C. the organisms will 

 fix both hemolytic and bacteriolytic complement. They explain this 

 by assuming that the fixation at higher temperature is due to the bacteri- 

 cidal amboceptor but that the fixation at o C. is due to a separate sub- 

 stance which they named the Bordet antibody. Such experimental 

 evidence cannot be accepted as final. Sachs states that a priori it can 



