THE FIXATION OF ALEXINS. . 355 



Contact, three-quarters of an hour at room temperature, and 

 then the following tubes are made: 



Tube 1. A 1 mixture 1.1 c.c. 



Serum rabbit > ox, 55 degrees 0.4 c.c. 



Tube 2. A 1 mixture 1.1 c.c. 



Serum normal rabbit, 55 degrees 0.4 c.c. 



Tube 3. B 1 mixture 1.1 c.c. 



Serum rabbit > ox, 55 degrees 0.4 c.c. 



Tube 4. B 1 mixture 1.1 c.c. 



Serum normal rabbit, 55 degrees 0.4 c.c. 



After contact, a precipitate is seen in tube 1 but none in tubes 

 2, 3 and 4. Then to each tube is added 0.05 of a cubic centimeter 

 of washed sheep corpuscles sensitized with S. rabbit > ox, 55 degrees, 

 and with the excess of the immune serum removed by centrifugaliz- 

 ing. 



The resultant hemolysis is as follows: 



Tube 1. No hemolysis. 



Tubes 2, 3 and 4. Hemolysis complete. 



This experiment clearly demonstrates that the so-called "am- 

 boceptor anticomplement " action of Sachs is simply due to specific 

 precipitates. 



As will suggest itself, the alexin-fixing action of serum precipitates 

 may readily be brought forward to explain the Neisser-Wechsberg 

 phenomenon of " complement deviation." This, it will be remem- 

 bered, was demonstrated in the case of bacteria, where it was found 

 that an excess of immune serum prevented the complete destruction 

 of a given dose of bacteria by an amount of alexin that destroyed 

 perfectly the same amount of organisms if the optimal dose of 

 immune serum were used. The authors reconciled these experi- 

 ments with the Ehrlich hypothesis by supposing that the mass 

 action of the excess of free amboceptor deviated the complement. 

 But no one has been able to demonstrate the hemolytic analogue 

 of this phenomenon. Morgenroth,* it is true, by making certain 

 suppositions as regards the union of " complements " with free 

 amboceptors, and by introducing certain other bodies ("antiam- 

 boceptors"), has obtained somewhat similar results, but his analogy 

 is far from exact. The discussion of this subject, together with 

 * Morgenroth, Centralbl. f. Bakt., etc., Bd. XXXV, 1904, p. 504. 



