THE FIXATION OF ALEXINS. 351 



To each tube is added alexin of the guinea-pig one-thirtieth of a 

 cubic centimeter, and contact allowed for one-half hour. In tube 1 

 a considerable precipitate is formed; in tube 2, none. Then to 

 each tube is added 0.05 of a cubic centimeter of ox corpuscles 

 sensitized with S. rabbit > ox, 55 degrees (1| hemolytic doses). 



Resultant Hemolysis. 



Tube 1. No hemolysis. 

 Tube 2. Hemolysis complete. 



Which shows that the precipitate has fixed the guinea-pig alexin. 



II. 



That a disregard of this fixation of alexin by specific precipitates 

 has led to many erroneous impressions of the mechanism of hemoly- 

 sis will undoubtedly prove true, but I wish to commit myself only 

 on such phases of the question as I have been able to submit to 

 experimental study. 



Recently Pfeiffer and Friedberger* have given the resume of a 

 study of the antibacteriolytic, or "antagonistic," substances which 

 are said to occur in normal sera. These authors have found that 

 certain normal sera, which in themselves possess no antilytic proper- 

 ties, acquire distinct antibacteriolytic power when previously put 

 in contact with the bacteria on which they are destined subsequently 

 to act. For example, normal rabbit serum treated with typhoid 

 bacilli has the power to prevent in vivo the destruction of sensitized 

 typhoid organisms; untreated serum has no such power, nor does 

 the serum treated with typhoid bacilli show any antilytic effect 

 for cholera vibrios sensitized with anticholera serum. A further 

 consideration of these most interesting observations concerning 

 bacteria need not concern us here, but an analogous series of facts 

 in hemolysis, which was soon published by Sachs, f and the con- 

 clusions of this author must be regarded more in detail. Normal 

 rabbit serum heated to 55 degrees when treated with equal parts 

 of sedimented red blood corpuscles of the sheep or of the pig inhibits 

 the action of guinea-pig alexin on the properly sensitized corpuscles 

 of the blood in question. Normal untreated serum has no such 



* Pfeiffer und Friedberger, Deutsche med. Wochenschr. , 1905, No. 1, p. 6. 

 t Sachs, Deutsche, med. Wochenschr., 1905, No. 18, p. 705. 



