BACTERIAL ANAPHYLAXIS 425 



In the earlier work of Friedberger, Neufeld and Dold, and others the 

 poisons were formed from the bacteria by the action of alexin at 

 low temperatures. This suggested the possibility that the alexin 

 fractions "Endstiick" and "Mittelstiick" might not both be in- 

 volved in the reaction, since, from previous studies, it was known that 

 at low temperatures the midpiece (the globulin fraction) was bound, 

 but that the end piece did not become active until the temperature 

 was increased. This point was, therefore, made the object of a 

 special investigation by Friedberger and Ito, 30 who found that 

 neither fraction alone would suffice, but that bacterial anaphylatoxins 

 were formed only under the influence of the intact whole alexin, or 

 by that of the two fractions, reunited after separation. 



Because of the reasoning along which the investigations of ana- 

 phylatoxin formation were developed, it is not surprising that it 

 seemed self-evident that the matrix of the poison was represented by 

 the bacterial protein the antigen of the lytic complex. The only 

 fact which, in the earlier experiments, might have cast some doubt 

 upon this was the ease with which anaphylatoxins were produced 

 from boiled bacteria and precipitates and from such very insoluble 

 organisms as the tubercle bacillus. 



Such vague suspicion' becomes a very definite doubt, however, 

 in the light of the experiments of Keysser and Wassermann. 31 

 Keysser and Wassermann utilized the fact that certain serum ele- 

 ments may be absorbed out of serum if this is shaken up with such 

 indifferent suspensions as barium sulphate or kaolin (aluminium 

 orthosilicate). 32 They therefore substituted these insoluble sub- 

 stances for antigen, allowed them to absorb serum constituents, as- 

 sumed by them to be amboceptor, out of normal and inactivated im- 

 mune sera, and then allowed complement or alexin to act upon the 

 "sensitized" kaolin. 



In this way they obtained active and powerful anaphylatoxin, 

 and claim, in consequence, that the matrix of the poison is not in 

 the bacterial antigen, but in the sensitizer or amboceptor, which is 

 mechanically absorbed by the bacteria (as by the kaolin), and thus 

 made amenable to the alexin action. 



The experiments of Keysser and Wassermann have found con- 

 firmation in the hands of other investigators, although the results of 

 Neufeld and Dold, as well as our own, with this method were far 

 more irregular than were those of Keysser and Wassermann. 



30 Friedberger and Ito. Zeitschr. f. Immunitatsforsch., Vol. 11, 1911. 



31 Keysser and Wassermann. Folia Serologica, Vol. 7, 1911 ; Zeitschr. 

 f. Hyg., Vol. 68, 1911. 



32 Kaolin emulsions will absorb amboceptor only out of diluted serum. 

 Out of concentrated serum complement is completely absorbed. Friedberger 

 u. Salecker, Zeitschr. f. Immunitatsforsch., Vol. 11, 1911; Zinsser, from 

 Journ. Exp. Med., Vol. 18, 1913. 



