228 INFECTION AND IMMUNITY 



occurred; yet, centrifugalized at this temperature, immune body was 

 found to have become bound to the corpuscles, the complement re- 

 maining free in the supernatant fluid. If the same mixture, however, 

 was exposed to 37° C, hemolysis promptly occurred. 



From these facts, Ehrlich concluded that complement did not direct- 

 ly combine with the corpuscles, but did so through the intervention of 

 the immune body. This immune body, he reasoned, possessed two 

 distinct atom-groups or haptophores; one, the cytophile haptophore 

 group, possessing strong chemical affinity for the red blood cell; the 

 other, or complementophile haptophore group, with weaker avidity 

 for the complement. Because of this double combining power, Ehrlich 

 speaks of the immune body as " amboceptor." His views as to the nature 

 and action of immune body and complement are graphically represented 

 in Figs. 57 and 58 (p. 227). 



From what has been said before, it will be seen that the fundamental 

 difference between the conceptions of the mechanism of the lytic proc- 

 esses as held by Bordet and by Ehrlich lies in the ability of the alexin 

 or complement to act directly upon the antigen, as claimed by Bor- 

 det, or, as Ehrlich holds, only through the intermediation of the im- 

 mune body. Bordet's views,' by no means disproved and still held by 

 many bacteriologists, may be summed up in his own words as follows: 

 " Neither immune body nor antigen (bacterium, blood cell, etc.) alone 

 has any manifest affinity for alexin (complement) ; but, united, they 

 form a complex which can absorb alexin." The absorption of comple- 

 ment is thus conceived as a property of the immune body or amboceptor 

 (or, in Bordet's language, sensitizer) plus its specific antigen — acting as a 

 complex and not through a complementophile group of the immune body. 



AGGLUTININS 



Although MetchnikofI ^ and Charrin and Roger ^ had noticed pecul- 

 iarities in the growth of bacteria when cultivated in immune sera, which 

 were unquestionably due to agglutination, the first recognition of the 

 agglutination reaction as a separate function of immune sera was the 

 achievement of Gruber and Durham. While investigating the Pfeiffer 

 reaction with B. coli and the cholera vibrio, Gruber and Durham ^ 



^Bordet, A Rfeum^ of Immunity in " Studies in Immunity." Trausi. by Gay, 

 Wiley & Son, 1909. 



' Metchnikoff, " fitudes sur I'imraunit^," IV Memoir, 1891. 

 3 Charrin et Roger, Compt. rend, de la soc. de biol., 1889. 

 * Gruber und Durham. Munch, med. Woch., 1896. 



