AMBOCEPTORS 319 



completes the reaction after being linked with the antigen. The term 

 "alexin" was first applied by Buchner to the germicidal substance found 

 in normal serum. We now know that Buchner was working with both 

 amboceptor and complement, although Bordet was the first to discover 

 the former, Buchner having been unconsciously most interested in the 

 thermolabile complement. 



To the antibody itself the term substance sensibilisatrice has been 

 applied by Bordet, for he believes that this antibody sensitizes or pre- 

 pares the cell for the action of the alexin or complement. The following 

 names have been applied to the antibody by various observers : fixateur, 

 by Metchnikoff; preparator, by Muller; and amboceptor, interbody, and 

 immune body by Ehrlich. Of these, the term " amboceptor" is in most 

 general use, signifying a two-armed body that unites antigen on the one 

 hand, with a complement on the other. 



When using the term amboceptor, care should be used to designate 

 its specific character; thus, for example, a hemolytic amboceptor and a 

 bacteriolytic amboceptor mean respectively a hemolysin and a bacterio- 

 lysin. 



It is common practice to designate an amboceptof according to the 

 cell for which it has a special affinity; thus antisheep amboceptor or 

 hemolysin means an amboceptor for sheep cells, the prefix "anti" being 

 affixed because it is destructive for those cells. 



AMBOCEPTORS 



Although antitoxins have received considerable study from a thera- 

 peutic standpoint, probably no order of antibodies has beeA given*more 

 attention than the cytolysins have received, not only because of theif ** 

 vast therapeutic possibilities, but also from their value as an aid to* diag- 

 nosis. The hemolysins especially have been utilized v in Baking the 

 Wassermann test for syphilis and similar reactions, the very nature of the 

 phenomenon offering a visible and fascinating njtrtod of study. 



Since the general structure, formation, a^d'action of the various am-* 

 boceptors, such as the bacteriolysins, hemolysins, and other cytolysins, 

 are essentially similar, the general character of amboceptors may be here 

 considered, a study of the special characteristics of each being reserved 

 for subsequent chapters on the more important members of the group. 



Historic. The alexins or complements were first discovered through 

 the researches of Nuttall and Buchner in 1889. The amboceptors were, 

 of course, present in the various serums with which these observers were 



