344 CYTOLYSINS 



but not with other bacterial species or other cells. As to the specificity 

 of complement, opinions differ. Ehrlich believes that there are many 

 complements, as, e. g., one for a particular hemolytic amboceptor, an- 

 other for a bacteriolytic amboceptor, and so on through the extensive 

 list of known amboceptors. Bordet, on the other hand, believes that 

 there is but one complement, which will act with any amboceptor. 



Bordet's conception of the mechanism of this order of antibodies is 

 also different from that of Ehrlich. Both agree that the antibody pre- 

 pares the cell for the lytic action of a complement, but Ehrlich holds 

 that the antibody acts as a simple link between antigen and comple- 

 ment, whereas Bordet believes that the antibody acts as a mordant or 

 dye, penetrating its antigen, and sensitizing or preparing it for the action 

 of the complement. For this reason Bordet calls these antibodies 

 " sensitizers," or substances sensibilisatrice. The term " sensitizing " is 

 now in general use, and is employed especially in hemolytic tests when 

 corpuscles or bacteria are mixed with their amboceptors to effect their 

 union. It is expressive and satisfactory, and may be used without 

 necessarily subscribing to Bordet 's view. 



Metchnikoff believes that amboceptor or his "fixator" is found in 

 the leukocytes. He asserts that the amount of fixator or amboceptor 

 produced is proportional to the amount of phagocytosis and phagolysis 

 that occur during the absorption of the antigen. Metchnikoff considers 

 the fixators as analogous to enterokinase, and he believes that, like the 

 latter, the fixator acts as an accessory digestive ferment, having for its 

 object the linking of the more potent ferment, as a cytase or comple- 

 ment, to the cell or molecule to be digested. 



Formation of Amboceptors. While experimental data are at hand 

 to show that amboceptors may be produced by local tissues, it is entirely 

 probable that in wide-spread infection or as the result of artificial im- 

 munization there is general cellular activity with extensive antibody 

 formation. The spleen and hematopoietic tissues in general and the 

 mononuclear leukocytes are regarded by many as being particularly 

 active in the formation of hemolysins and bacteriolysins (Pfeiffer and 

 Marx, Deutsch, Wassermann). 



As has been stated, Metchnikoff believes that antibodies of the class 

 under consideration are the products of the leukocytes, thus tending to 

 preserve the importance of the phagocytic theory. While there is little 

 doubt that the various leukocytes, endothelial cells, and other phag- 

 ocytic cells are sources of amboceptor production, there is no reason for 

 accepting the belief that their formation is confined strictly to these cells. 



