COMPLEMENT 163 



mechanisms might be included under the term adsorption, since 

 they would represent methods of surface binding of matter. 



Thiele and Embleton's Observations. — Another interesting 

 observation concerning tlie union of antibody with antigen is re- 

 ported in an excellent paper by Thiele and Embleton (1914). 

 They showed that a given amount of washed red blood cells is 

 sensitized bj^ definite amounts of antibody regardless of the concen- 

 tration of antibody per cubic centimeter. In other words, if a 

 sensitizing dose of amboceptor is added to one cubic centimeter 

 of salt solution or 20 c.c, it is removed by adding the same unit 

 of red cells to each tube. 



Bordet's and Ehrlich's Views on the Mechanism of Sensi- 

 tization. — As previously stated, Bordet showed that this jn-ocess 

 of sensitization of antigen occurs before complement could bring 

 about lysis, since the latter acted only upon sensitized cells. 

 Bordet concludes from his experiments that complement is adsorbed 

 by the antigen-antibody complex with resulting lysis, while Ehrlich 

 concludes that amboceptor chemically combines with antigen on the 

 one hand and with a combining group of complement on the otlier. 

 The complement is thus enabled to act on the antigen, producing 

 lysis. 



Visible Phenomena op Cell Lysis. — At this point it might be 

 well to visualize what can be seen when an adequate amount of 

 complement is added to various sensitized antigens such as 

 Microspira comma, E. typhosa, immune precipitates and sensitized 

 red cells. 



In the case of a sensitized suspension of living Microspira comma 

 there occurs at 37° C. at first a rounding up of the organisms, fol- 

 lowed by their disappearance. They seem to be almost completely 

 destroyed except for a residual granule. Living sensitized typhosus 

 suspensions are killed, as can be demonstrated by plating methods, 

 but the individual cells frequently appear to be unchanged. Sensi- 

 tized streptococci, staphylococci and also sensitized precipitates 

 seem to show no change. When sensitized red cells are mixed Avith 

 an adequate amount of complement, there occurs after a few 

 minutes a swelling of the cell and liberation of the hemoglobin; 

 the stroma or cell framework remains. 



