150 PerspecfJves in Microbiology 



led, with Weil and Treffers, to a theory of complement 

 fixation which has not yet been refuted. But we are only 

 beginning to learn how complement mediates the lysis of 

 cells that have taken up antibody. Manfred Mayer has 

 made a good case for the concept that the antibody is the 

 enzyme and that complement merely supplies cofactors or 

 energy. This view is directly opposed to the usual one that 

 complement or one or more of its components exerts enzy- 

 matic action on the cell-antibody complex. Progress is, 

 however, being made on the mechanics and kinetics of 

 lysis with the aid of new methods devised by Mayer and 

 his group. These workers have also shown that the initial 

 step of fixation of a portion of complement requires cal- 

 cium ion and that this is followed by a second prelytic 

 stage of complementary activity requiring magnesium ion. 

 Only then can lysis ensue. In our laboratory, Plescia is 

 working out the thermodynamics of immune lysis, is study- 

 ing the long-known concentration effect and the range in 

 which lysis is independent of this effect, and has simplified 

 the analytical problem so that large numbers of accurate 

 tests and readings may be made by a single worker. Both 

 approaches appear to be converging toward similar views 

 of the mechanism of immune lysis, but much patient effort 

 and time will still be required before a detailed picture of 

 the complex events can be obtained. Perhaps the final 

 solution may even be delayed until methods for the frac- 

 tionation of closely related proteins are so improved that 

 complement and its four recognized components can be 

 isolated in a state of purity. 



Relation of Allergy fo I mm unify 



As for allergy, we are all familiar with its distressing ef- 

 fects in man and domestic animals, but little is known of 

 the mechanisms of these effects. Is allergy a process running 

 parallel with immunity; is it an imperfect immunity in the 



