192 MANUAL OF BACTERIOLOGY. 



the free immune body, the precipitated, washed red cells disintegrate when 

 fresh complement — i. c, fresh serum — ^is added. 



From these and other considerations Bordet regards lysin as composed of 

 a specific antibody, sensibilisatrice or immune body of EhrUch, on the one hand, 

 and of a cytolytic, bacteriolytic, hemolytic alexin proper or complement of 

 Ehrlich, on the other. The immune body is specific, but it does not cause 

 destruction of cells by itself: it does so only in conjunction with complement 

 or alexin. Alexin is not strictly specific, and it has some cytolytic power, as 

 seen in normal blood independently of substance sensibilisatrice. But its power 

 is greatly enhanced if the cells acted upon are first sensitized by sensibilisatrice. 



The reactions found by Bordet may be briefly summarized as follows: 



Bacteria or other cells which are united to the same immune body or sen- 

 sibilisatrice become disintegrated upon the addition of diverse complements. 



In any one cytolytic serum the complement for bacteria and for red cells 

 is one and the same. The fixation of the immune body takes place by the 

 stroma of the red cells, for red cells washed of all their contents so that only 

 the empty capsules are left fix the immune body just as well as unwashed red 

 cells. 



Antilysin combines with both immune body and complement. 



Since antilysin neutrahzes the complement, it is both antihemolytic and 

 antibacteriolytic, because the complement for both of these is the same. 



Pfeiffer was the first to describe the bacteriolytic action of animal fluids on 

 bacteria, and the reaction is called Pfeiffer's phenomenon. Pfeiffer's view of 

 the nature of lysin differs from those of Ehrlich and of Bordet. He holds that 

 lysin is not composed of two bodies, but that it is one body which is readily 

 changed into an active and passive condition. This view does not seem to 

 have found as much favor as that of EhrHch and that of Bordet. 



