588 COLLECTED STUDIES IN IMMUNITY. 



This plurality of normal antibodies, advocated by Ehrlich in 

 a number of papers (8, 9, ii) ; is strongly combated by Bordet by 

 Buchner, who adhere to a Unitarian conception. These authors (5) 

 agree that hsemolysins and bacteriolysins are made up of two 

 parts; while they admit that the "interbody" is different, they 

 insist that only a single ferment-like substance, the "alexin, " is 

 involved in the lysis of all the various species of blood or bacterial 

 cells. 



Kraus (12) goes still further. He found that rabbit erythrocytes 

 could be protected by normal horse serum against several different 

 blood poisons, and concluded "that any given hsemolytic poison 

 acting on rabbit blood, can be paralyzed in its action by means 

 of normal horse serum." 



In view of the theoretical importance of this subject, we have 

 thought it advisable to study the question of the unity or plurality 

 of normal antibodies. In doing this we have studied experiments 

 already reported and have supplemented these with some observa- 

 tions of our own. 



So far as the hsemolysins are concerned, it has long been known 

 that many sera have the power to dissolve the blood-cells of a 

 number of other species. It is only recently, however, that we 

 have learned how easy it is to produce artificial hsemolysins by 

 immunization. The specificity of these artificial hsemolysins was 

 first demonstrated by Bordet (2), but it was not until Ehrlich 

 and Morgenroth devised elective absorption tests do) that the 

 subject became clear. This procedure is based on Ehrlich's con- 

 ception of a chemical union of erythrocytes and hsemolysin; it 

 consists in saturating a serum which contains several hsemolysins, 

 with erythrocytes of one of the species, under conditions which 

 prevent the solution of these cells. Under these circumstances 

 the erythrocytes combine with their specific hsemolysin, and 

 abstract it 'from the fluid. On centrifugirig, it is found that the 

 fluid contains only the remaining hsemolysins, and these have not 

 diminished in amount. By means of this procedure, Ehrlich and 

 Morgenroth UD demonstrated the existence of several distinct 

 specific hsemolysins in a normal serum. They showed that a normal 

 goat serum which dissolved the blood-cells of guinea-pigs and 

 rabbits, could be freed from one of these hsemolysins by treatment 

 with the corresponding blood-cells, the other hsemolysins remaining 

 unaffected. It is to be noted, however, that the hsemolysins consist 



