62 COLLECTED STUDIES IN IMMUNITY. 



not be surprising if we remember that normal blood serum con- 

 tains, besides the haemolysins, a number of other active substances 

 such as hsemagglutinins, bacterioagglutinins, antiferments, ferments, 

 cytotoxins, etc. ; and further, that from a normal serum which agglu- 

 tinates several species of bacteria, the corresponding agglutinin 

 can be isolated and abstracted by treating the serum with one of 

 these species (Bordet) ; and that the same holds true for hsemagglu- 

 tinins (Malkoff). We shall quite naturally come to the conclu- 

 sion that, under normal conditions of the cell's nutrition, a large 

 number of simple or complex side-chains are constantly thrust off 

 which then, either alone or in conjunction with complements simi- 

 larly thrust off, exert specific actions. Hence normal serum contains 

 an enormous number of such substances. To these, in general, we 

 give the name haptins. 



When therefore Buchner, in opposition to our views, believes 

 that the assumption of these different substances seems unreasonable, 

 we must emphasize that our conclusions are not the result of specu- 

 lation, but simply the necessary consequences of observations which 

 are not to be harmonized with the assumption of a single simple 

 alexin. It will be evident also why we have completely dropped 

 the term alexin used by Buchner. In our investigations, in all the 

 cases closely analyzed, we never found a simple substance (Buchner's 

 alexin), but always a complex hsemolysin consisting of interbody and 

 complement. This hsemolysin, as alreaady emphasized, completely 

 corresponds in its properties to the hsemolysins developed through 

 immunization. We shall therefore have to assume that also in 

 their development the normal hsemolysins correspond exactly to the 

 artificial hsemolysins. 



In regard to the latter, von Dungern has already shown, by 

 demonstrating a great disproportion between immune body and 

 complement, that these two substances are produced quite inde- 

 pendently of one another, and that they therefore probably originate 

 in different cell domains, von Dungern also showed that in the 

 extensive formation of new immune body which occurred when 

 rabbits were treated with cattle blood-cells, the corresponding com- 

 plement was not in the least increased. We ourselves have often 

 noted an analogous independence of the two components in a 

 number of normal hsemolysins. One of us will discuss this at length 

 in a subsequent paper. One interesting fact, however, we shall men- 

 tion here. 



