PLURALITY OF COMPLEMENTS OF THE SERUM. 201 



and diatom earth, which we employed for this purpose, all proved 

 more or less unsuitable for the absorption of complement. A stronger 

 absorbent power on the other hand was exhibited by organized mate- 

 rials, thus confirming the statements of von Dungern. 1 Suspensions 

 of staphylococci, when used in sufficient quantity, were able to abstract 

 the complements quite energetically. 2 In like manner yeast powder 

 is an excellent means to deprive a serum of its complement prop- 

 erties. A separation of the complements, however, was not achieved 

 by these experiments. 



We are inclined to believe that in these cases the fixation of the 

 complements is due to physical absorption and not to definite chemi- 

 cal union. This view is the outcome of the positive results obtained 

 in the absorptions when we employed blood-cells which had been 

 mixed with suitable amboceptors, and which, according to our views, 

 were able to bind complements chemically. If blood-cells which 

 have been saturated (sensitized) with a normal immune body or 

 with one artificially produced are shaken with a certain amount 3 

 of complementing serum, it is very easy to determine that in con- 

 formity with the results of Bordet's experiments, the complement 

 properties possessed by the normal serum have in most cases com- 

 pletely disappeared with the onset of hremolysis. It was just this 

 phenomenon that led Bordet to his Unitarian conception. Yet even 

 in this absorption it is possible by means of suitable methods to 

 convince one's self of the diversity of the complements, for by making 

 the time as short as possible only those complements are absorbed 

 which possess the strongest affinity for corresponding complementophile 

 groups. Naturally experiments of this kind are difficult and require 

 considerable variation. But it is usually possible to finally devise 

 a suitable method of procedure. An interesting case studied by 

 us in this respect is the combination rabbit blood and goat serum 

 (Case II). With sufficiently rapid digestion (2 to 3 minutes at the 

 most, possibly with the aid of gentle heat) the decanted portion 

 showed a considerable loss of complements for Case IV or V, or for 

 both, without suffering any injury in the rest of its complement 



' See p 36. 



2 The same results were obtained by Wilde (Berl. klin Wochenschr. 1901, 

 No. 34) in absorption tests with anthrax, cholera, and typhoid bacteria; but 

 to conclude from this that the alexin is a simple unit, as Wilde does, is not per- 

 missible in view of our above statements. 



3 This amount must be determined separately for each case. 



