200 



COLLECTED STUDIES IN IMMUNITY. 



TABLE III. 

 HALF AN HOUR'S HEATING OF THE GOAT SERUM TO 50 C. 



difference in the diminution suffered by complement V and that 

 suffered by complement III. This is so marked that merely a com- 

 bination of the above three experiments already furnishes positive 

 proof that the complement actions in III, IV, and V proceed inde- 

 pendently of one another, and are effected by three different comple- 

 ments. 



But against this method of proof the objection might be made 

 that in the end we may still be dealing with simple [einheitlich] com- 

 plements and that the results of the experiments mentioned do not 

 necessarily indicate a plurality of complements. It could be assumed 

 that the view we have expressed concerning the plurality of the 

 complements was true only in a certain restricted sense. Thus it 

 would be possible that the complements possessed but one hapto- 

 phore group, but a plurality of zymotoxic groups of which one effected 

 the damaging action in any individual case. It could then easily 

 be imagined that the various zymotoxic groups differ from one another 

 in their behavior toward chemic or thermic influences, so that per- 

 haps one was injured by papain, and another by an alkali. In order 

 to decide this possibility either one way or another it seemed advis- 

 able to undertake absorption experiments. In case of a simple 

 complement with different zymotoxic groups, the complement would 

 be absorbed as a unit, whereas in the other case, differences such 

 as we have already observed on heating, etc., would be expected to 

 occur. 



Because of the great significance of obsorption, we regard these 

 experiments as particularly valuable. Our first experiments were 

 made to see if the complements, like so many bodies known to chem- 

 istry would adhere to granular substances of various kinds by virtue 

 of surface attraction.^ Bone charcoal, skin powder, lycopodium, 



