32 PROPERTIES OF ILEMOLYTIC SERA 



ment taken up is approximately proportional to the amount 

 of immune-body ; in other cases considerable divergence is- 

 met urith. It is thus seen that the dosage of complement 

 necessary for lysis, just as in the case of immune-body,, 

 gives no indication of the amount which can be taken up ; 

 complete lysis may represent quite an early stage of the 

 total combination possible. 



THE EHRLICH PHENOMENON IN THE UNION OF 

 COMPLEMENT 



In the earlier experiments with small multiples of the 

 hsemolytic dose of immune-body it almost appeared that 

 when complement was added there was an exact neutraliza- 

 tion point in which the further addition of a dose of comple- 

 ment gave one dose free, but on using higher multiples, 

 and especially with certain samples of serum, it was found 

 that after the appearance of free complement much more 

 than a lytic dose had to be added before complete lysis 

 of the added corpuscles was obtained. It may be stated 

 as the result of a large series of experiments that the Ehrlich 

 phenomenon is always present, though sometimes, especially 

 in the case of very active sera, it may be very slight. Ex- 

 amples of the manner in which the phenomenon appears 

 are seen in the tables above. It may be stated that the 

 same features in the mode of combination of complement 

 are seen in the case both of serum receptors + their anti- 

 substances and of bacteria + the homologous immune-bodies. 

 And in the latter case it is noteworthy that we have been 

 unable to find any dissociation of complement after it has 

 combined. 



In the case of the union of immune-body with receptors 

 of red corpuscles, the Ehrlich phenomenon has been explained 

 above as being due to the reversibility of the combination, 

 but in the case of the union of complement this cannot be 

 the explanation, as the reversibility is either non-existent or 



