178 NEISSER-WECHSBERG PHENOMENON IN HAEMOLYSIS 



washed, and treated with more normal serum, haemolysis took 

 place. It thus appears that, in the first instance, the corpuscles 

 took up only those amboceptors which had no attached comple- 

 ment. It would appear, therefore, that amboceptor may unite 

 with complement whilst free, and that when it has done so its 

 affinity for the corpuscle is diminished. This is one of the 

 conditions which Neisser and Wechsberg imagined, and which 

 they showed would make the phenomenon of deviation even more 

 marked. And Meakins shows, though not in a very clear way, 

 that it does actually take place with corpuscles that are well 

 washed. The reason why it does not take place under ordinary 

 circumstances is explicable on the basis of Gengou's reaction. 



But this theory cannot be regarded as entirely satisfactory. It 

 assumes, in the first place, a direct union between complement 

 and amboceptor before the latter has united with the cell or 

 bacterium, and of this there is no definite evidence apart from 

 this phenomenon. Ehrlich, it is true, supposes a feeble union 

 between the two which easily dissociates, even at low temperatures, 

 so that a cell which has been placed in contact with a mixture of 

 the two at o will become saturated with amboceptor devoid of 

 complement. But this appears to be a fatal objection to Neisser 

 and Wechsberg's explanation ; for if the hypothetical amboceptor - 

 complement combination dissociates readily at a low temperature, 

 it should do so still more at a high one. Now the receptor- 

 amboceptor-complement will not dissociate, or only to a very 

 slight extent, since lytic action will at once commence. It follows 

 that the amboceptor-complement molecules will gradually all 

 dissociate, and the complements will sooner or later find their 

 way to the anchored amboceptors, and there remain. The process 

 may be delayed, but after a time all the attached amboceptors 

 will become complemented. And if, as seems implied in Ehrlich's 

 writings, the affinity of the complementophile group becomes 

 raised in virtue of the union of the cytophile group, with its 

 appropriate receptor, this process will take place all the more 

 quickly. 



It appears much more likely that the Neisser- Wechsberg 

 phenomenon is an example of a reaction of a kind which has 

 already attracted much attention, and which may possibly modify 

 fundamentally our views on the antibodies, toxins, etc. They will 

 be referred to again when we deal with the agglutinins, and it is 

 sufficient to say here that in other cases, when there is no question 



