574 COLLECTED STUDIES IN IMMUNITY 



tion that the antiamboceptor acts only in "protective" experiments, 

 but is unable to act on amboceptor already anchored by the blood- 

 cells. In order to orientate ourselves concerning this last question, we 

 would of course begin by using an excess of antiamboceptor, expecting 

 very naturally, if the antiamboceptor exerts any influence whatever 

 on the anchored amboceptor, that this influence will most likely 

 become manifest with large amounts of antiamboceptor. Further- 

 more, it can then happen that the conditions obtaining are those of 

 the zone in which the curative action obtained with smaller doses 

 is concealed, owing to the excess of antiamboceptor. This may 

 perhaps account for Morgenroth's negative findings; 1 the antiambo- 

 ceptor serum employed by us was also used by that author. 



The demonstration of the fact that the antiamboceptors pro- 

 duced by immunization are usuall}?- directed against the complemento- 

 phile groups calls for a correction of certain deductions based on 

 our earlier conception of antiamboceptors as being directed against 

 the cytophile group. We must therefore concede that Eordet is 

 correct when he refuses to accept our method of differentiating partial 

 amboceptors by means of antiamboceptors, a method which we pub- 

 lished in the Sixth Communication on Hsemolysins. 2 Our experi- 

 ments at that time dealt with an amboceptor of an immune serum 

 derived from a rabbit by treatment with ox blood. This amboceptor 

 could be complemented either with guinea-pig serum or goat serum. In 

 complementing with goat serum so much more amboceptor is necessary 

 that the absence of the antiamboceptors' action must be ascribed to 

 the antiantilytic action of the normal amboceptors present. But 

 this correction does not signify that the conclusion as to the plurality 

 of the amboceptors must be abandoned. On the contrary this con- 

 clusion is confirmed by so many weighty arguments of a different kind 

 that the existence of partial amboceptors must now be classed as one of 

 the facts in immunity. We need only call attention to a point con- 

 tained in our Sixth Communication, namely, that by mutual elective 

 absorption we have shown that immunization of animals with ox 

 blood results in the formation of two fractions of amboceptors, one 

 of which acts only on ox blood, the other also on goat blood; and 

 that immunization with goat blood has exactly analogous reverse 



1 J. Morgenroth, Deflection of Complement by Means of Haemolytic Ambo- 

 eeptors. Centralblatt Bact. 1904, Vol. 35, No. 4. 



2 Ehrlich and Morgenroth. See page 88. 



