650 COLLECTED STUDIES IN IMMUNITY. 



the antiamboceptors produced by immunization has undergone 

 profound alterations within the past few years, thanks to the funda- 

 mental researches made by Bordet. These investigations were fully 

 confirmed as to fact by Ehrlich and Sachs/ and by Muir and Brown- 

 ing. 2 We must, therefore, assume that the antiamboceptors are 

 usually antibodies of the complementophile group, and in this respect 

 must regard Bordet's findings as a most conclusive argument in 

 favor of the amboceptor theory. Bordet's strongest point consists of 

 the fact that it is possible, by immunizing with normal serum, to 

 produce antiamboceptors which act against all the amboceptors 

 (both normal and immune) of the species whose serum was used 

 for immunization. But just this circumstance should arouse skepti- 

 cism and make us question whether perhaps the antiamboceptor 

 effect is not merely apparent, and counterfeited by the complement- 

 binding power of albumin laden with antibody. The experimental 

 analysis of this case is far more easy than the differentiation of the 

 anti-complements. In true antiamboceptors the point of attack 

 is a different one, being confined, as already said, to the comple- 

 mentophile group of the amboceptor. Nevertheless, the differen- 

 tiation of the antiamboceptors is not as simple as was originally 

 stated in Ehrlich and Morgenroth's communications. Suppose, for 

 example, that we mix amboceptor and antiamboceptor, add blood- 

 cells, centrifuge, wash the sediment thoroughly, and find, after the 

 addition of complement, that haBmolysis does not take place. A 

 little consideration will show that such a result permits of two 

 interpretations. It may be clue to an antiamboceptor; it may, 

 however, be due to the complement-deflecting power exerted by an 

 albuminous precipitate possibly carried down with the blood-cells 

 laden with amboceptor. It is important to bear in mind that the 

 serum containing the amboceptors also contains albumin antigens, 

 and that the antiamboceptor serum contains albumin antibodies. 

 We fully agree, therefore, with the statement made by Pfeiffer and 



1 Ehrlich and Sachs, Ueber den Mechanismus der Antiamboceptorwirkung. 

 See page 561. 



2 Muir and Browning, On the Properties of Anti-immune bodies and comple- 

 mentoids. Journal of Hygiene, 1906, Vol. VI, No. 1. 



NOTE. Those wishing to follow the historical development of the subject 

 will find this discussed in the paper by Ehrlich and Sachs already alluded to. 

 In this, too, mention will be found of the investigations of Pfeiffer and Fried- 

 berger, which may be regarded as precursors of Bordet's observations. 



