JOINT ACTION OF SEVERAL AMBOCEPTORS. 617 



which appeared clearly to indicate the direct union of amboceptor 

 and complement is not at all sufficient to overthrow the ambo- 

 ceptor theory. Attacking our interpretation of a phenomenon 

 which played an important role in proving the existence of direct 

 relations between amboceptor and complement, Bordet and Gay 1 

 in a recent paper, report an experiment which they believe con- 

 troverts our view. Going still further, these authors conclude that 

 the amboceptor theory must be abandoned as fallacious. We fail 

 to see the force of this conclusion. For even if the proof adduced 

 by Bordet and Gay in this single instance were accepted as irre- 

 futable, it would only show that the direct demonstration of the 

 amboceptor thoery is impossible. The authors have not brought 

 forward a single fact which contradicts the amboceptor theory. 

 If, then, in the following pages we take up at length the observa- 

 tions of Bordet and Gay, it is not because we consider it necessary 

 to renew the old discussion " amboceptor or substance sensibilatrice?" 

 but merely because of the great interest of the observations. Further- 

 more the interpretation given by the authors is so peculiar that it 

 demands further analysis. 



The case discussed by Bordet and Gay deals with a combina- 

 tion previously described by Ehrlich and Sachs, 2 namely haemolysis 

 of guinea-pig blood through the combined action of inactive ox 

 serum and active horse serum. Ehrlich and Sachs had found that 

 guinea-pig erythrocytes, which can be dissolved by a mixture of 

 inactive ox serum and horse serum, remain intact if they are first 

 treated with inactive ox serum, and then, after removing the ox 

 serum, are digested with horse serum. This showed that the con- 

 stituent of ox serum has not been bound by the blood cells. It 

 was to be assumed that this constituent represented the amboceptor, 

 and Ehrlich and Sachs therefore rightly concluded that in this 

 case the amboceptor had not been bound by the blood-cells, that 

 it reacted with the cell only after the amboceptor and complement 

 had combined. The same combination was subsequently studied 



1 Bordet et Gay, Annales de 1'Institut Pasteur, No. 6, Vol. XX, 1906. 

 2 Erhlich and Sachs, Berliner klin. Wochenschr. No. 21, 1902. See also 

 this volume, page 209. 



