THE COMPOUND H^MOLYSINS 257 



antiserum, the other with alexin from goats but not with 

 the antiserum used. Evidently this proof is without 

 validity. This is now conceded by Ehrlich, who believes, 

 however, that other proofs are still valid. 1 



Another remark of Bordet touches the side-chain theory 

 of Ehrlich. Ehrlich conceives the formation of antibodies 

 in the following manner : If a foreign substance is injected 

 into the body of an animal, it may be " anchored " to some 

 cells in the tissues of the animal. A chemical affinity 

 localised on a " receptor " of this cell is thereafter bound, 

 and hence the cell is hindered in one of its functions. The 

 cell then produces a new "receptor" to fill the place of 

 that seized by the foreign substance. " According to a law 

 of Weigert's, the regeneration does not only compensate 

 the defect, but overcompensates it." (This so-called 

 " law" has no standing whatever.) The excess of recep- 

 tors thus produced is given off to the blood and forms 

 the antitoxin. In our case, therefore, the immune-body, 

 according to Ehrlich, is a receptor which is able to bind 

 an erythrocyte. This receptor is called amboceptor, be- 

 cause it may even bind a molecule of alexin at the 

 same time as the erythrocyte. Now, we have seen that 

 the immune-bodies are probably not bound by the erythro- 

 cytes, but only absorbed by them. Therefore, in its old 

 formulation, the side-chain theory probably has no appli- 

 cation to this special case. Bordet, on the other hand, 

 accepts the theory of a binding process like that by which 

 dyes are bound to fibre. He, therefore, seeks another 

 proof that the theory of Ehrlich, as it is used, cannot be 

 correct. To explain the action of antisera Morgenroth 



1 Ehrlich and Sachs: Berl klin. Wochenschrift> Nos. 19 and 20 (1905). 

 s 



