IMMUNITY. 235 



is large enough, there could of course be enough present in the 

 diluted serum to kill as many bacteria as were killed by the 

 serum before dilution. 



2. Partial bacteriolysis would follow when there were fewer 

 amboceptors present in the serum than the bacteria introduced 

 and when at the same time there were. any amboceptor-com- 

 plements present. 



The extent of bacteriolysis upon dilution would depend 

 upon the number of amboceptor-complements present orig- 

 inally. 



3. No bacteriolysis could take place if the free amboceptors 

 were equal in number to the bacteria introduced, or if they 

 were in excess of this number, either in the undiluted or the 

 diluted serum. 



In the above discussion it is assumed that the two bodies 

 concerned the amboceptor and the complement of Ehrlich, 

 the sensibilisatrice and the alexin of Bordet are capable of 

 uniting and do actually unite independently of the presence of 

 bacteria or of other cells. But Bordet* nevertheless published 

 a series of investigations tending to show that the experiments 

 of Ehrlich and Sachs, which constitute the chief evidence in 

 favor of this view, are capable of quite a different interpreta- 

 tion from this, and that this interpretation is, in fact, not justi- 

 fiable from the results of the experiments which consisted in the 

 demonstration of the fact, not denied by Bordet, that ox serum 

 will produce cytolysis only when the serum has in it ambocep- 

 tors and complements simultaneously. It is not possible, as in 

 some other cases, to produce cytolysis by sensitizing cells with 

 ox amboceptors that is, with heated ox serum and, after 

 washing these sensitized cells, adding complement that is, 

 fresh serum. Cytolysis with- ox serum takes place only when 



*BORDET, JULES, and GAY, FREDERICK P. Sur les relations des sensibil- 

 isatrices avec 1'alexine. Ann. de Vlnst. Past., t. 20, No. 6, p. 267-498. Paris, 

 June 25, 1906. 



