REVIEW OF BESREDKA'S STUDY. 289 



lished by Schattenfroh l that they are excreted through the urine 

 in considerable amounts. 



One reason above all has led us to believe that Besredka's views 

 required to be controverted in detail, namely, the fact that they 

 maintain the Unitarian conception that only one hsemolysin is pos- 

 sible against a given species of blood and one bacteriolysin against 

 a given species of bacterium. This conception can seriously retard 

 the development of the doctrine of immunity and especially of the 

 practical application of this doctrine. 



The recent investigations which have demonstrated the exceeding 

 multiplicity of the cell's receptors and of the amboceptors obtained 

 by immunizing with these receptors show that this study can be 

 successfully pursued along two directions. One of these consists in 

 the production of polyvalent sera by immunizing with numerous 

 strains of the same bacterial species. It may be assumed that the 

 varieties of a bacterial species contain the various receptors in very 

 varying proportions, and this is confirmed especially by Durham's 

 experiments concerning the agglutinatibility of different strains of 

 coli by specific sera. A sufficient increase of all the amboceptor 

 types in question is therefore possible only after a high degree of 

 immunization has been effected against a large number of related 

 strains. This procedure had previously been chosen by Denys and 

 van de Velde in the production of their polyvalent streptococcus 

 serum, and has recently been employed by Wassermann and Oster- 

 tag 2 for the preparation of an effective serum against hog cholera. 

 These procedures are based entirely on the experiments of Ehrlich 

 and Morgenroth, just mentioned. 



The other method of obtaining effective bactericidal sera is based 

 on the assumption that the amboceptors, according as they are de- 

 rived from different animal species, differ from one another. So far 

 as this point is concerned, we may refer to the statements of Ehrlich 

 and Morgenroth, 3 which are summed up in the sentence, "it would 

 therefore be advisable not to attempt the production of bactericidal 

 sera from a single animal species as is now customary, but to make 



1 Schattenfroh, Munch, med. Wochensch. 1901, No. 31. 



2 Wassermann and Ostertag, Monatsch. f. prakt. Thierheilk, Vol. 13, foot- 

 notes. 



3 See page 110. 



