68 MECHANISM OF AGGLUTINATIOX, 



A year afterwards Friedberger"^ published a paper in which he 

 showed that other salts were as useful as common salt in causing 

 agglutination. He concluded that : — 



1. Agglutination does not occur in the complete absence of 



crystalline substances. 



2. Of these substances the inorganic salts are the most active 



and they differ among themselves in their activity. 



3. The rapidity of the onset of the agglutination of dialysed 



cultures depends upon the salt content of the bacterial 

 suspension. 



4. The rapidity of the onset of the agglutination of a bacterial 



emulsion depends upon its salt content. 



5. The action of salts in agglutination is not chemical. 



Thus the function of salts in general in causing agglutination 

 is emphasised. Exception must, however, be taken to the 5th 

 item, which is rather startling. Friedberger does not attempt to 

 explain the mechanism of the process, and that he cannot under- 

 stand the part played by the salts is made evident by his sweeping 

 assertion. By chemical, he means that the salts do not chemically 

 combine with the albumen of the cell, an idea which has never 

 been advanced with an}^ positiveness. Bordet, perhaps by con- 

 sidering that Kraus' precipitate did not play a part in agglutina- 

 tion, suggested the idea of an enzyme altering an albuminoid 

 constituent of the microbic cell; but beyond this inference there 

 is nothing to justify the assumption that coagulation of the cell 

 albuminoids may occur. That the bacteria simply become immo- 

 bilised is well known. Were a portion of their albuminoid matter 

 coagulated, probably something more than immobilisation would 

 ensue. Joos confirmed the fact that agglutination does not alter 

 the vitality of the bacteria. 



In a later paper Joos,t after pointing out that Fried berger's 

 researches strengthened his own former conclusions, finally pro- 



* Friedberger, Cent. f. Bakt. xxx., 330. 

 t Joos, Cent. f. Bakt. 1 Abt. xxx., 853. 



