THE PHENOMENON OF AGGLUTINATION 245 



Here we have an inhibition zone in the tubes containing the 

 highest concentrations, accurately analogous to the previously dis- 

 cussed proagglutinoid zone. It is a phenomenon similar also to the 

 inhibition zones noticed in precipitin reactions and observed, though 

 by a different technique, in bacteriolytic phenomena discussed in an- 

 other place in connection with the Neisser-Wechsberg notion of com- 

 plement-deviation or "Komplement Ablenkung." It seems to be a 

 universal fact governing the union of colloidal substances, that defi- 

 nite quantitative proportions must be maintained in order to lead 

 to reaction, this being, possibly, explicable on the basis that actual 

 union can take place only after disturbance of the electrical balance 

 which keeps the particles apart. These reactions will be found more 

 accurately discussed in another place. Whatever the mechanisms 

 may be, however, these and similar experiments have seemed to 

 render unnecessary and unlikely the assumption of proagglutinoids, 

 proprecipitoids, etc., to explain the inhibition zones so frequently 

 observed in all reactions of this kind. 



A peculiar observation, which does not coincide with the above 

 interpretation of these phenomena, and the significance of which is 

 indeed doubtful, is one which Friedberger 73 made in researches in 

 which he confirmed the work of Bordet on the absence of agglutina- 

 tion in a salt-free environment. He found that not only the addition 

 of various salts would bring about agglutination under such condi- 

 tions, but that organic substances such as dextrose and asparagin 

 could be substituted for salts and had similar agglutinating effect 

 although higher concentrations of these than of the salts were re- 

 quired. Were these substances at all dissociable it might be pos- 

 sible that they acted by a mechanism identical with that of the salts 

 but since such substances as dextrose either do not dissociate at all or 

 do so to an infinitesimal degree only there does not seem any pos- 

 sibility of reconciling these results with Bordet's theory. 



73 Friedberger. Centralbl. f. Bakt., 30, 1901. 



