124 C. C. WARDEN, J. T. CONNELL AND L. E. HOLLY 



groups of body cells which may contam the missing substances 

 upon their surfaces. There is considerable evidence pointing 

 to the fact that toxins and antigens need not act directly on the 

 cells but through the medium of the fluids bathing them. The 

 substances primarily adsorbed, when regained gradually and in 

 excess from the cells we regard as specific antibody. 



The specific fat antigen complex of a cell may be one which 

 in its particulate character may produce poor or ready response 

 on the part of the body fluids, the result being inferior or strong 

 antibody, as for instance Streptococcus and V. cholerae; while on 

 the other hand the definite colloidal size of the antigen particle 

 may be necessary to powerful antibody production, for example 

 the C. diphtheriae; and again the colloidal dispersion of the 

 antigen may be variable and still yield all antibodies from the 

 agglutinins at one extreme to antitoxin at the other, as with 

 the B. megatherium. It is conceivable also that the fluids and 

 cells of the body respond better to some fat complexes than to 

 others, irrespective of colloidal arrangement. At best poor 

 antibodies result from attempted immunizations of laboratory 

 animals with the bodies of streptococci, and the same is true 

 with the artificial antigen and with the true streptococcus 

 hemolysin, but considering the extraordinary colloidal richness 

 of mammalian fluids and cells this idea does not seem so tangible 

 as another which is, briefly, that the antigenic complexes of 

 these microorganisms have not up to the present been employed 

 in a proper colloidal form, and we are inclined to think that 

 further study on the fluid media in which the bacteria are grown 

 will throw light on the obscure problem. 



A necessary coroUary to these principles is that all antigen- 

 antibody reactions, from agglutination and precipitation through 

 complement fixation to toxin-antitoxin aggregates, are but 

 phases of the same phenomenon acting from one extreme of the 

 colloidal realm to the other, and that all phases must be possible 

 with all cell antigens if only the proper colloidal state can be 

 found. Dean^^ showed that complement fixation and precipi- 



'' Lancet, 1918, 1, 45. 



