H&MOLYSINS. 37 



These points have only very recently bean brought 

 out by Eisenberg and Kraus, and by the author. 



This agglutination then is a chemical combina- 

 tion between the agglutinating substance of the 

 serum and the agglutinable substance of the red 

 cell or bacterium and it proceeds in definite chem- 

 ical proportions. The chemical and physical as- 

 pects of the process itself are still the subject of 

 various theories. These I shall not discuss here, 

 as they lack experimental support. The relation 

 of the agglutinins to the precipitins is still ob- 

 scure, so that I shall not venture an opinion on the 

 subject. 



Agglutinoids. Agglutinins which have lost their 

 agglutinophore group through the action of acids, 

 etc., but which still possess their haptophore 

 group, are called agglntinoids, just as toxins which 

 have lost their toxophore group are called toxoids. 

 Such agglutinoids, then, may still combine with 

 the blood-cells or bacteria without, however, being 

 able to produce any clumping or agglutination. 



Purpose of Agglutination. It is not yet clear 

 what the purpose of the agglutinating function is. 

 Gruber, the first to thoroughly study and appreci- 

 ate the bacterial agglutinins, assumes that the 

 process injures the affected cell, preparing it for 

 solution and destruction. After numerous experi- 

 ments I have not been able to convince myself of 

 any damaging influence of the agglutinins on the 

 affected cell, be this blood-cell or bacterium, and 



