1909.] On the Absorption of Agglutinm by Bacteria, etc. 187 



concentration of the amount of agglutinin left (B) in the fluid after 

 absorption has taken place, and with increase of the total amount of 

 agglutinin originally present (T), yet no such limit can be observed in the 

 experiments of Eisenberg and Volk on the absorption of agglutinin by 

 bacteria, or those of Morgenroth and Arrhenius on the absorption of 

 immune body by red corpuscles. 



3. That the absorption of agglutinin by bacteria must be in nature different 

 to the so-called adsorption processes, since in the latter 7i is generally found 

 to be small (c.[/. in the case of charcoal 0*25, Schmidt), while in the case of 

 bacteria and agglutinin the value of n is from f to 1. 



4. That the accordance between the observed values and those calculated 

 by the formula C = A'B" (where n = |) is as good as could be expected in 

 experiments of this kind, owing to the great difficulties in the technique. 



Having thus briefly stated the arguments brought forward by Arrhenius 

 in support of his view of the equilibria in the absorption processes of 

 agglutinin by bacteria, we shall go on to our own experiments. 



In deciding whether any such given formula offers a correct summarisation 

 of the experimental facts upon which it is based, it is of the greatest 

 importance that the experiments should be very numerous. It is no less 

 important that the experiments should cover a wide range of concentrations. 

 If these precautions are omitted, small deviations from the calculated values 

 will easily be misinterpreted as experimental errors, when in point of fact 

 they are periodical variations occurring with the utmost regularity. Now 

 one of us (G. D.) had proved, in 1904, that the interaction between Coli agglu- 

 tinin and the filtrate of old Coli culture (" toxin ") did not follow the 

 partition law C = k& given by Arrhenius, which one might expect it to do 

 if that law actually governed the combination of agglutinin with the specific 

 substance in the bacteria. In addition, it seemed probable from the experi- 

 ments of Eisenberg and Volk, and Morgenroth and Arrhenius, that periodical 

 variations between values calculated according to this formula and those 

 observed experimentally would occur. Accordingly, our own experiments 

 were designed in such a way and given such a range as to minimise the 

 likelihood that important differences such as these would be missed. 



The technique employed was in all detail the same as that already 

 described in our paper on the Velocity of Eeaction in the Absorption of Specific 

 Agglutinins by Bacteria, etc.* In the following experiments, coli and typhoid 

 sera of different strengths and age, obtained from various animals immunised 

 with different strains of bacteria, were used. Bacteria or bacterial filtrates 

 (" toxin "), homologous to the serum taken for the experiment, were always 



* P. 168, SKpra. 



