176 Dreyer and Douglas. Velocity of Reaction hi [Nov. 16, 



As we know from experiments of Morgenrotli that it takes several hours 

 at I'oom temperature before eqviilibrium is reached, when a diphtheria 

 antitoxin acts on a diphtheria toxin, there is now no excuse for contrasting 

 " the rapid reaction " in the one case (absorption of agglutinin) with " the 

 slow reaction " in the other (neutralisation of diphtheria toxin). To draw 

 such a distinction between the interactions of these different antigens and 

 antibodies is unjustifiable, since in both instances the reaction is rather a 

 slow one. As Arrlienius has used " the rapid reaction " in the case of the 

 absorption of agglutinins by bacteria to disprove Bordet's theory that the 

 agglutinins were adsorbed by the bacteria in the same way as a dye by 

 a fibre, where the reaction is a slow one, it was of interest to make 

 experiments which would enable one to compare the velocity of reaction 

 in adsorption processes with that found by us in the absorption of agglutinin 

 by bacteria. For this purpose we have investigated the adsorption of 

 agglutinins, trypsin, and sulphuric acid by animal cliarcoal. 



From Experiments 5, 6, 7, 8 (Tables VII, VIII, IX, X), in which 

 agglutinin is acted on by charcoal, it will be seen that the amount of 

 agglutinin left free in the supernatant fluid lessens as the time during 

 which the adsorption is allowed to proceed increases. This observation 

 is in entire agreement with those made by previous observers, showing that 

 in adsorption processes it takes a long time before equilibrium is reached. 



Comparing together Experiments 5 and 6, it is further seen that, at the 

 same temperature, where small amounts of charcoal acted on small amounts 

 of agglutinin, the velocity of reaction is smaller than with larger amounts 

 of charcoal and larger amounts of agglutinin, within tlie limits of the 

 experiments. 



From Experiments 5, 6, 7, and 8, it icsults that the rate witli wliich the 

 adsorption of agglutinin by charcoal proceeds is markedly greater than is 

 that of the absorption of agglutinin by bacteria. lUit if we compare the 

 progress of adsorption in these experiments with that seen in Experiment 9 

 (Table XI), in whicli try])sin is treated with diarcoal, it is clear that the 

 rate of adsorption in this latter case is ever so much the greater. 



Examination of Experiments 10, 11, and 12 (Tables XII, XIII, XIV), in 

 wliich charcoal is allowed to adsorb sulphuric acid, shows that tlie (juantity 

 of acid adsorbed augments witli tlic lapse o'f time, hut docs so le.ss rapidly 

 than was the case in the otlier adsorption oxjK'iiinents (Nos. 5 to 9). Tlie 

 rate of adsorption is, in fact, aj)pr()xiiiiately the same as it was in tlie 

 absorption experiments (Nos. 1 to 4), in whicli agglutinins were jjlaced in 

 contact willi biicilli. For cxiiinplc, in I^A'pcrinicnt 4 (Tal)U! XV), the 

 percentage of agghiliniii al)S()rhed incrcas(Hl lioni 82-2 at tlio end of 



