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Dr. G. Dreyer and Mr. J. S. C. Douglas. [Nov. 16, 



Before describing our own results, we shall briefly mention Arrheuius' 

 view as to the absorption of agglutinins by bacteria. Taking the experiments 

 of Eisenberg and Volk, he showed that there existed a relation between the 

 q^uantity of absorbed agglutinin (C) and the free agglutinin (B), as expressed 

 by the formula C = ZB^, where k is a constant. 



" The physical interpretation of the above formula is very simple. It 

 states that the agglutinin molecules are divided between two solvents, the 

 bacterial cells and the surrounding medium, and that of two molecules of 

 the free agglutinin are formed three molecules of the absorbed agglutinin " 

 (Arrhenius). This is a special case of the Guldberg-Waage law of chemical 

 mass action, and is comparable to the distribution of benzoic acid in the 

 two different solvents, water and benzene, where the concentration of 

 the aqueous solution (Ca) is related to tlie concentration of the benzene 

 solution (Cj), according to the formula = kCi,-, as has been shown by 

 Nernst. 



Later on, Arrhenius changed his formula from C = kB^ to C = A-B", as it 

 was found from a series of preliminary experiments carried out by one of us 

 (G. D.), but hitherto not published, that not only the constant k, but also 

 the exponent ii varied in different experiments, this variation in the 

 exponent n changing the interpretation of the formula from a simple to 

 an elaborate one. 



Arrhenius states in his book on Immuno-Chemistry that v, in the case of 

 the absorption of agglutinin by bacteria, always falls near unity, whicli is 

 certainly not the case, and he also states that, as ?i may even be greater 

 than unity, its value has a certain theoretical significance, as an aid in 

 deciding the nature of the process involved in the absorption of the 

 agglutinin. 



In support of his theory dealing witli equilibria in absorption processes, 

 Arrhenius brings forward the following principal arguments : — 



1. That the absorption of agglutinin by bacteria cannot bo analogous to 

 the so-called adsorption of dissolved substances by charcoal, or of colouring 

 matter by a filu'c (Bordet, Biltz), because the velocity of tlie reaction in tlie 

 former case is very great, equilibrium being reached in less than five minutes 

 at 0° C. (Eisenberg and Volk), wliereas, in the case of adsorption by charcoal 

 or by a fibre, the process may be incomplete- even after several days at the 

 temperature of the room (Bordet, Hedin, etc.). 



2. Tliat the absorption of agglutinin by bacteria caniu)t be a chemical 

 combination in the usual sense, unless it should be a very higldy dissociable 

 one, because, even accepting a high degree of dissociation, the fraction of 

 agglutinin fixed ((J) sliould iiicrea.se to a limit vaku; with increasing 



