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On the Abmrption of Agglutinin by Bacteria and tlie Application 

 • of Pliysico-chemical Laws thereto* 



By GEOitGES Dreyer, M.A., M.D., Professor of Pathology iu the University 

 of Oxford, and J. Sholto C. Douglas, M.A., B.M., Philip Walker 

 Student in Pathology in the University of Oxford, formerly Eadclitte 

 Travelling Fellow. 



(Communicated by Prof. F. Gotch, F.R.S. Received Novemher 16, 1909,— Read 



January 20, 1910.) 



(From the Department of Pathology, University of Oxford.) 



Eisenberg and Volk, in 1902, were the first to endeavour to make 

 quantitative measurements of the absorption of agglutinins by bacteria. 

 They showed that if an agglutinating serum in varying dilution was treated 

 with a constant amount of the homologous bacteria, the amount of agglutinin 

 absorbed by the bacteria was not constant. In a concentrated serum the 

 absolute amount absorbed was greater than when the same serum was 

 used after dilution, whilst, on the other hand, the relative amount 

 absorbed from the concentrated serum was less. Hitherto these experi- 

 ments have been regarded as the fundamental groundwork for the whole 

 discussion on the combination between agglutinins and bacteria. 



Arrhenius was the first who tried to apply the laws of physical chemistry 

 to the question of immunity, stating that the interaction between toxins and 

 antitoxins, explained by Ehrlich as complex, was in reality relatively simple. 

 He stated that the combination of a toxin with its antitoxin resembled 

 that of a weak acid — boracic for example — with ammonia, and that the 

 combinations into which the bacterial toxins entered could be explained by 

 the simple laws holding good in the interactions of simple chemical 

 compounds, and without having recourse to the very complicated structures 

 assigned by Ehrlich to diphtheria toxin or tetanus toxin, etc. These theoi-ies 

 were mainly based on experiments carried out by Madsen. Arrhenius, from 

 the beginning, has considered the absorption of an agglutinin by its corre- 

 sponding bacteria as being the most simple one in the domain of immunity, 

 and as being entirely different to the interaction between toxins and their 

 antitoxins. 



* The experiments in this paper were partly carried out in the University Laboratory 

 for Medical Bacteriology, Copenhagen, and we wish to expre.«s our gratitude to Prof. 

 Salomonsen, the Director of that laboratory, for the great facilities he always granted us 

 while we woi ked there. 



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