ANTITOXINS 29 



groups. The complete occupation of these groups 

 causes the toxicity to be entirely lost, whereas 

 partial saturation so affects the molecule that it 

 exerts a milder and different action. 



The principles of colloid chemistry have also 

 been applied to the study of the toxin-antitoxin 

 combination. Field 1 has recently tested the electri- 

 cal charge of toxins and antitoxins and finds that 

 both diphtheria and tetanus toxin and their anti- 

 toxins are electropositive, passing to the cathode 

 pole. He concludes that the combination of toxin 

 and antitoxin may perhaps represent not a true 

 chemical reaction, but the absorption of one colloid 

 by another. Ehrlich, however, still adheres to his 

 views and points out that the advocates of colloid 

 chemistry have been compelled to assume the 

 existence of specific atomic groupings very much 

 after his own ideas. He also cites van Calcar 2 who 

 claims to have separated toxin and toxon by a 

 dialyzing procedure. 



1 Field and Teague, Journ. of Exper. Medicine, Vol. ix, 1907. 



2 van Calcar, Berlin, Klin Wochenschr, 1905. 



