128 PHYSICAL CHEMISTRY IN MEDICINE. 



STEINER was the first who independently, and recogniz- 

 ing the goal toward which he was travelling, studied this 

 connection between immunity and colloidal reactions 

 experimentally. LANDSTEINER has done this more espe- 

 cially for agglutination and haemolysis, while I have 

 attempted to do it for the true toxins and their anti- 

 toxins.* 



The extensive importance of colloidal chemistry for 

 biology is by no means limited to the highly interesting 

 field of immunity. This can be shown to be true to- 

 day, however, on only a few examples. 



We are acquainted with a remarkable kind of separa- 

 tion of solid colloids through the action of surface tension, 

 an understanding of which is of importance in many 

 problems of pathology. 



The nature of these forces which evidence themselves 



* I am, of course, aware that valuable beginnings have already been 

 made to apply the facts of colloidal chemistry to the teachings of toxins 

 and antitoxins, and nothing is further from my mind than to disregard 

 the great credit which more especially BILTZ deserves in this respect. I 

 would, nevertheless, like to emphasize that my conceptions are inde- 

 pendent ones which developed gradually as such things must in 

 the course of my investigations of organic colloids. They form only 

 a special case of the analogy which I have for more than a decade 

 tried to show exists in the most varied subjects between changes in the 

 state of colloids and the processes that go on in living matter. My 

 treatment of the subject is, moreover, directed toward numerous until 

 now scarcely prized, but apparently most important, sections of the 

 problem. 



For the parallelism between the precipitation of a colloid and the 

 neutralization of a toxin by an antitoxin which I have given above, 

 the experiments of COEHN, according to whom toxin and antitoxin 

 wander toward the same side in the electric current, are of no importance, 

 as I have been able to show in my unequivocal investigations. 



