326 PROTEIN POISONS 



of the antigen. This is explained by Friedberger by sup- 

 posing that the small dose uses up a part of the sessile 

 receptors, and that there are not enough left to induce 

 anaphylactic shock when another injection is made. In 

 short, he concludes: "In every case antianaphylaxis is 

 nothing more than anaphylaxis refraeta dosi." Passive 

 anaphylaxis is explained by Friedberger by supposing that 

 the free receptors in the blood of an anaphylactized animal 

 become, on injection into a fresh animal, anchored to the 

 cells, thus forming fixed or sessile receptors. This is Fried- 

 berger's theory. It is clean cut and clearly stated by its 

 distinguished author, but at present it has no support, 

 and is clearly out of harmony with known facts, some of 

 the most important of which have been discovered by the 

 researches of its own author. It was an attempt to make 

 the facts of anaphylaxis fit Ehrlich's theory of the action 

 of toxins and the production of toxin immunity, while 

 the trend of later research is to show that the two sets of 

 phenomena have but little in common. Friedberger's 

 theory would make the action of sensitizers, such as serum 

 albumin, egg-white, edestin, bacterial proteins, etc., identical 

 with that of diphtheria and tetanus toxin, abrin, ricin, 

 the venoms, etc. There is nothing in the theory about the 

 development of the proteolytic ferments, and the liberation 

 of a protein poison by the parenteral digestion of the sensi- 

 tizer on reinjection. If we read his works with correct 

 interpretation, Friedberger has abandoned his own theory 

 largely, if not wholly. Indeed, in Contribution VI, 1 Fried- 

 berger plainly discards his own theory. 



According to Friedberger's theory all sensitizers act like 

 the toxins; although at first only mildly toxic, they become 

 more so by developing the receptors, and thus rendering 

 the animal more susceptible. It is in a way proper for 

 Friedberger to speak of anaphylaxis as a "protein-anti- 

 protein" reaction. Friedberger calls the sensitizer an 

 antigen and the substance developed in the animal an 



1 Zeitsch. f. Immunitatsforschung, 1910, vi, 179. 



