IMMUNITY AND ANAPHYLAXIS 85 



words, the transformation by which toxins and albumins 

 after injection become either assimilated or eliminated is 

 accomplished by a reaction of the same nature. 



It is hardly probable that an albumin, even homologous, 

 when injected into the blood or under the skin can be assimil- 

 ated without undergoing some sort of transformation and 

 the mild anaphylactic disturbances which are seen after 

 the transfusion of 100 c.c. or 200 c.c. of whole blood: chills, 

 excitement, dyspnea, peripheral pallor seem to show that 

 in this case there is no assimilation without previous trans- 

 formation. In every normal organism there is an antibody 

 in excess for homologous albumins and this antibody reacts 

 with these albumins in a way quite analogous to the reac- 

 tion of toxin with antitoxin. 



We will return later to this question which we can only 

 indicate here. For the moment it is important to recall 

 from what has preceded, that if the nature of the reactions 

 caused by antigens seems to be determined by the physico- 

 chemical properties of the colloidal state of these substances, 

 the effects of these reactions on the organism will depend 

 principally, if not exclusively, on the nature, the biologic 

 properties and the quantity of antibodies, normal or in excess. 



From the biologic point of view, we may divide the reac- 

 tions between antigen and antibodies into two great groups: 



1. Those which produce immunity alone diphtheria, 

 tetanus toxins, perhaps botulism and homologous albumins. 



2. Those which produce immunity and anaphylaxis or 

 only anaphylaxis all the other antigens, bacteria and 

 heterologous albumins. 



From the physicochemical point of view it may be said 

 that: 



1. Antigens which are exclusively immunizing form with 

 their antibodies soluble compounds. 



2. Those which are immunizing and anaphylactic or 

 exclusively anaphylactic form with their antibodies insoluble 

 compounds. 



In the first instance the antibodies in excess dissolve the 

 colloidal antigens; in the second, they precipitate and this 

 difference in the nature of the resulting compounds is of the 



