86 IMMUNITY AND ANAPHYLAXIS 



greatest importance from the biologic point of view as well 

 as from the point of view of evolution of pathologic states. 



When antibodies form with their antigens soluble com- 

 pounds, the appearance of antibodies in excess coincides 

 with the cure. But in all the other cases when insoluble 

 compounds are formed, the appearance of antibodies in 

 excess always coincides with the beginning of the disease 

 period or, in other words, with the first appreciable patho- 

 logic symptoms. 



Up to the present we have had no idea of considering these 

 reactions together and in detail. There is, to be sure, a 

 theory (Ehrlich) to explain the origin of the pathologic 

 state or the recovery in diseases caused by the true toxins 

 (diphtheria and tetanus). It was assumed generally that 

 in the other infectious diseases the different aspects of the 

 pathologic state were caused by the combination of differ- 

 ent bacteria and by exo- and endotoxins produced in the 

 organism by these bacteria without attempting to explain 

 the mechanism of the reactions. After Ch. Richet, several 

 theories were formulated to explain the nature and the 

 mechanism of anaphylactic reactions but without attempt- 

 ing to explain the exact nature of the origin of these reactions. 



And although clinicians have, at one time or another, 

 called attention to "anaphylactic syndromes" in some infec- 

 tious diseases (Ivanoff in malaria) or to " anaphylactic crises," 

 following the injection of certain drugs (iodine, antipyrin, 

 arsenobenzene), the true students of anaphylaxis could see 

 only superficial or accidental analogies because these ana- 

 phylactic crises were not produced under the same conditions 

 as in their experiments. 



But we have seen that immunizing or anaphylactic reac- 

 tions with production of antibodies can be provoked only 

 by colloids and that crystalloids never cause analogous 

 reactions, because an antigenic albumin loses its antigenic 

 properties at the time when it ceases to be a colloid, that is 

 to say, when it is transformed into free amino-acids. The 

 nature of all these reactions ought thus to be sought in 

 the colloidal state of antigens and it is only by attempting 

 to analyze the physicochemical properties of colloids as 



