166 



ANAPHYLAXIS IN ITS RELATION TO DISEASE 



usually from eight to twelve days, we now find that symptoms ap- 

 pear after from four to seven days. Reactions of this order v. Pirquet 



Days^l ( 8 



FIG. 2 

 15 



I 2 ! 



Second Injection of 

 Horse Serum 



Incubation Sickness 



Reaction 



Diagram representing the interaction between horse serum and the corresponding ergin in rela- 

 tion to the development of serum sickness and the occurrence of an immediate reaction. (Taken 

 from v. Pirquet.) 



Fm. 



ef Serum 

 incubation 

 period 



Diagram representing the interaction between 

 horse serum and the corresponding ergin in 

 relation to the occurrence of a double reaction, 

 i. e., an immediate followed by a hastened reac- 

 tion. (Taken from v. Pirquet.) 



Immediate Hastened 

 Reaction Reaction 



Diagram representing the interaction be- 

 tween horse serum and the corresponding ergin 

 in relation to the occurrence of a hastened 

 reaction. Note the greater depth of the anti- 

 body fraction as compared with the preceding 

 figure. (Taken from v. Pirquet.) 



speaks of as hastened reactions. They are readily accounted for if 

 we remember that a cell which has once been stimulated to active 

 antibody formation (sc., liberation) will subsequently respond to 



