VACCINES IN PROPHYLAXIS OF DISEASE 235 



the progressive dosage and to allow a sufficient 

 interval between the doses. 



Reaction The doses of Pollen Vaccine, as 

 prepared in our laboratories for the prophy- 

 lactic treatment of hay fever, have been so ad- 

 justed as to avoid severe reactions. Well- 

 marked reactions, characterized by an exag- 

 geration of the usual symptoms of hay fever 

 (sneezing, lacrimation, itching of the eyes, 

 cough, dyspnea in asthmatic subjects, and 

 sometimes edema and urticaria), which have 

 been met with by some workers, have occurred 

 only as the result of too large an initial dose. 



According to Koessler, only a very small 

 number of patients show any local reaction at 

 the site of injection, consisting of a slight red- 

 dish-colored tumefaction. 



Immunity The immunity does not last 

 equally long in all patients. According to Free- 

 man, the immunity acquired from the prophylac- 

 tic inoculations seems to last at least one year 

 after the treatment has been discontinued. 

 Koessler observed that the susceptibility of pa- 

 tients who received the prophylactic inocula- 

 tions before the onset of the hay fever season 

 returned during the fall and winter; so that, 



