130 Active Immunization to Hay Fever [March, 



that there may be, in some cases, a general susceptibility to all 

 pollen, so that only when a given reaction is marked is it possible 

 to conclude which pollen is specifically causative of hay fever in a 

 particular case. To be sure that no other factor than the pollen 

 causes the reaction in a given instance, it is advisable to establish a 

 negative control by simultaneous vaccination of another patient. 

 No swelling should occur in the control. 



Theoretical considerations. According to Rosenau and An- 

 derson ( 10) , Otto, (11), and others, if on the seventh, eighth or ninth 

 day after the first injection, a massive dose of antigen is injected 

 into the experimental animal, Symptoms of anaphylaxis do not 

 occur with a dose of antigen on the twelfth day. This refractory 

 condition, so produced, is called awfi-anaphylaxis. This same ani- 

 mal will, twenty to thirty days later, become slightly sensitive to 

 antigen, the Symptoms being mild, fatal reactions rarely occurring. 

 The reason for this refractory condition, so produced, was revealed 

 by the researches of Neufeld and Dold (12), Kraus (13), Ritz and 

 Sachs (i4),Izar (15), Friedberger andMita (16), Zinsser (17) and 

 Bordet (18), who, working on the quantities of antigen, ambocep- 

 tor, and alexin, which are most favorable for the production of 

 anaphylatoxin in vitro, found that large proportions of anitgen as 

 compared with the other factors inhibited the production of ana- 

 phylatoxin. They also showed that an excess of amboceptor pro- 

 duced the same result. In view of these facts, they concluded 

 that the great concentration of antigen in the blood of the re- 

 fractory animal inhibited the production of sufficient anaphylatoxin 

 to cause Symptoms. 



Zinsser and Dwyer (19), working with typhoid anaphylatoxin, 

 showed that guinea pigs treated with sub-lethal doses of anaphyla- 

 toxin, developed a tolerance which enabled them to resist one and 

 one-half to two units of the poison, the tolerance developing within 

 three days and lasting to a slight degree for as long as two months. 



From the foregoing facts, it should be possible to treat patients 

 suffering with pollinosis by one of f our methods : 



I. By injecting a dose of pollen extract just before the hay 

 fever time and repeating the procedure in twenty to thirty days. 



2. By injecting a large quantity of immune serum during the 

 attack. 



