VACCINES IN PROPHYLAXIS OF DISEASE 233 



dominal wall, in the interscapular region, or at 

 the insertion of the deltoid muscle using the 

 same careful asepsis as for any hypodermic in- 

 jection. 



The interval between doses is usually one or 

 two days, a convenient plan being to give three 

 doses per week. 



Duration of Treatment The duration of the 

 prophylactic treatment should, on the average, 

 consume from four to six weeks. In the great 

 majority of cases that have been reported, reac- 

 tions from the vaccine have not been noted and 

 it is possible to proceed with the immunization 

 at the intervals stated above. If, however, 

 severe reactions are encountered, the immuni- 

 zation should be continued and completed, 

 using longer intervals between doses. 



PERIODS OF HAY FEVER 



In the United States, hay fever appears at 

 two distinct periods of the year one, beginning 

 about the last week in May and continuing until 

 the second week in July (the so-called "rose 

 cold") ; the other (known as the American form 

 of hay fever), commences about the second week 

 in August and continues until the first week in 

 October. The spring variety is caused by tho 



