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donous stock but nothing more. They are, however, enough dif- 

 ferent from each other so that we generally may easily recognize 

 the family, often the genus and occasionally even the species of 

 anemophilous pollen which is caught on atmospheric pollen 

 slides. And this is always a great help to the student of hayfever. 



Just which of the various kinds of pollen found in the air 

 aflfect a hayfever patient may be determined by what is known 

 to physicians as the skin test. The theory of the skin test is 

 based on the fact that if a person is sensitive to any particular 

 kind of pollen or other substance in such a way as to cause nasal 

 or other respiratory symptoms the same sensitization extends 

 to all parts of the body, so the customary way of performing the 

 skin test is to make the tiniest possible nicks in the skin and 

 apply to them drops of solutions extracted from the different 

 kinds of pollen to be tested. \\'hen the right extract is applied 

 the harmless-looking nick in the skin will immediately take on 

 all the characteristics of a good lusty mosquito bite, including 

 the swelling, itching and surrounding reddish irritation. The 

 test belongs to that class of physiological reactions known as 

 anaphylaxis which includes such phenomena as serum sickness 

 and anaphylactic shock, and is characterized by an explosive 

 violence out of all proportion to the quantity of the irritating 

 material applied. For this reason the test should never be at- 

 temped except by the trained practitioner with standardized 

 materials. 



After the kinds of pollen in the air have been determined 

 and which of these affect the patient, he has the choice of going 

 elsewhere when the offensive pollens appear, or else of develop- 

 ing his tolerance beforehand. This is accomplished by adminis- 

 tering a series of small but gradually increasing doses of extracts 

 prepared from the pollens to which he is susceptible and likely 

 to be exposed. In this the dosage must be carefully controlled. 

 Too little is useless but too much is dangerous, so this also 

 should be attempted only by a skilled physician. 



YOXKERS, N. Y. 



