HYPERSENSITIVENESS 577 



ai>eiit is unknown. Olliers hnvv sui>i>ostcd standarclizinji>" it by 

 skin tests on allersi'ic individuals, l)ul Ihis method lias not met with 

 favor. 



Cooke and Stull (1933) standardize pollen extracts on the basis 

 of their protein nitrogen content, while others regard total nitrogen 

 as a better criterion. Coca (1933) offers numerous objections to the 

 method of Cooke and Stull. He suggests (1934) a new definition 

 of the Noon pollen iniit and recommends that the Noon unit be 

 "the quantity of pollen extract which contains 0.00001 milligram 

 of total nitrogen." Coca says that this represents ap])roximately 

 the total N present in the exti^act of one-millionth of a gram of 

 ])ollen. 



Character of an Allergic Skin Reaction. — Positive skin reac- 

 tions to atopens are characterized by the formation, within a few 

 minutes after the test is performed, of a wheal one or more 

 centimeters in diameter. The reaction consists of a reddening of 

 the skin, which is called the flare, and the development of a 

 central blister showing one or more pseudopods. 



Recording Skin Reactions.- — In recording skin reactions some 

 individuals describe them as + to + + + + depending upon the size 

 of the wheal, number of pseudopods and the size of the area of 

 erythema. According to Berkoff (1933) others record reactions 

 as slight, moderate, marked, or very marked. Not infrequently 

 the reactions are descril)ed by measurements. Berkoff suggests 

 that a sheet of a modified celluloid called ''absolite"' or ''plas- 

 tocele" 9 by 16 cm., be ruled oft' in 1 cm. squares and that 4 eye 

 holes 1, 1.5, 2 and 3 cm. in diameter, respectively, be made and 

 used for measuring the size of the skin reaction. These holes repre- 

 sent reactions of + to + + + +, respectively, and the results are so 

 recorded. 



Treatment of Allergy. — Two types of treatment apply to all 

 forms of allergy except perhaps serum disease and these are avoid- 

 ance of the exciting agent and desensitization, respectively. Ex- 

 perience has shown that it is not always possible to employ either 

 of these forms of therai)y and that palliative measures have to be 

 used. The latter vary with the type of clinical allergy encountered. 



The promising reports of Bloom (1938) on the use of potassium 

 chloride and of Ertl (1939) on the use of histamina.se in the treat- 

 ment of allergy have not met with general confirmation. Spain, 



