566 IMMUNOLOGY 



recognized that the June grasses are the principal causes of hay 

 fever in the early summer, while ragweed pollen is the chief 

 offender in August and September. 



Dunbar Confirmed Blackley's Work. — The confirmation of 

 Blackley's work by Dunbar in 1903 stimulated widespread interest 

 in the subject. The results of subsequent research are discussed 

 at length in the monographs of Rackemann, Coca and others. The 

 most important discoveries are summarized earlier in this chapter. 



Perennial Vasomotor Rhinitis. — In regard to perennial vaso- 

 motor rhinitis the important facts may be presented by giving a 

 resume of Rackemann 's report on 257 cases studied by him. The 

 majority of these patients were 3'oung people and 73 per cent were 

 women. In only 25 per cent did he find a history of allergy in the 

 family. Sixteen per cent of the 257 individuals presented symp- 

 toms of asthma and 7 per cent eczema along Avith those of vasomotor 

 rliinitis at the time of examination. He was able to identify the 

 ex<'iting agent in only 150 or 58 ])er cent of the 257 patients. 



Perhaps the reason that sucli a liigh ])erccntagc of his cases ap- 

 peared among young women is that cosmetics arc used so exten- 

 sively by them. He had 44 cases in which tlie exciting agent was 

 orris powder. All of these gave positive skin tests. Other investi- 

 gators have reported cases of vasomotor rhinitis due to rice flour 

 and various other substances used as cosmetics. In Rackemann 's 

 series there were thirteen patients sensitive to emanations from 

 cats, dogs, feathers, etc. In another group he places those sensi- 

 tive to something in house dust. 



In a few cases of vasomotor rhinitis there was an expression of 

 hypersensitiveness to occupational dust while in others it was due 

 to food allergy. 



In 72 cases of Rackemann 's series operations were performed 

 to clear up local lesions. Tonsillectomies seemed to benefit two out 

 of sixteen patients while four out of twenty-two were benefited 

 by the drainage of their sinuses. The straightening of the nasal 

 septae of thirty patients resulted in beneficial results to seven. 



Asthma. — The term "asthma" according to Brown (1917) is 

 used to apply specifically to that type of dyspnea characterized 

 by (1) prolonged and difficult expiration especially if the attack 

 be well developed (in the beginning of a paroxysm, however, botli 

 inspiration and expiration may appear equally difficult) ; (2) a 



