136 FUNGUS DISEASES OF MAN AND ANIMALS 



coccidioidin, and these reactions have so far not been satisfactorily 

 explained. 



Other mycotic antigens are less specific or have had less extensive 

 use than coccidioidin. Histoplasmin has been prepared by a number 

 of investigators. Palmer/° using histoplasmin prepared from the 

 synthetic broth mentioned above, reported that in student nurses 

 tested there was a very high correlation between positive histoplasmin 

 skin reactions and pulmonary calcification, and suggested that Histo- 

 plasma might be responsible for non-tuberculous calcification. It 

 is known, however, that this histoplasmin gives cross reactions with 

 other mycoses. ^^ 



A skin-testing antigen prepared from Aspergillus jumigatus at the 

 National Institute of Health and used in testing experimentally in- 

 fected guinea pigs had a primary irritating effect and gave non- 

 specific reactions. 



The use of a skin-testing antigen in the diagnosis of a mycosis has 

 definite limitations which are not always recognized. A positive re- 

 action may be due to a non-specific factor common to several patho- 

 genic fungi; or, if it is a true specific reaction, the person may have 

 been sensitized by a previous exposure to the fungus quite unrelated 

 to the condition in "^'hich a diagnosis is sought. Skin sensitivity, 

 once it is acquired, persists for many years and perhaps for life. 



Asthma. Considerable attention has been directed toward mold 

 spores as possible etiologic agents in asthma. It now seems well 

 established that asthma is due to an allergic state toward inhaled 

 substances which may be present in the air as dust. That mold 

 spores may be the exciting agents was suggested by van Leeuven.*^ 

 Cadham ^^ demonstrated that the spores of the wheat rust fungus, 

 Puccinia graminis, excited asthmatic attacks in certain cases he 

 studied. Hansen -^ observed a number of cases apparently due to 

 mold spores. These cases are first detected by cutaneous reactions, 

 but "Hansen applied rather strict criteria for establishing the di'ag- 

 nosis, involving demonstration of the mold in the habitual sur- 

 roundings of the patient, complete relief after removal from these 

 surroundings, an immediate relapse after experimental exposure to 

 the mold in question, and finally a positive Prausnitz-Kustner reac- 

 tion (passive transfer of the skin sensitivity to a normal person). 

 He found various species of Aspergillus most frequently gave reac- 

 tions. Hopkins, Benham, and Kesten "^' ^° reported a case due to a 

 species of Alternaria, and suggested that an eczema from which the 

 same patient suff'ered might be due to a similar cause. 



