CHAPTER XXXIV 



Fungi Probably Pathogenic 



THE list of fungi which are probably pathogenic is too long, and a dis- 

 cussion of all the fungi in it would become too involved for this 

 text. There is evidence that the fungi to be mentioned are capable of caus- 

 ing disease in human beings. 



1. ASPERGILLUS FUMIGATUS 



This mold has been isolated by many different observers from diseased 

 tissue (see the section on otomycosis, Chapter IX, pp. 168 f., and on asper- 

 gillosis, Chapter X, pp. 219 f. ). Its chief role is probably that of a secondary 

 invader; in that capacity it may be responsible for the continuance of an 

 infection originally caused by some other micro-organism. On dextrose 

 agar the growth is filamentous and greenish. The conidial head is green, the 

 stalks are smooth, and the vesicle is flask-shaped; the sterigmata occur in 

 one series and round conidia in narrow columns. 



2. PITYROSPORUM OVALE 



During recent years many studies have been made of the possible patho- 

 genic role of P. ovale, a fungus originally described by Malassez and also 

 known as the bottle bacillus of Unna. The investigation of its patho- 

 genicity has been hindered by the difficulty of obtaining a cultural growth. 

 Success in growing the organism was reported by MacLeod and Dowling 

 in 1928. Previously Unna, Engman, Castellani, Templeton, Acton and Panja, 

 and Ota and Huang reported occasional success in attempts to cultivate the 

 fungus. Templeton employed a preparation containing beer wort agar. 

 Moore used wort agar (Difco), a medium made especially for the cultiva- 

 tion of yeasts; subcultures were usually made after three or four days. 

 Moore reported success in culturing P. ovale in approximately 10 per cent of 



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