DIAGNOSIS AND CULTIVATION OF FUNGI. IOf 



cause of Erythrasma or dhobies itch, a very common inter- 

 trigo of the tropics. It is characterized by its narrow 

 mycelium and small spores. Various fungi are found in this 

 affection. Castellani considers the cause of dhobies itch 

 to be a trichophyton. T. Cruris. 



Trichosporum giganteum. This is the cause of a disease of the hairs, 

 known in Columbia as "Piedra," so-called from the small 

 gritty- like masses along the length of the hair. These spores 

 are arranged like mosaics about the hair. 



DIAGNOSIS OF FUNGI. 



The most expeditious way to examine fungi is to treat the scales 

 or hairs with a 10% solution of caustic potash or soda. Then crush 

 between two slides; heat moderately over the flame and examine. 



Tribondeau's method is to treat the scales with ether, then with 

 alcohol and finally with water. Next put the sediment (it is convenient 

 to use a centrifuge) in a drop of caustic soda solution. Cover with a 

 cover-glass, and after the preparation has stood about an hour run 

 glycerin under the cover-glass. 



A very satisfactory method is to scrape the scales with a small 

 scalpel, and smear out the material so obtained in a loopful of white 

 of egg or blood-serum on a glass slide. By scraping vigorously the 

 serum may be obtained from the patient. After the smear has dried, 

 treat it with alcohol and ether to get rid of the fat. It may then be 

 stained with Wright's stain or by Gram's method. The ordinary 

 Gram method may be used or the decolorizing may be done with 

 aniline oil, observing the decolorization under the low power of the 

 microscope. 



Yeasts are best examined in hanging drop on the plain slide with 

 vaselin cell, as given under Blood. 



CULTIVATION OF FUNGI. 



Moulds grow well on media with an acid reaction, so that by 

 adjusting the reaction to + 2 percent or even higher, we permit of the 

 growth of the fungi, but inhibit bacterial development. 



