342 CLINICAL BACTERIOLOGY. 



pure culture, and with this favus has been induced in animals 

 and in human beings. It may be mentioned that Quincke 

 succeeded in cultivating three distinct favus-fungi. More 

 recent investigations have, however, rendered it quite cer- 

 tain that in all varieties of favus but one fungus is found, 

 which, however, is not identical with the exciting agents of 

 the other parasitic skin-diseases. The favus-fungus grows 

 upon all nutrient media, both at the temperature of the body 

 and at room-temperature ; it grows best somewhat beneath 

 the surface, while only a small number of air-hyphae are 

 formed. The cultures are at first whitish, but later they be- 

 come yellow, and from the periphery radiating processes 



Fig- 75- Achorion Schonleinii : X 450 ; showing simple mycelium in various stages 

 of development, and free spores (after Duhring). 



extend into the depth of the nutrient medium. Microscop- 

 ically, a mycelium of branched hyphae is visible. Individual 

 hyphae swell at their free extremity into the form of a roll, 

 while others form lateral buds the so-called yellow bodies 

 of Krai which burst, so that their contents escape as a 

 free body. At these points the deep processes form. The 

 filaments themselves finally disintegrate into oval, cell- 

 shaped structures. 



Cultural Properties of the Achorion. On gelatin-plates 

 snow-white, star-shaped colonies, with an irregularly thick- 

 ened center, form. The culture-medium is quickly liquefied. 



In gelatin stab-cultures a thick, wavy, superficial deposit 

 appears, which is stained yellow beneath the surface. 



