122 



STUDY AND IDENTIFICATION OF MOULDS 



Some give yellow cultures, others white and one derived from birds a rose- 

 colored culture. 



Microsporum audouini. This is the so-called small-spored ring- 

 worm and is a very common and highly contagious affection of the scalp 

 in children in England and France; less so in other countries. 



It is almost never seen in the tropics. It almost exclusively affects the hairy 

 scalp. The spores are 2 to 3^ in diameter. The broken stump of the hair is char- 

 acteristic. The fungus is packed as a mosaic of spores, forming a white sheath, 

 chiefly on the outside of the hairs. It gives a downy-white culture. 



9-08 . 



FIG. 42. Tropical fungi, i, concentric rings of Aspergillus concentricus; 

 2, sporangium of A. concentricus; 3, Aspergillus pictor; 4, Microsporoides minu- 

 tissimus; 5, Trichosporum giganteum; 6, black granules of Madurella mycetomi; 

 7, yellow grains of Discomyces madurae. 



Achorion schoenleini is the cause of favus. The cultures are rather 

 wrinkled. It is characterized by the scutulum or favus cup. This is a 

 sulphur-yellow pea-sized cup with a central lusterless hair. Affected 

 hairs may not show a cup. Favus is not so contagious as ringworm. 

 It chiefly affects the hairy scalp, but may also invade the nails and even 

 the body. 



Microscopical examination shows great irregularity of spores and mycelium, the 

 latter being irregularly disposed and of varying thickness and length and wavy 



