YEASTS AND MOULDS 343 



It is composed of simple filaments interlaced. In the hair 

 bulbs, the filaments are inside the cuticle (endothrix) and- 

 running parallel to the long axis, and are formed of cells or 

 spores, almost square. These spores are 4 to 5 micra long, 

 and are regularly arranged in lines. It is readily grown 

 on Sabouraud's medium, showing in five to six days. It 

 liquefies gelatin. A variety is quite frequently met with 

 in the same places, T. Sabouraudi. It has a more fragile 

 mycelium, and shows round spores. 



Trichophyton mentagrophytes is a cause of sycosis 

 menti, a suppurative affection of the beard, and also of 

 ringworm of the body, and a suppurating ringworm of the 

 scalp in infants. The filaments are composed of strings 

 of round spores of varying diameters (2 to 10 micra). The 

 filamentary threads are mostly outside the hair cuticle ; 

 (endo- and ectothrix) ; a few are found inside but towards 

 the periphery. 



Microsporon or Microsporon Audouini is almost the 

 sole cause of ringworm of the scalp in Scotland, and of 

 96 per cent of the cases in London among British subjects. 

 It is called the small-spored fungus as compared with the 

 two given above, which are called " megalosporon," or 

 large-spored. The parasite encloses the diseased hair in a 

 whitish case formed of a mosaic of spores (ectothrix) . The 

 spores are 2 to 3 micra in diameter, and from pressure 

 against one another in the mosaic pattern, become poly- 

 hedral in shape. When stained with carbol-thionin, the 

 filaments are seen in the interior of the hair. 



Achorion Schoenleinii is the fungus which causes f avus, 

 or honeycomb ringworm, in which the characteristic 

 feature is the formation of cup-shaped crusts of a sulphur- 

 yellow colour. It most commonly attacks the scalp, but 

 also affects the skin of the body and the nails. When 

 attacking the nails, they become yellow and thickened. 

 Besides the characteristic form of attack, the fungus may 

 also produce a moist dermatitis resembling that due to 

 the other ringworm fungi. 



In the hair the parasite is seen as wavy lines of mycelia 

 composed of spores. The spores are irregular in size and 

 shape, but mostly polyhedral. Rarely, the mycelium is 

 septate and without spores. 



