52 



MICROHMS, FERMENTS, AND MOULDS. 



germinate wherever the conditions of heat and moisture 

 are favourable, even on a healthy skin, or where it is 

 only irritated by a simple scratch. 



Ringworm, Achorion Schosnlenii, the fungus 

 which produces this disease on the parts of the 

 skin covered by hair, belongs to the same family as 

 oi'dium. Its mycelium produces hyphse, bearing 

 chaplets of spores, as in the Mucorinese, but there is 

 no true sporangium. 



Fig. 24. Achonon Schcenlenii, fungus of ringworm ( x 400 diam ) : a, spores ; b, chains 

 of spores ; c, mycelium. 



They are found in abundance in spots of ringworm, 

 amidst the sulphur-coloured substance which carpets 

 them. If a morsel of this substance is dissolved in 

 ammonia, the fungus is detached, and may be observed 

 under the microscope, especially if care has been taken 

 to stain it brown by an aqueous solution of iodine 

 (Fig. 24). 



