756 



Favus 



The organism can be studied by extracting a hair and examining 

 it in KOH or NaOH solution (20 per cent.), or by teasing a scutulum 

 in the same medium and examining with a low power. Sections of 

 the skin may also be made when possible. 



The fungus resolves itself into mycelial threads, and spores. The 







Fig. 317. Favus. Hairs of a child infected with Achorion schonleinii. A, 

 Magnified 260 diameters; B, 75 diameters. The large rounded bodies are drop- 

 lets of air which always appear after treatment with 40 per cent, potash solution. 

 The linear threads are the fungi. Some are without spores, others contain rows 

 of spores (Sabouraud). 



scutulum consists of masses of spores at the center and about the hair, 

 with mycelia containing spores at the edges. From the mycelium 

 hypha are given off, the ends being knobbed or clavate. 



The mycelial threads are highly refractile, contain granular proto- 

 plasm, and are of varying thickness. Sometimes the terminal 



