344 PUBLIC HEALTH BACTERIOLOGY 



Favus prevails also in mice and cats, and from the 

 latter animals many of the human cases arise. 



The Achorion Schoenleinii in culture grows best at 

 30 to 35 C, and scarcely grows at io to 15 C, unlike the 

 other ringworm fungi. It also liquefies gelatin more 

 quickly than they, namely, in three to four days. It 

 forms snowy-white circular or oval colonies, becoming 

 finely powdered over the surface, and wrinkled in old 

 culture. It grows best on beer-wort agar. To beer- wort 

 diluted to a specific gravity of 1100 add 1-5 per cent 

 of agar. Heat for two hours until dissolved. Filter, 

 tube, and sterilize. (Avoid overheating.) 



