918 



Favus. 



affected with favns; it was again described by Zander (1858). Further 

 reports and interesting exi)erinients have been pul)lislied bv Saint-Cyr 

 (1868), Siedanigrotzky (1872) and Cadiot (1889). 



As already related (see page 899) the Achorion Schonleinii was 

 first declared to be identical witli the Tricophyton tonsurans, but later 

 on it Avas recognized by Grawitz (1886) to be a different variety of 

 fungus, the multiplicity of which was defended in vain by several 

 authors (Quinke, Frank, Unna and others) against the objections raised 

 by Krai, Pick, Mibelli, Sabouraud, Tischutkin, and others. 



Occurrence. Faviis is frequent in man, mice and rats; a 

 rather rare disease in the cat, dog and rabbit, while in the cases 

 recorded in horses and cattle (Megnin, Gigard, Williams) it is 

 not certain that the}^ have not been herpes (Kitt, Neumann). 

 The disease appears as an enzootic, under certain conditions, 

 not only in mice but also in cats (Schindelka). 



Fig. 135. AcJiorion t^chUnlciuii from a luryv ciust of a inoiiso. a iMj'celium 

 threads and conidia ; b ejiiderinis cells. 



Etiology. The Achorion Schonleinii is found in the patho- 

 logical products in the form of glass-like homogenous or granu- 

 lar hypliM', 3 to 5 microns thick, ramifying, tapering at the end; 

 but in places, and especially at the ramifying places, knotty; 

 they appear gnarled and are matted together to form a d6nse 

 felted layer (m3^celium) in the meshes of which the spores, 

 wdiicli are usually few, 3 to 6 microns in size, ball, egg or biscuit- 

 shaped, or the conidia) of varying size, may be seen (Fig. 135). 



Culture. The cultural characteristics of the favus fungus have a 

 certain similarity to those of the Tricophyton tonsurans (see page 900), 

 yet in this respect there are differences which are not without im- 



