ACHORION SCHG@:NLEINII, 623 
bits, fowls; and dogs are also subject to it. It grows 
much more slowly than the ringworm fungus, and is, 
therefore, not so easily transmitted. Want of cleanli- 
ness is a predisposing factor. The fungus seems to 
find a more favorable soil for its development on the 
skin of persons in weak health, especially from phthisis, 
than in others. 
Pathologically, the disease represents the reaction of 
the tissues to the irritation caused by the growth of the 
fungus. The spores generally find their way into the 
Fie. 85. 
A portion ot a favus infected hair. Magnified. 
hair-follicles, where they grow round the hair-seat 
(Fig. 85). The favus fungus grows in the epidermis, 
_the density of the growth causing pressure on the parts 
below, thus crushing out the vitality of the hair and 
giving rise to atrophic scarring. The disease shows a 
marked preference for the scalp, but no part of the 
skin is exempt, and even the mucous membranes are 
liable to be attacked. Kaposi has reported a case in 
which a patient suffering from universal favus died, 
with symptoms of severe gastro intestinal irritation, 
which was found after death to be due to the presence 
