922 Favus. 



come as mncli as y^. em. thick and from their midst one or sev- 

 eral dusty Jooking hairs arise, which are rather loose and soon 

 fall out. The crusts are removed from the skin with difficulty, 

 and then leave behind a reddened, moist, hairless, trough-shaped 

 depression which, however, is soon covered with a thin layer 

 of epidermis and then has the appearance of a fine glistening 

 cicatrix, the skin appearing atrophic. By coalescence of neigh- 

 boring scutella, thick deposits of crusts may form which grad- 

 ually exfoliate in places. At the base of the claws, and still 

 more on the strongly haired parts of the body, crusts do not 

 show their characteristic shape but form only massive yellowish 

 brown or whitish yellow, cracked encrustations (Demons, Neu- 

 mann). The deposits may easily be crumbled up between the 

 fingers, whereupon a peculiar smell like mouse urine becomes 

 noticeable. The animals also give off a smell, reminding one 

 of cow cheese, if the disease is considerably^ extended. 



If the favus is localized in the neighborhood of the claws 

 these become thickened, loosened and brittle. The disease may 

 also be limited exclusively to the claws (Schindelka). 



The microscopic examination may be undertaken in the same manner as in 

 herpes (see page 915). Together with epidermis cells, fat droplets and granular 

 detritus, numerous filaments and spores of the favus fungus are formed in the 

 crusts (Fig. 135) and these are also to be seen in the hairs enclosed in them; yet 

 the hairs are not split and do not become white after treatment with chloroform 

 (compare page 915). In general the fungous hyphas predominate over the conidia3 in 

 the morbid products, but exceptions may be noticed in this respect. 



The alleged favus of the horse may occur on the head, chiefly at 

 the forelock and aroiiiid tlic eyes, where the crusts unite to form stripes 

 as broad as a finger (Schindelka). 



A contagious skin affection was observed ])y Wilbert in several military 

 horses, which was caused by the Oospora rubra, a fungus belonging to the Muearinese. 

 At first irregular, roundish, red patches appeared as large as a twenty-five to a 

 fifty-cent piece. The periphery was wavy and covered with a mealy deposit; in 

 places soft scales could be seen. Healing occurred in 3 to 4 weeks after washing 

 with soap and antiparasitic remedies, and after the internal administration of 

 arsenic. 



In sheep Kowalewsky claims to have o])served favus in enzootic 

 extension. In a flocli numbering 600 head, 300 animals became affected 

 with an exanthema characterized by dry, grayish white or grayish yellow 

 crusts, which developed on- the head, especially in the neigh])orhood of the 

 lips and nose, and on the inner surface of the external ear. The crusts had 

 a depressed surface and a corresponding ])ulging underneath and were 

 perforated each by 2 to 12 hairs. The parts of the skin covered by the 

 crusts were moist and reddened. On microscopic examination the pres- 

 ence of hypha? and spores was demonstrated. The general health of the 

 animals remained undisturlied and treatment with carbolic acid cured 

 them in a month. The affection, which, according to Neumann, very 

 much resembles sarcoptic scab, was not transmissible to dogs. 



In rabbits the disease has been observed repeatedly (Mourraud, 

 Reeordon, Megnin, Saint-Cyr). It chiefly affects the head and claws, 

 but any part of the body may be attacked. The process is similar, in 



