Etiology. 903 



Nevertheless, especially some French authors maintain the view 

 that the Tricophyton megalosporum or the Tr. microsporum, as also 

 the diseases caused by them (tricophytia or microsporosis) differ from 

 each other. But the researches of Krai and others are not in accord- 

 ance with this view, and besides the clinical differences given above are 

 not sufficiently marked to justify, at least for the present, the recog- 

 nition of two forms of the disease. 



Tenacity. Fungi that are preserved in the crusts resist desiccation for a long 

 time. Gerlach succeeded, for instance, in producing herpes tonsurans by rubbing 

 crusts into the scarified skin, which had been preserved in paper capsules at room 

 temperature for half a year. fSiedamgrotzky and Megnin could produce the disease 

 with herpes crusts that were 18 months old. Fungous material which was more 

 than two years old, however, remained non-effective (Siedamgrotzky, Duelaux), and 

 in cultures also the fungus had lost its power of germinating after 2 years (Thin). 

 In water the fungous spores can no longer germinate after 8 days, while in olive oil, 

 lard or vaseline they retain their vitality for only two days. They are killed 

 by a 1 per cent solution of acetic acid in an hour, but a one per cent of soda solu- 

 tion or sulphur ointment destroys them only after an exposure of several hours. 



Pathogenicity. Ground, up scabs or liairs containing tri- 

 cophyton fungi cause the disease after being simply rubbed into 

 the uninjured skin, but the fungi infect much more certainly 

 if the skin is moistened before the application and if the upper 

 layer of epidermis is scraped off or the skin gently scarified. 

 In young animals the first s;^inptoms appear in 8 to 14 days, 

 but if the skin had been moistened or scarified they appear 

 earlier, whereas older cattle are affected somewhat later and are 

 often not infected at all by simple rubbing in of the scab ma- 

 terial. If the fungus is placed lineally on the skin, one sees in 

 its wider spread the inclination to rounding off (Gerlach). 

 Artificial transmission is easiest from horses and cattle to cattle, 

 horses and dogs; it is most difficult from sheep and swine to 

 the other species of animals and even from sheep to sheep, and 

 swine to swine. Such transmissions can actually be made in 

 some cases from horse to sheep and swine (Siedamgrotzky, 

 Eailliet), from cattle to sheep (Eailliet, Schindelka), from goats 

 to cattle (Neumann), from cats to horses and cattle (Williams) ; 

 also from man to the cat (Fenger) and to other young animals 

 (Horand & Vincens), as also from animals to man (Gerlach, 

 Haubner, Bodin and others). Herpes may also be transmitted 

 from the domestic animals to guinea pigs and rabbits (Bodin, 

 Sabouraud, Friedberger & Frohner). The presence of pus cocci 

 in the skin checks the growth of the tricophyton fungus (Sabou- 

 raud, Marianelli). 



Natural infection results frequently by immediate con- 

 tagion, affected animals coming in contact with healthy ones in 

 the stable or still more in the stock yard or in the pasture. Suck- 

 lings are often infected while sucking affected mother animals. 

 The transmission may also occur in the covering act; in this 

 manner breeding animals may transmit herpes to entire herds 

 (Pusch). Finally animals may be infected by persons affected 

 with the disease. 



