DEPILATING THRUSH. 



535 



{English, Canadian^ or American variola of the horse). The first 

 two are bj far the most important. A lengthy discussion has 

 occurred in order to find out if the fungi which determine these 

 belong to two species, or if they constitute but two varieties of the 

 same type. Microscopic examination does not reveal any well-de- 

 fined difference between the mycelium and the spores of these para- 

 sites, and till lately they have been confounded between themselves 

 and also with Oïdium albicans. But the recent researches of Grawitz ^ 

 have established that herpes and favus are produced by two distinct 

 parasitic species. If the spores of both fungi seem morphologi- 

 cally identical, they nevertheless offer remarkable differences in 

 their growth, also in their power to liquefy gelatin, and, again, in 

 the form of the cultures and conditions of reproduction ; concerning 

 Oïdium lactis, it has nothing in common with them. The non- 

 identity of these diseases is also indicated by their symptomatology, 

 and the absence of a transition form between the one and the other 

 would itself suffice to make us separate depilating herpes and favus. 



Besides these dermatomycoses, the bibliography of the subject 

 contains others in which the nature of the fungi could not be ex- 

 actly determined. Siedamgrotzky ^ has described a cutaneous affec- 

 tion which is altogether similar to circinated herpes, but in which 

 it has been impossible to establish the presence of the Trichophyton. 

 In a rooster, Leisering^ observed a localized eruption around the 

 cloaca, which was accompanied by falling out of the feathers ; it 

 was transmitted to the hens by copulation. By microscopic exami- 

 nation of matter which was obtained from diseased spots, greenish 

 conidia (spores) were found. Leisering* and EngeP have also 

 described a few vegeto-parasitic diseases of the mane and the base 

 of the horse's tail. 



DEPILATING THRUSH. 



Etiology. Depilating thrush has been designated by the ex- 

 pressions depilating dermatomycosis, decalvant thrush, tinea scutel- 

 lata, thrush of the calf's mouth, scurvy/ of the goat, lambs, etc. ; it has 



the chickens (Neumann). Eivolta and Silvestrini regard this disease as related to 

 psorospermosis. Cornil and Mégnin look upon it as a form of tuberculo-diphtheria. 



— N. D. T. 



1 Virchow's Archiv, Bd. ciii., 1886. 



2 Siedamgrotzky : Sachs. Jahresber., 1872. 



3 Leisering: Wochenschr., 1867. * Ibid., 1868. 

 à Engel: Ibid., 1881. 



