THE PATHOGENIC FUNGI 1007 



The Gypseuni Group (Tr. asteroides, radiolatum, etc.) grow more vigor- 

 ously forming large colonies up to 10 cm. in diameter. The surface is 

 powdery or plaster-like, but the parasites soon become pleomorphic and 

 produce a long velvety duvet. They produce conidia in large clusters, rudi- 

 mentary fuseaux, and numerous spirals. The lesions are inflammatory, with 

 folliculitis and kerion formation. They cause ring-worm in horses. 



The Niveurn Group resemble the pleomorphic forms of the gypseurn 

 group. They form conidia only. 



Trichophyton rosaceum (the type of the Downy Megalospora) forms a 

 colony of medium size resembling a folded disc of white velvet. The deep 

 portion develops a crimson or violet pigment which gives a rose tint as 

 seen through the white duvet. It forms long thyrses and rudimentary fuseaux. 



The Faviform Strains (Tr. ochraceum, Tr. album, etc.) resemble culturally 

 the Achorion Schoenleini. They are grouped with the trichophyta chiefly 

 because they form no scutula in lesions. 



A description of all the individual species would exceed the scope 

 of this chapter. 



ECZEMA MARGINATUM AND POMPHOLYX 



Eczema marginatum or ringworm of the groin is a common derma- 

 tosis. In the lesions Castellan! and Sabouraud found a fungus to 

 which the latter gave the name Epidermophyton inguinale. More 

 recently Ormsby and Mitchell 43 and others in this country have 

 found the same fungus in eczematous lesions of the hands and feet 

 and also in the vesicular eruptions in these regions formerly called 

 pompholyx. Sabouraud has also found various species of trichophyta 

 in palmar eczemas. 



EPIDERMOPHYTON INGUINALE 



(Trichophyton cruris) 



In the epidermis the parasite is seen as long interlacing filaments 

 made up of oblong or oval cells with double contours. It develops 

 slowly in culture as a greenish buff colony with folds radiating from 

 a central or slightly eccentric peak, attaining a diameter of perhaps 

 two centimeters in a month. The surface at first is dry and powdery 

 but on sugar media it quickly becomes pleomorphic, developing a 



43 Ormsby, 0. 8., and Mitchell, J. H., Jour. Am. Med. Assn., 1916, LXVII, 711. 



