ECTOTHRIX SPECIES OF TRICHOPHYTON 



171 



but it is not so marked as in the ectothrix species. Infections by 

 these transitional species are seen in subtropical America, Germany, 

 and Austria. 



There is one main species, Trichophyton epilans [T. cerebriforme, 

 T. plicatile): It produces ringworm of the scalp, the beard, and the 

 smooth skin, with varying degrees of inflammatory reaction. Plant 

 reports isolating it from cats. It may be inoculated on guinea pigs. 

 The colony resembles T. tonsurans but is yellower and the surface is 

 more wrinkled and folded. 



Ectothrix Species of Trichophyton. Ectothrix species of Tri- 

 chophyton are clinically sharply differentiated from the endothrix 



Fig. 84. A hair from ringworm of the scalp. This is a small-spored Ectothrix 

 Trichophyton. The spores are seen on the surface of the hair. 



types by the more pronounced inflammatory reaction which they 

 produce in the skin. This would seem to indicate a greater virulence. 

 These acute types of trichophytosis tend to heal more rapidly than 

 those with a less pronounced inflammation. Whereas with Micro- 

 sporum and Trichophyton infections the skin changes are usually 

 limited to congestion of the advancing border and scaling of the 

 epidermis, with infections from the ectothrix species there is also an 

 exudation of serum and leucocytes into the skin which leads to more 

 or less bogginess and infiltration of the deeper tissues. Not infre- 

 quently pus oozes in small droplets from the mouths of the hair ^ 

 follicles, or distinct pustules may appear. In more acute forms cer- 

 tain areas of skin may become elevated and feel quite boggy when 

 palpated, as though an abscess of some size were developing, and 

 pus oozes from the hair follicles when the skin is squeezed. Such a 

 lesion is called a kerion. Suppurative lesions of the beard are re- 

 ferred to as sycosis. 



The ectothrix species are divided into two groups, those with small 

 spores in the lesions (about 3 microns in diameter) and those with 



