370 



MICROBIOLOGY 



logically T. tonsurans consists of a mycelium about 4 /x thick 

 and spores (conidia), varying from 4 to 6 /x in diameter which 

 appear in short and longer chains. The mycelial filaments and 

 the spores occur in the crusts on the skin and in the diseased 

 hairs. The filaments branch at somewhat regular intervals. 

 The spores are seen as rows of highly refractive round bodies. 

 T. tonsurans is isolated with difficulty. It is cultivated ac- 

 cording to Sabouraud more readily on a Beerwort medium 

 composed of maltose 4 parts, peptone 2 parts, agar 1.5 parts 

 and distilled water 100 parts. On this medium a vigorous 

 growth appears. It liquefies gelatin forming a whitsh growth 

 on the surface which is hard to break but beneath it has a yel- 

 lowish color. On potato 

 a folded felty growth 

 appears. It is either 

 white, yellowish or red- 

 dish in color. 



This species first de- 

 scribed by Gruby * has 

 been more or less subdi- 

 vided. According to 

 some writers, true ring- 

 worm is caused by 

 moulds of two kinds, the 

 first being the Micro- 

 sporon Audouinif so 

 called by Gruby, the 

 other belonging to the 

 family of the T.richo- 

 phyt. The trichophy- 

 ton fungi are distin- 

 guished as T. endothrix 

 or T. ectothrix, according as they are seen microscopically to 

 occupy chiefly the interior or the exterior of the hair, respec- 

 tively. 



* Gruby described several varieties of fungi isolated from cases 

 of ringworm. Comptes rendu, Paris, between the years 1841 and 1844. 



b c c b 



Fig. 80. Trichophyton tonsurans 

 from a calf, a, hair; b, hair follicle; 

 c, fungus about the hair; d, threads of 

 fungus; e, epithelium. After Hutyra 

 and Marek. 



