Morphology 



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which four others have since been added, so that there are 

 now described, with or without justification, Trichophyton 

 crateriforme, T. acuminatum, T. violaceum, T. effractum, 

 T. fulmatum, T. umbilicatum, T. regulare, T. pilosum, T. 

 glabrum, T. sulphureum, T. polygonum, T. exsiccatum, T. 

 circonvulatuni, T. flavum, and T. plicatili. 



. In general it is customary to divide the organisms into two 

 groups, Trichophyton microsporon and T. megalosporon, 

 the former having large, the latter small, spores. 



Morphology. The trichophyton parasites form delicate 

 mycelia composed of somewhat slender septate hypha. 

 They can best be observed by ex- 

 tracting one of the hairs, including 

 its root, from the diseased area, 

 or if the affection be upon a hair- 

 less part of the body, by scraping 

 off some of the epiderm, and 

 mounting the material between a 

 slide and cover in a drop of caustic 

 potash solution (20 per cent.). 

 Under these circumstances the 

 spores are conspicuous and so 

 numerous as to give the impression 

 that they occur in rows in a kind 

 of structureless zooglea upon the 

 outside of the hair. In some cases, 

 however, especially in Trichophy- 

 ton megalosporon, the hypha may 

 be observed with the spores inside. 

 The hypha measure from 2 to 8 ^ 

 in diameter, are usually simple, 

 and rarely divide. The spores are 

 from 2 to 3 ^ in diameter in the 

 Trichophyton microsporon and 7 

 to 8 li in T. megalosporon. The former is the more com- 

 mon upon the hairless, the latter upon the hairy, portions of 

 the skin. 



Cultivation. The organisms may be secured in pure 

 culture without much difficulty, except for the annoying and 

 almost constant presence of the associated bacteria of the 

 skin. By crushing the hairs and scales in a mortar with some 

 dilute KOH solution, and then, after thoroughly distributing 

 the spores through the alkaline medium which dissolves many 





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! il 



Fig. 279. Invasion of a 

 human hair by trichophy- 

 ton : A, Points at which the 

 parasitic fungi coming from 

 the epidermis are elevating 

 the cuticle of the hair and 

 entering into its substance. 

 Magnified 200 diameters 

 (Sabouraud). 



