CHAPTER XVI 

 TRICHOPHYTONEAE 



This group of Fungi Imperfecti appears to be parasitic almost exclusively 

 in the horny layer, or other keratinized structures (as hair and nails), of the 

 integument of mammals. The Trichophytoneae, or dermatophytes, are prob- 

 ably imperfect stages of Gymnoascaceae, although definite proof has been 

 found only in the case of Gymnoascus gypseus, and even here, others (Tate 

 1929) have not been able to confirm the results of Nannizzi (1926, 1927) and 

 Biltris (1929). Much data have been accumulated since the work of Matruchot 

 & Dassonville (1899, 1900, 1901) which points toward this conclusion, and it 

 is probable that work on suitable media and environmental conditions will 

 furnish the necessary proof. The figures of asci published by Wilenczyk 

 (1926, 1927, 1928) are unconvincing, and careful work by Bruhns (1930) and 

 others have wholly failed to confirm his statements. The work of Biltris 

 (1929) is vague and needs further confirmation, although it is suggestive. 

 The statement that the dermatophytes are related to the Ascocorticiaceae 

 seems altogether improbable. The only structure in common is the ascus, and 

 its mode of development is so different in the two groups that there seems 

 to be little probability of close relationship. 



Up to the present, attention has been centered primarily on the clinical, 

 pathologic and, to a lesser extent, morphologic aspects of the dermatophytes 

 with emphasis on the gross morphology of the giant colony and comparatively 

 little on the physiology. 



Most of the fundamental work on this group we owe to Sabouraud and 

 his students. Since his interest has been strongly clinical as well as mycologic, 

 he has evolved a classification based in part on the relation of host and 

 parasite. The older generation of mycologists considered this practice to be 

 of little value, although they were guilty of exactly the same practice in their 

 classifications of plant pathogens and saprophytes, and often carried their own 

 schemes to absurd lengths ; e.g., von Hoehnel and other workers in the Asco- 

 mycetes, who usually did not even take the trouble to cultivate their organisms 

 and practically never tried inoculations on various hosts. On the other hand, 

 Gueguen (1910) and, to a certain extent, Bruhns and Alexander (1928) would 

 base classification primarily on the lesions. 



Recently, we have had several attempts to introduce new classifications, 

 including the revision of Sabouraud by Castellani & Chalmers (1919) and by 

 Nannizzi (1926), a purely morphologic one by Vuillemin (1925)— both the latter 

 in violation of the fundamental principles of nomenclature — then an attempt 

 to apply the rules of nomenclature to Grigorakis' classification by Guiart & 

 Grigorakis (1927) a conflation of Ota & Langeron and Grigorakis by Ciferri 



433 



