THE TRICHOPHYTON EAE 389 



Microsporwn audowni, Trichophyton crateri forme, T. acumina- 

 tum, T. sulfureum, and T. polygonum and that it is retained in the 

 hairs when treated with potassium hydroxide for indefinite 

 periods. In endothrix trichophyta and in favus, however, fluo- 

 rescence was attributed to keratin of the hairs. 



Davidson and Gregory (1932) noted that the ectothrix tricho- 

 phyta, Trichophyton gypseum and T. album, do not exhibit 

 greenish fluorescence, but with certain species with endothrix 

 hvphae, such as Achorion schoenleinii fluorescence resides in the 

 hair, as Kinnear (1931) maintained. They extended their obser- 

 vations by defatting, in warm water or in ether, hairs infected by 

 Microsporwn audpuini, M. felinum, or Achorion schoenleini and 

 then extracting with potash and secured a fluorescent extract. The 

 hairs so treated were no longer fluorescent. Normal hairs and 

 Trichophyton-infected hairs, moreover, did not yield a fluores- 

 cent substance by this same procedure. These results may be re- 

 garded as proof that the invading fungus produces some hydro- 

 lytic change in the hair substance and that this product has fluo- 

 rescent properties. The exact nature of the substance still remains 

 unknown. 



Physiologic activities. Both Tate (1929) and Dodge (1935) 

 have briefly reviewed the publications dealing with the physiology 

 of the Trichophytoneae that are peculiarly adapted to living on 

 keratinized tissues. Since the early studies- of Verujsky (1887) on 

 the activities of Trichophyton tonsurans and Achorion schoen- 

 leini many investigators have been concerned with the physiology 

 of this group of fungi. Verujsky found that both species grow 

 best in neutral or slightly acid media, with 3 3 ° C the optimum tem- 

 perature. Both produce proteolytic enzymes, as is evidenced by 

 the liquefaction of gelatin. Trichophyton tonsurans can utilize 

 glucose and maltose, but A. schoenleini does not possess the ability 

 to ferment these sugars. 



A considerable number of these fungi have been grown in pure 

 culture for periods varying from a few months to two years with- 

 out loss of virulence, such substrates as feathers, horn, leather, silk, 

 straw, and wood [Dodge (1935)] being employed. The organ- 

 isms tested include Trichophyton flavum, T. floccosum, T. granu- 

 losum, T. inter digit ale, T. mentagrophytes, Achorion gypseum, 

 and A. muris. 



