300 An Introduction to Medical Mycology 



coming directly off hyphae and sometimes in clusters (thyrsi and grappes). 

 Chlamydospores are common. Other forms are seldom observed. 



(f) Filtered ultraviolet rays.— Hairs infected with this fungus fluo- 

 resce, their appearance being not unlike that of hairs infected with T. vio- 

 laceum. The cultural growth is clear and bright. The color is dark olive 

 throughout. 



(g) Animal inoculation.— Guinea-pigs may be inoculated, but the le- 

 sions heal spontaneously. 



(h) Differential diagnosis.— An infected hair reveals an endothrix. The 

 cultural appearance of the endothrices is dissimilar. The culture mounts of 

 T. crateriforme and T. sulfureum show numerous microconidia and are 

 otherwise similar. ( See also the preceding section on T. violaceum. ) 



9. TRICHOPHYTON SULFUREUM 



This fungus is infrequently a cause of infections of the scalp or the 

 glabrous skin. 



(a) Clinical characteristics.— We have observed only two instances 

 of infection with this species. The scalp of a 4 year old girl showed scat- 

 tered, mildly crusted lesions on the occiput. The lesions were small. The 

 infected hairs were broken off above the surface of the scalp. In the other 

 case, a boy, 9, had a large circinate lesion of the glabrous skin with vesi- 

 copustules at the periphery and clearing in the center. An instance of 

 glabrous skin infection with secondary trichophytid was reported by 

 Slaughter and Cawley. 



(b) Immunologic reactions.— These are unknown. 



(c) Microscopic features.— Examination of the hair shows invasion of 

 the shaft, with large spores in linear arrangement. In the circinate lesion, 

 filaments were demonstrated, as in other forms of infection of the glabrous 

 skin. 



(d) Cultural characteristics.— Growth is moderately fast. The colony 

 is white and fluffy at first, later becoming yellowish gray and more com- 

 pact. Many radial grooves develop, and central convolutions and wrinkling 

 of the surface are early features. Subcultures may show a colony with less 

 folding, a more fluffy surface and a lighter color, which is almost buff. 



(e) Culture mount.— Some fuseaux are formed, and quantities of micro- 

 conidia ( thyrsi and grappes ) will be observed. Chlamydospores are also to 

 be seen. 



(I) Filtered ultraviolet rays.— Pale grayish fluorescence is present 

 when infected hairs arc examined. (Compare with Microspomm. ) 

 (g) Animal inoculation, and 



