296 An Introduction to Medical Mycology 



velvety surface with a pattern of irregular radial folds and elevations. 



(d) Culture mount.— Vegetative elements are simple, delicate and un- 

 differentiated. Chlamydospores are numerous. No free spores, fuseaux or 

 chandeliers are present. 



(e) Filtered ultraviolet rays.— A soft, pinkish-lilac color develops. 



(f) Animal inoculation.— Infection is difficult to reproduce in labora- 

 tory animals. 



(g) Differential diagnosis.— The colonies of this organism and of 

 Achorion schoenleini may be similar. The velvety surface and regular pat- 

 tern of grooves are usually distinct. The absence of chandeliers is suggestive. 



bibliography 



Fowle, L. P., and Georg, L. K. : Suppurative ringworm contracted from cattle, Arch. Dermat. 

 & Syph. 56:780, 1947. 



7. TRICHOPHYTON VIOLACEUM 



This organism is widely distributed throughout the world, being a com- 

 mon cause of infections of the scalp, beard and nails in Russia, Poland 

 and Italy as well as other European countries and states in the Near East. 

 It is not unknown in Australia. In the United States, the organism is 

 chiefly found in immigrants or their siblings, but sporadic cases have been 

 noted in native stock. 



(a) Clinical characteristics.— Infections caused by this fungus are 

 usually insidious in their development and exceedingly refractory to treat- 

 ment. On the scalp, the hairs are attacked and break off close to the skin. 

 Small pustules and follicular crusts usually form. Permanent scarring may 

 result. Similar mildly inflammatory lesions may appear on the bearded 

 region. When the infection spreads to the nails, rarely more than one or 

 two become affected. The nails are crumbly, yellowish and opaque. In 

 this location the fungus may be difficult to demonstrate. 



(b) Immunologic reactions.— Negative or very slight reactions are noted 

 after the intracutaneous trichophytin test. 



(c) Microscopic: features.— This organism is an endothrix Trichophyton, 

 invading the hair shaft. The spores are larger than those of the Microspore 

 and are arranged in rows or beads. No fungi are found on the surfaces of 

 the hairs. In scales or nail tissue, the organism is also observed in the form 

 of sporulated mycelium. 



(d) Cultural characteristics.— The rate of growth is slow; at prime the 

 colony is small and well defined. It is smooth, shiny, compact and almost 

 yeastlike, with a typical deep violet color. The surface shows convolutions, 



