MICRO SPORUM 



991 



1. The downy type is found on the ordinary sugar media in 

 which there is an abundant development of white duvet. Micro- 

 scopically, fructifications of the type Acladium are seen, the spore- 

 bearing hyph« presenting numerous lateral sexile conidia. Sub- 

 cultures will always give rise to the same downy type. 



2. The glabrous type is observed on wort agar. The growth 

 has a smooth surface, without duvet. Microscopically, short 

 strings of hyaline, ovoid, or cylindrical conidia are seen inside the 

 terminal segments of the fertile hyphse. Lateral conidia are absent. 



Mode of Infection. — Infection takes place from man to man in 

 the case of microsporons of human origin; from the lower animals 

 to man in the case of microsporons of animal origin. The human 

 microsporons [M. audouini, M. velveticum, M. umhonatum, M. 

 tardum) do not seem to be inoculable into the lower animals. 



Table showing Species of Microsporum Parasitic on Man. 



Species. 



I'M. audouini Gruby, 1843. 

 J M. velveticum Sabouraud, 1907. 

 1 M. urabonatum Sabouraud, 1907. 

 ^M. tardum Sabouraud, 1909. 

 ''M. scorteum Priestley, 1914. 

 M. minimum Le Calve et Mai- 



herbe, 1898. 

 M. lanosum Sabouraud, 1907. 

 M. felineum C. Fox and BlaxalL 

 1896. 



< M. fulvum Uriburu, 1907. 

 M. pubescens Sabouraud, 1909. 

 M. villosum Minne, 1907. 

 M. tomentosum Pelagatti, 1909. 

 M. iris Pasini, 191 2. 

 M. fiavescens Horta, 191 2. 

 ^M, depauperatum Gueguen, 1912. 



Some species (M. audouini, M. velveticum, M. umhonatum, 

 M. tardum) seem to be parasitic on man only; others {M. lanosum, 

 M. felineum, M. minimum, etc.) are parasitic on the lower animals, 

 but occasionally infect man. 



Microsporum audouini Gruby, 1843. 



This parasite was described by Gruby in 1843, but his investi- 

 gation was forgotten, till Sabouraud, in his classical researches 

 on ringworm in 1892, demonstrated the plurality of species of 

 the fungi found in this affection, and showed that a form of tinea 

 capitis was due to the microsporon described by Gruby. 



Parasitic Life.— Around the affected hairs the fungus forms by 

 means of its mycelial spores a white opaque sheath, extending 2 

 or 3 millimetres above the opening of the hair follicle. The sheath 

 is composed of a mosaic of small, roundish, or polyhedral spores, 

 the diameter of which varies between 2 and 3 /bc. In the interior 

 of the hair a few mycelial filaments of the fungus may be observed. 

 The fungus very seldom attacks glabrous parts of the body. 



Genus. 



of human origin 



Microsporum Gruby, 

 1843 



of animal origin 



