MICBOSPOKON AUDOUINL 153 



IV. Microsporon Audouini. 



Species Audouini (Gruby) = Champignon de la Teigne achro- 

 mateuse, decalvante, du Porrigo decalvans; Trichophyton aut 

 Trichomyces decalvans. 



Signa generis. Spori rotundi 0*001-5 mm.; ovales 0*002-8 mm., 

 aqua intumescentes, filamenta et rami breves. 



The distinctive character of Trichophyton tonsurans consists in 

 its numerous curved undulated branches, having generally smaller 

 spores, in the constant absence of granules in the interior, in the 

 spores adhering to the filaments and branches, and in its seat; 

 for whilst Trichophyton tonsurans is developed in the root of the 

 hair, Microsporon Audouini forms a tube around each hair, of the 

 thickness of 0*015 mm., and surrounds the hair outside of the 

 follicle. 



Habitat. In superficie capillorum hominis, qui folliculum rcli- 

 querunt, et usque ad altitudinem trium Millimetrorum supra cutis 

 superficiem ascendit. 



The filaments run parallel with the stripes on the hair; the 

 branches have the same diameter as the filaments ; the former 

 bear the spores. It is not yet known whether the germation of 

 the Microsporon requires at first a sort of exudation, or whether 

 the spores are able to develop themselves everywhere merely 

 under the influence of the epithelia and scales, and at the common 

 temperature of the human body. Its reproduction is owing to a 

 segmentation of the points of the filaments ; its growth is extra- 

 ordinarily rapid, for, in a few days, the parasites are found to 

 cover a space of 3 4 centimetres. Its development begins at 

 the outside of the hair, 1 2 mm. distant from the epidermis. 

 The hair becomes less transparent, is 0*030-40 mm. thick, and 

 very finely granulated, till it breaks at last. If the hair has 

 become gray from its root, it breaks off about a week after at 

 the spot where the sheath of the plant begins, and is 

 followed by baldness. The hair-epithelium likewise falls off. The 

 thickest hair resists longest. Around the follicles masses of the 

 fungus heap up, from J \ mm. in diameter, which have falsely 

 been taken for pustules, or secretion of the " Glandulse seba- 

 cea3." They are, however, una companied by inflammation, 

 hypertrophy cf the skin, pimples, or pustules. This fungus is 



