THE PATHOGENIC FUNGI 



1005 



their velvety white or faintly buff duvet and less active pigment production. 

 Microsporon Audouini produces only occasional and atypical fuseaux but 

 numerous chalmydospores which are frequently sub-terminal the hypha pro- 

 jecting beyond them like a spine. It also produces typical pectinate bodies. 

 Animal inoculation has been unsuccessful. Closely allied to this species are: 

 Microsporon umbonatum, M. tardum, and M. velveticum. 



Microsporon lanosum (M. Audouini, var. cams). This is the type species 

 of the microspora of animal origin. It produces ringworm in the dog. The 

 cultures grow very rapidly and on glucose are deeply pigmented. The duvet 

 is long, shaggy, and in older growths assumes a dark tan color. The upper 



FIG. 117. FUSEAUX OF MICROSPORON LANOSUM X200. 



surface is covered with a thick crop of typical lenticular fuseaux which alone 

 serve to identify cultures as belonging to this group. Experimental lesions 

 in the guinea-pig can be produced by the inoculation of cultures. Other 

 members of this group are: Microsporon felineum, M. equinum, M. fulvum, 

 M. villosum, M. pubescens, and M. tomentosum. 



TRICHOPHYTON 



The trichophyta, like the microspora, may produce ringworm of 

 the scalp but they also produce lesions on the glabrous skin and 

 nails. The genus is defined chiefly by the fact that its members 

 produce lesions without scutula and appear in infected hairs as 

 chains of spore-like elements. This alignment of the so-called spores 

 (which are in reality short mycclial elements) distinguishes them 

 from those of the preceding genus. In most trichophyta, too, the 

 spores are large but in a few they are of about the same size as 

 those of the microspora (3 microns). In culture most species produce 

 conidia attached to the hyphae by pointed tips and frequently 



