RINGWORM 117 



which branch, and which appear to be composed of short rods. 

 There are often oval spores at the free ends of these branches, 

 and, according to Sabouraud, branching into three occurs 

 (trichotomous branching), and is very characteristic, though diffi- 

 cult to see. The radiation of several filaments from one point, 

 and the fact that these appear to be made up of short lengths, 

 gives rise to an appearance which has been compared to that of the 

 metatarsal bones, and the term " favic tarsus " has been applied. 



When favus affects the hair (Plate VI., Fig. 5), the cuticle 

 remains intact, and the inner portion of the hair is packed with 

 long waving filaments, whilst the outside (under the cuticle) is 

 covered with short " elements " — the exact nature of which is 

 doubtful — of every shape and size. 



The identification of the organism present (excluding the 

 distinction between the various species — e.g., of the epidermo- 

 phy^ons, which can only be accomplished by means of cultures) 

 is not usually difficult. The first point to be looked to is the 

 arrangement of the spores. If these form an irregular mosaic, 

 the microsporon is present ; if they form filaments somewhat re- 

 sembling those of a streptococcus, the organism is a trichophyton. 

 Then look to see whether the cuticle is intact, and whether the 

 fungus invades the interior of the hair. This can usually be 

 determined by focussing up and down until you see an " optical 

 section " of the hair in question. It is important not to be de- 

 luded by the fact that the fungus which lies on the outside of the 

 hair will appear to be inside it if a surface view only is taken. 



Ringworm of the Nails. 

 The nails may be affected by either of the trichophytons or by 

 favus. The diagnosis of the presence of ringworm may usually 

 be made by the examination of pieces of the nails after soaking in 

 liquor potassas, but a prolonged examination of many pieces must 

 be made before their absence is assumed. The diagnosis of the 

 variety present can only be made by cultures, and is not of clinical 

 importance (Plate VI., Fig 3). 



OTHER SKIN DISEASES 

 In scaling seborrhoeic affections the hottle bacillus of Unna is 

 constantly present, and as it does not occur at all frequently 

 in other diseases, if at all, it is a useful test between seborrhoeic 



