RINGWORM 145 



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 epider- 

 mophytons, which can only be accomplished by means of cul- 

 tures) 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 resembling 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 ques- 

 tion. It is important not to be deluded 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 potassae, 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 seborrhceic affections the bottle 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 seborrhceic dermatitis and psoriasis, especially on 

 the scalp. It is a moderately large organism which consists 

 of an oval, spore-like body attached to a short neck or 

 handle. The former stains faintly, especially in the middle, 

 where it seems to have a clear vacuole, whilst the handle 

 stains deeply. It is very easily recognized after it has once 

 been seen; it is perhaps the only bacterium which can be 

 positively identified by microscopic means alone. It stains 

 by Gram. 



10 



