Il8 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



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. 



To search for it, take a scale or two from the affected region and 

 grind it in a drop of water between two slides until reduced to a 

 pulp. Allow some of this pulp to dry on one of the slides, fix, 

 stain by Gram's method, and do not counterstain. If the film is 

 very greasy, so that the stain does not wet it, warm the slide 

 gently and allow a few drops of ether to flow over the film, fix 

 again, and proceed as before. Examine the preparation under 

 a Jg-inch. The presence of the bottle bacillus is almost conclusive 

 evidence in favour of seborrhoea, as against psoriasis, syphilis, etc. 



The figure (Plate IV., Fig. 6) I owe to the kindness of 

 Dr. Whitfield. It is from an impure culture, the first ever 

 obtained. It has since been obtained in pure culture. 



Tinea Versicolor. — There is usually no difficulty in the diag- 

 nosis of this disease by ordinary clinical methods. Where there is 

 any doubt, one of the scales may be removed and examined in liquor 

 potassse, or by any of the methods described for ringworm. 

 The fungus — M. fuvfiw — is readily detected under a -^--inch. It 

 consists of rather wide mycelial threads, branching and inter- 

 lacing, with masses of refractile spores, looking like bunches of 

 grapes (Plate IV., Fig. 4). 



Erythrasma. — This is caused by the Micyosporon minutissimum. 

 The parasite affects usually the inguinal region, but is occasion- 

 ally found on the axillae and trunk. The fungus is very small 

 and can only be detected with certainty by staining the scales, 

 when it appears as long, very fine interlacing mycelium, termin- 

 ating in club-shaped spores. It is so much smaller than the 

 other moulds that a j-\ must be used to detect it. 



