TRICHOMYCOSIS AXILLARIS FLAVA 



2103 



Characters of the Coccus-like Organism found in the Black Variety [Micrococcus 

 or Nigvococcus nigrescens Castellani, 191 1). — It is a Gram-positive, rather large, 

 non-motile coccus, which in certain media may take the appearance of a 

 cocco-bacillus. Sugar media are more suitable for the growth of the organism 

 than the ordinary agar. 



Sahouraud Agar. — Colonies appear twenty-four to forty-eight hours after 

 inoculation. They are roundish, at first white, but after a couple of days 

 the centre of each colony turns black, and this pigmentation slowly spreads 

 excentrically. After a time the colonies coalesce into a jet-black mass. 



Glucose. — Growth similar to Sabouraud, but slightly less abundant. The 

 black pigmentation develops from the centre of the colonies and slowly 

 spreads towards the periphery. 



Ordinary Laboratory A gar .—-GTo^srth. much less abundant than on most 

 sugar agars, and black pigmentation less marked. 



Levulose Agar. — Identical to glucose. 



Saccharine Agar. — -The pigmentation is less pronounced, and does not 

 spread to the whole of the growth. 

 Raffinose Agar. — Same as saccharine. 

 Lactose Agar. — -Scanty pigmentation. 



Alkaline Maltose Agar. — Black pigmentation well marked, though in 

 many cases it does not extend to the whole of the growth. 



Acid Maltose Agar. — Growth less abundant than on acid maltose. Black 

 pigmentation well marked. 



Mannite Agar. — As alkaline maltose. 



Inulin Agar. — As alkaline maltose, but pigmentation less pronounced. 

 Saccharose. — As inulin. 



Glycerine Agar. — -Abundant growth, the whole of which after a time becomes 

 of jet-black colour. 

 Galactose. — As inalin. 

 Adonite. — Like acid maltose. 



Serum. — Growth fairly abundant, but there is only a trace of pigmentation. 

 The medium is not liquefied. 



Gelatine. — No liquefaction. The growth on the surface shows after a 

 time some dark pigmentation, but the colonies along the stab are white. 



Milk. — No change. 



Broth. — General turbidity. A thin pellicle is often present. The micro- 

 scopical examination shows cocci arranged in pairs or irregularly. They are 

 not capsulated. 



Peptone Water. — Some growth at the bottom, while the rest of the tube is 

 clear. 



Sugar Broths. — No formation of acid or gas. 

 Indol. — Most strains produce a trace of indol. 



Characters of the Coccus-like Organism found in the Red Variety of the 

 Affection. — The coccus found in the red variety is more difficult to isolate 

 and grow than the coccus observed in the black type of the affection. As 

 a rule it grows better and shows more pigment on ordinary agar than on 

 sugar media. It is non-motile and Gram-positive. 



Agar. — The growth is at first white, then a red or red-yellowish or yellow 

 spot appears in the centre. The pigmentation very slowly progresses towards 

 the periphery, but seldom, if ever, spreads to the whole of the growth. On 

 maltose and glucose agar the same pigmentation is present, but on most of the 

 other sugar media no pigment is produced. Gelatine and serum are not 

 liquefied. This coccus, as already stated, is Gram-positive and non-motile. 

 The coccus has been recently further investigated by Chalmers and O'Farrell, 

 who have observed that the best medium for showing the pigment is the potato. 

 They have called the coccus Rhodococcus castellanii. 



Symptomatology— The affected hairs of the axilla present 

 nodular formations, plainly visible to the naked eye, of rather soft 

 consistency. They are easily removed by scraping with a tri- 



