330 ACTINOMYCOSIS AND ALLIED DISEASES 



Black Variety. The observations of J. H. Wright, who 

 obtained pure cultures of a hyphomycete, show that this variety 

 is a distinct affection from the pale variety. The pigment may 

 be dissolved by soaking the granules for a few minutes in 

 hypochlorite of sodium solution, and the granules may then be 

 crushed out beneath a cover-glass and examined microscopically. 

 The granules are composed of a somewhat homogeneous ground- 

 substance impregnated with pigment, and in this there is a 

 mycelium of thick filaments or hyphse, many of the segments 

 of which are swollen ; at the periphery the hyphae form a zone 

 with radiate arrangement. In many of the older granules the 

 parasite is largely degenerated and presents an amorphous 

 appearance. Wright planted over sixty of the black granules in 

 various culture media, and obtained cultures of a hyphomycete 

 from about a third of these. The organism grows well on agar, 

 bouillon, potato, etc. ; on agar it forms a felted mass of greyish 

 colour, and in old cultures black granules appear amongst the 

 mycelium. Microscopically the parasite appears as a mycelium 

 of thick branching filaments with delicate transverse septa ; in 

 the older threads the segments become swollen, so that strings of 

 oval-shaped bodies result. No signs of spore-formation were 

 noted. Inoculation of animals with cultures gave negative 

 results, as did also direct inoculation with the black granules 

 from the tissues. Brumpt, in a recent work, distinguishes 

 several varieties of parasite concerned in Madura disease, and 

 finds that a pale variety may be produced by a hyphomycete 

 as well as by Vincent's streptothrix ; in fact, with the exception 

 of Vincent's organism, all the parasites are considered by him to 

 be closely allied to aspergillus. 



