MADUKA DISEASE 299 



therefore no doubt that the streptothrix madurae and the 

 actinomyces are distinct species. 



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 black 

 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 appear- 

 ance. 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. 



