MADURA DISEASE. 



299 



described. Kanthack considered that the parasite was the same 

 in both, and occurred in the black variety in a degenerated form. 

 Boyce and Surveyor, on the other hand, pointed out differences, 

 and especially that in the black variety the parasite is more 

 highly organised and the branching filaments are thicker ; hence 

 they believed that it belonged to the hyphomycetes. The obser- 

 vations of J. H. Wright, who obtained pure cultures of a hypho- 

 mycete, are confirmatory of this view. The pigment may be 

 dissolved by soaking the granules for a few minutes in hypo- 

 chlorite of sodium solution, and the granule 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 hyphae, many of the seg- 

 ments of which are swollen ; at the periphery the hyphse form 

 .a zone with radiate arrangement. In many of the older gran- 

 ules the parasite is largely degenerated and presents an amor- 

 phous 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 trans- 

 verse 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. 



