332 ACTINOMYCOSIS AND ALLIED DISEASES 



granules, bearing a certain resemblance to the actinomyces, are 

 present. These may have a yellowish or pinkish colour, compared 

 from their appearance to fish roe, or they may be black like grains 

 of gunpowder, and may by their conglomeration form nodules 

 of considerable size. Hence a pale variety and a black variety 

 of the disease have been distinguished ; in both varieties the 

 granules mentioned reach a rather larger size than in " actino- 

 mycosis." These two varieties will be considered separately. 



Pale Variety. — When the roe-like granules are examined 

 microscopically they are found, like the actinomyces, to show 

 in their interior an abundant mass of branching filaments with 

 mycelial arrangement. There may also be present at the peri- 

 phery club-like structures, as in actinomyces ; sometimes they 

 are absent. These structures often have an elongated wedge- 

 shape, forming an outer zone to the colony, and in some cases 

 the filaments can be found to be connected with them. Yincent 

 obtained cultures of the parasite from a case in Algiers, and 

 found it to be a distinct species : it is now known as the 

 streptothrh- or discvmyces madurm. Morphologically it closely 

 resembles the actinomyces, but it presents certain differences in 

 cultural characters. In gelatin it forms raised colonies of a 

 yellowish colour, with umbilication of the centre, and there is 

 no liquefaction of the medium. On agar the growth assumes a 

 reddish colour; the organism also flourishes well in various 

 vegetable infusions. On all the media growth only takes place 

 in aerobic conditions. Experimental inoculation of various 

 animals has failed to reproduce the disease. 



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 hyphae, 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 grannies 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 



