ACTINOMYCOSIS 453 



complete absence of purple clubs (Plate XX. a). Clubs, 

 however, are frequently present around the periphery of 

 the filamentous tufts in a stunted condition, although they 

 do not usually stain by Gram's method. These clubs are 

 often seen better in fresh specimens of the pus or in 

 unstained sections, or by staining with orange-rubin, or 

 the Ehrlich-Biondi reagent (Plate XX. 6). The con- 

 ditions in cattle and man, at first sight so very different , 

 are thus seen to be similar, a similarity which is further 

 established by the occasional occurrence in cattle of 

 filamentous tufts, staining by Gram's method, within the 

 rosettes, and by the clubs in man now and then taking 

 on the gentian- violet stain. 



Cultural characters. The cultivation of the Actino- 

 myces can be performed by collecting the pus from a case 

 of the disease in sterilised tubes, and subsequently turning 

 it out into a sterilised capsule and picking out the actino- 

 mycotic granules with sterilised needles, planting these 

 on the surface of glycerin agar, and incubating at 37 C. 

 A certain number of the tubes will probably be uncon- 

 taminated, but in others a growth of the Micrococcus 

 pyogenes var. aureus or other pyogenic organism, which is 

 not unfrequently associated with the Actinomyces, may 

 occur. In the uncontaminated tubes a growth begins to 

 appear in a few days in the form of little colonies of a tough 

 membranous consistence, somewhat wrinkled, greyish, and 

 shining, while the agar beneath them becomes stained 

 brownish. The growth increases and the colonies coalesce, 

 forming a brownish, wrinkled, membranous expansion, 

 sticking firmly to the agar^and difficult to remove or 

 break up, while the agar becomes stained brown through- 

 out ; later on the membranous growth may become 

 dappled with yellow as though powdered with flowers of 

 sulphur, but occasionally remains whitish. In gelatin 

 little spherical feathery tufts develop, and sink to the 



