452 A MANUAL OF BACTERIOLOGY 



are found to contain round, ovoid, or reniform bodies 

 which have a rosette-like appearance, a more or less 

 structureless centre with club-shaped bodies radially 

 arranged around the periphery (Plate XIX. a). These 

 peculiar structures are the cause of the disease, and are 

 the form assumed in the animal body by an organism 

 belonging to the streptothrix group termed the Actino- 

 myces, or Streptothrix bovis (Nocardia bovis), or, from its 

 appearance, the ray fungus. 



Sections of the diseased tissues show the structure of 

 the organism still better. Gram's method usually gives 

 good results, and it will generally be found that the fol- 

 lowing appearances can be observed : Surrounded by the 

 round- cells are the reniform or ovoid bodies, situated at 

 the periphery of which are radially arranged, club-shaped 

 structures deeply stained with the gentian violet, while 

 the central portion is unstained and structureless, or 

 contains granular matter or calcareous particles. Various 

 appearances may be met with in different parts of the 

 section, according as the actinomycotic nodules are cut 

 through their centre or periphery ; when the latter is the 

 case, the clubs are shown in transverse section and appear 

 as closely packed, deeply stained dots. Sometimes, how- 

 ever, in addition to the clubs, the centre of the rosette is 

 occupied by numerous interlacing filaments, also stained 

 by the gentian violet. 



In man, actinomycosis is usually associated with sup- 

 puration. If a little of the pus be examined it will probably 

 contain tiny yellowish or sulphur- yellow granules, which, 

 microscopically, are found to consist of tufts of fine tangled 

 filaments, the ends of which may be continued into little 

 swellings or clubs. In teased-up specimens, or in sections 

 stained by Gram's method, an appearance is observed 

 very different from that of the bovine variety, viz. tufts of 

 interlacing filaments stained by the gentian violet, but a 



