ACTINOMYCOSIS 101 



powdery deposit; and the culture assumes the 

 appearance, except as to colour, which is exhibited 

 by the various trichophytons. The culture material 

 generally darkens and becomes quite brown. Such 

 a culture on agar is shown (Fig. 104). 



In granules derived from bovine actinomycosis, 

 and in some cases of the human disease, the micro- 

 scopic appearance differs much from that described 

 above. The mycelial filaments are conspicuous by 

 their absence, or are so reduced in length and im- 

 portance as to be hardly noticed, and instead there 

 appears a rosette of Indian-club shaped rays, which 

 are strongly stained by Gram's method. 



Fig. 105, which is photographed from a section 

 of the tongue, shows this form of the organism. 

 These "clubs" are formed by a swelling — whether 

 degenerative or not is doubtful — of the sheaths 

 covering the swollen ends of the protoplasmic fila- 

 ments. The great varieties in appearance presented 

 by the organism in different cases is due to the pro- 

 portion which obtains between the ordinary myce- 

 lium and these modified club-shaped filaments, a 

 difference further accentuated by the fact that in 

 proportion as the mycelium increases, so does the 

 staining by Gram's method of such clubs as are 

 present diminish. There exists, therefore, at one end 



