412 



ACTINOMYCOSIS 



shows it to consist of a fine network of filaments radiating from a com- 

 mon centre. After several more days the colony assumes a yellowish 

 cloudy appearance. If one of these young first generation colonies is 

 taken up with a strong platinum loop and rubbed over the surface of a 

 glycerin agar slant and this is incubated, there appears, after twenty- 

 four hours, on the surface in patches a thin, gray, moist, gelatinous 

 film, which after another day becomes thicker and more cloudy. 

 After a further lapse of time whitish points project above the sur- 

 rounding surface and the growth, except at the very periphery, 

 becomes opaque. In older colonies the former projecting points have 

 become larger button-like masses which are elevated high over the 

 surface of the culture medium. These masses now become yellow or 

 yellowish red or even dark red (brick red), they are very firmly united 

 with the culture medium soil by filaments penetrating into its depth, 

 and it is difficult to remove them. They must be dislodged with a 

 strong platinum loop or spatula. The condensation water of the 

 culture tubes remains clear. In gelatin stick culture there is an 

 abundant growth on the surface, but little along the stick-canal. 

 The description here given refers particularly to actinomyces obtained 

 by Bostroem from persons and domestic animals. The fungi are 

 facultative aerobes; they grow much better in the presence of oxygen, 

 but can also grow in the absence of atmospheric air. Wolf and 

 Israel have, from two human cases, obtained actinomyces stems 

 which grow very poorly under aerobic but very well under anaerobic 

 conditions, particularly if inoculated into hen's or pigeon's eggs. 



FIG. 164 



Actinomycosis. Cover-glass preparation from pure culture showing true branching. X 1000. 



(Author's preparation.) 



Morphology of the Fungus in Pure Culture. If cover-glass prepar- 

 ations are made from pure cultures of actinomyces and stained with 

 Loeffler's methylene blue or by Gram's method, slender and more 

 coarse filaments which show true branching are seen. The filaments 



