782 Actinomycosis 



The characteristic rosettes so constantly found in the tissues are 

 never seen in artificial cultures. 



Agar-agar. — The best medium for cultivation seems to be agar- 

 agar containing i per cent, of dextrose or glucose. The trans- 

 plantations should be made deeply and the materia,l inoculated 

 distributed. The culture should be kept at incubation temperature. 

 Colonies appear scattered through the media in the course of a few 

 days, very few appearing close to the surface, and those a short 

 distance below being very small in size. The colonies wilt be found 

 most numerous in a zone about 5-10 mm. below the surface, where 

 they may meet with a gentle stimulation by small amounts of oxygen 

 absorbed from the air. Lower down, the colonies, though less num- 

 erous, grow much larger and form irregularly spherical or nodular 

 opaque areas, composed of branching filaments radiating from the 

 center. The filaments show true branching and tend after a time to 

 break up into segments and form a compact mass. 



When a puncture-culture is made in glucose agar, the organism 

 grows as an anaerobe in the line of inoculation, but never upon 

 or near the surface. 



Under anaerobic conditions the agar sfjread culture gave poor 

 success. 



Bouillon. — The growth takes place only at the bottom of the tube 

 in the form of solid whitish masses commonly of nodular irregular 

 character. The bouillon remains clear. 



Potato. — Potato cultures made under anaerobic conditions give 

 poor results. 



Peptone Solution. — Furnished poor cultures. 



Milk and Litmus Milk. — There are apparently poor media for 

 the cultivation of actinomyces. 



Eggs. — Wright tried ten strains of his organisms in eggs and egg 

 media but found very little growth. In one case there were long 

 filaments that appeared to be degenerated. 



Staining. — The organism stains easily and retains the stain in 

 Gram's method.. It is not acid-fast. j 



Metabolism. — Actinomyces grows only under anaerobic conditions. 



It does not ferment sugar, and does not evolve gas. 



Temperature. — The cultures grow only at 37°C. Wright found 

 the organism killed after fifteen minutes at 6o°C. 



Pathogenesis. — There is little evidence that the cultivated organ- 

 isms are pathogenic for laboratory animals. WolfE and Israel fre- 

 quently found nodular masses with communicating suppurating 

 sinuses containing the fungi, in the peritoneal cavities of inoculated 

 animals, but it is doubtful whether the organisms had multiplied 

 after inoculation or whether they would long have remained alive. 

 In the abdominal cavities of experimentally inoculated rabbits the 

 peritoneum, mesentery and omentum may show typical nodules 

 containing the actinomyces rays in cases of successful inoculation, 



