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MICRO-ORGANISMS AND DISEASE [chap. 



it occurs frequently in putrid organic matter ; in meat that 

 has been exposed to air and is undergoing putrefaction it is 

 often associated with proteus vulgaris. Its colonies in 

 nutrient gelatine are very characteristic (Fig. 58) : already 

 after twenty-four, better after forty-eight, hours' incubation, 

 whitish dots are seen which are made up of numerous 



Fig. 58. — Impression of a Colony in Gelatine Plate of Proteus Zenkeri. 

 Magnified with a glass. 



bundles of more or less beaded filaments radiating from a 

 shorter or longer line situated in the depth ; in addition to 

 this, irregular grey groups of plate-like masses seem to pass 

 out and to spread from the central mass on the surface. The 

 mass of threads resemble a mycelium of fungus ; the presence 

 of the grey plate-like masses makes it at once distinct. Under 



