Category: S

Nutrient broth (commonly digest broth) plus 10 or 20 per cent sterile horse serum, for the cultivation of the more fastidious bacteria.  

Nutrient agar plus 10 per cent animal serum, for the cultivation of fastidious micro-organisms. Sterile hydrocele (or similar albuminous) fluid may serve in place of serum.  

Broths or peptone waters containing concentrations of agar less than that needed for a firm gel, but sufficient to indicate the presence of motile bacteria.  

Solid culture media designed to encourage the growth of specified bacteria and inhibit others which may be present in a mixed flora.  

Bacteriological filters composed of disposable asbestos discs clamped into a metal holder and funnel. The coarser discs (K or FCB) are for clarification; only the normal, ‘special EK’ or GS discs retain test bacteria.  

Bacterium the colonies of which acquire pigment while growing in the dark, an identifying feature of certain mycobacteria.  

Surface bacterial count performed by pressing a 2-inch length of tape on the surface under review, peeling off and presenting the adhesive side to an agar plate, then again peeling off. Colonies are counted on the incubated plate.  

Literally ‘fission fungi’—the Class of micro-organisms which includes the bacteria, but not the true fungi, rickettsia or viruses.  

Staining of bacterial spores with hot malachite green, the vegetative bacteria being then counterstained with weak safranine or basic fuchsin.  

The tendency of some bacterial species to colonize mainly (or to best advantage) around colonies of a second unrelated species, the latter providing some growth factor not present in the bulk of the medium.