The protective effect of sodium chloride against thermal destruction of the phage-forming mechanism in staphylococci.

Staphylococci which have been allowed to grow rapidly in a favorable environment and subsequently have been maintained in a resting state characteristically produce a sharp rise in [phage] (activity) titre when added to phage. This capacity is quickly lost when the cells are suspended in distilled water and are exposed to 44 degrees C. for a period of 15 minutes; at the same time the viable count drops to approximately 1 to 3.5 per cent of the initial value. 1 M NaCl protects "activated" cells against thermal destruction and preserves the phage-augmenting property. "Non-activated" staphylococci in distilled water suspension do not show this thermolability.