When compared at similar levels of water activity, glycerol was more inhibitory than sodium chloride to relatively salt-tolerant bacteria and less inhibitory than salt to salt-sensitive species.

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SUMMARYA new species of the genus Bacillus was isolated from Macquarie Island soil. The organism is psychrotrophic, producing spores at temperatures down to and including 0". The maximum temperature for growth is 25". Apart from its temperature relations, it most closely resembles B. pulvifaciens, but differs from that organism in its ability to produce acid from carbohydrates with ammonium salts as sole nitrogen source and in its inability to hydrolyse casein or gelatin, to grow on soybean agar or to grow in 5 yo NaC1. The name Bacillus macquariensis is proposed.Vegetative organisms stained Gram-negative a t all stages of growth. Electron micrographs revealed cell-wall structures typical of Grampositive bacteria; on the other hand, chemical analyses demonstrated in cell-wall preparations a wide range of amino acids and relatively low amounts of amino sugars, as commonly found in Gram-negative species.

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SUMMARYFreeze-dried spores of Bacillus megaterium, B. stearotkmphilus, Clostridium bifermentaw and C . botulinum type E suffered little or no loss in viability after storage a t 25" at water activity (a,) values between 0-2 and 0.8. When stored over P,O, (0.00 a,) the spores of all four species showed a marked loss in viability. The above results were similar for spores whether stored in air or in vacuum. With spores stored over distilled water (1.00 a,) the Bacillus spores underwent a large loss of viability in vacuum, but not in air; for spores of the clostridia the reverse was true. The addition of DL-glyceraldehyde, diacetyl or ribose (0.05 M) to the spore suspensions before drying caused increased death during storage at 0.50 aw and to a lesser extent a t 0.20 a,. Death was greater at 30' than at 10". The addition of sucrose, glutamate or semi-carbazide did not decrease the viability. When the dried spores were resuspended in dilute phosphate buffer after storage for 2-6 years their resistance to heating was greatest after storage at a, values of 04, 0.6 and 0.8.