Issued as Macdonald College Journal Series Number 520. 9 transformations of matter, would have very little point (76). Most of the experiments undertaken in attempting to settle the question have dealt with the temperature range and halophilic nature of bacteria from the sea. Marine bacteria were found to be generally more psychrophilic in character than terrestrial species and to prefer seawater or 3 7% NaCl to freshwater in the medium for growth. Evidence was presented, however, to indicate that these physiological properties were unstable. Baars (2), for instance, reported success in interconverting, by training procedures, three varieties of sulfate-reducing bacteria which, on the basis of temperature range, salt range, and habitat, had been regarded as separate species. ZoBell and Rittenberg (92) found that chitinoclastic bacteria from the sea, after prolonged laboratory cultivation or acclimatization procedures, developed the ability to grow in freshwater media. This change was accompanied by a widening of the temperature range for growth. Reports on the stability of the halophilic character of marine bacteria have been particularly