Halobacterium cutirubrum, H. salinarium, and H. halobium required at least 10 p.p.m. ferrous ions for maximal growth in aerated cultures. The growth of H. cutirubrum was stimulated by 0.05 p.p.m. manganous ions but addition of divalent zinc or calcium had no effect on the growth of this organism.

Names are proposed for divisions, classes, and some orders of bacteria. The kingdom Procaryotae Murray 1968 is divided into three divisions: Gracilicutes divisio nov., Firmacutes divisio nov., and Mollicutes Edward and Freundt 1967, for organisms having, respectively, a gram-negative cell wall, a gram-positive cell wall, and no cell wall. Gracilicutes comprises the class Photobacteria classis nov. for organisms having a phototrophic metabolism and Scoto bacteria classis nov. for those having a nonphototrophic metabolism. Photobacteria is divided into two subclasses: Oxyphotobacteriae subclassis nov. for organisms that carry out an aerobic phototrophic metabolism, using water as an electron donor and producing oxygen, and Anoxyphotobacteriae subclassis nov. for those that have an anaerobic phototrophic metabolism. Oxyphotobacteriae comprises the orders Cyano bacteriales ordo nov. (formerly blue-green algae) and Prochlorales Lewin 1977. Anoxyphoto bacteriae contains the order Rhodospirillales Pfennig and Triiper 1971 and Chlorobiales ordo nov. The possible need of a fourth division to include organisms that have a rigid cell wall but do not contain peptidoglycan is noted. The name proposed for such a division is Mendocutes, that is, organisms having a cell wall with faults and blemishes.

The increase in volatile nitrogenous bases in codfish muscle between the pre-rigor period and the first appearance of odour is approximately 6 mg. per 100 grams of tissue, and is due almost entirely to the action of bacteria. It can be used to follow the course of spoilage only if the original value of the fish in question is known, as the range in variation of the original values is as great as the increase to the appearance of odour. A method for the rapid determination of "trimethylamine" in cod muscle has been devised. Its increase parallels the increase in bacterial population. Odours always appear at approximately the same level of "trimethylamine". The increase resulting from autolysis is negligible. The increase during the development of spoilage is fifteen to twenty times the original value. Spoilage can be followed in fish preserved with borates as well as in untreated fish.

A synthetic medium, made up of 15 amino acids, adenylic and uridylic acid, glycerol, asparagine or ammonium chloride, and various salts, has been developed for halophilic bacteria. Halobacterium cutirubrum and Sarcina litoralis grew as well in this medium as in a complex medium containing casein hydrolysate and yeast extract. Growth of Halobacterium halobium, Halobacterium salinarium, and Sarcina morrhuae was slower in the synthetic medium and the final cell densities were not as great as in the complex medium.

In the electron microscope, isolated cell envelopes of the extremely halophilic bacterium, Halobacteriunz cutirubrum, have the same hexagonal surface pattern and roughly the same shape as do intact cells. At different pH values and in different ionic environments the envelopes undergo changes in shape and surface structure similar to those of intact cells. These changes are probably not due to osmotic Dressure. In media of low ionic strennth envelooes disinte~rate. This disintegration appears to involve a t least tGo reaction's, both temperaturedependent.Chemical analyses show that envelopes consist mainly of lipoprotein. Both lipid and protein components are negatively charged a t neutral pH;and this may help t o explain the dependence on high cationic concentrations for envelope stabilitv. Most of the cell's ohos~hatides are oresent in the envelo~e. The main phosphbrus-containing compon&ts of cells 'are acid-soluble compounds and nucleic acids, whereas the main phosphorus-containing components of envelopes are phosphatides. Envelopes also contain small amounts of hexoses, hexosamine(s), and nucleic acids with a higher RNA/DNA ratio than found in intact cells, b u t neither muramic acid nor diaminopimelic acid was present. The lack of muramic acid in H. cutirubrum indicates that this halophile does not have a rigid mucopeptide wall of the type found in other bacteria. The lack of mucopeptide in envelopes is not due to autolytic digestion of mucopeptide during envelope isolation.