Bacterial death rate studies were carried out with several quaternary ammonium compounds. The survivor curves were found to be sigmoid. This shape was shown to be due to the difference in resistance to the QAC among the individual cells. An exponential rate was found when a more resistant strain was selected from the survivors of disinfection. Sporocidal action was not found. The reaction between substrate protein and the QAC removes the disinfectant from solution and occurs in the presence of a wide QAC–protein ratio, but the bactericidal action is dependent upon the concentration of the disinfectant. Serratia marcescens was adapted to grow in 200 times the originally lethal concentration of disinfectant, Escherichia coli in 43 times, but no increase in concentration was tolerated by Micrococcus pyogenes var. aureus.

The occurrence of acquired drug resistance in bacteria is now a familiar phenomenon and gives rise to serious problems in disinfection and in chemotherapy. It has been a matter of conjecture whether a strain giving rise to resistant progeny originally lacked homogeneity in respect of its drug susceptibility, or whether its enhanced resistance is a result of a direct chemical response of its biochemical processes. It has been shown recently (Chaplin, 1951) that certain bacterial species are capable of acquiring a great degree of resistance to the action of quatemary ammonium disinfectants, and at the same time it was shown that the strains used were definitely not homogeneous in susceptibility. It is a reasonable supposition, considering the supposed mode of action and the extreme surface activity of these compounds, that a profound change must be wrought in the cell surface during the acquisition of resistance. It is with the nature of this change

The influence of 3 spacings, 4 rootstocks, and 2 cultivars of apple (Malus domestica Borkh.) on yield, fruit and tree size and mineral composition of leaves during the 3rd through the 6th year of growth in the orchard were investigated. Scion cultivar had the greatest effect on mineral composition; all elements except manganese were significantly different in the 2 spur-type cultivars (‘Goldenspur’ and ‘Redspur’). Trees on Mailing Merton (MM) 106 rootstock produced larger yields than those on other rootstocks, and the foliage was usually among the highest in respect to each nutrient measured. Closely spaced trees had smaller fruit and the least amount of foliar P and K but Ca, Mg, and Mn were high in the same trees.

Leaves, shoots and flower buds of 3 peach cultivars differing in cold hardiness were compared biochemically throughout the year. The analyses included starch, reducing and total sugars, total protein, and total and individual amino acids, (a) Starch in leaves and shoots was low in early spring, but increased to peak concentrations in fall. Flower buds were devoid of starch, (b) Reducing and total sugars in leaves and shoots were high in early spring and decreased to a minimum in fall, but increased to a maximum in the shoots during winter. In flower buds reducing and total sugars were relatively high during winter and increased to peak concentrations in early spring, (c) Protein in leaves was high in spring but decreased to a minimum in summer, then steadily increased to a peak concentration in fall. A similar but less pronounced trend occurred in shoots. In flower buds a steady increase in protein occurred during dormancy and reached a maximum in early spring, (d) Total free amino acids in leaves was high in the spring, but decreased rapidly to a minimum in the fall. In shoots the level was relatively high in the spring, decreased in early summer, but increased to a maximum in late summer, then gradually leveled off during the fall and winter. In flower buds the level was relatively high in winter, but increased rapidly in early spring. Some correlation existed between the levels of the biochemical constituents and the degree of hardiness in the 3 peach cultivars.

Two soil organisins, ilrll~robacler pascelzs and Arllzrobecler lerregetzs, the first producing a growth-promoting substance, the "terregens factor", and thc second requiring it, pass through a complex morpl~ological life cycle. T I I~ kinds of aged cclls are found of which, on transfer to fresh medium, onc for~ns a cystite \vhich 'gcrminates' and looses free cells from a ruptured tube, the other follows thc ~~s u a l course of 'normal' cell cli~.ision. The similarity in for111 to that of the type species Artlrrobacter g1obifor1,ze is quite distinct.

Cold resistance of current season shoots of ‘Redhaven’ peach in the nursery as affected by 4 rootstocks was determined by electrical conductance. Significant conductance differences were noted on scion due to rootstock effects, and the most effective time for determining this difference appeared to be in early winter. There were significant differences due to late N applications. Late winter determinations showed that rootstock effects tend to diminish except at critical temperatures. There was variance in relative hardiness of stocks from 1 temperature to another or on different dates but, in general, ‘New’ and ‘Harrow Blood’ transmitted more hardiness to scions that did ‘Siberian C’ or ‘Rutgers Red Leaf’. ‘Siberian C’ was generally better than ‘Rutgers Red Leaf’.

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