The degradation of glucose in acid solution was carried out at various temperatures. The first-order rate constants for the decomposition reaction, obtained from the initial rate of formation of 5-hydroxymethylfurfural (5HMF), were consistently higher than those calculated from glucose depletion measurements over long periods of time at temperatures above 100°. At 100° the rate of formation of 5-HMF increased with time for the early portion of the break-down. The rate constant did not coincide with the Arrhenius plot for higher temperatures. This indicates the possibility of a change of mechanism at lower temperatures. The rate data was fitted to kinetic expressions for first-order consecutive reactions. Agreement between calculated and experimental values indicates that the reaction proceeds by the step-wise mechanism. Data obtained from degradation in varying acid concentrations show that the rate constant does not vary linearly with normality. Decomposition in dioxane-water mixtures indicates that the logarithm of the rate constant varies linearly with the reciprocal of the dielectric constant.

Abstract Samples of synchronously growing cultures of Escherichia coli B/r removed at predetermined time intervals after synchronization were added to solutions containing bactericidal concentrations of tetra-cycline. Three active antibacterials, 7-nitro-6-demethyl-6-deoxytetracycline, 9-amino-6-demethyl-6-deoxytetracycline and 6-demethyl-6-deoxytetracycline, and one inactive compound, 7-chloroisotetra-cycline, were studied. Survival curves for the active agents, determined using samples of culture differing in age, were of constant slope for a given tetracycline. It is concluded that interruption of protein synthesis is the primary mode of action at bactericidal concentrations of tetracyclines, the same process as has been established for the action of the tetracyclines at the lower bacteriostatic concentrations.

Surface characteristics of particles and the intensity of particle interactions are presented as factors which may lead to caking of insoluble particles in aqueous dispersion. The degree of flocculation and the sediment volume were used as indexes of caking for sulfamerazine and bismuth subnitrate dispersions. Controlled particle flocculation by the addition of selected electrolytes produced a large volume of sedimented particles free from caking tendencies.

The plan of this investigation was to complex tetracaine HCl and some related local anesthetics with certain metal ions; and to determine the most acceptable complexing metal ions, the stability constants of the metal complexes under varying conditions, and the biological significance of such complexes.