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A model studied earlier in relation to aqueous 1–1 electrolytes has been applied to the interpretation of the excess free energies of aqueous solutions of the alkaline earth halides up to 1 M ionic strength. Several variations on the model could be fitted to the data. In the one which seems most consistent with the other observations, the cospheres (hydration layers) on the M++ ions were two water molecules thick rather than one as for the alkali metal, tetraalkylammonium, and halide ions. The overlap of cospheres of an M++, M++ pair was found to make a small attractive contribution to the interionic force, while the overlap of cospheres of an M++, X- pair makes a small positive contribution which is almost the same for X-=Cl-, Br-, or I-. Thus, ionic hydration shells which are not penetrated by other ions are not required to account for the observed excess free energies. The model is also fitted to NaCl-MgCl2 mixtures to see whether the new cosphereoverlap parameter which must be determined is consistent with the others. The calculation also shows how the thermodynamic behavior of the mixtures is consistent with the mixture limiting law for unsymmetrical mixtures. The singularities in the mixing coefficients g0 and w0 at infinite dilution dominate their concentration dependence only up to ionic strengths of about 0.01 M in models which fit the data.

NMR spectra reveal a ring current in substituted 4-pyrones which is not substantiated by magnetic susceptibility data. IR, polarographic, and hydrogen bonding data on 2,6-diaryl-4-pyrones are correlated with Hammett substituent constants.

A radiation‐induced transfer of hydrogen from exchangeable to carbon‐bound sites occurs in nucleic acids, proteins and their constituents. The G‐values for this process are similar within a factor of 2–3 to the G‐values for the initial production of stable radicals measured by ESR at room temperature. Unlike the production of radicals, hydrogen transfer in ribonuclease, DNA, and thymine is a linear function of dose in the 0–30 Megarad region. The tritium distributions obtained in proteins by hydrogen transfer are not a measure of the distribution of the “secondary” radicals. From the studies of the effect of temperature, of various scavengers (particularly nitric oxide) and of the dose dependence in the low dose region, it was inferred that for ribonuclease most of the hydrogen transfer takes place during the conversion of the radicals stable at 195°K to the radicals stable at room temperature. The same mechanism also appears to predominate in DNA.

All possible crosses among three species of sunfishes—the bluegill, Lepomis macrochirus Rafinesque; the redear, Lepomis microlophus (Günther); and the redbreast, Lepomis auritus (Linnaeus)—were successfully produced. One cross, female redbreast X male bluegill, was made by placing one adult of each species in a plastic pool and allowing them to spawn. The five remaining crosses were produced two to nine times each by stripping and artificial insemination. Progeny from five of the six possible crosses were stocked in plastic and/or concrete pools and allowed to grow for approximately 2 months. Samples from each cross were examined, and 10 meristic counts were recorded for each fish. Corresponding counts were made on samples from each parent species. The data provide characterizations of parent species and their hybrids as well as comparisons among them. The comparisons showed that hybrids were generally intermediate between their parent species in most taxonomic characters. A blending or multiple allelic inheritance rather than simple Mendelian inheritance was indicated in the determination of these characters. Other sunfish crosses were successfully made, but the progeny were not reared. The fertility of hybrid males from the F1cross of female bluegill X male redbreast was established in crosses with female green sunfish, Lepomis cyanellus Rafinesque, female bluegill, and female redear. Reciprocal crosses between the green sunfish and redear were made. Female green sunfish were also successfully crossed with a male redbreast and with a male bluegill.

THE freeze-drying technique permits the embedding of tissue containing water-soluble radioactively labelled compounds with minimal movement of the labelled material. However, the procedure for mounting the microtome sections later obtained from the tissue usually requires a mounting adhesive containing water or actually floating the ribbon of sections on water. During the latter procedure large amounts of radioactivity are lost from the sections—up to 100 per cent in some cases1. Using the ‘mounting adhesive technique’ the radioactivity may not be lost from the section; but, what is worse, it may move, giving a false impression of the previous localization in the tissue.