Behaviour and random mating

Résumé Des expériences portant sur le comportement sexuel chez plusieurs espèces, telles que la drosophile et la souris nous montrent que l'hypothèse qu'elles s'accouplent par hasard, hypothèse dont on fait état assez fréquemment dans la génétique des populations, n'est valable dans cadre des populations naturelles qu'avec de sérieuses restrictions.

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This work was supported by the Australian Research Grants Committee.     

Acetic acid vapour as a resource: Threshold differences among threeDrosophila species

Summary Acetic acid vapour is utilized as an energy source up to a threshold where it becomes a stress in 3Drosophila species. The threshold ranking isD. melanogaster» D. simulans>D. immigrans, which qualitatively parallels that for ethanol. The capacity to use nutritive vapours appears to be very important inDrosophila ecology.I thank Gary Spence for technical assistance, and the Australian Research Grants Committee for partial financial support.     

Transdermal uptake of a peptide hormone: Inhibition by calcitonin eardrops of induced osteolysis in guinea-pig ossicles

Summary In view of a recent proposal that calcitonin injections may arrest the bony pathology of otosclerosis, we have tested the possibility of obtaining locally effective concentrations by giving salmon calcitonin in eardrops. Osteolysis of guinea-pig ossicles induced by injecting parathyroid hormone shortly before explantation was markedly inhibited by 3 days prior instillation of the calcitonin in an aqueous vehicle or in dimethyl sulphoxide, but not by a solution in propylene carbonate.We thank Mr R. B. Christie, Armour Pharmaceutical Company Limited, Eastbourne for the supply of synthetic salmon calcitonin and Mr A.M. Oliver, for statistical examination of the data.     

Isolation of large sheets of frog skin epidermis

Zusammenfassung Nach Trypsinbehandlung abgetrennte Froschepidermis von bis zu 5 cm ø zeigt dieselbe Potenialdifferenz, Stromkurzschluss- und Sulfatpermeabilität wie die unveränderte Froschhaut. Die präparierte Epidermis besitzt fast keine Hautdrüsen, Jedoch fast völlig verschlossene Drüsenausführungsgänge.

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This work was supported by grants from the U.S. Public Health Service No. AM 05865 and No. GM 00899.