Abstract
LONDON. Royal Society, February 11.—Sir William Crookes, president, in the chair.—Dr. D. H. Scott: Lepidostrobus kentuckiensis, nomen nov., formerly Lepidostrobus Fischeri, Scott and Jeffrey.—A correction. The name Lepidostrobus Fischeri having been anticipated by Renault in 1890, it is necessary to give a new name to the Kentucky cone described by Scott and Jeffrey (Phil. Trans., Ser. B., vol. ccv., 1914, p. 354). The fossil is now named Lepidostrobus kentuckiensis.—T. Lewis and M. A. Rothschild: The excitatory process in the dog's heart. Part ii.—The ventricles. (i) The excitation wave appears at the pericardial surface of the dog's heart at times which show no great variation relative to each other; but the distribution of the time values over the surface with such variations as they show is very fairly constant from heart to heart. (2) The time at which the excitation wave appears at the surface is controlled by the length of the Purkinje tract to the endocardium beneath the region tested, and by the thickness of the ventricular muscle in the same region. (3) The excitation wave is not propagated by simple spread from base to apex or apex to base through bands of muscle fibres, as has commonly been held hitherto. (4) The capacity of striated cardiac tissue to conduct appears to be related to the size of the cells composing it and to its load of contained glycogen. (5) The auriculoventricular bundle and its branches constitute a system of fibres specially endowed in regard to their arrangement and physiological properties to give quick distribution of the excitation wave throughout all parts of the ventricle.—A. J. Walton: The variation in the growth of mammalian tissue in vitro according to the age of the animal. Previous work has shown that plasma of animals varies considerably in its value as a medium for the cultivation of tissue. The present experiments were caried out with a view of determining whether these differences were due to the age of the animal from which the plasma was obtained. The tissues and plasma of rabbits were alone used, and the majority of animals were of a known age. Tissues of young and old animals were used and were grown in pure plasma from the same animals. In all cases it was found that the young tissues grew better than the old, but the plasma of the young animal was not nearly so satisfactory a medium as that of the old animals. Hence the best results were obtained when young tissues were grown in the plasma of old animals and the worst results when old tissues were grown in young plasma.
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Societies and Academies . Nature 94, 690–691 (1915). https://doi.org/10.1038/094690a0
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DOI: https://doi.org/10.1038/094690a0