Physiological Ontogeny . A. Chicken Embryos. X L I I . the Temperature Characteristic for the I~ate of the Whole Heart. Cosxracrio~i the Journal of General Physiology

Abstract

In a former paper in this series (1), Murray reported a study of the temperature characteristic of explants from auricles and ventricles of chicken embryos which was undertaken with a view to ascertaining whether a relation exists between the age of the embryo and this measurement. In the case of the explants he failed to find the relation. Fragments from hearts of embryos of the same age yielded different values and those of different ages, values which did not lend themselves to a characteristic arrangement. Murray suggested the possibility that if the observations were extended to a study of the whole embryo, in which the activities of all the structures were interrelated, greater uniformity of behavior might be detected. Crozier and Stier (2) have since reviewed Murray's conclusions. They doubt the probability of obtaining consistent values for the temperature characteristic ~ in preparations such as Murray used in which the absence of a controlling focus permits the independent and alternating activity of a number of non-related pace makers, that correspond neither in their rates nor in their internal metabolic activities. They think significant results are less likely to be encountered in studying organs of intact animals, but "suggest their probable occurrence in the heart rhythms of embryos." They suspect that this is the state of affairs because in developing Limulus there is "different chemical control of heart pulsation in embryo and in adult Limulus," and because of "the relative diversity of pace-making control in the developing embryos." 359

Cite this paper

@inproceedings{Cohn2003PhysiologicalO, title={Physiological Ontogeny . A. Chicken Embryos. X L I I . the Temperature Characteristic for the I~ate of the Whole Heart. Cosxracrio~i the Journal of General Physiology}, author={Eva Cohn}, year={2003} }