. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. ijrgmographic carve it be said to be rtant law that >logical altera- Bration, which and expose it atly recurring ty be kept at a sriui of hours y to the heart, 1 of the vagus. ) undergoes a I or^an. This od oi not. THE CIRCULATION OF THE BLOOD. as5. 11. The heart may be arrested by direct stimulation, espe- cially of the sinus, and at the points at which the electrodes are app
. A text-book of comparative physiology [microform] : for students and practitioners of comparative (veterinary) medicine. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. ijrgmographic carve it be said to be rtant law that >logical altera- Bration, which and expose it atly recurring ty be kept at a sriui of hours y to the heart, 1 of the vagus. ) undergoes a I or^an. This od oi not. THE CIRCULATION OF THE BLOOD. as5. 11. The heart may be arrested by direct stimulation, espe- cially of the sinus, and at the points at which the electrodes are applied there is apparently a temporary paralysis. The same alteration in the beat may be noticed as when the main trunk of the vagus is stimulated. 12. The heart may be inhibited through stimulation of vari- ous parts of the body, both of the surface and internal organs (reflex inhibition). 18. One vagus being divided, stimulation of its upper end may cause arrest of the heart. 14. Stimulation of n small part of the medulla oblongata will produce the same result, provided one or both vagi be intaxst. 15. Section of both vagi in some animals (the dog notably) increases the rate of the cardiac beat. The result of section of one pneumogastric nerve is variable. The heart's rhythm is usually to some extent quickened. 16. During vagus inhibition from any cause in mammals and many other animals, the heart responds to a single stimu- lus, as the prick of a needle, by at least one beat. An observer studying for himself the behavior of the heart in several groups of animals with an open mind, for the purpose of observing all he can rather than proving or disproving some one point, be- comes strongly impressed with the variety in unity that runs through cardiac physiology, including the influence of nerve- cells (centers) through nerves ; for it will not be forgotten that normally nerves originate nothing, being conductors only, so that when the vagus is stimulated by us we are at the m
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