. A text-book of animal physiology [microform] : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. «<lili Ki'fTii her animals, the loft daring the a a meohanioi^ le heart reoom- yentrioles); hut animals. It it THB CIRCULATION OP THE BLOOD. 269 also a fact that in most of the cold-blooded animals the right vagus is moriB efficient than the left, owing, we think, not to the nerves th
. A text-book of animal physiology [microform] : with introductory chapters on general biology and a full treatment of reproduction, for students of human and comparative (veterinary) medicine and of general biology. Physiology, Comparative; Veterinary physiology; Physiologie comparée; Physiologie vétérinaire. «<lili Ki'fTii her animals, the loft daring the a a meohanioi^ le heart reoom- yentrioles); hut animals. It it THB CIRCULATION OP THE BLOOD. 269 also a fact that in most of the cold-blooded animals the right vagus is moriB efficient than the left, owing, we think, not to the nerves themselves so much as to their manner of distribution in the heart—^the greater jMrtion of the driving part of the organ, so to speak, being supplied by the right nerve; for, when even a small part of the heart is arrested, it may be overcome by the action of a larger portion of the same, or a more domi- nant region (the sinus mostly). OoMbuUnab—The inferences from the facts stated in the above paragraphs are these: 1. There is in the medulla a col- lection of cells (center) which can generate impulses that reach the heart by the vagi nerves and influence its muscular tissue, though whether directly or through the intermediation of nerve-cells in its substance is imcertain. It may possibly be in both ways. 2. This center (cardio-inhibitory) may be influ- enced reflexly by influences ascending by a variety of nerves from the periphery, including paths in the brain itself, as shown by the influence of emotions or the behavior of the heart. 3. The cardio-inhibitory center is the agent, in part, through which the rhythm of the heart is adapted to the niBeds of the body. 4. The arrest, on direct stimulation of the heart, is owing to the effect produced on the terminal fibers of the vagi, as shown by the dilation, etc, corresponding to what takes place when the trunk of the nerve or the center is stimu- lated. 5. The quickening of the heart, following section of the vagi, seems
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Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1880, bookyear1889
