. A Reference handbook of the medical sciences embracing the entire range of scientific and practical medicine and allied science . of the fifthnerve always diminishesthe frequency of the inhibition is there-fore of usual occurrence(lining the primaiy stage111 inhalation of chloroformnr ammonia. A condition of high in-tracardiac pressure has beenfound to reudor vagus in-hibition more difficult, andagain, beyond certain limitsthe arterial pressure cannot be greatly raised, so long asthe vagi are intact. There is apparently much to be saidin favor of the idea that the terminations
. A Reference handbook of the medical sciences embracing the entire range of scientific and practical medicine and allied science . of the fifthnerve always diminishesthe frequency of the inhibition is there-fore of usual occurrence(lining the primaiy stage111 inhalation of chloroformnr ammonia. A condition of high in-tracardiac pressure has beenfound to reudor vagus in-hibition more difficult, andagain, beyond certain limitsthe arterial pressure cannot be greatly raised, so long asthe vagi are intact. There is apparently much to be saidin favor of the idea that the terminations of the afferent 22 REFERENCE HANDBOOK OF THE MEDICAL SCIENCES. nerves on tlie inner wall of the hearl may be stimulatedby intracardiac pressure, and thus the controlling centresof the circulation as a whole—vagus, vaso-motor. andrespiratory—excited or depressed. If this be true, theheart possesses a mechanism for regulating , notonly its own rate, but the whole circulatory system. The cardio-inhibitory centre can be excited not only bythe character of the blood which comes into contact with. SSli.—Reflex InhiWtlon Produced by Inhalation of Ammonia. The upper line Is a tracingo£ arterial pressiue, the lower line that of the pulse. (Fran(,ois-Franck.; it, and by stimulation of afferent nerves (reflex), but alsoby cerebral stimuli. As is well known, the |uilse can bealtered by psychical and cniotioual conditions, and inh\pnotic subjects the pulse rate has been observed toundergo a marked change under the influence of sugges-tion. Search has been made on the surface of the cerebrumby cortical excitation, to discover if areas were presentwhich might influence the cardiac centre. If suitablestrengths of current were used to avoid the excitation ofepileptic flts, Fran^ois-Franck found that stimulation ofthe motor area with a weak current accelerated the lieart,while a strong current slo%ved the heart. The heart canalso be influenced from other pa
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