A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . igure repre-sents the inhibitory,augmentor fibers. the initial rate at which the heart is beating. the case of the inhibitory fibers, the effect is of adual nature, the increase in rate being generallyaccompanied by an increase in the size and forceof both auricular and ventricular effect may. moreover, apjjear alone, so thatthe name augmentor has come to be used sideby side with that of accelerator for these fact, the suggestion
A reference handbook of the medical sciences, embracing the entire range of scientific and practical medicine and allied science . igure repre-sents the inhibitory,augmentor fibers. the initial rate at which the heart is beating. the case of the inhibitory fibers, the effect is of adual nature, the increase in rate being generallyaccompanied by an increase in the size and forceof both auricular and ventricular effect may. moreover, apjjear alone, so thatthe name augmentor has come to be used sideby side with that of accelerator for these fact, the suggestion has been offered that theheart really receives four distinct varieties of nervefibers throtigh its extrinsic nerves instead of two,corresponding to the several results obtained byartificial stimulation, namely, accelerating, retarding,augmenting, and depressing fibers. It is interest-ing to note the effect of simultaneous stimulationof both inhibitory and accelerator nerves. It waslong believed that even feeble stimulation of thevagi was able to overcome comparatively strongstimulation of the accelerators, so that when both. Fig. —Blood-pressure Tracing (Rabbit). Vagus stimu-lated at /. Stimulus stronger in B than in .-1 (Hiirthles springmanometer). nerves were stimulated together the inhibitoryeffect predominated so long as the stimulus the cessation of the latter, however, the char-acteristic accelerator after-effect showed itself in asecondary ciuickening of the heart, indicating thatthe effect of the stimulus on the accelerator nerveswas only temporarily superseded. Later experimentshave shown that these two sets of nerves are trueantagonists, and that the effect of simultaneousstimulation is determined entirely by the relativestrength of the stimuli applied to them. Huntconcludes that in all cases the result is approximatelythe algebraic sum of the results of stimulating themseparately. The mechanism through which thesenerves produce their characteristi
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