Electro-physiology and electro-therapeutics : showing the best methods for the medical uses of electricity / By Alfred C. Garratt.
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to the trunks of nerves, or to those more circumscribed in desti- nation. Since the Pneumogastric nerve trunk is most superficial here, I will add that the functions of this important nerve are, accord- ing to M. Longet, as follows : — 1. From its orign above, as far as the superior jugular gan- glion, the pneumogastric is exclusively a nerve of sensation. 2. The stimulation of its proper fibres, as by the electricity, at their extremities, has especially the effect of inducing the reflex movements of deglutition, chymification, circulation, and respira- tion. At the same time it would be a serious error to suppose that, if the excitor influence of these fibres were cut off, the reflex motor actions would necessarily be abolished. 3. Beloiv the superior jugular ganglion the trunk of the pneumogastric represents a mixed nerve, exercising a motor influence, voluntary on some organs, involuntary on others. The voluntary power it owes to its direct motor fibres; the invol- untary, to the indirect before enumerated. 4. The sources of innervation required, to maintain the func- tion of an organ, are multiplied in proportion to its physiological importance. Thus the organic movements of the lungs, heart, and stomach are influenced by motor fibres coming from numer- ous points of the nervous system. It is the same witli the movements of deglutition, and with the respiratory dilatation of the glottis and uterus. 5. The anastomotic branch of the spinal accessory, which, to the exclusion of every other nerve, presides over the vocal move- ments of the larynx, only represents a partial motor root of the pneumogastric. 6. It is neither correct nor rational to conclude that, because, in the absence of this anastomotic branch, the phenomena of respiration, circulation, and digestion continue in animals, the pneumogastric nerve must be mixed at its origin. The internal branch of the spinal accessory is only one of the sources through which the trunk of the pneumogastric receives motor filaments from the cerebro-spinal centre. (See p. 47T, and Appendix.)