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Updated: May 1, 2025
He had rightly pointed out that nerves were merely connections between the brain and spinal-cord and distant muscles and organs, and had recognized that there were two kinds of nerves, but his explanation of the action of these nerves was that "nervous spirits" were carried to the cavities of the brain by blood-vessels, and from there transmitted through the body along the nerve-trunks.
He has shown that in the larger nerve-trunks the nerve bundles for special groups of muscles are not, as was formerly supposed, arranged irregularly and fortuitously, but that on the contrary the nerve fibres to a particular group of muscles have a typical and practically constant position within the nerve.
While we had been supposing that the poison was carried, as almost every other known poison is, through the blood-vessels, or lymph-channels, to the heart and thence to the brain, he clearly proved that it ran up the central axis of the nerve-trunks, and consequently, when it had got once fairly started up this channel, was as safe from the attack of any antitoxin merely present in the general circulation and fluids of the body, as the copper of the Atlantic cable is from the eroding action of the sea-water.
So seriously was this believed, that, in amputations, the cut nerve-trunks were carefully sought out and tied, for fear the vital spirits would leak out and the patient thus literally bleed to death. One can imagine how this must have added to the comfort of the luckless patient.
The tendon cords, which are the ropes with which the muscles work the joint pulleys, were actually included under one head with the less numerous but almost equally large and tough cords of grayer color, flatter outline, and less glistening hue, which were afterwards found to be nerve-trunks.
In the hand, and more rarely in the foot, when one or other of the main nerve-trunks has been divided or compressed, the joints may become swollen and painful and afterwards become stiff and deformed. Bony ankylosis has been observed. In Affections of the Spinal Medulla.
Those affected become soft and flaccid, exhibit tremors on attempted movement, and their excitability to the faradic current is diminished. Neuropathic atrophy is associated with lesions of the nervous system. It is most pronounced in lesions of the motor nerve-trunks, probably because vaso-motor and trophic fibres are involved as well as those that are purely motor in function.
Now, when the part is cut off, the nerve-trunks which led to it and from it, remaining capable of being impressed by irritations, are made to convey to the brain from the stump impressions which are, as usual, referred by the brain to the lost parts to which these nerve-threads belonged. In other words, the nerve is like a bell-wire.
When this is difficult, a portion may be resected from each of the nerve-trunks at a higher level; and if this fails to give relief, a fresh amputation may be performed. When there is agonising pain dependent upon an ascending neuritis, it may be necessary to resect the corresponding posterior nerve roots within the vertebral canal.
In fact, from even the crudest and scantiest knowledge of the actual growth of our own bodies from the ovum to the adult, it will be difficult to conceive how this relation could be otherwise, The nerve-cells and their long processes, which form the nerve-trunks, are simply one of a score of different specialized cells which exist side by side in the body.
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