The hand : its mechanism and vital endowments, as evincing design, and illustrating the power, wisdom, and goodness of God / by Sir Charles Bell.

  • Bell, Charles, Sir, 1774-1842
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: The hand : its mechanism and vital endowments, as evincing design, and illustrating the power, wisdom, and goodness of God / by Sir Charles Bell. Source: Wellcome Collection.

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    The experiments performed by the author on the Portio- dura, which goes to the features, were in their results most decisive. To expose the nerve, he had to make only a small incision, scarcely larger than that for venesection; and when he cut it across, the effect was instantly visible. All the muscles corresponding to the distribution of the nerve were at once arrested in their motion—paralysed; but the sensi- bility of the skin was not in the smallest degree impaired. Among other animals on which he performed the experiment was the monkey; selected on account of the mobility and activity of his features. Before the operation, the creature was, of course, full of grinnings and grimaces at the liberties taken with him: the moment that the Portio-dura was severed, although his anger and jabberings did not cease, his face became passive and expressionless, like a mask. It was thus incon- testibly proved that the only function with which this nerve is endowed, is the power of giving motion to the muscles. The experiments which he next undertook were upon the Fifth. And he chose, first, those branches that emerge upon the face, at three distinct points, to supply the same parts to which the Portio-dura is sent. Although he doubtlessly perceived that, as motor power simply was conferred by that nerve, the remaining function, sensation, would, almost certainly, be be- stowed. by the only other distributed to the part, the Fifth, yet he subjected the branches to the necessary experiments. These branches have a particular interest attached to them, from the mode of their origin. Each comes off directly from the large, ganglionic root; and each pursues its course to its appropriate part of the face, without forming a connexion with any other nerve. The individual branches are, therefore, true representatives of the root from which they arise. Again] when they arrive at their destinations, they are situated quite superficially, being covered alone by skin; and they can be ex- posed for experiment with the utmost facility. Accordingly, experiments performed on these branches are essentially the same in value for determining the function of the ganglionic root, as if they had been made directly upon the root itself within the cranium. When these branches were cut across in a living animal, the result expected was obtained. It was shown that their property