Experimental researches, illustrative of the functional oneness, unity, and diffusion, of nervous action, of four sets of nerves, and a fourfold set of functions, and transmitted impressions : with a brief exposition of the philosophy of vivisection, and of sensation / by Bennet Dowler.

  • Dowler, Bennet, 1797-1879.
Date:
[1851]
Catalogue details

Licence: Public Domain Mark

Credit: Experimental researches, illustrative of the functional oneness, unity, and diffusion, of nervous action, of four sets of nerves, and a fourfold set of functions, and transmitted impressions : with a brief exposition of the philosophy of vivisection, and of sensation / by Bennet Dowler. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    repeated, does not diminish the muscular contraction, in degree, or in duration. The twitching of the muscle from compression of the nerve, is a curious, and an unexplained fact, which, however, does not disprove the doctrine that the muscles have a force inherent in themselves. That the nerves, in addition to their great sensational functions, may generate a force auxiliary to the muscular force, is not improbable :—the blood may contribute in like manner, since its own motions, particularly in the capillary system, seem to indicate an inherent force, which may be called vital, as it rises above any known mechanical force. The nerves are supposed to be the cause, and not simply the essen- tial condition of motion, because their division prevents it.* By parallel arguments the blood can be proved to be the cause, and not sinjply an essential condition of muscular motion, because its arrestation is followed by an instantaneous, general, and complete loss of motion and sensa- tion. Dr. Carpenter says : The contractility of the muscle is impaired or altogether extinguished, when the flow of the blood into it is arrested. * * * If the circulation through the brain be suspended but for an instant, insensibility and loss of voluntary power supervene, and con- tinue until it is restored. This was shown by the following experiment of Sir A. Cooper's. After having tied both carotid arteries in a dog, he compressed the vertebral trunks, and immediate insensibility came on, the animal at the same time falling powerless. As soon as the blood was re-admitted to the brain, the animal recovered its consciousness and voluntary power, and stood on its legs again. In syncope, the circula- tion through the spinal cord is weakened, a general cessation—not merely of muscular movement—but of all poweT of exciting it, is the immediate result. No sooner, however, is the circulation fully re- established, than the power of the nervous centres is restored. Dimin- *,low much vain theory has been suggested, from the simple experiment of loss of power in consequence of tying a nerve; and yet it was not the com- pression of the tubes of the nerve, but the obstruction of blood-vessels, which produced the effect. (Bell's Anat. and Phys. Edit. 1834. i. 54.) Such is Sir Charles Bell's latest opinion. When the very seat of perception is found not to be sensible, it leads us to consider on what the varieties of sensation depend. We see that sensibility, is not an accidental, nor a necessary consequence of the structure of a nerve, or the presence of the nervous matter, nor even the communication of that nerve with the brain. It is obvious, that the sensibility results from the particular part of the brain which is affected by the nerve. (Bell's Anat. and Fhys. Edit. 1834. i. 55.) Reader, read, and re-read this statement of Sir Charles Bell. Anatomy, the nervous matter—the functional intuitions of sense—all subjectivity or individual consciousness, and even all the brain, except the un- known particular part, are, like poor Cordelia's portion of King Lear's dominions, Nothing! Lear. Nothing can come of nothing; speak again.