Experimental researches, illustrative of the functional oneness, unity, and diffusion, of nervous action : in opposition to the anatomical assumption, 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, M.D., of New-Orleans (Corresponding Member of the Academy of Natural Sciences of Philadelphia).

  • Dowler, Bennet
Date:
1851
Catalogue details

Licence: Public Domain Mark

Credit: Experimental researches, illustrative of the functional oneness, unity, and diffusion, of nervous action : in opposition to the anatomical assumption, 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, M.D., of New-Orleans (Corresponding Member of the Academy of Natural Sciences of Philadelphia). Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    I had, as far as I can recollect, always applied the irritant to the limbs, or to the sides, but not exactly perpendicularly over the spine* The animals, as I now believe, had always perceived this, since they had always acted accordingly—as they had always curved their bodies lat- erally, sometimes they had rolled quite over, always from, never to- wards, the pain-producing agent. I found, on applying a lighted match perpendicularly over the spine, that the animal went straight for- ward. It would have crawled off the table had I not prevented it, by returning it to its original position. This experiment was several times repeated, and always with the same results ; which seem quite suffi- cient to establish the principle of possible forward vjoluntary motion after decapitation—^being so simple and satisfactory as not to aflow of mistake, while they show, at the same time, the accuracy with which the headless animal perceives and judges of the exact locality of an irritant. All of which may be inferred from the intelligent motions described. The next step of the vivisection, following decapitation, consisted in the division of the spine, including many muscles, at a point about one fourth of the distance from the hips to the shoulders. This diminished the activity of the trunk, but did not wholly prevent the mutual and simultaneous actions of the two divisions, in warding off injuries of either; thus, when a bit of burning paper was applied to the flanks, the fore legs were directed strongly to the seat of the pain, and in a straight line (that is, in the utmost degree of extension,) along the sides of the body, without any lateral flexure common to the trunk and tail, as seen before the second division, though the tail, hind legs, and body, as far as the division of the spine, continued to act in concert with the fore-legs. The division of the spine, together with the dorsal and cer- vical muscles, accounts for the absence of motion in the anterior half of the trunk. After decapitation, and even subsequent to the second division, the animal several times uttered a kind of guttural sounds, which were, at the time, attributed to the mere mechanical effects of the experiments, causing the expulsion of the air from the lungs, through the divided trachea. But it was soon ascertained, that several irregular respirations took place—irregular as to the times. Breathing, however, actually continued thirty minutes, by estimation. For about one hour, both divisions of the body gave proof of sensi- bility and voluntary motion ; that is to say, the fore-legs, the hind-legs, and the tail, were directed forwards, backwards, and upwards, and lat- erally, so as to avoid or remove (as it sometimes did,) an irritant. As the pain-giving agent was varied in its degree, and in place, so were 6