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the nervous power, it may be allowed to throw out as a hint for future consideration, that the cell nuclei so largely interspersed among the gray gelatinous fibres of the sympathetic ganglia and nerves, have no small analogy with the primitive forms of the vegetable world. In both kinds of organic life, the cell seems to be the first and simplest form assumed by incipient organization;* in both the granules contained within the cells have been seen in motion,t although no shock has been communicated to them externally. Whence this motion arises is not easy to decide, but movement being produced, the first condition of assimilation, and consequently of the maintenance of life, is there. And here a wide field opens itself:-electricity has been considered, nay, may we not say, proved, by Prof. Faraday to be merely a phenomenon of matter, the consequence of molecular movement communicated by chemical change; and Prof. Matteucci of Pisa has proved by a series of experiments that animal muscle is capable of taking the place of metals in forming a galvanic current:* and heat is generated where electrical action is excited. No series of experiments has yet proved that these isolated facts of science have any intimate relation to each other, but an inquiring mind cannot avoid asking the question, have they not?Is not the movement which is excited within the primitive cell, though perhaps merely the result of endosmose, the first step in a series of phenomena, each resulting from the other till the most complex machinery of organic life is developed and kept in action.t Whether the nucleated cells found so plenti• fully scattered among the gray fibres of the sympathetic system may generate and propagate such movement, of course is not, perhaps never may be, ascertained; but if it were so, it would be one more instance to add to the many that modern science has discovered, of the beautiful simplicity of means by which the mightiest effects are produced, where PERFECT KNOWLEDGE and PERFECT POWER have been employed in conjunction.

* See Carpenter's Physiology, p. 15.

† "Such motions are either of a uniform and rhythmical kind, or they are apparently irregular and oscillating. Those of the former kind are familiarly known in the vegetable kingdom by the Cyclosis which takes place in the oblong cells of Chara. The granules which may be seen in motion are quite passive, and are carried along by currents within the cell. Motions of the latter kind have been seen by Schwann among the granules contained in the cells of the germinal membrane of the hen's egg, as if occasioned by an endosmotic current through the wall of the cell. This membrane is the seat of active change, the development and growth of new cells destined for the evolution of the textures of the embryo. A molecular motion of the same kind may be seen in the very minute granules which occupy the cells of the membrane of black pigment on the choroid coat of the eye. Whether this goes on during life is of course impossible to say, but the conditions for its production are undoubtedly present." Todd and Bowman's Phys., vol. i. p. 59.

* "The organic actions of muscle by which the electrical current is developed may be compared to the inorganic phenomena attending its production from the decomposition of metals. When a plate of metal, immersed in an acidulated fluid, is oxidized by the oxygen of the water, and then dissolved in the acid, we admit that an enormous quantity of electricity is developed during this action. The metal acted upon in the artificial arrangement is represented, in the phenomenon of the muscular current, by the muscular fibre; the acidulated fluid is the arterial blood. The surface of the muscle, or any other conducting body, not muscular fibre, but which is in contact with the muscle, represents the second plate of metal, which does not suffer chemical action, and which serves only to form the circuit. The direction of the muscular current is precisely such as it should be supposing the current to be as we have represented it, due to chemical action taking place in the interior of the muscle." (The direction of the current is from the interior to the exterior.) The above is quoted from Matteucci's communication to the writers of the work on Physiology already quoted, vol. i. p. 383, and there the experiments are detailed by which Prof. Matteucci proved the facts above stated.

† Both electricity and heat are present in the germination of seeds; are not both, possibly, modifications of molecular move

ment?

13. We have now to consider another system of nerves differing both in function and appearance from the foregoing: i. e., the spinal. These issue from each side of the spinal cord, to the number of thirty-one pairs, but each individual nerve is attached to the cord by two sets of filaments (15) which from their respective situations are termed the anterior and posterior roots of the spinal nerves.* The posterior root is distinguished by a ganglion found on it near its point of junction with the cord; the anterior passes over this ganglion, but sends no fibres into it, although both at their exit from the vertebral column are wrapped in the same common covering: but presently after, the fibres of each root cross over each other, and the two great branches into which this compound nerve soon divides, contain bundles of fibres connected with both roots. It had long been observed that, in cases of palsy, sometimes the power of voluntary movement, sometimes the sense of touch was destroyed, and this, upon examination after death, was found to have been caused by a lesion of some part of the brain; at other times the same effect was produced by injury or disease of different parts of the spinal cord. About the beginning of this century this circumstance began to give rise to speculations on the possibility that the separate roots of the nerves might have separate functions, and that the fibres of each root which, though crossing and intermingling in their common sheath, are yet kept perfectly separate by the fine membrane or nerve lemma that invests them, might be the means of carrying to the brain the sensations received at the extremities, on the one hand, and conveying back its mandates on the other:-in short, that these roots were respectively sensitive and motor, consisting of fibres communicating with certain tracts of the spinal cord, which in their turn communicated with the brain, and thus that injury of any part of the sensitive tract would destroy sensation;-or in like manner impede the propagation of movement to the limbs, if the injury happened to occur in its path. Curiosity being thus awakened, numerous experiments were made, in order to ascertain the fact: and living animals were mutilated and tortured without mercy for the purpose of determining which function belonged to which root. It is extraordinary that even if humanity did not prevent this, common sense at least should not have interfered so far as to suggest that when the processes of the spine have been hacked open, when pain and loss of blood have disordered all the functions of nature, and when,happily for the poor animal, death is imminent,no rational conclusion can be formed as to the normal functions of the parts. * The controversy was long and hot; and many opinions were broached as to the functions of the anterior and posterior roots of the spinal nerves which subsequent and calmer investigation has greatly modified. The common sense view too has gained ground, and it is acknowledged that a careful register of the phenomena of disease, followed by a post-mortem examination, is generally more to be depended on than the experiments, so revolting to humanity, which were at first resorted to; but from which, nevertheless, different therorists drew different results, each in favor of his own especial view of the case.

* See Quain and Wilson's Anatomy of the Nerves, p. 35.

* "Direct experiments on the anterior and posterior columns of the cord are surrounded with difficulties which embarrass the experimenter and weaken the force of his inferences. The depth at which the cord is situate, in most vertebrate animals, its extreme excitability, the intimate connection of its various columns with each other, so that one can scarcely be irritated without the participation of the others, the proximity of the roots of the nerves to each other sufficiently explain the discrepancies which are apparent in the results of the various experiments which have been published. If the anterior fasciculi of the cord, observes Dr. Nasse, 'possess sensibility but only in a slight degree, the mere opening of the vertebral canal, and laying bare the cord, must cause such a degree of pain as would

14. Whilst the controversy was yet raging with a fierceness hardly befitting a scientific question, Dr. Marshall Hall suddenly stepped in,* and gave a new character to the inquiry. He proved that there were many actions which appear to be voluntary which nevertheless take place during a state of utter insensibility, or even, in some animals, as in

weaken or destroy the manifestation, &c." Todd and Bowman's Phys., vol. i. p. 317.

Alas! that this should have been only a late thought! too late to prevent the infliction of tortures which the mind shrinks from contemplating, and which I will not pain my readers by detailing.

* I give the name of this gentleman because he was the most active in drawing attention to phenomena, which, though they had been noticed by some others, had not been sufficiently considered.

+ The cerebral system of nerves conveys impressions from every part of the body to the brain, and the individual then feels them as sensations, and by the fibres of the same system, which pass from the brain to the muscles, the will acts upon them in producing voluntary motion. Now the brain is not in constant action, even in a healthy person; it requires rest: and during profound sleep it is in a state of complete torpor. Yet we still see those movements continuing which are essential to the maintenance of life, the breathing goes on uninterruptedly,liquid poured into the mouth is swallowed, and the position is

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