To determine whether such a channel actually existed or not, Dr. Wollas ton introduced into the stomach three grains and a half of the salt called prussiate of potash; the presence of which, in almost all kinds of colourless fluids, is capable of detection to the utmost nicety, by mixing with them a small portion of solution of iron, the colourless compound being immediately marked with a blue tinge. The above quantity was given to a healthy person, about thirty-four years of age, and was repeated every hour to the third time. The natural secretion from the kidneys being tested every half hour, was found in two hours to be slightly dyed, and at the end of four hours to afford a deep blue. At this period, just one hour after taking the last dose, and when the blood-vessels might be supposed to be fully impregnated with the material, if it passed to the kidneys through this conveyance, blood was taken from the arm, and allowed to coagulate, so that the serum or limpid part of it might be fully separated. The presence of the prussiate was then endeavoured to be discovered, by means of the solution of iron, but without the least effect, for the serum still remained colourless. And in other experiments of a similar kind, made both by Dr. Wollaston and Dr. Marcet, it was satisfactorily ascertained that the prussiate of potash, though it found its way readily to the kidneys, did not exhibit any trace of its existence in the fluid of any other organ whatever, any more than in that of the blood; as the saliva, the mucus of the nostrils, or the limpid discharge produced by blisters. Mr. Home has since shown, that rhubarb introduced into the stomach in like manner finds a path to the kidneys, apparently without passing through the circulating system.* Mr. Home at one time suspected that the organ of the spleen afforded a passage from the stomach to the circulation of the blood in the cases before us, instead of the lacteal vessels, which immediately rise from the alimentary canal. This idea, he has, however, since relinquished as erroneous; but had even such a passage existed, it would not have answered the purpose; for it would only have conducted materials by another path to the blood; and the experiments of Dr. Wollaston have sufficiently proved, that the unknown channel, wherever it lies, has no connexion whatever with any part of the system of blood-vessels, or even with the common system of absorbent vessels and so far he seems to have disproved a previous theory of Mr. Charles Darwin upon this subject, which held, that the absorbent system might become the channel, by assuming a retrograde action. Such action, however, has never been established, and, independently of the experiments before us, it is rendered highly inconceivable by the known structure of the absorbent vessels themselves. The corollary, then, resulting from these observations, is, that in the animal system, as well as in inorganic nature, bodies in various instances act where they are not, and through channels of influence or communication, with which we are altogether unacquainted. The examples thus far offered, in regard to animals, I readily admit, are taken from different parts of the same individual frame: but as they are drawn from parts remotely situated, and whose intercourse, so far as we are able to trace it, is as much cut off as though they were of different frames, excepting, indeed, by a channel which does not show itself to be resorted to in the cases before us, I mean the blood; they may serve to lay a groundwork for our conceiving the possibility of a similar influence or association of action between different parts of different frames, or, which is the same thing, between living body and living body. I proceed, then, to offer examples of this latter kind of influence. The subject, I am aware, is not only of a very curious, but of a very delicate nature, The only mode by which the present writer can conjecture the possibility of these substances being conveyed to the kidneys by the course of the blood, and becoming manifest in their ordinary secretion, on the application of chemical tests, is, that they may be so minutely decomposed by the action of the blood while passing through it, as to be beyond the influence of any tests whatever; and that they only discover themselves in the renal secretion, in consequence of a peculiar attraction or affinity of the organ for such materials, and their being hereby thown off in a more concentrated form. But this explanation is, after all, merely conjectural.-See Study of Med. vol. v. p. 283, 2d edition. and requires to be handled with the greatest dexterity; nor do I know of any philosophical work to which we can turn as a proper beacon to direct us in our pursuit, and to determine where the boundary of sober judgment ceases, and that of imagination begins. Some of the instances I shall refer to may, perhaps, be denominated instinctive influences. I have no objection to the term; but the facts will remain as singular, and as little accounted for, as if no such term were in existence. Among quadrupeds, and, so far as we know of them, among amphibials, fishes, and insects, there exists but little attachment of the male to the female during the time of parturition, or to his own yg after the female has brought them forth. The seal-tribes, and especiay those of the trichecus Manatus, or lamantin, from which we have probably derived all the idle stories of mermen and mermaids, together with a few others, may, perhaps, be offered as an exception; for these, and especially the lamantin, form unions of single male with single female that continue through life, and live in distinct families with their offspring, till the last, acquiring maturity, leave their paternal home, and found similar families for themselves. Such, then, being the general fact with regard to other animals, whence comes it to pass that the males among the bird-tribes should evince, with a few exceptions, an attachment that is so rarely to be met with elsewhere? What is that wonderful power that rivets the greater number of male birds to female birds during the time of nestling and incubation; that impels them to take an equal part in constructing the nest, and stimulates them with feelings unknown at any other season? Whence is it that several of them, as the male raven (corvus Corax), divide the toil and time of sitting, and incubate the eggs by day as the female does by night? or, that others of them, leaving to their respective females the entire process of incubation, sooth them through the whole of this tedious period, often extending to not less than six or eight weeks, with their melodies from a neighbouring bush, and supply them with food with the utmost tenderuess and punctuality? Whence is it, more especially amid birds that feed their young with a viscid chyle or milk, secreted at that peculiar period in the crop or craw, that the crop of the male becomes enlarged and changed in its action, in the very same manner as that of the female, so as to enable him to divide the tender office of nursing, and to supply the young with an equal quantity of nutriment? In the body of the mother we can, perhaps, trace a series of actions which, if they do not give us a full insight into the cause of such a change, and such an additional function, at least prepare us to contemplate it with less astonishment; it is a change, in a very considerable degree, analogous to what occurs in the female frame of most other kinds and classes when similarly situated; and which is evinced in its highest and most beautiful perfection in our own race. But in the production of a similar change in the crop of the male pigeon, we meet with a fact altogether anomalous and alone: there is no connexion of organ with organ; no perceptible chain of actions that can have given rise to it: the frames of the individuals are distinct. It is a pure sympathy excited in one being by a peculiar change produced in the organization of another, and leading to a similar change in the being that is thus most wonderfully and inexplicably operated upon. Let us pass from the bird-tribes to fishes. There are various animals of this class that, on being touched, or even approached without being touched, are enabled to exhaust the irritable or sensorial power, or both together, of the hand or other limb that approaches them, so as to paralyze it and render it incapable of exertion. Such, especially, are those fishes which we denominate the torpedo-ray, and the electric eel or gymnote. Of these the former has been longest known to naturalists; for, in consequence of its being an inhabitant of the Mediterranean Sea, it is described both by Greek and Roman writers, who impute its distinctive faculty to magic; and conceive that the animal has a power, not only of concentrating this magical energy at option, but if seized hold of by a fishing-hook, of impelling it through the whole length of the hook, line, and rod, to the arm of the angler, and hence by palsying his arm, of effecting his escape. So Oppian in Greek verses, which I will take leave thus to translate : The hook'd torpedo, with instinctive force There may, perhaps, be some exaggeration in this description; but there are not wanting naturalists of modern times who contend that the torpedo is able to throw his benumbing influence to this extent and in this manner. This influence, moreover, is altogether voluntary; and hence the animal will sometimes allow himself to be touched without exerting it. He occasionally loiters on the moist sands of the shore after the tide has retreated, burying himself under the sand by a brisk flapping of his fins, which serves to fling this material over him; and in this state he is said to inflict at times, even through the sand that covers him, a torpor so severe as to throw down the astonished passenger that is inadvertently walking over it. We now know something of the medium through which this animal operates, and have no difficulty in referring it to an electric or Voltaic aura, and can even trace a kind of Voltaic apparatus in its structure. Yet, before the laws or power of electricity or Voltaism were known, and, consequently, before the medium by which they act was followed up, which to this hour, however, is only known by its results (for it has never been detected as an object of sense), it is not to be wondered at that so mysterious an energy, operating or ceasing to operate at the option of the animal, and occasionally operating at a distance from the individual affected, should be regarded as a species of magic or incantation. The Voltaic power of the electric eel or gymnote, is, however, more obvious and effective than that of the torpedo: the gymnote making a sudden and concentrated assault by shocks, of less or greater violence, as though from a more highly-charged battery; and the torpedo, by a numbness or torpor, whence, indeed, its name, produced by small but incessant vibrations of Voltaism, seldom, excepting in severe cases, amounting to the aggregation of shocks, and precisely similar to what is felt in a limb upon applying to it a great multitude of weak strokes, rapidly repeated from a small battery or Leyden phial. Yet even the peculiar properties of the gymnote were received with the greatest skepticism for nearly a century after their first discovery; which, as this fish is almost exclusively a native of the warmer seas and rivers of Africa and America, did not take place till the middle of the seventeenth century. They were first pointed out to the French Academy in 1671, by M. Richer, one of the travelling professors sent out by the Academy to conduct certain mathematical observations in Cayenne; but were not generally credited till the concurrent experiments of M. Condamine, Mr. Ingram, Mr. Gravesend, and other celebrated natural historians, set every doubt at rest, about a century afterward. The more formidable power of the electric gymnote enables it, upon the authority of almost every experimentist, to give not only severe shocks, both in the water and out of the water, when in actual contact with another animal, but to convey them, as we have just observed that the torpedo is said to do, though upon doubtful testimony, through long rods or poles. It is highly probable, however, that such poles must first be wetted with water; for both the gymnote and the torpedo are found to be limited to precisely the same conducting and non-conducting mediums as are met with in common electricity. In these cases we trace something of the medium by which the irritable or * Alieut. i. 412. sensorial power is exhausted. There are various other cases, however, in which, to this moment, we are as ignorant, and as little capable of tracing it, as mankind must have been in regard to the animals before us, antecedently to a discovery of the electric aura. And I here particularly allude to the torpid effects produced upon poisonous serpents and scorpions in Africa and America, on their being handled by persons of two different descriptions; the one possessing this torpifying power naturally and hereditarily, and the other acquiring it by artificial preparation; such as chewing the roots or other parts of certain plants, rubbing them in their hands, or bathing the body in aqueous infusions of them, and thus impregnating the body of the operator with their virtues. There appears to be no country in the world so much infested with serpents of this kind as the ancient Cyrenaica, or that part of Africa which lies northward of the great desert of Sahara. Among the different tribes that formerly inhabited this region, one of the most celebrated was the Psylli; and as this tribe seems to have been in full possession of this power, either from art or nature, and to have given the strongest and most extraordinary proofs of its having possessed it, all persons capable of exerting a similar effect were denominated Psylli by the Greek and Roman writers. And hence Plutarch tells us, that when Cato pursued his march through the Cyrenaic desert in search of Juba, he took with him a variety of these Psylli to suck out the poison from the wounds of such of his soldiers as should be bitten by the numerous serpents of the country. It appears most probable that the Psylli were not naturally protected against this venom, but from long and skilful practice were acquainted with the virtue of those plants which, as I have just hinted, answer both as a preservative against the bite, and as an antidote after the bite has been inflicted: and, being strongly addicted to divination or pretended magic, as all the historians who have given us any account of them affirm them to have been, affected to derive their power of subduing poison from this preternatural source alone, and inculcated the belief that they could only exercise it, by muttering or chanting some potent verse or spell over the person who was affected. And hence the disarming a serpent of his capacity of poisoning, or disarming the poison itself of its deadly effect after a wound had been received, was denominated charming or incantation. So Silius Italicus,* in allusion to the Psylli, or their neighbours, the Marmarides, lib. iii. : This sort of power, derived from art or nature, and probably originating in this quarter of the world, appears to have been known in the remotest ages, and to have been uniformly ascribed to the same influence of certain magical words or verses chanted, or uttered in recitative; and it appears also to have been very generally conjectured, that there exists some kinds or species of poisonous serpents that are capable of shutting their ears against the sounds thus uttered, and that will not hearken to or be charmed by the voice of the enchanter, however skilful the enchantment. The sacred books abound in allusions to this popular tradition ;† they are equally to be met with in the writings of the Greek and Roman poets, and even in the Sanscrit moralists, as, for example, in the Hitopadesa of Vishnusarman, probably of a higher antiquity than the Psalmist himself, who tells us in his book of aphorisms, that "as a charmer draweth a serpent from his hole, so a good wife, taking her husband from his place of torture, enjoyeth happiness with him."‡ * See also Virgil, Æn. vii. 753, in which he ascribes the salutiferous power both to the song and touch of the enchanter. Vipereo generi et graviter spirantibus hydris † Ps. Iviii. 5, as also Jer. viii. 17, Deut. xviii. 11. Transl. of Sir William Jones. There are some philosophers and historians, who have ventured to disbelieve that any such extraordinary power has ever been possessed by any people. The very cautious writers of the Ancient Universal History express no small degree of skepticism upon this point :* and M. Denon, one of the chief of the literati that accompanied Buonaparte to Egypt, has been bold enough to laugh at the assertion, and to regard every pretension to such a power as a direct imposture. He offers, however, no sufficient ground for his ridicule, and is flatly contradicted by the concurrent testimony of all the best travellers, both to Africa and South America. Mr. Bruce is very full and very explicit upon the subject. He distinctly states, from minute personal observation, that "all the blacks in the kingdom of Sennaar, whether Funge or Nuba, are perfectly armed (by nature) against the bite of either scorpion or viper. They take the cerastes (or horned serpent, being the most common, and one of the most fatal of all the viper tribes) in their hands at all times, put them in their bosoms, and throw them to one another, as children do apples or balls;" during which sport the serpents are seldom irritated to bite, and when they do bite, no mischief ensues from the wound. The Arabs of the same country, however, he tells us as distinctly, have not this protection naturally; but from their infancy they acquire an exemption from the mortal consequences attending the bite of these animals, by chewing a particular root, and washing themselves with an infusion of particular plants in water. The Nuba and Funge, however, or those who are preserved naturally from the bite and venom of the viper and scorpion, are also highly skilful in the knowledge and application of these roots, and other parts of plants, to those who have no natural protection or charm. Mr. Bruce has given a particular account of several of these plants, some of which seem only capable of acting against the power of the serpent, others only against that of the scorpion, and a third sort against both. And in either instance, where they secure against the bite or sting, and thus operate as a preventive or prophylactic, they also secure equally against the poison, when introduced into the system by a wound, and thus operate as an antidote. In South America the natural charm does not seem to be possessed by any tribe: but the artificial charm, obtained by the use of peculiar plants, is known as extensively, and employed as successfully, as in Africa, and is found to possess the same double virtue of an antidote and a preventive. One of the most satisfactory accounts of this singular fact is contained in a memoir drawn up, in 1791, by Don Pedro d'Orbies y Vargas, a native of Santa Fe, which details a long and accurate list of experiments which he instituted to ascertain it. The plant chiefly employed by the American Indians, he tells us, is denominated in that part of the world vejuco de guaco, guaco-withy, from their having first observed that the bird of this name, or, as Catesby calls it, the serpent-hawk, usually sucks it before it attacks poisonous serpents, and then attacks them without mischief. Prepared by drinking a small portion of the juice of this plant, and inoculating themselves with it also, by rubbing it upon three small punctures in the hands, breast, and feet, and thus impregnating the body with its virtues, Don Pedro himself, and all his domestics, were accustomed to venture into the open fields, and fearlessly seize hold of the largest and most venomous serpents. It was scarcely ever that the animal thus charmed or fascinated had power to bite, and when he did so, the wound produced was slight and of no consequence. M. Acrell, in the Amonitates Academicæ, after mentioning the same plant, tell us that the senega is possessed of a like power.§ Of the truth of the fact, therefore, thus confirmed by the most trusty travellers and historians, in different quarters of the world, there can be no doubt; and it adds to the facility of believing it to find that other animals besides men are possessed of a similar power. Thus the conder and the wild boar feed harmlessly on the rattlesnake, which appears to offer no resistance to Travels, Appendix, p. 303. Vol. iii. p. 491, Appendix. It appears to be the ophiorrhiza Mungos of Linnæus. |