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  • German Naturalists, Electric Eels and Horse Fishing December 8, 2010

    Author: Beach Combing | in : Modern , trackback

    Beachcombing mixes and matches his posts. If Beachcombing gets carried away with a theme – he has to confess to an Atlantis itch this week – then he tries to let at least a few days pass before he returns to that subject. However, every so often the excitement gets too much for him and he returns ‘like a dog to its vomit’ to an individual or period that particularly interest him. Cue the entrance of the nineteenth-century German naturalist Alexander von Humboldt whom we last saw, four days ago, feeding dogs to crocodiles from the top of a Cuban wardrobe. This time Alex is in Calabozo in the lower Orinoco and he is just about to make his first acquaintance with electric eels.

    I was impatient, from the time of my arrival at Cumana, to procure electrical eels. We had been promised them often, but our hopes had always been disappointed. Money loses its value as you withdraw from the coast; and how is the imperturbable apathy of the ignorant people to be vanquished, when they are not excited by the desire of gain?  The Spaniards confound all electric fishes under the name of tembladores. There are some of these in the Caribbean Sea, on the coast of Cumana. The Guayquerie Indians, who are the most skilful and active fishermen in those parts, brought us a fish, which, they said, benumbed their hands. This fish ascends the little river Manzanares. It is a new species of ray, the lateral spots of which are scarcely visible, and which much resembles the torpedo. The torpedos, which are furnished with an electric organ externally visible, on account of the transparency of the skin, form a genus or subgenus different from the rays properly so called.  

    In the early nineteenth-century electricity was still magically new and  getting a shock had a novelty value all of its own to Alex and his travelling companion Bonpland.

    Alex, in fact, insisted on handling these ‘torpedos’ himself but was disappointed by the low intensity of the charge so he set about improving the sting  ‘galvanizing the animal by the contact of zinc and gold’.

    The shock increased but was still unimpressive. However, help was on the way. Humboldt was finally introduced to the biggest stingers of all, the gymnoti.

    Our hero’s experiments with these creature were dramatic and foolhardy: so much so that Beachcombing – who is reduced to a gibbering wreck by the thought of an electric shock – found himself shouting ‘don’t do it, Alex!?

    It would be temerity to expose ourselves to the first shocks of a very large and strongly irritated gymnotus. If by chance a stroke be received before the fish is wounded or wearied by long pursuit, the pain and numbness are so violent that it is impossible to describe the nature of the feeling they excite. I do not remember having ever received from the discharge of a large Leyden jar, a more dreadful shock than that which I experienced by imprudently placing both my feet on a gymnotus just taken out of the water. I was affected during the rest of the day with a violent pain in the knees, and in almost every joint. To be aware of the difference that exists between the sensation produced by the Voltaic battery and an electric fish, the latter should be touched when they are in a state of extreme weakness. The gymnoti and the torpedos then cause a twitching of the muscles, which is propagated from the part that rests on the electric organs, as far as the elbow. We seem to feel, at every stroke, an internal vibration, which lasts two or three seconds, and is followed by a painful numbness. Accordingly, the Tamanac Indians call the gymnotus, in their expressive language, arimna, which means something that deprives of motion.

    In fact Alex was reminded of earlier experiments with electricity in which he had indulged.

    The sensation caused by the feeble shocks of an electric eel appeared to me analogous to that painful twitching with which I have been seized at each contact of two heterogeneous metals applied to wounds which I had made on my back by means of cantharides. [wth!] This difference of sensation between the effects of electric fishes and those of a Voltaic battery or a Leyden jar feebly charged has struck every observer; there is, however, nothing in this contrary to the supposition of the identity of electricity and the galvanic action of fishes. The electricity may be the same; but its effects will be variously modified by the disposition of the electrical apparatus, by the intensity of the fluid, by the rapidity of the current, and by the particular mode of action.

    Yet not withstanding the evident pain Alex and his friend Bonpland were like two little boys in a sand pit, loving every minute of it.

    Beachcombing imagines them provoking a shock and then walking over to write down their results while the locals looked on stupified.

    When M. Bonpland held [the eel] by the head, or by the middle of the body, while I held it by the tail, and, standing on the moist ground, did not take each other’s hand, one of us received shocks, which the other did not feel. It depends upon the gymnotus to direct its action towards the point where it finds itself most strongly irritated. The discharge is then made at one point only, and not at the neighbouring points. If two persons touch the belly of the fish with their fingers, at an inch distance, and press it simultaneously, sometimes one, sometimes the other, will receive the shock. In the same manner, when one insulated person holds the tail of a vigorous gymnotus, and another pinches the gills or pectoral fin, it is often the first only by whom the shock is received. It did not appear to us that these differences could be attributed to the dryness or moisture of our hands, or to their unequal conducting power… Resinous substances, glass, very dry wood, horn, and even bones, which are generally believed to be good conductors, prevent the action of the gymnoti from being transmitted to man. I was surprised at not feeling the least shock on pressing wet sticks of sealing-wax against the organs of the fish, while the same animal gave me the most violent strokes, when excited by means of a metallic rod. M. Bonpland received shocks, when carrying a gymnotus on two cords of the fibres of the palm-tree, which appeared to us extremely dry. A strong discharge makes its way through very imperfect conductors. Perhaps also the obstacle which the conductor presents renders the discharge more painful. I touched the gymnotus with a wet pot of brown clay, without effect; yet I received violent shocks when I carried the gymnotus in the same pot, because the contact was greater.

    However, Beachcombing has still not got to the most remarkable part of the account: how Alex actually captured the gymnoti. Beachcombing will not be going anywhere near running water for a while, though he would have loved to have seen a video of ‘horse fishing’.

    We at first wished to make our experiments in the house we inhabited at Calabozo; but the dread of the shocks caused by the gymnoti is so great, and so exaggerated among the common people, that during three days we could not obtain one, though they are easily caught, and we had promised the Indians two piastres for every strong and vigorous fish. This fear of the Indians is the more extraordinary, as they do not attempt to adopt precautions in which they profess to have great confidence. When interrogated on the effect of the tembladores, they never fail to tell the whites, that they may be touched with impunity while you are chewing tobacco. This supposed influence of tobacco on animal electricity is as general on the continent of South America, as the belief among mariners of the effect of garlic and tallow on the magnetic needle.  

    In any case, Alex was not to be distracted. He was soon leading a native party in search of his prey. But for once the locals had more efficient and more dramatic efforts than any that he could dream of.

    Impatient of waiting, and having obtained very uncertain results from an electric eel which had been brought to us alive, but much enfeebled, we repaired to the Cano de Bera, to make our experiments in the open air, and at the edge of the water. We set off on the 19th of March, at a very early hour, for the village of Rastro; thence we were conducted by the Indians to a stream, which, in the time of drought, forms a basin of muddy water, surrounded by fine trees the clusia, the amyris, and the mimosa with fragrant flowers. To catch the gymnoti with nets is very difficult, on account of the extreme agility of the fish, which bury themselves in the mud. We would not employ the barbasco, that is to say, the roots of the Piscidea erithyrna, the Jacquinia armillaris, and some species of phyllanthus, which thrown into the pool, intoxicate or benumb the eels. These methods have the effect of enfeebling the gymnoti. The Indians therefore told us that they would ‘fish with horses’, embarbascar con caballos [excite with horses]. We found it difficult to form an idea of this extraordinary manner of fishing; but we soon saw our guides return from the savannah, which they had been scouring for wild horses and mules. They brought about thirty with them, which they forced to enter the pool.  

    Beachcombing cannot go on without saying that horse lovers should probably totter off now and polish their saddles. We’ll meet again this time tomorrow with happier subject matter – likely the dome of St Paul’s.

    The extraordinary noise caused by the horses’ hoofs, makes the fish issue from the mud, and excites them to the attack. These yellowish and livid eels, resembling large aquatic serpents, swim on the surface of the water, and crowd under the bellies of the horses and mules. A contest between animals of so different an organization presents a very striking spectacle. The Indians, provided with harpoons and long slender reeds, surround the pool closely; and some climb up the trees, the branches of which extend horizontally over the surface of the water. By their wild cries, and the length of their reeds, they prevent the horses from running away and reaching the bank of the pool. The eels, stunned by the noise, defend themselves by the repeated discharge of their electric batteries. For a long interval they seem likely to prove victorious. Several horses sink beneath the violence of the invisible strokes which they receive from all sides, in organs the most essential to life; and stunned by the force and frequency of the shocks, they disappear under the water. Others, panting, with mane erect, and haggard eyes expressing anguish and dismay, raise themselves, and endeavour to flee from the storm by which they are overtaken. They are driven back by the Indians into the middle of the water; but a small number succeed in eluding the active vigilance of the fishermen. These regain the shore, stumbling at every step, and stretch themselves on the sand, exhausted with fatigue, and with limbs benumbed by the electric shocks of the gymnoti.  In less than five minutes two of our horses were drowned. The eel being five feet long, and pressing itself against the belly of the horses, makes a discharge along the whole extent of its electric organ. It attacks at once the heart, the intestines, and the caeliac fold of the abdominal nerves. It is natural that the effect felt by the horses should be more powerful than that produced upon man by the touch of the same fish at only one of his extremities. The horses are probably not killed, but only stunned. They are drowned from the impossibility of rising amid the prolonged struggle between the other horses and the eels.  We had little doubt that the fishing would terminate by killing successively all the animals engaged; but by degrees the impetuosity of this unequal combat diminished, and the wearied gymnoti dispersed. They require a long rest, and abundant nourishment, to repair the galvanic force which they have lost. The mules and horses appear less frightened; their manes are no longer bristled, and their eyes express less dread. The gymnoti approach timidly the edge of the marsh, where they are taken by means of small harpoons fastened to long cords. When the cords are very dry the Indians feel no shock in raising the fish into the air. In a few minutes we had five large eels, most of which were but slightly wounded. Some others were taken, by the same means, towards evening.   

    Alex writes  that the Indians found that when they horse fished over two days no steeds were killed on the second day. He also tells us that he left Calabozo ‘on the 24th of March, highly satisfied with our stay, and the experiments we had made on an object so worthy of the attention of physiologists’.

    Beachcombing found himself wondering about other early (Mediterranean?) encounters with electric eels? There must have been some. drbeachcombing AT yahoo DOT com

    Thanks again to Ricardo R.!