Baron Humboldt’s description of the mode of catching the Gymnotus, or Electrical Eel

Baron Humboldt’s description of the mode ofcatching the Gymnotus, or Electrical Eel.

While traversing the immense plains of theprovince of Caraccas, in order to embark at St. Fernando de Apure, and commence ourvoyage on the Orinoco, we stayed five daysat Calabozo, a small town situated, accordingto my observations, in 8° 56′ 56″ north lati-tude. The object of this visit was to studythe electric eels (Gymnoti,) an innumerablequantity of which are found in the neighbour-hood. Indeed I was assured, that near Uri-tuca a road, once much frequented, had beenentirely abandoned on account of these elec-tric fishes; travellers being obliged to ford astream in which a number of mules were an-nually drowned, stunned by the shocks theyreceived from the gymnoti.

In order to perform our experiments withmore precision, we were desirous of havingthe electric eels in the house which we inha-bited at Calabozo. Our host took all possi-ble pains to gratify our desires. He sentIndians on horseback to fish in the pools. Itwas easy enough to procure plenty of deadgymnoti; but an almost puerile fear prevent-ed the natives from bringing them alive. Wewere afterwards, it is true, convinced of thedifficulty of handling this fish whilst it stillretained all its powers: but the dread of thecommon people is the more extraordinary inthese countries, as they pretend that any onewith tobacco in his mouth may touch a gym-notus with impunity. If the Indian had fullconfidence in this preservative, which is alto-gether false, why did he not avail himself ofit to gain the ten francs which we had pro-mised for every living electric eel that wasbrought to us? The love of the marvellousis so great among the natives, that they oftenmaintain and spread abroad as facts what theythemselves are far from putting faith in. Itis thus that man thinks he must needs add tothe wonders of nature, as if nature was notof herself sufficiently mysterious, grand andimposing.

After three days of fruitless attempts in thetown of Calabozo, during which we receivedonly one eel alive, and that in a very weakstate, we resolved to transport ourselves tothe spot, and make our experiments in theopen air, on the banks of the pools in whichthe gymnoti abounded. We reached first alittle village called Rastro de Abaxo; thencethe Indians conducted us to Caño de Bera, amuddy stagnant pool of water, but surround-ed with a beautiful vegetation of the Clusiarosea, the Hymenea Courbaril, the large Indianfigs, and Mimosæ with odoriferous flowers.We were much surprised on being told thatthirty wild horses must be caught in theneighbouring savannahs, to serve for thefishery of the electric eels. The idea of thismode of fishing, which they call embarbascarcon caballos, (to stupify by means of horses,)is truly very odd, The word barbasco signi-fies the roots of Jacquinia, of Piscidia, or ofany other poisonous plant, by the contact ofwhich a great extent of water receives in aninstant the power of killing, or at least ofintoxicating or benumbing, the fishes. Thelatter rise to the surface of the water whenthey are poisoned in this way. As the horsesdriven here and there in a pool cause thesame effect with respect to the frightenedfishes, the natives, confounding cause andeffect, call the two modes of fishing by thesame name.

Whilst our host was explaining to us thisstrange mode of catching fish in this coun-try, the troop of horses and mules arrived.The Indians formed a sort of battue, and en-circling the poor quadrupeds closely on everyside, compelled them to enter the pool. Ican but imperfectly depict the interestingspectacle which the attack of the eels uponthe horses presented to us. The Indians,holding long canes and harpoons, place them-selves around the pool; some of them climbthe trees whose branches project over the surface of the water; and all of them by theirshouts and their weapons prevent the horsesfrom gaining the bank. The eels, confound-ed by the hubbub and splashing of the horses,defend themselves by the reiterated dischargeof their electric batteries.

For a long time they seem victorious overthe horses and mules; every where we seethe latter, stunned with the frequency andforce of the electric shocks, disappearing be-neath the water. Some of the horses recoverthemselves, and, despite the active vigilanceof the Indians, gain the bank; overcome byfatigue, and their limbs paralysed by the powerof the electric commotions, they lay out-stretched upon the earth.

How I wished that a clever painter couldhave seized the moment when the scene wasat its greatest animation. The groups of In-dians surrounding the pools,—the horses, withmane erect, and eyes of fright and pain,struggling to escape from the storm whichhad surprised them;—those yellow livid eels,like great aquatic serpents, swimming uponthe surface of the water, and pursuing theirenemy;—all these objects presented, in truth,a most picturesque ensemble. I rememberedthe superb painting which represents a horseentering a cavern and scared at the sight ofa lion! The expression of terror was notstronger than we witnessed in this unequalconflict.

In less than five minutes, two horses werealready drowned. The eel, being more thanfive feet in length, glides beneath the bodyof the horse or mule; it then gives a dis-charge from the whole length of its electricorgan. It attacks at the same time the heart,the digestive viscera, and above all the plexus of the gastric nerves. One cannot feel as-tonished, then, that the effect produced bythe fish upon a great quadruped much exceedsthat produced on man, which it only touchesby one of the extremities. I doubt, how-ever, that the gymnoti kill the horses imme-diately; I rather imagine that the latter, stun-ned by the electric shocks which they receivein rapid succession, fall into a profound le-thargy. Deprived of all sensibility, they dis-appear beneath the water, the other horsesand mules pass over their bodies, and a fewminutes suffice to make them perish.

After this commencement, I began to fearthat this conflict would terminate very tragi-cally. I did not doubt but that I should in alittle time see all the mules drowned. Wepay, however, only eight francs for each, ifthe master of it is known. But the Indiansassured us that the fishing would soon beover, and that it was only the first assault ofthe gymnoti that was formidable. In fact,whether it is that the galvanic electricity ac-cumulates during a state of rest, or that theelectric organ ceases to perform its functionswhen fatigued by too long usage, the eels,after a certain time, resemble discharged bat-teries. Their muscular motions continueequally lively, but they have no longer thepower of discharging very energetic shocks.When the conflict had lasted a quarter of anhour, the mules and horses seemed less alarm-ed; they did not erect the mane, their eye expressed less pain and terror; we saw themno longer fall over. On the other hand theeels, swimming half out of the water, andendeavouring to avoid the horses in place ofattacking them, in their turn approached to-wards the bank. The Indians assured us,that no horse is killed when driven two daysafterwards into the pool. These electricfishes require rest and abundant nourishmentto produce and to accumulate a great quan-tity of the galvanic electricity. We know,by the experiments that have been made uponthe torpedos (electric rays) of Italy, that oncutting or tying the nerves which go to theelectric organs, the functions of these partscease, as the movement of a muscle is sus-pended as long as the ligature of the mainartery or nerve remains. The organs of thetorpedo or gymnotus depend upon the nervoussystem and the vital functions: they are notmere electro-motive apparatuses, which at-tract from the surrounding bed of water theelectricity they have lost. One cannot, there-fore, be surprised that the power of the elec-tric shocks of the gymnoti depends upontheir health, and consequently upon rest,nourishment, age, and probably a great as-semblage of physical and moral conditions.

The eels, making towards the bank, aretaken with great facility. Small harpoons,attached to cords, are cast at them; the har-poon sometimes brings up two at a time. Bythis means they are drawn out of the waterwithout the cord, which is very dry and ofsome length, communicating the shock to theperson who holds it. In a few minutes fivelarge eels were on dry land. One might havecaught twenty, if as many had been wantedfor our experiments. Many were only slight-ly wounded in the tail; others severely in thehead. We were enabled to observe the na-tural electricity of these fishes, modified bythe different degrees of the vital force whichthey enjoyed. I shall describe in this me-moir not only the experiments made, in con-junction with M. Bonpland, on the gymnotitaken in our presence, but also those whichwe had an opportunity of making upon an eelof an enormous size, which we found in ourhouse on our return from Rastro de Calabozo.This latter had been caught in a net; it hadnot received any wound. Immediately onbeing drawn out of the water, it had beenput into the same tray in which it was broughtto Calabozo. Remaining thus in the samewater it was accustomed to, galvanic electri-city had not been altered. We shall see,however, in the course of this memoir, thatthe wounded gymnoti, that is to say, those ofless power, are much more instructive in theenquiry into galvanic phenomena than thevery active gymnoti, for many shades escapethe eye of the observer when the electric tor-rent takes as impetuous a course across goodconductors, as across those which are moreimperfect.

When one has seen the eels knock down ahorse, and deprive it of all sensibility, he isnaturally afraid to touch them the momentthey are brought out of the water. So strong,in fact, is this dread among the people of thecountry, that none of them could muster up resolution to disengage the gymnoti from thecords of the harpoon, or to transport themto the little holes filled with water which wehad made along the bank of the Caño deBera. It needed all our fortitude to receiveourselves the first shocks, which certainlywere not very agreeable. The most energe-tic surpassed in power the most painful elec-tric shocks I ever remembered to have re-ceived, accidentally, from a large and com-pletely charged Leyden jar. From that timewe readily conceived that, without doubt,there was no exaggeration in the story of theIndians, when they assert that persons whoare swimming are drowned when one of theseeels attacks them by the leg or the arm. Adischarge so violent is fully capable of de-priving a man for many minutes of all use ofhis limbs. If the gymnotus should glide alongthe belly or the chest, death might even fol-low instantaneously the electric shock; for,as we have before observed, the most nobleparts, as the heart, the gastric system, thecœliac plexus, and all the nerves that dependupon it, would at once be deprived of theirirritability. A feeble electricity augmentsthe vital forces,—a strong degree extinguishesthem entirely.—Voyage de Humboldt et Bon-pland.