THE NATURALIST. ELECTRIC FISHES.

Otago Witness, Issue 2671, 24 May 1905, Page 68

THE NATURALIST.

ELECTRIC FISHES.

THEY POSSESS THE POWER OP GIVING SEVERE SHOCKS.

There is at present residing in New Yoik a iran who has devoted the greater part of his life to the business of collecting natural history specimens for the large museums of the world, notably the National Museum at Washington, the British Museum of London, and the Natural History Museum of New York. On account of advancing age he retired from active life several years ago. Many and are the experiences he has undergone in various parts of the world, and there is nothing delights him more than to recount these to an appreciative listener. "I saw/ he said in conversation the other day, " a curious thing once while collecting in Africa in the neighbourhood of Old Calabar River. I had secured quarters in a small native village on the river bank, and one morning as I was dressing 1 heard a most unearthly yelling outside. Hurrying to the door and looking out, I found it proceeded from a little naked hoy belonging to the hut just across from mine. Discovering at a glance that the child was not being tortured to death, as I had at first supposed from the noise he made, I looked to see the cause for his outcry. A large tub was standing in front of the hufc, and every few minutes the child would put his hand into this, immediately afterward jumping back and emitting another squeal. While I was standing there and wondering what was the matter with him his mother came out of the hut, and, picking him up in her arms, soused him into the tub, causing him to emit the most earsplitting howls and make frantic efforts to clamber out. Curious to learn the cause of this strange proceeding I crossed over and looked into the tub, from which the mother had by this time removed the boy, and was surprised to see swimming around iv it a fish about a foot and a-half in length. Looking closer at it I suddenly recognised it to be what the natives called a thunder fish, and which is known to scientists as the malapterus, one of the slidride, or catfishes. " This fish possesses the remarkable property of being able to give an intense electric shock to any animate body which it touches, and on inquiry of the mother I found that it was a common custom with them whenever a child was ailing to secure one of these fishes and compel the little one to play with, it, or place the sick one in the tub so ' that it would come in contact with the live wire — I should say livo fish. " Unlike most of the electric fishes, which have their electric organ situated in a mas 3 of muscle, this animal has his in his skin, which is quite thick, and throughout whioh ars found sometimes as many as four million plates, arranged essentially as in a galvanic pile. "While on this subject of electric fishes I must tell you about a curious thing I saw once while collecting specimens along one of the tributaries of the Orinoco, in .South America. I had sat down to rest on the fallen trunk of a tree, half of which was lying in the water, and was half asleep, when* a slight splashing along the bank attracted ,my notice, and the collecting instinct, which is ever strong, caused' me at once to become all attention. Casting my eye along the water's edge I noticed the head of a small animal, which had evidently just plunged into the water, and was swimming towards the sunken end of the log upon which I was sitting. Just as he had covered about two-thirds of the distance I was surprised to see a loipg, slender,^ white body rise in tihe air alongside the swimmer, and apparently coil itself around the animal in less time than I take to tell it. At this moment the hitherto unsuspecting animal saw its danger, but it was then too late, for I saw the coil tighten, and with a frantio yell the animal rolled over on its back as though a bolt of lightning had struck it Very much surprised at such a remarkable occurrence, I at once picked up my shot-gun, and filled the animal's snakelike body with fine shot. ' I then plunged in and brought both ashore, and saw then that the animal had virtually been killed by a bolt of lightning, for the creature which had attacked it was the gymnotus, or electric eel, which is quite common in those waters.

" The gymnotus is probably the bestknown of the electric fishes. It possesses four batteries, which extend from behind the pectoral, or forward, fins to the extremity of tne tail. The batteries consist of a number of piles placed horizontally in a direction from head to tail, and have been aptly compared to galvanic troughs. The current passes from before backward, and, remarkable to relate, passes through the animal's own brain.

" You have doubtless heard how 1 the Indians dare not cross South American streams which are infested by these creatures, and therefore adopt the expedient of driving in their horses, upon which the eels fasten and exhaust themselves in a vain effort to kill them. When exhausted they are unable, through failure of the central nerve organ, to discharge the organ, and the Indians then cross in safety. "Another electric fish is the torpedo, a flat fish closely allied to the family of skates and rays, and often termed the electric raj. I haye caught many of these in

the waters surrounding Key "West, Fla., and in the West Indies. The urchins of Key West frequently catch them, and take great delight in persuading unsuspectingtourists lo touch them in order to see the fish jump, with the resijlt that the tourist generally does the jumping. "This animal is the only one with electrio organs which exercise all the other known powers of electricity; they render the needle magnetic, decompose chemical compounds, and emit the spark. " The animal sometimes attains to a. width of from 2ft to 3ft, and specimens of that size are competent to disable by a single discharge a full-grown man. The creature has two batteries, which occupy the two spaces between the pectoral fins, the head, and gills. Each battery consists of a quantity of prisms, which vary m nuniber from 400 to upward of 1000, depending upon the age of the animal. According to observation the upper surface of the fish is positive and the abdominal surface negative. The animal instinctively elevates or arranges its margin, so as to adjust the direction of its currents to the position of the object through which it wishes to pass them. It gives a number of intermittent discharges, which it can keep up for several minutes, which time is long enough to enable it to stun or kill small fish in its neighbourhood, which it is then able to eat at its leisure. It is also sufficient to provide a formidable weapon for defence from the attacks of enemies who might otherwise prey upon it. In order to deliver a shock the torpedo must complete the galvanio circuit by touching the animal attacked at two distinct points, either directly or through the medium of some conducting body. It is said that a painful sensation may be produced by a discharge conveyed through the medium of a stream of water."— New York Sun.