G Y M N O T U S. 



the tail ; and the two are separated from each other 

 by the muscles of the back. The small ones are 

 under these, and extend nearly the same length, but 

 are altogether much smaller, and very slender toward 

 the tail. The two smaller organs are separated from 

 each other along the mesial line by the bones of the 

 anal fin, and the muscles which give motion to that 

 fin ; and there are also small muscles between those 

 small organs and the skin. The larger ones are sepa- 

 rated from the skin, or rather united to it by loose 

 cellular tissue only, so that upon the skin being re- 

 moved they are seen at once. The organic part of 

 this singular apparatus consists of a vast assemblage 

 of cells, which fancy can easily conceive to have 

 some analogy to the phials in an electric battery, or 

 rather perhaps to the divisions of a galvanic one, for 

 the cells are, like those divisions, filled with a liquid. 

 The partitions of the cells consist of flat longitudinal 

 septa, crossed by nearly similar partitions. The 

 septa extend nearly the whole length of the fish, 

 and have their breadth not much less than half the 

 diameter of the body. They consist of thin and deli- 

 cate membranes. These septa are, in the large organs, 

 nearly straight and parallel to each other for the 

 greater part of their length, and in consequence of 

 this they are^not all the same length. Neither are 

 they at the same distance apart throughout the whole 

 of their breadth. They are widest externally, and 

 converge toward the interior. Whether the number 

 is the same in large and small specimens has not 

 been clearly ascertained ; but such may be the case. 

 In a fish two feet four inches long there were thirty- 

 four at the broadest part, and they were nearly half 

 an inch apart externally. In the smaller organs the 

 septa are curved or serpentine, and much nearer each 

 other ; so that though only half an inch in breadth in 

 the specimen alluded to, this organ contained forty. 

 The space between every two septa appears to be a 

 distinct organ ; and these organs are divided cross- 

 wise by remarkably thin partitions, which are near to 

 each other ; so that Dr. Hunter counted two hun- 

 dred and forty in an inch in length. The minute 

 cells formed by those transverse partitions are filled 

 with a fluid ; but what the particular nature of this 

 fluid is in the living animal, or how it acts upon the 

 partitions, so as to produce the electric energy, has 

 not been, and possibly cannot be ascertained. Still 

 there is a wonderful resemblance between those or- 

 gans and galvanic troughs ; but the incomprehensible 

 part of the matter is, how the animal contrives to 

 make those troughs act. If the animal is touched 

 with one hand only, that is, if it is touched only in 

 one place, no shock is felt ; but if it is touched at two 

 places considerably apart from each other, the shock 

 is very violent. Humboldt states that he felt more 

 pain from the shock of a large gymnotus than from 

 that of a powerful electric spark ; and when he placed 

 both feet upon one newly out of the water, at some 

 distance from each other, he received a most violent 

 shock, and felt pain for the rest of the day, not only 

 in his legs, but in almost every joint of his body. 



It appears, from the experiments of Dr. William- 

 son, Mr. Walsh, and many others, that nearly the 

 same substances are conductors and non-conductors 

 of the shock of the gymnotus, as are conductors and 

 non-conductors of common electricity. It may with 

 perfect impunity bo touched with a glass rod, or 

 with the hand wrapped up in a dry silk handkerchief ; 

 but metals, water, and all moist bodies, conduct it 



readily. The shock is conveyed to a considerable 

 distance from the animal, so that it can strike the 

 smaller fishes dead, or, at all events, deprive them of 

 motion at the distance of fifteen feet. One of the 

 experiments made by Dr. Williamson is worthy of 

 mentioning. He took a common cat-fish, which is 

 a very vigorous fish, put it into the water, and 

 placed his hand in the water, watching what would 

 occur. The gymnotus swam up to the cat-fish, but, 

 in the first instance, turned away without doing 

 anything. It speedily came back, however, and dis- 

 charged its battery at the cat. While it did so, the 

 Doctor felt a severe shock in his fingers, and the cat 

 turned on its belly, and remained motionless. With 

 several other fishes the result was similar ; but, though 

 stunned, it does not appear that they were killed, or 

 even received any permanent injury, for, when in- 

 stantly put into water apart from the gymnotus, they 

 speedily recovered. Hence it is probable that the 

 shocks given by this fish serve only to benumb its 

 prey until it can swim up and devour them. In- 

 stances are mentioned of fishes of this formidable 

 genus of much greater dimensions than those to 

 which we have alluded ; and the Indians say that 

 swimmers are often drowned by the stroke of a large 

 gymnotus, and that the most powerful quadrupeds 

 share the same fate. 



That the shocks are voluntary on the part of the 

 animal, that is, given or not given, according as it is 

 disposed, is a proof that, though the electric battery 

 is a mechanical or organic structure, the working of 

 it is a function of life. This is farther proved by the 

 fact, that, when these fishes have been provoked, and 

 made to discharge their batteries repeatedly, until 

 they are exhausted, they may be taken in the hands 

 with little more danger than any other fish, for it 

 appears that the electric organs take some time to 

 recover their tone. " In America," says Humboldt, 

 " they take advantage of this interval, and catch 

 these fishes with but little risk. They force wild 

 horses to enter the ponds inhabited by the electric 

 eels. These unfortunate quadrupeds receive the 

 first discharges ; stunned and overthrown, they dis- 

 appear under the water, arid the fishermen take pos- 

 session of their assailants either with their nets or 

 with the harpoon. The combat is finished in about 

 a quarter of an hour." 



The water in which Humboldt saw experiments 

 made on those eels was of a much higher temperature 

 than the water of Europe in the open air ; and 

 Humboldt rationally concludes that the inferior tem- 

 perature is the cause of the weakened power in those 

 individuals which have been tried in Europe. The 

 gymnotus is not the only electric fish. That power 

 in the torpedo has been known from remote anti- 

 quity ; and it is also possessed by a species of Silurus, 

 by one of Trichmrus, and by one of Tctraodon. In 

 all (notices of which will be found in their respective 

 places), the organs appear to be substantially the same, 

 but there appears to be none which in the power of 

 its shocks comes nearly up to the gymnotus. The 

 following account, by Humboldt, of the method of 

 taking the gymnotus, is so characteristic and so well 

 told, that we shall make no apology for laying it 

 before our readers : " Having," says Humboldt, 

 " remained for three days to no purpose in the town 

 of Calabozo, and received but a single eel, and that 

 rather weak, we resolved to proceed to the banks of 

 those pools in which gymnoti abound, and make our 



