28 



SCIENCE. 



The first attempts at solution given in regard to this in- 

 quiry were of a singularly mistaken character. It has- al- 

 ready been said that Redi designated the electric organs 

 as falciform muscles or bodies. This unintentional com- 

 parison of the electric organs with muscles has played an 

 important, though by no means wholesome, part in the his- 

 tory of electric fish. 



With that broad comprehension, that massive reproduc- 

 tion which subordinate intellects often accord to the mas- 

 ter's ideas, Redi's direct successor and pupil, Lorenzini, 

 plainly indicated the electric organs as "falciform mus- 

 cles," thus entirely overlooking his teacher's apt precaution 

 on this point. And from Lorenzini every anatomist of the 

 following century calls these organs distinctly, and unal- 

 terably muscles, although this appellation is completely 

 voluntary, and notwithstanding the fact that the electric 

 organs, outwardly as well as inwardly, are totally unlike 

 muscles of any kind. 



If these organs, however, were muscles, it was but 

 natural that effects analogous with those produced by 

 muscles should be ascribed to them. There followed, con- 

 sequently, a purely mechanical theory respecting the action 

 of the organs, which was best set forth by Borelli, in 1685. 

 His opinion was that they contracted several times in quick 

 succession, thus giving a number of violent repulsions to 

 the object brought in contact. This, he thought, was fol- 

 lowed by a cramp or spasm of the same nature as that 

 experienced by a person who strikes his elbow sharply. 

 This theory met with universal applause. The most prom- 

 inent natural investigators, Linne, Reaumur and Hallere 

 agreed perfectly with Borelli, and we may say that until 

 the year 1750 the idea was recognized everywhere as the 

 only possible and complete explanation ever given. 



From the time of Redi to Reaumur the investigators 

 limited their experiments to the electric fish most accessi- 

 ble to them — the torpedo. The electric silurus of Africa 

 is scarcely mentioned, and if spoken of at all, it is merely 

 to mistake it for, or identify it with, the torpedo. How- 

 ever, during this period the third and last known electric 

 fish was discovered — the electric eel {gymnotus elcctrzcus) 

 — found in South American rivers, and possessing the 

 greatest bodily dimensions and the most powerful electric 

 properties of any. 



The first news of the gymnotus reached Europe about 

 the year 1672. Later, Alexander von Humboldt made the 

 fish famous, by describing in his book of travels, its fierce 

 struggles with horses. Humboldt tells us that the name 

 " Arimua," given to the eel by the South American In- 

 dians, denotes a creature that deprives of motion. He also 

 states that in former times the gymnotus was used as a 

 cure for paralysis. We may judge of the tremendous vio- 

 lence of the eel's electric discharges by quoting a fact re- 

 lated by Humboldt. 



"On one occasion the inhabitants of a certain town were 

 obliged to turn a street in an opposite direction because 

 the electric eels had increased to such an extent in the 

 rivers that every year they killed quantities of mules which 

 were accustomed to wade through the water heavily 

 laden." 



However, before more complete information concerning 

 the gymnotus could reach Europe, the youthful study of 

 electricity had undergone an important modification which 

 was destined to bear direct influence upon the theory re- 

 garding electric fish. The discovery of the Leyden jar 

 O745), spread through the world, and attracted universal 

 attention. Experiments were made in all parts of the 

 country, and everyone was anxious to learn the effects of 

 this new natural force by his own experience and sensa- 

 tions. 



Under these circumstances, it is not surprising that 

 Adamson, who had studied the effects of the Leyden jar 

 in Paris, on becoming acquainted with the electric eel in 

 Senegal (1751), compared the latter with the former, and 

 remarked that the shocks could be communicated like 

 electricity through an iron wire. Dutch investigators state 



the same thing in regard to the gymnotus. Its electric 

 shocks can be conducted through a chain composed of 

 several persons, but it is maintained that only the electric 

 conductors transmit the shock, while insulators can touch 

 the fish without any effect being perceived. 



Nevertheless, serious doubts arose concerning the cor- 

 rectness of this new theory, until the year 1772, when John 

 Walsh, an Englishman, irrefragably demonstrated the 

 electric nature of the torpedo in a series of experiments 

 given at La Rochelle, the old Huguenot town, in the 

 house of Marie Seignette, the discoverer of Seignette salt. 

 He showed simultaneously that the moment the shock 

 occurs the back and stomach of the torpedo are differently 

 situated in regard to the electricity. Walsh considers the 

 " falciform muscles " as mere electric machines that are 

 put in motion at the will of the animal. Soon afterward this 

 old term disappeared from science altogether, and the more 

 appropriate appellation of electric organs was bestowed 

 in its stead. A few years later, this same Walsh undertook 

 to make a series of experiments upon the gymnotus, sev- 

 eral living specimens having been brought to London at 

 his request. The conformity of the shocks was perfectly 

 demonstrated by an electric discharge ; indeed, Walsh even 

 succeeded in causing the gymnotus to emit distinct electric 

 sparks. Cotemporary with these experiments by Walsh, 

 the correctness of his theory was demonstrated in another 

 interesting manner. The eminent natural philosopher, 

 Cavendish, sunk under water a wooden board covered on 

 each side with tin foil, and succeeded in imitating the elec- 

 tric phenomena of the torpedo as demonstrated by Walsh, 

 by simply connecting the two sides of the board with a 

 Leyden battery. He thus showed the curved current of the 

 water, which completely agreed with that produced by the 

 electricity of the torpedo. Finally he demonstrated the 

 fact that a hand thrust into the water, although not com 

 ing in contact with the fish, must yet be affected by the 

 electric shock proceeding from it in proportion to the dis- 

 tance. 



Investigators received a fresh impulse through the dis- 

 covery of galvanic electricity and electro-magnetism. It 

 remained to be shown, however, that the electricity pro- 

 duced by the fish really possessed all the distinguishing 

 features of galvanic electricity. Alexander Bolta planned 

 numerous experiments, which, unfortunately, were never 

 put into execution. At the instigation of the celebrated 

 chemist, Sir Humphrey Davy, however, one of his brothers, 

 John Davy, performed extensive experiments in Malta 

 upon the torpedo. He observed the diversion of the mul- 

 tiplicator, the magnetizing of a steel rod, visible sparks, 

 decomposition of water and nitric acid, the reduction of 

 iodine from iodide of potassium, and, in short, the complete 

 register from a galvanic current to the production of physi 

 cal effects. He also maintained, in regard to the direction 

 of the galvanic current, as observed in the torpedo, that at 

 the time of the shock the creature's back is positively sit- 

 uated the same as the stomach. It is to the efforts made 

 by the first natural philosophers, Faraday, Schoenbein, 

 Colladon, E. du Bois-Reymond, and others, that science 

 owes the explanations given in regard to the two other 

 electric fish, the gymnotus and the silurus. It has been 

 ascertained that the current in the former flows from head to 

 tail, while in the latter it takes an exactly opposite direction. 



Anatomists were no less prompt by exploring the con- 

 struction of the electric organs than natural philosophers 

 were the physics. The most distinguished names in ana- 

 tomical science consecrated themselves, so to speak, to 

 this particular theme. An account of these investigations 

 can be read in the works of John Hunter, Etienne Geof- 

 froy, St. Hilaire, Pacini, and Max Schultze. The descrip- 

 tions of the torpedo and silurus written by Paolo Savi and 

 Th. Bilharv are masterpieces of anatomical research. Un- 

 fortunately, we are still without a like description of the 

 gymnotus. 



In order to obtain a thorough comprehension of the elec- 

 tric organs and their action, it is necessary to have re- 



