SCIENCE. 



opposition to physiological, chemical and anatomical 

 facts, which recognize a vast difference between these two 

 organs. 



The preference certainly is due to that mode of investi- 

 gation which casts away all artificial proofs of closer re- 

 lationship between the muscles and the electric organs 

 and regards them as independent and well-authorized 

 members. Indeed, the reasons given by those who ac- 

 cept an especial connection between the two are formed 

 merely upon the identity of this relationship with the ner- 

 vous system, and not upon any similarity to the actual 

 qualities peculiar to these organs. Such grounds, how- 

 ever, can have no importance as regards this question and 

 can bring the electric organs no nearer to the muscles than 

 to the organs of sight or any other organ. 



But are the electric organs really so independent and 

 isolated in the animal organization ? And to what freak 

 of nature are we indebted for the remarkable fact that 

 out of all the fish that exist, only three are distinguished 

 by such powerful weapons ? The theory of evolution 

 which now rules organic natural sciences, always has a 

 well-tried domestic remedy on hand for such questions. 

 This theory discovers in formations like the electric or- 

 gans which stand out as prominent exceptions to the con- 

 formity of animal construction, the distinct remains of a 

 powerfully developed species belonging to an early epoch 

 of geology, or, in other words, the solitary descendants of 

 a once mighty family. According to this, the appearance 

 of the electric organs in the three fish may seem much 

 less mysterious, and the great anatomical diversities 

 which exhibit themselves throughout these organs are, 

 perhaps, best explained by the idea that in these fish we 

 have before us the final issue of a powerful species, the 

 last remains of an extinct family. That such a family 

 did exist is proved by the discovery of a petrified torpedo 

 in the tertiary strata of Monte Bolca in Verona. 



But also in the cotemporary creation the electric organs 

 are not so badly devoloped as a superficial observer 

 might suppose. In the non-electric torpedo of the Kaja 

 species, and also those which are found in the African 

 rivers, peculiarly constructed organs have been discovered 

 from which an electric effect cannot be produced, but 

 which, nevertheless, are composed of strata similar to the 

 real electric organs. These may, perhaps, be correctly 

 termed electric organs, which are either newly constructed 

 or else in a state of incomplete development. 



The materials so far collected by anatomists and phy- 

 siologists concerning this question do not admit of a 

 marked decision. The organs present many things in 

 commrn with the electric sirata it is true, but beyond 

 this turther investigation seems useless. 



In one other respect physiology is likewise unable to 

 give a definite explanation. E. du Bois-Reymond was 

 the first to ask how it happened that the electric fish was 

 not the victim of its own power, and how it was possible 

 that the forcible electric discharges which killed other 

 fish completely escaped the electric fish itself. 



Now we all know that the nerves and muscles of the 

 electric fish are excited by means of an electric current, 

 and a much stronger one is perhaps required here than 

 would be the case with other animals, yet the electric 

 discharges, although of such force, produce no effect 

 whatever upon the fish. There are influences at work 

 here, which so far we are unable to understand. We 

 naturally suppose, however, that the great dimensions of 

 the nerve fibres and ganglion cells, together with a vig- 

 orous nervous system, have a great deal to do with it. 



In conclusion, it still remains for us to put the great- 

 est question of all concerning the electric fish, namely : 

 what is the origin of that powerful force which at the 

 creature's will so suddenly appears and departs with 

 equal rapidity, and also what is the precise mechanism 

 of the electric organs ? 



It has been shown that as science advanced, the elec- 

 tric fish became better known and more carefully studied. 



31 



The ancients were only aware that such a thirg' existed ; 

 a conviction, however, that they were incapable of 

 analysing further. Redi taught us to consider the elec- 

 tric organs as the apparatus which produced the effect. 

 E. du Bois-Reymond put. the electric strata in place of 

 the electric organs, by proving that the mechanism of 

 the latter was reduced to the combined action of count- 

 less analogous electro-motory monads, which was ex- 

 plained by the supposition that when the electric dis- 

 charge occuned one part of the strata was positive and 

 the other negative. By this means our question con- 

 cerning the mechanism of the electric organs is partially 

 answered. It now remains to ask what takes place 

 when the electric discharge occurs? 



Now, in order to imitate the effects produced by the 

 malopternus, it requires the strongest electro-motor ap- 

 paratus ihat can be found. The natural philosopher 

 must use the most powerful batteries contained in his 

 labratory, if he wishes to approach the force which 

 causes 2% pounds of water, salt and albumen to come 

 under its influence. 



The muscles are no less powerful. The dorsal mus- 

 cle of a frog consists of a few grammes of water, salt 

 and albun en, and yet it is capable of lifting a kilometre. 

 In both cases an extraordinary development is apparent, 

 mechanical in one and electric in the other. 



Hitherto, no one has succeeded in correctly establish- 

 ing the facts relating to this mechanism. Nevertheless, 

 concerning the electtic eel there is an accepted theory, 

 which explains all the phenomena in a most satisfactory 

 manner. 



This theory originated with Colladon and E. du Bois- 

 Reymond, and states that in the electric substance, dis- 

 polary eltciro-moter molecules are to be found. 



In a state of repose they turn towards their pole in 

 every direction, or else in two ways opposed to each 

 other, so that the electricity arises on all sides and dis- 

 appears without. When the shock takes place, the pos- 

 sitive pole is turned quickly towards the electric organ 

 whence the positive current proceeds. 



OBSERVATIONS ON ICE AND ICEBERGS IN THE 

 POLAR REGIONS* 

 By Lieutenant F. Schwatka, U. S. N. 



The formation of icebergs, from the terminal fronts o f 

 glaciers, has long been a disputed point among savants, 

 some contending that they derive their origin from the 

 corroding action of the water,undermining their projecting 

 f ices until the weight of the superincumbent mass, act- 

 ing as a lever, overcame the cohesive power of the glacier 

 along some line of least resistance, when the berg fell in- 

 to the sea, and was wafted away by the tide-winds and 

 currents. Others can only account for such huge moun- 

 tains of ice by supposing that the glacier, slowly crawling 

 into the sea, and plunging beneath a denser flu ; d, has a 

 bouyant effort or tendency to rise, which, at last, becomes 

 so great that it overcomes the line of least resistance, 

 near the shore, and the berg rises into the sea, to be at 

 the further mercy of its uncertain elements. Both theor- 

 ies have proved to be correct. The former generally oc- 

 curs where currents, heated in more temperate climes, pour 

 their tepid waters northward, and expend their thermal 

 forces in contending with the vast packs, floes, and 

 glacieis ot ice, that obstruct their polar march, and whose 

 fast corroding action has the slow glacier only a com- 

 paratively short time in its embraces before it has 

 undermined it. The latter results where the chilled 

 waters from the Pole have but little effect upon the 

 glacial front ; and slow as it is, it has time to crawl into 

 the sea to give forth its mighty masses. Sometimes both 



* Read before the Nationsl Academy of Sciences, New Ycrk, 18E0. 



