!90 



A^A TURE 



[July 26, 1900 



on p. 51 that the writing of the scribes was sometimes 

 so minute that magnifying glasses were used for reading 

 by the Assyrians, and that short sight " must have been 

 common in the Babylonian schools," is, to say the least, 

 rather fanciful, the only evidence for the statement being 

 a circular crystal object found by Layard at Nineveh, and 

 thought to be a lens, but the use of which is unknown. 

 That there was ever "a monotheistic school" at Erech 

 (p. 262) would, we think, be difificult to prove, and the 

 evidence for " human sacrifice " referred to on p. 103 

 should surely have been given. It is, no doubt, a con- 

 sequence of the omission of references that we sometimes 

 come across repetitions in the book, as, for instance, the 

 quotation referring to the Chaldeans and their ships in 

 connection with Eridu on pp. 9 and 183 ; the suggested 

 identification of Sar-ilu with Israel on pp. 17 and 191, 

 the description of the letter referring to a ferry-boat on 

 pp. 186 and 215, &c. Misprints, too, are not uncommon, 

 as, for example, "the eighteen-hundredthj part " (p. 114), 

 "I will lie up five shekels of silver" (p. 225), " Emu- 

 talum " for " Emutbalum /' (p. 2 1 1 ), " weight " for " night " 

 (p. 266), " bears " apparently for " beasts " (p. 52), " cunei- 

 plain " apparently for "plain" (p. 211), and on p. 157 we 

 are told that " Aramaic became the lingua panca ... in 

 the commercial world." Prof. Sayce is probably not to 

 blame for such misprints, for the American editor was 

 doubtless responsible for the correction of the proof- 

 sheets. 



ELECTRICAL ORGANS. MUSCLE OR NERVE? 

 Beitrage zur Physiologie des elektrischen Organes der 



Zitterrochen {Torpedo). By Siegfried Garten. Pp. 116, 



4 plates. (Leipzig : Teubner, 1899.) 



ALTHOUGH electrical fishes have been the object 

 of scientific curiosity and investigation for nearly 

 300 years, it is only in the last half of this century 

 that physiologists have realised the great importance, for 

 general physiological problems, of the phenomena pre- 

 sented by these remarkable animals. The discovery and 

 investigation of the electrical phenomena accompanying 

 excitation or activity of all the excitable tissues in the 

 animal body have rendered it of supreme importance to 

 attack the problem and the causation of these electrical 

 changes in the organ, where the " electrical function," so 

 to speak, attains its highest degree of development. It 

 seems probable that electrical organs may be developed 

 by the transformation of many different kinds of tissue. 

 In the greater number of these fishes, however, in- 

 cluding that which is the subject of the memoir under 

 consideration (Torpedo), the organ is formed by a trans- 

 formation of embryonic muscle- fibres, accompanied by a 

 disappearance of the cross-striated contractile material, 

 with a great hypertrophy of the nerve-endings. The 

 electrical discharge of the organ, with an E.M.F. prob- 

 ably amounting to 100 to 200 volts (Gotch) and 

 lasting about 6/1000 of a second, may be excited 

 reflexly or by excitation of the nerve to the organ, 

 or, using strong shocks, by stimulation of the organ 

 itself. The direction of the current in the fish is from 

 ventral to dorsal surface. The electrical organ in 

 NO. 1604, VOL. 62] 



the torpedo consists of an array of columns, each 

 column being composed of about 400 transverse discs 

 representing the electromotive elements of the organ. 

 On the ventral surface of each of these discs we find 

 the complicated terminal arborisation or network of a 

 nerve-fibre, embedded in granular protoplasm, and 

 separated from the disc by the remains of the primitive 

 muscle-fibre from which the organ was developed. 



We must assume that it is in consequence of these 

 structural arrangements that the excitatory electrical 

 change in the whole organ, instead of passing from one 

 end to the other as a wave, and so giving rise to a 

 diphasic variation of small extent, causes merely a 

 change in one direction, which is summated in propor- 

 tion to the number of discs in the pile, so producing a 

 monophasic variation of considerable E.M.F. It is 

 evident that we could conceive of each disc as consisting 

 of an inferior part, which is excitable and therefore 

 capable of the chemical changes associated with excita- 

 tion, and of a superior part, structurally and chemically 

 continuous with the inferior, but incapable of excitation. 

 The question at once arises whether these two parts are 

 represented by nerve and muscle, or whether the chief 

 excitatory change takes place in some of the structures 

 derived from the embryonic muscle-fibre. Is the 

 electrical change an action current of nerve-ending or of 

 muscle ? 



Du Bois Reymond, for theoretical reasons, supported 

 the latter view, and at the same time laid great stress on 

 a remarkable property of the organ. He found that 

 the electrical conductivity of the organ was greater for 

 homodromous currents, i.e. those in the direction of the 

 discharge of the organ, than for heterodromous. It was 

 shown later by Gotch that this irreciprocal conductivity 

 is only apparent, Du Bois Reymond's results being due 

 to the fact that, in measuring the current passing through 

 the organ, he was measuring the algebraic sum of the 

 battery current and the current excited in the organ 

 itself. Naturally, therefore, the homodromous current 

 was greater than the heterodromous. 



Gotch has, also drawn attention to the fact that in the 

 electrical organ we have an opportunity of deciding the 

 nature of the demarcation-current consequent on injury. 

 Since in this organ the demarcation-current is always in 

 the same direction as the excitatory-current, whatever 

 may be the position of the injury, he concludes that the 

 demarcation-current or current of rest is really in all cases 

 an action-current due to the continued stimulation at the 

 seat of injury. 



On these three questions, but especially with regard to 

 the nervous or muscular nature of the excitable tissue, 

 additional evidence is furnished by Garten, whose re- 

 search is devoted chiefly to the elucidation of three points 

 — the effect of nerve-section and subsequent degenera- 

 tion on the direct excitability of the electrical organ ; 

 the effect of drugs, such as curare, which are direct 

 poisons for nerve-endings ; and the action of veratrin as a 

 specific muscular poison. 



The results of these experiments are a strong confirma- 

 tion of the views put forward by Gotch. During the 

 first eight days after section of the nerves, the organs can 

 be excited either directly or indirectly ; from the eighth 



