Jan. i8, 1872J 



NATURE 



227 



inside of these walls induces the opposite charge on the 

 outside, that the walls elongate under the compression 

 arising from the mutual attraction of these charges, and 

 shorten when this charge is discharged, because their 

 elasticity is then left free to come into play ? Nay, may 

 it not be that this action of the cell membrane is not ex- 

 cluded in those long voluntary muscles in which the fibres 

 seem to be made up of several cells or fibres over-wrapping 

 at their ends, rather than of a single sheathed fibre ? And, 

 certainly, this idea is not contradicted by facts remaining 

 in the background ; for, as will be seen in due time, these 

 go to shoiv that the walls of all cells and fibres are affected 

 electrically in the same way as that in which theshca'hof 

 the fibre of voluntary muscle is supposed to be affected. 

 So that, after all, the phenomena of rest and action in 

 sheathless muscular fibres may supply no valid objection 

 to the view which has been taken of these phenomena as 

 presented in muscular fibres with proper sheaths. 



And surely the evidence supplied by the new quadrant 

 electrometer is a sufficient contradiction to the objection 

 that the charge during muscular rest and the discharge 

 during muscular action are mere matters of imaginition, 

 for this evidence shows unequivocally that there is a 

 charge during this state of rest and a discharge .during 

 this state of action. It is not a question of inference 

 merely, such as it might be if the evidence supplied by 

 the galvanometer were alone available ; for here, as has 

 been pointed out, the current during rest, and the com- 

 parative disappearance of this current during action, may 

 in reality point to charge and discharge when traced to 

 their causes : it is a question of simple fact. Moreover, 

 the anatomical and physiological analogies existing be- 

 tween the muscular apparatus and the electrical apparatus 

 in the torpedo and the phenomena of secondary con- 

 traction, mike it more than probable that muscular 

 action is accompanied by a discharge analogous to that 

 of the torpedo. Like the nerves of the muscle, the nerves 

 of the electric organs originate in the same track of the 

 spinal cord, and terminate in the same manner. Like the 

 muscles, the electric organs are paralysed by dividing 

 their nerves. Like the muscles, the electric org ins, after 

 being thus paralysed, maybe made to act by pinching the 

 nerve beloiv the line of section. Like the muscles, the 

 electric organs are thrown into a state of involuntary 

 action by strychnia. Like the muscles, the electric 

 organs cannot go on acting without intervals of rest. 

 And lastly, the nerves of the electric organs, like the 

 nerves of the muscles, when somewhat exhausted, respond 

 in the same curiously alternating way to the action of the 

 " inverse " and " direct " current, if only discharge be taken 

 as the equivalent of contraction. In a word, these analo- 

 gies may be said almost to necessitate the conclusion to 

 which Matheucci was led in regarding them, namely this 

 — that musculir action is accompanied by a discharge of 

 electricity analogous to that of the torpedo. And cer- 

 tainly this conclusion is borne out rather than contradicted 

 by the phenomenon of secondary contraction which is 

 exhibited in a prepared frog's leg, when, after laying its 

 nerve upon the muscle of another such limb, contraction 

 is produced in the latter limb ; for here the only sufficient 

 explanation would seem to be that offered by Becquerel, 

 namely this — that contraction happens in the first limb 

 because its nerve is acted upon by an electrical discharge 

 developed in and around the muscles of the second limb 

 during action -a discharge which may not indirectly show 

 that there was a charge to be discharged during the pre- 

 vious state of rest. In a word, the evidence, direct and 

 indirect, must surely suffice to show that the idea of charge 

 during rest and discharge during action is something more 

 thin a mere matter of imagination. 



Nor can it be fairly urged that the force of the natural 

 electricity of the muscle is too feeble to produce the results 

 attributed to it. On the contrary, after what has been said 

 respecting the analogies between muscular action and the 



action of the electrical organs of the torpedo, it is quite 

 fair to suppose that the force of the discharge in muscular 

 action, instead of being feeble, miy be equivalent to that 

 of the torpedo ; and that the reason why it cannot be 

 detected in the same way may be that it is short-circuited, 

 and so mainly out of reach, within the body. 



3. How in nervous action electricity may do much of 

 what is commonly believed to be the work of a vital 

 principle. 



There is good reason to believe'* that the electrical law 

 of nerve-fibre differs in no wise from that of muscular fibre. 



There are also similarities between the principal struc- 

 tural elements of the nervous system from which it would 

 appear that what holds good of one part of this system 

 electrically may hold good of the other parts also. Nay 

 more, there is in these facts reason for believing that what 

 holds good of nerve-tissue generally may hold good of 

 muscle also, for the typal element of nerve and muscle is 

 evidendy one and the same. 



Looking at the different pirts of the nervous system — 

 ganglionic cells, and the peripheral nerve-organs — -and at 

 muscle cells and fibres, it is easy to trace the same struc- 

 tural plan. 



Central ganglionic cells, as seen in the ganglia of the 

 sympathetic system, and in other small ganglia of the 

 kind, consist of a round, oval, or pyriform miss of soft 

 translucent, granular substance, with which two or more 

 nerve-fibres communicate, and of an enclosing capsule 

 formed of a transparent membrane with attached or em- 

 bedded nuclei. The central granular substance, with 

 which the nerve-fibres communicate, and the investmg 

 capsule, are unmistakeable in the ganglionic cells of 

 the minute ganglia, but not so in the brain and spinal 

 cord. In the brain and spinal cord there is the same 

 central substance, but the proper cell wall is doubtful. 

 Moreover, the central substance, instead of being a 

 round, oval, or pyriform mass, with which the nerve- 

 fibres are connected at one point only, branches out 

 into several processes, which seem to be continuous 

 with the nerve-fibres. At the same time, these cells and 

 fibres are surrounded and supported by connective 

 tissue, called reticulum by Kolliker, and neurologia by 

 Yirchow — a tissue which, as Dr. Sharpey points out, 

 " is not merely an open mesh-work, but consists of fine 

 lamina: formed of a close investment of finest fibrils, 

 disposed as membranous partitions and tubular com- 

 partments for supporting and enclosing the nervous 

 bundles ; " so that, in the brain and spinal cord, as in 

 the smaller ganglia, there is good reason for believing 

 that the structure of the ganglionic cell is virtuilly the 

 same, namely, a central granular mass, with which 

 nerve-fibres are connected, and a membrane, with nuclei, 

 investing this mass. 



The peripheral nerve organs, of which th; principal 

 forms are three in number — the end-bulbs, the touch- 

 corpuscles, and the Pacinian bodies —agree in having (i) 

 an mward part or core of so t, translucent, finely granular 

 matter, in which one or more nerife-fibres end by bulbous, 

 or knobbed extremities ; and (2) an outer investing c ip- 

 sule of ordinary connective tissue, with nuclei. In the 

 end-bulbs and touch corpuscles this capsule is simple ; in 

 the Pacinian body it is made up of many concentric 

 layers, from forty to sixty in number, with nuclei, these 

 layers, "encasing each other, like the coats of an onion, 

 with a small quantity of peliucid fluid included between 

 them," being strung together where the nerve passes 

 through. The structural plan is still that of the ganglionic 

 cell — a central mass of granular matter, with which nerve 

 fibres are intimately connected, and an investing capsule, 

 simple or complex, as the case maybe; and this world 

 seem to be the plan of all the peripheral parts of the 

 nervous system without exception, for it is a question 



• See N.\TURE, Jan. 4, 1872. 



