226 



NATURE 



{Jan. i8, 1872 



ELECTROPHYSIOLOGICA : 



SHOWING HOW ELECTRICITY MAY DO MUCH OF WHAT IS 

 COMMONLY BELIEVED TO BE THE SPECIAL WORK OF A 

 VITAL PRINCIPLE 



III. 



2. /;/ conttiuiation of Ihe question — How in mtisculoy 

 action electricity mav do much of what is commonly be- 

 lieved to be the H'ork of a 7'ital principle. 



CONNECTED with the history of electrotonus as 

 exhibited in these experiments* are also ot^^er 

 facts which must not be overlooked in this attempt 

 to trace out the workings of electricity in muscular 

 action — facts which show that the departure of con- 

 tractility and the arrival of rigor mortis are con- 

 siderably retarded by both forms of electrotonus. Left 

 to itself, the gastrocnemius of the frog loses its con- 

 tractility and passes into the state of rigor mortis in a 

 time varying with the season and from other causes 

 from 6 to 12 hours ; but not so when left to the action of 

 electrotonus. In this latter case, indeed, the con- 

 tractility may remain for 18, 24, or 36 hours — for a 

 longertime inanelectrotonus than incathelectrotonus — and 

 even then there may still be no signs of rigor mortis. 

 Once, where anelectrotonus was kept up steadily all the 

 time, and where contractility lingered for 36 hours, the 

 muscles were still limber at the end of 48 hours. No 

 doubt, before exact conclusions can be drawn in these 

 matters more experiments are wanted, many more ; but 

 it is not necessary to wait for these in order to be certain 

 that the departure of contractility, and the arrival of 

 rigor mortis, are considerably retarded by the action of 

 both forms of electrotonus. And it is simply to the bare 

 fact that attention is now directed. 



What then 'i Do these facts bear upon what has gone 

 before, and, if so, how t 



The facts are obvious. In anelectrotonus and cathe- 

 lectrotonus alike there are— suspension of the tetanus 

 caused by feeble faradaic currents, elongation of muscle, 

 exalted contractility, together with considerable retarda- 

 tion in the time at which contractility passes off and 

 rigor mortis comes on. In anelectrotonus and cathelec- 

 trotonus the parts, muscle and neive alike, are charged 

 with a charge larger in amount than that which is 

 natural to them — a positive charge in anelectrotonus, a 

 negative in cathelectrotonus. The facts, indeed, are 

 strangely in keeping with the premises. Only let it be 

 su])posed that the artificial charge acts upon the dielectric 

 sheaths of the fibres as the natural charge has been sup- 

 posed to act, but in the contrary direction, that is from 

 without to within instead of from within to without, the 

 charge imparted to the outside inducing the opposite 

 charge on the inside, and all the rest follows. The 

 artificial charge is larger in amount than the mutual 

 charge, and hence the increased elongation of the 

 muscular fibres, the compression arising from the natural 

 attraction of the two opposite elements of the charge 

 keeping up a state of elongation proportionate to the 

 amount of the charge. Hence, also, the suspension of 

 the tetanus by electrotonus, for if the charge elongates the 

 fibres it is easy to see that another of its actions may be that 

 of suspending or antagonising muscular action. And hence 

 again the increased contractUity, for, according to the pre- 

 mises, contraction, happening under these circumstances, 

 will be greater because the elasticity of the muscle has 

 freer play at the discharge. In these matters the artificial 

 charge plays the same part as the natural charge, only 

 more energetically, nothing more. And not less so, as it 

 would seem, in the action exercised upon the pass- 

 ing off of contractility and coming on of rigor mortis. 

 Contractility passes off and rigor mortis comes on in the 

 ordinary course of things, because the muscle loses its 

 natural electricity. Contractility passes off and rigor mortis 

 Sm Nature, Jan. n, 1872. 



comes on more slowly in electrotonus because the artificial 

 charge associated with this state can take the place and 

 do the work of the natural charge. This is all. Indeed, 

 so far, the whole electrical history of muscle would seem 

 to point to the view which led to the experiment with the 

 elastic band, and to show that living muscle is kept in a 

 state of elongation by the presence of an electrical charge, 

 and that contraction is nothing more than the action of 

 the fibres, by virtue of their elasticity, when liberated by 

 discharge from the charge which kept them elongated 

 previously — ordinary muscular contraction differing from 

 rigor mortis in this only, that the charge which prevents 

 contraction is suddenly withdrawn, and immediately re- 

 placed, in the former case, and gradually withdrawn, and 

 not replaced, in the latter case. 



Upon this view, also, it is possible to get a glimpse of 

 the reason why contraction is more antagonised by an- 

 electrotonus than by cathelectrotonus ; and why contrac- 

 tility is slower in passing off, and rigor mortis slower in 

 coming on, under the former state than under the latter. 

 In anelectrotonus the artificial charge of the parts, muscle 

 and nerve alike, is positive, and, being so, the sheaths 

 are positive externally, and (by induction) negative inter- 

 nally, the manner of charging, which, there is reason to 

 believe, is natural to the muscle. In cathelectrotonus, on 

 the other hand, the opposite state of things obtains. Here 

 the artificial change is negative, not positive. Here, con- 

 sequently, the charging of the sheaths is negative on the 

 outside and positive on the inside — a state of things which 

 is not natural to the fibres, or which is only met with 

 exceptionally, when these fibres are upon the point of 

 passing into the state of rigor mortis. In anelctrotonus, 

 therefore, the natural charge may co-operate with the 

 artificial charge in a way in which it cannot do in cath- 

 electrotonus ; and which, without further comment, it is 

 easy to see may explain in some degree why contraction 

 is more antagonised by anelectrotonus than by cathelec- 

 trotonus ; and why contractility passes ofi"and rigor mortis 

 comes on more slowly under the former condition ttian 

 under the latter. 



As I have shown elsewhere,* the whole electrical history 

 of muscle is in keeping with this view. The charges ob- 

 tained from the common friction machine act in the same 

 way as those associated with electrotonus. Everywhere, the 

 question is not of polarisation and of changes in direction 

 of a continuous curi'ent, but simply of charge and dis- 

 charge. Everywhere it is charge preventing, and dis- 

 charge permitting, action. In a word, the whole electrical 

 history of muscle would seem to show that electricity may 

 have much to do in what is commonly believed to be the 

 work of contractility and tonicity, and that the way in 

 which this work is done is that which is here pointed out. 



Against this view, however, sundry objections may be 

 urged. It maybe said that the phenomena of muscular 

 action in muscles with sheathed fibres cannot be ex- 

 plained after this fashion. It may be said that the proof 

 of charge during rest and discharge during action is little 

 more than a matter of imagination. It may be said that 

 the force of the natural electricity of muscle is inadequate 

 as force. But, in reality, these objections, when fairly 

 looked into, prove to be of little value. 



No doubt the fibres of involuntary muscles difl'er from 

 those of voluntary muscles in ha\ ing no proper sheaths. 

 Instead of having those sheaths, indeed, they are made 

 up of cells, mostly fusiform in shape, imbedded in a sort 

 of homogeneous plasm or matrix ; and these cells, there is 

 reason to believe, are the contractile elements of the fibres. 

 Still it is not easy to allow the force of any objection aris- 

 ing in this fact, for may it not be that the walls of these con- 

 tractile cells, which, like the sheaths of the fibres of voluntary 

 muscle, in the main consist of the material of elastic tissue, 

 behave in the way the sheath is supposed to behave under 

 the charge and discharge, that a charge developed on the 



* "Dynamics of Nerve and Muscle." Macmillan. 



