Therapeutic electricity and practical muscle testing

Front matter

T

AND

PRACTICAL MUSCLE TESTING

Chapter I. — Electromotive Force (E. M. F.) . ,, II. — Ohm's Law

„ III.— How to Measure and Vary E. M. F. „ IV.— Various Kinds of E. M. F. ,, V. — Magnetism. The Induction Coil „ VI.—" Static " Electricity .

,, VII. — Currents of Great Frequency and High Potential „ VIII. — Current from the Main

Part II 27 31 3(3

47 64 70

Chapter I. — The Electrotherapeutic Outfit . . .83

II. — The Human Body a Source and a Conductor of

Electricity. . . . .92

,, III. — Electro-diagnosis . 108

„ IV.— The Motor Points . . . .133

,, V. — The Action of Muscles and the Consequences of

their Paralysis . . 143

Part III

Chapter I. — General Electrisation — General Faradisation — Central Galvanisation — Subaural Galvanisation — Galvano-faradisation — Local Treatment of Muscles — Local Treatment of the Spinal Cord — Faradic Brushing and other Forms of Cutaneous Excitation ..... 165 II. — The Electrotherapeutics of Muscular Atrophies . 172 ,, III. — The Electrotherapeutics of some Symptomatic Diseases of the Nervous System. — The Electrotherapeutics of Neuralgias, and of Neuroses . 189

VI CONTENTS

PAGE

Chapter IV. — The Electrotherapeutics of Rheumatism : of Gout: of Diseases chiefly characterised by Vaso-rnotor and Trophic Disturbances : of Diseases due to Failure or Perversion of Nutrition . 205

„ V. — Diseases of the Alimentary Canal. Incontinence of Urine. Ascites. Rickets. Suspended Animation. Electricity a Test for Death . 211 VI— Diseases of Organs of Special Sense. Aneurism 218 ,, VII. — Diseases of Women . . . 223 „ VIII. — Cutaneous Diseases . . . 229 „ IX. — Strictures. The Cystoscope. The Urethroscope.

The Laryngoscope The Vaginal Speculum . 23-t

„ X. — Cataphoresis .... 238

XI.— The Hydro-electric Bath . . 252

Appendix

Testing foe Faults in a Circuit . 265

LIST OF ILLUSTRATIONS

Fig. page

1. Diagram to illustrate strain in the aether . . .6

2. Diagram to show analogy between a flow of water driven onwards by

a pump and an electric current produced by the E. M. F. of a battery . . . . . . .9

3. A "Voltaic cell" . . . . . .10

4. A Leclanche cell ..... 12

5. A Dauiell cell . . . . . .13

6. A Grenet cell . . . . . .14

7. Hellesen dry cell . . . . . .15

8. The " Lithanode " accumulator . . 17

9. Diagram to show ratio of current to resistance . . 18

11. Milliamperemeter . . . . . .22

12. Illustrates the electrical units by means of the water analogy . 23

13. Cells connected " in series " . . . . .27

14. Cells connected " in parallel " . . . .28

15. Cells connected "in groups" . ... 29

16. A "continuous" E. M. F. ... .31

18. An alternating E. M. F. (symmetrical and sinusoidal) . . 32

19. Primary induced E, M. F. (dis-syuimetrical) . . .33

20. Galvano-faradic E. M. F. . . . .33

21. E. M. F. of constant current dynamos . . . .34

22. Static E. M. F. (" instantaneous ") . . .34

23. Undulating E. M. F. obtained by particular methods of discharging a

condenser . . . . . .35

24. Magnet and its lines of magnetic flux ... 36

25. Circular lines of magnetic flux surrounding a wire through which a

current is passing . . . . .37

26. The movement of electricity produces magnetism, and the movement

of a magnet produces an electric current . . .37

27. Mutual induction . . . 38

Vlll LIST OF ILLUSTRATIONS

Fio. PAGB

28. Electro-magnetic induction

29. Magneto-electric induction ....

30. A medical induction coil ....

31. Diagram of primary and secondary windings of medical induction

coil . ■

32. Automatic vibrator or " Wagner hammer "

33. Pith ball electroscope showing electrostatic attraction and repulsion

34. Electrostntic induction ....

35. Gold leaf electroscope ....

36. The "electrostatic field " ....

37. The charged electrophorus ....

38. The electrophorus, a ground connection having been made .

39. The electrophorus, the cover having been raised and the electrostatic

circuit lengthened ....

40. Diagram of influence machine with condensers

41. Equipment for " static " treatment

42. " Static induced " currents

43. " The Universal Discharger." — Method of localising souffle, sparks

and other forms of discharge

44. High frequency currents — "condensation" 44a. High frequency currents with Wehnelt interrupter

45. Diagram showing high frequency currents obtained from alternating

light currents .....

46. " Autoconduction " .....

47. Simple form of dynamo ....

48. The commutator ...

49. The "sliding shunt " ....

50. Interlocked shunt rheostat ....

51. Rheostat for using dynamo current for " galvanisation and faradisa

52. Rheostat for using continuous dynamo current for cautery purposes

53. Gaiffe's " Universal Transformer " .

54. Transformer for alternating dynamo currents for cautery and surgical

lamps .....

55. d'Arsouval's dynamo for " sinusoidal voltaisation "

56. A " combined " battery ....

57. A cautery and light battery ....

58. Cautery burners .....

59. Universal handle for cautery ....

60. Rheostat with mercury contact

61. Bergonie's rheostat .....

62. Lines of current flow and lines of equal potential

63. Current diffusion .....

64. Arrangement of molecules before electrolysis

65. Showing electrolysis .....

66. Showing electrolysis and cataphoresis

67. The "normal polar formula" ....

39 39 41

42 43 47 48 49 52 53 53

54 58 59

61 65 66

67 67 70 71 73 74

75 76

LIST OF ILLUSTRATIONS

IX

Fig.

69. 70.

72. 73.

74. 75. 76. 77. 78.

79. 80. 81. 82. 83. 84.

Showing current " density " and " virtual " anode and kathode

Showing " reversal of the formula" (in R.D.)

(1) Myographic tracing of A.C.C. ahd. ruin, dig. (2) Myographic

tracing of A.C.C. abd. min. dig. (muscle fatigued). No reaction to

K.C. (Case of R.D. from pressure of a splint) . (1) Myographic tracing of K.C.C. in corresponding muscle of the

sound hand. (2) Myographic tracing of A.C.C. in corresponding

muscle of the sound hand .

Clinical myograph of Radiguet .

Curve expressing the normal law of contraction Distribution of sensory nerves roughly shown

Plates I, II, III.— The Motor Points.

Photograph showing action of muscles

Diagram to explain the constitution of the neurons and the course of

secondary degeneration Rough diagram of anatomy and pathology of spinal cord

Distribution of reflex and other functions of the cord

The telephone probe

Cataphoretic electrode (Meissner)

Automatic current reverser for cataphoresis (Meissner)

Cataphoretic electrode

„ vaginal electrode

Dental cataphoretic electrodes

Diagram showing electrical conditions in a bath when an earth connection is made ...■■• Schema for high frequency currents with electrolytic interrupter

PAGE

103 115

123 124

128 128 129 130 130

144 146 148 149 151

264 270

Introduction

This manual deals with electricity solely from its medical The scope and aspect. But the practitioner of medicine must in the first electricity in instance travel over ground that is not exclusively his own. medic,ue - In therapeutic electricity, as in other branches of applied electrical science, electricity qwes its usefulness to the fact that it offers a ready and rapid means of transferring energy from one point to another.* The electrical engineer by various devices transforms chemical, mechanical, or other energy into electrical forces, and so makes the former reappear, when and where he will, as light, or heat, or sound, or motion. The medical man similarly transforms the same energy and transfers it ; but this time it is destined to reappear as work, in the shape of physiological action, physical effects, or electrolytic change, on the various tissues and organs of the body. It may be true that for the latter purposes no very profound acquaintance with electrical phenomena is absolutely required ; still it is quite certain that the better the physician is acquainted with the fundamental principles of electro-physics the better he will be able to turn them to account.

There was a time, and it is not long ago, when electricity

* S. Thompson.

2 THEUAPEUTTC ELECTRICITY

was regarded only as a muscle-contracting stimulus, it was measured "by cells" instead of by definite electrical units, its sedative effects were overlooked, its cataphoretic power was ridiculed, its influence on nutrition was unknown. With an increasing knowledge of electrical phenomena and a wider conception of biological physics, views and methods are both undergoing change. Physiologists now begin to recognise that chemical and electrical processes are inseparable from those hitherto called "vital," and that electromotive force is very commonly the outcome of physiological action. Based on such conceptions, therapeutic electricity now stands upon a higher level and advances along broader lines ; and nothing is more evident than that the only one competent to use it is the duly instructed medical man. An improved instrumentation is at hand to help him. The use of the galvanometer, the rheostat, the current selector, the voltmeter, and the commutator are now the commonplaces of electro-therapeutic work. The modern induction coil, the "combined battery," and the current controller* are an astonishing advance on the battery of Daniell elements which, fifty years ago, Remak was obliged "to take to pieces and clean daily." Every form of electrical energy is now utilised in medicine. The three conventional currents, the " Galvanic," the " Faradaic," and the " Static " are now supplemented, and to some extent supplanted, by electricity in new modalities. In the electric lighting currents that pass his door, the medical man finds unfailing sources of electrical supply, of unlimited usefulness, and novel power. From the lead of an ordinary incandescent lanrp he helps himself to an ever-ready supply of electrical energy, either of a continuous or of an alternating kind. The former furnishes a current which, used through a proper controller t will do for him all that the uniform flow of the galvanic cell can accomplish. Passing the same current through a coil he obtains

* For utilizing public supply currents. t See p. 73.

INTRODUCTION 3

that dis-symmetrical alternating current universally familiar as the current of the medical induction apparatus. Still availing- himself of the same supply he heats his cautery, lights an exploring lamp, or charges his accumulators ; or, passing the current through a motor, he drives his static machine or actuates his therapeutic alternator. The latter can in its turn be arranged to supply a current having all the smoothness and other cpialities of that known as " sinusoidal," and with its rapidity, its electromotive force, and even the shape of its electromotive force curve, under absolute control. If the current that is supplied in the street mains be an alternating one, it is passed through a transformer to apply it to the body, to electrise the water-bath, to light the exploring lamp, and to heat the cautery.

The most recent addition to our resources are those currents of great frecjuency and high potential, under whose influence the respiratory combustions have been shown to increase, skin action to become more active, arterial tension to fall, certain bacilli to die, certain toxines to lose their toxicity. These currents, first experimented with by d'Arsonval, have proved useful in the treatment of rheumatism, gout, asthma, and diabetes.

Thus the scope of therapeutic electricity is widened. Its usefulness is no longer limited to diseases of the nervous system ; its procedures no longer confined to localised methods. " L'electrisation localisee," the watchword of Duchenne, now covers only half the ground. The great feature of modern practice is that the latter no longer limits itself to strictly local applications, but that it also resorts to such methods of general electrisation as have a demonstrable influence on the nutritive processes and on cell life ; and what the physician aims at by treatment of this kind is so to modify the perverted vital activity of cells and tissues as to strengthen their resistance to morbific agencies, and arouse their inherent recuperative power. This is all that treatment can accomplish. " Cure " is the work of the living- cell.

O

Electricity and electrification. — "What is electricity? Tw hundred and fifty years ago it was a viscous fluid ; to-day we are awaiting proof of some universal connecting medium, some " subtle tenuous aether," that will explain electricity, magnetism, and light, perhaps chemical affinity and gravitation. It is only open to us to say that electricity is an invisible agent, unknown excepting by its effects. It is apparently indestructible and uniformly distributed. The textbooks of half a century ago follow Franklin in his " one fluid " theory and Symner in his " two fluid " theory. According to the former, electricity is a single imponderable fluid, the particles of which, although they mutually repel each other, attract all matter ; and every substance has the capacity for containing a definite quantity of this fluid. When the normal quantity is present no phenomena are manifested ; when there is less than the full quantity the body is charged negatively ; with more than the quantity the body is charged positively. In other words, the phenomena of electrification depend upon a plus or minus of the fluid. The " two fluid " theory assumes that there are two kinds of electricity, and these are compared to fluids. They are self-repellent, but mutually attract. They both attract matter. In an unelectrified body they coexist in equal quantities and neutralise each other. The act of separating these fluids constitutes the phenomena of electrification. These fluids are distinguished as positive and negative, and by the signs plus and minus.

Whatever it may be, electricity is certainly not a materia] fluid : it has no weight, and it is impossible to imagine a substance which is self -repellent.

The fluid theory gave place to the view that electricity is "a form of energy." Now energy, like matter, is indestructible, and so apparently is electricity; but it is not true to say of any particular form of energy that it is indestructible. It is obvious that any form of energy as such can be created by being transformed from some other form or destroyed by

INTRODUCTION 5

being transformed to some other form ; for example, heat is generated at the expense of motion destroyed. The point, therefore, arrived at is this. Electricity is not a form of energy, and little can be stated positively of its true nature. But electrical phenomena, i. e. electrostatic action, electro-magnetic action, electrical waves — what, in short, is called electrification — is a form of energy, and can be made to appear and disappear ; and a great deal is known of it and of the laws under which it operates.*

According to present views electricity is regarded as closely connected with the aether. Perhaps it is the aether— that (still hypothetical) aether that fills all space, and pervades all bodies, and acts as the medium by which the movements of all bodies are carried on, — " the transmitter of all motion and energy." Now taking for granted the existence of an aether, it is assumed, according to one view, that the atoms of all substances are kept together by lines of electrostatic force, lines existing in the aether ; that, amongst other things, what is known as chemical affinity is nothing else than this electrostatic attraction (Fitzgerald). This leads to the conception that all electrification is produced by separating the atoms of bodies. Such an operation clearly involves two factors : (1) the effort to electrify, i. e. the overcoming the power of the atoms of bodies to cling together, and (2) resistance to being electrified, this resistance consisting of the persistence of the particles to cling together. If by means of friction or chemical action the atoms are separated or drawn asunder, these connecting lines of electrostatic force attached to the atoms are drawn out or stretched like elastic bands, and space {i. e. the intervening aether) thus becomes filled with lines of electrostatic force uniting the positively and negatively electrified bodies, each connecting line having a unit of positive electricity at one end and a unit of negative electricity at the other (Fig. 1). These connecting lines, as already stated, are attached to atoms, therefore, although such lines

* Wright.

THERAPEUTIC ELECTUIC1TY exist in aether, they always begin and end on matter. These elastic lines of force represent hypothetical lines in the aether

along which "stress" exists, i.e. the aether is strained; in

A

B

Fig. 1. — Diagram to illustrate strain in the aatlfer.

other words, there is an elastic yielding in it from which it always has a tendency to recover.

There are now signs that this theory of the tether has in its turn had its day, and is giving place to a " rotationally elastic fluid aether" (Larmoor). According to Prof. Hicks and others, " there are difficulties especially connected with reflection and refraction which decide against any theory which imposes on the medium the quality of solidity. On the other hand, a rotational theory seems to meet such difficulties. This theory attempts to show that the aether may possess such elasticity as will enable it to transmit undulations of transverse type " (waves of light and electricity), while " at the same time it allows masses of matter to move freely in it as if it were a gas." The rotation of a fluid in vortices seems to be the only way in which it can be imagined that the aether " may acquire the necessary quasirigidity without actually becoming a solid." The theory of electricity, therefore, is so far the theory of the aether.

INTRODUCTION 7

Such views are touched upon here to bring home to the mind the fact that the electrician does not deal with a material substance but rather with a condition ; that in the therapeutic application of electricity no material substance passes through the body ; that the electrification of matter does not involve " the addition, removal, or transfer " of any material thing.

Having said this much, it is not proposed again to venture upon the changing quicksands of electrical theory, but to revert at once to the well-beaten track ; in other words, to fall back upon that conventional phraseology which is founded upon an imperfect analogy between an electric current and a fluid flow. Therefore, having satisfied ourselves that electricity is not a fluid, that electrical energy travels not by the conductor but by the asther, that electrification is not a substance but a condition, we at once proceed to sjjeak of " the electric current," of " the electrostatic flux," of the " electro-magnetic flux," of " the conductor which forms a path for the current," of " the pressure which forces electricity through a circuit; " and we now use this language with an easy mind, for we do it with the proviso that such phrases are not intended to be an expression of actual facts, but only a means of " elucidating phenomena."

PAET I

CHAPTER I

Electromotive Force (E. M. F.)

{"Pressure;" "Potential;" "Difference of Potential ;" " Voltage ")

Suppose two vessels (a and b, Fig. 12), upon the same level, equally full of water and connected by a pipe; — no current flows from one to the other. But place the vessels at different levels, that is to say place b in the position of b', a current is established from the higher to the lower through the pipe. In a similar manner electricity will flow from the higher (positive) potential to the lower (negative) potential, and the pressure which urges the current forward is called electromotive force (B. M. F.). This force will depend upon the extent of difference of potential (level). Carrying further this water analogy, suppose the driving force to be not a difference of level but a pump ; — if the discharge pipe be carried round a given circuit back to the source of supply, both pump and pipe being full of water, the movement of the pump will cause the water to flow and produce a continuous current (Fig. 2). The motion of electricity resembles the current through this pump, and is subject to the same conditions, viz. that at every instant as much flows out of a given closed circuit as flows into it. For the pump substitute an electric generator, say a galvanic battery or a dj-namo, and a wire for the pipe, and electricity for the water, we have a tangible conception of an electric current. Placing side by side the electric with the hydraulic terms, it would be said that a certain number of pounds of pressure (volts) are required to overcome the friction (resistance) of the pipe (wire) in order that the water (electric current) may flow at the rate of so many gallons a minute (amperes). The larger the pipe (wire) the more water (current) could be carried, and the less will electricity.

Fig. 2. — Diagram to show analogy between a flow of water driven onwards by a pump and an electric current produced by the E. M. F. of a battery.

be the friction (resistance), and the smaller the pipe (wire) the less the current or gallons per minute (amperes). It is thus that by means of that quality which in hydro-dynamics is called pressure, and in electrical science electro-motive force, a current is forced forwards.

Every electric source, whether a battery, a dynamo, or Sources of other apparatus, may be regarded as a device for producing electro-motive force — in other words, for generating a force capable of starting or producing an electric current. All these devices depend upon the law of the transformation and conservation of energy. The methods of transformation for our purpose are (1) chemical (a primary or secondary cell), and (2) mechanical (fractional and influence machines, dynamo-electric machines). There are also other sources of energy capable of producing electrical forces which it is not here necessary to study. For example, the living body of an animal or plant, being the seat of physical and chemical phenomena, may be regarded as a source of electrical energy. So also is radiation, i, e. light or heat, an electrical source, a fact exemplified in the thermo-electric cell, or in the action of light upon selenium.

Of these various'sources of E. Mi F. the one most familiar to the medical man is [the primary or voltaic cell (Fig. 3).

Negative pole. ---_^S&\. «, (C^ Positive pole.

■nt. ^-. ; -^rJ|p7 .Jltl..: Negative element.

_. Bubbles of hydrogen.

Fig. 3.— A "Voltaic Cell."

Every such cell is made up of (1) a voltaic couple consisting of two " dissimilar electrical conducting substances ; " (2) an exciting substance called the electrolyte. If two such liquids or electrolytes are used, the cell is called "a double fluid" cell. The two substances forming the voltaic pair or couple are known as the dements of the cell, but sometimes the term element is improperly applied to the couple or pair of elements. It is usual to make voltaic elements in the form of plates or rods, and these are known as the positive and negative elements. Thus supposing that we constitute a voltaic cell by taking two sheets or rods of dissimilar metals, say copper and zinc, immersing them in an acid solution and connecting them by a metallic connection, a wire, the wire will at once manifest certain phenomena known as electrical. It will attract iron filings, it will deflect a magnetised needle, applied to a suitable liquid it will decompose the liquid, applying it to the tongue it will produce tingling or metallic taste. All this has been done by causing an electrical current to flow through the wire : in other words, we have established a difference of

THEKAPEOTIU ELEOTKICITY 11

2>otential, and current passes from the plate at the higher potential to the plate at the lower potential, i. e. current flows from the zinc to the copper through the liquid and from the copper to the zinc through the wire. Owing to the chemical changes that occur a continuous current is thus kept up in the circuit. A voltaic element may therefore be regarded as a device which by the expenditure of work (e. g. chemical change at the expense of a metal), keeps two bodies at different potentials, and thereby produces a flow of electricity through a conductor connecting one with the other. Electricity is, so to speak, liberated at the surface of the zinc ; it passes through the fluid of the cell to the copper, and the copper being joined to the zinc by a wire, the current flows through the wire and so completes a circuit. Without a complete circuit the electricity cannot flow. All the parts traversed by the current collectively constitute the circuit; the part of the circuit within the cell is the " internal circuit," the part of the circuit outside the cell is the " external circuit." When the continuity of the flow is broken the circuit is " open ; " when the conductor is continuous the circuit is said to be " closed." When the conductor has an exceedingly small resistance the circuit is said to be " short," — the battery is " short circuited." The plate from which the current flows within the cell is the electro-positive element (the zinc) ; the plate towards which the current flows is the electro-negative.

But the positive pole of the cell is the terminal of the electro-negative element, while the negative pole is the termination of the electro-positive element. In other words, in the external circuit the current flows from the copper to the zinc, whilst in the internal circuit it flows from the zinc to the copper. The positive pole is marked + , and the negative pole is marked — . When the cell is in action, i. e. ivhen it is furnishing an electric current, a chemical action is taking place between an electrolyte and one of the plates (the positive) which enters into combination with part of the electrolyte. The negative plate is not acted upon, but as tlie result of the decomposition of the electrolyte there is a tendency to evolve hydrogen at the negative plate; and if this be allowed to accumulate, the ability of the cell to furnish a current is materially decreased. And this decrease occurs not only because the film on the copper increases the internal resistance of the battery, but because the accumulation of hydrogen may for the moment be regarded as transforming the copper plate into a hydrogen plate, and hydrogen being electro-positive to zinc a current is set up opposing the original one ; this is called a counterelectromotive force (C. E. M. F.). 'Phis accumulation of hydrogen is called polarisation, and when a cell "gives out" from this cause it is said to be " polarised." Various forms of conducting substances, usually metals or carbon, are employed for the couples. Zinc is usually the positive element, the negative being carbon, copper, lead, silver, or platinum. The Leclanche cell. — That primary cell which for medical purposes is most generally useful is the Leclanche (Fig. 4).

Fig. 4. — A Leclanche cell.

Here the elements are carbon and zinc, and the excitant is an aqueous solution of chloride of ammonium. The chemical energy which produces the E. M. F. is got in the combination between the zinc plate and the solution of ammonium chloride.

The Daniell cell. — In that form of Daniell cell known as the " gravity " cell the two elements are zinc and copper ; but here there are two separate liquids, viz. a solution of copper sulphate which occupies the lower part of the cell, and a lighter solution of zinc sulphate which surrounds the zinc plates and floats upon the more dense solution of copper sulphate. This is an example of a " double fluid " cell (Fig. 5). The zinc plate dissolves under the action of

+1

Zinc.

Zinc sulphate.

Copper sulphate.

Fig. 5. — A Daniell cell.

the excitant to form zinc sulphate, hydrogen being set free. The latter displaces the copper from its solution and forms sulphuric acid and metallic copper; the acid passing back to the zinc, the copper is deposited upon the negative plate.

The Grenet cell. — The (xrenet or bichromate of potash cell has a higher E. M. F. (about two volts) than either of the preceding, and is suitable for furnishing a strong current for a short time, e. g. for cautery purposes or for lighting small lamps. The positive element is a plate of zinc ; the negative element consists of two plates of carbon. The depolariser is chromic acid (Fig. 6).

The persulphate of mercury cell is one having zinc and carbon as plates and persulphate of mercury as the excitant.

Tfie chloride of silver cell is a small cell hermetically sealed, whose elements are zinc and silver chloride. The two plates

Fig. 6. — A Grenet cell.

are separated by sheets of blotting-paper and saturated with a solution of chloride of zinc.

The Edistin-Lalande cell, an excellent cell for cautery or motor work, has its elements of zinc and copper ; copper oxide being- the dcpolariser, and the excitant being caustic potash. To prevent the formation of a carbonate by contact with the air a little heavy paraffin oil is poured over the top of the potash solution.

The Grove and modified Buusen cell. — The elements are zinc immersed in sulphuric acid, and baked carbon in nitric acid.

The "dry cell." — The term "dry" is not altogether appropriate, for although this class of cell does not contain free liquid, its action depends on the presence of a liquid electrolyte held by some absorbent material such as paper pulp, cotton, sawdust, &c.