also has a sedative action upon nerve endings. Conversely the negative pole has no antiseptic action but releases nascent hydrogen. It does not constrict but softens tissue and consequently promotes the flow of blood; instead of being an astringent, is the opposite and will cause hemorrhage. Moreover, the action of the negative pole on nerve endings is the opposite of the positive pole and is it therefore quite irritating. These chemical effects of the galvanic current are utilized in the treatment of different conditions. Another effect is demonstrated by Farady's well known 'ice pail experiment' which showed that like charged bodies repel each other. This makes it possible to take certain metals that are electrically positive and by placing them on the positive electrode connected with a source of galvanic current they are electrically forced into the tissues to a slight depth. In the same way negatively charged substances, such as alkaloids and bases, can be repelled by the negative pole and so forced into tissues. Contrary to the old original idea these substances cannot be passed entirely through a part such as a knee joint or shoulder but drugs can be forced sufficiently deep that they are absorbed by circulation. The sinusoidal current, reversing its polarity at each phase, does not have any of these polarity effects and is a means whereby we can utilize the power of the galvanic current to cause muscles to contract without considering such effects. There are other machines made which cause the galvanic current to surge in such a way that there is a gradual or abrupt increase and decrease in strength. These 'Surging Currents' can be controlled in any way so that we can get all kinds of waves that are applicable to certain sets of muscles. The sinusoidal current may be made to alternate in its direction of flow as quickly as is desired and when it is reversing at the speed of sixty times per second, it then becomes what is commercially known as the 'alternating current.' This ordinary alternating current is therapeutically useless so that machines giving a regulation A.C. are of no use in medicine and surgery. If, however, these alternations are trebled we then get a current that is useful in stimulating muscle and as we increase the speed of alternations until they get a million or more per second, we arrive at the currents known as 'high frequency currents.' Two variations of interrupted galva nism which are used in Europe but not so often in this country are the Leduc and the Lapicque currents. The Leduc current is an extremely sedative form of interrupted galvanism, where the time of the complete cycle is divided into tenths; that is, the period of rest between shocks is nine times the duration of the period of stimulation, but the shocks are administered at the rate of about two hundred per second, consequently, they are of very short duration. The Leduc current has been used for some time for a sedative form of stimulation of muscle. Some years ago Dr. Rabinowitz used it on the brains of rabbits and was able to produce an electrical form of sleep. The experiment gained great publicity, but when it was tried upon human beings, the same effect was not produced and consequently its use has been dropped. The Lapicque current is administered by a special apparatus that causes the make of a current to be slowed up so that when the circuit is closed, the current reaches its full strength very gradually and then slowly drops to zero. It has been used a great deal in Europe because it is found that when used in a weak form, paralyzed muscles will react, whereas normal muscles will not. For this reason it is helpful in showing patients just what motions they should practise to re-educate paralyzed muscles. The use of this current is considered a better means of telling whether or not nerves are degenerated than the formerly accepted method of using ordinary galvanic electricity to produce the so-called Reaction of Degeneration. High frequency currents in electrical medicine are currents that alternate in their direction of flowing at a speed greater than five thousand times per second. Over thirty years ago d'Arsonval discovered that if such a current is administered to any part of the body the stimulation is such that it produces no nervous nor muscular response. He gradually worked up methods of producing these high speeds of alternation, and work along this line has progressed until now there are machines which can produce alternations at the rate of over three million times per second. This current is produced by connecting a solenoid or helix with the outer sides of Leyden jars or other condensers into which is led a current of high voltage. As a shunt in this high voltage circuit, that is connected with both wires, there is a spark gap interposed which when opened produces a resistance of air, causing the current to fill up the Leyden jars or condensers to a sufficient amount to break down the air resistance of this spark gap. Remembering the peculiarity of inductance mentioned above, one can realize that the current spread out upon the inner coatings of the Leyden jars will by inductance produce a current on the outer coatings. When sufficient voltage or pressure is accumulated in the primary circuit to break down the resistance of the spark gap, the condensers are then discharged and the current produced on the outer side of the Leyden jars connected with the helix will race back and forth through the helix or solenoid and produce a current of very high frequency. Each discharge of the inside of the condensers will produce a like high frequency current in the solenoid. If wires are connected with the ends of the solenoid, the current will pass from one wire to the other which is a high frequency current. It is a well known law of electricity and physics that any portion of an electrical circuit that is of greater resistance than the rest will slow up the passage of any electrical current and when energy in motion is slowed up, heat is produced. This factor is the cause of the use of high frequency electricity today, for parts of patients' bodies are purposely introduced into the circuit of high frequency electricity and heat is produced throughout the path in the tissues through which this high frequency current passes. The entire path in the body is not heated equally because the normal protective mechanism of the body which helps to overcome any kind of irritation, such as heat, causes the blood vessels to be dilated so that much of the heat produced by the high frequency current is carried away to cooler parts of the body. However, in the centre of the path farthest away from the cooler surrounding tissue, it is possible to get almost any degree of heat desired. This point is in the area of the greatest flow of current and varies in its position with the size of the electrodes used. It is easy to see that with the same amount of current on each electrode, if they are of different sizes, the density of current on the smaller electrode will be so much greater than on the larger that the area through which the current flows most directly and forcibly will be nearer the smaller electrode. By means of this high frequency technique, generally called 'Diathermy,' heat has been produced in tissue up to a temperature of 270° F. For the treatment of deep-seated cancers this current frequently is used to actually cook and destroy the tumors under the skin without affecting the skin on the surface. This method, however, is not in vogue in this country. Diathermy is always created with the d'Arsonval current, where two electrodes are used on opposite sides of the part treated. It is administered for conditions such as pneumonia, bronchitis and for heating up the kidneys or other such purposes. If the same kind of current is used and one electrode is very large and the other a needle point, it is easy to understand that the greatest action of the current will be immediately beneath the point of the needle. This method of treatment enables one to destroy large areas of tissue with the needle and microscopical sections of tissue so treated show that the tissues are cooked and coagulated. By some authorities this technique is known as Electrocoagulation. Autocondensation is another method of administering the d'Arsonval current, where one terminal is connected with a series of metal plates which are placed on the under side of a nonconducting material such as thick glass or a fibre cushion through which the current cannot High-Frequency Currents. Treatment in Auto-conduction Cage pass. The other terminal of the machine is connected with a handle which is held by the patient and in this way the patient becomes a coating of a Leyden jar or condenser and consequently the current is condensed in the patient, hence the name. Autoconduction is still another means that was originally utilized to administer the d'Arsonval current generally, but is not nearly as effective as autocondensation. This techInique is carried out by placing the patient within a very large solenoid, as illustrated, when the current passing through the solenoid electrically creates a current in the patient, who is a resistance and consequently bebecomes heated. Autoconduction is not used in the United States but is sometimes utilized in France. If one realizes that the use of a solenoid practically constitutes the introduction of a transformer in the d'Arsonval circuit, it is easy to realize that continuing on the solenoid beyond the terminals used for the d'Arsonval current will further 'step up' the high frequency current in voltage so that it is possible to produce a current of extremely high voltage and of a still higher frequency. A wire connected with the end of this extended solenoid will be charged with a current of such high voltage that when brought near an uncharged body, such as a patient, the current will immediately leap across an air space in its endeavor to fill up this empty 'capacity' (the patient). Such an arrangement creates the current first described by Oudin and is known by his name. This current, being of very high voltage and able to break down different resistances, has been extensively used to create a pleasant form of heat on the tissues of patients by the use of various kinds of applicators. The most popular applicator used, but now known to be the least effective, is the glass electrode which is sealed and exhausted to a partial vacuum. (See illustration.) These vacuum electrodes are essentially condenser electrodes and Oudin current is condensed along the inner surfaces of the glass, increasing its power to jump the small intervening space and penetrate the glass of the applicator, thus creating a sensation of heat upon the patient's skin. During the passage of this current through the partial vacuum, a color is created which has been misnamed 'violet ray.' The color has absolutely nothing to do with the effects produced and varies greatly from red through purple to blue and if the vacuum is as high as that used in x-ray tubes, the color assumes an olive yellow color. It must be understood that any of the light created in these electrodes is merely an incident in the transmission of the current and the so-called 'violet ray' that has been commercially popularized in barber shops and beauty parlors, is of absolutely no benefit. In the last ten years these glass vacuum electrodes have been improved to a great extent by coating their inside surfaces with silver and having them nonvacuum. That is, the end is opened so that the current can spread along the metallic silver with greater ease. The nonvacuum electrodes produce a surface heat which is much greater High Frequency Vacuum Electrodes and Insulated Handle and more effective than that produced by the old-fashioned glass vacuum electrodes. These glass electrodes may also be used as one electrode in a d'Arsonval circuit but they are generally used with the Oudin current. In like manner a needle may be used with the Oudin current for an effectiveness somewhat similar to its use with the d'Arsonval current. The effect, however, is quite different in its intensity because the high frequency current running at a higher voltage and consequently lower amperage does not produce the marked coagulating effects produced by the d'Arsonval current, but instead the Oudin current produces a drying up of tissue and dehydration without coagulation and destruction. Consequently, William L. Clarke in 1912 called this method of administering the Oudin current 'Electrodesiccation.' Due to the minimum amount of actual destruction of tissue there is much less scar formation after its use and electrodesiccation is the method of choice in destroying superficial bits of tissue such as warts, moles and skin cancers with the best cosmetic result. of great use in high frequency work today. Some of the machines manufactured can supply it but it is more of an accessory than a necessary part of the machine. On the whole high frequency electricity is used generally for the production of heat within tissues, but experiments past and to come undoubtedly will demonstrate that besides creating heat in normal tissues the high frequency currents have a profound effect upon tissues and general metabolism. As yet these effects cannot be recorded but they undoubtedly will be proven and much of the knowledge of the action of high frequency will be amplified when these constitu Modern Static Machine current also created heat as well as the cutting effect, the machine was never put into production and was dropped. Some years later a similar sort of machine using a three-element vacuum radio tube instead of a spark gap was brought out in Europe and imported to the United States. This machine produces a cutting current without as much coagulation as the original machine but still far from ideal. Suffice to say that when the current is working at the correct oscillations, it will cut through tissue. A similar current can be produced by a high frequency machine by using a spark gap instead of a radio tube, but the physics and elec static machine. Such machines today are generally of ten to twenty-four plates of glass revolving near some stationary plates of glass. The friction of the chemically dried air within the cabinet causes the formation of the frictional or Franklinic current that has been misnamed static electricity. The term 'static electricity' probably comes from the fact that it will remain stationary or static within a machine and when the plates are reversed, it will be produced without any chemical activity. Static electricity can be produced by rubbing the feet along heavy carpet and is purely the result of friction. Electrically it is described as a current of extremely high pressure or voltage and of minimum volume or amperage. It is employed to get the effects of this current of high voltage and consequently, being energy working under great pressure, one gets little electrical effect but merely the decongesting effect of high pressure energy. There are three types of static machines in use. One is the Wimshurst in which there are no stationary plates but only alternating plates revolving in opposite directions, while brushes that collect the current are in actual contact with the plates. This kind of machine is capable of generating its own current, but each time the current is generated there is a great probability that the plates will assume their charges in reverse of what they were when the machine was stopped. Inasmuch as the polarity of the static current is essential in its use, the machine is not practical for general use today. Similar to the Wimshurst machine is the Toepler-Holtz which is made up of revolving and stationary circular plates. also with friction upon the surfaces of the revolving plates. This type of machine is likewise self-charging and will not keep the current flowing in the same direction if the machine is stopped. Consequently it is not dependable enough for modern therapeutic use. A third kind of static machine is known as the Holtz machine, in which the stationary plates are placed above and below a rotating shaft upon which the circular plates are stacked so that the circular plates rotate near and between the stationary plates. In the Holtz there is no actual contact between brushes and plates and the entire friction is caused by the rotating plates passing very close to the stationary plates with only chemically dried air between. The Holtz machine has one disadvantage which is that it will not create its own charge although it will hold a charge under favorable conditions for many months. Its great advantage is that when once charged it will always keep its polarity and it is not necessary to test the polarity each time it is used. The modern machines are made of a combination of a large Holtz model and Wimshurst model of two plates on the side so that a static charge can be created by the Wimshurst and transferred to the larger machine when the larger machine has lost its charge. As stated in the section on high frequency electricity, there must be some constitutional effects created by the passage of electrical energy through the body but as yet experimental evidence does not permit the statement of just exactly what these effects are. Consequently the static current is used for a thoroughly admitted effect of decongesting tissues and forcing out infiltration. This is accomplished today by three regular methods, of which there are many variations originated by many workers in static electricity but all applications of the three basic ways. One of the original workers in static electricity in the United States was Morton, who found it was possible to place a patient in the circuit as a condenser and that by charging and discharging this patient, a pronounced mechanical effect was produced, which in turn caused marked decongestion. This application of the current is known as the 'static wave current' or sometimes the 'Morton wave.' All applications of the static current are given to the patient, who is seated upon a wooden platform with ten-inch glass legs. thus insulating him from the earth. In practically all applications, the pole not connected with the patient is attached to a ground. The static wave current is administered by connecting a metallic plate with the positive pole of the static machine and this plate is applied to the part of the patient's body where the decongesting effect is indicated. The negative pole of the machine is grounded and the machine is made to revolve by an ordinary electric motor which is connected to the axle of the machine by means of a belt. The sliding rods of the static machine are separated until the charging and discharging of the patient, who is a condenser, is accompanied by pronounced muscular contraction beneath the area covered by the electrode. It is frequently the custom to connect Leyden jars either with the grounded pole or with both poles of the Imachine when the static wave current is administered. If two Leyden jars are used the outer coatings must be connected. The addition of these Leyden jars does not vary the static current but merely increases the capacity of the machine and consequently slows up the sparking across the spark gap, causing a greater period of rest between contractions of the patient's tissue. Most workers in static electricity agree that this slow contracting and relaxation of the tissue is more beneficial than a series of stimulations as produced by a sputtering discharge across the spark gap. However, if the Leyden jars are not used and one wishes a more definite force in the amount of stimulation given, many contrivances may be used that cause a leak of current from the patient to the ground. Such apparatus have been devised by Humphris, Travell, Pedersen, Turrell and Massey all characterized by their own peculiar differences. If the static wave current is administered with the patient connected with the negative pole, it produces a very marked irritation of tissue and is extremely uncomfortable to the patient. 'Static sparks' is another method of administering the static current, where the platform on which the patient is seated is connected with the positive pole, the negative pole being grounded. From a separate ground a ball-tipped metallic electrode is approached to the patient and the current in the patient grounded. With this method of treatment, the sliding rods are pulled widely apart so that no current passes between them and the patient, being filled with positive electricity, receives a shock which is harmless and moderately painful, at the point where the spark emerges and grounds through the balltipped electrode applied by the operator. It is the general custom to have the patient connected as stated above because it is felt that discharging the patient to the earth is much better than having the patient connected with the negative pole and applying positive current which has previously gone to the earth and is returned to the patient by the ball-tipped electrode. This process of administering static sparks gives a pronounced contractile and decongesting effect which is much stronger than that produced by the static wave current and cannot be borne for the same length of time as the milder wave current. Static effluve is administered by connecting the patient, seated upon the platform, directly with the negative pole of the machine, and the positive pole being then grounded by a separate ground chain, the current is led through one of the many kinds of applicators used and goes to the patient as an effluve or spray, which is extremely sedative and powerful as a decongester and especially indicated for painful, indurated areas. The applicator most used was originated by de Kraft and is known as the 'pencil brush applicator' due to its similarity in shape to a pencil. It is made of a fibre tube tipped with a sharp metal point and filled with asbestos. If the patient is not arranged as above stated, i.e., connected with the negative pole, the static effluve will not work because the static current always goes from the positive to the negative pole. Another form of the application of the static current is the static bath, where the patient is connected with either pole and the other pole grounded. The rods being widely separated cause the current to leak from all parts of the patient to all parts of the room. This has a sedative effect upon the sensory nerve endings in the skin and makes the treatment extremely restful and quieting to nervous patients. The method, however, is most effective in a dark room and consequently smacks much of psychotherapy. A like qualification of effectiveness might be applied to use of the static crown breeze, where a patient is similarly arranged but instead of the positive pole being grounded, it is connected with a brass crown which is held some distance above the patient's head and the current leaking from the patient to the crown also produces a marked psychic effect. Before low voltage currents were used in order to get marked stimulation of muscle the technique known as the application of the static induced current was in vogue. This current was applied by means of two electrodes which were connected with the outer coatings of the two Leyden jars. At each spark across the spark gap the current was induced on the outer coats of the Leyden jars which caused a pronounced contraction of all tissue interposed. This static induced current is not a static current at all but is essentially a high frequency current administered to the patient in a series of shocks, which cause a contraction of tissue equally under both electrodes because the current oscillates between the two. All electrical modalities should be administered only by medically trained physicians, whose knowledge of the underlying pathology is sufficient to make them understand why certain electrical modalities should be used. With the exception of the specific effect of ultraviolet light on rickets and the actual destruction of tissue by means of electrodesiccation or electrocoagulation, there is nothing in the field of electrotherapeutics which can stand alone as a method of cure for any diseases. Electrotherapeutics is only a modern method of applying the physical force of electricity as an added tool in the armamentarium of the modernly trained physician. Electrotherapeutics, however, is not essentially a modern method of treatment. It has been used, as mentioned above, since 1600, but with the training of the physicians and scientists of today, the actual workings of the electrical currents within and upon the body are much better understood and hence the consideration of electrotherapeutics is now more seriously contemplated. The physician of today is realizing more and more that operation and medication are not the only means of helping in curing pathology and with the more rational understanding common: (1) holders for the Important developments in the history of arc lamps are summarized in the following table: Important Facts in the History of Arc Lighting* Carbon arc discovered.. Discoverer or Inventor Date Place Sir Humphrey Davy 1801 England Sir Humphrey Davy 1821 England Brush 1876 United States Marks 1893 United States Bremer * Reprinted_by_permission from 'Illuminating Engineering,' by Cady and Dates, published by John Wiley & Sons, Inc. of the use of physical measures, such as electricity, one can often look forward to better and quicker return to health when these methods also are used. Electric Lamps. Electric lamps fall naturally into three classes: (1) arc, (2) incandescent filament, (3) gaseous glow-lamps. Of these the second is by far the most common, the arc having in recent years become obsolescent, and the gaseous being thus far restricted to novelty lighting and to certain special purposes. Arc Lamps.-This is the oldest form of artificial electric light. If two carbon rods, connected to the terminals of a battery or generator developing an electromotive force of 50 or more volts, are brought into contact and are slightly separated, current continues to flow across the gap, producing a brilliant light. If the carbons are horizontal the glowing vapor curves upward in the form of an arc, hence the name. The phenomenon was first exhibited in public in 1808 by Sir Humphrey Davy, who is credited with its discovery in 1801. Davy used tips of wood charcoal, with a battery as the source of current. Beginning with 1844, gas-retort carbon rods were used with regulating devices to keep the arc at the proper length. Some use was made of this new illuminant for street lighting but so long as primary batteries were necessary the cost was excessive. About 1880, with the development of the dynamo, the use of arc lamps increased. The various forms of arc lamp all had certain features in In the old open arcs, which in the United States were usually operated in series on a constantcurrent circuit of either 9.6 amperes or 6.6 amperes, there was a rapid burning away of the tips. The positive carbon was consumed at the rate of about one inch per hour; the negative, if of the same diameter, about half as rapidly. By enclosing the arc in a long narrow glass globe with an opening at the top through which the upper electrode passed with only a slight clearance, the life of the carbons was increased to about 100 hours or longer. The saving in cost of labor for replacing carbons was partly offset by decreased luminous efficiency. In the direct-current arc the positive tip soon takes the form of a vividly incandescent crater from which 85 to 90 per cent. of the light is emitted; the remainder comes from the negative tip and the arc stream, which latter imparts a distinctly violet tinge. In the flame-arc the carbons are impregnated with calcium fluoride or other salts. These are usually carried in a core softer than the outer shell. The arc then takes the form of a luminous flame much longer than the carbon arc, and with much higher efficiency. The color depends on the chemical used, calcium fluoride giving an intense golden yellow, with an efficiency approximating three times that of the open carbonarc. Barium and strontium salts have been used to secure rosecolored and white, a brilliant white being also obtained with |