There are several other effects of faradic electricity. As a general stimulant it is used in debility from any cause. As an excito-motor, the Bergonie method is used for the treatment of obesity by producing marked muscular con tractions without any effort on the part of the patient. Straps or weights prevent excessive movement of the patient's limbs. As a sensoil, stimulant it is used in sensory paralysis. It stimulates the secretion of glands. It is re vulsive or counterirritant in the later stages of inflammatory processes. ' Lumbago may be treated by applying faradic electricity with a dry wire brush electrode. It is excito-nutritive and tonic as a hydroelectric bath, in such dis eases as gout, diabetes, obesity, neurasthenia, convalescence from a long illness, and muscular atrophies. And the same baths are useful in combating various toxzemias. It may be used as a sedative.
The same conducting cords and electrodes may transmit to the patient a combination of faradic and galvanic current, in series; the De Watteville or current.
or De Watteville currents are applied by connecting a faradic and a gal vanic apparatus in series with a conducting cord leading from one pole of each to the different parts of the patient. One example of its use is in the treatment of spasmodic constipation. Large electrodes are over the abdomen and back; the faradic coil has many turns and the interruptions are rapid, producing very slight muscular contractions; and the galvanic current is quite a strong one, perhaps 30 milliamperes.
Sinusoidal currents are so called because the graphic curve in which forward motion repre sents time and up or down motion represents strength and direction of the current makes a sine wave. In effect it is an alternating current varying gradually as described• in one of the paragraphs on galvanic electricity, but these gradual alternations may be of any desired number up to 1,800 per minute. The alternating electric light current is a sinusoidal current of 1,800 cycles per minute and controlled by a suitable rheostat it can be used for treatment. The apparatus previously referred to and shown in Fig. 2 is used for changing the direct to a sinusoidal current of from 12 to 120 alterna tions per minute. It is useful as a local and general tonic application in a wide range of chronic general and local disease characterized by debility congestion, motor stony and pain. It is applied from the same kind of electrodes as the galvanic current.
Static Electricity.-- Lightning is an example of a discharge of static electricity and so is the spark which we produce by shuffling our feet on the woolen carpet as we cross the room in winter and then touch another person or a metallic object. A charge of static electricity
upon a hard rubber comb rubbed over our hair or over wool or fur causes the comb to attract small light objects to it. By suitable means any object may be given either a positive or a negative static charge. Similar charges repel each other and unlike charges attract, and if the charged bodies are light and freely move able, they will come together in the latter case and the two charges be more or less completely neutralized with an accompanying discharge which would be a loud spark between two large metal balls, or a silent and almost invisible brush discharge between two sharp metal points. Static electricity is of small quantity but of such high voltage that it tends to escape from a charged body; in fact no body can be charged at all unless it is more or less insulated. Con densers are sheets of metal separated from contact with each other by sheets of glass or some other insulating material. One metal sheet is charged from one pole of a static machine and the other is charged from the other pole. Owing to the great attraction which charges of the two opposite polarities have for each other, when in such close proximity each will receive a much greater charge than it could contain separately. And if both are discon nected from the source of electricity the two opposite charges are actually self retaining, so that either can be touched by a conductor with out losing its charge; but if a person touches both of the metal coatings at one time he re ceives a loud spark. Leyden jars with a dozen or more square inches of condensing surface are charged with a very small quantity of high tension electricity from a static machine and their discharge is used in electrotherapy under the name of the static induced current. A single electrode passes to the patient from the outer coating of a Leyden jar whose inner coating is connected with one pole of the static machine. The outer coating of the Leyden jar at the other pole is grounded (has a metallic connec tion with the earth). The patient need not be insulated. The distance between the discharging rods determines the voltage and consequently the degree of effect upon the patient. A wide separation of the discharging rods makes the static induced current suitable only for the ap plication of sparks which are powerfully stimu lant to buth striated and smooth muscles and to all other tissues.