and, owing to its peculiar construction, there is claimed for it a very great range of power. The discharge is readily varied. without the use of rheostats from a few hundreds of volts to hundreds of thousands at will, enabling light or heavy Crookes tubes to be used.

Prominent among the novel and unique features incorporated in the instrument and deserving mention, are the hand oscilla

tor and pneumatic switch. The hand oscillator is a simple device that entirely frees the cords connecting the electrodes with the rest of the apparatus from the disagreeable sparking, etc., so often present. The pneumatic switch is arranged to enable the operator to have perfect control of the apparatus, even though both hands are engaged on the patient.

The instrument operates on either alternating or direct currents, is readily connected to the lighting circuit by means of a cord and plug, and owing to the readiness with which it may be taken from place to place, should open up a large field of work, it being very desirable in many cases to treat patients at their homes or at their bedside, rather than at the office.

As nothing has been sacrificed to make it portable, either in power, durability, or insulation, it is well suited for general office work.

THE SHELTON VIBRATOR.

The Shelton Vibrator is now recognized by medical authorities and leading instrument houses throughout the United

States and Europe as a standard instrument for physicians' use. It is light and portable,-only weighing three pounds,and durable, being built by the largest electrical plant in the world. The vibrations are powerful from a heavy percussion stroke, to a wave, rotary or (Swedish massage) movement. Also a high frequency pulsation-ranging on a sliding scale from five to thirty thousand vibrations per minute-instantly regulated while in motion by the slightest touch of the operator and with absolutely no vibration in the handle.

It is designed solely for physicians' use, all points having been taken into consideration, with a view of placing, before the profession an instrument perfect in every detail.

The Shelton machine is made in four styles, No. 1 being designed for either the alternating or direct current, and is put up with four applicators in a velvet-lined carrying case.

The No. 2 outfit is the alternating current machine with resistance and it will operate on both the direct and alternating circuits, it being possible to control the speed of the motor.

This is also furnished with four applicators. It is a great advantage to have a machine that will operate on either current, as a physician might wish to take the machine to a patient where the current differs from that in his office, or he may move to a place where the same difference exists.

The No. 3 outfit is the same as the No. 2, except that it is furnished with nine applicators, and the No. 4 outfit is the same as No. 1. except that it has a full set of applicators. Cuts of the applicators and machines are shown herewith.

The machine is made by the Fort Wayne works of the General Electric Company for the Shelton Electric Co., Chicago, Ill., and the eastern agency is located at room 1018, 150 Nassau St.

THE DOUBLE VALVE TUBE RECTIFIER.

Two separate tubes joined together for convenience. The following description of one will answer for both.

This valve tube or rectifier is a modification of the original Villard tube of the French.

The vacuum is about one-half of that required for an X-ray tube; the essential difference being in the terminals, one terminal ending in a plain aluminum wire, requiring no disk or

other ending for its termination. This end of the tube must be attached to the positive end of the secondary coil; the other end of the valve tube ending in a heavy aluminum spiral. The larger the size of the wire and the greater the number of turns of this spiral, the more successful are the results. The spiral ending must be attached to the anode of the X-ray tube.

This tube is manufactured by the Wappler Electric Controller Co., 177 East 87th Street, New York.

Advanced Therapeutics

VOL. XXIV.

AUGUST, 1906.

No. 8.

ON THE

IMPORTANCE OF DIFFERENTIATION

IN THE USE OF ELECTRIC MODALITIES.*

BY A. D. ROCKWELL, A. M., M. D., NEW YORK,

Neurologist and Electro-Therapeutist to the Flushing Hospital, etc.

The term electricity is, in a way, generic and includes a wide variety of manifestations. In atmospheric electricity we see in highest degree these varied manifestations, magnitude, voltage, with infinite rapidity of oscillation, and the combination is simply deadly in its effects. Man has in a measure triumphed over this lethal energy, has analyzed and dissected it, as it were, and made it subservient to his uses, both commercially and therapeutically. In therapeutics we utilize it in the form of the continuous current, one manifestation of which is represented by what is commonly termed the galvanic current with its magnitude and low voltage, the other by the faradic current representing a far higher voltage with negligible magnitude.

Static electricity represents a still higher voltage, with practically no magnitude, while high frequency currents are still other manifestations of electric force, with electro-magnetic induction effects, kindred to those from the primary circuit of an induction coil, but widely differing in the degree of their physical, physiological and therapeutic effects. The principles of the ordinary induction coil are here all carried out, the jars taking the place of the cells, with a spark gap instead of a rheotome or current breaker. Like the ordinary faradic current, high frequency currents require for their development some form of initial electric force transmitted through the medium of condensers, coils of wire of varying thickness and length, and like the ordinary faradic current, the relationships of magnitude and tension depend altogether upon the character of the initial force and the intermediate coils of induction. In the same way, therefore, as the faradic current can be made

*Read before the American Electro-Therapeutic Association, Sept. 19, 1905.

to differ widely in its effects-according to the character of its coils-so, too, with high frequency currents. It is the degree of the step-up process through which high frequency currents are obtained that determines their efficiency, and as there seems to be no uniform constructive standard among manufacturers, it is difficult, if not impossible, for different workers to compare results with absolute accuracy.

Now, if there is any one thing more than another that has retarded, still retards, and will continue to retard, the all-round and scientific development of electricity in medicine, it is the increasing tendency to neglect the subject of differentiation in the selection of the various electric modalities. Neglect is but another name for ignorance of the subject neglected, and ignorance leads not only to unsatisfactory therapeutic results, but in the case of so potent an agent as electricity, to damaging results that may be more than transient. I venture to say that the majority of physicians who are doing electro-therapeutic work to-day, whether as a side issue in general practice, or as in some sense specialists along this line, have failed to take a broad and comprehensive survey of the field upon which they have entered, and would be unable to define the principles which underlie the therapeutic uses of this agent.

The individual experiences suggesting these reflections have been many and frequent, one of the more recent of which I beg leave to offer as my text:

A physician who had made use of electricity consulted me some time ago as to its use in a case of pelvic pain. I suggested the high tension current by the bipolar method. He attempted the treatment, but succeeded only in inducing in his patient, a delicate, nervous young woman, a most violent tonic muscular contraction. The result was hysteria, increase of pain, and a general nervous breakdown, from which the victim has by no means yet recovered. In addition, the doctor was threatened with legal proceedings, which have been prevented only by much tact, aided by some substantial pecuniary consideration.

In this case, the trouble was caused through ignorance of the relation of quantity or volume, and tension, and the measure of their combined or respective influence on living tissue, together with unfamiliarity with the mechanism of the apparatus employed. It was desirable to produce a sedative effect through the use of the high-tension coil. To secure this effect and avoid