High Frequency

A number of experimenters investigated the medical uses of high-frequency currents in the late nineteenth century including Nicolas Tesla [1856-1943], Paul Marie Oudin [1851-1923] and Jacques-Arsène d’Arsonval [1851-1940]. However, we can perhaps credit the development of the instrument commonly known as the ‘Violet Ray’ to Frederick Finch Strong as he claims to have developed the first glass vacuum electrode for use with a high-frequency apparatus in 1896.

If the general employment of a new device by members of the medical profession may be taken as evidence of its practical value, the Vacuum Electrode may be justly regarded as the most important contribution to Electro-therapeutic Technic since the advent of the High-frequency Current. …
The use of hollow glass electrodes exhausted to a so-called “Low Vacuum” for the administration of High-frequency Currents originated through certain clinical experiments conducted by the writer in the laboratory of Dr. J . P. Sutherland, who is at the present time Dean of the Boston University School of Medicine.

(Strong, 1908, p. 175)

The first glass electrode constructed by Frederick Finch Strong was made from a modified Geissler tube which had its “upper terminal covered by sealing wax and its opposite end fixed in an insulating handle” (Strong, 1908, p. 176). After this first construction, Strong went on to make a range of differently sized and shaped tubes to be used with the Strong-Ovington Static Induction and the high-frequency apparatus he had developed with Earle Lewis Ovington. The machine and the electrodes were put into commercial production by the Electro-Radiation Company of Boston in 1903 and by 1906 a battery-operated, high-frequency instrument was also available.

By the 1920s, a wide variety of glass electrodes – made from soda lime or borosilicate glass – had been developed for almost any part of the body, and high-frequency machines using glass electrodes were being applied in medicine, dentistry and some beauty salons. Devices were also made for domestic use after the First World War and had good sales even during the depression years of the 1930s.

The primary benefit of these high-frequency treatments was believed to be their effect on improving blood supply which brought nutrients to the skin and helped eliminate wastes.

When vacuum tubes are applied locally there is soon produced redness and hyperemia, with all of the resultant benefits on nutrition.
In short, the fundamental value of high frequency currents is their beneficial effect on all nutritive processes. Incidental to this we have increased oxygenation of blood and tissues, increased leucocytosis (and phagocytosis); and increased elimination.

(Eberhart, 1911, p. 66)

The fact that the sparks produced ozone would also prove to be useful in some treatments.

From the 1940s, the use of medical and domestic violet ray devices was on the wane: the medical profession was losing interest in electricity as a therapeutic practice and was moving towards pharmaceuticals; and the claims of the violet ray manufacturers producing devices for the domestic market were increasingly exposed as ‘exaggerated’. In the United States, government prosecutions of violet ray manufacturers for false and misleading claims were physically removing many from the market. Although their use in medicine, dentistry and in the home largely ceased, they remained in operation in beauty salons and continue to be found in some to this day.

High-frequency machines

A typical high-frequency machine consist of a central unit connected to a hand piece into which glass electrodes of various shapes can be inserted. It produces a high-frequency, alternating current with a high voltage but low amperage, meaning that if it is applied to the body without sparking it does not result in shock, pain or injury.

Glass electrodes

The glass electrodes used in high-frequency treatments came in a variety of shapes and configurations. In the past they were filled with mercury vapour, neon or argon gas but most were simply made with air in a partial vacuum, the strength of which would determine the colour of the light generated when the power was turned on.

The vacuum of these electrodes or tubes varies from a very low to a very high degree. The degree of vacuum may be estimated by the color which is emitted. One of low vacuum emits a reddish glow and is the one of choice where relief from pain is the object to be attained. One of medium vacuum emits a bluish tint and one of high vacuum has a whitish appearance.

(Grover, 1922, p. 135)

As indicated above, different colours were believed by some to have different healing effects, an idea carried over from prevailing notions regarding the therapeutic effects of differently coloured light.

The red or red-pink vacuum besides giving off more heat, is sedative and useful in painful conditions and in acute diseases and inflammation.
The medium, blue, or blue-white vacuum gives off some chemical rays, and is more appropriate in chronic conditions. It is often employed where the white vacuum would really be indicated, as this contains not only blue and violet, but also some ultra-violet rays. All chronic ailments, where the vitality is impaired, skin diseases, indolent ulcers, etc., call for the employment of the white or blue-white tube.

(Eberhart, 1911, pp. 52, 55)

See also: Red Light, Blue Light

Although the range of glass electrodes supplied with medical high-frequency machines could reach twenty or more, the number of electrodes used in Beauty Culture was normally much less than this and included:

Bulb electrode: Used for facial and body work.

Bulb electrode

Saturator electrode: Held by the client during indirect treatments.

Saturator electrode

Fulguration electrode: Used to generate an intense concentrated spark to remove skin blemishes like moles and warts.

Fulgurator electrode

Neck electrode: Originally used medically for goiter treatments but could be used on any curved surface.

Neck electrode

Rake electrode: Used to treat alopecia and other hair problems.

Rake electrode

High-frequency treatments

All the high-frequency treatments carried out in beauty salons came directly from applications developed by the medical profession.


Above: 1915 A table of high-frequency treatment methods used in the medical profession.

Salon treatments

The two high-frequency treatments commonly used in salons are today known as Direct and Indirect High Frequency, although the later is sometimes referred to as a Viennese Massage.

Direct Method

In this treatment the operator holds the glass electrode and applies it upwards and outwards over the client’s face. When in close contact with the skin, heat is generated at the point of contact with the electrode. However, if a small gap is included, sparking between the glass electrode and the skin ionises the air producing ozone along with nitrous oxide, both of which have a germicidal effects. The procedure is therefore used in the treatment of pimples but acne but other skin blemishes like psoriasis were treated in the past. On occasions direct high frequency has also been applied after hair has been removed.

To help generate an even spark the electrode is often applied over gauze. This could be wrapped around the electrode but in most salons it is laid across the client’s face.

Indirect Method

In this procedure – also known as Viennese Massage – the client holds the saturator electrode while the operator massages the client’s face. As the operator massages the skin, the current flow between the client’s skin and the operator’s fingers heats the underlying tissue, an effect that could be increased if the area of contact between the operator and the client was reduced by using fewer fingers.

As with all heat treatments, the warmth was said to stimulate blood flow and therefore be good for the skin. The procedure was also regarded as relaxing but for many clients the use of electricity often made them feel nervous and therefore tenser.

Redundant salon treatments

Three other procedures were commonly applied in the past but are no longer in general use today.

General electrification

This treatment had its basis in the idea that electricity is a ‘life-giving’ energy source. In the procedure the client was given the saturator electrode to hold onto and, after the current was turned on, was left to relaxed while her body was supposedly invigorated by being ‘charged with electrical energy’.


This procedure was used on moles, warts and other skin blemishes using a direct stream of electric sparks from a specially designed fulguration electrode which had a wire extruded from its end point.

The orifice of the glass tube is placed on the growth and the current is turned on very gradually, thus causing local anathesia and making the operation practically painless.
The sparks must have a whitish appearance; if the become yellow and flame like, the result will be a burn, like with ordinary cautery and there will be an odor of burning flesh. That is not true fulguration.
A wart will first turn pink and then blanch. The time required varies with the size and may require more than one application especially if more than one blood vessel supplies nourishment, for all must be plugged or coagulated.
When moles are treated, a serum may exude after the first treatment and eventually the whole top may slough off.

(Blood, 1932, p. 321)

An alternative method was to have the client hold the saturator electrode while the operator generated a spark indirectly using an all-metal electrode.

Although fulguration was described as painless it seems unlikely that this was the case. Given the risk of skin damage, pigmentation changes and scarring some beauty experts advised against it.

Even in the hands of an otherwise competent dermatologist, the use of the fulgeration point has often caused a hideous and hopeless pitting and scarring of the skin. It is, therefore, best left to those who have the mechanical skill as well as the correct knowledge of this operation.

(The science of beautistry, 1932, p. 209)

Understandably, most therapists today would consider the procedure far too risky to be carried out.


High-frequency machines were also used in the past in conjunction with drugs like cocaine or chemicals like iodine. On occasion the impression was given that the high-frequency electricity helped push these substances into the skin. As high frequency is an alternating, not a direct current, this was not possible but the idea persisted.

There is a so-called cataphoric glass electrode made and recommended by some for the ionization of drugs, but it is practically useless since a high-frequency current is an alternating one and has but little, if any, ionizing power. In order to drive medicaments into the skin a direct current is necessary.

(Grover, 1922, p. 136)

See also: Iontophoresis and Desincrustation


Given that the spark from a high-frequency machine generates ozone, it was not long before glass electrodes were developed that could be used to inhale ozone directly into the nasal passages and lungs. This medical practice was used to treat a variety of illnesses from colds through to asthma but has fortunately been discontinued.

In Beauty Culture, high-frequency sparks were added to vapourising machines – today we would refer to them as steamers – so that the client’s face was bathed in a spray of steam and ozone. These can still be found in some salons today although they have been banned in some jurisdictions. Although the amount of ozone produced by a steamer is low, given that ozone is both an irritant and a poison it is probably best to avoid such treatments even if they are still legal.

See also: Vapourisers (Steamers & Atomisers)

Updated: 31st July 2017


Blood, I. H. (1927). The cosmetiste: A handbook on cosmetology with special reference to the employment of electricity in the care of the hair, scalp, and face at the direction and under the supervision of W. M. Meyer (4th ed.). Chicago, Ill: The W. M. Meyer Co.

Eberhart, N. M. (1911). A working manual of high frequency currents. Chicago: New Medicine Publishing Company.

Electrotherapy museum. Available from http://www.electrotherapymuseum.com

Grover, B. B. (1922). Handbook of electrotherapy. Philadelphia: F. A. Davis Company.

Monell, S. H. (1910). High frequency electrical currents in medicine and dentistry. Their nature and actions and simplified uses in external treatments. New York: William R. Jenkins Company.

The science of beautistry. Official textbook approved for use in all the national schools of cosmeticians affiliated with Marinello. (1932). New York: The National School of Cosmeticians, Inc.

Strong, F. F. (1908). High-frequency currents. New York: Redman Company.