Mechanical Vibration
M. L. H. Arnold Snow, M.D.

Chapter 4

The Procedures of Mechanical Vibration

    MECHANICAL-VIBRATION OR VYBRA-MASSAGE in the modern sense produces vibration as understood by physicists, whether that motion be to and fro in one plane, up and down, percussory, oscillatory, mixed recurrent or rotary.  When a vibration is induced through connected particles of matter a succession of waves are set in motion which form a line known as the wave line.  From a fixed point on one wave to a corresponding point on the next is one wave length.  When several wave lengths send impulses throughout a given area, motion from each follows resulting in interference.  Interference may increase, decrease, or inhibit motion.  It may cause areas of different degrees of vibration, and in membranes, etc., it may result in vibration in segments or stationary vibratiolas, the points of least vibration being called nodes, the points of greatest motion, antinodes, and the portion between two nodes, a ventral segment or loop.  The resultant wave will be longitudinal if the particles in vibration and the wave path be in the same direction, or transverse when they are in opposite directions.  The rapidity of the wave transmission is increased with the increase of the elasticity of the medium as it more easily transmits "waves made up of condensations and rarefactions," hence the elasticity of the region treated will influence the effect.  Therefore with a given rate of vibration one tissue or organ may have few waves transmitted in a given time, whereas another may have many consisting of nodes, antinodes, and loops produced with marked rapidity under which conditions physiological inhibition may be induced instead of stimulation.  It is also possible in an organization so intricate and complex as the human body that sympathetic vibrations may be elicited in certain parts in harmony, i. e., having the same periods of vibration.  When the vibration period peculiar to a particular part is not recognized, mechanical vibration may cause forced vibrations.  Gage [Elements of Physics] states that "When a vibratile body is compelled to surrender its own vibration period and to vibrate in an arbitrary manner imposed upon it by another, the phenomenon is known as forced vibrations," which may occur when mechanical vibration is applied to a part.

    THE STUDY OF HARMONIC VIBRATION is a field yet requiring much investigation, but in connection with it, it must be remembered that an increase in the number of vibrations shortens the wave length and increases the pitch and that "the vibration frequency of strings of the same material varies inversely as their lengths and the square roots of their weights and directly as the square roots of their tensions."  All of which are important factors to be considered.

    Vibration may be administered in the following forms, irrespective of the type of vibrator -although some vibrators may be found to be more suitable for some modes of application than others.

1. INTERRUPTED VIBRATION is an interrupted vibratory impulse communicated to the body without pressure, or with varying degrees of pressure.

    A. Superficial without pressure.

    B. Deep with light, moderate, or heavy pressure.  Heavy pressure may be compressing in character.

2. STROKING - A superficial vibratory impulse applied with motion over a part, no pressure being exerted.

3. FRICTION - A deep vibratory impulse applied with motion, and varying degrees of pressure over a part.  The subdivisions according to directions are:

    A. Centripetal vibratory friction.

    B. Centrifugal vibratory friction.

    C. Circular vibratory friction.

4. ROLLING - A forward and backward movement of a part over underlying structures.  It is a form of kneading.

    THE OPERATING ROOM should be well ventilated and warm (about 750 F.), because the chilling of a patient causes unnecessary discomfort and induces a state of muscular contraction whereas all parts should be relaxed or in a state of repose when being treated.

    THE FURNITURE NECESSARY will depend somewhat on the type of machine used.  In general, a long, hard table, the height of an operating table, which can be elevated at either end is desirable.  Two adjustable arm rests are a convenience for treating the arms if the operator has no assistant, as the best work can only be accomplished when all parts are in a state of relaxation, and are properly supported.  Two hard pillows of different sizes will be of service.  The table should not be so wide that the operator cannot easily reach across, because some machines cannot be conveniently operated from either side.  If provided with rollers it can be readily moved about by the operator which is often an advantage.  A hard-cushioned Morris chair is also useful in some cases, supporting the body in a relaxed and comfortable position when it is not necessary to have more than a moderate resisting surface as when treating the eye, ear or nose.  A stool is useful when applying special vibration with the patient sitting.  The furniture essential for use with an oscillator is mentioned in the chapter describing its therapeutic application.

    Thoroughly examine each patient before treatment for obvious reasons.  Prolonged mechanical vibratory treatment over a site is best given on the bare surface.  If the patient is a woman and she is to lie down for treatment, she should remove waist, corsets, and all other clothing about the upper part of the body except her undervest, which, in certain cases, as when vibratory friction is applied to the arm, should have short, loose sleeves.  In some cases it is preferable to make the application to the bare skin.  It is always best to cover parts not being treated.  If the upper part of the body is to be treated, let the patient wear a kimona, which can easily be pushed aside as indications require.  All waistbands of the underwear should be loosened, so as not to interfere with circulatory activity and to permit the tissues to be generally relaxed.

    If a man is to be treated he should remove coat, vest, suspenders, collar and outer shirt, and all cases whatever other clothing necessary so that the vibration may not be interfered with. Interrupted vibration may be administered directly over an intervening medium unless prolonged, but mechanical vibratory stroking, friction, or rolling or prolonged interrupted vibration is best applied to the bare skin.  The work should be done in a most thorough and systematic manner, with due regard to technique; and no part should be left until the treatment is finished, opposite portions of the body being best treated successively, because it is thought by some to "intensify the effect upon the nerve centers."  All treatment should be mild at first, then gradually increased in pressure and speed and finally finished with diminishing motion.  Painful parts should be treated with caution.

    It is sometimes advisable that the patient should rest on the table for a short time after treatment and then arise slowly in order to maintain a state of absolute repose and composure so as to avoid the disturbing factors which follow sudden change from a horizontal to an upright position.  It should not be inferred that vibration cannot be applied without the removal of corsets and other garments, but it is best to follow the suggestions given to obtain the best results from mechanical vibratory treatment.

    THE PATIENT'S POSTURE during the treatment should depend upon the indications of the individual case.  The elevation of the head should be regulated by the end sought and the comfort of the patient.  In cases of oedema of the neck the lowering of the head induces a violent headache, therefore elevate the neck and shoulders with a hard pillow or pad, and if the patient is lying face downward, allow the arms to rest in a half flexed or otherwise suitable position on the arm rests if such are provided on the table.  In case the operator has no assistant and is giving a treatment to an arm or leg he may use hard-cushioned pads which serve to elevate the arms or feet as desired.  An extremity is best treated when it is elevated, the patient allowing it to rest in a relaxed state.  During a spinal treatment the patient should lie in the prone position, arms loosely hanging over the sides of the table, unless contra-indications exist, in order to secure relaxation of certain muscles of the back.  Spinal treatments of the cervical and upper dorsal regions can sometimes be more easily administered with the patient sitting.

    JOINTS ARE BEST TREATED in a position midway between flexion and extension.  If the patient lies on his back, his arms may rest extended upwards on the arm rest, if one is provided on the table, toward his head, unless contra-indicated, otherwise the operator should support the joint with his left hand.

    WHEN TREATING THE CHEST place a hard pillow beneath the thorax to elevate it and throw the ribs outward.

    FOR INTERNAL RECTAL TREATMENT the patient should lie on the right or left side, preferably the right, with the knees drawn up, his back being towards the machine.  The knee chest position is preferred when high enemas are given with mechanical vibration.  Other positions will be considered in connection with the treatment of various conditions when taken up in subsequent chapters.  In all cases the position of the patient should always be such that the part treated will be relaxed and the patient comfortable.  The posture should be such that the vibratode can be easily applied, thereby assisting in securing the end desired.

    THE FIRST TREATMENT should be short in order to accommodate gradually the tissues and the patient.  Although there are many who advocate treatment upon alternate days, it is better practice, the author believes, in most cases to follow the rule applied to static methods by Dr. Wm.  Benham Snow in his work on " Static Electricity and the Use of the Roentgen Ray," which is to "bridge the condition of relief from treatment to treatment, lessening the frequency as the requirements permit."  Usually best progress is made when daily treatments are given for four to ten days, and in some cases for longer time.

    Many of the failures leading to such remarks as "Vibration gives temporary relief, but I have seen no cures, and will not give it much consideration until I do" are caused by lack of attention to technique as regards the site of application, duration of application and a non-observance of "bridging" in the management of cases.  No set rule can be made as to methods which will be applicable to all cases, irrespective of cause, condition, effect to be sought or to the frequency of treatments.  Such absurdity can only equal the administration of a particular dose of a drug indicated in a disease irrespective of sex, age, or idiosyncrasy, for a fixed length of time, expecting in all cases to obtain the same result.

    THE INTERVALS OF REST during administration should be as long or twice as long as the treatment of different parts of the body, and the periods of intermission, when interrupted vibration is applied, should be as long or twice as long as the periods of contact unless prolonged interrupted vibration is employed.  A rest of at least half an hour following the treatment will assist the "fixation and perpetuity" of the vibratory effects.

    Vibration should not be administered irrespective of the duration of time elapsing after eating.  It is advisable not to apply it sooner than half an hour after eating and abdominal mechanical vibration is best applied at least after the elapse of one hour.

    THE DAILY ADMINISTRATION should be at a particular time, not in the morning one day and in the evening another.  The duration of each treatment and the frequency of the interruptions during the treatment will also depend on the speed of the machine, stroke, and on the modes of application of interrupted vibration, stroking, friction, or rolling.  It should vary from three minutes to fifteen, or even longer.  For instance, deep or compressing interrupted vibration is relatively short, but stroking, friction and rolling are usually of longer duration.  Sometimes twenty minutes or more will be required to treat a case where varied modes are indicated and results show that such prolonged administrations are not contra-indicated.  The patient's physique and the conditions to be treated should always be considered.  The most careful application with large experience, judgment and close observation will greatly assist the operator in making correct discrimination.

    Too much stress cannot be placed on the three important factors of administration - speed, stroke, and pressure - as employed in mechanical vibration therapy.

    IF A MODERATE RATE OF SPEED be applied with a medium stroke without pressure, and the same rate of speed and same stroke be supplemented by pressure, deeper penetration and diffusion result.  The employment of a given speed and medium stroke without exerted pressure will induce the same depth of penetration as another slower rate of speed and medium stroke with some pressure; and if the speed be much accelerated the penetration without exerted pressure will be relatively increased.

    If a given speed and shortened stroke be employed without exerted pressure, the effect is more superficial than with an increased speed and same stroke with pressure.  In other words, increasing the speed intensifies the effect.  Effects produced by light, moderate, or heavy pressure are modified by the length of stroke, and rate of speed relative to the part to which it is applied; what causes stimulation of one part of the body may induce inhibition in another, other things being equal.

(1) Pressure under all conditions increases penetration and diffusion of vibration.

(2) To increase or lessen speed with a given stroke will increase or lessen penetration and affect the quality of the vibration, producing fine or coarse vibrations.

(3) An increase or lessening of stroke with a given speed increases or lessens penetration and affects diffusion.

    In the employment of mechanical vibration due regard must be paid to stroke and speed.  As a rule a low rate of speed with a sufficiently long stroke has a sedative effect on pain, and also a high rate of frequency with a medium or short stroke has a benumbing effect.  Directions as to stroke in chapters following should be considered in a relative sense, for the medium stroke of one machine corresponds to a stroke much shorter than the medium of another stroke being an arbitrary factor.

    WHEN APPLYING INTERRUPTED VIBRATION TO THE SPINE, a full stroke with a moderately rapid rate of speed is desirable.  The ball vibratode is used for spinal vibrations.

    IF APPLIED TO THE EYE OR EAR, however, the shortest possible stroke is necessary.  The soft rubber cup shaped vibratode is preferred in these sites.

    FOR ABDOMINAL WORK the rubber covered disc vibratode with a medium or full stroke is generally preferable.

    FOR THE ADMINISTRATION OF FRICTION generally a medium or full stroke is to be preferred, but for vibratory stroking, the shortest stroke is in order.  The rubber covered disc vibratode is used when applying friction, and either the disc or the soft rubber cup shaped vibratode is employed when stroking is indicated.

    THE STROKE, it will be observed, should always be adapted to the part treated and the SPEED to the indications of the case.  For example, the shortest stroke might be applicable with vibration of short duration and moderate speed for anaesthesia, but vibration of long duration with a rapid or high rate of speed should be applied for the relief of spasm of the same part.

    PRESSURE, as applied to vibratory therapy may be designated as light, moderate, or heavy pressure exerted by the hand of the operator when applying the vibratode.  Dr. Thomas Stretch Dowse [Lectures on Massage and Electricity in the Treatment of Disease] says that "pressure is transmitted variably, according to the resisting power of the tissue to which it is
applied - to its vitality - and to its mass.  Pressure of given quantity deranges molecular integrity, alters equilibrium, and so engenders irritability and instability.  Pressure of given intensity produces molecular inertia and death.  According to the nature of the pressure applied and the resisting power of the tissue operated upon, so do we get changes in such tissues of molecular activity and irritability, or molecular derangement and death." Light pressure on the trunk of a nerve acts as a stimulus and is transmitted to the nerve.  Continued deep pressure applied to a nerve induces sedation, as it benumbs and may essentially paralyze the nerve, and probably at the same time lessens the blood supply of the part.

    In the employment of vibration, moderate pressure is recommended to the nerves over points or between the transverse processes on each side of the spine alternately in most cases, but of course many factors should be considered before the operator decides upon the degree of pressure to apply.  Tolerance to pressure increases during an administration, and during the progress of a course of treatment.

    If too great pressure be used nausea, weariness, or pain may result.  Pressure over a nerve trunk should be applied with caution.  Sometimes the pressure should be applied directly over the seat of pain as well as over the seat of its origin, as in neuritis.

    Pressure should be light at first during an administration and gradually increased as the pain lessens to as great a degree as constantly increasing deeper pressure can be borne.  If the case under treatment be a stubborn one, do not attempt to fully relieve all of the pain at one administration.  Be satisfied with a short treatment and its results, or the patient will
be the sufferer.

    A moderate pressure, but firm, is advisable when it is sought to produce spinal stimulation.  The application over the spinal region should be made between the transverse processes, care being taken not to place the vibratode too close to the spine.

    It should be remembered that a heavy pressure, especially when prolonged, produces an inhibitory effect which is exhausting.  For this reason heavy pressure is applied in the form of deep interrupted vibration, as for relief over a painful motor point.  Sudden heavy pressure is valuable in the treatment of some painful conditions, as neuralgia, but it should be administered with care.  Zederbaum has demonstrated that sudden heavy pressure on a nerve decreases its irritability, but if the same pressure is gradually increased, the decrease was slower and not so "marked."  A principle to be remembered was aptly stated when Dr. Geo.  H. Taylor [Massage], the noted pioneer investigator in vibratory work, said, "The degree of force of processes applied must be apportioned to the degree of irritability of the different parts of the body and must be the greatest to the least irritable parts.  Sensitiveness to impression is an approximate measure of irritability."  Luderitz found that motor nerve fibres are paralyzed sooner than sensory by continuous pressure.  These are reasons why we should refuse the patient's request for a longer treatment, as is sometimes the case.

    TECHNIQUE requires attention and careful study, as failure or success so often depend on the method employed in vibratory treatment.  A good apparatus will permit the operator to use it as the trained masseur would use his hand - according to its particular adaptability in all its forms from the lightest touch to the greatest force.

    When a vibratode is applied to the surface of a patient it should not come suddenly in contact, as a blow or shock, but should be at first applied with a light touch or pressure.  A light touch has a soothing effect.  A cold metal vibratode is disagreeable when applied to the bare skin of the patient.  It is desirable therefore that such a vibratode be warmed to about the temperature of the body before it is used.

    ASEPSIS is also important with the promiscuous use of vibratodes.  They should be thoroughly cleansed by boiling or by washing them with alcohol or solutions of carbolic acid or bichloride.

    INTERRUPTED VIBRATION may be defined as an interrupted vibratory impulse communicated to the body without pressure or with varying degrees of pressure.  It may be subdivided into two classes, superficial and deep.  The deep may be compressing in character.

(1) Superficial interrupted vibration may be considered a very short, light interrupted touching of the part with the vibratode.

(2) Deep interrupted vibration, on the other hand, may indicate a very short interrupted application of a vibratode to a part of the body with pressure - light, moderate, or heavy.  Compressing interrupted vibration is a term which indicates very slowly interrupted vibratory compression of a part, exerted with heavy pressure.  Vibration applied with any exerted pressure, light or heavy, penetrates deeply, relative to the stroke, speed, and the structure of the part treated.

    SUPERFICIAL INTERRUPTED VIBRATION is accomplished by lightly touching the part, the periods of rest being as long or twice as long as the time of contact, which should be but for a few seconds.  It imparts a varied light movement, the vibration varying in rate, force, form, and rhythm, according to the speed used, and the relative power of a machine, as some machines, running at a given rate of speed and having a known power, but of a certain type of construction, impart much more force than others using the same power and running at the same rate of speed on account of the particular movement or stroke of the vibratode - to and fro, rotary, up and down, or oscillatory.

    This method of vibration is applicable in the treatment of the eyes when an effect soothing in character is desired, as it acts as a sedative to the nervous systems lessening nervous irritability.  It is desirable, when using superficial interrupted vibrations, that quiet prevail, as the effect thereby is intensified.  This type of vibration can be employed with all machines including an oscillator provided with a hand applicator.  The application can be made with the vibratode held in a sidewise or perpendicular position, the position altering somewhat the form of movement imparted, i. e., a vibratode that gives a to and fro motion in a horizontal plane if held perpendicularly, will give a percussion stroke when held oblique or parallel to the surface plane.

    DEEP INTERRUPTED VIBRATION is administered by applying the vibratode with a light, moderate, or heavy pressure to the surface of the patient for a few seconds, and then removing it.  The applications should always be followed by intervals of rest as long or twice as long as the period of application unless prolonged interrupted vibration is employed.  As a rule, such applications should be made three, four, or five times to a given site and should be moderate or heavy, according to indications.  This form of vibration differs from superficial interrupted vibration in that some pressure is used.  An administration should always be begun with light pressure, gradually increased as pain diminishes.  According to Taylor [Massage], imparted motion "contributes to and participates in chemical activity" and it is necessary that there be a certain degree of motion with pressure in order that motor energy may restore the chemical change which is present in health.  He thought also that physical results were proportional to the different rates of transmitted motion, i. e., a deep interrupted vibration with light pressure, a given speed and stroke being used, gives a different degree of penetration than a moderate pressure with the same speed and stroke.  The same authority believed that there are two periods for waves of motion that have been transmitted one when "fibres, membranes and molecules glide upon each other with some degree of adhesion, promoted by pressure," this period being quite "similar in quality and rate of motion, whether the waves are long or short."  The second period is at the end of the stroke when "the direction of the motion is reversed," when reinforced energy is set free into other forms of energy, principally chemical energy.  One of the principal uses of this phase of vibratory work is stimulation of the spinal nerves through the internal branches of the posterior divisions of spinal nerves, and the sympathetic nerves through the rami communicantes.  If the pressure applied be too great, the patient will complain of pain over the back in some cases for several days after the treatment.  This has led some already to condemn and abandon vibratory treatment.  Treatment should therefore be begun with light pressure, the operator bearing in mind Zederbaum's demonstration that sudden heavy pressure on a nerve decreases its irritability and that the degree of pressure should be governed by the irritability of the several parts, and must be greatest to those which are least irritable.  Jacoby [Journal of Nervous and Mental Diseases, 1885] of New York found that rapidly repeated percussion on the nerve of a muscle increased the muscular contractility, but if too long continued, exhausted it.

    DEEP INTERRUPTED VIBRATION IS APPLICABLE to oedema, swelling, pain, and congestion, and is especially useful in the treatment of joint affections.  Always bear in mind that light pressure stimulates, and heavy pressure exhausts.

    BY COMPRESSING INTERRUPTED VIBRATION is designated firm pressure applied to a part interruptedly.  Contacts with such interruptions should in most instances be made for a number of times less than when using short interrupted vibration.  It is particularly indicated for application to "motor points" and for spinal vibrations, and at painful sites for the purpose of benumbing the nerves and lessening the blood supply.  Hyperaesthesia is also favorably affected by its employment.  In the treatment of hyperaesthetic cases vibration of long duration is indicated.

    When applying compressing interrupted vibration to the abdomen, during each forced expiration carry the vibratode more and more deeply and allow for short intervals of rest, few in number.

    By VIBRATORY STROKING is designated lightly touching a part of the body with a vibratode and at the same time moving it over the surface in indicated directions.

    When about to apply vibratory stroking the operator should test the speed, rate, and stroke by placing the vibratode on the side of his own cheek or forehead and lightly stroking the parts.  When it produces a soothing, agreeable sensation the conditions will be right for making an administration.  The stroke should be as short as possible, the speed fairly rapid, but not so rapid as to produce stimulation.  For this form of administration a soft rubber vibratode, particularly the rubber covered disc or soft rubber cup shaped vibratode is preferable.  The writer has applied it very successfully in the treatment of headache, and has noted that in this condition the stroke should be made rather slowly and with a very careful touch.  It may be applied many times over the same place, the effects sought determining the duration.  The touch should be very light in order that a sense of friction is not produced a soothing effect being desired.  It may also be applied for reflex effects to areas of the skin, stimulation of which, by massage, was first advocated by Kellogg for the purpose of reflexly stimulating the spinal centers with the object of affecting not only the muscles, but the internal organs as well, and also to increase secretary, excretory and vascular activity.

    According to Starr the segmental localization of muscular reflex acts is as follows:

Segment              Reflex Act (*Starr.  Organic Nervous Diseases, page 180).

4C to 1D             Pupillary reflex.  Pupil dilates when neck irritated.
5C to 1D             Scapular reflex. Contraction of scapular muscles when skin over scapula is irritated.
5C to 6C             Biceps and supinator longus. Flexion of the forearm when their tendons are tapped.
6C                       Triceps reflex. Extension of forearm when tendon tapped.
7C                       Scapulohumeral reflex. Adduction of arm when inner lower edge of scapula tapped.
6C to 8C             Extension of hand when extensor tendons at wrist tapped.
7C to 8C             Flexion of hand when flexor tendons at wrist tapped.
8C to 1D             Palmer reflex.   Finger clonus caused by stroking palm.
9D to 12D           Abdominal reflex.  Retraction when side of abdomen stroked.
1L to 3L              Genital reflex.  Contraction of abdominal muscles when testicle squeezed.
2L and 3L            Patella tendon.  Knee-jerk when tendon at knee struck.
1S to 3S               Foot clonus.  Flexion of ankle due to extension of Achilles tendon.
1S to 3S               Plantar reflex.   Flexion of toes or extension of great toe and flexion of others when sole of foot tickled.

    Kellogg [Art of Massage] also adds the thoracic at the sides of the thorax "between the fourth and fifth ribs."

    It must be remembered when the chain, consisting of the centripetal nerve carrying the message, the anterior horn of the spinal cord and the motor nerve is broken, the reflexes are accordingly affected, being absent or lessened in degree.  The stimulus to produce a reflex action must be stronger than one required for stimulation of the motor nerve directly, and the stimulation of "the specific end-organ of the afferent nerve" produces more easily a more complex reflex movement than stimulation of its trunk [Hall: Landois and Stirling. Text-Book of Human Physiology, 4th edition, page 809].

    PLANTAR STROKING is indicated in cases characterized by loss of tone of the legs; cremasteric and gluteal stroking in rectal or vesical atony; abdominal stroking for relaxed walls of constipation, and lack of tone; and interscapular stroking in certain cases of anemia.  In general, vibratory stroking is used where there is a lack of muscular tone in the area, to which stimulation of the reflexes induces contraction and increases the tone.

    VIBRATORY STROKING can be most effectively applied in respect to direction by observing the rules of stroking as used for massage which are as follows:

    "Head - from before backward, starting at the center of the forehead and from above downward, starting at the vertex.

    Back - from above downward, from the median line outward.

    Chest - from the sides toward the median line.

    Abdomen - upper part, from the sides inward and upward; middle part, toward the median line; lower part, from below upward and inward.

    Arms - from the shoulders toward the hands.

    Legs - from the hips downward.

    Feet - from the toes toward the heel."

    Stroking is generally directed against the venous flow, but may be applied in any direction indicated in the case.

    VIBRATORY FRICTION applied with moderate pressure is of more value than is generally recognized.  It is applied by moving the vibratode over a part of the body with varying degrees of pressure suited to the particular part or condition under treatment.  Winternitz demonstrated that friction by hand power increased the excretion of moisture 60 percent., and dissipated heat more than 95 per cent. and in some cases increased heat elimination 95 per cent.

    WHEN APPLYING VIBRATORY FRICTION the vibratode should be moved rapidly over the surface, and since superficial effects only are sought, such as its effects on the circulatory system and lymphatics, a light, or between a light and a moderate pressure, will be required.  A fairly short stroke (one suited to the part treated) and a fairly rapid rate of speed are also essential features of this method of application.  If the skin is delicate or moist a little talcum powder dusted over the surface to be treated before applying the vibratory friction will assist in diminishing the friction irritation, but it is seldom necessary.  A rubber covered disc vibratode is preferable for the administration of this method.

    VIBRATORY FRICTION MAY BE APPLIED TO MEET DIFFERENT INDICATIONS, centripetally, toward the heart, centrifugally, away from the heart, and in a circular direction.  If the direction be centripetal, follow the course of the large veins particularly, i. e., the course of the median on the median line of the anterior surface of the forearm, and the ulnar along the inner border of the forearms both anteriorly and posteriorly, the basilic on the inner and the cephalic on the outer side of the arms.

    CENTRIPETAL VIBRATORY FRICTION increases the flow of lymph, blood and chyle, and assists absorption, whereas CENTRIFUGAL VIBRATORY FRICTION tends to lessen such activity, and is used to produce soothing and derivative effects on organs, as relieving oedema.  If the chest be treated, let the direction be from the sternum on either side toward the axillary space; and in case of the abdomen from the median line down and out, and in some cases circular, the umbilicus being taken as the center.  Vibratory friction centripetally over the parts between the affected portion and the heart is indicated in swelling, dropsy, gout, rheumatism, sprains, sciatica, etc.  If the inflammation be local, vibra-massage should be applied particularly between the site and the heart.

    Headache may sometimes be relieved by the application of vibratory friction of the spine, thus affecting the vaso-motors.  Pelvic pain may often be relieved by applying vibratory friction over the lumbar and sacral regions.

    CENTRIPETAL VIBRATORY FRICTION may be applied to the head from the median line backward, downward, and outward to the line of the middle, or inferior cervical region.  When applying it to the neck anteriorly follow the line of the vessels from above downward.  When applying it to the hand and the arm for producing other than the lightest superficial penetration, a little less than medium stroke is to be preferred with moderate pressure, and a medium rate of speed.  The patient should lie upon the table, at first face downward, resting his hand and arm on the arm-rest, or lightly on the palmar surface of an assistant's hand, while with the other the assistant should support the patient's elbow, the hand being held higher than the elbow.  Treatment should be given with the patient's arm perfectly relaxed, else the muscular tension will oppose the effect sought.  Apply the vibratode five or six times, beginning at the finger tips, particularly in the intermetacarpal spaces and extending it to the wrist.  To the wrist, in most cases, also apply deep interrupted vibration with moderate pressure in the usual manner, the operator supporting the wrist with his left hand.  Then, with the patient lying on his back with the arm supported on an arm-rest or an assistant holding the hand elevated as before, make the application to the palmar surface of the hand and arm, applying deep interrupted vibration with moderate pressure in the palm, and about the wrist for the purpose of reflexly inducing greater circulatory activity.  The fore-arm should be treated from the wrist to the elbow, posteriorly and anteriorly, the vibratode being moved rapidly over the surface following the course of the ulnar, the median and the radial veins.  Then apply deep interrupted vibration to the elbow joint it being supported by the operator's left hand.  This should be followed by vibratory friction of the arm from the elbow to the shoulder, and interrupted vibratory treatment of the axillary glands.  The treatment is usually not continued longer than for seven or eight minutes to an arm.  In applying it to the lower extremities proceed from the toes to the heel, then from the toes to the ankle, using deep interrupted vibration with moderate or heavy pressure, according to the thickness of the foot, under the arch of the foot and about the ankle.  In applying it to the leg, the patient should lie face downward with leg flexed on the thigh and supported by an assistant.  Apply then vibratory friction posteriorly, first from the ankle to the popliteal space four or five times, moving over the surface following the course of the veins; then anteriorly.  Then use interrupted vibration at the knee joint two or three times in the depressions about the joint.  The thigh should be given a vibratory frictional treatment posteriorly and anteriorly, then apply deep interrupted vibration to the groin.  When used to lessen oedema of the arm, apply deep interrupted vibration to the axillary glands, then vibratory friction from the elbow toward the axilla.  Deep interrupted vibration of the elbow joint should follow.  Vibratory friction centripetally should then be applied to the forearm, followed by deep interrupted vibration to the wrist joint.  The hand should then be treated with vibratory friction.  A similar plan should be followed for oedema of the legs and thigh.

    VIBRATORY FRICTION TO THE NECK should be applied from the space between the angle of the jaw and the mastoid process downward and inward to the lower border of the neck, and then outward to the shoulders after which apply extremely superficial interrupted vibration on each side of the larynx.  Posteriorly employ vibratory friction from the occipital protuberance over the neck downward and outward.  It is desirable to have the patient lie face downward at first and then on her back and allow a few minutes' interval of rest between these applications.  A medium stroke is preferred.

    When applying VIBRATORY FRICTION TO THE CHEST the patient should lie with the arms upon the arm rests of the table the inclination of which will depend upon indications.  Apply the vibratode from the insertion of the pectorals toward the sternum three or four times and then below the pectoral muscles, vibrating from the sternum out and around to the axilla following the course of the ribs.

    VIBRATORY FRICTION IN THE CTRC-ULAR AND CENTRIPETAL DIRECTIONS should be applied with fairly deep pressure when application is made to the hip.  Circular friction is first employed and then centripetal, forward along the iliac muscle from the great trochanter.

    When applied to the back begin at the occiput and follow each side of the spinal column to the pelvis, then apply friction from above downward, the vibratory circular friction to be employed with moderate pressure above the scapulae.  Below the scapulae follow the ribs from without inward toward the spine.  Then use deep interrupted vibration with moderate pressure from above downward alternately on each side of the spinal column making the applications between the transverse processes three or four times to each site.  Care must be exercised that the pressure is not too heavily applied lest pain and tenderness follow.  As demonstrated by Professor Maggiora the duration of an application is an important consideration requiring an exercise of care lest it be too long.  Vibratory friction is applicable to inflammatory conditions and oedemas. In such cases begin the friction at the part nearest the trunk and gradually approach the distal part affected always working toward the trunk.

    THE APPLICATION OF FRICTION is best based upon methods in use for years by scientific masseurs.

"(1) Head - from before backward and above downward.

(2) Neck - downward.

(3) Back - above shoulder blades circular; from shoulder blades to sacrum down; in the region of the loins, from the sides toward the spine.

(4) Hips - circular.

(5) Chest - from the sternum toward the axilla.

(6) Abdomen - upper part, from above downward, and outward; lower part, from the median line downward and outward.

(7) Arms and legs - from below upward."

    In cases of oedema of the arms vibrate the axilla then start at the inside of arm and proceed up, at the same time gradually approaching the hand.  Apply interrupted vibration at each joint as it is reached.

"(8) Hands - from the finger tips to the wrist, dorsum first.

(9) Feet - from toes to the heel on dorsum first then from toes to the heel and instep alternately."

    In oedema of legs apply interrupted vibration to the inguinal glands.  Then commence at inner side of thigh and proceed up, at the same time gradually approaching the foot.  Apply interrupted vibration to each joint as it is reached.

"(10) Face - from the median line of the forehead outward to the temples, then downward toward the chin."

    FOR GENERAL VIBRATORY TREATMENT the patient should be clad in a loose robe and all parts except that to be treated should be covered.  The order preferred is that used in general massage, - "(1) Arms, (2) chest, (3) legs, (4) abdomen, (5) hips, (6) back, (7) head, (8) neck." General treatment is very rarely indicated and when used should be exceedingly short, the vibratory frictional treatment being the one best suited for the purpose.

    VIBRATORY ROLLING, the last modality, is applied by using the ball or roller vibratode to roll backward and forward over a part with varying degrees of pressure, moderate particularly, to stimulate functional activity especially of the skin.  If the arm is to be treated roll the parts on the underlying structures to and from the shoulders gradually approaching the elbow and in like manner from the elbow toward the hand.  The stroke should be in accordance with the indications, and the rolling should be rapid but the speed medium.  When manual massage is used centripetal friction followed by the rolling has been found useful.  It favors the production of heat and stimulates cellular activities.

    The above includes forms of application to which modern vibrators of different types of independent motion may be adapted.  A growing demand will eventually bring forth more perfect machines as new features are suggested by skillful clinicians.  It seems probable however that the skill and technique of the hand united with the never tiring power employed with modern appliances under the absolute control and guidance of the skilled operator, is certain to accomplish more easily and with better results the otherwise laborious task of the masseur, the degree of touch as a factor sacrificed in mechanical vibratory work being dependent on the operator's individuality of touch transmission.

    A good rule to follow is that of scientific massage.  "All of the single or combined procedures should be begun moderately, gradually increased in force and frequency to the fullest extent desirable, and should end gradually as begun.  "Vibration can be used to advantage oftentimes in connection with electricity, hydrotherapy, phototherapy, and exercise, passive or active, assistive or resistive.  If the part treated be motionless and exercise is indicated, prescribe passive motion.  If there be slight but not complete motion use assistive movements, if a superfluity of motion resistive movements are indicated, but care must be taken not to strain the part.  The motions should be slowly and regularly executed, and each movement should be followed by a short interval of rest.  It is also necessary that the exercises be taken daily.  When dizziness, palpitation of the heart, pain in the chest, very rapid breathing or any other difficulty follows the exercises, they should be modified, possibly changed, or even omitted for a time until the powers of the patient warrant a continuance.  There should always be an interval between the time of exercise and the meal preceding as well as the meal following.