Light therapeutics; a practical manual of phototherapy for the student and the practitioner, with special reference to the incandescent electric-light bath

Front matter

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Preface

THIS work does not profess to be an exhaustive treatise on the subject of light therapy. It is intended rather to serve as a practical manual for the clinical use of the electric-light bath in its various forms, and in its various applications, general and local.

An effort has also been made, in a small way, to correlate the electric-light bath to those other forms of rational physiotherapy which naturally and profitably associate themselves with this newest of physical curative measures.

Twenty years ago this work could not have been written. The electric bath had not yet been devised. The photophore, the electric thermophore and most of the other therapeutic methods and appliances described in this manual were not even dreamed of. Probably no non-medicinal remedy has ever found its way so rapidly into general favor as have devices for utilizing the physical properties of light in combating the inroads of disease.

The first incandescent light bath was constructed by the author in 1891. After it had been used in the treatment of some thousands of patients at the Battle Creek Sanitarium, a bath was exhibited at the Chicago Exposition in 1893. A visitor from Germany saw the bath, visited Battle Creek to become familiar with the technique of its use, and on returning to Germany began its manufacture and sale in that country. German medi-

4 PREFACE

cal men and financiers soon recognized the value of the method. Winternitz of Vienna constructed a bath after the author's description, which was first published in a paper delivered by request before the American Electro- Therapeutic Association at its fourth annual meeting, New York, Sept. 25, 1894.

The bath soon became highly popular in Germany. Hundreds of Light Institutes were opened in the leading cities. King Edward of England was cured of a distressing gout at Hamburg by means of a series of light baths. He had the bath installed at Windsor and Buckingham palaces. Emperor William soon after followed his example, as did several other of the crowned heads and titled families of Europe.

In time the fame of the bath spread back to its home. A New York firm actually imported a bath from Berlin as a therapeutic novelty. The last few years have witnessed a growing interest in phototherapy and the time will soon arrive when no hospital will be considered completely equipped which does not include in its outfit a full set of electric light appliances for therapeutic use.

Trusting that this volume, incomplete and imperfect as it is, may prove of practical use to some of those who have recognized the value of this new method in the clinical management of many forms of chronic disease, the author submits this little work to his colleagues in the profession, craving their consideration and criticism.

J. H. K.

Battle Creek, Mich.

Contents

PAGE

I. The Physics of Light 9

II. The Physiologic Effects of Light . . 17

II. The Physiologic Effects of Light

ALTHOUGH the influence of light upon animal and vegetable life has long been known in a general way, it is only within a comparatively short time that the subject has been studied with sufficient care to place the therapeutic utilization of light upon a sound and rational basis. The experiments of Arloing, d'Arsonval, Geisler, Paul Bert, DuBois, Graber, and especially Finsen, have contributed most important facts toward the solution of the many interesting questions connected with this subject.

When closely analyzed, these effects may be shown to belong to two classes: first, those which are due to the action of the chemical rays ; and second, those which are due to the heat radiations. Practically, these effects are always more or less combined, but for clearness it is well to consider separately the two classes of effects.

EFFECTS OF THE CHEMICAL OR ACTINIC RAYS

The experiments made by Finsen and others show that chemical and thermic rays exert a decidedly different influence upon plant growth. The ultra-violet rays increase flowering, while the heat rays enhance the aroma. The action of the sunflower and other heliotropic plants in bending toward the sun shows the powerful influence of light upon life processes as manifested in plants. Plants, however, appear to be subject to damage from

2 17 excess of the chemical rays just as animals suffer sunstroke from excessive exposure to the sun.

Grraher observed that the earthworm, which habitually lives in the dark, when placed in a box half of which was covered with a red glass and the other half with a violet glass, at once placed itself under the protection of the red glass, toward which it behaved the same as toward total darkness. Although we are ordinarily unconscious of the fact, there is no doubt that our life processes are influenced — to a degree far greater than we are able to appreciate or comprehend — by these subtle emanations from the sun which are known as the chemical rays. We may, indeed, be influenced by still more subtle emanations from those far-away suns which we call the fixed stars ; so there may have been something more than poetry in the question of the ancient sage, "Canst thou bind the sweet influences of the Pleiades?"

A VITAL STIMULANT

The classic experiments of Finsen, some of which the writer had the opportunity to witness, having twice visited the Light Institute at Copenhagen to see the work of this ingenious investigator and become acquainted with his methods, clearly demonstrated that the actinic rays are a powerful excitant of vital activity, and hence promote to the highest degree all the processes of animal life and energy. This was a discovery of the highest importance — one which explains many facts of common observation which have heretofore been inexplicable.

The chemical ray is the source of the energy which enables the plant to elaborate in its leaves, under the influeiice of the sunlight, the various products necessary for its development. Vegetahle structures consist, in fact, of simple elements held together in complex molecules by the chemical energy of the sunlight. Under the magic influence of these miracle-working rays, the elements found in earth, air and water are organized into groups, some comprising thousands of individual atoms, the breaking up of which, as the result of vital activity, liberates the light energy employed in holding together these organic unities, permitting the energy thus set free to manifest itself in muscular and mental efforts, and various other forms of vital work.

To be able to harness this force, to control it, and to focus it upon any desired organ or function of the body, is one of the newest and greatest triumphs of modern therapeutics.

THE EFFECTS OF LIGHT UPON PLANT LIFE

Siemens in 1880 published a detailed account of experiments for the purpose of determining the influence of light upon vegetation. The following may be deduced from his results : —

1. The electric light is efficacious in producing chlorophyl in the leaves of plants, and in promoting growth.

2. An electric center of light, equal to 1,400 candles, placed at a distance of two meters from growing plants, appeared to be equal in effect to average daylight at this season of the year (March) ; but more economical effects can be attained by more powerful light centers.

3. Carbonic acid and nitrogenous compounds generated in diminutive quantities in the electric arc produce no sensible deleterious effects upon plants enclosed in the same space.

4. Plants do not appear to require a period of rest during any part of the twenty-four hours of the day, but make increased and vigorous progress if subjected during the daytime to sunlight and during the night to the arc light, showing that it is a substitute for sunlight, or identical with it.

5. The radiation of heat from powerful electric arcs can be made available to counteract the effect of night frosts, and is likely to promote the setting and ripening of fruit in the open air.

6. While under the influence of electric light, plants can sustain increased stove heat without collapsing, a circumstance favorable to forcing by electric light.

In plants, chlorophyl pigment can only be formed in the light. Plants and plant parts grown in the dark have no chlorophyl, but are pale yellow in color. The yellow rays are needed for chlorophyl (Freund). The quantity of light need not be large. A light barely strong enough for the reading of large print enables sprouting plants to grow dark green (Wiesner). Plants grown in the dark have abnormally long internodes and leaf stems, but no leaf surface.

Experiments by Herve-Mangon demonstrated that the arc light is capable of causing a development of chlorophyl and of inducing heliotropism (bending toward the source of light). Prillieux showed that the arc light is capable of promoting assimilation in plants.

THE EFFECTS OF LIGHT UPON ANIMAL LIFE

The development of many animals is dependent upon light. Frog spawn die in an opaque flask, while in a transparent glass vessel they develop normally. Tadpoles develop more slowly in the dark than in the light (Edwards).

Auerbach observed that the protoplasm of frogs contracts under the influence of light. The white cells of frog's blood showed more and longer processes in red than in violet light. In red light they were spread out in the form of thin, hardly visible disks (Uskoff).

Finsen observed that the red corpuscles in tadpoles were contracted and became rounder under the influence of light.

Finsen also noted that the growth of the nails, hair and other epidermal tissues is encouraged by light and hindered by darkness. In his clinic he has noted that patients and nurses who work for a long time with powerful arc lights grow more hair on the arms which are much exposed to the action of light.

According to Harrington and Learning, red light (short-length heat waves) is most favorable to the movements of the amceba, both the violet and the yellow rays impeding its movements. Englemanu observed contraction of the amceba on sudden exposure to light, and rapid relaxation of the amceba when suddenly exposed to darkness.

Loeb found that the more refrangible rays encourage the growth of polypi. The red rays have the same effect as total darkness.

Flies' eggs develop more rapidly under glass admitting only the chemical rays than under glass admitting luminous or heat rays (Beclard). Maggots develop more quickly in pieces of meat exposed to the light than in meat kept in the dark (Gadneff).

The activity of the silkworm is encouraged by violet light (Guarinoni).

Light without heat causes the iris to contract in the eye of amphibia and fishes. This happens in any case, even when the retina has been removed and when the eye has been extracted a long time before (Brown-Sequard). This phenomenon is probably due to direct irritation of the muscle by light. Harless, in studying human corpses thirty hours after death, observed distinct contraction of the pupil of the eye when exposed to light. Engelmann also showed that light causes the rods and cones of the retina to shorten, while darkness lengthens them.

It is a matter of common knowledge among farmers that domestic animals develop better in well-lighted sheds than in dark ones. The same principle is recognized with reference to the development of young children.

EFFECTS OF THE ACTINIC RAYS ON THE SKIN (SOLAR ERY- THEMA)

Nearly half a century ago Charcot suggested that sunburn, or solar erythema, might be due to the ultra-violet rays. Wilde observed that a so-called sunburn is not a burn at all, since it does not appear at once but comes some hours after exposure. Finsen furnished the scientific proof that a sunburn is simply an erythema resulting from an irritation set up by the ultra-violet rays. This phenomenon, which is quite too familiar to require description, affords most positive evidence of the potency of the chemical rays. Charcot, Widmark, Bowles and others have shown that the dermatitis produced by the electric arc light (light-burn) is also due to the action of the chemical rays.

All persons are not equally sensitive to this influence of the chemical rays. Brunettes suffer less than do blondes. Negroes and other dark-skinned races are largely exempt from this unpleasant effect of the sun's rays. Lower animals as well as human beings are sensitive to the chemical rays, white cows being subject to sunburn the same as white-skinned men, while red and black cows are exempt.

Cows which are spotted red and white, or black and white, are subject to sunburn on the white spots and not on the dark spots. The curious fact has been observed that certain light-colored animals, especially cows or pigs, are more subject to sunburn after feeding on buckwheat. The reason for this has been supposed to be the development in the blood of some peculiar substance derived from the food or developed under the influence of light.

Sunburn may be produced even more easily by the arc light than by sunlight, owing to the greater richness of the arc light in chemical rays. The writer has often seen a very intense erythema induced as the result of an exposure lasting not more than five to eight minutes. Considerably longer time than this is generally required to produce sunburn by exposure to the sun's rays.

Pigmentation of the skin, or tanning, follows repeated or prolonged exposure to the influence of light, either with or without solar erythema. The cause of this darkening of the skin is the increase of pigment material through stimulation of the pigment cells of the skin. Bruecke and others have proved that the pigmentation of the skin is due to local action of the actinic rays on the skin, and not to the heat rays. In connection with solar erythema, there is doubtless also a disintegration of blood-cells and the deposit of pigment from this source following sunburn. Sunburn usually occurs but once in persons who are taking a course of light applications, but to this rule there are occasional exceptions. The purpose of this increased pigment in the skin is protection. Even mulattoes have a much darker complexion when exposed to the sun in the summer time than in the winter season. In the South Sea Islands, when the natives are obliged to expose their naked bodies to the sun's rays for some time, they protect themselves from unpleasant effects by smearing their skins with black pigment.

Maklakow found that after a fifteen-second exposure to the powerful arc light the skin did not react at all for ten hours. After a one-minute exposure, circumscribed hyperesthesia was produced after half an hour. After two and three-fourths hours, redness of the skin was apparent. Exposures of three and one-fourth minutes were followed by redness in eleven minutes. Exposures for five and three-fourths minutes were followed by erythema in three minutes. Finsen and Moeller, after carefully investigating these results experimentally, confirmed them. It has been proved that the greater the light intensity, the sooner the appearance of the reaction and the longer its duration.

PENETRATING POWER OF DIFFERENT RAYS

Although the less refrangible red rays (short-heat waves) have by far the greatest penetrating power, the numerous experiments which have been made by Gadneff, Finsen, and others, prove that even a - considerable portion of the ultra-violet rays pierce the epidermis and reach the lower layers of the skin. These penetrating rays correspond to the third part of the ultra-violet portion of the spectrum.

Lenkei found that the blue and yellow rays penetrate the skin and living tissues to the depth of one or two centimeters (two-fifths to four-fifths inch). When there was an absence of muscular tissue some of the blue rays penetrated to a depth of over three centimeters (one and one-fifth inches). A small portion of light penetrated as far as five or six centimeters (two to two and two-fifths inches), even through the muscular layer, but this was exclusively the yellow rays. The red rays were not examined, but Lenkei believes that they have a greater penetrating power than the yellow rays. He found that five per cent of the light consists of blue rays, and eighty per cent of yellow and green rays.

Schamberg, of Philadelphia, found that an ordinary 16-candle power incandescent light with a reflector, although comparatively poor in actinic rays, will produce enough light to pass through the skin, subcutaneous tissue, muscles and mucous membrane, and affect a photographic plate in the mouth in thirty seconds, while in another test a light very rich in chemical rays (a mercury vapor light) was not able to produce any effect in five minutes.

Musck found that red, orange and yellow rays passed through his hand and affected a photographic plate in five seconds, while the blue, violet and ultra-violet rays from the same source produced no effect in ten minutes.

HISTOLOGICAL CHANGES INDUCED IN THE SKIN BY LIGHT RAYS ... (J J

The histological changes occurring in the normal skin under the influence of light have been studied by Meirowsky, Schmidt and Marcuse, Schiff, Zieler, Stelwagon, Sack, MacLeod, Moller, Unna and others, who agree in general on the following findings : —

1. Pronounced dilatation of the superficial and deep cutaneous blood-vessels.

2. Migration of the leucocytes.

3. Increase in the number of active tissue cells.

4. Swelling of the collagen.

6. Hyperplasia of the epidermis and abnormal cornification.

7. Swelling of the prickle cells of the epidermis, due to parenchymatous edema. This swelling is caused by the actinic rays. When the skin is examined microscopically there seem to be small vesicles here and there, due to dilatation of the lymph spaces (MacLeod, Glebowsky).

Meirowsky states that under the stimulus of light, nuclear division of the epithelial cells takes place. Unna claims that light makes the skin dense and harder, the protoplasm being reduced to keratin.

Glebowsky made a histological study of the process of healing in cases of lupus under the influence of light treatment. Twenty-four hours after exposure to light, sections of the skin showed dilatation of the vessels and infiltration of the surrounding parts, with active leucocytes. The tissue spaces were dilated. Small vacuoles were clearly marked in the giant cells. These appearances increased as the number of exposures increased. The giant cells were destroyed entirely on an average after four to five exposures. The degenerative processes in the epithelioid elements were less marked as compared with those in the granulomatous cells where observations show most conclusively the value of light in assisting the tissues in the battle against invading parasites.

EFFECTS OF LIGHT UPON THE BLOOD-VESSELS

Sack has shown that the blood-vessels are the first parts affected by the light. The endothelium lining their walls swells and grows rapidly and the process ends in endarteritis, which finally obliterates the vessels. These changes are produced only when the actinic rays are applied in a greatly concentrated form and for a long period.

THE INFLUENCE OF LIGHT UPON THE CUTANEOUS CIRCU- LATION

Those portions of the skin which are habitually exposed to light have a much more active circulation than those parts of the skin which are covered. They are also better prepared to protect themselves against changes of temperature and show a higher degree of resistance generally. The color of skin surfaces which are habitually exposed to light is not only darker but ruddier because of the increased circulation of blood through the part. Blood-vessels of such parts are more widely dilated and more numerous than in parts protected from the action of light. When an exposure to. light is of such a character as to produce erythema, the most intense cutaneous congestion results, such as might be induced by the application of a mustard fomentation or by chemical, thermal or mechanical irritants of other sorts. The congestion produced by the chemical ray differs, however, from that induced by a fomentation in that it is remarkably lasting. One observer reports, as the result of experiments upon himself, that the increased vascularity resulting from a solar erythema was still noticeable six months later. This property of the chemical ray is of great value in therapeutics, as it affords a most admirable method of producing derivative effects whereby a state of collateral anemia may be induced in deep-lying parts. It is often in the highest degree important that such effects be secured as the only means of affording definite relief in cases of visceral congestion of various sorts, particularly in such disorders as chronic bronchitis, gastritis, hepatic congestion, intestinal catarrh, ovarian and other pelvic congestions, congestion of the spinal cord, etc. The writer has for years made use of various phototherapeutic appliances for securing these effects and with most excellent results, and believes that he was the first to point out and apply this use of solar and electric light.

THE INFLUENCE OF LIGHT UPON THE NERVOUS SYSTEM

Very strong light often produces giddiness, headache, and sometimes nausea, as the result of overstimulation of the optic nerve, doubtless through reflex action. Exposure of the head to the direct rays of the sun, and sometimes even exposure of the general skin surface, produces the same and often even more intense effects. Sunstroke affords an illustration of the powerful influence of the chemical rays upon the nervous system, the evil effects of the sun's rays manifested in this condition being due not to heat but rather to the chemical elements of the sun's rays. When traveling in Egypt, the writer often observed natives plodding along the road in the middle of the day with their bodies almost entirely nude, but with a large shawl or scarf coiled about their heads in a huge mass for protection against the intense action of the sunlight. The black wooly hair of the negro and his thick scalp and skull afford the best possible protection against the pernicious influence of the sun's rays upon the brain. Biology teaches us that the eye is simply a modification of the skin. The optic nerve is especially subject to the luminous rays of light, while the cutaneous nerves, certain of them at least, are especially susceptible to the chemical rays. Through the influence of these rays upon the skin, strong excitant or tonic impressions are being constantly made upon the central nervous system, modifying all the nutritive processes and aiding in the maintenance of efficient activity in every vital organ.

THE INFLUENCE OF LIGHT UPON THE CUTANEOUS GLANDS

Exposure to intense light rays causes profuse perspiration. It is not necessary that the atmosphere in contact with the body should be of a high temperature; in fact, the temperature of the air about the body may be considerably below the normal body temperature. The stimulation of the perspiratory glands by the light rays excites their activity to a remarkable degree. The writer observed this in his early experiments with the electric-light bath in 1891, and later in 1894 reported a series of experiments which showed that the amount of perspiration produced in the electric-light bath as compared with that produced in the Turkish bath was nearly double, while the time which elapsed before the appearance of perspiration was very much less in the light bath than in the Turkish bath. Professor Winternitz, of Vienna, mentioned to the writer in 1899 an observation of considerable interest in this connection. In the use of the writer's electric-light bath, which he had installed both in the Polyclinic connected with the medical department of the university and in his great medical establishment at Kaltenleutgeben, he constantly observed that perspiration began sooner on the outer portions of the thighs which were more directly exposed to the influence of the light rays than upon the inner surfaces. He also observed active perspiration in an atmosphere at a temperature much below that of the body, and in one case at a temperature as low as 65° F., in a neurasthenic patient who was particularly susceptible to the stimulus of radiant energy. A much higher temperature than this is required in the vapor bath, the hot-air bath or the Turkish bath, showing that the effect produced must be due to the stimulation of the sweat glands by the light rays.

THE INFLUENCE OF LIGHT UPON GENERAL METABOLISM

The following is quoted from the writer's chapter on Heliotherapy, in volume ix of Cohen's System of Physiologic Therapeutics : —

"An animal eliminates more carbon dioxid under the influence of light than when confined in the dark. This has been found to be true of hibernating animals also. Starving animals lose less weight at night than during an equal number of hours of daylight, although kept equally quiet. Certain animals, as crabs, when painted with dark varnish, are quickly killed, although unaffected by transparent varnish (Heile).

"Eggs develop more rapidly when exposed to the influence of sunlight than when kept in the dark. This is also true of the larvsB of insects.

"Metabolism is unquestionably stimulated by the reflex action set up by the light rays impinging upon the nerve-endings of the skin and retina. Oxidation of living tissues is increased by the action of sunlight (Quincke), while in human beings, as well as in animals, less carbondioxid is eliminated at night than during the same number of hours of daylight, even though an equal degree of quiet be observed (Pettenkofer and Voit). Country children, who are more exposed to sunshine than those in the city, are much healthier in appearance and less subject to rickets, tuberculosis and other grave disorders. Cretinism is most frequently found in deep valleys from which the direct rays of the sun are largely excluded. Eskimo women suffer from amenorrhea during the long polar night."

THE INFLUENCE OF LIGHT ON THE BLOOD

Light increases the hemoglobin of the red cells. Hemoglobin absorbs light to a considerable degree and in a peculiar manner, as shown by the characteristic absorption bands of the spectrum.

Hertel claims that the chemical rays cause a splitting off of oxygen from the plasma of the blood and tissues much in the same way as oxygen is set free from plants under the influence of light. He believes that this process affects both animal tissues and bacteria. Quincke demonstrated that under the influence of light the hemoglobin gives off its oxygen more quickly than in the dark. He regards this as a proof that light increases the oxidizing power of the blood, and that thereby the process of oxidation in the human body may be encouraged.

Grraffenberger claims to have proved that the hemoglobin content of the red cells is diminished in the absence of light, and that prolonged darkness causes a lessening of the total quantity of the blood. Marti showed that in rats absence of light diminishes the number of red cells and the amount of hemoglobin. Strong continuous light accelerates the formation of red blood cells and also the amount of the hemoglobin content. Although Borrisow was not able to confirm this observation, he found in his experiments that dogs kept in the light, after a brief decline, gained in weight considerably, and that appetite was increased, while dogs left in darkness showed no gain in weight. According to Preund the oxyhemoglobin bands in persons examined at the close of the polar night showed signs of extension.

Finsen enveloped the body of a tadpole in moistened filter paper, and after attaching it in proper position to the stage of a microscope, exposed it to the rays of the sun. During the exposure the microscopic examination showed dilatation of the capillaries, slowing of the bloodstream and migration of the white cells, phenomena which are usually observed in simple inflammation. The red cells contracted. Uskoff found that the white cells of frog's blood showed more and longer processes in red than in violet light. In red light they were spread out in the form of thin, hardly visible discs. Hermann claims that the leucocytes are not sensitive to light, but that the red cells usually change their shape.

Axmann found that venous blood after long exposure to the air turns a bright red when exposed to the ultra-violet rays. He believes this effect is due to the nascent ozone. He remarks that fresh and suppurating wounds behaved under the influence of the actinic rays as if they had been swabbed with hydrogen peroxide.

Penetrating luminous heat rays act not only upon the connective tissue, muscular and nerve cells with which they come in contact, but also upon the red and white blood-cells, circulating in the vessels. As these short heat rays are able to penetrate to a depth of two inches or more, it is evident that the blood circulating through the larger arterial and venous trunks is brought under their influence as well as the blood-cells moving through the smaller vessels. Through its rapid movement through the blood-vessels, the entire volume of blood in the body may be thus exposed to the stimulating influence of thermic rays within a comparatively short time. As a result, the functional activities of both the white and the red cells may be greatly stimulated. The oxidation of waste matters will thus be greatly increased, while the destruction of phagocytic bacteria and of debris resulting from accident or by disease will be greatly stimulated. Clinical experience shows that blood production is also increased. This explains the wonderful influence of the sun-bath, recognized from the most aracient times as a powerful stimulant to the vital functions.

Nerve pressure and pain are relieved by exciting the activity of the circulation through congested areas.

34 LIGHT THEKAPEUT1CS

THE ACTION OF LIGHT RAYS UPON BACTERIA

One of the most important applications of phototherapy is based upon the destructive influence of light, or the actinic ray, upon pathogenic bacteria. The deterrent influence of sunlight upon fungi and other plants of low organization has long been known. Many parasitic fungi are easily killed by it. Some bacteria which resist strong solutions of germicides, and even prolonged boiling temperature, are quickly killed by exposure to light. Koch showed that the tubercle bacillus perishes on exposure to the sun's rays, and Kitasato demonstrated that light is destructive to the plague bacillus.