The bronzing or browning of the skin due to a deposit of pigment (melanin granules) around the nuclei of the epidermal and basal cells, following exposure to the rays of the sun, constitutes suntanning. Pigment is the most important protecting mechanism by which the body prevents getting an overdose of sunshine. Melanin, or the pigment that gives color to the skins of man and animals, is absent in albinos and in cases of leucoderma. There is at all times, a certain amount of pigment present in the skins of all normal individuals and this pigment screen is the body's most important protection against too much sun.

Tanning (pigmentation) prevents the over-absorption of ultraviolet rays, and thus, prevents burning. The layer of pigment is the body's barrier against the penetration of an excess of ultra-violet rays, and the more one is tanned, the less is the danger of light rays causing suffering.

Before pigmentation has occurred, an overdose of the chemical rays of the sun, has injurious effects on healthy tissues. Once pigmentation has occurred and a deep brown skin has been obtained, any length of exposure may be endured without discomfort.

Just as chlorophyll is formed as a light screen and filter in plants, so a brown pigment, called melanin, is deposited in the presence of sunlight as granules in the deeper cells of the epidermis. This pigment deposit absorbs the visible and ultra-violet radiations and, after converting them into radiations of less energy and lower vibration, and increased penetrating power, passes them on to the deeper structures.

Melanin prevents the penetration of excesses both of ultra-violet rays and of heat. When melanin powder, obtained from ox-eyes, is mixed with water to form a brown-black suspension, and a few drops of this is placed on the palm of the hand and exposed to light concentrated by a burning-glass, the water will be evaporated without over-heating the hand. Pigmented skin radiates heat more quickly than unpigmented skin; thus a negro's skin exposed to strong sun is cooler than a blonde's skin.

It is customary to divide pigmentation into two types--instantaneous tanning and delayed tanning. The first develops almost immediately after exposure to sunlight; the other develops gradually and continues for several days after exposure to sunlight. The division seems to be unnecessary, as the two types of tanning are parts of the same process.

The first part of suntanning seems to be a darkening of the pigment already present in the skin. There follows closely upon this a deposit of more and more pigment, as exposure to the sun is repeated, so that a very heavy color screen may be produced in the skin. The tanning process is really more rapid in the skin of most people than is commonly realized, for the manufacture of pigment begins at once, when the skin is exposed to the sun and, within a brief time after the first sunning, pigment is laid down in the skin. But a few short sunbaths are required to occasion a perceptible tanning.

Except in the cases of albinos and some red blondes, pigment is quickly formed in all human beings when exposed to sunlight. It is produced most abundantly in black races, not so abundantly in brunettes as in the blacks and least abundantly in red-blondes. In each type it may be increased to a maximum by exposure to sunlight.

The deepest pigmentation is occasioned by a combination of infra-red and ultra-violet rays. It may occur without any preceding erythema; that is, by gradual insolation without any appreciable burn. In some works on "sunbathing we read about the "tanning rays" or "pigmentation rays" of the sun. All such talking and writing is sheer nonsense. There are no such rays. The sun's rays do not produce pigment; they only occasion its formation. Pigmentation is a vital or physiological process. Pigment is manufactured within the body, out of the elements of food and is deposited in the skin by the processes of life. It is a protective device made by the body itself. If one person tans and another does not, this is not because the sun has power to tan one and not the other, but because one body has full pigment manufacturing ability and the other is deficient in this power. Pigment is manufactured in and by the body and is deposited in the skin by the body, not by the sun. Whether or not you tan deeply depends upon you and not upon any supposed tanning power of the sun. Two people equally exposed to the sun will tan differently--one becoming a dark brown, the other a light tan--and these differences are due to the differences that exist in the two individuals. No amount of sunning will pigment a dead body. Commonly the white patches of skin seen in leukoderma will not tan no matter how often, how long nor how persistently the patient sunbathes.

Tanning may range all the way from very light to almost black, depending on the amount of exposure to which one is subjected and one's pigmenting ability. Contrary to the prevailing view, I doubt that the deep, dark tan can be considered a desirable acquisition. It is my opinion that, both for appearance and for benefit, a light tan is preferable.

In infancy and early childhood, when sunshine is of greater importance than later in life, tanning is a slow process and is almost never (in the white races) dark, even after months of sunbathing. With rare exceptions, a child must be four to six years of age before it will become dark from sunbathing.

It is my opinion that too much stress is placed on the tanning process and too much magic is invested in the tan. I hold that the tanning is merely part of and is concomitant with a general revitalizing process that involves the whole organism and is not confined to the skin.

Nor do I accept, as true, the axiom that "a tanned body is a healthy body." I have seen bodies that were so tanned they were almost black, and their possessors were dying of cancer, or Bright's "disease," or diabetes. Sunshine is no substitute for right living in other departments of life.

Dr. Rollier thinks that pigment acts as a kind of dynamic accumulator and says: "Experience, at least, confirms this by showing that the resistance of the patient is nearly always in proportion to the degree of pigmentation; it acts not only in protecting the skin against the too violent irritation of the ultra-violet rays, but in regularizing the thermic contribution of the sun. Finally it is probable that the pigment receives, furnishes and activates the elements essential to the metabolism of the hormones. Pigmentation is the expression of the deep biological processes of a fermentative and hormonal nature, as demonstrated by Bloch in the skin, by Pinkuseen in the blood, and by Bickel and Ischido in the marrow of the bones."

Jesionek believes that the pigment, itself, passes in solution into the blood and is changed there into substances that act favorably in pathological processes, such as tuberculosis.

The more rapidly pigmentation occurs, the quicker will one receive the full benefit of the sun. Rollier lays great stress on the strongest possible pigmentation, not only to arm the skin against the inflammatory stimulus of the ultra-violet rays, but also because experience has shown that only a strong deposit of pigment in the skin warrants certain success in healing tuberculosis. Pigment cells are also thought to secrete substances which are carried into the blood and beneficially affect the rest of the body--the skin thus becoming an organ of internal secretion. There are some who think that pigment transforms the shortwave rays, which would otherwise act only superficially, into deep-acting, long-wave rays.

Good pigmentation depends upon regular sun bathing. Subjects with fair or red hair do not pigment as readily as dark-haired subjects. These first become a coppery red color and then, light brown. It takes some time before they become at all dark, but under constant sun treatment, even red-haired people will pigment or tan. Brunettes, on the other hand, pigment very quickly. In Egypt the Englishman soon becomes as dark, or even darker in many cases, as the Egyptian or Arab.

Eskimos and polar explorers are poor in pigment. The explorer Shackelton, remarks: "At the close of the night of four months duration our faces were greenish yellow, but the sun soon tanned us again. Yet stranger was the discovery that the eyes of almost all of those which were brown and black become blue or gray during the long night."

I have started a number of blonde and red-haired babies sunbathing from birth and have had them continue to do so on through their infancy and childhood and none of them have freckled. This has led me to believe that were all such types given sunbaths from infancy, the freckles that bother them so much would not develop. It would seem that freckling is due to a certain loss or disturbance of the ability to tan as a result of long denial of sunshine during the formative years of life.

As these babies and children have all been provided with superior nourishment, it may well be that nutrition also plays a very important role in this matter. The worst cases of freckling we see are in red-heads and, as these are in children and adults whose nutrition is far below ideal, it may be that poor nutrition is at least partly responsible for such undesirable developments.

I have witnessed the development of thousands of large freckles on the affected portions of the skin of a man suffering with leucoderma. As the man was under my care for but a limited time, there was no opportunity to determine what may have been accomplished ultimately, but I consider the formation of the freckles to be indicative of the possibility of complete remedying of the condition. It should be understood that sunbathing in this patient was accompanied with other Hygienic measures, such as fasting, improved nutrition and a correct mode of living. I do not think for a minute that sunbathing will remedy leukoderma.