In some form or other radiant energy plays many parts in all animal as well as plant activity, so that an investigation of the whole effects of the sun's actions on animal life is desirable. We know that heat serves to set in motion the wound-up "machinery" of the germ-plasm; it touches-off the vital spark in the egg and is essential to the continuation of the evolution of the new being.

This does not justify the present efforts to break radiant energy up into its constituent parts and use each part as a specific cure for a specific "disease," as is attempted. In a prior volume we saw how this same mistake is being made in the field of diet. The old conception of drug specifics has been carried over into the fields of dietetics and helio-hygiene.

We see this in the treatment of so-called "diseases" with infrared lamps, ultra-violet lamps and spectro-chrome lamps. One type of ray is employed for one form of impaired health and another wave-length is employed in another condition of impaired health. The conception of the unity of sunlight and the need for balance between its various rays is missed. We are almost justified in saying that the same Law of Minimum, which we saw operating in food, operates also in light.

The use of colored lights in treating illness is based on the obsolescent fallacy that there are specific "diseases" and that different "diseases" require different treatment. Colors are employed to stimulate and inhibit function.

Charles Fere made some experiments with regard to the association of light and muscular force. He declares that a light colored light flashed in front of the eyes will greatly increase muscular strength. If this is kept on for "too long," however, muscular strength diminishes. This is purely a method of stimulation and cannot be of value in correcting the cause of the patient's troubles. Red is irritating--blue is soothing. The alternate use of these colors is supposed to increase metabolism. It is much like the alternate use of hot and cold water.

Most of the effects attributed to color are psychological and fail to appear when the subject is blind or blind-folded. Association has been shown to play a big part in their psychological effects. The effects are not inherent in the color.

Green is termed a negative color, but those practicing chromotherapy are advised to include it among their colors "in order to impress the minds of their patients." Although this color is considered unnecessary, "we all know how impressed some people are by a prescription of 'Mica parris'."

In the chemical laboratories of the firm of "Lumiere de Lyon," manufacturers of photographic supplies, the workmen who spend all of their time under red light become nearly mad with anger. The substitution of violet glass panes for the red ones calmed the men. This is a psychological effect produced through the eyes. Violet colored goggles would doubtless have produced the same results.

Finsen placed about twenty worms in a box and covered it with different colored glasses, then exposed it to the sunlight. All the worms assembled under the red glass. When butterflies were used in the same experiment, they crowded under the blue glass. This difference was explained by the fact that whereas butterflies are very active and love the sun, some of the beneficial rays of which pass through the blue glass, the worms love the dark and crowded under the red which only allows the hot rays to pass through.

This would seem to be merely an example of each type of life seeking that condition which more nearly approximates its normal habitat, and may be properly called psychological.

The employment of colored light, different colored wall papers, different colored clothing, etc., while of certain psychological significance, must be relegated to the realm of the hygienically unimportant.

Due to various factors there is a strong tendency on the part of doctors of all schools to rely on artificial light and neglect the light of the sun. This is very deplorable, and may, we trust, not always be the case.

Every imitation of nature is incomplete and seldom, if ever, satisfactory. Physicists have not been able to construct artificial light that possesses the unity and balance of sun-light. There are several marked differences between sunlight and artificial light, and these differences produce corresponding differences in results. Sunlight has inestimable advantages over all forms of artificial light.

Quartz light begins at yellow, being totally lacking in red; but is from 1,500 to 1,800 A.U. richer in the short-waved ultra-violet rays than sunlight, going beyond 1,800 A.U., while sunlight stops at 3,000 A.U. ultra-violet rays shorter than 2,900 A.U., as produced by the carbon-arc and mercury-quartz lamps and other artificial sources of light are destructive of animal tissue.

These short wave ultra-violet rays are totally lacking in sunshine and are thoroughly irritative to the skin and eyes, producing inflammation. The milder ultra-violet rays of the sun are counter-balanced by the red rays, which neutralize ultra-violet. Red is lacking in quartz light.

The balance between red and violet, in sunlight, is beneficial to the eyes and skin. The cells of plants and animals are nicely adjusted to the happy combination of visible and invisible rays of the sun. The complete lack of red rays and the excess of irritative ultraviolet in quartz light constitute a double danger.

The colors of the sunlight spectrum merge into each other, while in quartz light these are divided into distinct lines. The sunlight spectrum is termed the band spectrum, the quartz spectrum is denominated the line spectrum. This is an important physical difference between the two types of light and may be partially responsible for the differences in their effects.

The quartz light develops such an amount of free active oxygen that this soon renders the atmosphere of the room unbearable, and causes malaise and headache.

An excess of ultra-violet rays, as found in quartz light, may easily prove injurious to health. Quartz light gives an excess of short, irritative rays, lacks other counter-balancing rays--lacks balance--and makes the risk of burning the skin and severely injuring the eyes with the "artificial sun" very great. The shorter ultra-violet rays, which render quartz light so irritative, are not found in sunshine.

Neither the ultra-violet rays nor the red rays are the exclusive metabolic agents of light. The combination of red and violet, of heat and chemical rays, is the secret of the sun's beneficial influence. This balanced combination is not found in any artificial light.

The ultra-violet rays destroy bacteria and animals with bare, unpigmented skins. Snails die in twenty-four hours after exposure to these rays. Tadpoles and flies become torpid after an exposure lasting three hours and are killed in five hours. Young grass-hoppers die in two or three days. These facts reveal the dangers that lie in the use of the powerful ultra-violet rays from the doctor's lamps, when compared to the more beneficial rays from the sun which do not so easily or quickly destroy bacteria and young animals.

One marked evidence of the harmfulness of the ultra-violet lamp, is the special precautions that are necessary to prevent it from producing damage, owing to the painful effect of its short wave rays on the skin. The eyes in particular must be protected, either by goggles or by a dark cloth around the head. Conjunctivitis is very common, even from looking for a few seconds at an arc-lamp, if the eyes are not properly shielded. "Quartz light," says Thedering, "has the richest content in short-wave rays; radiation of the skin of even a few minutes duration causes intense burning, and if the naked eyes are exposed to the light, painful conjunctivitis will result." This condition is exceedingly painful. Sunlight does not produce it. Goggles are not required while taking sunbaths.

It is insisted that our blood has the property of transforming rays and is able to equate the light from a quartz lamp to natural sunlight. This is a mere assumption and lacks verification.

Dr. Thedering, of Germany, and Prof. Roat, of Frieburg, both noted that the super-abundance of irritative ultra-violet rays in the quartz light causes the body to surround itself with such a thickened covering of pigment that this "shuts out the rays like a coat of armour, and the effect of the light bath becomes nil." Dr. Thedering says "the treatment quickly came to a dead end, and the cure made no further progress." This effect follows long light baths, but is claimed not to follow the short ones. Such results do not follow the sunbath.

For the orifices--mouth, throat, nose, ears, rectum, vagina, urethra, bladder, stomach, etc.,--special rods are made of quartz crystal. These are employed for local or symptomatic treatment and have no value.

The various lamps on the market, both for professional and home use, vary greatly in their radiant intensity under the spectral distribution of their energy output. Many of them deteriorate after use, even for a comparatively short time. Some of them give off no ultraviolet rays at all. The carbon-arc lamp is the nearest approach to sun-light, but the percentage of short destructive rays emitted by the lamp is high.

Reddie Mallet, in Nature's Way Monthly, April, 1929, quotes a report issued under (English) government authority, which, to use his words, "Pours scorn upon the professed effects of manufactured light, and challenges those advocates who engineer its wonders to prove that its claims are justified."

The report says: "The use of artificial light, to supply only what the right food can give, is merely wasteful."

Again, "It commonly costs three or four shillings to give, by light-treatment, an effective supply of Vitamin D that would cost less than a penny if given by the mouth in the form of cod-liver oil, or otherwise." This is a huge difference in cost.

The report says: "There is no present reason to know that artificial light can do more in this way than a mustard plaster."

Finally, it says "It is made obvious that proper food, exercise, and fresh air are greatly preferable to indoor sessions around a lamp."

It cannot be denied that the ultra-violet lamp possesses a limited amount of the influence of the sun. Plants may be grown in artificial light, but they lack the rugged constitution of plants grown in the sunlight. They may be made to grow more rapidly than plants in the sunlight by subjecting them to light for longer hours than the revolving world does, their rate of growth increasing or decreasing with the decrease or increase of light, but forced growth of this kind proves to be defective in more ways than one. The plants do not have the same color, nor equal structural soundness, nor are their flowers and fruits equal to those of plants grown in the sun. The sun has no rival--whether irradiating plant or animal.

Animals grown under artificial light thrive better than those grown in the darkness or under glass, but they are not the equal of animals that have been irradiated by the sun. The lamp cannot produce all of the effects of sunlight.

In Europe, a distinction is made between a light-bath and a sunbath. Rikli advised taking light baths very early in the morning, before sun-rise. The light bath is also taken in cloudy weather. Rikli established his place in 1855. Ten years later he began the practice of air bathing. In 1869 he wrote: "It is my firm conviction that the light and air baths must be the foundation of the atmospheric cure, while the sun baths are the necessary auxiliary method."

Many Europeans--British and Continental--give sun bathing a secondary place. Certain English Naturopaths contend that sun-baths taken in a glassed-in room, the sun filtering through the glass, give satisfactory results. It seems to me quite obvious that these men have missed the true significance of sun bathing, and do not correctly understand its effects upon the body. I do not deny that the light-bath, as distinguished from the sun-bath, has its value; but I am inclined to think this value comes as much from the air bath as from the reflected light.

In several European institutions many things are thought to be able to replace the sun-bath, and many things are used in connection with sun-bathing which are thought to add to its effectiveness. In certain Swiss and German institutions, packs or hot potato baths are used to "replace" the sun bath. Dr. Monteuius, of France, says: "The sun-bath may be replaced' by various hydro-therapeutic applications of vapor or electric light baths." He also says, "The light bath practice is associated so intimately with hydrotherapy that they may be said to go hand in hand with one another."

Lotions, douches, vapour baths, packs, fomentations, sand baths, bare-foot walking, hot baths, etc., are employed in connection with and as substitutes for sun-bathing, both in Rikli's place and in other European institutions. There is too much hydrotherapy and not enough sun. Burying a man in sand and thus excluding the sun, except its heat, from his body may, "weaken by inducing excessive perspiration," to quote Dr. Monteuius, but it does not give him any of the benefits of the sun. All the monkey work of hydrotherapy should be avoided and no effort made to substitute these for the sun's rays.