This section is from the book "The Hygienic System: Fasting And Sun Bathing", by Herbert M. Shelton. Also available from Amazon: The Hygienic System Vol III Fasting and Sun Bathing.
The body's third defense against the sun is that of getting out of it before an over-dose has been received. Even animals whose bodies are not nude, but are covered with hair, feathers or thick, heavy scales, instinctively avoid over-exposure. They may be seen actively feeding in the sun in the morning, when it is cool, but they retire to the shade before noon and remain there until later in the day, when they come out again. Birds, beasts, insects, even the red and black ants, observe this simple precaution.
Sunburn is distinct from suntan. It is a real burn and injures the skin just as much as fire or scalding water. It results from an overdose of sunshine in those who lack adequate protection against the sun's rays. The sun's rays may penetrate deeply and burn the underlying tissues.
When exposure is too prolonged before pigmentation or after most or all of a previous pigmentation has been lost, more or less inflammation follows. Burning, often severe blisters, and peeling result. Sunburn is usually superficial, and quickly heals without leaving scars. As in other burns, there are three degrees of sunburn.
First degree burn is a slight redness (erythema) which causes little or no discomfort and results in no harm. The redness is due to the excess of blood in the skin.
Second degree burn results when you stay in the sun until the skin glows like a boiled lobster. It is very painful and accompanied with fever. Blisters develop, burst and discharge their fluid contents over the body. There is much itching and peeling of the skin. There may be diarrhea, vomiting and other unpleasant symptoms as a result of the terrible beating taken by the nervous system.
A third degree burn results in a sloughing dermatitis and may end fatally. Inflammation of the brain, stomach and intestines, blood poisoning, hemorrhages and tetanus are said to follow as complications of severe burns.
Sunburn does not show up immediately. One burns without realizing it until hours later. The only safety lies in not overdoing the sunbathing until a protective coat of tan has been built.
The manufacturers of "suntan preparations" have posed the dilemma of acquiring a tan without a burn. They propose to solve this problem with their various lotions and oils. This is a commercial program and does not represent a sane approach to a simple problem that is simply and easily solved without cost.
Sunburn occurs when the unprotected skin is exposed to the sun's rays too long. Short of this, only tanning occurs. It is not necessary to get sunburned in order to tan. Indeed, the purpose of tanning is to prevent sunbuming. As tanning occurs from exposure short of burning, it is easy to acquire a tan without a burn and without artificial preparations applied to the skin. To avoid burning, it is only necessary to avoid excessive exposure of the body or any part of it to the sun until a good protective coat of tan has been acquired. Those impatient individuals who seek to get a coat of tan in a hurry and those foolish individuals who try to get enough sunshine on the first day of their vacation to last the whole year, are almost sure to burn themselves.
At the shore, on the sand, especially white sand, or in the water, more sun's rays strike the body, due to reflection from the sand and water, and it is much easier to get an overdose. Burning will result in a much shorter time at the beach. Even those with a light tan will readily burn in such places.
A thin haze over the sun does not exclude its ultra-violet rays and will not prevent burning. A cool breeze will not prevent burning. It is not the sun's heat rays that produce sunburn. Do not be misled by the fact that it is cloudy or partially cloudy. A very severe burn may be produced by staying in the sun too long under such conditions.