As in the case of the other elements, which have been already dealt with, man cannot do without sunlight. The sun is the source of light and heat. If there was no sun, there would be neither light nor warmth. Unfortunately we do not make full use of sunlight and consequently we are unable to enjoy perfect health. Sunbath is as useful as ordinary water bath though the two cannot replace one another. In cases of debility and slow circulation, exposure of the uncovered body to the morning sun acts as an all-round general tonic and accelerates the metabolism. The morning sun has the largest amount of ultra-violet rays which are a most effective component of the sun's rays. If the patient feels cold, he should lie in the sun covered up and gradually expose more and more of his body as he gets use to it. One can also take the sunbath pacing up and down in the sun without any clothes on, in a private enclosure or in other place away from public gaze. If such a place is not within easy reach, one can just cover up the private parts by trying up a piece of cloth or a langoti and expose the rest of his body to the sun.
I know and many persons who have been benefited by sunbaths. It is a well known treatment for tuberculosis. Sunbaths or heliotherapy is no longer confined to the sphere of naturopathy. Orthodox medicine has taken it up from naturopathy and developed in further. In cold countries, special glass buildings have been constructed under medical supervision, so that the glass lets in the sun's rays and at the same time protects patients against the cold.
Sun treatment often results in the cure of intractable ulcers. To produce sweating I have made patients lie in the sun at about 11 a.m. , i.e a little before midday. The experiment has been successful and the patients are soon bathed in sweat. In these cases the head should be protected from the sun by means of a cold mud poultice. Banana or any other leaves can keeping the head cool and well protected. The head should never be exposed to strong sunlight.