Different conditions and the changes that take place in the world have their effect upon the mind, and the different conditions of the mind have their effect upon the body. As bodily illness makes man irritable, confused and exhausted in mind, so different conditions of the mind cause health or illness in the body. The link between the body and the mind is the breath, a link through which the influences of the body and the mind are exchanged and work upon one another. By the use of breath in physical culture the health and vigor of the breath is projected, so to speak, upon the mind. By the use of concentration through the breath the light of the mind is thrown upon the body, which takes away from the body all heaviness and stiffness, making it light and exhilarated.

Breath in this way acts like a ball in tennis thrown from one side to the other, and the force of its movement comes from the side from which it is directed. Therefore when it is directed from the body to the mind the mind becomes subject to the influence of the body, but when from the side of the mind it is directed toward the body, in this case the body becomes subject to the mind. Very often dervishes and faqirs in the East, many of whom live upon alms and go several days without food and spend many nights in sleepless vigil, do things which are difficult for a wrestler, a boxer, or any other muscular person.

Some dervishes practice jumping into fire, standing for hours in the water, sitting or lying on iron pricks, thrashing their bare arms and legs, cutting themselves with knives and swords, and all such things beyond the power of a physically strong man. Often a physically strong man suffers in proportion to his strength when he is exposed to pain or torture.

This explains that though the power of breath is the main source of physical development, yet breath is the principal thing in the development of mind, in which the influence of the breath is more valuable.