Breath is vouchsafed to the senses as far as their reach of perception goes. Breath makes a complete circle within the body, entering through the nose, passing through the brain and down the spine, ascending again through the abdomen and lungs, going out through the nose. When breath reaches the higher spheres, the senses, unless developed, cannot follow it there. Though one circuit of the breath takes a circle through earthly and heavenly planes, yet to an average person it seems as if some air goes out and comes in. But the mystics follow this chain of breath in the pursuit of the Infinite and, by holding on to it at the sacrifice of all earthly temptations which lead one on to death, they drive their lives towards immortality.