Some aspects of healing work are beginning to be understood from scientific standpoint. The most important standpoint for formulating a theory of how Reiki involves the electromagnetic fields generated by all living things.
It has been known for some time that electric currents flow through the body. These currents flow through the nervous system and are one of the ways the body regulates itself. The nervous system is connected to every organ and tissue in the body and signals flow through it from the brain to regulate all bodily activities.
Whenever you have an electric current flowing through a conductor, a magnetic field surrounds the conductor. The electric current flowing in human bodies generate magnetic fields called biomagnetic fields that penetrate and surround the human body.
The heart has the strongest biomagnetic field and has been measured to a distance of 15 feet. The brain and all organs of the body have their own biomagnetic fields surrounding them. The fields pulsate at various frequencies and interact with each other. An organ will have specific frequency when it is healthy and will move away from this healthy frequency when it is not. The sum of all biomagnetic fields forms a large aggregate biomagnetic field that surrounds the body. It is of course similar to what we call the aura. Therefore, the biomagnetic field may be one of the main components of the aura, although there may be other aspects to it as well.
The fields interact with other fields near the body, including the fields of other people. The principle is called induction and means that one magnetic field can have an effect on another, inducing changes in the field as well as changing the strenght and frequency of the electric currents flowing in its conductor. So, the biomagnetic field of one person has an effect on the biomagnetic field of another. Th eeffect can influence the well-being of each person as well as the functioning of the organs and tissues.
So, from a scientific standpoint, a person's being does not stop at the skin, but extends out into the surrounding space. Ona level of personal experience, we know it to be true, as we have all felt the presence of others. Now it has been proven and explained scientifically.
When a healer places her/his hands near a sick organ and begins to heal, the biomagnetic field emmited from the healers hands becomes much stronger than the one emmited by the sick organ. The frequency of the biomagnetic field of the healers hands also begins pulsing at the healthy frequencies needed by the organ. Because the healers magnetic field is much stronger than the sick organ, it induces the healthy frequencies into the field of the sick organ, causing it to adjust its frequencies back into healthy range. The adjustment in turn affects the electrical currents flowing in the cells and nervous system within and around the organ, as well as it's biological processes, and healing takes place.
Taken from the book "Spirit of Reiki", one of my most favourite books on the subject.