The astral body is a precise counterpart of the physical body, its organs, its parts, its centres, and its cells. In fact, the astral body is the pattern upon which the physical body is materialized. The astral body is composed of an etheric substance of a very high rate of vibration. In one sense it may be considered as a very subtle form of matter--in another as a semi-materialized form of force or energy. It is finer and more subtle that the rarest vapors or gases known to science. And, yet, it has a strong degree of tenacity and cohesiveness that enables it to resist attacks from the material side of nature. As I have said, each organ, part, centre or cell, of the physical body has its astral pattern or basis. In fact, the physical body has been built up, in whole and in all of its parts, on the pattern and base of the astral body. Moreover, in case of impaired functioning of the physical organs or parts, and impaired activity of the physical body, its limbs, etc., if we can manage to arouse the activities of the astral body we may cause it to re-materialize or re-energize the physical body, and thus restore health and activity to it. If the liver, for instance, is not functioning properly, we proceed to start up the activities of the astral counterpart of that organ, to the end that the physical organ may be re-energized, and recreated in a measure. All true psychic healing work is performed on the astral plane, before it manifests on the physical. At this point, I should also call your attention to the effect of "prana," or life energy, in some cases of healing. This prana is what Western healers mean when they speak of "human magnetism" in their healing work. So far from being an imaginary force, as claimed by the physical scientists and materialists, it is known to all occultists as an active principle of the human body, and as of great efficacy in the psychic treatment of disease. I shall mention the details of this form of treatment as we proceed--I mention it at this place merely to call your attention to the fact of its existence.