The exponents of some yoga methods have minutely described, in their books, seven centres or "lotus-flowers" or "whirling wheels" as they are termed, which are situated in the "soul-body" at intervals from the base of the spine up to the crown of the head but which work in intimate relation with similar places in the physical body. Elaborate diagrams have also been drawn to make plainer their claims about this remarkable feature of spiritual anatomy.
On its practical side, the system affords a basis for redirecting attention, a method of providing useful points for concentrating it as a yoga exercise. It is easier for undeveloped minds, which are unable to entertain abstract metaphysical ideas or to meditate upon them for any length of time, to picture the "centre" in the throat, for example, and fasten their attention upon that. To encourage these novices to undertake such meditations they are lured with the bait of miraculous powers, a different power being associated with each "centre," or with that of visions of gods and goddesses, a different deity being associated with each centre. If the novice practises, he will gain some tranquillity, even if he fails to unfold any powers.
-- Notebooks Category 4: Elementary Meditation > Chapter 5 : Visualizations, Symbols > # 106
