"The evolution of the centres is a slow and gradual thing, and proceeds in ordered cycles varying according to the ray of a man's Monad. (p. 173) The centres in physical matter are recognised as being simply focal points of energy located on the etheric body, and having a definite use. This use is to act as transmitters of certain forms of energy consciously directed by the... Self, with the intent of driving the physical body (which is not a principle) to fulfil egoic purposes. (p. 1155)."