If we take, for a moment, a swift survey of the evolution of forms, we shall find that the building of organs follows the exercise of life-functions; in the earliest forms there are no organs, but the functions of life are present and active; the creature breathes and assimilates, circulation goes on; but there are no organs for digestion, no organs for breathing, no organs for circulation; the whole body does everything. But as evolution proceeds and definite organs are formed in the physical body, in the nervous system, and as later, in the astral body, chakras or astral centres of sensation are formed--as this goes on, we find a more specialised being developed with definite organs. Always the organ comes after the function, and through the organ the function expresses itself more and more perfectly. That is a fundamental principle. And do not forget that in this you are on what is thought the safer ground of western science. You do not find an organ appearing before the development of its function. You always find the life-impulse first, and then the moulding of the matter into a shape which enables that impulse to express itself more perfectly. If we trace evolution from the amœba upwards we find differentiation and specialisation becoming more marked the whole way through, yet man himself turns round, and with the very brain which has been formed under the vibrations of intelligence he reverses the whole process, and asserts that thought is produced by the brain; but every organ is formed as the organ of a function, it is produced by life, and is not its creator. This process goes on until the necessary organs are made and the nervous system is linked to the chakras in the astral body, chiefly through what is called the sympathetic system. There are certain nervous cells of a peculiar kind in that system, of which modern science does not say much, beyond giving you the forms and contents, and these are the links between consciousness in the physical body and in the sensory body. Then come the chakras already spoken of as the centres for the working of consciousness in the astral body. A similar process goes on in the mental body under the action of thought-impulses, and there we have also an organised body able to respond to different kinds of thought, and thus to serve consciousness as its organ for expression in the mental world. As we grow mentally we build our organs for consciousness.