The etheric body surrounds the physical body and is much finer than the physical body. Currents and organs of wonderful variety and splendour are active in it. The etheric body contains the same organs as the physical body. It has a brain, heart, eyes etc. They represent the forces which formed the corresponding organs. It is as if one cooled water in a vessel until it becomes ice. In this way you should picture the arising of the physical organs through the densifying of the etheric organs. The etheric body extends only a little beyond the physical body.
Source: Rudolf Steiner – GA 94 – THE GOSPEL OF ST. JOHN: Lecture I – Berlin. 19 February 1906