It must be remembered that observations of this kind contain, in themselves, no sort of "supernatural" element, although they may, of course, receive the most strange and erroneous interpretations at the hands of the uninformed.
When we turn to Occult literature we find that the theory of the E.D. is worked out in considerable detail. It is said to be violet-grey or blue-grey in colour and to interpenetrate the physical body. The "health aura," i.e., the physical aura dealt with by Dr. Kilner, is said to be that part of the E.D. which projects beyond the physical body.
It is stated that the physical body and the E.D. are not normally separated during life, although in certain nervous conditions the E.D. may be more or less extruded from the physical body. (Compare this with the diagnostic researches of Kilner.)
"Anæsthetics drive out the greater part of the E.D., so that consciousness cannot either affect or be affected by the dense (physical) body. In the abnormally organised persons called mediums, dislocation of the etheric and dense bodies easily occurs, and the E.D., when extruded, largely supplies the physical basis for 'materialisations' (and for Crawford's structure. W.W.S.)."
"In sleep, when the consciousness leaves the physical vehicle which it uses during waking life, the dense and etheric bodies remain together.... At what is called death the etheric double is drawn away from its dense counterpart by the escaping consciousness; the magnetic tie existing between them during earth life is snapped asunder...."
(Taken from "The Ancient Wisdom.")
In other passages it is stated that the E.D. is connected with the physical body by a filamentary structure, "The silver cord," and that so long as this is unbroken it is possible for connection between Consciousness and the physical body to be re-established, but that when it is broken as occurs in death, the separation is final.
Finally it is definitely stated that this E.D. is a quasi-physical structure, disintegrates in the same way as the physical body and is perceived by a mere heightening of the ordinary visual faculty.
Let it be clearly understood that I do not wish one whit more importance to be attached to this last-quoted evidence than each individual reader may choose to assign to it and I fully sympathise with those who prefer to allow it no weight at all.