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. I have myself a strong penchant in favour of good hard scientific experiments with apparatus and, if the clairvoyant testimony stood by itself without any experimental evidence to support it, I should make no mention of it here. But I think that in common justice we ought to admit that the statements of the clairvoyants are, in the main, in close agreement with what we should expect from the indications afforded us by the experimental work which has at present been done. In continuing the latter we shall be well advised to keep the former in our minds as furnishing, at least, useful hints for our guidance. On the strength of the various considerations discussed above, I am disposed to extend the four dimensional hypothesis as follows: "Connection between the three- and four-dimensional vehicles is maintained by means of a substance of peculiar properties, which is intimately connected with the nervous system in the conscious functioning of which it is an essential factor. States of partial or total anæsthesia or insensibility are accompanied and probably caused by the extrusion of this substance from the body." We are now faced by the problem of the constitution of this substance. To this there would appear to be two possible solutions. The first of these is that favoured, apparently, by the occultists and the exponents of the "perisprit" doctrine. The second is that to which I am personally inclined at present. According to the former of these two hypotheses, the E.D. is composed of a sort of "rarified matter" by which, I take it, is meant matter possessing a smaller complexity of organisation than that with which we are normally acquainted. This would appear to be more especially the Occult view; although on technical details of this kind there is a somewhat unfortunate lack of precision and even of unanimity among Occult authorities. A variation on this is the idea that whereas ordinary matter is the result of vibratory, or other periodic, disturbances in the ether of a certain frequency, the "matter" of which the E.D. is composed is the result of similar disturbances of a greater frequency; that it is matter transposed into a higher key so to speak.