It is far too early yet to say that the extrusion of this sensitive substance is an invariable concomitant of insensibility; but at present the evidence--assuming it to be reliable--does seem to point that way. When we have made an exhaustive study of what happens to the "aura" during sleep, in various states of hypnosis, in local and general anæsthesia and in death we shall be able to draw more definite conclusions on the subject. I shall now turn to evidence of a more general type which deals with the existence of this mysterious substance viewed as a whole rather than with this or that indication of its presence or properties as did the previous experiments. There are many references in Psychic literature which bear on the point and the general trend of them seems to be that the substance we have been considering is not, normally, entirely formless and distributed fortuitously through the body but that it forms an exact counterpart of the latter or, to be more strictly accurate, of the nervous system. Lombroso states that Durville has succeeded in separating this "replica" experimentally from the physical body. ("After Death--What?"). He says that it seemed to be connected with the body by a sort of cord and that the patient under observation was able to see through opaque objects and to discern events at a distance. The apparent sense organs of the replica worked, while those of the physical body were put out of action. When approached, it excited a sensation "like that produced by cold, by blowing air, by shivering," and if the hand were placed in it a cold, clammy sensation was experienced. Compare with this last statement the remarks of Crawford on the sensations produced by inserting the hand into the midst of the levitating structure. M. Leon Denis in "Christianity and Spiritualism" quotes experiments from the "Revue Spirite" for November 1894, and alleges that de Rochas and Barlemont obtained simultaneous photographs of the body of a medium and of the exteriorised "double." A long account of experiments on these lines by Durville appears in the "Journal de Magnetisme" for 1907 and 1908 but although they tend to confirm the ideas at which we have already arrived, there is nothing to be gained by going into their details here. A very interesting case which has a considerable bearing on the subject is given in the Proceedings of the Society for Psychical Research, Vol. VIII, pp. 180-193. The following is an abbreviated account: The narrator is a physician and the case seems to have been singularly well attested and was carefully scrutinised by no less a critic than Dr. R.H. Hodgson.